We have all seen/read/heard claims by people (Part manufacturers in particular), that the bigger the throttle body, the better - better throttle response + hp gains. This is part of the basic bolt-ons list for the all-motor crowd and all the big-name racers use them (70mm+). Well... what about for turbo apps? As we all know, most anything that makes power on a N/A motor will make about 5x as much power w/ boost (for instance Skunk manifolds, Type-R cams, etc.), so what about a bigger throttle body? It makes sense that the bigger the better (less restriction, like that big *** 3" exhaust we run) but nobody really talks about it? What do u guys think?

 

ur manifold will still get 10psi (example) no matter if u have a 60mm or a 70mm. air is being pushed in no suck in

 

In one word, No.

 

but won't a bigger throttle body flow more?
I thought it was more about cfm than psi because two different turbos can produce 10 psi and make two different hp levels.

 

a Bigger throttle body might help at a certain point. and if you have a pea shooter for a throttle body. But the money will better be spent elsewhere.

BTW, i know people who lost power by using a bigger TB

 

yea its all about the flow...10psi might be 10psi but if youre trying to squeeze air into the motor with a 1" opening vs 3" opening which would be less restriction? also depends on turbo size to support this.

 

keep it simple.

 

boost dosen't care what thottle body you have, plus you might be able to get all that air in the manifold but the runners are going to be the same size, stick with a stock throttle body and buy something that really will help your motor.

 

i broke my TB plate on a NOS backfire, and had maxbore re do it for me, great price, took it out as far as it could go, and i made 14 more HP with no changes in settings whatso ever. i think it is 68mm, it is paper thin.

i already had an AEBS manifold, and i think the TB was holding back the manifold a bit

 

In short, YES!

The ability to allow more VOLUME of air to reach the valve will inherently enable the production of more h.p. On a 10 psi set-up, there will be no noticable difference, but on something that wants to flow a high CFM, then yes, it makes a huge difference.

One other factor that people overlook is that when you use a larger TB, you now have the ability to go up in AR size. When more volume is entering the chamber, more will be expelled and the AR can increase to aid in power production and spool time. With the ability to choose a larger AR housing, you then are enabled to adjust the TQ curve to where you like it depending on your particular vehicle set-up and gearing.

Larger TB > stock TB

 

Beautiful. Finally someone who knows what the F&*^ they are talking about!

 

To GoldenEagle's post

 

Power gains aside, the biggest thing you'll notice is the increase in response from your engine. If that means anything to you - which it should - I'd go for it unless you're getting a TB at the expense of engine management or tuning or something .

 

vince

no offense, but i didnt think so many people didnt know the answer to this question.
please dont lock this..

 

I think people are getting confused because in absolute terms, yes bigger TB makes a difference.

However, the MAJORITY of people on here do not flow cfm's to the point where the TB becomes a restriction of concern or "weak link" in the system.

 

hey u know that thing about pressure drop through the intercooler being big deal.
thats what corky bell says the same thing about the throttle body.
ne wayz maybe im goin out on a limb here but maybe the tb size should be in relation to the piping size which is to the cooler and there-fore the total turbo setup, of course right
make any sense?
-Toby

 

what is the point of bigger thottle body if you dont port match it to a intake manifold anyways. One is useless without the other...Talk to thenewspaceballs.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GoldenEagleMfg.com &raquo;</TD></TR><TR><TD CLASS="quote">In short, YES!

The ability to allow more VOLUME of air to reach the valve will inherently enable the production of more h.p. On a 10 psi set-up, there will be no noticable difference, but on something that wants to flow a high CFM, then yes, it makes a huge difference.

One other factor that people overlook is that when you use a larger TB, you now have the ability to go up in AR size. When more volume is entering the chamber, more will be expelled and the AR can increase to aid in power production and spool time. With the ability to choose a larger AR housing, you then are enabled to adjust the TQ curve to where you like it depending on your particular vehicle set-up and gearing.

Larger TB &gt; stock TB
</TD></TR></TABLE>

Thank you SIR! I couldnt have said it any better my self!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mrbsponge &raquo;</TD></TR><TR><TD CLASS="quote">i broke my TB plate on a NOS backfire, and had maxbore re do it for me, great price, took it out as far as it could go, and i made 14 more HP with no changes in settings whatso ever. i think it is 68mm, it is paper thin.

i already had an AEBS manifold, and i think the TB was holding back the manifold a bit</TD></TR></TABLE>


i thought max bore was 66MM on a stock TB ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbosi03 &raquo;</TD></TR><TR><TD CLASS="quote">I think people are getting confused because in absolute terms, yes bigger TB makes a difference.

However, the MAJORITY of people on here do not flow cfm's to the point where the TB becomes a restriction of concern or "weak link" in the system.</TD></TR></TABLE> Exactly think of it like intercooler piping. I have recently upgraded the throttle body on my S14 SR20det factory 50mm or 2 inch its tapered upgraded to a 60mm the lag is definately noticeable and there no real gain iin power on low boost. But seeing how I intend to make more then 300bhp "what 2in piping is about good for" I did upgrade it so far it has just made the car worse to drive..... It maybe better in 4th and 5th gear perhaps..

 

Your TB will start getting significantly restrictive when gas speeds exceed 300ft/s

A bit of math with your CFM and TB bore shoudl tell you what sort of gas speeds your looking at. With a bigger TB you still have 10psi in the manifold, BUT the turbo exit pressure is lower due to less pressure drop as discussed and hence operates the compressor at a lower pressure ratio which generally runs the turbo at a higher adiabatic efficiency and also serves to lower the exhaust manifold pressure hence reducing reversion in the exhaust port improving cylinder fill.

So no, 10psi isnt just 10psi with what ever throttle body.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GoldenEagleMfg.com &raquo;</TD></TR><TR><TD CLASS="quote">In short, YES!

The ability to allow more VOLUME of air to reach the valve will inherently enable the production of more h.p.
</TD></TR></TABLE>

Exactly, Like said above though port matching is key or at least making sure that the intake manifold opening is the same size or larger because if not, you're defeating the purpose.

Phil

 

Guys, just remember, everything comes back to exhaust backpressure. Sure, you can make 10psi with a 50mm t/b and with a 70mm t/b, but the restriction added with the small one makes the turbo work harder, causing an increase in exhaust backpressure. A restrictive intercooler will have more pressure drop. What does this matter if you still make 10psi at the manifold? The turbo works that much harder to make that 10psi through that restrictive intercooler. The bottom line is backpressure. A change in a/r on the turbine housing will affect backpressure, thus affecting power. A sharp 90 degree bend in your intercooling piping will have more restriction than 2 gradual 45 degree bends, thus causing an increase in backpressure. If you go to Denver, at 5000ft, you can will probably still make 10psi, but the turbo has to work alot harder to achieve that....gues what...backpressure...

 

Well put Tony

 

of course it makes a difference. If it didn't then I guess it wouldn't make a difference if I raced at half throttle or full throttle as long as the turbo makes full boost!

should have my new intake manifold and 65mm throttle body soon.
gonna be a few more months before I change the turbo and exhaust