Intercooler Tech 101

[Skyrine-Dave]

Ok I have a few questions and thoughts that have been bugging me.

if you have something to contribute please do.

Firstly... Why is it better to have a thicker intercooler core?

my current intercooler is 600x270x55 core.

I think this is going to be too restrictive if i am trying to make 450+Hp @ wheels.

I was then thinking with a 76mm thick core air flow would be pretty good as you have 3" inlet/outlets... 2.5" inlet piping and 3" outlet piping. Therefore the intercooler isnt really a restriction in terms of size.

How does a thicker core help with intercooler? and would it really matter for a street driven car with the occasional drag track work out?

The "hybrid" intercoolers @ 600x300x76. Someone selling these has said they are rated at supporting 500-600hp. But I have checked places such as ARE who rate a cooler that size at supporting ~250-270rwkw (well below 500-600hp).

So who is trying to sell me on their product? the supplier with a mass of cheap intercoolers... or the company wanting me to spend $$ on a larger cooler?

Reason why i am tryin to find out is my current intercooler is only 55mm thick and has a taken a nice hit in the front from a concrete block. It still works fine, but i want to be using the best, and dont want to be inhibited by a poor intercooler, when i put the RB30DET, GT35 + 20psi boost through it when i aim for 450-500hp.

if that made any sense, post ya thoughts :headspin:

All

[paulr33]

not sure if the helps but the stock r33 gtr intercooler is good for 300rwkw os find out what core/size it is and maybe use that a reference point, theres heaps of people who would know the answers to this just not sure if they will reply or not

[Fitzpatrick Speed Works]

quite literally bigger is better because there is more metal.... More alloy means more to heat up thus the cooler is more efficient as it has a greater surface area and mass!! Simple in your house the tap furthest away from the hot water usually takes the longest to get hot 1 becuase it has to push all the cold water out but 2 because the pipes take longer to heat cuase they are longer!!!

Internall design effects flow rates significantly perhaps the fins are smaller inside the tubing on the hybrid units which means more flow but less mass!!!!

[Skyrine-Dave]

nice explanation Daniel!

I think a GTR cooler is ~600x300x76 in dimensions. But for all intents and purposes we'll say it is.

How can you say a cooler is inefficient at xxxxKw's ? what are the tell-tale signs?

I've got a few options, which may also temp other people:

1) Get a new core for my busted cooler

2) Get a new 'Hybrid' 600x300x76 $425 delivered to my door

3) Get a new 'Hybrid' 600x300x100 :wassup: $600 delivered to my door

I just want to make the right decisions for my car, my power target AND for my wallet.

[paulr33]

also remember larger means more lag as the system has to be pressurised before its effective so if you have a monster truck intercooler expect lots of lag while the intercooler goes from 0 pressure to full pressure and then directs flow into the plenum. it wont affect overall top end power just add more lag to the system

[Skyrine-Dave]

yeah thats true. But i dont think a 3L with a GT35 with a small exh hsg is going to take long to come on boost. I wouldnt mind a little bit of lag to assist with getting some traction to get moving.

But i spoze the trade off between efficient intercooling at high power levels is to have a larger sized cooler and associated with that is lag... hmmm

[Fitzpatrick Speed Works]

I my car i went from a standard core 600x300x50 to a trust drag spl core 640x340x128mm and i didnt notice any difference in lag, that is probably because my old core was too restrictive and the new does take a while to pressurise but the fact it flows is more benificial!!! I would go the hundred its not much more money its not goin to effect lag significantly over 76mm but its alot more metal which means more heatsoak potential and cooler inlet temps!!! Cheers, Daniel.

[wolverine]

neat analogy with the hot water pipe, imagine if the pipe was effectively empty and on the other side of the house?? how long from when the tap is opened till water reaches the other end??

bigger is definitely not always better, response is worth plenty when it comes making quick cars.

[Bl4cK32]

dave,

Im going the same route as you (rb31det with gt35/40r and 20psi +)....

Ive chosen the HKS drag kit (type R) (600x300x110?) I like the end tank design as well...dont be too worried with its size on the rb30

[TTT]

I don't get why people keep saying that the cooler has to be pressurised from 0 pressure to full pressure..

when the car is idleing, air is still in the pipes and cooler.. it's not like it is empty then when you step on the throttle nothing happens while air is filled up in the pipes and cooler and THEN you start to move..

but one other thing..

if you buy a 100mm thick cooler and I presume Bar and Plate, what radiator are you using and will it get any decent air flow to it to cool it?

also, one Intercooler company is always going to put another one down.

[Skyrine-Dave]

I have a very large PWR aluminium radiotor that is 2-3" thich and there are 2 thermo fans behind that. On my rb20 i would start to panic if water temps went above 83deg C

[Spagman]

2) Get a new 'Hybrid' 600x300x76 $425 delivered to my door

Where do you buy these from? Any sites?

edit: stupid quotes, or stupid me :Oops:

[Skyrine-Dave]

There are group buys here, but i saw that price on www.calaisturbo.com.au in the for sale forums.

[Sydneykid]

Hi guys, here is an example of 4 intercooler setups and pipework we have actually used;

1. R33 GTST Standard Intercooler and standard R32 GTST pipework

150 rwkw = 27 lbs of air per min @ 13 litres of i/c & pipework

2. Supra Intercooler and matching 63mm pipework

180 rwkw = 30 lbs of air per min @ 15 litres of i/c & pipework

3. Standard R33 GTR intercooler and 63/75mm pipework

250 rwkw = 40 lbs of air per min @ 21 litres of i/c & pipework

4. Greddy 600 X 300 X 115 and 80 mm pipework

400 rwkw = 60 lbs of air per min @ 28 litres of i/c & pipework

If you look at the numbers you can see that the rate of air flow and the volume of I/C and pipework have a fixed relationship (27 = 13 , 30 = 15 , 40 = 21 , 60 = 28). This is not an accident, I designed it that way. The reason is I wanted to keep the throttle response as close what it was when the car had 150 rwkw, because I though that was very nice response.

The theory I followed was, the more power the engine produces the more air it needs. Thus if I keep the increase in the volume of air inside the inlet system in the same proportion as the power increase, then the throttle response should stay the same. This is based on the engine using the air in the same time frame.

So when people say they fitted a FMIC and have not noticed any less throttle response, my response would be, that is what I would expect. As long as they went from 150 rwkw to 180 rwkw. On the other hand, if there was no power increase then it would be simply physically impossible for there to be no decrease in throttle response.

The problem of poor throttle response arrises when you have a 220 rwkw engine with a 28 litre inlet system. This is something I see way to often.

Hope that adds to this interesting thread.