Well I have made my decision and have scheduled a Eurocharged Pulley and tune install in Houston.

Reasons:

- Close to Dallas
- Reputation
- cost ( Running a $650 pulley and tune special- https://www.jaguarforums.com/forum/v...%24ale-127404/ )

Since doing a before and after AWD dyno is onerous I have decided to measure performance in another and probably more accurate manner. I purchased a Vbox Sport and am currently measuring baseline acceleration. Time/distance, time/MPH range and acceleration G.
I'm making multiple runs in the same location with very close atmospheric conditions.

This should be a great way to validate performance improvements scientifically vs not just using the butt dyno. After all, I am not looking for a HP number to spout but for better mid range torque.

What I have discovered thus far is that this car is hard to launch well and consistently. (For me anyway) Wheel spin is controlled with throttle and if too much, you have blown that 0-60, 1/8 and 1/4 mile time. However, regardless of that, the times that remain very consistent are 30-70MPH, 50-70MPH, 60-130MPH and acceleration G.

The 60-130 metric is a great acceleration metric to compare to other vehicles and should improve significantly with the pulley and tune.

I'm scheduled for Oct 1st and should have some hard VBox Sport data as well as my impressions and opinion of the Eurocharged pulley and tune.

In the mean time, please standby:

Walt

 

Given the electronic limitation of the boost, why are you bothering with the pulley?

A map that hangs on to the boost and fuels to match will give you a lot more peak torque.

But, given that you can't get it to hook up as is, why do you need more?

It's like fitting 24,000lb thrust engines to your 707. If you try taking off at full power you'll rip the wings off...

 

Exciting stuff.

From what I understand going to the smaller pulley means you hit max boost lower in the rev range, which means more low/mid range power. At least that's what i've been told.

Walt, please try to get some dyno time, you know everyone will ask for the numbers anyhow

 

Looking forward. Agree, dyno numbers don't mean much except bragging rights. Really boils down to actual on street or track gains.

 

F-Typical-

"Given the electronic limitation of the boost, why are you bothering with the pulley?"

In order to have more available boost at a lower RPM. What exactly is the "electronic limitation of the boost" in my car? Can you point me to a document that quantifies it?


"A map that hangs on to the boost and fuels to match will give you a lot more peak torque."

May be getting that with the tune also.


"But, given that you can't get it to hook up as is, why do you need more?"

As I stated in my original post I am looking for more mid-range torque.


"It's like fitting 24,000lb thrust engines to your 707. If you try taking off at full power you'll rip the wings off..."

Then I would take off at the certificated 16,000 lb thrust rating and during the climb use the extra thrust available to offset the increase in density altitude. That would enable me to climb faster and to a higher altitude sooner unless I was wing limited.

Just out of curiosity, do you have a tune on your F Type?

Walt

 

I am less interested in horsepower and torque numbers that are very hard to accurately measure on a dyno and are susceptible to lots of errors including guesses as to drive train loss. What can be measured very accurately by each of us and is what we all are looking for is acceleration.
G-Acceleration as well as speed acceleration. That is a more day to day quantitative application. Forget Horsepower, forget car weight. When you punch the throttle, does the car throw you into the back of your seat and impress you with its ability to accelerate?

My 997 Turbo S sure does and the tune really woke it up. My Cayenne Turbo S sure does and the tune really woke it up. I'm betting that a Eurocharged pulley and tune will wake up my V8S. I sure hope so anyway.

Now I did before and after dynos of both Porsche's, but so what, I really don't care what the plotted numbers state. (both over 600HP for those that have to know) But what I care about is if you were to ride with me in either one of them and I was to punch the accelerator the words out of you mouth would be, "holy crap this this is &^%(*&^ FAST!) The V8S is almost there for me but not quite. That's why I want the pulley and tune.

Believe me I will know if the mods make a significant difference just from driving it but I'll be able to quantify it against my baseline V Box acceleration numbers.
30-70 MPH Real world driving
50-70 MPH Real world driving
60-130 MPH (Often used for acceleration comparisons but you probably do not get over 90MPH every day)

I really like the V8S but there is something wrong in my opinion when my wife can hang with me in the Cayenne!

Walt

 

The boost is controlled by the ECU, the bypass valve is used to bleed off boost to maintain a target value. So in fact the blower is always putting out higher boost, it's just bled off.

The XF/XK owners on this forum have measured between 7-11 PSI on their cars, depending on the tune in them.

Don't have the factory defined numbers but from what people have reported, the 510HP tune is around 7psi and the 550HP tune is around 9psi. The cars that have been tuned aftermarket have gone up to around 11psi, I would hope that the Eurocharged tune for you would be similar.

This method of limiting the boost in the 5.0L is different to the older 4.0L & 4.2L, with the old engines you just got the maximum boost mechanically, and it dropped away with altitude. With the 5.0L you get that max. boost regardless of your altitude, which is nice...

The 5.0L also runs higher static compression so the boost numbers are lower, you can't crank 15psi into them like the old engines.

 

Walt,

That Jaguar quote a fixed torque figure from 2500-5500rpm says they're limiting the boost across that Rev range. The torque curve on a supercharged engine should be a bell-shape rather than a plateau.

On the left, boost builds as the supercharger spins faster, on the right it tails off as the efficiency drops off (it takes more and more torque to spin the supercharger, which has already reached its maximum throughput).

A smaller pulley will move the peak to the left, but might not increase its height without getting some gas-flow work done on the supercharger and the inlet manifold.

In a boost controlled set up like the F-type, a smaller pulley will give you more torque below 2500rpm (do you really care though?), but might not give you any more above 5500rpm.

Hence my comment about making the most of the boost your supercharger can already produce, rather than fitting a smaller pulley.

HTH

 

HTH,

I'm reading "might not" statements in your response. Hardly definitive.

Here is my counter, 5 tuners I have either spoken with all make and recommend the smaller pulley. (Simply up selling?) I have had discussions with 2 end users that have the smaller pulley and tune and say the overall performance change is significant.
I've seen a couple before/after dyno plots from vehicles that have the smaller pulley and tune and in both cases the after vs before torque plot was significantly higher across the RPM band all the way to redline.

Obviously for more power the boost level is raised. Whether it could be raised enough by simply closing the electronic bleed valve or a combination of that and the inclusion of the extra boost provided by the smaller pulley, I have no idea. But it does not sound like you do either. I would really love to hear from a true expert knowledgeable in this endeavor. I wish there were more data points to make an educated decision with.

I also have questions across the board with something in pretty much everybody's statements concerning this subject.

Take Cambo's quote here. "The boost is controlled by the ECU, the bypass valve is used to bleed off boost to maintain a target value. So in fact the blower is always putting out higher boost, it's just bled off."

I'll buy the first statement but not the second "always" statement. Is boost being bled off at 1,000 RPM? What about 1,500 RPM?, 2,000 RPM, 2500? At what point is the SC building excessive boost that needs bled off? When is the bled off valve programed to start opening? is it ever fully open? What is the boost provided by the SC at all the different RPM?

You asked, "In a boost controlled set up like the F-type, a smaller pulley will give you more torque below 2500rpm (do you really care though?)"

Sure I care, every little bit helps. On my turbo S I can start feeling the torque come into play right around 2,000 RPM. Sure a different animal but I'm certainly good with more boost/torque at the lower RPM ranges.

As I mentioned before these are pretty good real world driving performance metrics to time:

30-70 MPH Real world driving
50-70 MPH Real world driving
60-130 MPH (Often used for acceleration comparisons but you probably do not get over 90MPH every day)

If I can significantly decrease the times in these spreads I will be very happy.

What I seem to read about are the guys that have done the smaller pulley and tune say it has transformed the car and they have no regrets. On the other side I have read threads from guys that have not done a pulley and tune but that have their own ideas and preceptions as to what might or might not happen.

Bottom line: I'll be a great test case since I had done great before pulley and tune baseline time/distance acceleration testing up to 130MPH. Once the mods are in place and I have given the ECU plenty of time to adapt, I'll display them here.

For anyone that has "facts" on anything related to this thread I would love to hear them.

Walt


"but might not increase its height without getting some gas-flow work done on the supercharger and the inlet manifold." But then again, it might.
"but might not give you any more above 5500rpm." But then again, it might.

 

You've decided you want to do it, so the above should provide you with some extra topics to question your potential suppliers on.

The ECU is definitely limiting boost from 2500-5500rpm based on the stated torque figures for the car. There may be some additional limitation either side of that to smooth things out.

Better?

 

With a reputable tuner, a pulley swap will always be accompanied by an ECU remap, because without the remap you risk some serious damage to the engine through incorrect fuel/air ratio or thermal damage.
A torque plot typically has 3 stages: the gain (or slope) where torque increases from 0 to the torque limit, the tabletop where the power is maxed out and excess pressure is bled off, and the dropoff where the supercharger starts working against the engine and power drops off.

A smaller pulley forces more air into the engine, so it has the effect of increasing the gain....i.e. the slope will be steeper up front and you will hit max faster. Since the blowers are spinning faster, this also means you will hit the dropoff point faster also, but since the dropoff is typically in the high RPM range where you would upshift anyway, this doesn't matter as much practically speaking.

The height of the tabletop is set by the ECU, and reflects how comfortable the tuner is with operating the engine at that level. The more risk-aggressive the tuner, the higher the limit they may be willing to offer. It's a vendor hazard, since most tuners will not warranty the tune and YOU are the one stuck with the fried engine if something goes wrong.

HTH is saying....why bother with the pulley when you can raise the tabletop through a remap. It's a reasonable point, but it depends on what you want.
Most folks prefer acceleration to power (although they are related). Depending on which torque curve you look at, the stock F-Type reaches peak torque at around 4500 to 5500 RPM.
Both cruising RPM and take-off RPM are lower than this, so for real world feel of "punching the gas", the slope of the power curve actually matters quite a bit.
For example, the V6 and V6-S F-Type's have very similar power curves (see this chart) but different final drive ratios, which increases the slope of the power output relative to the press of the gas pedal. As a result, most drivers feel that the V6-S is more powerful and responsive than the V-6 even though they are usually driving within RPM bands where the engines are identical.

So a pulley swap to increase the gain can make a bigger difference to driving feel than a higher power limit.

In summary:
1. ECU remap only => can increase height of tabletop but has limited ability to increase power slope (limited by airflow)
2. ECU + pulley => can increase height of tabletop AND increase power slope

For most normal driving situations for the F-Type, increasing the slope creates more perceptible difference than increasing the limit, although with a pulley tune you get to do both.
Hope that helps.

 

Schraderade.

That is very helpful.

I have been very specific on what I am looking for. Your in summary #2,
" ECU + pulley => can increase height of tabletop AND increase power slope"
That is exactly what I want!

" so for real world feel of "punching the gas", the slope of the power curve actually matters quite a bit."

Bingo! Thus the reason for the pulley!

So real world everyday driving performance will be enhanced with a pulley and tune vs just a tune which is what I mentioned I am measuring.

30-70 MPH Real world driving
50-70 MPH Real world driving
60-130 MPH (Often used for acceleration comparisons but you probably do not get over 90MPH every day)

BTW-Eurocharged includes a 2 year engine warranty with their tune.

Schraderade, seems we are in complete agreement! Thanks again!

Walt

 

Good luck Walt- I am waivering over doing the pulley but have done the ECU. I have already had a 2nd version uploaded and there is no doubt the car is faster than stock. I would pay for the tune for the throttle response adjustments alone. I just pulled on cars yesterday up to 140 plus- and I applaud for your research; I look forward to the before and after numbers.

 

I'm a novice concerning tuning of cars... was wondering what the second version would do that the first did not. As well, I read somewhere that tuning often leans out the fuel air mixture which could lead to damage ... does ECU address this issue?
Glad you are pleased with the tune it sounds like the car really responded.
Lawrence.

 

Ive had a pulley and map done to my car only last week, the difference is certainly eye opening.
It didnt all go to plan to start with though lol.
I wont hijack the op's thread, i'll start another thread.

 

Please post here or start another thread. Lots of interest in this subject so we all want to hear your experience!

Thanks,

Walt

 

Ok, i found a co over here (Tom Lenthall) that works on and tunes all different jags.
I've been talking to them for some time about their tune and pulley, the pulley so im told is sent to America and is there design.
So anyway i got a base run done at a rolling road ive used before but they'd never done a f type before, we managed one run before the car went into limp home made and we werent sure how to reset it, found out after we'd taken it off the rollers!
We saw 525 at the wheels and the guy reckoned after another couple of runs it probably would of been 530-35 so not far off the qouted figures.

Anyway off i trotted to Tom's where i found out i was going to be the first f type they had worked on, gulp lol.
So they dropped me off in town and said it would be about 3 hours, true to there word 3 hours later they picked me and said all the work is done.
Off i trotted back to the rolling road, the roads back were quite congested so didnt really get a chance to give it some beans but it def felt stronger lower down.
So on the rolling road things werent good, we managed one run and it wasnt good, low down it was making more power but from about 4-6k it lost power and just dumped fuel into the engine, the fuel trim just went off the scale.
We reckon the ecu was just protecting the engine hence the fuel going off the scale, i phoned Tom who straight away was very apologetic and said he would sort it asap.
Me and Charlie (rolling road operator) reckon the map which was used for xkr's wasnt right for an f type, Tom phoned me back and said when it was convinient with me he would pick the car up on a trailor and take it to his mappers and live map it at no expense to me.
Well that was done last week and wow, roughly 50lbft and 55bhp more from 2k upwards, acceleration is obscene, midrange is mental, it actually catches you out it accelerates so quickly!!
I would imagine i'll get used to it, maybe lol
I need to take it back to the original RR to see what its making at the wheels now, doing that next week.

Cheers
Tim

 

My first tune was a very conservative box tune. Since then my tuner (OE tuning) has done multiple dyno tunes with other cars to further enhance the gains. One thing I like about OE is he doesn't push hard and hasn't with my cars over the last 11 years. So I always tell him I want tunes with proper timing and safe air fuel over maxed out gains. He says he can push it further but I told him Im good with this and he respects that.


Im still on the fence about the pulley. I know modding is a "pay to play" type of scenario and I mod all of my past and current cars but for some reason Im not ready for the pulley yet.

 

Timbo,

Glad it all worked out for you. Being the guinea pig for the inaugural F Type tune I would expect some issues. Hopefully that's it.
Sounds like a blast to drive and very much transformed.

Thanks for sharing.

Walt

 

HTH is internet speak for Hope That Helps, it's not the dudes name...

The tune is how the boost is increased. The pulley simple gets you boost lower in the rev range.

The "tune" is raising the setpoint for the boost limit which is what get's you the overall increase in power & torque. As I mentioned before the 510HP tune is running ~7psi, the 550HP tune is ~9psi, and some cars with aftermarket tunes have gone up to ~11psi. You get power by increasing the boost, then tweaking the fuel/timing to suit that higher boost.

The smaller pulley will make "more boost" and it will also bring on the boost lower in the rev range, but if the ECU is limiting the boost by opening the bypass valve then it only really has the effect of bringing the boost on sooner i.e. lower in the rev range. The overall boost is still limited electronically.

You will not be the first person to complain about lack of data, or references when it comes to tunes. So, have a look at the XKR's & XFR's on this forum, plenty of them have been tuned and a few members have gone into detail about the results.

How long is a piece of string?

Boost will start to be bled off as soon as the manifold pressure reaches the set value programmed into the ECU.

The bypass valve is open at idle, or when the engine is without load. It is closed when the engine us under load, and starts to open when the manifold pressure reaches the set value programmed into the ECU.

Here is the performance map from Eaton for the R1900 http://www.eaton.com/ecm/groups/publ.../ct_127899.gif
Trying to convert that into psi @ rpm is very complicated & depends on a lot of external factors. No-one will be able to give you results from testing on a vehicle either, because of the ECU bleeding off the boost.

If you look at a dyno graph as soon as the torque curve flat-lines, you are at "maximum boost" because the ECU is bleeding it off. Depending on the tune that could be anywhere between 7-11psi or thereabouts.

It's the tune that makes the most difference, the pulley is the icing on the cake. Look for the $100 Eurocharged are asking for the pulley as part of this special deal, you'd be crazy to say no. So just do it.

And this is where I sign off. I don't know why I bother some times...