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New owner of 2007 Grand Prix GT want to know if HP tuners is compatible

TwinV6GTP

TwinV6GTP

New member
I see in HP tuners supported vehicule list stops at 2005 for the Grand Prix.
But I see ECMs available from vendors.
I had great luck doing my own tune on my old GTP running 12.9 on street tires @ 107 mph with very basic mods.
I'd really be bummed out if I couldn't make any adjustments myself.

Any insight, I've searched the forums and can't find much info on that year model.
Btw it is 3.8 S/C.





 


Its a special edition aswell with them fancy rims and rear valance.


But to any the question, no you can not tune 06 and 07 pcm's.

The only way to tune them is to buy a 04 or 05 NON comp-g computer and swap it in. And if you do that, you can tune it but the gas gauge will read backwards.
 
Fivefingerdeathpunch said:
Its a special edition aswell with them fancy rims and rear valance.


But to any the question, no you can not tune 06 and 07 pcm's.

The only way to tune them is to buy a 04 or 05 NON comp-g computer and swap it in. And if you do that, you can tune it but the gas gauge will read backwards.
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Yeah, I love it, I think it's georgous inside and out. The photos don't do justice, that color is very nice in the sun and I love the ground effect and rear air damn.
It's almost exotic looking from the back.

I did see that in another forum. But I also read there is a tuner near Toronto (close to me) that says his PCM will not affect the gas gauge or cause any issues.
He says it's for the 2007.

Only problem is the way I tuned my old GTP was very different than what you would normally do. I used more methanol injection than a typical install and use HP tuners to take fuel away.
That resulted in a lot of power on 91 octane without knock/KR and even more with some AV gas when running the 2.6 pulley without an intercooler.
In other words I will be very limited not being able to tune myself
I hope a tuner will be available by this summer.
 
There is a guy named Will at Overkill that can tune those year cars, but its a canned tune you can't change anything after you get it. He somehow cracked them or something and figured out the gas gauge issue.

Easy way to do it yourself is to buy an 04-05 pcm.
 
Doing it myself with an 04-05 PCM would mean a backward working gas gauge and I heard a few other dash issues, is that right ?
Also is there any performance shift mode for a GT? Mine does not have the Tapshift and the car shifts really early, similar to my GTP when not using performance shift mode.
 
Not sure on other issues, only heard of the gas gauge.


The car has a "performace shift" per say but no tap shift or buttons. Just kinda picture it as a throttle based % type thing, I think it will use those tables in the pcm when it feels that you've given it enough gas along with a few other thing that need to line up in a row, to give you the quicker shifts/higher line pressure. Otherwise they design cars now to be as smooth as possible and be most fuel friendly, likely why it just feels/is shifting sooner.
 


Car would be easily .5 to .75 second quicker to 60 mph with just torque management toned down and shift 400rpm higher


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Will from Overkill Motorsports can tune the car and everything will work the way it should. However he protects his hard work so no one else can go in and mess with it. I had an in car tune done by him on my 2007 GP GT. Well worth it if your close to him.
 
savage93 said:
Will from Overkill Motorsports can tune the car and everything will work the way it should. However he protects his hard work so no one else can go in and mess with it. I had an in car tune done by him on my 2007 GP GT. Well worth it if your close to him.
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I'm close. this is going to be my daily driver so a set tune isn't that bad of a deal as long as it works well with no KR.
Is there any way to reach him by phone. I sent him an email but not answer yet.

I can't stand the 5500 rpm 1st to 2nd shift, right when the car starts to pull good.

I am using a GPS performance meter and this car is a pathetic 6.51 sec 0-60mph simply because of 5500 rpm shifts.
My 500$ GTP beater car ran a best of 5.00 0-60mph and averages 5.5s with just my own basic tune (reduced Torque management 6300rpm shifts, harder shifts).
Everything else is stock. This is in winter (very cold air).
I'm 1.51 seconds faster to 60 mph with my old 2000 GTP.
My 97 GTP with a 2.8 pulley and methanol injection ran 4.7 0-60mph even quicker (also ran 12.9 1/4 mile)
 
Stock valvetrain shouldnt be pushed past 5700-5800 rpms in my mind. Kinda why shift points are 5400 (motor spins to 5600) and speeds of 45 mph for 1-2 shift.
 


Fivefingerdeathpunch said:
Stock valvetrain shouldnt be pushed past 5700-5800 rpms in my mind. Kinda why shift points are 5400 (motor spins to 5600) and speeds of 45 mph for 1-2 shift.
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I've got 2 GTPs I've done this to so far, same tune. One I paid 1500$ with 102 000 miles engine with a 2.8 pulley then a 2.6 pulley 6200rpm shifts (6300rpm actual shift). It runs very hard and has a 100% stock engine/trans/headers except for exhaust, pulley, tune and Methanol injection. Then I took my 500$ parts car (150 000 miles) and made it run very hard to, but it's winter and even the stock pulley with 6200rpm shift point and 6300rpm shift gained a solid full second 0-60mph. There is zero KR with this as well and runs 5.0 flat 0-60mph huge gain from stock. That's on winter tires too. Both these show no valve float at that RPM. Of course I wouldn't recommend this to others it is very high rev for a factory drivetrain.
I do have 2 spare engines/trans so I can take more risk than most with rewards to go with it :)

Finally ran 6.2 sec 0-60mph on my stock 2007 GT in 11F weather. It took a perfect smooth spinless launch to achieve this. Just the right amount of throttle tip in.
 
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Quick note about this car...
So I've got the aeroforce scan gauge on it. 3 deg of KR bone stock on 91 octane and it comes up quickly and stays on.
Took Torco octane booster to drop it to zero and occasional 1 deg KR.
pretty crazy for a stock car in cold temps. I can just imagine the guys putting 87 in it in the heat of summer.
These engine have to be tough to be bullet proof even when stock.
 
I've seen the naturally aspirated engines run to over 500,000km with minimal maintenance. Actually the only reason they didn't keep driving the car was because the body was falling off.
 
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