Hi there,
My name is Matt, I've been a member since quite some time, but this is my first post. I saw that even though several vendors offered ECU tunes, there wasn't a single dyno I could find of the ECU gains (only ones I found were ECU + exhaust, or ECU + pulley....). So I got a tune, did a dyno run before, one after, I hope many of you will find this helpful!

Results are:
HP: 291.1 before, 317.8 after, @ ~6000rpm
Nm: 431 before, 452 after, @ ~4000rpm (I thought maximum value would be at 3500...)

Well good news is that the gain is almost 27 whp, that's almost 34 chp
Torque-wise, it's not that impressive, only 21 wNm, or 26 at the engine.
I've attached the dyno sheet, the guy who did the tuning said the AFR was waay rich in the higher rpm range, so that's where the most gains would be had, that explains the disparity between the large hp gain vs the small torque gain.

Now what I want to ask you guys is, doesn't 291hp sound a bit low for stock? I admit temps were a bit high, 25-30 degrees, and the calibration runs got the car a little heat-soaked (but I waited about 1/2hr with the engine off to get it to cool down a bit, went from 283hp to 291). Dyno was an awd Mustang 500, twin rollers. I've heard that if you run it in 3rd you get different results versus running in 4th, is it true? Did any of you make a run in both, to see if there is a difference? I was expecting ~320whp, so 30whp under that is not making me very happy... Any ideas?

Well anyway, I hope this helps! I got a pulley (and the white plastic dummy), but realized I have to take out the expansion tank (that means bleeding the cooling system, getting under the car etc.), any advice for a beginner on how to do the pulley change & supercharger snout grinding, would be very welcome!

Have a great day!

 

Welcome to the forum Mat. You should also stop by our New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum and introduce yourself there too.

Well that is a serious gain from an ECU remap! Very nice! Who did it?

Maybe have a look at my thread https://www.jaguarforums.com/forum/x...-my-xjr-96325/ as a reference for your dyno questions.

I see in your pic you ran with the bonnet open, my car made 20HP less with the bonnet up!

291 is maybe a little down for stock (or maybe not? how many kms on the car?). But don't forget all dynos give different results, it's not really possible to compare results that closely, the most valuable thing to see is gains from a baseline, which you did.

Yes you can get slightly different results from running in 3rd or 4th. Most dynos will run in 3rd because they have a speed limitation. Redline in 4th in our cars is ~250km/h. Not all dynos can read that fast. My runs were done in 3rd.

You'll get there with the pulley installation. Just plan it out. Take your time.

 

Wow, thanks for posting this. Like Cambo already asked, who did it and where are you located (sounds like UK or EU?)? Was this a canned tune, or a live tuning session?

Looks like the redline needs to be bumped up a couple of hundred RPM as your power is very flat and not dropping off.

Great post and nice car!

 

Hey there guys! Sorry for taking so long to reply, I'm on a well-earned & recharging vacation right now, after Transylvania & Bucovina, we're just about to head to the Danube delta!
To answer your questions, I went to Racing Code in Bucharest, Romania. The guy on the laptop, when asked, told me he read the original soft, advanced the timing mainly in the higher rpms, where the A/F was very rich, and one or two other things that I forgot. Then the car had another go (I took care to have the same conditions). Only thing that worried me was that he was adamant the drivetrain losses are NOT a percentage, but a value his dyno estimates, so if the car put down 291rwhp, it meant that it had 312 hp at the engine. I didn't say anything else other that this was the first time I have ever heard that. He said that it's a shame, but my car has 100hp less, and that the facts printed in the car's documents are a lie. He did many runs for 15 minutes in full load before measuring the car's hp, to calibrate the dyno & to measure the drivetrain losses - does anybody know what this procedure is? The losses calculated by the dyno were under 40hp. When I told him politely I find all that was said a little hard to believe, he took it kind of personal, so I didn't want to go on - I just wanted my +hp. But really, can somebody explain what is the whole "measure drivetrain losses on the dyno" thing?

Very interesting, Cambo, that the car can have a 20hp difference with the hood up/down! I've mashed my brains about this interesting finding, do you have a theory as to why it happens?

Anyway, when I get back I'm looking to getting another 1/4mi pass, at the same location & in the same conditions, that's where I can truly see the gains!

 

 

Taken from a vette forum:
Here's how I like to explain the difference. . .

DynoJets are inertia dynos, and have been around for years, much longer than any type of load cell dyno. Inertia dyno's work on the principle of the acceleration of a known mass over time. Their rollers are the known mass. Weighing in at over 2500lbs or so. Your car gets strapped down to the machine, and the dyno collects it's data. It is able to calculate horsepower by measuring the acceleration in rpm of the rollers in regards to RPM. This is why gearing can affect the dyno results, more on that in a bit. Now that the dyno has recorded the horsepower curve, it can take the integral of that curve and get the torque curve. Since the dyno’s power calculations are based on the acceleration of mass over time in regards to RPM, gearing is very important. Since a vehicle with a lower gear ratio can accelerate the mass to a higher speed using less engine RPM, it will show a higher horsepower number than a car with a higher gear ratio. If a car is able to accelerate the dyno’s rollers from 200rpm (roller) to 300rpm (roller)in 1500rpm (engine), then the dyno is going to record more power than a car that did that in 2000rpm (engine).

Now we go to Mustang dyno’s and other loaded dyno’s. Our Mustang MD-1100SE dyno’s rollers weigh 2560lbs. That is the actual mass of the rollers, much like the DynoJet. That’s about where all the similarities end. When we get a car on our dyno, we enter two constants for the dyno’s algorithms. One being the vehicle weight, the other being what’s called “Horsepower At 50mph”. This is a number that represents how much horsepower it takes for the vehicle to push the air to maintain 50mph. This is used as the aerodynamic force. Mustang dyno’s are also equipped with a eddy currant load cell. Think of a magnetic brake from a freight train. This magnetic brake can apply enough resistance to stall a big rig. Off one side of the eddy currant load cell, there is a cantilever with a 5volt reference load sensor (strain gage). As the rollers are spinning this load sensor is measuring the actual torque being applied. So as the rollers spin, the load sensor is measuring the force being applied, sending that information to the dyno computer, taking into account the two constants entered earlier, computing the amount of resistance needed to be applied to the rollers to load the car so that the force of the rollers resistance is as close to the force the car sees on the street. The dyno is then able to calculate the total force being applied to the rollers in torque, and then taking the derivative of that torque curve to arrive at the horsepower curve. Since torque is an actual force of nature, like gravity and electricity, it can be directly measured. Horsepower is an idea that was thought up by man, and cannot be directly measured, only calculated.

I like to state it like this. . . I start by asking how much your car weighs, lets say 3500lbs. Now you take your car and you make a make a WOT rip in your tallest non overdrive gear, how much mass is your engine working against? 3500lbs right? Now you strap your car on a DynoJet and you make a WOT in the same gear, how much mass is your engine working against? 2500lbs right? Now you strap your car on a Mustang dyno, how much mass is your engine working against? 2500lbs. Plus the resistance being applied by the eddy current generator. We’ve seen anywhere for 470lbs of resistance to over 700lbs of resistance as measured in PAU force in the data logs. So which one is more accurate? Well they their both accurate. If a DynoJet dyno says you made 460rwhp, then you made 460rwhp. If a Mustang dyno says you made 460rwhp, you also made 460rwhp. Now which one of those numbers best represents what your car is doing when its on the street. That’s a different question.

The most important thing to remember is that a dyno is a testing tool. If the numbers keep increasing, then you’re doing the right thing. We try to look over at NET gain, instead of Peak HP numbers. A 30rwhp increase is a 30rwhp increase regardless of what dyno it is on.

Now I can address how to calculate the difference between one type of dyno and another. Simply put, you can’t. Because Mustang dyno’s have so many more variables, it’s not a simple percentage difference. We’ve had cars that made 422rwhp on our Dyno, two days later make 458rwhp on a DynoJet the next day. We’ve also had cars that made 550rwhp on our dyno, make 650+rwhp on a DynoJet a few days later at another shops Dyno Day. For instance, my 2002 Z28 with a forged internal LS6 Heads/Cam/Intake, makes 460rwhp on our dyno. I thought that was a little low, since I’ve had cam only LS6 Z06 vettes make 450rwhp. So I overlaid the dyno graphs. Guess what, the PAU force for my car was almost 200lbs more than the C5Z06 that made 450rwhp with cam only. So I entered the weight and horsepower at 50 number for a C5Z06 and did another horsepower rip with my car. The only reason I did that was to compare Apples to Apples. This time my car made 490rwhp, no other changes. Now I don’t go around saying my car made 490rwhp, I say what it actually did with the correct information entered into the computer. It made 460rwhp. Now if I ever get a chance to take it on a DynoJet (which I plan to in the spring), I have no doubts it’ll be over 500rwhp. I know this based on airflow and fuel consumption on the data logs.

But since we’re asked this question constantly we're fairly conservative, and hence tell our customers that the difference is closer to 6-7%, but as you make more power, and the more your car weighs, the difference increases as well. You must remember, Dyno's regardless of the type are tuning tools, and are in no means meant to tell people how fast their car is. Now which one is more "real world" is a totally different question. I like to explain it like this..... If you drive your car in a situation in which you have no mass and you're in a vacuum, so basically if you do intergalactic racing in space, use a DynoJet. If your car sees gravity, and has an aerodynamic coefficient, and you race on a planet called Earth, then use a Mustang Dyno

 

less power with bonnet open is usual on modern cars : bonnet open on rolling bench means usually emission control ! so ECU apply leaner calibration to pass the test !

 

I'd like to see you produce some validation for that staement...

 

I believe the dieselgate scandal got all your "required" validation, many manufacturers admitting they were/are tricking the emission tests.

 

My XJR has 115,000 miles. Throws a bank 2 O2 sensor code on startup about once a year. Low voltage. Usually with a CAT code. Once cleared it is fine. Think original sensors.
With these running rich to begin with would new O2 sensors improve running?

 

So-called "lazy" O2s are worth replacing, yes. Buy decent new ones, not cheap Chinese knock-offs.

 

How do you know that you are buying decent new ones when they may well have originated in China, Japan, or Indonesia in the first place?

 

looks like all four Denso are under 300.00 USD. Unless I find cheaPer this is XMAS for me.

 

They are likely made in Indonesia at a Denso owned factory.

I have no problem with that.

 

Genuine parts tend to be OK. Non-genuine, well you may be lucky.