Air to water intercoolers - educate me

[itiejim]

I'm currently adapting a Turbo Technics TT260 kit, originally designed for the K-series engines Elise / Exige, to fit the same engine but fitted in my '67 Spitfire. This uses their own design centrifugal supercharger.

The TT kit uses an air to water intercooler, having read up on this I think that retaining this, rather than an air to air system would be best for my needs. Anyway, the TT intercooler is clearly made to fit the very tight Elise engine bay and I have rather more space to play with. The original IC seems very small, just 10cm x 8cm x 20cm so I have been looking at alternatives which would suit my packaging requirements and may perform better. An example I have found has a core which is about 20 x 40 x 10, this would fit nicely and (to my mind) cool better and suffer less from heat soak. So, within the proposed range is bigger better? Also, are the generic eBay type units reasonable in performance or is there a whole well evolved science at work here that means I'd be better off with the standard small TT IC rather than a far bigger generic one?
Apologies for the long post, but I'm new to forced induction and like to take decisions based on a basic level of understanding!

[stevieturbo]

If space is limited, then buy the best cores you can...ie Garrett.

Buying a cheap core would be a backwards step unless perhaps it was far far bigger than you had now....and even then without testing it could still be a gamble.

Big core, big ( huge ) front water core and lots of water flow.

[itiejim]

Thanks for the feedback, space is not an issue. I could buy a generic core with well over four times the capacity. Does that sound like a good trade off?

[Ive]

In a front engined car with space to spare I would convert to air to air.
Have a Rotrex SC Rover S1 Elise myself

[itiejim]

I really want to eliminate lag and pressure loss as far as possible. Using an air to air cooler will mean much longer piping to get it right to the front of the car which I am concerned will affect driveability.

[eliot]

itiejim said:

I really want to eliminate lag and pressure loss as far as possible. Using an air to air cooler will mean much longer piping to get it right to the front of the car which I am concerned will affect driveability.

Lag would be minimal, you are talking of hundreds of cubic feet a minute - how long do you think it will take to fill the pipework?

You might see 1 psi loss, but how do you know you are not loosing 2 psi across the current setup.

I spent lots of time on air to water and ultimately replaced it with air to air and have never touched it since.

[chuntington101]

Air to air intercoolers are simpler easier and lighter whilst also being more efficient.

Air to water setups come into their own when you can't get enough cold air flow to the intercooler(s) (ie mid engined), or you are restricted by packaging (top mounted PD supercharger).

[227bhp]

If you look back a few pages you'll find this was done in a couple of threads about two months ago, lots of info there.

[jontysafe]

Go air/air the difference in pipe lengths will not effect either spool or power to a noticeable degree. Keep your pipe diameter small as well.

I've just had a custom made air/air intercooler done with a Garrett core.

What psi are you running and what power targets?
Where are you based?

[stevieturbo]

If you're going to the trouble of custom work....just use a Garrett core and make it all has big/sensible as you can.

I too would not want long IC pipe runs for a front mounted air to air unit on such a car. It just wouldnt make any sense.

Or other option is if you could locate an air to air core somewhere at the rear ? Garrett's air-air cores work amazingly well.
Recently fitted one to a car and the difference it made vs the old unit is truly staggering.

[jontysafe]

stevieturbo said:

If you're going to the trouble of custom work....just use a Garrett core and make it all has big/sensible as you can.

I too would not want long IC pipe runs for a front mounted air to air unit on such a car. It just wouldnt make any sense.

Or other option is if you could locate an air to air core somewhere at the rear ? Garrett's air-air cores work amazingly well.
Recently fitted one to a car and the difference it made vs the old unit is truly staggering.

Why would it be a long pipe run? It's a front engined spitfire

[itiejim]

Thanks for all the feedback, I'm near Malvern, Worcestershire.

I am looking to make 230 bhp, up from around 160 now. Turbo technical claim that the system produces 0.7 bar, however, with no BOV I am unable to recoup any pressure lost between the compressor and the engine. The installation is indeed in the front of a Spitfire, so pipe runs would not be excessive.

It sounds like I should reassess using an air to air system and ensure I use a quality core then. The current pipe diameter is 2", which I had intended to retain.

Edited by itiejim on Wednesday 7th September 09:10

[stevieturbo]

jontysafe said:

Why would it be a long pipe run? It's a front engined spitfire

Never even noticed that, just seen the Lotus reference and assumed mid engine.

Yep, just fit an air-air. Keep it simple.

[eliot]

itiejim said:

, with no BOV I am unable to recoup any pressure lost between the compressor and the engine.

What do you mean by this?
BOV is to release pressure when you snap the throttle shut and the compressor is trying compress air against a closed throttle.

[jontysafe]

2" tubing will be fine, you could even go smaller at 0.7bar and 260bhp.

This is the core I would look at:

Garrett part number 703518-6015

I bought mine here:
http://www.turbosbytm.com/intercooler-core-air-air...

And had it made up here: http://www.tylahmotorsport.co.uk/mobile but you could go far more local.

[itiejim]

eliot said:

What do you mean by this?
BOV is to release pressure when you snap the throttle shut and the compressor is trying compress air against a closed throttle.

My mistake, I'm an FI newbie, I think I meant a wastegate? Effectively, there is no bleed for excess pressure created after the compressor, therefore I wish to lose as little of what is generated as possible.

[itiejim]

jontysafe said:

2" tubing will be fine, you could even go smaller at 0.7bar and 260bhp.

This is the core I would look at:

Garrett part number 703518-6015

I bought mine here:
http://www.turbosbytm.com/intercooler-core-air-air...

And had it made up here: http://www.tylahmotorsport.co.uk/mobile but you could go far more local.

That's very helpful, thank you. I see that Garrett produce their own end tanks as well. Is it advisable to use these to ensure effective flow or will any good aluminium fabricator be able to get the best out of a good quality core?
It'd be useful if you could PM me the sort of price I should expect to pay for the fabrication so that I have something to compare things to if I speak to a local company.

[jontysafe]

To be honest I wouldn't use Garrett's end tanks. I don't like the shapes.

You want as smooth as possible transitions. And top feed if at all possible.

Will pm you

[stevieturbo]

Any decent fabricator would be able to design end tanks specific for your car, rather than generic ones.

[itiejim]

Thanks both, top feed will be fine in my application, I have a local fabricator who I can have a chat with about this.