96ta

ask yourself an honest question if the car is going to be used for autoxing how much interior do you really need?

96ta

perhaps an ls2 or ls6 cam with ls2 heads or ls6 heads

Ravant

Enough of an interior to tell me everything that the engine's doing, to be comfortable enough to drive under harsh driving conditions for 10+ hours, and enough to tell me down to the 0.01 lateral G, how hard I'm pushing. (Just so I can learn the car's upper limits, and use them frequently.) Beyond that? Not much.

As for the LS2/6 heads/cam, would they really be able to get me up to 480 crank horse?

1CAMWNDR

iTrader: (21)

Some mild port work, .035" mill, 2.02 and 1.57 valves, good valve job and a 224° .581" 112° LSA cam and a good tune will get you great torque and 410+ hp at the wheels. Oh, LS6 intake and port and polished throttle body.
Check the dyno section for some different combos and their results.

Ravant

Thanks for the info. That's a lot less work than the LE5 turbo I was planning, so that's great news! I'll have to peek at the dyno section to see the whole powerband for a full understanding of what's going on though.

ryanvv355

iTrader: (17)

480 crank HP on a LS1 is cam and bolt on territory, most 6spd F-bodies make around 350rwhp with bolt-ons and tuning. I think you will be right where you need to be with only a cam swap

Lowerit

What magical Tranny are you running that isn't gonna shatter? I have a northstar fiero 5spd right now.. and with all that HP are you ripping out the factory (Shitty) suspension and replacing it? Are you going to complete in EMod?....


J.McCreery
66 Corvair , 04 Ls1 , porsche 930 tranny.
86 Fiero GT , 32V northstar

1CAMWNDR

iTrader: (21)

There ya go.

FIEROPHREK

Remember to build up that tranny or you'll be asking those ricer boys for a ride to a tow station. Seriously though you should be able to met your horsepower goals easily with the LS1 or LS6. A cam ,a good set of heads, and a tune would probably get you there, as long as you have a good exhaust setup.

Red89GTA

Going to the Dyno section would be a good idea as previously stated. Also, call up some cam manufacturers (Crane, Comp and Futral are board sponsers), or one of the many shops. I'm sure they would be able to point you in the right direction/suggest something that maybe you hadn't considered.

Sounds like a sweet project, 400whp fiero, build for autoXing, nice. Where do you live, gotta make sure not to be in the same event/class as you when mine is up and running

Ravant

The GM F40 (MU9) transmission can hold up very well, assuming you use the right clutch. The weak link actually becomes the rear axle setup, and if I remember correctly, Rodney Dickman makes some seriously beefed up bearings for the rear that's even used on the 509 WHP notchback that's floating around the 'net. Beyond that, it should be fine, especially considering the 4t65HD is handling roughly the same amount of torque from the L67 W-bodies that are in the 12's, approaching 11's and are staying reliable (the differential is a different story.), the MU9 should have no problems with 390-410 ft-lbs of torque (at the wheel, not sure of the input strength. Just add roughly 15%.) GM's claiming the MU9 is stronger than the 4T65HD, so - it only logically follows that it'll handle a middle amount of power coming from an LS1. If the W-body guys are pushing the L67 and turbo L36's beyond what I'm planning to push out of my N/A LS1 with little to no reliability issues, why should I worry about the F40?

As for the suspension setup, I'm converting the rear to the updated 1988 geometry by replacing the engine cradle and using one of the many adapter kits available on the 'net. I'm also using Koni adjustable coilover struts in the rear with a 475lb spring rate, with 425 on the front using a fully redesigned slalom suspension setup including similar coil-overs (this is assuming I can get in touch with the proprietor of Held Motorsports).

In order to stop this car, I'm using either 12 or 13" brake kits with 4-piston calipers up front and 2-piston in the rear, biasing the strengths roughly 70% front, 30% rear, with a variable bias controller that will change +- 10% on the front and rear, depending on road/track conditions, etc.

As for actually competing? Not sure. I'm building the car for my own personal satisfaction and pleasure, to know I have the power of an 8-cylinder symphony at my right foot's command.

Fierophreak, the F40's have no documented abnormal issue with the LS1/2 swaps yet (at least that I've found), and a friend of mine's sitting on an un-modded LS1 in his '88 GT, and it's his daily driver. He had to replace his clutch after 27,000 miles last week, but that's pretty much the norm for even the stock V6 and Getrag 282 that come in the car. I plan on using a beefier clutch and some better axles, but as for the internals themselves, it genuinely shouldn't be a problem.

Red89GTA, I'm living around the Eastern Long Island area. We used to have a nice autocross track, and even a decent drag facility around here way back when, but they're all shut down now. My closest drag strip is Englishtown, and their road course still isn't ready for the public, IIRC, so my next closest option with a decent challenge is Watkins Glen International.

In my time over in the dyno section, I saw a pretty nice dyno sheet, roughly resembling what I'd ideally like for a power/torque curve. It was Ceissus' Camaro with the MS4 cam, LS6 intake, etc. Not sure if that's the direction I'm going to take yet, for I still have to deal with one or two other issues first. (Finding the length of an accessory belt I'll need when I eliminate the power steering pump, and again even shorter if I eliminate the water pump in favor of an electric system. Figuring out how I'm going to keep enough back-pressure in the exhaust even though I have extremely limited space to do so, and figuring out how to mount a set of mufflers, even though I lack the space and still want to keep my trunk.)

jfman

iTrader: (6)

sounds like you got it all figured out. Now all you need to do is rob a few banks

Ravant

Yeah - it's not going to be cheap. Suspension and brakes alone are going to be close to $6k.

ShaneSmith

how about a LQ9 with l92 heads L76 intake/ with comp 918's and a cam around ~220/~220 ~580/~580

Ferretts

if you want tourqe and not too peaking i would take a look at some AFR 205s and a G5-X1 or G5-X2. I personally would go with the X2 because it will give better power up top while still kickin your *** into gear when your down low, especially coupled with the AFRs... That should net you a little above 400 on a REALLY REALLY safe tune. I would expect around 420 with a rock solid tune that is very drivable and reliable. Or if you wanna be cool you could always slap a maggie 112 on there. instant torque!

Ravant

Thanks for the suggestion, Shane, but I'm pretty much dead-set on the LS1, I've got a good deal I really can't refuse for the engine, wiring harness, and ECU out of a 'vette, and am more likely than not, going to take it.

As for the tuning, Ferretts, thanks. I'll look into everything you stated, does sound a bit intriguing. Now when you say down low, where in the RPM range are we talking? Are we talking pre or post-3,000 RPM?

ShaneSmith

oooh. i didnt catch u already had a deal on an ls1. i just threw in that idea.

Ravant

That's 'cause I didn't throw it. I looked into the LQ9, not a bad engine, but it's not ideal.

Lowerit

I wish you luck. I autocrossed my Fiero for 10 years , finally gave up on it and ran a E36M3 , RS america and a 997S.

The fiero is a great car...tis no autocross car though... Running an 88 rear cradle on an earlier front is the best bet. They are heavy cars.

The guy withthe 509WHP has a trailer Queen , it's never been to the strip and sure as hell hasn't been to an autocross. The 509 WHP was on the bottle.

I have all the tricks , Koni's revalved , coilovers ..poly , big brakes.. at the end of the day it's a very lethargic handling car..

Appreciate it for what it is , don't throw away acres of cash trying to build an autocross car. in Emod you will get slaughtered by guys like Tamandili


I was the guy who started the fieor racing list years ago with George and Doug Chase.

As for the auto... yeah it's strong , but at the cost of 280Lbs... nasty... Chris moore of northstar Fame weighed in his 87 GT with a northstar and an auto at 3300lbs.

like I sai d, it's a fun car , I love mine ...but autocrossing a Fiero and expecting to be competitive where it's classed is a sure fire way to waste money.

Flame away!

Ravant

The question is, at least for the fronts, what did you change? Just the struts, or everything? Suspension geometry and track width, on top of tire width all make a difference. I've seen a lot of people try to autocross these vehicles on stock fronts with nothing more than a set of coil-overs, expecting greatness. I've seen a lot of people only put little more than $3k into the suspension expecting 1.1+ average lateral G's. The point of building this car is getting a car that handles and accelerates on par with a C6 Z06 for less money. It's not an impossible, or overly expensive goal. I'm told it's been done before, and with the multiple discounts I'm getting, I wouldn't be hard-pressed to believe that it's an achievable goal. In terms of autocross, especially the class I'd be sitting in, it's not about being the best in class for me. It's about being able to make the runs and compete against myself. The other options for vehicles, such as a Miata, just aren't comperable.

Don't forget, an LS1 doesn't weigh nearly as much as a 32v DOHC Northstar motor. Nor does the 6-speed MU9 weigh nearly as much as even a 4t60 automatic.

As for being heavy? It's close to 500 pounds less than a Corvette C6 Z06 with an LS1 and MU9 6-speed installed. Cutting out the un-needed sheet metal from parts of the frame, while also moving to fiberglass for the body should remove a halfway decent amount of weight. I fully expect race-weight to be little under 2900 pounds with me in it. The tubular suspension components are lighter than stock, offsetting the increased weight of the larger brake components. Next to the cars I'm going to end up competing with, the RX-7, any F-body, it's nimble. Weight isn't everything, and when leaving the stock 2.5 lock-to-lock steering box, the steering is slightly sluggish, but changing to a 1.9 lock-to-lock steering box will offer quick, responsive, tight handling characteristics that rival that of the Miata. With the V8, it's not going to be in a class of Ariel Atom-weighted vehicles. And if I decided on the LE5 or LNF ecotec motor for a swap, it would be possible to cut the car's race weight including a 160-pound driver down to under 2750 pounds, which puts it just under a modified 3rd-gen MR-2. The reason I'm not doing the I4 swap just yet is because I'm planning on getting another Fiero, and waiting for the transverse LNF to be released as a stock setup from GM. Right now, the LNF is still a longitudinal motor and because of its turbo setup, is a real pain in the butt to get into a transverse mount.