I've been sitting on the sidelines on this thread, but based on the results it seems like this is not a bang for buck modification, albeit we need more dyno runs and can't limit our analysis to just one example.

Time to stir the pot:

Why did this forum member get a much larger gain on his XJR in Romania?

https://www.jaguarforums.com/forum/x...ap-dyno-98920/

27rwhp gained.

 

^ I didn't want to bring it up, but now that you have...yeah, i was wondering about that too...

 

I see he has a 2005 X350 kind of XJR. Does it have the same PCM? (Denso 32-bit twin-cpu etc)

 

If it's 2005MY then it's the same as mine, so yes it's the earlier Denso 32-bit.

 

hmm... a bit dubious of that claim in the XJR, but wonder what software the tuner used to mod that particular car...

 

My thoughts exactly for a non-turbo car. Were there dyno charts on his thread of power gained?

 

Looks like it, yes. Click on link...

 

Yeah, being a newer member on here I didn't want to be the guy to kick your bucket over and say you got cheated but.... that small of a gain on a forced induction car with upped boost, exhaust and intake is pretty bad. Did you get to see the before and after fuel and timing maps and what changes he did or did he pull the "you can't see my magic" trick? With my experience setting up FI cars and tuning I'd be pretty miffed if that's all I got from an 800 dollar tuning session on a modded over stock forced induction car.

As far as software I doubt he's using anything proprietary or mysterious. The trick is he has the definition files, If we had those files tuning jags could be as easy as tuning Lancer Evolutions or Corvettes.

 

And not to thread jack but, Imho If you want an idea of the possible direction and potential of the S-type R look at the Mustang Cobras. Similar engine architecture and layout same super charger, some obvious differences (the STR's induction design doesn't look the greatest for flow) but similar overall.
I will soon be starting on taking my 04 to it's full potential using the m112 so we will see where that winds up.

 

I think 10-15HP is a realistic gain with these cars.

As I said in a previous post here in this thread (#91), I had my XJR on the dyno last Wednesday to specifically look at the air/fuel ratios to see if there was much to be done in the way of a tune. The answer was "not much, maybe 10HP" which is pretty much what we have seen with the Eurocharged tune.

It's easy to get excited when you look at those sites in the UK where tuners claim a 10% increase in power; 400 up to 440, but that's really just an optimistic guess, funny how all the different cars listed all gain 10%...

I'd still be interested to see a printout of the AFR with the HP curve, at the very least to compare to other dyno charts so we can see what's going on there.

 

I'd like to see the old and new fuel and timing maps because I for one do think this is a small gain for a modded supercharged V8.
Time to get some et's and trap speeds at the drag strip, that will give a true reflection of the power your making.

The fact that he threw in a box tune without even doing any datalogging is a big red flag. I bet there's a good amount of improvement left untapped that a proper tune would bring out.

 

As interesting as all this is. Put two fat lads in the back of your car and those gains are gone. $800 for nothing!

For such a forced induction unit these gains are poor IMO. I would expect a N/A engine to get between 5 - 10 BHP in gains after mods and a re-map. I suspect the STR has a high level of tune from the factory not leaving much meat for the after market tuners.
It's not a good bang for buck mod IMHO.

 

not sure if i follow this particular logic...

but,

the value proposition of this tune is really up to the individual STR owner,

there is a lot more to judging a a tune than just its peak numbers,

i've done plenty of mods on my STR, none were cheap. most of them made small gains, i'm still pretty happy,

Any meaningful gains will need a twin screw KB upgrade for that 100-200hp extra, but you think that is any cheaper dollar-for-dollar or easier to do?

$/hp rating : par

 

This research project was set up, well-controlled and funded entirely by GT42R, and at long last answered a question for STR owners. The findings were of real value to me and all the others who offered encouragement to GT42R, but otherwise just sat back and waited for those well-documented results.

No, I will not spend $800 to gain 15 HP, but at least I now know the facts. After the 40-or-so HP to be gained from filters, intake elbows, high-flow cats and exhaust mods, the twin s/c is the next upgrade option.

 

Seems like a whole lot of money for a whole lot of nothing! You can put a $30 intake on a civic and get 7hp.... Kinda disappointing to me. Just my opinion. It's frustrating to me cause our cars a a V8 supercharged! We should be able to gain an easy 50 horse out of these by intake and exhaust alone not go mention a tune.....

 

what pray tell are you basing this 50 hp on? ive never seen a tune or chip gain any more than 5-15 hp on a gasser... now my diesel truck,, different story... sounds like if you wanna maximize hp you will need to do every mod available...starting with air in and a pulley.....but that E 55 amg is still going to leave you behind....

 

At least it will be close:

 

I'm talking about every turbo car, diesel truck, and MOST supercharged vehicles. There are tunes for everything that make big increase in hp numbers. Again it's frustrating there are no companies or tuners who can get inside our ecu's to do this. I bet there is so much power to free up that nobody has yet to unveil....... But yes in the mean time I will be purchasing a pulley, intake tube, and a friend of mine at RLD Fabrication will be making me a custom exhaust!

 

There are tunes for these, see previous threads.

 

TURBOS AND TURBO DIESELS YES, but after the pulley change the STR is about maxed out.......take out the seats..... ; )