I'll put my two cents. Lots of factory cars are detuned on purpose from their full and safe potential ,it's done either due to an upcoming newer competing model with supposed higher hp or for emissions purposes. That's where proper ecu tuning comes in. I have been at nearly 100 horsepower gain , (434 to the wheel on Mustang dyno or around 470 on Dynojet) for more than a few years now on my 08 XKR. Lots and lots of track and testing time and am currently sitting at just under 100k miles. Have tuned numerous XKR, XFR, XK, XF cars pushing lots more power and done safely.
My 08 Xkr keeps up with and it's nearly identical in track time with 550hp CTS-V for example, you guys can find a lot more comparison drag runs on my youtube . Here is the latest one against newest Stingray Corvette

 

https://www.jaguarforums.com/forum/x...epower-168474/

 

🤣🤦🏽‍♂️

That thread is pure entertainment.

“You mean hp at the crank right? Not a chance to get near 500 with the Eaton blower, unless you stick a 100 shot of Nitrous on it. Even 450 is extremely optimistic.

The limit seems to be 350-360rwhp (on American dynos ) which has just taken a few S-Type R's into the 12's. That's not 450hp at the crank...”

The limit is 350-360whp on American dynos? 🤣

Please tell me how I put down 348whp and 368wtq with just my 3.5” banshee screamer and an H pipe then... 🤨

I’ll put down 400+ without a tune easy with the rest of the bolt ons and a pulley.

 

I agree, the heaton has to go. It’s definitely good for much better than 13’s though.

You do realize the M112 is the same
blower used on the 03-04 terminator cobras, right? You can definitely make enough power with it to go well into the 12’s or even 11’s.

Horsepower isn’t the only factor in the equation though. You can have all the power in the world and still be slow.

 

More money than brains? If you want to be insulting we can be insulting...

I’m not super wealthy by any means, but I do know how to make money and my bills are paid and my cupboards are stocked so if I want to spend my fun money on customizing and modding my car, that’s my business and your concern for my finances is misplaced so worry about your own...

As for the brains... I scored an IQ of 128, and finished high school at 14.

Since we’re passing judgement... Based on your comments I’d assume you’re an old, broke, bored geriatric who feels the need to troll and impose his unneeded .02 and unwanted opinion on automotive forums to feel relevant.

Type less and drive your cat more. Quit worrying about other people’s money. Weirdo.

 

you can have a hamster breathing into the intake tube and a 4.6 4v will pick up 50whp. the aj doesn’t breathe or respond like a modular. jaguar already was pushing 13psi on the heaton stock, the 3lb pulley needs better cooling and meth to not trip over itself.

you’re also right there. these cars have horrible stability control and open diff = constant traction problems. there’s very well documented solutions to that of course

 

I can change all the parameters and more ... MAF, Injector rescaling ....

 

YOU might have soft carbon build up. I put mine through it’s paces regularly, and my 348whp dyno shows it’s plenty healthy. 120k on the clock and runs like a champ. 💪🏽

I put 4 lengths on an E43 AMG just the other day.

Iono what else to tell you bubba... Performance cars like to perform... 🤷🏽‍♂️

 

Still learning these cars but they seem to want to breathe but are very restricted. Opening them up has excellent results.

I noticed it when we dyno tested the screamer intake I designed. Just replacing the upper plenum with my 3.5” tubular design we picked up roughly 20whp and 18wtq in the mid range and 12whp and 10wtq at peak rpm.

The result was 348whp and 368wtq with just the intake plenum and an H pipe and mufflers.

Considering the RR plenum gives around 12-14hp at mid range and nothing at peak rpm, it tells me the oem design is nerfed and it’s choking in factory form, which is why the dyno shows a huge benefit from the larger diameter plenum.

My dyno shows power carrying to redline... that tells me the thing wants to breathe. Especially when small changes net big gains.

I’m getting rid of the cats for test pipes, and the smaller pulley, etc then doing more dynoing.

This engine is solid... it wants to make power. I gotta give it what it wants lol.

 

I'd suggest reconsidering that plan.

 

@Joel Brown,
I am by no means an expert on the issue.
Since I am reading this forum, I have learned a lot, and I was very interested by the experiences of fellows much more skilled than myself in attempting to increase the perfs on the 4.2 SC X350 (even if not my own goal).
My understanding is that the engine is already not far from optimisation and that there are a number of limitations, e.g. the Eaton or the diff, that would inhibit much increasing the perfs unless spending substantial money.
Putting a LSD, a twin screw and other upgrades seem to allow gains but at a cost.
I am sure that our community would welcome your attempts and follow with enthusiasm your project.
Please do it and report!

 

So it’s ok for others to insult me but I can’t retaliate and you're not going to address them or come out of your moderator hole to correct them for doing the same first?

A+ moderation there... totally unbiased and not one sided like a mod should be.

Bravo. 👏🏽👏🏽👏🏽

 

The comment applies to everyone IMHO you carried it further than the others and obviously can't take a gentle hint.

 

 

Applies to everyone but I was specifically quoted and addressed?

BS. Don’t try to backpedal because you got put on the spot. You wanted to be a moderator so be a moderator and moderate accordingly.

 

Sounds like a plan.

 

Well bubba yourself old boy. If you did not have the car from new I guarantee you have soft carbon build up.

But of course you could prove me wrong by showing the top of the matrixes in the charge coolers as well as the u bend under the TB.

I will not hold my breath.

If you hold up to your boasting good for you however you seem to have an extremely "thin skin" and a lot of "hot air" so far.

 

way to go alex. Sweeeeeeeet

 

bravo Norri. If i ever get to your part of the planet , suds on me

 

can you change those parameters using SDD?