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2007 Grand Prix GT Mod results

TwinV6GTP

New member
Just finished modding my Daily Driver 2007 Grand Prix GT.
It was a Christmas gift to myself !

Went from 100% stock to:

Since it's a 2007 used a 2005 ECM by Overkill.
That worked well and improved the car's 0-60mph by .5 seconds and made it more fun the drive.
It took away the KR I had on 91 when I was 100% stock.

Then installed 3.0" pulley
and installed a Methanol Injection kit with a very large jet.
Made an intake tube, welded some bungs.

Obviously since the tune wasn't made for that pulley and a methanol kit which enrich a lot, it ran really bad with those 2 mods (misfire and knock)
I then went into HP tuners to edit the fueling table. I left the timing map alone. That completely fixed it, with only 1 tune, it is perfectly tuned (safe).
There is zero knock to be found.

Better yet, since it's very cold here, I run 15 psi of boost + with the 3.0" pulley and the logs show up to 49 lbs per min. Huge power. The car pulls very hard.
On dry pavement, I can roll into the throttle in 2nd gear and light the tires up all through the gear.
Really impressed with the power, the cold weather + 16 deg of timing + 15 psi of boost on a Gen V is a lot of fun.

My other 1997 GTP ran 12.9 @ 107 mph and only had 39 lbs/min of airflow. This car has 10 more lbs/min which means it makes nearly 90 HP more and with a larger pulley.

Just wanted to share.
 
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Managed to get the 3.0 pulley and a lot of power on pump and meth with no cooler with this genv

Got 49lbs min airflow

No knock

10 lbs min more than my other 12.9 sec gtp

To me those are results

As for drag time its winter so none so far


Sent from my GT-P5210 using Tapatalk
 
Today did some more runs. 49lbs/min was at 5000rpm.
At 6000 rpm it is 58lbs/min. Injectors are more than 100% duty.
The very large methanol jet with high methanol % is keeping it at 11.0 A/F ratio.
I still don't have traction, so I can't compare performance.
Hopefully the road will clear up, it seems like it snowed every day for the past few weeks here.

Today we made a downpipe and deleted the cat/resonator. Love the sound.
Kept the factory mufflers for now, they don't look too restrictive for a factory muffler.

I'm still running stock plugs at stock gap, stock manifolds, no intercooler 3.0" pulley, Meth injection and 94 pump gas and no KR.
 
Just measured performance:

Stock was
6.5 0-60mph on dry pavement
7.0 sec on wet roads (which is 95% of the conditions in winter here)

Now:
5.4 seconds 0-60 mph on wet roads (1.6 second quicker)
my guess it will run high 4s 0-60mph on dry pavement. Not bad on winter tires.
It's quick, no doubt about it. It will run 12s 1/4 mile on regular winter tires.

On a sad note, we just finished tuning my employee's Turbo AWD talon (big turbo 28 psi of boost)
We ran 4.0 0-60mph on wet pavement, got to love AWD and 500HP !
 


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