3.4 Sports Car Project Finished

[BillS]

I have owned a Fiero from the early 1990s and have converted it first to a Miller Woods bolt-on turbo on a stock 2.8, and later to a modified 3.2 with knock sensing for use with higher pressure, going whole hog on the engine with specially made forged low compression pistons, custom cam etc.

So when I picked up a rebodied MG (my other focus) a year and a half ago, the natural thought was to install a GM V-6-60, although not turbo. I did think of using a remote mount turbo on it, but concluded that with maybe 2000 lbs. to drag around a modified 3.4 would suffice.

Could have gone 3400 but had a bunch of stuff for Fiero that I could use, so opted for the cast iron version.

Rebuilt the engine with larger 62 mm throttle body, Crane 272 cam, modified Fiero tubular headers, did all the head work and intake work to remove the usual bottlenecks, and left it at that. I was curious what sort of power would result, starting with the stock 160 BHP. Figured between 180 and 200 - is that realistic?

I kept the injection, although run by an OBD 1 ECM instead of bolting on a carb as too many people do when sticking these engines into other cars, and it runs beautifully.

Pics, if you are interested at:

http://www.rhodo.citymax.com/i/non-rhodo/March07a.jpg

http://www.rhodo.citymax.com/i/non-rhodo/rear.jpg

http://www.rhodo.citymax.com/i/non-rhodo/DIS2.jpg

I machined off the GM stuff on the upper plenum and had the MG placed there - it has already confused some people. The base car is a 1957 MGA, BTW.

[IsaacHayes]

MG? GM? Hahah kind of goes together. Nice clean setup! I like it! Looks great. That's a big radiator! Did you have to bore out the intake manifold for the 62mm TB?

What transmission are you using?
I bet it moves pretty good and sounds nice! It sure does look awesome.

[BillS]

MG? GM? Hahah kind of goes together. Nice clean setup! I like it! Looks great. That's a big radiator! Did you have to bore out the intake manifold for the 62mm TB?

What transmission are you using?
I bet it moves pretty good and sounds nice! It sure does look awesome.

The radiator is an alloy crossflow racing rad from Afco - weighs 8 pounds, and has welded seems (none of the clamped garbage that comes apart on you).

I forgive you for asking if I bored the intake throat. Yes, I've been building race cars for 30 years and I did bore it to match - in fact because of uneven casting it broke through in one place and that's why I painted the whole upper plenum instead of polishing it, which would have shown the Devcon patch....:-) I understand why you ask, though as I have also seen people that buy stuff and just stick it on without any thought to matching everything. The lower intake is matched to the heads as are the exhaust manifolds. Because it isn't a race engine I decided not to bother pinning the manifolds to the heads.

Transmission is a T-5 out of a V8 Camaro (better ratios than the really low V-6 trans had), and a 3.9 diff ratio which means excellent acceleration.

Exhaust is single 2.5" into a Magnaflow straight through muffler and a Pacesetter splitter/resonator. Sounds really good, but then I am prejudiced!

The performance is probably equivalent to what a Fiero GT would give you with around 270 BHP, although in terms of acceleration from a standing start, the mid engined car would have better traction because of the superior weight transfer. On a road course, it would be hard to choose. I am running 215 x 60 15 Yokos on 6" rims and these chassis handle very well. Here is one I have been racing for the last 3 decades.

[treeZ24]

thats sure a sleek looking body.

i'll bet its a pleasure to drive once you hit the powerband

[IsaacHayes]

Right, I figured you knew better than to just bolt it on, but I wasn't sure of the stock opening of the 3.4, or if it had enough material to bore out to 62. I've never seen one up close. I'm used to FWD intakes. What throttle body is the 62 BTW?

FieroGT's didn't have anywhere near 270 crank horsepower. A modified one perhaps, as those are popular to mod, but are usually engine swaps or turbos.

That exhaust is a nice setup. No restrictions there! I take it the T-5 needed an adapter machined to bolt up to the 60*?

[BillS]

Right, I figured you knew better than to just bolt it on, but I wasn't sure of the stock opening of the 3.4, or if it had enough material to bore out to 62. I've never seen one up close. I'm used to FWD intakes. What throttle body is the 62 BTW?

FieroGT's didn't have anywhere near 270 crank horsepower. A modified one perhaps, as those are popular to mod, but are usually engine swaps or turbos.

That exhaust is a nice setup. No restrictions there! I take it the T-5 needed an adapter machined to bolt up to the 60*?

No, I wasn't saying a Fiero DID have 270 BHP, I just said IF it did, you'd get equivalent power to weight ratio to this little beast. (In fact my Fiero SHOULD have that sort of power - blown at 13 psi, but I've never dynoed it).

The only way to take a stock 3.4 throttle body out to 62 mm is to bore and sleeve it, which is what they did. At least that should no longer be a bottleneck.

The T-5 bolts right up to a Camaro V-6 bellhousing which bolts to the motor. Only trick is that the V8 trans used a fine spline input shaft, but the 94/95 V6 Camaro did too, so I was able to find a clutch. Made up a juice clutch slave and bracket and had a custom driveshaft made up to mate the trans to the MG diff.

If you are interested in some of the gory details see

http://www.rhodo.citymax.com/Jamaican.html

(yeah, yeah, it is on a gardening site I run - just ignore the flowers....)

[IsaacHayes]

Ah got ya. I will check out the site! Beautiful car!

[kflo 93 gt]

Cool build, I love the body on it too, looks like a little Jag. I bet it gets around nicely with the 3.4 and the low weight, the gory details wouldn't load up for me... so I was kind of curious what you have under it for suspension seeing as how you're a track racer. That's something I've really thought about getting into more, autocross is fun but it's only cones, and you're by yourself. I've done a couple open track days and I love that, so I can only imagine under competitive situations. sorry for the mini thread hijack.

[BillS]

I was kind of curious what you have under it for suspension seeing as how you're a track racer. That's something I've really thought about getting into more, autocross is fun but it's only cones, and you're by yourself. I've done a couple open track days and I love that, so I can only imagine under competitive situations. sorry for the mini thread hijack.

I am using Dayton 15 x 6" wheels, Yoko AVS ES100 tires, decambered front end, 550 lb. lowered front springs, 3/4" front bar, solid bushings, and a 3.9 diff, open, not posi.

I have found this to be a nice street and slalom configuration. I run more aggressive suspension on my race car - 950 lb. front springs, lowered roll centres, Panhard, Quaiffe LSD etc.