roughneck427

iTrader: (12)

Well i dynoed 387 RWHP and 376 RWTQ on my head and cam 355 and i have a stock TB my mods in my sig you guys think i should go with a 52mm or pull the intake and port it to 58mm and do some more port work to the intake manifold runners right now its only gasket matched.also i was going to add an underdrive pulley I'd like to break 400RWHP you think i can do it guys give me your opinions!!!!Thanks!!!

-PEPE-

iTrader: (10)

It will not give you 400rwhp going to a fully ported intake with a 58, maybe a few more ponies though, I'd go for it since you have heads/cam/fresh build/etc, in fact sounds like a nice setup you have going there.

Speed Density

iTrader: (38)

Very nice setup man. I cant wait to do a 355 or a 396!!!

Lethal Z

Well I can't speak for the 58mm but I just put on the 52mm and there's no difference that I can tell between it and the stock piece. I felt more of a difference putting on the cold air kit and the K&N.

buffman

iTrader: (9)

do a cold air intake, and before buying a bigger TB, measure the amount of vacuum the engine procduces at WOT. General rule for fuel injection if it's more than 2" you have a Intake restriction....

roughneck427

iTrader: (12)

yeah i have a K&N kit i even tried on the dyno with the cold air kit hooked up and disconnected it right at the mass air meter and lost 10 RWHP, so the K&N cold air kit is dyno proven with my own 2 eyes


I did a search on a few boards and there was mixed opinions on throttle bodys
im trying to figure out when the stock 48mm is maxed out as far as Flywheel or RWHP and if i would benifit on getting a larger one thats all guess ill just have to break down and buy one and try

buffman

iTrader: (9)

a lot of guys I've spoken too said they've made gains going to larger than stock TB when making over 300rwhp

Camaro Fan

iTrader: (1)

I've seen at least 2 or 3 seperate bolt on magazine articles over the years that tested a 52mm TB and got 10ish rwhp on a stock or very near stock LT1 (normal accepted results for other standard mods, don't see how it could be inaccurate...). I'm not sure I buy the conventional wisdom on these boards that they're worthless. Surely w/ a near 400rwhp setup you'd gain some...

roughneck427

iTrader: (12)

Yeah as far as the wisdom i agree but there are some people that are pretty sharp also i just take the opions and weed out the ones that i know are BS.But take the educated ones and use them.Thanks for the input!!!

SS MPSTR

iTrader: (1)

You know you need a larger TB when you have more than 1"-2" of vacuum being generated at wot, and you have ruled out a restriction in the exhaust.

blkchevyz

did a swap on an lt1 with bolt ons and the 305 cam. he gained 8-10 hp up the entire rpm band going from a stock to a 58.
and yes his intake port was matched for the 58

roughneck427

iTrader: (12)

Thats interesting now that i think of it when i was datalogging on the dyno i saw 93-98 KPA at my MAP sensor at WOT now i converted that to PSI which would be around 13-14 psi at WOT and i was running through an exhaust cutout headers and no CAT.Now would my MAP sensor reading be valid or should i just stick a vacum gauge on it?

Thats a real good way to figure out thanks!!!!

blkchevyz

13-14 would be more like 40 kpa

im running a 58 and i see about 90-92 kpa at 6000 rpms... im figuring my slp intake is a restriction now.

roughneck427

iTrader: (12)

Ahhh ok maybe what numbers i was using to convert KPA to psi were wrong that i did a google search on.So you say possible since my map reading was around 93-98 is that reading justified enough to upgrade to a larger TB?