i see alot of people here have an after mrkt TB, is the extra 10mm of incoming air really worth the $300? what HP would i gain, i cant see more then 15 rwhp realistically.... any comments?

 

Its my opinion that a larger aftermarket TB would not be worth it on a stock setup - never.
However, I think it is necessary once you find yourself smack in the middle of souping up your car and the extra air flow provided is NECESSARY and no longer optional.

So figure out how much you want to mod, and if your car in the future will need a larger TB.

 

GM uses the stock 48mm TB on it's big block ramjet which makes
510 HP, you decide.

 

i am at 500 (498) hp at the flywheel, people tell me i should buy a new 58mm tb, i just dont think it will help all that much. i have a 383 TPI w/ an intercooled procharger @12psi, i would rather spend the extra $300+ on something else, i just wanted to know if some one had some great hp improvement stories......

 

gflo383,
The 58mm Throttle Body will help a little. Expect .1-.2 tenths in the qtr improvement if your horsepower is what you say it is. But at your level...that would be a big improvement to me.

Have you run your car on a dyno? What times are you getting now? fuel pressure? injector sizes? throttle body airfoil?
Just curious. A 383 with a procharger must be awesome!

 

At that Power level, the 48mm TB may become a restriction, but then again in a boosted Motor its not really the factor that it would be in a NA setup.

Your sure as hell alot more in need of a 52 or 58 mm TB than Most of the people who have them, However

 

I say toss the TB idea and test out some large tube tpi runners so I know if theyre worth it! =D

Seriously tho, for 300 bones you could buy any of a number of good mods that far outweigh a larger TB in terms of real power gains on a 383.

383 TPI w/ 12 pounds of boost - i'd be afraid of you at the staging lights =9

 

Damn...
Just read another one of your posts. I'd like to have your problems...2.2 60' time roasting slicks
I'd see about investing in some suspension mods.
...Keep us updated on whatever you do.

 

for normal driving you'll probably loose some of the throttle repsonse... but at the track you'll see a decent improvement as previously stated.. I would just switch back to the 48mm for street duty.

zroc

 

I must correct myself, GM uses a 58mm TB on the 502 big block
to make 510hp. If you are making 500 ponies with a 48mm TB
then the 58mm TB would be a logical next step. I say spend the
dough, put the 58mm on and see what she does with the added
air flow. I bet she possibly picks up a few dozen more horses.

 

I Say, you Go for the bigger TB and also a K&N Cone filter that bolts right to the TB...I cost 50 Bucks but with the Bigger TB It will increase POSSIBLE airflow...But The pistons only pull in so much air. And with TPI its not like it will evaporate Fuel any better. Maybe... You should Port & Polish Plenum..Bigger Runners and then get the bigger TB.. But I would Port the plenum and the stock runners and see what that will do..Also get the KN Filter anyway and get rid of the HUGE airbox. But im only 16 so i dont got the Bucks For the awsome #*%$. So K&N....Wait....Then Port&Polish....wait.... then bigger TB....

 

Good idea. Lets take off the supercharger and stick a cone filter on the throttle body.

Porting and polishing has nowhere near the effect on a boosted car that it does on a N/A car.

 

hahahahahahaha i was waiting for that JZA )