Kurt's 2008 GT500 VMP TVS 719rwhp/706rwtq

[READY GO]

Here's some initial results of Kurt's '08 GT500 with:

VMP TVS w/ 2.5" upper pulley, VMP Hi-Flow Elbow, L&M 72mm TB, FRPP 113mm CAI w/ VMP HPX MAF and JLT RamAir kit/Shelby KR lower grill, IW 10% OD lower crank pulley, STOCK 47lb/hr injectors and fuel rails, KB Dual BAP (full-time), Dynatech 1 7/8 LT headers, 3" catless X-pipe, 3" Magnaflow exhaust, Afco Dual-fan HE w/ larger reservoir, Motorcraft plugs (1 step colder/0.035" gap), PST CF shaft, MGW billet (adj.) shifter, stock 3.31 gear/axle, Spohn/Shelby/UMI/J&M/etc complete suspension.

Dyno testing/tuning done by Marv at C&M Automotive Performance. (Mustang specialist/Dynojet tuner in SE Wisconsin)

Initial baseline dyno yielded 685rwhp/680rwtq w/ 16* timing/19psi/93 octane/ CATS!! (subsequent removal of cats revealed the Right cat to be 50+% collasped after only 500 miles). Baseline tune showed a dangerous WOT 13.5-7 A/F across the board. The fuel curve was boosted 12% across the board which yielded a desired WOT 11.8 A/F.

After replacing the cats with off-road 3" pipes, programs were worked-up for the HPX MAF, the L&M 72mm TB, and starting specs.

The first dyno pull yielded 719rwhp/706rwtq w/ 17* timing/20psi/93 octane w/ Torco accellerator. The stock 47 lb/hr injectors were 100% duty-cycle/11.8 A/F until 4500rpm and appeared to go WOT rich (10.3 A/F) at 4500rpm and then WOT lean (13.7++) at 6000rpm. Max fuel psi was set to 52psi and was very irratic, so timing was cut to 16* for next run and some fuel changes were made.

The second dyno pull yielded 717rwhp/700rwtq w/ 16* timing/19psi/93 octane w/ Torco accellerator. Max fuel psi was set to 65psi, but was even more irratic from 4500rpm-up. The WOT rich (10.3 A/F) at 4500rpm and then WOT lean (13.7++) at 6000rpm was slightly worse.

Looking at all the logged data shows that the next step will have to be a change to FRPP 80lb/hr injectors to get the duty cycle, fuel pressure curve, etc all back into safe/efficient levels (this is the injector that Marv prefers to use). The VMP HPX MAF appears to be well within range for the airflow levels (only using 2/3's of the available capacity), but the stock Ford MAF with a Diablosport Mafia MAF-extender (set to #2 setting) will be switched in (this is the set-up Marv prefers to use) to get the MAF readings closer to max efficiency with less reserve (since not needed). The stock Ford MAF on it's own would be beyond range. The L&M 72mm TB is proving a bit tricky to dial in correctly! Expected power numbers should be 725-730rwhp/710-715rwtq w/ 17* timing/20psi/93 octane w/ Torco accellerator based on current dyno data. Much more power could be made with timing in the 19-22* range, but the closest 100 octane unleaded gas is an hour drive from my house...suprisingly, my trip/data readings show 17.4 mpg average (highway) with the latest tune, and I don't drive for MPG!!!

Will post further results when injectors/tune is finished...probably in the spring, as we're due for snow season any day now!!! I picked up and installed the FRPP 80lb/hr injectors and Mafia extender last week...with a temporary tune, the car does idle slightly rougher and does have a slight hesitation in revving (will need further tuning). Will post further results when I can get back to the dyno (Dyno conditions are optimal right now ))

UPDATE: January 24, 2012
After some conversations with Justin, it was decided to swap out; the FRPP 80lb/hr injectors for VMP-modded (47)-72lb/hr injectors, and the stock Ford MAF and Diablosport MAFia back to the VMP HPX MAF. Justin emailed a new VMP custom tune to get started. This week I will be datalogging some start/idle/step-rev/quick-rev data for Justin to dial the tune (injectors/fuel) in a bit. Also, I've decided to make the trip to Shelbyfest (Hermann,MO) this April 26-28, 2012 to have Justin do a real/live dyno tune for me!!!!! I can't wait to see what Justin can do, and to post those results!!!

(If your wondering why I still have the FRPP 113mm CAI instead of stepping up to a JLT127mm CAI, it's because I have a VaporSilver painted: FRPP strut bar, FRPP 113mm tube and air box, and Bangastang radiator shroud that all revolve around the FRPP 113mm CAI. If anyone has just the CJ 123mm MAF tube for a reasonable price, let me know...I could paint that VaporSilver and keep my other parts yet ))

UPDATE-Again: January 26, 2012
Got a great deal ($300) on a complete/almost new FRPP CJ 123mm CAI!! I decided to make sure that I've got everything finalized with this car before Justin dyno-tunes it at Shelbyfest!! NOW, I should be set..for good!

UPDATE-Again: March 13, 2012
The FRPP CJ 123mm MAF tube (with stock Ford sensor/meter) and VMP-modded 47/72lb injectors are now on the car. A starter tune from Justin (datalog-adjusted for idle and step-rev) has been loaded...and the engine really sounds and feels like a monster now!! Along with the awesome blower whine, the air intake has an amazing suction/whistle sound now too!! These cars are usually pretty sedate at idle...not anymore...it feels alive )) I'll have it back out on the road in the next two weeks. Justin will be dyno-tuning it in April at Shelbyfest in Missouri (hopefully he can add some dyno graphs to this posting after that)!!

UPDATE-FINAL: April 26, 2012
I made the trip to Hermann, MO to have Justin LIVE-dyno-tune my GT500. It was a FANTASTIC EXPERIENCE!!! The whole VMP team were great to work with and I met some GREAT GT500 owners there!!! The weather was NOT dyno friendly...around 90* and HOT!!! But, I did get a great tune from Justin and now my car has a safe 11.8 A/F ratio at WOT. Justin tuned the car for torque, and it's a monster now!! Even with TC on, the car torches the tires in 1st, 2nd, and 3rd at any speed (seems like for as long as you want too)...and even in 4th for a shorter burst (that's at 80+mph already).

I've attached a copy of Justin's dyno graph, just click on it to open it up ))

The VMP TVS is an amazingly efficient S/C!!! The VMP TVS is the ONLY SC that makes SQUARE RWHP & RWTQ numbers that I know of...and TORQUE IS KING on the streets!!!

Thanks to Justin/VMP for all your help!!! I can't thank the whole VMP team enough!!!

Kurt (Ready Go)

[Justin@VMP]

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