3.1 turbo questions

[montess408]

i was looking for info on the 3.1 turbo motor and cant real find anything
do they have forged pistons stock ?
is the cam a diffrent one than the stock n/a 3.1 ?
what is the limits of the stock turbo ?
are the heads and intake the same as the n/a 3.1 ?

thanks guys

[Superdave]

i was looking for info on the 3.1 turbo motor and cant real find anything
do they have forged pistons stock ?
is the cam a diffrent one than the stock n/a 3.1 ?
what is the limits of the stock turbo ?
are the heads and intake the same as the n/a 3.1 ?

thanks guys

no, the pistons are cast
Same cam
10-12PSI.. maybe? the T25 is pretty small, alot of people upgrade
Yes, the entire top end is the same aside from the writing on the plenum.

the SCR change is rumored to be lower due to either a slight deck height increase, slightly larger dish in the pistons, or a GM tech fudging the numbers.

[montess408]

so there is nothing special about it then
hypertec pistons should hold up better then stock one then right ?

[1988GTU]

Everything is the same.
Compare these specs to the tgp and you'll find that they are the same.


People have pushed 18psi through the Gen2, headgaskets become the limiting factor before the lower end starts to let go. However, you should be at about +350hp/tq before you start to see stuff blowing/falling apart. Don't be surprised if you go through a few transmissions/parts getting to that number.

[kuntzie]

i have ran over 18 psi on my 3.1 turbo, dynoed 302 whp and 409 wtq on a rough tune and hitting fuel cut at about 3800 rpms and im going for over 400 when i go in nex week (still on the stock botom end)

[montess408]

so you dont really need forged pistons to boost then ? i know it's probley better but if your pushing 18psi on cast pistons would'nt hypertec pistons hold up to the same or more ??

[Superdave]

it's all in the tune...

[1QUICKHATCH]

no, the pistons are cast
Same cam
10-12PSI.. maybe? the T25 is pretty small, alot of people upgrade
Yes, the entire top end is the same aside from the writing on the plenum.

the SCR change is rumored to be lower due to either a slight deck height increase, slightly larger dish in the pistons, or a GM tech fudging the numbers.

the turbo 3.1 heads have different chambers! they look a little more like a 3500 chamber

[Superdave]

the turbo 3.1 heads have different chambers! they look a little more like a 3500 chamber

the N/A 3.1 heads have a similar shape as the 3500 as well.. they all have the "fastburn" shape...

i have some heads from a 3.1 in the garage if you'd like to see a pic

[1QUICKHATCH]

the N/A 3.1 heads have a similar shape as the 3500 as well.. they all have the "fastburn" shape...

i have some heads from a 3.1 in the garage if you'd like to see a pic

they are not the same as the N/A heads. the chambers are rounded off more. I will try to get pics in a few weeks. the turbo heads flowed a few CFM better too, but that was most likely just the casting.

[GutlessSupreme]

The turbo heads not turbo specific and are also on some N/As. In fact, my TGP and TSTE had different heads too.

Supposedly, TGP crankshafts and blocks are stronger than N/As, but nobody really knows one way or the other.

However, TGP pistons ARE different. They are cast, but they have a reinforcing band in the piston for strength. It's inside the casting around the circumference of the piston. I don't think the N/A pistons have this, but I know for a fact that turbo pistons have this and have pics of it in mangled form

http://www.w-body.com/forum/index.php?topic=12387.0

those are all the supposed differences between N/A 3.1s and turbo 3.1s.