Surprised me too when I heard it so I measured, sure enough:


(It moved to 53mm when I set it down, but it was 52mm)

[This message has been edited by Hudini (edited 06-11-2007).]

quote Originally posted by Hudini: Either buy a generic 62mm throttle body and add a compatible IAC and TPS, or get a junkyard 62mm with a compatible IAC and TPS and splice those wires to the Fiero wires.

The link I provided above for the Grand Am bored version uses the same TPS and IAC as the Fiero. It plugs right into the Fiero V-6 harness.
If you want a quick "junkyard" fix, The stock Grand Am is 58mm.

quote Originally posted by Oreif: The link I provided above for the Grand Am bored version uses the same TPS and IAC as the Fiero. It plugs right into the Fiero V-6 harness.

That sounds easier than I'd originally thought. I suspect a 62mm RSM throttle body from pfyc.com, and on a Trueleo intake, is in my car's future.

However, given the OVAL shape of one side of that 62mm RSM throttle body, can it be connected to the circular opening of the Fiero's black rubber air intake tube that normally connects to the Fiero V-6's STOCK throttle body?

I ask because I'd like to preserve the car's air cleaner canister, its cold air induction system, and if possible, NOT use a jerry-rigged aluminum-foil-covered air intake tube set-up like those I've sometimes seen on PFF.

recently over at 60degreev6.com its been discovered that a gm 4.3l vortec (from a 98 blazer) tb is about 70mm and can be easiely mated to a 3500 manifold. i dont know about mounting the tps and iac, but i bought a 4.3 tb, manifold and accessories from ebay yesterday. ill find out in a few days what it takes to mount it up and if the iac and tps work, and linkages. 70mm is good for 8k rpm on my 3.4 with a heavy port n polish, crane 272, 1.6 roller rockers, trueleo package and more. or at least i think 70mm will be enough

WARNING WARNING WARNING

RSM (actually the company that bought them) no longer carry the two bolt GA throttle body. All they have it the four bolt for the 4 cylinder. It would require modifying the linkage, (operates backward to the Fiero) and building an adapter plate. I just ordered one, and it's going to cost me to return it.

Chuck

im using a stock 2003 mustang gt 4.6 throttle body....65mm from the factory, they are cheap and plentiful. im using an iac adaptor from electromotive to handle the idle air and making an adaptor plate from 1/2'' aluminum. all in all im paying less then $150 for a 65mm tb.

quote Originally posted by fierochild: WARNING WARNING WARNING RSM (actually the company that bought them) no longer carry the two bolt GA throttle body. All they have it the four bolt for the 4 cylinder. It would require modifying the linkage, (operates backward to the Fiero) Chuck

Uh-oh!

Carelessly, I never noticed before in regard to my (uninstalled) four-bolt RSM 62mm throttle body that it "operates backward" relative to the stock Fiero throttle body, but now I see exactly what you mean.

With the stock Fiero throttle body, its throttle linkage and the upper half of its butterfly ordinarily would have to pivot AWAY from my engine when giving the Fiero more throttle.

In contrast, with my (uninstalled) RSM throttle body, its throttle linkage and the upper half of its butterfly ordinarily would have to pivot TOWARD my engine when giving the Fiero more throttle.

Is there a straightforward fix for this problem with this 62mm RSM throttle body that doesn't turn it into an overly complicated "Rube Goldberg" device?