What is the ideal size throttle to use on an aftermarket inlet?

I have heard BMW do a 65mm, Volvo do a 70mm but don't know which diameter and from what vehicle is best to use on a YB

Any info cheers

 

Why do you need to when a standard 2wd cossie flows enough for 700bhp?

 

my 4x4 inlet and standard throttle bodie has done 525bhp @ 2.2bar... looking to fit hart or a swedish now

 

Why did Ford revise the size of the original ST Escos TB if the 4x4 item flows so well?

 

If no one tried to excel themselves then we wouldnt be any where in life

 

no idea mate, but they were 200bhp so i dont think there was any restriction in the slightest so why they changed it im not sure

 

Delta intergrale is a direct replacement apart from the mounting holes,same tps.65mm butterfly instead of standard 57mm.only benefit is better response I was told.

 

Most likely they already had another car using the same tb, or it was due to the fitment of a different iscv.
Bigger doesn't always equate better, ideally as small as possible is best keeping the air speed as high as possible, bigger = slower air speeds = less efficient mixing of air and fuel, all else being equal.
tabetha

 

So anything bigger than a 57mm throttle body on a YB up to 700bhp is a complete waste of money?

So why do they make intercoolers with larger pipe work and the RS500 come with larger system from turbo through to the inlet?

If so i shall stick with the standard item

 

Bump this if anyone has any more feedback regarding larger throttles

I've just hidden two throttle body's at the scrapyard pending if i need one - ones of a Ford 4.0 V6 explorer and tother is a BMW E32 735I both around 65-70mm - nether run an ISCV though but do you need one when live mapped??

 

I'd bet at 700hp there would be gains to be had above 57mm

 

so what about 4-500bhp martin?

 

Martin, very very minimal

Ran there is no issue with standard size and most on this forum will not need larger especially brammer as he's only looking for 500s

 

saying a bigger body wont make a difference is the same as saying pushing the throttle pedal down more wont make the car go any faster. Of course supporting mods help also

 

Chaffee Have you actually tried them on same spec engines engines? We have, and eyre within a few bhp. theres no restriction, and engines made 690bhp

at the power levels the OP is looking for and much higher there is no restriction by the standard throttle body

But saying that I'm sure somewhere on a rolling road it will make a difference of 10bhp at 450bhp
If

 

not on a 16v pinto, but on other 16v engines, no power figures to confirm though. Just the way i see it is like this...
You open the throttle more to go faster, so the bigger the throttle body the more power you will get (upto a point that the other mods are then holding it back)

 

Well if engines have been tested thats good enough for me, the money can be better spent elsewhere

 

My engine did 540bhp on standard 2wd throttle body mate

The limiting factor is how much fuel you can get in, not the size of the throttle body

 

Fuel isn't an issue Gav.

 

Neither is the air Martin it gets through there perfectly

Chaffe what you have just said is crazy, maybe on a n/a engine as you want as much air in the as possible but a turbo engine is all forced through so you don't need such big throttle bodies and big inlets your just going to get less throttle response

 

Brammer would you like to see some dyno sheets? What power are you looking for?

Iirc a gt3076? If so escos gaz engine made 545 on a std throttle body with this turbo

 

I'm sure the one I did for Franco made about that on a std throttle.

 

rs500 got a bigger throttle than a normal cosworth

mine is 76mm im sure same as cooler outlet

 

What size is the outlet of your turbocharger ?

 

Dos have an effect on N/A engines as said went from 58 to 64 on a v6 mainly the pick up was better was a tad more crisp to max revs.

 

Exactly !

Surely its about the air speed and keeping things equal.

For those that that haven't seen it have a look at MK's Fiesta thread and the photos and write up of the current Fiesta WRC, I'll go with the fact that if Msport have tested everything and come to the conclusion that a small tb works perfectly then there is no need for a larger one than the Yb comes with.

IIRC they use something around the same size as a stock Cosworth one.

Very interesting pictures and info for those that haven't seen it.

 

Mine made 549 on standard 2WD TB but have not tried it with a bigger one to see if there are any gains to be had.

I also like the fact you get the easy ISCV placement with one too. Remote is doable but more of a pain.

Stu

 

It is 3076 Jim so post some up mate

Standard size outlet, as far as i'm aware it's the same as a T3

So to keeping the standard 57mm throttle the inlet and outlet on my intercooler are fine as theirs no stepping up nor down in the pipe work they are all equal from the turbo all the way through to the throttle body.

Which brings me to the question why do intercooler manufacturers e.g Pro Alloy put larger outlets on their coolers or is their absolutely no real point?

Or is the point when you have the larger cooler pipes then you step up the size all the way through including the throttle body e.g ST Escos - is this the main reason why the RS500 has a larger throttle set up as it's larger from the compressor housing so keeping it constant continues right through to the throttle?

 

i have a st throttle body will this be suitable for my t4 at approx 530bhp

it's on a hart inlet

 

so why does a turbo car go slower at half throttle then? surley its all getting forced through as you say so it shouldnt go slower with less throttle? fact is doesnt matter if its NA or turbo its still air, and it will still go faster the less restricted it is. Although i would say the most important factor here is prehaps not the throttle body, the set up will only be as effecient as its smallest restriction.
Also why did they bother fitting individual throttle bodies on the pulsar gti-r if it makes no odds?

 

Actually, if you've driven, owned or tuned many turbo cars. Often the latter throttle openings do make virtually no difference to power. Again depending on how oversized the TB actually is.

 

Do you get full boost at half throttle then chaffe?

Independent throttle bodies, or barrels which the gti r actually is is down to the response side,

Have you seen the size of the inlet to the plenum of a gti r ?

Also, how will air be restricted when there is no restriction? The tb is not restrictive so isn't going to make a difference?

 

I have that, and yes at low rpm the throttle makes no odds, higher rpms are different though.
Iff all pipes are 3" and you have a 2" throttle body then where is the restriction? This is what i mean by supporting mods, of course it will make no odds with 2" pipes and a 2" body. And yes, ive seen a pulsar engine, i built this one;