75mm TB (split from For Sale thread)

[SappySE107]

Your dyno comparison is for a 4.6l V8 DOHC engine that has a 75mm stock TB (and went to 78.6mm, not 80). I saw your throttlebodies on ebay. You think a 225 hp 3400 is going to be able to use a 75mm TB? ROFL!

Can't split threads or id move it so you could sell your 75mm TBs to people that don't check the pushrod general section see this information. Sorry.

[ryan.hess]

When I did a back to back comparison of stock 75mm and an 80mm throttle body on my northstar, I gained 6hp and 15lb-ft of torque from 3000-6500. The whole torque curve just shifted up, it was unreal. I'd bet the 3900 would have similar gains if the intake could be opened up. The 3500 could probably gain some too, but you would be decreasing the throttle's dynamic range unless you had a high RPM screamer or something.

But we're getting off topic. 15 posts and 3 of them have to do with the original post. If you guys want to discuss throttle body sizes and pros/cons, post a new thread.

[SappySE107]

You have to look at other factors though, like the intake manifold design. How are you going to possibly use a 75mm TB on a 65mm opening? Why have such a large hole feeding a much smaller hole. Stock 3500 is 65 and stock 3900 is 70mm. Stock 3400 is 56mm. I think GM figured out the TB sizes for the best power/powerband for their engines finally.

Id love to see more comparisons between TB sizes for boosted engines as well.

[ryan.hess]

I would not recommend this throttle body if you're making less than 225hp. 75mm is used on a 250hp aurora from the factory, so a little bit less hp is probably okay.

[ihatemygrandamg]

I refuse to sell an adapter to put a 70+mm TB on a 3400/3500. Its a bad idea and I won't help you guys get shitty throttle feel and WOT well before the plate is all the way open. No one listens to me it seems but whatever.

I agree. No need for that much bigger.

[patgizz]

I refuse to sell an adapter to put a 70+mm TB on a 3400/3500. Its a bad idea and I won't help you guys get shitty throttle feel and WOT well before the plate is all the way open. No one listens to me it seems but whatever.

hahaha.

[SappySE107]

I refuse to sell an adapter to put a 70+mm TB on a 3400/3500. Its a bad idea and I won't help you guys get shitty throttle feel and WOT well before the plate is all the way open. No one listens to me it seems but whatever.

[ihatemygrandamg]

Damn I thought 65mm might be a bit overkill unless your boosted or cammed. 75mm??? Not for us 3400 guys, thats 19mm over stock lol

[SappySE107]

[Originally from the following thread... http://60degreev6.com/showthread.php?t=34483]


Who would put a 75mm TB on a 3400?