Why do some intercoolers run 76mm pipes and mate to standard size throttle body?

Is their any advantages on running bigger pipes the reducing down to throttle size with silicon hose?

Or is it better to run consistently through using matching size pipes to compressor housing and throttle body?

 

Mr Moancock always goes on about bigger is better.

On mine the outlet matches the turbo size and the inlet matches the TB size

Steve

 

less restrictions the better isnt it?

 

Better flow of air?

 

What I don't get is how can a better flow of air come from a system that is stepped up and down and has no consistency?

 

That is exactly the way I thought it should be match for match and not up and down

 

My mates got a 100mm pro alloy cooler and his has a 76mm inlet (turbo) and standard outlet using a gt3076 and it was Harvey who specced that.

 

Everybody has there own opion but im happy the way mine is lol

Steve

 

On my new cooler i opted for both std pipes due to the size of TB and turbo

 

Bit pointless really, probably jus cos it looks 'cool' and really wished they had a 3" throtle/IC pipes...i'd imagine? I can't see it having any advantage when using std throtle body.

On a side note, my pals RB30 200sx has 4" pipes/IC/Throtle body

 

jesus thats a huge cooler


looks like a air con unit you get on buildings

 

I'm changing mine so inlet side and throttle side are the same.

Steve

 

it is pretty huge. 8xImprezza IC's welded together, GT42R turbo, 3.0, low comp JE's/steel rods 5" downpipe splitting to twin 3"

 

That's some serious work. Must be pushing for well into 4 figure power ?




You are quite right. It doesnt really make much sense at all. The only reason you'd have a large IC exit, is to help smooth the flow from the end tank into the pipework. But that's more IC design than plumbing.

It also makes no sense for people to fit ridiculously large TB's either, yet most do it. I seen a local guy here with a GT4 and he...well, his "tuner" had fitted some 95mm TB to it. Seriously...a 400bhp car with a TB capable of 2000bhp. Intelligent. Open the throttle more than 30% and it's letting in all the air the engine could ever consume.

If the plumbing had loads of bends, it could make sense to make it bigger simply to account for the restrictive nature of the bends compared to a straight pipe. But in that respect, Cossies are very good. 1 bend from turbo to IC, and no bends on the IC to TB

 

I totally agree with you,
The throttle body thing does my head in, I think people forget that the throttle body is feeding the inlet ports which are tiny in comparison lol. (yes I know we have four inlets on our 4pot, but only one of these is breathing at a time, well maybe a bit more with a bit of overlap)

 

No, turbo's only rated for 850, anything over 700 I think he'd be well chuffed with, but everything's 'capable' of doing 800

 

So why such a large TB and plumbing ?

3" IC plumbing is easily capable of 800bhp. 4" IC plumbing is a bit mental unless it was riddled with bends.
A 65-70mm TB is capable of 800.

I certainly wont argue about exhaust size, because bigger is certainly better when it comes to that aspect on a turbo car.

But a 4" exhaust would have been ample for 800 ( or more )

 

4" was done to match the TB, as that's what came with the plenum, so why make it 3" when it can be 4 not going to do any harm. basically.

and a 4" exhaust, from what we know/tested isn't good enough for 800bhp, it could flow 800bhp but there will be backpressure, we want zero backpressure.


Surprised no ones asked why we didn't jus use an rs500 cooler

 

Depends on how much throttle control you need.

It's just crazy fitting a TB so huge, that when open 30-40% it is allowing in all the air the engine could ever consume.
So anything from around 40+ makes no difference.

And resolution from idle and low throttle driving, and especially the accel enrichment can be horrific. Because every 1% you open the pedal during normal driving, is like stamping on a normal sized throttle it lets that much air through.

Excessively large throttles are just plain stupid and can give no benefit whatsoever. Only downsides.

What size is the outlet on the turbocharger ?