engine specs

[Froggx]

if he's running sm2, I still don't see why he could't go to a bigger displacement, a supercharged 3.4 dohc would be awesome it sounds like his block is already prepped though and that's his motivation to keep it, which makes sense

[geoffinbc]

Yea lag would blow if you trying to tip on the gass out of a corner and leave the curve fast. It would be har to get that progressive action with a turbo.

But if you had a computer that could compensate for lag by dumping gas into the manifolds to keep the turbos spooled (like a rally car) then you would have it made

[TurboZ24]

I autocrossed mine before and all I Can tell you is that the turbo didn't cause issues, the amount of power did. I couldn't power through turns or push the gas unless the car was pointing straight, since it's got an open differential and just spun.

[Anonymous]

Wll I think he has to use a 2.8L block, becuz that is the original displacement of the car. Or maybe the limit is close the 2.8L. Either way, I don't think he can use bigger than a 2.8L. If so, I'd say a 3400 would be better, that way you'd have some low and midrange power. But a blown 3.4L TDC would definately give you some power throughout the rev range.

[Froggx]

well, I asked the local rule guru offhand what my fiero would be in with the turbo 3400 swap I'm doing and he told me sm2, I'm not sure if he understood I was changing my displacement or not though, but as a general rule if your car is modified enough that they don't know what to do with it, it's headed for sm2

[RacerX11]

Here is a site with rules for SCCA SOLO2 Street Mod classes: http://www.moutons.org/sccasolo/Rule..._modified.html If the rule doesn't specificaly allow for something, it ain't legal.

A Fiero in SM2 can have any GM engine, with forced induction, as long as it meets the displacement limits (4.0L for OHC, 5.0L for pushrod). Both the turbo 3400 or turbo TDC fall into this range. Engines above the displacement limits are allowed, however the minimum weights increase for these cars (up to 2500lbs for the Fiero). It is tough to get a SM2 Fiero much below 2500lbs within the rules, so its a moot point.

I'm not sure what kind of displacement/weight rules you must abide by for the 1/8mile racing, but you are going to need something bigger than a 2.8 (even with FI) to be competitive in SM2.

Marty

[sharkey]

well, with those rules, if money was no object, throw a 421" stroker smallblock in it, or get real wild with a 454" smallblock (yes they are possible, my dad built one) and stuff it in there. falls under 8.5l na, and its gonna have over 600hp easily on pump gas, and that fiero isnt gonna weight under 2500lbs even with an all aluminum v6. it would be one hell of a combo, the only thing would be keeping a tranny behind it.

seriously though, id say throw together a fairly healthy 2.8l ironhead, and go out and run it. learn the car, get the driving down, and have a bunch of fun. save your $$$ fopr next year, and drop some serious power into it to push to the limits of the class. we all know its gonna be hard to get a fiero down to 1900lbs, if not impossible. so why not go with a smallblock and aim for 2200lbs??? or even a boosted 3.4l dohc. even that would be a lethal combo.

or else, just get a 3.1l crank, some aftermarket forged 3.1l gen 2 pistons (try to get something rated for 9.5:1 compression, with ironheads, thatll be around 8.0:1) and do some serious porting, a cam, stainless valves, ect, with a blower on it, and get it around 18lbs boost. this will make a pretty good combo. all you will have to worry about then is getting the weight outa the car.

[Froggx]

you are going to need something bigger than a 2.8 (even with FI) to be competitive in SM2.

[Anonymous]

A turbo 3.4L DOHC would be competitive.

And with weight, a 88 Fiero Formula weighed in at just under 2400pbs. Witht he DOHC, that goes up a bit, but if you autoxing, you will also be cutting out a lot of other weight adding things. I'd say under 2500 with a 3.4L DOHC turbo wouldn't be that difficult, and could definately compete at the 1/8mi. With bore you can bring it up to 3.5L, and talk to Eagle and some other companies about strokers, I am.

[RacerX11]

Again, more misinformation from Aaron. The published weight for a '88 Formula is ~2680lbs.......a far cry from your "under 2400". Even the lightest stock Fiero, the '84, wasn't under 2400lbs. http://home.xnet.com/~paulv/MajorSpecs.htm

I would choose an LS1 or turbo Northstar over a turbo TDC for a SM2 autocrosser. You can get more usable power without any real weight penalty, and cheaper than custom internals for the TDC.

Marty

[Froggx]

Yeah, I was about to say, no fiero was that light...

Turbo N* or LS1 would rock, except I'm willing to bet the cost of the motor alone would be pushing the upper end of his budget, since he said he was on a small one after all. Don't forget the couple of thousand more needed for everything else to get in the car and make it work.

[Anonymous]

I was going off of what they told me from PFF.

And the reason I suggested a 3.4L over a N* or LS1 is the ease of the swap. A 3.4L TDC is a drop in, you don't need to really modify anything except for wiring.

[Froggx]

on my part I agree the tdc would be one of the more optimal swaps on a budget

[Cannonball]

lol, the turbo gets spooled with the 4.10's and you've left behind a massive cloud of smoke. Don't some of the fiero's with 4.9 swaps and getrags launch in 2nd on the strips because even 1st on that is too high?

Yes and no. There are some older guys who do state that the 1st is to low in most of the Fiero trannies for their V8s BUT the problem lies in the way they do things and not the gearing. You see, most guys who do a V8 in a Fiero don't take the time to really think abut the combo. These guys grew up with Camaros,stangs, etc where you are taught to use a very torquey low rpm stump pulling engine to get that hulk moving. Those cars weigh roughly 1k more than a Fiero and they also come with much higher geared trannies. That's the way the old school build most cars, big engine lots of low end torque moving a car in the 3400 and up LBs so that's what they're thinking when they jump into a Fiero V8 project. Then they find that they have a car that weighs significantly less, that doesn't need tons of torque to get it moving, and trannies that have yltra low first gears with low final drives as well and it's just a bad combo. What is needed is making your V8 with a little bit of a higher rpm range than usual is all and then it will fly. I'm talking only about the Chevy small block above. ( I could also mention a suspicion I have about the old guys not being able to shift quick enough too but that's just a theory I have )
I just had an older guy ask me about trans final drives because of this very thing at our club x-mas party in fact. He built a very torquey 406 small block chevy with tons of low end torque. Low and behold he's complaining about first gear being to low. What a shocker. You can easily make a SBC V8 rev even if it is a pushrod motor. You just have to do some thinking about your whole combo before you go writting checks is all. That's a good idea on any build, whether it's a Fiero or not though. At any rate, I bring this up because with a light car and low gears you obviously don't buid your engine the same way you would to push a heavy Camaro. You build it with some mid and top end in mind.

The 4.9 really is a low end torque motor so, in stock form you also need to think about a couple things; using the right Fiero trans and modding this engine to breath a little better. There are more and more stuff being done to these all the time.
As for 'going up in smoke' the traction issue isn't as bad as you might think. The Fiero, even with a huge ammount of torque, gets really good traction. The engine sits right over the rear drive wheels after all and the more powerful engine, although making more power, also weigh more which increases traction. Yes there's more power whch decreases traction now but, if you think about it, they kind of cancel each other out to a point. <---I did say to a point.
All of that is kind of off the topic of this thread but I had to answer what's been said.
The 4.10 trans is used behind the V6's all the time and it does provide more performance with it's lower gears. I have a friend with a swapped 3.4 pushrod motor with 4.10 trans in his 87 GT. The 3.4, being bigger, has more trouble winding up with the restrictive Fiero intakes but the combo still works quite well. Some porting or forced induction would help even more. Personally, I think the Getrag is the best choice for a Fiero. It has very low gears, a 5th gear for mileage, and it's the strongest trans they came with but this thread was about setting up for racing for a turbo set up so the lower geared 4.10 might be ideal for this instance and that's why I mentioned it.

Aaron; nobody on Pennocks ever told you the Formula weighed 2400 LBs. Formulas usually weigh in over 2600 LBs. By over I mean mid to high 2600's btw. A fully optioned auto Form. would probably even hit the low 27's even. The only Fieros that ever hit the 2400 marks were the 4cyls. The 84s were in the mid to high 2400's if I remember right.

[chucksterdesertdog]

For SM2, as much HP as you can get with as low rear end weight as possible.
The DOHC V-6 is VERY heavy and it is all up high in the car.
If I was going to try to make a car work with that much weight, I'd make the weight do something for me by putting in an alum LS1. (about 425#) The weight would at least be lower in the car also.

Late model 3400 would just start to be a player HP-wise with decent weight bias, then with with any kind of forced induction, be pretty decent in the class. You need 300+ HP to run with the fast dogs while keeping engine weight under 380 pounds. A coupe( not a heavy ol GT) with all legal weight savings MIGHT get down to 2450.

I run 500 pound/inch springs in my street fiero with no rear bar. Try to avoid a rear bar at all costs. They are a bandaid for street cars only and have no business being in a serious RWD Solo2 car that has to go around tight corners.


By the way, anyone know just how bad the duribilty is for small journal 2.8 cranks ?