Help! XLR Tune

[JJP]

I’m looking for a stock HPTuners tune for a 2007 XLR. Anybody?

 

[justdennis]

I had my 2007 V dyno tuned last year, the tech told me he was using HP tuner software. I don't believe HP had a "tune" for my car, the tech said he made his own tune. Take that for what it's worth, I don't know the guy personally, but I have no reason to doubt him. He is the owner of a local speed shop and he tunes his own race car. I know it's not what you are looking for, but I thought I would share my experience.

 

[JJP]

Thanks for the reply. The "V" Model calibrations will be much different dealing with the boost and extra fuel. If it wouldn't too much trouble, could you call him and see if he has a stock base model tune?

 

[justdennis]

Yes, I can do that, I'll try to contact him tomorrow.

 

[JJP]

Many thanks

 

[justdennis]

The name of the shop is SpeedLine Performance, in Ocala Florida and the owner is Michael Carpenter, he does the tuning. He said he does not have a tune for your specific car but could tune it similar to the way he did mine, that was making changes after each dyno run, there were 3 runs. I'm not sure that will help you being you live so far away. If you still want to talk to him his number is 352-877-3655. Before you call let me give you some more information as to why I did the tune. I had recently purchased the car and had no experience with modern supercharged engines so I was looking to have it checked out to make sure everything was working as it should. I was also curious about what the horsepower really was, and how to get more. Michael said he could tune it but to make much of a difference he suggested we make a few changes. We went to a slightly smaller pulley on the supercharger, maybe 3 more psi and modified the catalytic converters to allow them to flow better. It definitely made a difference. I never race the car, but I really enjoy scaring the heck out of my wife. That being said I'm not sure you'll gain much without making some other changes, if Horsepower is what you are after.
Good luck,
Dennis

 

[mickeytee]

Curious. What would you be calling a stock tune. It would be one or the other. The car is stock or you want to be able to tune it. People a lot smarter than I am have told me there is only one way to tune a base or V. That would be with a piggy back ecm.with a tune you can change injector size,ignition time fuel ratio, valve timing. The xlr end is locked. Meaning you cannot change anything in it. You have to install a pre eco that takes the readings from the factory and over rides them . very costly.. Since there are no aftermarket performance parts for the base what would be the purpose. To add a turbo or supercharger and make all the parts to go with it to make any hp you are in the 10's of thousands. Sell the base and buy a v. You just got the hp and saved money. Because of the variable boost on the v a mild pulley upgrade is compensated by the factory end and increases fuel according to boost. There is no way to tune it for hp using an ls or other tune as our firing order is unique. I have a friend at Holley who is working on a tune for the North star guys that use the engines in dunebuggies. It will be a stand alone ecm and many features on a street car will not work once installed

 

[mickeytee]

Dennis, did he claim to make any changes other than the pulley and cats? Did you go with smaller upper snout pulley? D3 the caddy guys said they got 2-3 pounds boost with it but went with the smaller p/s pulley to get the 5-6 they claim. What most call a tune involves setting timing, air fuel mixtures etc . none of these I have been told can be done on the 4.4 or 4.6

 

[justdennis]

It was the upper snout pulley changed to a 2.55in. Smooth Flow. I was there when he did the dyno pulls and I took pictures of the computer screen after each run, here are the numbers,

Run #1 Max Power 373.21 at engine RPM = 5.74 Max Torque 382.80 at engine RPM =3.94
Run #2 Max Power 381.38 at engine RPM = 5.93 Max Torque 389.10 at engine RPM =3.92
Run #3 Max Power 386.04 at engine RPM = 5.85 Max Torque 398.85 at engine RPM =3.98

I remember him saying at some point he added a little more timing on the last run but I'm not sure what other changes he made. He also commented that the inlet air temperature was at 150 degrees and that may affect the horsepower numbers because the computer will start to pull timing. What really got changed I couldn't say but he did make changes on his computer after each run, but he didn't tell me what he did. I just assumed he didn't want to share his knowledge.
One final point, recently I changed all 4 of my VVT actuators and that sure increased low end power, I'm not sure if that would have made a difference on overall horsepower, any thoughts?

 

[JJP]

Those are respectful numbers, but I would have expected a bit more with the pulley change. The IAT seems a bit high. I would check your intercooler for obstructions.

 

[mickeytee]

Almost every vi I Have ever checked the supercharger was out of fluid and the pump did not wotk. You can only change the leg so small before major port ing on the manifold and then the belt starts slipping due to it being so small. A 2-3 pound boost increase is all you can expect.

 

[justdennis]

I was disappointed that he didn't do a test run before we made the changes so we would have a baseline to compare it to. He did have concerns about the pump, so we switched it with one he had, but that was before we did the dyno runs. He said he refilled the coolant but the next day I checked it and it was a little low but not much. He said the numbers would be higher if the IAT was lower, he claimed 1 Hp for every degree, but what is normal or ideal? In all fairness to him it was July in Florida so it was hot and humid. I'm curious if the numbers would be different now that I changed the VVT acuators. Whatever it is, it's a blast to drive and isn't that all that matters.

 

[mickeytee]

Almost every vi I Have ever checked the supercharger was out of fluid and the pump did not wotk. The for magnets if bad will keep from advancing the cans. Default if they don't work is economy mode. If they don't get full voltage they won't pull out the acuators thus not advancing the cams for performance.

 

[justdennis]

That makes sense and would explain the change in performance I noticed.

 

[GizmoQ]

I never thought I'd be racing mine when I decided to buy an XLR, but it only took one test drive in the base and one in the V to convince me I wouldn't be happy with the base.
I agree with Mickeytee, its more cost/benefit to buy a V.

But, a piggy-back ECM isn't necessary. I've got three HPTuner files for my car: 480rwhp limp tune, 499rwhp street tune(93 octane 50% alcohol), and 526/548hp/tq full race tune (28psi boost, 100% alcohol, 109 octane)

JustDennis: On the issue of IATs, you lose 10 degrees of timing as soon as IAT2 exceeds 128 degrees. It not gradual, its quite abrupt. Next, I think, is 5 more at 156 degrees... again all at once. I believe theres 5 more taken around 165.

 

[JJP]

Wold you mind sharing those HPTuners files?

 

[GizmoQ]

I wouldn't mind, but they're worthless to you without all the mods I've done: Snake Bite, injectors, porting, headers, Super Chiller, alcohol injectors, etc.

I'd also have to clear it with my tuner.

 

[mickeytee]

How did you get 28 pounds of boost? That's more than d3 acclaimed with their smaller p/s pulley and the smaller on on the supercharger. They reported at 5500-6000 the SC pulley slipped and would loose boost. I was thinking the most they got was 20 pounds with their 8000$ modification. I may be wrong. I was not interested at the time but now may buy a v to keep

 

[mickeytee]

Well that sounds promising. A lot more that others are getting out of the engine without a shot of nos.

 

[JJP]

I wouldn't mind, but they're worthless to you without all the mods I've done: Snake Bite, injectors, porting, headers, Super Chiller, alcohol injectors, etc.

I'd also have to clear it with my tuner.

I'm no stranger to HPTuners and have been tuning LS2 and 3's for 15 years. If you have a stock tune and modified tunes, I would like to see what those mods have done and to what degree. I'm in negotiations for a 2006 V now. Tell your tuner that I respect his work and would be happy to sign a NDA protecting it.