I was wondering what the high hp vehicles are running in terms of throttle body & charge piping size. I am upgrading again and wanted to see what is common.

Using 2.5" charge pipe and a 62mm throttle body with a bored stock intake manifold I made around 550whp at 22psi. I'm pretty sure the charge piping will be sufficient, but would it be worth increasing the throttle body size? As it goes right now the throttle body is still larger than the intake pipe. Will going to a 70 or 74mm do that much (especially if the charge pipe remains at 2.5")?

 

bump bc im curious too

 

I would go up to 68 and that’s it
You will prolly see maybe 15 HP gains at certain parts of the power band with a little bit of tuning
No way to really be sure till you try it
I say go for it

 

It would be pritty pointless to run a 2.5" pipe with a 74mm tb sence all your feeding air for is about 68mm throught that 2.5" i/c pipe.

p.s people have ran 9's with 2.25" i/c pipes..

 

typically, you should gradually blend the piping size so that off the turbo you have the same diameter pipe as the outlet, then fade it to the inlet of the IC, then fade to the size of the throttle boddy. I have a large turbo so the turbo outlet is 2.5", so I have a 2.5" that fades to 2.75 for the intercooler, then it maintains 2.75 to the TB. stock GSR TB by the way. though people have impressed me with ET's and weird pipe diameters, it makes no sense in an airflow respect to have the final charge pipe any other diameter than the TB.

 

3 inch, 75mm throttle body here....




4 inch 105mm throttle body here

 

this 4 inch charge pipe is just freaking huge !!

Personnaly for your goal I would go with the 2.5 inch piping and try to get a TB with almost the same diameter or so.

 

The bigger pipes you go to then the longer it will take to pressurize, the only advantages would be for the larger turbos pushing stupid pressures.
I'd go with the 2.5" piping

 

iam going with 2.5" and i will be making around 550 whp so you will be fine with that size pipe

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C1CYA &raquo;</TD></TR><TR><TD CLASS="quote">iam going with 2.5" and i will be making around 550 whp so you will be fine with that size pipe </TD></TR></TABLE>

I already was making 550whp...so obviously 2.5" pipe can easily make that power. All I was really looking for with this topic was whether or not I should be running a larger throttle body.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by agileauto.com &raquo;</TD></TR><TR><TD CLASS="quote">typically, you should gradually blend the piping size so that off the turbo you have the same diameter pipe as the outlet, then fade it to the inlet of the IC, then fade to the size of the throttle boddy. I have a large turbo so the turbo outlet is 2.5", so I have a 2.5" that fades to 2.75 for the intercooler, then it maintains 2.75 to the TB. stock GSR TB by the way. though people have impressed me with ET's and weird pipe diameters, it makes no sense in an airflow respect to have the final charge pipe any other diameter than the TB.</TD></TR></TABLE>

My outlet is also 2.5", so I do run 2.5" charge piping into my IC and then out to the TB. The IC was custom made to have 2.5" ends. Would it be worthwhile changing the piping after the IC to a larger size? Would this increase not also increase lag?

 

70mm at the best dude I wouldn't change a thing 2.5" is sufficient for 650-700whp.
I have 3" i/c pipes on my car that I upgraded from 2.5" and I didn't really see or feel that big of a diff..

 

My friend pushed 657 WHP with 2.25 inch charge pipes. 2.5 is more than sufficient and as for that 4 inch charge pipes, that's rediculously HUGE!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dturbocivic &raquo;</TD></TR><TR><TD CLASS="quote">3 inch, 75mm throttle body here....



</TD></TR></TABLE>

just got the car back from the dyno.. running a stock 1st gen b16 bottom end the car made 314 hp, 11.8~11.9 a/f ratio's, 10-11psi, 26 degrees of timing on 93 octane.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dturbocivic &raquo;</TD></TR><TR><TD CLASS="quote">

just got the car back from the dyno.. running a stock 1st gen b16 bottom end the car made 314 hp, 11.8~11.9 a/f ratio's, 10-11psi, 26 degrees of timing on 93 octane. </TD></TR></TABLE>

26 degrees?? Jeezus ****

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by newgsr &raquo;</TD></TR><TR><TD CLASS="quote">

26 degrees?? Jeezus ****</TD></TR></TABLE>

thats what i thought. i dunno. im gonna put my egt guage on it sometime and see how hot she is getting up top.

 

I was running a 2.5in outlet on om T-series turbo to 2.5 piping to a 2.75 IC inlet and outlet. 2.5 piping all the way through to a 70mm Throttle body with a bored out intake manifold.

Oh yeah the piping had a small dent coming off the compressor side of the turbo, all the runs were made liked that..and it loved it!

641whp and 439trq on one run at 8600rpm and
600whp and 500trq at 6000rpm on another run when the pipe blew off!!

 

What would be the purpose of getting a TB that is larger than the charge piping (because in my head, there is no purpose)? The intake manifold volume is a different story (people often increase the overall volume, etc.)

 

a larger tb, in a way, would make the plenum have more volume.