VAformula

iTrader: (8)

Who will port just a TB?

I'm buying used AI 200cc CNC heads for my 355 build and getting my intake ported to match them. I talked to AI and they won't port my TB. I was wondering if anyone else would do just the throttle body alone? I know some will do it with the intake.

96lt1m6

iTrader: (31)

There was a company that advertised on eBay to bore stock throttle bodies to 52mm and 54 mm I used to have a 54 from them and it worked AWESOME... other than that you can look forward to purchasing an aftermarket 52 or 58 for 300-500 bucks

nitrous2fast

iTrader: (2)

No real need to go to a larger TB with just a little H/C 355. save your money for something more substantial.

VAformula

iTrader: (8)

Would it really not matter? I know it takes a lot to NEED a bigger throttle body. But wouldn't I see good gains if I could get it at a good price? (I don't know what that price is, hence my questions). I also have 30 lb injectors I plan on putting on there.

F0x Slaughter

Why is everyone still asking this question.

A 355 with 100% VE at 8000 rpm consumes 810cfm.


Stock TPI/LT1 48mm Throttle Body w/o airfoil -- 783.0 cfm
(Reported from a flow test)

You are not going to achieve 100% VE. Its possible but unlikely.
So say you're at 90% VE and spin it to 7000rpm (LT1 PCM limit).

Thats 647cfm roughly. Even at 100% VE 7000rpm is 720cfm.

As you can see the stock TB will support you're goals.

VAformula

iTrader: (8)

Thank you!

F0x Slaughter

For future reference. Google Engine CFM Calculator, to find of the air consumption.

RamAir95TA

iTrader: (2)

A N/A engine will only breathe as much air as it needs. A 48mm is plenty.

F0x Slaughter

Agreed. Also if you open up the port you lose velocity. Velocity is what creates scavenging.

When the engine vacuum draws air in, if the velocity is higher it will help draw in more air, this is the principal on why a headers and x pipes work.

But there has to be a balance.