Ravant

Alright - for the longest time, I've had this 1985 Fiero 2m4 sitting on the side of my house, begging for attention. She served her purposes well in bone stock form in embarrassing several local ricers in autocross situations, but now the transmission and radiator are shot, and frankly, I'm bored with a pathetic 90 horsepower and 130 ft-lbs of torque with a 4,000 RPM peak. I'm looking into taking this Fiero out of the land of the slow, and going all out with it, both mechanically and in terms of looks.

I'm sure, this being an LS1 performance board, no one really cares about my ricer aspirations of a whole new body for the car beyond the fact that I'm looking to drop the drag coefficient and kill that 120 pounds of lift the car generates at 100 MPH. (An LS1 in the car would undoubtedly be able to push the car past 100, so stability is a definite requirement.) So - as to not really bore anyone with the bodily aspects of the car, I figured I'd get right into the technical aspects of what I intend to do, at least engine wise. (Just so you know, I've already taken measures in terms of the suspension, brakes, among other safety/handling/stability related parts of the vehicle to make sure dropping an LS1 into this car isn't an instant death-wish.)

I plan on taking an LS1, preferably used to keep costs low, and mating it to a built-up GM F40 6-speed transaxle and going through a set of 17x10 wheels in the rear. (Hopefully some moderately sticky street tires.) It goes without saying, these engines are rated to 350 crank horse, so I'm not going to ask about stock LS1's. What I am going to ask, however, is the following:

1) About how much power should I expect to lose through the GM F40 transmission and included differential? Would it be safe to say 15% is a fair estimate? Or am I giving this driveline too much credit, and I should expect more losses?

2) About how much money does it usually take to put these engines to the 465-ish crank horsepower mark, assuming I've already got custom built headers for my application (kinda necessary when mounting transversely in a compact engine compartment like that of the Fiero.) as well as a full 3" exhaust system including cats?

3) Basically, what I'm trying to get at is, I'd like to have 400 horsepower at the wheel, with a plateau of a powerband, kicking in as low as possible, holding out to as high as possible. I don't care about peak power production, this car is not being built for drag racing. I'm building an autocrosser, and I want to be able to hit anywhere between say 2k and 5k on the tach, and still have a respectable amount of power on tap. I don't want to downshift, have the needle drop to say, 2100, and have to roll through the powerband for two seconds while I wait for the engine's peak torque to give me a further push. This may not be 100% realistic, so, I guess my question is, what's the closest amount of power I can get to the 400 horsepower mark, while still maintaining a broad, flat plateau of power? Don't forget, I'm stuck with a transverse mount here, so sudden, peaky torque curves are going to simply tear the whole driveline to shreds without a second look.

4) Lastly, and this is strictly a question of opinions, I fully intend to measure for exact results later on, what kind of fuel efficiency should I expect out of a 2800 pound car equipped with the LS1 with a 6th gear ratio of 0.71:1 and a final drive of 3.55:1?

Thanks in advance for any responses to the questions in my painstakingly long thread.

jfman

iTrader: (6)

To make low low rpm power, stick with a stock motor. Every cammed and ported motor I have driven are peakier than stock. Maybe you can stroke it. 350hp in the fiero should be enough to get you in trouble anyway. BTW" that's just my opinion.

Ravant

Well - if I could get away with just lengthening the powerband without actually making it peaky/dangerous to the transmission, that would be ideal. The longer, the better. Doesn't necessarily have to be specific points. I just figured 2-5 was more realistic than, say, 4-7 out of an LS1. But - thanks for the input. I may end up leaving the LS1 stock, but I would like to gauge any kind of mods for the engine while it's still out of the car. Once it goes in, even changing the spark plugs is going to be a huge production.

cherryelky305

iTrader: (2)

I see what you mean, however without fully understanding what you intend to do with the car, If it were my car, I would keep the LS1 stock. Its got plenty of power for that car. Just my opinion. Hopfully someone else will chime in on the best path for more power and your goals. Good luck, and this has been done before, so at least you have a few resources.

Ravant

Yeah - V8Archie's got a kit to get the LS1 in the Fiero now, and a kit to get the F40 in as well. Planning on getting both to do the swap. Requires a bit of modification to the sub-frame and such, but I've done quite a few other swaps in the past where such was necessary, so it shouldn't be too hard for me. There's a strong chance I'm going to leave the LS1 stock because I've got a semi-limited budget on the car, so if I run out of cash restoring the interior (it's pretty bad. I got the car for under $700 bucks.), among other parts of the car, then there won't be many funds for continued increased power output. I'm mostly just trying to find theoretical limits as to where I could take the car, say, in two years, when I'm bored with a "mere" 350 horse.

Grr

iTrader: (2)

Well if you want simple and just spend the money once, get a LS2 or LS6 right away. Trust me the LS2 in that car would be retarded. The small bump in displacement to 6.0l really made the torque come in fast and hard, and with your headers and exhaust, with a decent tune you would already be looking at 440hp with stock everything. and 400+ torque for a couple thousand rpm. Also the F40 6 speed is actually pretty efficient and 15% is a very probably # with it. you might even be able to crack a 14% out of it with some good oil. I know exactly what you want to do with that car i think, and you wont be disappointed with a stock LS2 i guarantee it.
Gary

Ravant

The LS2 would be one hell of a powerplant for the car, but realistically speaking, 1) I dunno if the Camaro/Firebird oil-pan works on it, and that's the only pan that fits my application, and 2) Could I seriously get one in running condition for under 3k? Because I've seen some pretty cheap LS1's around, and that's what made me decide on a V8 instead of a seriously built turbo Ecotec LE5.

V8sounds

iTrader: (1)

A stock ls1 with like a 224/224 .581/.581 cam would definatly make big power from like 2.5K all the way out to probably 6.5K.

blackhawk400

iTrader: (1)

I'm pretty sure the Camaro/Firebird pan fit, maybe some other guys could back me up on that, but from what I know, it would work.

Good luck on finding an LS2 for under 3k though. Maybe the new 6.2 truck motor? I think its aluminum, but probably not available used from a yard yet.

Good choice though on using an LS motor on the car. The Ecotec would be great but it would take a lot to make it capable of equalling the LS motors

QSPres

iTrader: (15)

Any pan from any LS-x based motor will fit. Just like the Pontiacs of old, all the LS-x blocks are the same outer dimensions..

You'll need at least the oil pump pickup tube from whatever pan you swap to and possibly the dipstick assembly and windage tray as well. In my experience, the CTS-V windage tray and the truck trays are exactly the same (both are the long style), but I know the F-body is a short style. They all bolt in place of each other.

bczee

iTrader: (12)

I would say that the GTO (front Slump) and the Bat Wing Vette pans would not be good choices. IMO the F-Body or Vette LS2 would be the way to go.. Truck would be a no good due to the deep slump.
The Fiero is very low to the ground and staying with the shorter sump pan would be a better. (I have a 87 Fiero and still kick around the idea for the next project, or the 71 Nova or the 48 Ford truck as the next projects?? to many choices..!).

Ravant

So - in my research, I've come across another potential problem. With the suspension setup I'm planning on using, and the tires/wheel width, and the lighter hood/decklid, I'm told it wouldn't be uncommon to see upwards of 1.1 lateral g's on average around turns. Knowing how engines work, and how oil likes to slosh around, especially in transverse mounting situations, would it be prudent/worth it to invest in dry-sump systems instead of the oil pan? Also - I'm not sure I like where the stock water pump sits (I'd have to have some stuff in one of the wheel-wells.)... anyone know of any remote-mount electric pumps I could use instead? If not, I'll just fabricate a protective box, not a big deal. But - I'd like the install to look as natural as possible, so if someone looked under the deck-lid, "Wow, I didn't know they came with a V8 option in '85." Considering the LSx is as light as the stock iron-block V6 that originally came in these cars... yay.

bczee

iTrader: (12)

For a remote water pump system, you might try looking into the Hi-Pro Boat applications. Some of them use remote pump systems. I have seen a few but have not looked into it.. We just using the normal belt driven OEM water pump on my brothers boat.

If you look in Dec 07 Chevy High Performance mag.. page 46... they are using on the steup on a project BBC.

Ravant

Thanks for the heads up, I'll look into it during my tireless searches. I figure, the more info I have at my disposal going into this build, the better off I'll be on the way out. Not going to make it like my '99 Monte build, where I went in blind and learned on the fly. That was stupid.

chevtech23

Have you seen the water pump for the FWD 5.3? It moves the pulley off to the side and up, neatly packaged. I would imagine that alot of the 5.3 W car parts would work for your application.

Ravant

I thought about that too, but the 5.3's got that electronic throttle body thing, and trying to fabricate a pedal cluster out of parts from the W-body as well as original Fiero parts for the clutch make it a harrowing thought for a swap. If I was planning on using a 4T65HD transmission, I'd be all over that, and it would be a relatively simple swap, but I'm hoping to use the F40 transmission. Would that water pump work on an LS1? I've had three people suggest using it now, but I don't wanna get it and try it and realize, "Oh, well, that didn't fit. Back to the drawing board!" Know what I mean?

chevtech23

I would assume using that water pump would require the use of all of the other accessories from the fwd 5.3 or coming up with a different pulley to bring it in line with the other accessories. As far as physically bolting to the block, it would bolt to any of the LsX blocks

Grr

iTrader: (2)

You should look for a complete 5.3 minus the trans. you can convert to cable throttle in a matter of minutes, its not a problem. disable ETC in the tune along with most of the trans stuff and youll be just a few bolts away from completing the swap. As oil pan and mount mod have all been covered on the fiero sites.
Gary

Ravant

I thought the LS4 was prone to disliking anything other than auto mated to it? I mean - not that I'm against the engine, and the higher water pump would be a benefit to using it, but I've been told time and again, the LS1 would be easier, at least electronically, to get into the car without a hitch. I'll definitely look into the LS4, though. Any thoughts on pricing though?

Ravant

Alright - I don't mean to give myself a bump here, but upon further investigation, I found that I'm going to need roughly 480 crank horsepower to reach my wheel horsepower goal. I've already got the basics down, a custom intake, and a set of headers, which go to a pair of magnaflow high-flow cats, then out the back of the car (no room to mount mufflers, may find small race mufflers or something to soften the blow slightly).

Granted, there will be some ECU tuning involved, but I'm not going to do that until the engine is complete (all the mods are added) so I can get the most out of my tuning.

But beyond these three basics, what can I do to have this roughly 480 crank horsepower but still maintain a broad, flat powerband? A new cam is a definite, but what brand/grind should I be looking for? And I'm also looking to do head work and some work on the valvetrain (springs, valves, lightweight pushrods, etc.). What should I be looking for in terms of brands/specs?

Lastly, after the above is completed, what would be my best course of action from here?