big.turbo.daddy

Whats a good throttle body to run on a ls vtec turbo engine. It has about 400 hp

turbomaniac

the bigger the better, there is no rule

OneBadTurboCRV

Not necessarily as you can ruin engine characteristics by going too big. There actually kind of is a rule - at least the same size as your charge piping to prevent restriction.

As far as the OP's build a stock throttle body will work just fine.

big.turbo.daddy

So if I do change my throttle body it just has to be the same size as my charge piping

carlos8

I have something similar Ls VTEC turbo piston/rod and valve train 393whp/281tq. I went with the Alpha 66mm 2.6" with 2.5 charge pipe and manifold match, works great!!

OneBadTurboCRV

At a minimum, yes. For your moderate horsepower you can get away with stock though. No need to upgrade.

turbomaniac

this has to do if you have low power. With 400 HP, there is no matter even if you have +20-30% throttle body dia.

There will be always the restriction of throttle body bolts, so you cant go more than +30-50% at throttle size......

i agree for the rule " at least the same size as your charge piping "

m4xwellmurd3r

U can ruin the engines driveablility by going ti big on ANY car. I dont care if its a 200hp low boost tiny turbo setup or a 600hp firebreather.

Your throttle body should be sized to reach atmospheric pressure at around 80% throttle opening. Meaning hy the time you hit 80% the engine is flowing as much as it can. The last 20% will make zero change in power.

People misperceive decreased throttle control and massive increase in response as a gain in power. While some gains may have been made, the engine isnt making any power power past a certian throttle opening (lets say, 50%) at 50% the engine is breathing at wot.

I do agree that the throttle body should be sized to closely match the charge pipe, but at the same time, the throttle body size should be based off the power you expect to make. A 60mm tb is fine for most builds till you start going above 500+hp
I think instead of sizing your tb based off charge pipe sizing, you should size the charge pipe based off the tb and turbo outlet.

blackeg

im sure its not helping me, but im using a stock 60mm tb on a victor x and feel that my motor makes good power for the turbo and boost pressure. perhaps it helps keep charge velocity up so it can fill that bigger plenum but im not really sure..see sig for dynojet numbers

slammed101

Wilson 90mm 👍