The Power Upgrade Primer
#1
05-26-2012, 08:06 AM
The Power Upgrade Primer
The Power Upgrade Primer
The purpose of this thread is to provide an understanding of the power upgrade options, and the safety concerns that some members may have. Hopefully this will facilitate a discussion that will help in selecting the upgrade path that leads to your own Holy Grail of performance.
I won’t be explaining how the internal combustion engine works, but rather the specific factors related to modifying both normally aspirated and super-charged engines. This will make for an easier read that will move along quicker, and focus on what we need to know. I hope others will chime in and add to the discussion.
Let’s start with the basics, and discuss the #1 safety concern when tuning for more power…
Detonation
Also known as pre-ignition or knock, this is when the air-fuel mixture in the combustion chamber “pre-ignites” before the ECU generates its well-timed spark at the plug. This early combustion applies an opposing force to the movement of the piston which can cause damage to the piston ring-lands that hold the rings in place. You may hear a “pinging” noise, or more likely feel it as loss of power as the engine’s knock sensor detects it and the ECU responds by reducing engine power gently, or abruptly in more severe cases of detonation.
Factors that cause detonation individually, or in combination with others, include inadequate fuel octane, too lean an air/fuel ratio, too advanced ignition timing, too much boost, and too high air density. Each of these factors affects engine power, and tuners use them to increase power as much as possible. When done carefully they can provide safe power, but it can also be said that everything that produces power moves you closer to the threshold of detonation, and Jaguar will have been obsessively careful to set up the engine in the factory to avoid catastrophic engine failure at all costs, and under the most extreme operating conditions imaginable. Not so coincidentally, but these are the factors available to us to evaluate for our specific uses, and to see where we can modify to make power gains without sacrificing safety.
Let’s look at these factors individually…
Octane Level
Octane is the measurement of the fuels resistance to burn, with 91 (premium) having a higher resistance to burn than 89 and 87 (regular), and the greatest resistance to pre-ignition. Premium is specified for these engines, but the manufacturer knows that there are a number of reasons that fuel of insufficient octane and quality may end up being used on occasion, and will have likely set-up the engine conservatively enough to handle low octane without catastrophic engine damage. The engine’s knock sensor would likely detect the poor fuel octane and adjust engine operation and power output to cope with that.
Why do we care about octane levels? Because higher octane fuel allows the ECU tune to be “mapped” to run a leaner air/fuel ratio and/or a more advanced ignition timing map…and both will allow the engine to make more power! There will be a pretty significant factory safety margin there to be tapped into by the diligent enthusiast, and that’s exactly what ECU “chipping” or re-tuning does. Now consider how the ECU could be tuned if we ran even higher octane! See ECU Tuning below.
Air-Fuel Ratio
A lean mixture that contains higher ratios of air will make more power than a richer mixture. An air-fuel ratio of 14.5 parts of air to one part fuel (14.5:1 AFR) is about ideal for best fuel economy for cruising, but too lean to avoid detonation under hard acceleration. An AFR of 13.0:1 would make more power than a richer 10.0:1 would make. Lean AFR’s burn hotter, rich burn cooler, and that affects combustion chamber temperatures… and that has a direct bearing on the likelihood of engine detonation and/or engine wear. The ECU is programmed with AFR maps, which is a table of values covering all engine operating conditions from idle to redline rpm, light load to full throttle and boost. See ECU Tuning, and reducing combustion chamber temperatures below.
Ignition Timing
The ECU contains ignition maps that determine the precise moment that the spark plug will fire to ignite the air/fuel mixture in the combustion chamber under all operating conditions. Since it takes a moment for the mixture to fully combust, the spark plug fires as the piston is still rising, and just before top dead center. The combustion then forces the piston down on its power stroke and generates the power that turns the wheels. The most power can be made from this combustion if it’s ideally timed to apply maximum force to push the piston down on its power stroke. So the objective in tuning for increased power is to advance that ignition as much as possible without full combustion taking place when the piston is still moving upwards. If that were to happen it could cause serious damage. See ECU Tuning below.
Boost from Supercharger
Super-charged engines make more power because they force more air volume (called Mass Airflow) into the combustion chamber than a normally aspirated engine drawing air in at only atmospheric pressure. The ECU injects more fuel to create whatever the desired air/fuel ratio is. When more air and fuel combust, they do so with more energy, and the engine makes more power. So it follows that maximizing the amount of air through the engine is one goal in maximizing power. I’m told the super-charger on the 5L forces in extra air at 10.2 psi of pressure above atmospheric. Changing the diameter of the pulley that drives the super-charger will increase the boost pressure to force in more air and make more power. After-market pulleys are available upgrades that commonly add 1.5, 2.5 or 3 pounds of boost pressure. Increasing boost also increases intake air temps unfortunately, and that’s discussed in ECU Tuning below.
Air Density
The density of the air is also important because higher density air contains more oxygen particles that make more power than low density air. You may have noticed your engine makes more power on cooler days, and that’s because cold air is denser. Forcing air into the engine with pressure causes the Intake Air Temperature (IAT) to increase, loosing density, so they use intercoolers to reduce the IAT’s to increase density. Our engines have a pair of air-to-water intercoolers, but when ambient air temps are hot in the summer, or when the engine has been run hard for an extended period of time, the intercooler loses its effectiveness and the intake air density lowers, and engine power along with it. If we can increase the effectiveness of the intercooling we can make more power. See intercooling upgrades.
ECU Tuning
We discussed how running as lean an AFR as possible, without causing detonation, would make more power. And the same with running as much ignition advance as possible. The factory has programmed the ECU with values for both that will be safe if the user uses poor quality gas under extreme conditions for warranty purposes. If a knowledgeable enthusiast was dedicated to running only premium octane gas then his ECU could be re-mapped a little more aggressively to make more power and still be just as safe as the car driven on lesser grader fuel. If he ran “race” fuel (high octane) he could have that ECU tuned much more aggressively. Or he could raise octane by using water/methanol injection and tune more aggressively.
Water/Methanol Injection
Water and/or methanol is sprayed into the intake airstream through a nozzle, and plumbed back to a reservoir with a pump that is activated at some level of boost. It sometimes shares use of the windshield washer reservoir. As the fluid is injected it mixes with the intake air. Some vaporizes, and as it changes state from fluid to gas heat is absorbed, lowering air temps…and increasing air density. Some water droplets aren’t vaporized, and make their way into the combustion chamber where they lower intake air temps. Both of these can be positives if accounted for in the ECU tune.
High Flow Catalytic Converters and Cat-Back Exhaust Systems
Volumetric effficiency (VE) is a measure of an engine's ability to ingest airflow at any given pressure. Any method of improving VE will make more power across the entire powerband on a supercharged engine. The easiest way to do that is to reduce exhaust restrictions, with the catalytic converters probably being the largest restiction, and the rest of the exhaust system being the next. Extra power is made on the XKR-S by improving both. Cats are required by law, but some "high flow" cats may have the required C.A.R.B. approval and can be used. I've removed the cats from two other sports cars that I use on the track...and it made a huge difference. I suspect the stock resonators and mufflers with the active by-pass are probably pretty good, but there's bound to be a few ponies available, and it may be worth it to you just for the increased exhaust snarles.
ECU Re-mapping
Viezu (Germany) is a major supplier of ECU re- maps for the after-market industry, and they supply several vendors…if not all of them. Claims may vary slightly from one vendor to another, but the differences you would see between various dyno results will be from the differing types of dyno’s used, and normal individual engine power variations.
The standard ECU re-map offered will run slightly leaner air-fuel maps, and slightly more advanced ignition. Both can provide slightly improved throttle response. It’s programmed into the ECU by computer download through the OBD port under the dash. Gains are advertised as around 50 hp for the 5L S/C engines, and more fully require the use of premium octane fuel to make those gains, and provide protection from detonation. They also remove the 155 mph factory speed limiter…for those that find that too restrictive!
Whether that standard ECU re-map could safely handle additional boost from a pulley up-grade is unknown, although a vendor on JF claims to make an adjustment for that, and claims an overall power gain of around 85 hp. They likely dial back the fuel and ignition maps to avoid detonation. Now what if we ran higher octane to ward off detonation instead of dialling back the maps…more power gains would result! And if we increased octane by using water-methanol injection we’d increase power more by increasing air density! Maybe the standard ECU re-map is all we need…or maybe we don’t need a re-map at all….
What if instead of a re-map we took advantage of the conservative AFR and ignition by adding minimum 2.5 psi boost with a pulley upgrade. The stock map and decent gas should protect adequately against detonation. The richer fuel mixture also has the effect of reducing in-cylinder combustion temps.
How about running a 3 lb upper pulley, or maybe do the lower pulley also for even higher boost? Add water-methanol injection for very hot weather conditions, or for those that run on race tracks, where both uses can over-whelm the stock intercoolers and need a little more help.
So where are we at?
I think we’ve got a much broader arsenal of power upgrades than what we thought, and we’ve probably got more questions than answers at the moment. I have been unable to get responses from an ECU re-map vendor on this board to basic questions, and they likely wouldn’t have the expertise to answer the more advanced ones. I’ve considered taking their standard re-map and customizing it on a local dyno using a professional tuner to make changes and monitor results. This week I contacted Viezu directly but they say they would need the car in Germany. They referred me to one of their vendors in the States.
A traditional method of tuning an engine has been to replace the entire ECU with an after-market unit that is fully programmable. Professional tuners start with a base map that will allow the engine to run and then tune it completely on the dyno. Every engine mod you can imagine can be installed, and every facet of the tune can be optimized, and monster power can be made. But that’s not available to us…just a download through the OBD port…maybe tweaked a little to account for pulleys. Kept safe, but not optimized, and with no idea of how much improved it could be if tuned and monitored on the car.
I’m thinking a good approach may be to significantly increase boost with pulley upgrades, and provide complete detonation protection by retaining the conservatively tuned ECU mapping, use only premium fuel, and use water-injection to combat higher IAT’s from the higher boost, increase air density, and lower in-cylinder combustion temps. Tuning would be optimized by varying the amount injected by interchanging nozzle flow rates, and detonation, AFR, IAT and power would be monitored on the dyno with a professional tuner. Regular windshield washer is available with different amounts of methanol mixes, winter grades being highest, and that affects the air-fuel ratio.
The injection pumps are triggered by a boost pressure switch which is adjustable. I’d have it activate under only full boost application, which is the only time it would be required to provide detonation protection, and this would minimize its operation and the amount of fluid consumed. I’ve used water injection on an MR2 Turbo dedicated track car for several years. I raised its 2 liter power from 200 hp to around 330 hp by installed a larger turbo, larger intercooler, removed catalytic converter and opened up exhaust system, raised boost from 10 psi to 17, and had the ECU tuned for all that. I’ve run it under the most gruelling track conditions for up to 2 hours at a time (PCA Enduros), and it’s been dead reliable.
I think you’d be hard pressed to find anyone that wouldn’t agree that the Jaguar 5L S/C couldn’t increase boost from 10.2 psi to 15-17 psi safely if the tune were sound, and if that were within spec for the supercharger. I would expect over 600 hp.
Hopefully those with technical insights will add to the conversation, and maybe someone will step up to try out some theories!
Bruce
The purpose of this thread is to provide an understanding of the power upgrade options, and the safety concerns that some members may have. Hopefully this will facilitate a discussion that will help in selecting the upgrade path that leads to your own Holy Grail of performance.
I won’t be explaining how the internal combustion engine works, but rather the specific factors related to modifying both normally aspirated and super-charged engines. This will make for an easier read that will move along quicker, and focus on what we need to know. I hope others will chime in and add to the discussion.
Let’s start with the basics, and discuss the #1 safety concern when tuning for more power…
Detonation
Also known as pre-ignition or knock, this is when the air-fuel mixture in the combustion chamber “pre-ignites” before the ECU generates its well-timed spark at the plug. This early combustion applies an opposing force to the movement of the piston which can cause damage to the piston ring-lands that hold the rings in place. You may hear a “pinging” noise, or more likely feel it as loss of power as the engine’s knock sensor detects it and the ECU responds by reducing engine power gently, or abruptly in more severe cases of detonation.
Factors that cause detonation individually, or in combination with others, include inadequate fuel octane, too lean an air/fuel ratio, too advanced ignition timing, too much boost, and too high air density. Each of these factors affects engine power, and tuners use them to increase power as much as possible. When done carefully they can provide safe power, but it can also be said that everything that produces power moves you closer to the threshold of detonation, and Jaguar will have been obsessively careful to set up the engine in the factory to avoid catastrophic engine failure at all costs, and under the most extreme operating conditions imaginable. Not so coincidentally, but these are the factors available to us to evaluate for our specific uses, and to see where we can modify to make power gains without sacrificing safety.
Let’s look at these factors individually…
Octane Level
Octane is the measurement of the fuels resistance to burn, with 91 (premium) having a higher resistance to burn than 89 and 87 (regular), and the greatest resistance to pre-ignition. Premium is specified for these engines, but the manufacturer knows that there are a number of reasons that fuel of insufficient octane and quality may end up being used on occasion, and will have likely set-up the engine conservatively enough to handle low octane without catastrophic engine damage. The engine’s knock sensor would likely detect the poor fuel octane and adjust engine operation and power output to cope with that.
Why do we care about octane levels? Because higher octane fuel allows the ECU tune to be “mapped” to run a leaner air/fuel ratio and/or a more advanced ignition timing map…and both will allow the engine to make more power! There will be a pretty significant factory safety margin there to be tapped into by the diligent enthusiast, and that’s exactly what ECU “chipping” or re-tuning does. Now consider how the ECU could be tuned if we ran even higher octane! See ECU Tuning below.
Air-Fuel Ratio
A lean mixture that contains higher ratios of air will make more power than a richer mixture. An air-fuel ratio of 14.5 parts of air to one part fuel (14.5:1 AFR) is about ideal for best fuel economy for cruising, but too lean to avoid detonation under hard acceleration. An AFR of 13.0:1 would make more power than a richer 10.0:1 would make. Lean AFR’s burn hotter, rich burn cooler, and that affects combustion chamber temperatures… and that has a direct bearing on the likelihood of engine detonation and/or engine wear. The ECU is programmed with AFR maps, which is a table of values covering all engine operating conditions from idle to redline rpm, light load to full throttle and boost. See ECU Tuning, and reducing combustion chamber temperatures below.
Ignition Timing
The ECU contains ignition maps that determine the precise moment that the spark plug will fire to ignite the air/fuel mixture in the combustion chamber under all operating conditions. Since it takes a moment for the mixture to fully combust, the spark plug fires as the piston is still rising, and just before top dead center. The combustion then forces the piston down on its power stroke and generates the power that turns the wheels. The most power can be made from this combustion if it’s ideally timed to apply maximum force to push the piston down on its power stroke. So the objective in tuning for increased power is to advance that ignition as much as possible without full combustion taking place when the piston is still moving upwards. If that were to happen it could cause serious damage. See ECU Tuning below.
Boost from Supercharger
Super-charged engines make more power because they force more air volume (called Mass Airflow) into the combustion chamber than a normally aspirated engine drawing air in at only atmospheric pressure. The ECU injects more fuel to create whatever the desired air/fuel ratio is. When more air and fuel combust, they do so with more energy, and the engine makes more power. So it follows that maximizing the amount of air through the engine is one goal in maximizing power. I’m told the super-charger on the 5L forces in extra air at 10.2 psi of pressure above atmospheric. Changing the diameter of the pulley that drives the super-charger will increase the boost pressure to force in more air and make more power. After-market pulleys are available upgrades that commonly add 1.5, 2.5 or 3 pounds of boost pressure. Increasing boost also increases intake air temps unfortunately, and that’s discussed in ECU Tuning below.
Air Density
The density of the air is also important because higher density air contains more oxygen particles that make more power than low density air. You may have noticed your engine makes more power on cooler days, and that’s because cold air is denser. Forcing air into the engine with pressure causes the Intake Air Temperature (IAT) to increase, loosing density, so they use intercoolers to reduce the IAT’s to increase density. Our engines have a pair of air-to-water intercoolers, but when ambient air temps are hot in the summer, or when the engine has been run hard for an extended period of time, the intercooler loses its effectiveness and the intake air density lowers, and engine power along with it. If we can increase the effectiveness of the intercooling we can make more power. See intercooling upgrades.
ECU Tuning
We discussed how running as lean an AFR as possible, without causing detonation, would make more power. And the same with running as much ignition advance as possible. The factory has programmed the ECU with values for both that will be safe if the user uses poor quality gas under extreme conditions for warranty purposes. If a knowledgeable enthusiast was dedicated to running only premium octane gas then his ECU could be re-mapped a little more aggressively to make more power and still be just as safe as the car driven on lesser grader fuel. If he ran “race” fuel (high octane) he could have that ECU tuned much more aggressively. Or he could raise octane by using water/methanol injection and tune more aggressively.
Water/Methanol Injection
Water and/or methanol is sprayed into the intake airstream through a nozzle, and plumbed back to a reservoir with a pump that is activated at some level of boost. It sometimes shares use of the windshield washer reservoir. As the fluid is injected it mixes with the intake air. Some vaporizes, and as it changes state from fluid to gas heat is absorbed, lowering air temps…and increasing air density. Some water droplets aren’t vaporized, and make their way into the combustion chamber where they lower intake air temps. Both of these can be positives if accounted for in the ECU tune.
High Flow Catalytic Converters and Cat-Back Exhaust Systems
Volumetric effficiency (VE) is a measure of an engine's ability to ingest airflow at any given pressure. Any method of improving VE will make more power across the entire powerband on a supercharged engine. The easiest way to do that is to reduce exhaust restrictions, with the catalytic converters probably being the largest restiction, and the rest of the exhaust system being the next. Extra power is made on the XKR-S by improving both. Cats are required by law, but some "high flow" cats may have the required C.A.R.B. approval and can be used. I've removed the cats from two other sports cars that I use on the track...and it made a huge difference. I suspect the stock resonators and mufflers with the active by-pass are probably pretty good, but there's bound to be a few ponies available, and it may be worth it to you just for the increased exhaust snarles.
ECU Re-mapping
Viezu (Germany) is a major supplier of ECU re- maps for the after-market industry, and they supply several vendors…if not all of them. Claims may vary slightly from one vendor to another, but the differences you would see between various dyno results will be from the differing types of dyno’s used, and normal individual engine power variations.
The standard ECU re-map offered will run slightly leaner air-fuel maps, and slightly more advanced ignition. Both can provide slightly improved throttle response. It’s programmed into the ECU by computer download through the OBD port under the dash. Gains are advertised as around 50 hp for the 5L S/C engines, and more fully require the use of premium octane fuel to make those gains, and provide protection from detonation. They also remove the 155 mph factory speed limiter…for those that find that too restrictive!
Whether that standard ECU re-map could safely handle additional boost from a pulley up-grade is unknown, although a vendor on JF claims to make an adjustment for that, and claims an overall power gain of around 85 hp. They likely dial back the fuel and ignition maps to avoid detonation. Now what if we ran higher octane to ward off detonation instead of dialling back the maps…more power gains would result! And if we increased octane by using water-methanol injection we’d increase power more by increasing air density! Maybe the standard ECU re-map is all we need…or maybe we don’t need a re-map at all….
What if instead of a re-map we took advantage of the conservative AFR and ignition by adding minimum 2.5 psi boost with a pulley upgrade. The stock map and decent gas should protect adequately against detonation. The richer fuel mixture also has the effect of reducing in-cylinder combustion temps.
How about running a 3 lb upper pulley, or maybe do the lower pulley also for even higher boost? Add water-methanol injection for very hot weather conditions, or for those that run on race tracks, where both uses can over-whelm the stock intercoolers and need a little more help.
So where are we at?
I think we’ve got a much broader arsenal of power upgrades than what we thought, and we’ve probably got more questions than answers at the moment. I have been unable to get responses from an ECU re-map vendor on this board to basic questions, and they likely wouldn’t have the expertise to answer the more advanced ones. I’ve considered taking their standard re-map and customizing it on a local dyno using a professional tuner to make changes and monitor results. This week I contacted Viezu directly but they say they would need the car in Germany. They referred me to one of their vendors in the States.
A traditional method of tuning an engine has been to replace the entire ECU with an after-market unit that is fully programmable. Professional tuners start with a base map that will allow the engine to run and then tune it completely on the dyno. Every engine mod you can imagine can be installed, and every facet of the tune can be optimized, and monster power can be made. But that’s not available to us…just a download through the OBD port…maybe tweaked a little to account for pulleys. Kept safe, but not optimized, and with no idea of how much improved it could be if tuned and monitored on the car.
I’m thinking a good approach may be to significantly increase boost with pulley upgrades, and provide complete detonation protection by retaining the conservatively tuned ECU mapping, use only premium fuel, and use water-injection to combat higher IAT’s from the higher boost, increase air density, and lower in-cylinder combustion temps. Tuning would be optimized by varying the amount injected by interchanging nozzle flow rates, and detonation, AFR, IAT and power would be monitored on the dyno with a professional tuner. Regular windshield washer is available with different amounts of methanol mixes, winter grades being highest, and that affects the air-fuel ratio.
The injection pumps are triggered by a boost pressure switch which is adjustable. I’d have it activate under only full boost application, which is the only time it would be required to provide detonation protection, and this would minimize its operation and the amount of fluid consumed. I’ve used water injection on an MR2 Turbo dedicated track car for several years. I raised its 2 liter power from 200 hp to around 330 hp by installed a larger turbo, larger intercooler, removed catalytic converter and opened up exhaust system, raised boost from 10 psi to 17, and had the ECU tuned for all that. I’ve run it under the most gruelling track conditions for up to 2 hours at a time (PCA Enduros), and it’s been dead reliable.
I think you’d be hard pressed to find anyone that wouldn’t agree that the Jaguar 5L S/C couldn’t increase boost from 10.2 psi to 15-17 psi safely if the tune were sound, and if that were within spec for the supercharger. I would expect over 600 hp.
Hopefully those with technical insights will add to the conversation, and maybe someone will step up to try out some theories!
Bruce
Last edited by Bruce H.; 05-26-2012 at 12:01 PM.
The following 3 users liked this post by Bruce H.:
#2
05-26-2012, 09:31 AM
Veteran Member
A lot of really good info.
So, to start, a very safe and simple upgrade is a smaller SC pulley - and the info you present jives completely with this, and many have already done the pulley.
I think a natural progression from the info you present would be to create specific scenarios/use cases that spell out exact combinations of upgrades and specific results. You presented questions for for certain combinations. These would be the specific scenarios/combos to work out for specific results. These scenarios could be spelled out/refined for minimum power upgrades/packages and evolve through specific combinations of successively more aggressive upgrades to higher power packages. Then we just follow the recipe for the level of power upgrade we feel most comfortable with.
Some basic ones are obviously:
1.5lb pulley upgrade, no ECU tune, no exhaust upgrade = (?)25bhp increase.
2.5lb pulley upgrade, no ECU tune, no exhaust upgrade = (?)bhp
3lb pulley upgrade, no ECU tune, no exhaust upgrade = (?)bhp
1.5lb pulley upgrade, no ECU tune, exhaust upgrade (brand?) = (?)40bhp increase.
And so on that maps out all the specific scenarios that are possible.
Would this be of value at all?
So, to start, a very safe and simple upgrade is a smaller SC pulley - and the info you present jives completely with this, and many have already done the pulley.
I think a natural progression from the info you present would be to create specific scenarios/use cases that spell out exact combinations of upgrades and specific results. You presented questions for for certain combinations. These would be the specific scenarios/combos to work out for specific results. These scenarios could be spelled out/refined for minimum power upgrades/packages and evolve through specific combinations of successively more aggressive upgrades to higher power packages. Then we just follow the recipe for the level of power upgrade we feel most comfortable with.
Some basic ones are obviously:
1.5lb pulley upgrade, no ECU tune, no exhaust upgrade = (?)25bhp increase.
2.5lb pulley upgrade, no ECU tune, no exhaust upgrade = (?)bhp
3lb pulley upgrade, no ECU tune, no exhaust upgrade = (?)bhp
1.5lb pulley upgrade, no ECU tune, exhaust upgrade (brand?) = (?)40bhp increase.
And so on that maps out all the specific scenarios that are possible.
Would this be of value at all?
#3
05-26-2012, 12:43 PM
I just edited the original post to include exhaust mods.
I'd like to start by finding some power data related to any of these mods. BigCat09 just installed the 2.5 psi Mina pulley on his XFR but didn't do a before and after dyno...without that we just have subjective feedback. An XJ S/C has a before and after dyno of his ECU re-map, but it wasn't done in a way that you can quantify the power improvement very well. So we need to discuss how to do a before and after dyno so useful data can be collected for:
- stock cats to high flow cats
- stock cat back exhaust (mid and rear section) to higher flow Mina, etc
- stock pulley to higher boost pulleys
- stock ECU map to ECU re-map with any other combo of mods
- addition of water injection...although this is more a mod to control detonation from other mods like higher boost as opposed to making power by itself
If I were to mod mine I'd likely go the high-flow cat (or no cats) mod, but retain the rest of the stock exhaust, and combine a high boost pulley with the stock ECU and 91 octane, and use water-injection just for track use (and really hot weather) to control IAT's while boosting non-stop on the race track. The power increase would be whatever it would be, and engine safety would never be a concern. If the dealer upgraded the ECU I wouldn't lose a re-map, and wouldn't be at the mercy of the dealer to provide a re-flash. If the dealer had an issue with the higher boost pulley it would be no different than my other cars that are modded to run much higher boost than stock.
Actually, I would never consider an ECU re-map unless I found a local dealer who could install it, and make re-flashes available, and would have to trust that he will still be around when/if I need it redone later. So far I have been unable to find that dealer...but I am hopeful!
Bruce
I'd like to start by finding some power data related to any of these mods. BigCat09 just installed the 2.5 psi Mina pulley on his XFR but didn't do a before and after dyno...without that we just have subjective feedback. An XJ S/C has a before and after dyno of his ECU re-map, but it wasn't done in a way that you can quantify the power improvement very well. So we need to discuss how to do a before and after dyno so useful data can be collected for:
- stock cats to high flow cats
- stock cat back exhaust (mid and rear section) to higher flow Mina, etc
- stock pulley to higher boost pulleys
- stock ECU map to ECU re-map with any other combo of mods
- addition of water injection...although this is more a mod to control detonation from other mods like higher boost as opposed to making power by itself
If I were to mod mine I'd likely go the high-flow cat (or no cats) mod, but retain the rest of the stock exhaust, and combine a high boost pulley with the stock ECU and 91 octane, and use water-injection just for track use (and really hot weather) to control IAT's while boosting non-stop on the race track. The power increase would be whatever it would be, and engine safety would never be a concern. If the dealer upgraded the ECU I wouldn't lose a re-map, and wouldn't be at the mercy of the dealer to provide a re-flash. If the dealer had an issue with the higher boost pulley it would be no different than my other cars that are modded to run much higher boost than stock.
Actually, I would never consider an ECU re-map unless I found a local dealer who could install it, and make re-flashes available, and would have to trust that he will still be around when/if I need it redone later. So far I have been unable to find that dealer...but I am hopeful!
Bruce
Last edited by Bruce H.; 05-27-2012 at 05:48 AM.
#5
05-26-2012, 06:06 PM
Veteran Member
Great job Bruce for putting all this info into a single post. I think you pretty much covered most possibilities very well.
Let me suggest one that you did not mention; changing the rear-end ratio from the present 3.31 to something like 3.7 - 3.9. That would make probably more difference in the acceleration and all around street/track performance than most others combined. All that while keeping things perfectly legal, factory boost, smog etc. Not sure if anyone makes those gears, if not, they should. Drawback would be that the cruising RPMs would be slightly higher, increasing fuel use somewhat and the odometer would have to be reprogrammed.
Also, I would be a bit hesitant running 15-17 psi boost on pump gas with the XKR's fairly high compression ratio. I generally don't go over 13-14 psi with my twin turbo on 91 octane gas and I use an air/fuel gauge to constantly monitor my ratio. I go to 19 psi max at a self-programmed air/fuel ratio of 10.5:1 at 8000 RPM but, only if using 103 octane racing fuel.
I like the idea of a pulley upgrade. That will give modest low and high end power gains with really no deleterious effects.
Upgrading the exhaust is generally great for performance but, should only be done by performance drivers who are not afraid to shift near redline. Opened exhausts do very little if one drives in the 2 - 3K RPMs. I once knew a driver who was bragging with having 500+hp, yet, he was ALWAYS shifting near 3000 RPM. I pointed out to him that he REALLY had only about 125 hp for his method of driving. He called BS on me until I produced a dyno sheet showing very little power in that RPM range and 500 hp at 8000 RPM, which he never, ever even approached.
Alcohol/water injection works by all accounts in allowing even radical boost levels. I have seen people using nearly 30 psi boost (and even higher) with such applications. I, at one time, purchased most of the components for the injection but, never installed it. Too much hassle for a street car to have an additional "fuel tank" to locate and keep track of, and the penalty would be instant engine damage if something (pump, line, injector, mixture runs out) failed to operate during high boost conditions.
I must be getting really old to say that, IMO, the XKR has already more than enough power. I'd be surprised if 2 percent of the XKR owners used it fully at more than 1 percent of driving time. But, hey, I remember a few years ago when my motto was; "You can NEVER have enough power"
For people, like that, your contribution could prove quite valuable.
Albert
Let me suggest one that you did not mention; changing the rear-end ratio from the present 3.31 to something like 3.7 - 3.9. That would make probably more difference in the acceleration and all around street/track performance than most others combined. All that while keeping things perfectly legal, factory boost, smog etc. Not sure if anyone makes those gears, if not, they should. Drawback would be that the cruising RPMs would be slightly higher, increasing fuel use somewhat and the odometer would have to be reprogrammed.
Also, I would be a bit hesitant running 15-17 psi boost on pump gas with the XKR's fairly high compression ratio. I generally don't go over 13-14 psi with my twin turbo on 91 octane gas and I use an air/fuel gauge to constantly monitor my ratio. I go to 19 psi max at a self-programmed air/fuel ratio of 10.5:1 at 8000 RPM but, only if using 103 octane racing fuel.
I like the idea of a pulley upgrade. That will give modest low and high end power gains with really no deleterious effects.
Upgrading the exhaust is generally great for performance but, should only be done by performance drivers who are not afraid to shift near redline. Opened exhausts do very little if one drives in the 2 - 3K RPMs. I once knew a driver who was bragging with having 500+hp, yet, he was ALWAYS shifting near 3000 RPM. I pointed out to him that he REALLY had only about 125 hp for his method of driving. He called BS on me until I produced a dyno sheet showing very little power in that RPM range and 500 hp at 8000 RPM, which he never, ever even approached.
Alcohol/water injection works by all accounts in allowing even radical boost levels. I have seen people using nearly 30 psi boost (and even higher) with such applications. I, at one time, purchased most of the components for the injection but, never installed it. Too much hassle for a street car to have an additional "fuel tank" to locate and keep track of, and the penalty would be instant engine damage if something (pump, line, injector, mixture runs out) failed to operate during high boost conditions.
I must be getting really old to say that, IMO, the XKR has already more than enough power. I'd be surprised if 2 percent of the XKR owners used it fully at more than 1 percent of driving time. But, hey, I remember a few years ago when my motto was; "You can NEVER have enough power"
For people, like that, your contribution could prove quite valuable.Albert
Last edited by axr6; 05-26-2012 at 11:13 PM.
#7
05-27-2012, 01:44 AM
Veteran Member
Trending Topics
#8
05-27-2012, 06:38 AM
Great job Bruce for putting all this info into a single post. I think you pretty much covered most possibilities very well.
I must be getting really old to say that, IMO, the XKR has already more than enough power. I'd be surprised if 2 percent of the XKR owners used it fully at more than 1 percent of driving time. But, hey, I remember a few years ago when my motto was; "You can NEVER have enough power" For people, like that, your contribution could prove quite valuable.
Albert
I must be getting really old to say that, IMO, the XKR has already more than enough power. I'd be surprised if 2 percent of the XKR owners used it fully at more than 1 percent of driving time. But, hey, I remember a few years ago when my motto was; "You can NEVER have enough power"
For people, like that, your contribution could prove quite valuable.Albert
I'd like to know more about our superchargers ability to increase boost at high rpm. It may be that boost increases from pulleys falls off as rpm increases and the S/C runs out of breath. This may be one reason why Jaguar opened up the exhaust on the XKR-S rather than increasing boost...and maybe not. And if doing one or the other is good, then doing both would naturally be much better!
Bruce
#9
05-27-2012, 06:49 AM
Jaguar Supercharger Upgrade | Jaguar Supercharger.
Does anyone know which model of Eaton supercharger is on the 5L XKR? The above site discusses the M112 running out of breath at higher rpm.
Bruce
#10
05-27-2012, 07:38 AM
Veteran Member
With my car I also make use of the reserves build into the ECU, which is why I haven’t needed any tuning on that area, it is now as sharp as it can be even.
I think something similar will also count for the 5.0 cars, and I hope no know a bit more in the coming time.
There are some heavy torque reductions build into the ECU, so just lifting that will already add about 40 hp or so, and lots of midrange torque. Then you still have a little room to play with, i.e. speeding up the supercharger.
Ideally a larger lower pulley would be good, but that one should be made very well so it retains the right damping properties. Haven't worked yet with the upper pulleys from a new 5.0 car, so don't know yet what the smallest is you can go.
600hp shouldn’t be too hard the TVS unit (it is so much more efficient than the older Eaton roots ones), maybe an exhaust update might be needed for that, can’t tell. On my car I am still using the stock exhaust (but with sports catalysts), and don’t think the 5.0 one is more restrictive.
I think something similar will also count for the 5.0 cars, and I hope no know a bit more in the coming time.
There are some heavy torque reductions build into the ECU, so just lifting that will already add about 40 hp or so, and lots of midrange torque. Then you still have a little room to play with, i.e. speeding up the supercharger.
Ideally a larger lower pulley would be good, but that one should be made very well so it retains the right damping properties. Haven't worked yet with the upper pulleys from a new 5.0 car, so don't know yet what the smallest is you can go.
600hp shouldn’t be too hard the TVS unit (it is so much more efficient than the older Eaton roots ones), maybe an exhaust update might be needed for that, can’t tell. On my car I am still using the stock exhaust (but with sports catalysts), and don’t think the 5.0 one is more restrictive.
#11
05-27-2012, 08:22 AM
Thanks, Avos. Can you discuss what the torque limiters are?
I just found your thread with dyno in the other forum...very impressive!
https://www.jaguarforums.com/forum/x...-631-hp-72977/
Bruce
I just found your thread with dyno in the other forum...very impressive!
https://www.jaguarforums.com/forum/x...-631-hp-72977/
Bruce
#12
05-27-2012, 08:43 AM
Veteran Member
Jaguar has limited the amount of torque the engine is allowed to generate in the ECU (which is why you see a flat torque line at midrange), iirc it had primarily to do with saving the gearbox/torque converter. The latter is reported to have been strengthened, which is probably why some of the torque limiters have been lifted for that version, but i don't have any further details about that.
#13
05-27-2012, 11:42 AM
#14
06-01-2012, 09:11 PM
Senior Member
Nice thread...Bruce, I can certainly see all the years of Supra ownership coming through in this thread!
Well, I just got the Mina pulley installed along with an ECU tune. As you know, I hit the track bone stock and trapped 116mph.
Went back, also on normal street tires and .... trapped exactly the same. Granted, traction limited, but still. Supposedly the ECU needs miles on it after the flash and pulley to "learn" and really let the power out. We'll see.
The car "feels" faster from a rolling hit. I can see the trac light flash from time to time if I floor it at 50mph - it's a pretty violent pull.
So, I am going to beat the hell out of it for the next week or two while I wait on some drag radials that actually fit. Then back to the track so I can leave WOT and see what's up. Seriously, the car should trap 120 easy.
Stay tuned....
Jay
Well, I just got the Mina pulley installed along with an ECU tune. As you know, I hit the track bone stock and trapped 116mph.
Went back, also on normal street tires and .... trapped exactly the same. Granted, traction limited, but still. Supposedly the ECU needs miles on it after the flash and pulley to "learn" and really let the power out. We'll see.
The car "feels" faster from a rolling hit. I can see the trac light flash from time to time if I floor it at 50mph - it's a pretty violent pull.
So, I am going to beat the hell out of it for the next week or two while I wait on some drag radials that actually fit. Then back to the track so I can leave WOT and see what's up. Seriously, the car should trap 120 easy.
Stay tuned....
Jay
#15
06-02-2012, 01:20 AM
Thanks Jay. It was routine to make similar peak power levels on the Supra from just a 3L engine as the Jag's stock 5L S/C, but the extra low rpm torque from another 2L displacement and lower rpm boost from the S/C feels vastly superior on both the road, and road course. There really is "no replacement for displacement".
Maybe you could tell us about the pulley install, and details of the ECU tune. Was the hood removed and old pulley pulled or cut off?
Bruce
Maybe you could tell us about the pulley install, and details of the ECU tune. Was the hood removed and old pulley pulled or cut off?
Bruce
#16
06-02-2012, 08:13 AM
Did the possibility of voiding the manufacturer's warranty enter into your decision for these mods?
Mike
#17
06-02-2012, 09:28 AM
Senior Member
Hey guys -
The install was done at Broadway Performance here in NJ, the old pulley was pulled off, not cut. I can't really speak to the details on the install, i.e. difficulty level, etc...just that it was a quite a few hours. However, the guys at Mina were helpful and generally available during the whole process. Just like any other blower pulley swap.
ECU tune is, I'm assuming here, is holding the key to unlocking all the power these mods should allow. So, I'm giving it a proper amount of time to "learn", "get used to"...whatever. And then back to the track to pass final judgement
Yeah, warranty is always in the back of my mind. But should something go really, horrible away with the car - flashing back to stock is easy. And if I was really nervous, I'd swap the stock pulley back on.
Jay
The install was done at Broadway Performance here in NJ, the old pulley was pulled off, not cut. I can't really speak to the details on the install, i.e. difficulty level, etc...just that it was a quite a few hours. However, the guys at Mina were helpful and generally available during the whole process. Just like any other blower pulley swap.
ECU tune is, I'm assuming here, is holding the key to unlocking all the power these mods should allow. So, I'm giving it a proper amount of time to "learn", "get used to"...whatever. And then back to the track to pass final judgement
Yeah, warranty is always in the back of my mind. But should something go really, horrible away with the car - flashing back to stock is easy. And if I was really nervous, I'd swap the stock pulley back on.
Jay
#18
06-14-2012, 08:23 AM
Big thanks to BigCat09 who has just posted dyno results of his 5L S/C XFR with ECU tune, 1.5 lb pulley, intake filter and exhaust mods...
https://www.jaguarforums.com/forum/x...-review-75060/
Bruce
https://www.jaguarforums.com/forum/x...-review-75060/
Bruce
The following users liked this post:
BigCat09 (06-19-2012)
#19
06-19-2012, 01:28 PM
Veteran Member
Here is an update as I just revisted the dyno again.
https://www.jaguarforums.com/forum/x...d-today-75360/
https://www.jaguarforums.com/forum/x...d-today-75360/
The following users liked this post:
Bruce H. (06-20-2012)
#20
06-20-2012, 07:19 PM
You all have some serious ballz! I'd be TERRIFIED of voiding my Select Edition 100k warranty by swapping pulleys. Let alone installing software that MIGHT, despite protestations to the contrary, be detected and used as the basis for warranty denial.
I went down this route with a different manufacturer (MBZ) and different mod provider (who shall remain nameless). Total cluster f. Any excuse to deny ANY repairs were tied to the fact that it MUST have been the extra power from the pulley and ECU tune that caused the failure. Truth be damned, it was up to me to decide to cut my losses or to sue MBUSA. NOT a fun dilemma. I vowed never to mod a warrantied car again.
But the ECU only is tempting, given how much power seems ready to be tapped through reprogramming alone. Despite being once bitten, I'm starting to think that if I can flash back to stock and then re-flash the modded programming, risk seems minimal. These tuners offer (I believe) 2 re-flashes for free, then they start charging (not sure how much or what'd be involved flashing BACK to stock first). Getting there...
But to swap the pulley! That's courage, my friends. I envy your bravery and hope that the great Jaguar God is more merciful than the evil Teutonic overlords at MB. Lost me as a customer for life over a couple thousand bucks...
I'm trying to figure out how much of the gain we are discussing in this thread would apply to us 2010+ XKR owners who want to play the middle road and only do the ECU for fear of warranty compromise.
Keep the posts coming, y'all. The more successful installs, the closer I come to taking the (half) plunge. Would LOVE to do the pulley also, so much free and safe power, but just too easy to spot, and no sense of how severely Jaguar looks on this sort of thing. If they have a casual attitude towards a relatively mild mod like a small difference in pulley size, and we could count on them being laissez-faire, I shudder to think of the pleasure and value of so much extra power from doing the pulley and ECU together...
Thanks for all the info.
Skeeter
I went down this route with a different manufacturer (MBZ) and different mod provider (who shall remain nameless). Total cluster f. Any excuse to deny ANY repairs were tied to the fact that it MUST have been the extra power from the pulley and ECU tune that caused the failure. Truth be damned, it was up to me to decide to cut my losses or to sue MBUSA. NOT a fun dilemma. I vowed never to mod a warrantied car again.
But the ECU only is tempting, given how much power seems ready to be tapped through reprogramming alone. Despite being once bitten, I'm starting to think that if I can flash back to stock and then re-flash the modded programming, risk seems minimal. These tuners offer (I believe) 2 re-flashes for free, then they start charging (not sure how much or what'd be involved flashing BACK to stock first). Getting there...
But to swap the pulley! That's courage, my friends. I envy your bravery and hope that the great Jaguar God is more merciful than the evil Teutonic overlords at MB. Lost me as a customer for life over a couple thousand bucks...
I'm trying to figure out how much of the gain we are discussing in this thread would apply to us 2010+ XKR owners who want to play the middle road and only do the ECU for fear of warranty compromise.
Keep the posts coming, y'all. The more successful installs, the closer I come to taking the (half) plunge. Would LOVE to do the pulley also, so much free and safe power, but just too easy to spot, and no sense of how severely Jaguar looks on this sort of thing. If they have a casual attitude towards a relatively mild mod like a small difference in pulley size, and we could count on them being laissez-faire, I shudder to think of the pleasure and value of so much extra power from doing the pulley and ECU together...
Thanks for all the info.
Skeeter
Last edited by Skeeter; 06-20-2012 at 07:25 PM.