In response to both specific and general requests for input on this flash and pulley combination, I'm submitting an initial report.

Caveats:

1. I did not dyno the car before the work, and have not yet taken it to a dyno since the work. As I explained in a post on another subforum, I am a true believer in the dyno as a diagnostic and tuning tool--every one of my cars for the past two decades at least, including the other ones in my sig, have been to the dyno, several times. My 930, in particular, has a Motec M48 ECU in place of that car's original CIS system, and to get that unit dialed in correctly the car had to practically live on a dyno for several hours over several days.

So I get it. But, unlike the Porsche, the Bimmer, and my other boosted cars (like a cool NA MR2 with an aftermarket turbo system on it years ago), this XKR is NOT my car, in the sense that it is my wife's car, given to her as a birthday present. It would have provoked all kinds of eye-rolling, at best, if I had "given" her the car, then promptly thrashed it on a dyno, modified it, then thrashed it again on a dyno, then tracked it. That simply was not going to fly.

So, I modified it with springs, spacers and the ETG tune and pulley. She likes the lowered look, which is good, and at some point I predict I'll dyno it, and when I do, I will report back. Dying to know how it does, actually, being a numbers kind of guy.

2. I have not tracked the car yet. See (1) for the reasons. That is actually probably further down the road than the dyno, unfortunately. She's watched me drive the 930 on a track

3. I also lowered the car, as mentioned above, and that changed its driving dynamics somewhat, so the overall feel of the car is a function of both the engine mods and that mod. The car dropped 1.3 inches, and the spacers are 20mm all around.

4. These impressions are based on about 800 miles of "street"--that is, not track--driving. Under no circumstances could I safely even get close to the limits of this car's abilities for any extended period of time on public roads. You can only do so much on highway entrance ramps and maybe 50-60 miles of sparsely driven back country lanes.

So.....

To me, the first rule of all mods, engine or otherwise, is properly borrowed from medicine: "Primum non nocere", or "first, do no harm". On that score, this engine mod seems just fine. There is nothing about the car's driving characteristics that seems worse than before the mod. There is no bogging or flat-spotting at any point in the rpm band I've been able to explore at any length. I can detect none of the usual signs of detonation (signs I have heard in other cars, believe me).

A. Throttle tip-in is sharper, and the throttle seems distinctly more linear than stock, but it is hard to quantify these impressions.

B. On the butt dyno, the car definitely pulls more strongly, with most of the gains appearing to come at rpms from 3500 and up.

C. Mileage on low boost driving has improved maybe 1.5-2 mpg, based on a couple of tanks both before and after modifications. On boost, forget it .

D. With the car lowered and aligned, turn-in has gone from excellent to superb. Lightening quick, but not darty. Body roll, which was good before, is now truly minimal for a car of this weight. It may sound like heresy, but I am actually enjoying this aspect of the mods more than any other. Would LOVE to take this out on the track now. Of course, on the track, I could more properly explore the engine mods, so they might take over the number one spot

Driving dynamics do change with the springs, though. Road feel is more immediate. This will be a highly personal decision. The car is still far less rough than my 930, but that suspension is truly purpose built. The Jag is closer now to my Bimmer, which has a Dinan suspension, meant for track and street, except minus camber plates. Overall, I'd say maybe the XKR rides maybe 15% "rougher" with the springs. Another way to describe it is that it is still ok with my wife, and she was driving a 2004 XJR on stock 20's before this. She notices the difference, but it doesn't bug her. Personally, I prefer it over stock, but that's just me.

The tune and flash logistically were not a big challenge. It takes Jaggs a while to get his puller and laptop package lined up to send. At his recommendation, I had him drop-ship everything to my wrench, whom I've known for many years, since we are both gearheads, except he makes his living on it and owns his own shop in the shadow of Google and Microsoft here in the Seattle area. He sees a LOT of high-end cars. He reports that although the puller fits fine, it takes a real hard tug to break the stock pulley loose, one that is intimidating to somebody that hasn't done it before.

The tuning Jaggs does himself, remotely, assuming good internet connections. He says that he gets the latest programs from Jaguar itself for the car, then installs them along with the basic XKR-S engine upgrade.

As Jaggs explains it, though, I am not sure exactly what electronic improvements (other than removal of the top speed limiter) are accomplished if you flash an XKR-S, as opposed to an XKR. The selling point for the XKR flash is that you get an XKR-S tune on a mechanically identical XKR engine. Add 1.5 pounds of boost with a smaller pulley, lower the car 1.3 inches (which leaves it .9 inches lower than an XKR-S), and the performance difference is now down to the XKR-S exhaust, which he says can be attained, as far as numbers go, by installing a Quicksilver cat-back exhaust.

But if the flash of the XKR-S doesn't yield more hp or torque, then I'm not sure why it's worth paying 2 grand for it, unless the flash for that car goes beyond a factory Jaguar tune, and that's a riskier proposition, at least on paper. A smaller pulley would add 1.5 lbs of boost, like with the XKR, but that kind of increase is within the ability of the XKR-S stock ECU to accommodate, as Jaggs says. So what does the XKR-S flash do, exactly?


Anyway, I didn't push too hard on this issue, because I don't own an XKR-S, but others who do might want to do so.

Jaggs seems like a committed and enthusiastic salesman, with a lot of confidence in this particular tune. That said, he is a busy dude, and I am not surprised to hear that he has not gotten back to Matt about wrenches in Matt's area to do the work. I had to pretty much arrange everything on my end, and then Jaggs came through fine.

So that's it for now. So far, I'm glad I did these mods, and look forward to the day I can quantify the gains and improvements, at least over factory stock numbers, my oh-so-sensitive butt perceives

One more observation I will leave you with, though, from my wrench and buddy who installed the mods, and then drove the car well beyond the 105.3 miles required for break-in, including, he later confessed, a rolling start drag race with his shop's drag car (a tricked-out 442), from 10-80 mph, which the Jag won by 3 car lengths:

"I have driven and wrenched all kinds of high-end cars--Benz, Audi, Porsche, BMW, Ferrari, Lamborghini, Aston Martin and Bentley. My new favorite car is yours. It combines truly superb performance with British elegance inside and out. It has a very reasonable price tag, relatively speaking, and is quite rare on the roads. This has now replaced an Aston Martin as my 'realistic dream car'".

High praise, indeed, given the cars this guy works on, and I see regularly in his shop

 

Nice! Congrats. That thing must be a beast. I did find more low end torque than the motor tends to run out of steam at higher speeds but again I only have the 4.2L. Also, possibly I upgraded to a bigger lower pulley along with the smaller upper pulley. In my butt dyno, I thought the pulleys (upper and lower) made the most difference. I also did Viezu Tuning, hiflo cats, exhaust and air induction afterwards but didn't seem to have that much of power gains on my butt dyno than the 2 pulleys. Also, with all the mods, my stock AMG still feels much quicker especially passing power but again mine is only the 4.2L and not the 5.0L.

My main problem now is heat soak on the supercharger. You might want to consider getting the killer chiller or water/meth kit. I can tell the car is robbed of power during hot days after running around for awhile. I was planning to do one of these kits this year but I drive the jag so little (1,900 miles a year and probable half that this year so far) that I just can't justify doing the kit for now. There is a nice writeup on the killer chiller in the S-Type section.

 

Good thoughts. But the sweet thing about the tune and pulley is that it is basically undetectable to the dealer unless he is looking for it, and I am in the warranty period for quite some time. Even given the protections of the Magnuson-Moss Act, which requires that a dealer/insurer prove that a given modification directly caused any given malfunction or complaint before coverage can be denied under a warranty, it seems best to me to lay low for awhile on truly visible mods.

On the springs, I'm out of luck, as I am sure they are detectable with a halfway decent look. But I'm pretty confident now that they won't cause damage that would otherwise be covered under warranty...

 

Thanks for the report. I also talked to Jag's when I was considering the tune for my XKR 175, which I sold for my 2013 XKR. Jag indicated the performance gain would put the HP at the 600 level, which is much more than the XKR-S. So, in this respect I'm a bit confused with the XKR-S flash parameters being used. With the pulley change your flash would need to be different than the XKR-S. I can see someone doing this to reach the 600+ HP and equivalent torque gain. But to just flash with a XKR-S mapping is not worth $2,000. Is he getting the map from Jaguar for the XKR-S free and than charging $2,000 for the same map (over/over again) with maybe a few tweaks? We need proof of added value and specifics of what is done. Surely this is not asking for too much for $2,000.

 

Bruce, thank you very much for the detailed report on the ETG tune. I really appreciate you taking the time to share your experience with us.

Recently, I was thinking along the same lines as DGL. I noticed on the ECU Tuning Facebook page that they are tuning XKR's to ~600 HP with tune/pulley. So they can't be using just the XKR-S tune if that is the case (unless of course it is a modified version). Maybe it's an option for the XKR people to install either tune and most are opting for the higher power, but modified tune?

https://www.facebook.com/pages/ECU-T...32907553487475

Having ~600+ reliable HP on tap sounds great. Just wish it was like my Softronics tune on the 911. The tune came with a cable that plugged into my laptop and to the OBDII, so I could flash the tunes myself in the garage or revert back to stock at anytime. That was a great tune, too.

 

My recollection from my talks with Jaggs is that the ECU with the XKR-S tune is "smart" enough to adjust appropriately for a 1.5 lb boost increase, so there is no extra modification required over and above the XKR-S tune. I believe that is why he doesn't recommend or offer a 3 lb. pulley--that would require enrichment beyond the parameters of the ECU.

What I don't yet understand is what sort of tune he is offering for the XKR-S.

 

The stock XKR-S is ~550hp, so is it possible that only 1.5lb of boost w/ ECU enrichment is going to make up an extra 50hp? It just seems like the 600hp XKR's must have a slightly different tune than just the stock XKR-S one. I could be wrong, but it seems strange to have that much HP bump for only 1.5lb extra boost.

Of course, a phone call to Jags could clear this all up.

As for the XKR-S tune, I believe he said it is just modified a bit further and the XKR-S has a more freely flowing exhaust so it makes a bit more power.

I might email or call him today and ask a few more questions.

 

If you do, Matt, please let us know what he says. I am curious...

You may be right, though, now that I think on it. I could see maybe 30-35 hp on a 1.5 lb increase in boost. 50 is pushing it.

For me, e-mails were a spotty way to connect with Jaggs. But if I got him on the phone, he'd be generous with his time. Not always as specific with his answers as I would like, but generous with his time

 

Whether they now start with an XKR-S map or still use the XKR map probably doesn't matter as it's reprogrammed anyways to make more power. The XKR-S makes some of its extra stock 550 hp from its lower restriction exhaust, and the rest from more aggressive tuning, whereas the XKR gets it all from more aggressive tuning. Both need the extra boost to approach 600 hp.

The $2000 includes the software upgrade, use and shipping of their laptop up to 3 times, new pulley, shipping and use of their pulley puller, lots of consultation, and hopefully enough markup to cover a multitude of business expenses and enough profit to make it worthwhile. Price is reasonable, even if something similar is available for less on more popular cars.

 

Bruce H., just wondering, do you have the tune or have you talked with Jags about getting it?

The initial conversation here was the XKR is using directly the XKR-S tune with the pulley. No modification to the tune. That is why some XKR owners feel safer since the XKR-S Jaguar tune is tried and true. But in looking at the gains, it appears it must be modified (as you have stated and I agree) to reach the ~600 hp range.

Just emailed Jags, says use of the pulley puller is an extra $195, which is fine. I don't mind for people to make a profit, its a business after all.

Looks like I might be getting this done.

 

Matt, if you do this, can you dyno before and after, or do you have "restrictions" of one sort or another as well ?

My price was about $2200, as I recall, with $1999 for the tune and $195 for the puller/laptop

By the way, I was right about the dealer noticing the springs. Had to drop by today to get a rear brake light assembly ordered (was missing one LED light, and the only repair is replacement of the entire assembly). First thing my service rep said to me was "you lowered it, didn't you?" Then two more service guys came out and they all walked around the car, asking me the details. They said they noticed as soon as I drove in that it looked "lower, wider and meaner", and gave their stamp of approval.

So much for stealth And it's not exactly slammed. 1.3 inches and 20 mm spacers is pretty mild in some quarters....

 

I absolutely plan to do that.

Jags said he found a shop for me here in Houston to get the pulley installed for $200. I replied back, "Great! Where is the shop? Houston is a BIG city." And he hasn't replied back yet.

So, we are back to square one. Hopefully I will here from him soon. I am not sure if he actually has a shop lined up or not....this is the exact spot communication stalled last time. I am assuming he is just busy. But I would like the shop to have a good dyno, that would make it much easier for me. Also, I know some of these local performance shops from my other cars so I hope it isn't a place I want to avoid.

We shall see!

 

Matt, if you know your own place you like, I'd use it...

Jaggs offered to do the same for me, and not only was it clear he had no idea about who was good in my area, I had no idea when he would get around to it.

 

I spoke at length with him, and have chosen not to use his services. He was unable to answer some of my fairly basic questions about the tune, and his local affiliated dealer didn't have the first clue.

ETG was offering an XKR tune before the XKR-S was built, but may very well have switched over to the XKR-S tune at some point. Either way the basic tune makes more power by leaning out the air/fuel ratio slightly, which he acknowledges absolutely requires a minimum 91 octane, higher is better, and this octane level helps guard against pre-detonation.

If you do the pulley as well then air/fuel ratio changes, and possibly ignition mapping, will be adjusted to work at the higher boost levels, and maybe the stock XKR-S tune has enough safety margin to handle the higher boost. Higher boost requires less aggressive ignition mapping than lower boost to avoid pre-detonation...or higher octane to compensate. But any way you slice the tune is more aggressive, meaning it makes more power and reduces the safety margin against pre-detonation, and the only thing you can do to help compensate is to use higher octane gas. I do that religiously with two cars that are modified for track use, and have improved intercooling and added water/methanol injection to one as further safeguards against pre-detonation.

I examined dyno data-logging of this tune on BigCat09's engine and found that the transmission control unit overrides the ECU tune to limit boost and torque in the mid-range. This is Jaguar's attempt to protect the transmission, in the same way that their ECU tune protects the engine. It seems half hearted to increase engine power just to have the TCU limit it...but that's where we're at. And this is why member's seem to struggle to say whether they can really feel much difference after the tune install, and why 1/4 mile acceleration times never improved much after the tune. There's been efforts by another party to get into the TCU to remove its limiters, but that project seems to have stalled.

I decided not to do any tuning to the car after I more fully explored the car on the track. It's got the power and gearing to be really fast down the straights as it is, and any kind of performance improvements for street or track need would need to come from other areas like better tires and weight loss. Many of you already know the tires can't handle the power it has now. I recently tested acceleration from 50 mph with DSC OFF, and when I nailed the loud pedal I put down a pair of black marks close to 100 feet long as I dialed in counter steer. That was on a coolish day with the intercoolers not heat soaked from hard driving or high ambiant temps. The tires also lose grip when pulling out to pass and cross painted lines.

If he's hard to reach ETG to give Jaggs your $2000 I'm not sure what that means if you have a problem down the road and need help. The charge for puller must be something new over the last year or two.

Bruce

 

Bruce, I'm interested in your reading of BigCat's data logging, and especially your conclusion regarding the TCU. Jaggs told me that his tune now specifically modifies the TCU, presumably to compensate for the effect you describe. If the TCU is limiting torque in the midrange, it is doing so seamlessly in my car.

Now, I REALLY want to dyno this car, damnit!! Because I suspect that it will show measurable gains over stock. I'm also quite interested in the AFR's up and down the rpm and boost range...

 

I am really going back and forth about this. I remember reading something about the tcu but I thought it had something to do with the two wheel dyno and the car not liking it. I guess I need to look more into this before plopping down two grand.

Jags did get back with me on a shop. He found one that is reputable and even participates on some of the local car forums. They even have free BBQ on Saturdays.

Thanks guys for all the input in this thread.

 

Maximum boost was recorded at 10.10 psi with the tune, and that's basically stock boost, IIRC. I haven't seen anything about them doing a TCU remap, so it would be interesting to learn more about that. A dyno from any Jag with the 5L S/C and the new remap will show improvement in the shape of the torque curve compared to other dynos already posted previously. Is there a new dyno anywhere that you know of?

Bruce

 

There should be! If you go to ETG's Facebook page, for example, there's a post on there regarding a 620 hp XKR-S tune by one of his "dealers". That implies to me, at least, that there's a corresponding dyno sheet of a run on a wheel dyno, with an adjustment back up to 620 flywheel hp to account for drivetrain loss. If not, or if there isn't some dyno sheet somewhere showing the same numbers, then that number would be truly made up. It's gotta come from someplace.

https://www.facebook.com/photo.php?f...type=1&theater

Jaggs told me that his tune affects three basic parameters--fuel, spark and tranny. What it does to each of these I do not exactly know.

 

Since nobody is measuring bhp they can use any adjustment factor they wish and say whatever, but where they estimate ~600 bhp for the XKR the exact same tune will certainly make a little more on the XKR-S due to the lower restriction cats improving engine volumetric efficiency at the higher flow rpm where peak hp is made. Same tune, same boost level...just more air flowing through the engine at high rpm and making more power from it.

So it looks like there has been no improvement to peak hp, but with a TCU program I would expect to see peak torque increase substantially, which is in the mid-range as opposed to high rpm. If you ever find a new dyno and peak torque didn't increase then you know the TCU program didn't change either.

BigCat09 posted ~475 whp and ~420 torque dynos, with Mina rear exhaust and no air filters, on that dyno on that day with SAE dyno correction vs unadjusted. A stock dyno shows ~420 whp and ~405 torque. That's just an increase of 15 torque (barely noticable added push back into the seat) and an extra 55 whp which would definitely help in overall acceleration. That shows the restriction of the midrange TCU peak torque limitters vs no limitters at high rpm where peak hp is made. It'll be interesting to see if the newer tunes make closer to 450+ torque.

Bruce

 

This is a great discussion on the ETG tune. I'm sure a lot of owners are interested in getting this done if only there were tangible evidence of performance gain such has track times, dyno sheets and obvious feel. Also, a detailed explanation of what is changed and why. Is the TCU restricting the tune and why? What are the risks? Is the transmission robust enough to handle the increased torque?

What's stopping the XKR from putting the available power to the ground better. Other high performance cars with similar and lower horse power and torque specs out perform the XKR even from a rolling start. Is the XKR's DSC and transmission restricting the performance. Maybe the TCU is limiting the release of the power effectively. Although the ZF transmission is a traditional slush box and not a modern dual clutch it does seem to shift quick.

I wanted to do the ETG tune to my sold XKR 175. I almost met with Jag's last time I was in LA. He offered to go for a coffee with me but I could not find the time. I'm still not convinced the ETG tune offers an over all tangible performance gain. A $2,000 premium, risk factors and warranty issues are a lot to give up for little over all gain.