Ok I am goin with a JG Edlebrock Victor X Manifold and I was wondering on the Throttle Body what size I should go with? I have a B18c GSR motor. I have looked at 62mm 65mm 68mm and 70mm. What would be a good size for 2.5" turbo piping? and is 2.5" turbo piping big enough for a turbo that is hoping to push 450whp with a fully built motor? Thanks

 

2.5 is plenty big enough for 450whp. and when i was making that much i was running a stock b20 tb. but with my new build i am running 3'' piping and a 74mm tb which is right at 3'' also.

 

the TB should be at least as big as the plenum inlet. Preferably larger.

I'd recommend a 70mm TB.

 

ok 2.5" on turbo piping and 70mm TB? thanks alot

does anyone know if STR TB's are any good?

 

There are plenty of people that have made awesome power with stock Throttle bodies. I would invest the 300 bucks into something else

 

2.5in piping with a 72mm t/body

 

You could also pick up a mustang t/b from a junk yard. they are 70 mm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95GSRTT &raquo;</TD></TR><TR><TD CLASS="quote">There are plenty of people that have made awesome power with stock Throttle bodies. I would invest the 300 bucks into something else</TD></TR></TABLE>

if you have a larger plenum inlet on the I/M then the outlet on the TB...then it kills air velocity.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by _gurusan_ &raquo;</TD></TR><TR><TD CLASS="quote">if you have a larger plenum inlet on the I/M then the outlet on the TB...then it kills air velocity.</TD></TR></TABLE>

So??!! Like opening up into the plenum doesn't "kill velocity"! Go read what you wrote again, and then the next time you want to write something like that, don't.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by _gurusan_ &raquo;</TD></TR><TR><TD CLASS="quote">the TB should be at least as big as the plenum inlet. Preferably larger. </TD></TR></TABLE>

You want the plenum ID to be bigger than the throttle body outlet. There is no reason to run a throttle body with a larger opening than the plenum. It will probably make less hp. You always want to "step" up in size not down. You need to port match the plenum to the throttle body if you do run that big of throttle body.

 

aint JG Edlebrock Victor X's a 65mm outlet? So should I go with 62mm or 65mm TB? Cause I thought 70mm was way to big for it, but i have people tellin me its not. if I go with the 65mm i am goin with JG's. but stock or what? Thanks

 

What I meant to say is that you want ot keep it nice and tapered there to increase velocity.

If you had a 67mm tb and a 65mm plenum inlet the taper would increase air velocity.

If you have the plenum inlet larger then you are creating a pressure drop right after the TB.

 

65mm tb? then??

 

i made 492 on a stock f22 TB

 

Personally, I would run at a 67 or 68mm tb.

But apparently everything things you shouldn't listen to me.

 

2.5 is more than enough. personally im running 3" the whole way with a 75mm inlet mustang tb.

 

How does that mustang TB work out for you?

What kinds of issues did you have to work out to get it to fit?

 

i have a 70mm BBK TB on my BBK IM which has a 70mm plenum and i love it it is really good up in the higher rpm, in your case because the JG EDELBROCK IM has a 65mm plenum i wouldnt recommend a TB bigger than 65mm,
i personally would go for a 65mm TB on the IM u have.
ALSO for the choice of TB STR is good but my personal preferation is a BBK or JG TB because it comes with a pipe like the stock TB so u can connect the fuel vapour line but with a STR u dont have that which means u have to leave it disconnected and this leaves a fuel smell in the engine bay and the inside of the car.

 

damn im only running 2.25 piping with a stock gsr tb

 

I have heard there is no reason to run a TB larger that your IC pipe's. If you think about it isn't the throttle body like an extension of your IC pipe's? If you open up the dia (say 2.5 to 3") for the length of the throttle body (2" or so) is it really going to help? More important is the IM and runner size. Maybe someone who really knows or has dyno plots can chime in?

 

I will also be using stock TB to around 620 whp. Check out Boosted-Hybrid's dyno page and see what guys are using for different power levels. I think the $300 can definitely be put to better things especially at 450 whp.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by g2turbo &raquo;</TD></TR><TR><TD CLASS="quote"> I think the $300 can definitely be put to better things especially at 450 whp.</TD></TR></TABLE>

I would put the $300 elsewhere also for example IM or tuning.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95GSRTT &raquo;</TD></TR><TR><TD CLASS="quote">There are plenty of people that have made awesome power with stock Throttle bodies. I would invest the 300 bucks into something else</TD></TR></TABLE>

I agree.

 

so for 450whp pump gas goal I shouldnt go with a TB? I mean I want to pull as much hp out of my engine as possible, to start off I would like to get it to around 450whp on pump gas. So if I dont need a TB I agree I should put it elsewhere, and i would love to save 300 dollars on this build and still get 450 on pump. So should I just stay with my GSR TB? Thanks

 

Keep it stock.