Tearing apart my '90 3.1 turbo, and the top end seems far inferior to the Fiero 2.8 The throttle body is much smaller, the intake runners seem narrower, and longer. The valves are splayed in the head, I dont know if that makes a diffrence or not. But the whole thing just looks weaker

Im really thinking I should bolt the Fiero top end on this thing, and comments? I could care less about appearing stock and all, Im just going for performance

bump

Wonder how much of your boost gets eaten by airflow restriction?

BTW, I had a video once of a guy with a early 90's 3.1 Lumina with a turbo running 12's. Pretty sure he built a 3.1 N/A motor and added the turbo. It was really pretty funny to watch a plain, boxy 90's lumina fill half the track with smoke on the burn out... then proceed to roar down the track fast enough to embarrass some of the quickest production cars ever made...

Wonder what you can do with a TGP motor in a Fiero?

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Chris

Blue 1987 GT Getrag 5 speed, 1" lowering springs, 225 50R16 rims and tires, Fiero Store 9 3/4" HD clutch (Halfway through a 3.4L TDC Swap!) Silver 1986 2m4 THM 125c automatic (Current commuter)
Black 1985 2m4 SE Isuzu 5 speed (no paperwork)

I used a 3.1 in mine with a DS1 turbo. It redlined over 7K, pulled hard all the way there. Used stock Fiero intake, TB and exhaust manifolds. The 3.1 wasnt stock. Many of my local club members can vouch that its top end didnt suck.........

[This message has been edited by rogergarrison (edited 03-24-2005).]

I'm assuming if he's talking about splayed valves, this is the 3.1 with aluminum heads, right? They actually flow better, although I don't know if they are more durable than the cast iron Fiero heads.

When I said top end, I meant Physicaly. What im getting at here is, has anyone compared the heads/ intake/ and throttle body of the two and determined which is better. Does anyone have any flow data on them?

The splayed valves have better combustion and if it is a turbo engine out of a 90 Grand Prix Turbo there is a very minor difference in the compression ratio between stock aluminum head 3.1 vs turbo engine. The main differences were in the guts which were stouter. That engine put out about 205 horse but it was hooked to a beefed up 4 speed auto/overdrive tranny. If you are running a 3 speed auto fiero tranny you probably are running out of steam at high speed.

Even the standard 3.1 aluminum head engine is better than the 2.8 iron head engine used in the Fiero. I think it was rated at 165 hp. Only problem you cant run a Fiero intake with the aluminum heads. If you have a 3.1 that has aluminum heads you can't swap to the cast iron heads as it will screw up your compression big time. The pistons have a deeper dished out area.

Is it a GP turbo engine you have or just an aftermarket unit on a 3.1?

Thinking about a turbo package from a GP with intercooler on one of my Fieros. Would like to know how you swapped this.

[This message has been edited by Mike Murphy (edited 03-24-2005).]

I think I mis wrote that. I have never driven the engine. But in taking it apart the intake and especialy the throttle body look much smaller. I was thinking that the Fiero intakes and throttle body look like they would flow a lot better, and am interested to see if anyone agrees

bump for more input

Never saw the Lumina van, but vids of a 4-cylinder '89 Caravan here http://www.turbovan.net/van.html
He really put the Mustangs and Camaros in their place. LOL

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Fiero Fiesta - July 24, 2005 - Calgary, Alberta <--- click this LINK

3.4L S/C 87 GT www.fierosound.com
2002/2003/2004 World of Wheels Winner &
Multiple IASCA Stereo Award Winner

You might check and see if the Truleo intake will work with your application.

quote Originally posted by 86GT3.4DOHC: I think I mis wrote that. I have never driven the engine. But in taking it apart the intake and especialy the throttle body look much smaller. I was thinking that the Fiero intakes and throttle body look like they would flow a lot better, and am interested to see if anyone agrees

Size of the ports isn't the only determinant of power efficiency. If it were, then port design and combustion chamber design would be irrelevant.

JazzMan

Thats my problem. Do I go with the 2.8 top end that has bigger intake ports, slightly shorter runners and a much bigger throttle body, or with the 3.1 that seems to have slightly better heads. Or should I go to the 3100 top end ?!? I wish someone had flow data on these parts

Well the more I look at it, I guess it might be ok. If its properly portmatchced it should flow ok. Im still real worried about the throttle body which is kinda tiny. Does anyone know of bigger throttle bodys that will bolt to the 3.1 intake