Just wanted to see what peeps think on intercooler design and positioning.

Some of you may or may not know I turbo charged my cbr1000f powered Indy last year. I just guessed at the turbo size to use and opted for a T2 sized unit. As I can weld alloy I had a 1 off core made at pace for me to fit in the nose cone of the car. I was using the original bike radiator behind it and was concerned about over heating. Which came true so I have just fitted a polo rad which is twice the size of the original one, BUT this means I can’t fit the intercooler in front of it (unless I make the nose cone look like a tuned jap car with a huge box hanging off the front) So I have 2 options, get a charge cooler where its water rad will fit in front of the polo rad but will cost the earth and I don’t like all the other bits to go wrong with it (pump, wiring ect), or fit the intercooler else where.

Luckily for me I have managed to get hold of a small intercooler that I am going to mount in the top of the nose cone just before the front lip of the bonnet, I am currently making a nice big scoop for it which if it doesn’t work out can be used for a cold air feed to the air filter. I have done some locost wind tunnel tests (compressor and string) to see if this vent actually supplies air or not and things look promising. But in the back of my mind I still think it’s second to having a huge intercooler up front.

Also to note is that the new intercooler is a totally different shape with half the surface area getting fresh air to it compared to the front mounted one, but it’s about the same volume. The front mount was like a car rad, large and square but thin; the new one is like a shoe box and is half the size but twice as thick (dual core design). Good news is it makes the pipe run a lot smaller and will help with lag and weight, but I just wanted some advice or comments if this sounds ok or a mistake.

I have seen on here a few members have turbo cars that have their intercooler at the rear of the engine bay getting very little air flow. Is this a good idea or bad?

I believe that for a car with limited space for an intercooler a charge cooler is the answer - however the size of intercooler you need is very much dependant on the engine size, boost pressure you are running, turbo efficiency, intercooler efficiency, intercooler size and airflow temperature and velocity across the intercooler. For boost below 8psi you need relatively little cooling of the charge.

So what you are asking is - "How long is a piece of string"

The brief (not so brief!) answer is any size intercooler that is not too restrictive to the boosted air flow and sits in a flow of relatively cool air is better than no intercooler at all. I would be more concerned about high underbonnet temperatures undoing the good work of the intercooler on its way back to the engine so ensure you have good venting of the underbonnet area.

Good venting will also increase the air flow across the intercooler.

And if the charge is still too hot try a water spay on the intercooler at peak boost. Just make sure it doesn't wet the road in front of the tyres

I'm using an MR2 mk2 turbo intercooler on my 1600cc supercharged 4AGE which puts out 260BHP. Work well as my inlet temps are very low and there is minimal pressure loss across the intercooler. Have a look at the pic below because it fits very nicely infront of a polo rad. just needs about 60mm above the rad to get the inlet/outlet pipes routed.

Thinner and large frontal area is usually better as the intercooler works less efficiently towards the rear the thicker it is. You only need about 1/4 of the surface area of the intercooler to supply enough airflow.



Intercooler mounted

[Edited on 30/6/08 by bimbleuk]

Hi I am going with a sierra 4x4 intercooler,

Try to top mount above chassis rail, and make an air scoop from the front nose cone to direct air,

I know several people have done this duncan cowper a friend of muine with the busa turbo car done this and ran around 380 bhp with no probs , in the end he did run aquamist aswell though,

Hope this helps
Sean