Silvia Club of NSW

Dear all,

Just hunting around for a intercooler. Was wondering if there was any big differences between the trust, hybird and HKS intercooler?

your subject line says interooler.

do a search on this,interCoolers are one of the most commonly discussed items on here,after the GTRS and T518Z.

my girlfriend's car has a hybrid core on it,which seems to work fairly well.
rule of thumb: get the maximum frontal area you can,with at least a 70mm core thickness. keep the piping as short as possible,and as small a diameter as your peak flow requirement allows.


Justin...

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STI - Made in Texas,not Japan.

The search button is your friend. Use it. Trawl through the pages of opinions and information, then ask if you still have any questions.

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meh

anyone using the trust m-spec ? i think CRD is selling them off for 600 at the moment.

What interests me is knowing what size piping to use? Mines 2" turbo->IC and 2.5" out to the TB. It looks tiny but it works? I would have assumed using a larger turbo->IC pipe would be more beneficial as the air is extremely hot and thus less dense and occupies more volume for the same mass flow.

personally i think it should start off with the size of the compressors outlet say 2" and gradually increase in size to the diameter of the TB, say 2.5" - the more gradual the increase the better.

the idea with the intake is to maintain the pressure, so a larger pipe just means more volume to fill before the same pressure is reached in the inlet/plenum (flow capability isnt dictated by achieving the least amount of pressure in the pipes like it is in an exhaust). a smaller pipe will give higher velocities which is a benefit for cylinder filling, and flow capability into the plenum should be largely dictated by the TB diameter rather then the piping. TB should have a surface area the same or slightly larger then the total surface area of the 4 runners.

well thats my flow of thought

I working on them same pricipal 2" out of turbo 2" short hose 2" into IC, 3" out of IC, 3" short hose, 3" into TB.

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I didn’t break it, I just modified the operational status...
There are 10 types of people in this world, those that understand binary, and those that don't.

Hmm but remember only 1 cylinder at a time is swallowing air at any given moment, so crude theory would say the TB only has to be as big as 1 runner (obviously not in the real world tho!). The best way to measure it would be the boost pressure differential before/after the TB.

Was just thinking is when does a 2" pipe become too restrictive at say, 600cfm of flow at 1 bar of pressure? Just like a straw, you can only empty that glass of coke so fast and you can do it a lot faster with 2 straws!

Guess it would depend on the length.. You would want the smallest diameter possible provided it doesn't restrict flow. The longer the length the greater the diameter...?

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I didn’t break it, I just modified the operational status...
There are 10 types of people in this world, those that understand binary, and those that don't.

Yeah thats what I'm getting at. Actually come to think of it, its easy to do with car audio power cabling -

You juggle around how many amps (flow), the voltage drop (boost pressure loss) vs cable gauge (pipe diameter) & cable length & resistance (pipe length).


There is a mathematical equation to do that. Anyone know what the same equation is for piping?

I get so lazy when I type that i dont fix up the typos.

ah yes good point, that complicates things alot more - but obviously for some reason that sort of size isnt sufficient, but interesting that the s15 recieved a smaller TB. i guess then the smallest size that gives no pressure differential before/after the TB at WOT would be best ?..

the straw example cant be compared to this though, because its dealing with a non compressible fluid, and the dynamics will be alot different to a gas - which is very compressible. plus its a system working on vacuum, where as the intake is working with pressure.

given a 2" piece of pipe theres 3 ways of pressurising it. we can add a restriction on the end of the pipe (eg taper pipe down to 5mm) and so restrict flow out of its exiting orifice (much like the intake valves). we can make the end of the pipe closed, which is how the intake really works i guess, pushing air into a closed combustion chamber. and lastly, if you were to flow enough volume through the pipe that it would just naturally cause an increase in pressure in the pipe because its orifice of 2" simply cant flow enough (like how an exhaust builds up pressure) - with this method though i think you would need ALOT of flow to get the same pressurisation you would get with say method one (possibly a multiple of the comparing surface areas 5mm vs 2"). the point im trying to make is that i think the 2" pipe is going to outflow the end part of the intake by a large amount, and so increasing inlet piping size isnt going to affect the bottle neck (eg intake valve), which is the main problem/restriction.

its like having a 3" dump pipe with a 5mm pee shooter exhaust tip and a 1" dump pipe with the same exhaust tip, would back pressure be the same between them? i think so.

in terms of just a straight through pipe itself, i know the volume flow of a pipe is V = (surface area) x (gas velocity), and when you reach a certain velocity you start getting a pressure buildup above atmospheric in the pipe, thats when it *starts* to become restrictive. but i couldnt find the formula that gives the relation between pressure and velocity...