I'm doing a 383ci in my lt1 camaro!
i'm going to be running with Longtubes, Fully Ported and polish heads and ported intake manfold. also abiger MAF
Which size of TB should i get 58 or 52?
i'm at 4,000ft and going to be running right around 11to1comp
thanks
cw wardIII

 

58mm AS&M. If you don't have the $$, get your stock one ported by Nomad.

 

I think that AS&M also makes a 54mm version, maybe that would help solve your dilemma, the best of both worlds.

 

Definately a 58mm, IMO.

 

I did a lot of research on this prior to mine going in a month ago. You'd be fine with a 52mm.

 

Read this thread on sizing throttle bodies and let me know if you still feel fine about running a 52mm with a stroker...

http://web.camaross.com/forums/showt...hreadid=189363

 

this has always interested me. We have personally had a 52mm and a 58 mm dynoed back to back on a friends 383 and he actually lost 4rwhp with the bigger 58 back to back. I personally went with the 52 and it works great

 

Doesnt AS&M make a single blade TB for LT1s... because i saw a pic of one once and damn i would get that, that thing looked like it sucked in more air than a freakin black hole, it was awesome.

 

Yes... the monoblade. Over $500 though I had one up until a month or so ago and it was PRETTY A bud of mine kept bugging me about it not doing me any good sitting on my shelf so I finally gave in and it is on his car now. His car is mostly stock and it runs good with that throttle body (no hp numbers but no issues with idle or anything like that).

 

Thanks! This is one of the few times I've seen actual hp numbers posted. I presume his intake was ported to 58mm?

I'm going to do one of these as well and will remember the results you saw and see if I can duplicate them.

 

That is interesting! I'd love to see the data from those runs. Since you did the 58mm right after, was the car run with higher coolant temps? That can lose 10 hp right off the bat. Was the A/F ratio identical?

Not trying to bust your *****, but I'd really like to know if your data is legit. Could change the way we size throttle bodies?

 

Yeah... it kinda violates the laws of fluid flow and friction losses. Considering the engine is fuel injected, it may not help much to use a larger throttle body but it shouldn't hurt though either Will be interesting to see if similar results are repeatable... for example, dyno the 52 then immediately the 58. Allow car to cool down. Dyno 58 then immediately the 52. If the 58 is lower again that would make me scratch my noggin a bit

On the flip side though, a guy in Orlando dyno'd 10rwhp higher with a 58mm throttle body over a 48mm on a mostly stock LT1. I believe he had a Flowmaster and K&N but that was it.

 

Exactly my thoughts! Given a proper tune, and with test conditions COMPLETELY IDENTICAL, a modded 383 should have gained from the 58mm. I think...

 

http://www.worldisround.com/articles/12201/photo70.html