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TGP vs. 3.4DOHC


THe_DeTAiL3R

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I love w-bodies and want to have a faster one.

 

I know the 3.4s can be damn fast, but I also know they cost a lot on repairs and are a PITA to work on - an engine I just don't want to deal with.

The TGP has good old 3.1 and is fast car too, but how are they on maintenance? Do they cost much to keep up? Are they a whole lot different than a 3.1 n/a?

Also, do they come in 5-speed? How many (%) came with them?

 

Ultimatly, if the TGP is as reliable and cost efficient as a regular 3.1 and comes in a 5-speed, that would be the perfect car for me. :wink:

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There are NO Production TGP's made with 5 speeds, they are all automatics. But there are about 10 people on these boards who have done a 5 speed swap and it seems like they all love them. Even if u cant find a TGP that has a 5 speed swap i would still buy one. U just cant beat the price on one and u will shit once u see all the stuff they come with. The standard features on a TGP are what people are paying 5000 extra for on todays cars. They are just all around AWESOME!

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TGP vs. DOHC in terms of maintenance is probably the same. DOHC has alternators and timing belts. TGP has crossovers and brake boosters. The DOHC isnt that hard to work on once you get into it. Get that big old plenum off and its just like every other motor.

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I have no problem with DOHC's but one thing u have to remember is...The TGP comes from the factory with a turbo. So all of the internals are forged, the computer knows what boost is...the transmission is meant to handle boost. What I am getting at is, the motor and all of its components are meant to take a beating. Turbo's put a lot of stress on everything and a TGP is already set to handle it, just something to remember if u are someone who likes to go fast, ALL THE TIME LoL. :D

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Cost is the same basically. How much is a crossover from Jeff M? A few hundred? Thats how much an alternator is.... How much is a brake booster for the TGP? I thought I read $500.... the timing belt costs less than that if you do it yourself.

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I have no problem with DOHC's but one thing u have to remember is...The TGP comes from the factory with a turbo. So all of the internals are forged, the computer knows what boost is...the transmission is meant to handle boost. What I am getting at is, the motor and all of its components are meant to take a beating. Turbo's put a lot of stress on everything and a TGP is already set to handle it, just something to remember if u are someone who likes to go fast, ALL THE TIME LoL. :D

 

I was thinking that the DOHC and TGP both had the same crank and rods. As for which is better pick the one you like to drive as they will probably both end up costing about the same in the long run.

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same price in the long run eh?

 

Probably. You'll replace the ABS module (is that what it is that always goes wrong, something that costs $500) on the TGP as well as the crossover pipe. They got fairly strong tranny's but they will still go out and the turbo will need to be rebuilt sooner or later.

 

The DOHC you got the alternator going out once every 2-3 years and timing belt maintenance. Tranny is a problem if you don't have a 5spd and the motor can be finicky at times. Some things can be a pain to work on but it is not impossible, most people just chicken out. (I can have the plenum, turbo, exhaust to the cat, intake system, lower intake, and all the misc stuff out in 2 hours, course i have had way too much practice :( )

 

One plus the TGP has is that its boosted, a boosted motor will almost always be cheaper and easier to modify.

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Are you able to do a 3x00 top end swap onto a TGP? Lots of people to it to n/a 3.1s.

 

No...the GEN III 3100 heads won't bolt up to the TGP's exhaust manifolds.

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Are you able to do a 3x00 top end swap onto a TGP? Lots of people to it to n/a 3.1s.

 

No...the GEN III 3100 heads won't bolt up to the TGP's exhaust manifolds.

 

That's very easily remedied...all you have to do is "d" shape the ports in the manifolds.

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Are you able to do a 3x00 top end swap onto a TGP? Lots of people to it to n/a 3.1s.

 

No...the GEN III 3100 heads won't bolt up to the TGP's exhaust manifolds.

 

That's very easily remedied...all you have to do is "d" shape the ports in the manifolds.

 

Or just leave the manifold cirlcular and heads D-shaped, as long as the circle completely fits over the D

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Let’s not forget the exhaust manifold gasket, use the D-Port one to scribe out the shape of what the TGP exhaust manifold needs. But then there is the TGP lower intake that will not mate up to the Gen III heads as they are raised, serious welding to make things work here. Swapping the new intakes will take care of that problem but there is some serious work to get everything hooked back up and working again such as TB, EGR, Fuel lines and more, then since we changed the intake runner lengths (shorter/less torquey down low), will now need to swap out the stock cam to a 3100 style/upgraded 3100 style to match the new breathing characteristics of the new intakes, then all new VE tables in the chip (at least) since air flow has changed all over the place. More thoughts than someone probably wanted but it’s not that someone cannot do it.

 

Jeff M

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i think you should TRY to find a tgp because in my mind i think there are more things that u can can do to them then a dohc...and like said earily the engine in a tgp is meant to handlethe power and the boost of a turboand lots of other things that u can think of to do to the car.....but good luck on finding one that isn't a sh*t box that u don't have to fix up just to get it running like it can from the factory.these cars are very hard to find

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...and like said earily the engine in a tgp is meant to handlethe power and the boost of a turboand lots of other things that u can think of to do to the car

 

The DOHC and TGP crank share the same casting, the rods are identicle and the blocks are from the same design. That leaves pistons and heads that are different. Also the DOHC has a pretty decent windage tray that acts as a light duty stud girdle.

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He can be Candian JustGotPassed.

 

You can do as much to the DOHC or more compared to the TGP. The DOHC block should actually be stronger than the gen 2 pushrod block, since it has the lifter valley filled in with metal. It was reinforced pretty well anyway. The cams can be timed to whatever you want, which would be a nice experiment for boost (or get a regrind on top of that). There are intakes and heads that can be swapped

 

The gen 3 top end swap on a TGP would be well worth the effort, as it would make much better use of the forced induction with its better flowing intakes and heads. Honestly, If I owned a TGP I wouldn't even bother with the gen 2 top end at all. Total crap IMO. I would also use the gen 3 pistons or go with forged lower compression (yes, gen 3 raises compression but 9.6:1 is perfectly fine for boost).

 

But I don't own a TGP, I own a 5 speed DOHC. I think that alone will tell you which I prefer.

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