Is there a 3.1 expert in the house?

[3X00-Modified]

3-speed and 4-speed will be laggy if you never change the gear ratio... Thats the largest advantage that you guys feel when you go to a 5-speed. My 3.69 gearing in my 96 is far from laggy...

The 3400 crank is exactly the same part as the crank in the 3.1

3.1 intake would never fit the 3x00 heads even with port work the design is just completely different and that's also like feeding a fire hose with a garden hose, those intakes flow horribly.

[Travelor]

It's interesting to note what parts are interchangeable. My ultimate end goal for my GTU would be a turbo 3.1. Not feeling a 3x00 swap with trying to keep the old girl mostly stock. Plus I love the sound of the older v6's compared to the newer ones.

However, how would the newer parts (cranks for ex) in an actual turbo setup pushing some psi?

[3X00-Modified]

I don't think they really changed anything about it as the years went so it shouldn't make much of a difference... also I really haven't heard of anyone breaking a crank under boost. Just get some good H-beam rods from wot-tech and forged pistons.

[beretta]

The TGP 3.1 had forged crank and different cam. everything else i believe is the same. I looked into this couple years ago and was just going to buy a whole tgp motor i found but couldnt find a way to pick it up in time. Look around on tgp forums you might find a whole engine to drop in or at least the parts to get you started.

[Travelor]

Incorrect, as the block was hardened. Not sure about the heads offhand.

[3X00-Modified]

who is incorrect?

I found this on a W-body forum. What I was saying is I do not think there is any difference between a 3.1mpfi crank and the 3400 cranks, material wise.

Well I was hoping to wait and get this all on my web site, most of us are not too concerned as we already have it in our cars, but seems the info is spreading in it's need/interest, so for everyone, here is what I have found so far, please add anything I missed:

As for the engine and the McLaren Project, first off Dean is Vice President and Director of Facility Operations, great guy and a very sharp/smart man, we have talked on the phone, and met a few times at car events such as SAE MotorSport Conference and the SEMA Show, Wiley McCoy was there too, great guy who is also very sharp with a real passion for cars, and our/his baby. To repeat some of what was said before, but more so to put all the info in one place, here is what was done to the TGP engine and a little more, some components are used in other vehicle engines as well (see post below for casting numbers).

"Select engine components" meaning they were checked when taken from the parts bin for closer tolerances, that includes some of the engine items listed below:
Unique Vin V version of the VIN T Block, part number 10140528, stock VIN T Block is part number 10089656. Block, 20% Nickel content to improve strength, very small amount of tin for same.
(Yet unreleased at that time), head casting 10087511 and its larger, less defined heart shaped combustion chamber, with the deep dished 28cc/ml piston top to achieve the .1 drop in compression ratio to 8.8 (or 8.78 depending on what you read).
Forged Rods, these forged versions are unique to the 1989-90 TGP and TSTE only, part number 10070113, C-1037 Heat Treated Steel Forging, SAE 1050 Air Quenched Rod Caps.
Hardened Crank (Nitrided), Nodular Cast Iron with journal camfer/deep rolled fillets, casting 981 but this one IS unique to the 1989-1990 TGP and TSTE, worked on after starting as a 981 crank! Part number 10110549. Ion Nitrided/hardened depth of .02"-.03" raising surface hardness from 30-35 Rockwell C to 60 Rockwell C.
Mahle Autothermic Hypereutectic Pistons with Reinforcement Bar/Steel Strut to add strength to the top of the piston, 12% Silicone.
Stock 3.1L cam, as used in the 2.8L, 3.1L Vin T and Vin V.
Mellings Iron Body High-Volume Oil Pump.
Engine Oil Cooler as some Monte Z34s had, maybe others, unique water tap to regulate water to turbo, and fittings to plumb it in.
Coolant line take off welded on to provided for turbo water system return.
Oil tap port fitting added to block/metal braided hose for feed line to turbo.
Unique oil pan with turbo oil drain line fitting, and metal hose extension.
Unique Rear Exhaust Manifold to feed with other Exhaust Manifold the Turbo’s Exhaust/Turbine Side, constructed of cast nodular iron.
That damn OEM Crossover Pipe.
Larger 22 lb injectors.
Upgraded Fuel Pump taken from the Vette Parts Bin.
Garrett Water Cooled Turbo, T25 though smallish, at least one of the larger versions of it, for less lag problems though all lag is programmed into the chip, unplug the computer from controlling the boost and tire smoke in less than a second, way too much boost/spin to get a good launch, needs a bigger turbo for lag and traction control!
Boost control solenoid and lines.
ABS Unit Heat Sheild.
Unique Fuel Supply/Return Lines/Engine Bay Area, in front of ABS Unit.


Tranny setup is unique, larger tranny cooling lines and an aux tranny cooler in fender well.
Hardened Gears and Gear Carrier Set.
Additional Nested Accumulator Springs, other little changes to the tranny, some not listed until it's taken apart for inspection.
1898 rpm Stall Converter, not a High-Stall as the stock turbo is not large enough to warrant it!
Vacuum Line Check Valve/Bleeder at Modulator, Vacuum Line has internal restictor in-line to limit boost pressure and to allow check/bleed to fuction.

Larger (Blackstone) 3 Core Radiator that is plumbed for the larger tranny cooling lines.
Largest Electric Cooling Fan from the parts bin at the time, for main engine cooling.
Secondary/smaller cooling fan to assist engine cooling, condenser and intercooler air flow needs.
Blackstone Air-to-Air Intercooler.

Some other things but this should get out most of the info people are interested in.

Enjoy!

Jeff M

[Travelor]

I was telling the poster above me that it wasn't JUST the crank and cams that were different, but the block was hardened and I think the heads but i wasn't sure.

[3X00-Modified]

Ends up that the cam isn't even different tho....

[berettaz24]

i dont see why so many people hated the 2.8 and 3.1 the 2.8 cross fire injection v-6 i had in my camaro 86 model year was a bad little motha lol it would bark the tires into second gear with an automatic .. and the 3.1 engines were a beast stock i had a corsica and that thing would melt the tires and bury the speedo on the on ramp to the highway and it got 32 mpg .... i would trade the 3100 sfi for a 3.1 mpfi engine any day ....

[KFLO 93 GT]

As a guy who used to really love my 3.1 auto, and racing it... swapping to a 3400 and a 5 speed was the best mod ever.

[snowblindburd]

Jon(88_GTU) knows a lot about the 2.8/3.1's and modifying them as well. http://www.beretta.net/forum/memberlist ... ile&u=6139

On the subject of transmissions, I think either a Jon (3x00-Modified) inspired 4t60e or a 5 speed manual swap is next on my list.

As far as you swapping, there was an earlier version of the 4t60 that some of the Fiero guys swap to. I know literally nothing about transmissions and what would be the best bang for your buck, but here is some info about the transmissions themselves and on what they have to do to swap.

http://www.gmtuners.com/tech/440_4T60E_4T65E.htm

http://spacecoastfieros.com/tech/440-4T60/index.html