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Looking to Buy an 04+ GTP

S

Stricken

New member
Hello all,

I'm about to go look at an '04 GTP Comp G. It's a one owner car with maintenance records and fresh tires. It has 156k on the clock and a dent in the rear passenger door/quarter panel, so I'm picking it up cheap. From the ad, everything seems to be in working order. The guy is selling it for his mom, so I think this is a classic old-lady-mobile. Before I put the money down, what should I be checking out on the car? Any common issues? These seem to be stout power trains, so I'm not too worried about the mileage.

Next, I'm familiar with blower motors from way back when my Lightning still had the Heaton on it, so.... what are the quickest/cheapest mods to get into the 12's? :D Deep into the 12's? :th_biggrin2:
(Nitrous doesn't count)
(Also, I have two M112's just begging to be put to work again, and a very good dyno tuner)
 


You'll spend double the value of the car to reach deep 12's. The transmission alone will cost more than the car is worth. Jump straight to a turbo kit if you are serious otherwise you'll be spening money on headers, intercooler, tiny tiny pulley, camshaft swap etc etc to reach that goal. Then tuning, wideband, fuel pump, 50-60lb injectors, switch to E85.


There is a general common problems thread around here some place. Oil leaks and intake gasket failures on common, if it has the black plastic intake gaskets with dexcool coolant still, it's a waiting game for them to fail. Transmissions are problem prone at that mileage. Regular suspension related items like control arm bushings and wheel bearings.
 
this is not the same 2800 in a ford if thats what you mean. only thing in common is th em90.

and 12's, you need a turbo.
 
Fivefingerdeathpunch said:
You'll spend double the value of the car to reach deep 12's. The transmission alone will cost more than the car is worth. Jump straight to a turbo kit if you are serious otherwise you'll be spening money on headers, intercooler, tiny tiny pulley, camshaft swap etc etc to reach that goal. Then tuning, wideband, fuel pump, 50-60lb injectors, switch to E85.


There is a general common problems thread around here some place. Oil leaks and intake gasket failures on common, if it has the black plastic intake gaskets with dexcool coolant still, it's a waiting game for them to fail. Transmissions are problem prone at that mileage. Regular suspension related items like control arm bushings and wheel bearings.
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Really? It takes $5k to reach the 12's? I was thinking intercooler, DP, pulley, injectors (if needed), and a tune would put me in the neighborhood.

I can fix gaskets and bushings easily enough. If the transmission tends to go out around this mileage, I might be concerned...

Scottydoggs said:
this is not the same 2800 in a ford if thats what you mean. only thing in common is th em90.

and 12's, you need a turbo.
Click to expand...

Are you referring to the engine in the Thunderbirds? I meant the Lightning engine. It uses an M112.
 
It's a mid 14's car stock if you are lucky.

You'll max the injectors past a 3.4 pulley range, which only adds maybe 40whp. Factory front manifold is terrible, downpipe is small and that's why we upgrade to headers. You'd be talking like 2.8 to 3.0 pulley or so to make enough power and at point you'd want to run 93 octane with meth injection or E85 to keep cylinder temps down to prevent it from blowing up.

It's not easy or cheap to make these heavy fwd cars fast. You'll be at a greater risk of breaking transmissions past the 250-260whp mark, mainly because the torque will be well over 300 ft lbs and stock input shaft ain't got time for that.
 
Stricken said:
If the transmission tends to go out around this mileage, I might be concerned.
Click to expand...
The T465E trans has some ridiculously low service interval. I want to say it's around 90k, maybe someone can help me out there. Just to keep it from getting err.."slippy" maybe?..anyway, use a Trans-Go shift kit (google "t456e trans go") and change the filter. I've been reading most guys use a bottle of lucas after the procedure. Here's a link to the default guide on the forums ~ http://www.grandprixforums.net/thre...ransGo-Shift-Kit-4T65E-Very-Detailed-Pictures

It uses an M112
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The M112 has been fitted to this engine. Go over to the members rides and there's at least one whipple-equipped example too. I've read there's a larger kit that fits an M122 to the 3800, but I don't even know if that guy is still around or many he came up with. I did a bit of research about superchargers recently.
 
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Great car if you can get it cheap enough. If you want to get it to the low 12s like said above you will need to put a lot of money in it. I just put a ZZP trans in my 04 comp G and it was over $4500 for the trans alone. I installed it. Beefing up the trans is a must if you want to go that fast for long.
 
On top of what was mentioned a couple things to look for;
Check the rocker panels, undercar, and radiator support for extreme rust. Also look at the rear strut towers for rust on the trunk area. The previous generation had a bad problem with this. Not so much this generation but I have seen rust through on the 04+. If you live in a southern state or one that doesn't salt then you probably don't need to worry about that.

On test drive make sure you get it nice and hot and make a lot of stop and go starts. These transmissions tend to slip at that mileage. Something with the friction material covering solenoids and sensors causing this.

Check lower intake gaskets, look for any other major leaks. Oil pan gaskets are a bit of a pain to replace on these cars but no problem for someone with some mechanical skill.
 
rickisrad said:
Great car if you can get it cheap enough. If you want to get it to the low 12s like said above you will need to put a lot of money in it. I just put a ZZP trans in my 04 comp G and it was over $4500 for the trans alone. I installed it. Beefing up the trans is a must if you want to go that fast for long.
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$4500 for a trans? Damn dude zzp must have seen you coming or something.

And you had to install it??? Jesus.

For the OP, e85, cam, headers, tiny pulley. 12's with traction.

Where's Tyler to spew his crap about his old car? Someone send him this thread!
 
LOL, yeah I guess so. I got all the options, input shaft, single chain, pump shaft, 245mm converter etc...... yeah Its still a lot of money but I've seen nothing but horror stories from "local" rebuilders and I wanted it done right. The trans is definitely worth more than the car, but I wanted to have a transmission to handle all future mods.
 


I was flip flopping between the two. I'm sort of regretting my decision as I am chasing a knocking putting it in gear. :(
 
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