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!

[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?

[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.

[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

[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.

[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.

[itiejim]

Indeed it is.

[itiejim]

Thought I'd update this thread with a result (just to prove that people's advice is listened to)! I bought the Garrett intercooler core recommended and went and had a nice chat with my friendly local aluminium fabricating genius - Dave Cale in Malvern. I looked at the advice from Garrett regarding end tank design and, incorporating that into the space constraints, Dave came up with what you see pictured below (just the final welds and inlet / outlets to go on).

Thanks for all the advice folks, hopefully the IC will work well, but if it doesn't I have a stunning bit of aluminium fabrication to gaze at anyway

[itiejim]

The end pipes are now on (and have beads)!

[itiejim]

Thanks. He makes wooden bucks to shape the aluminium over. I think I've got another photo with a picture of them in the background. He's an ex-Morgan body man who I came across a year or so ago and the quality of his work is outstanding. He's currently building bodies for a Bugatti Atlantique and a Cobra, both from scratch. When I saw the artistry I just had to have a piece of his work on my humble, home brew Spitfire. So glad I did.

[itiejim]

Picture with wooden bucks in the background.

[itiejim]

Thanks for the input, I'll take your advice on the ring gaps. Should I keep the second ring gap as per OE spec?

I'm building it as a VVC with Westwood liners and the Turbo Technics pistons and rods. I'll probably get the crank nitride and the lot balanced.

Are you running 300+ bhp through a totally standard bottom end?

[itiejim]

High praise indeed, thanks

I don't really understand what you mean by the racetrack profile, but if we're talking about nth degrees of improvement I suspect I can live with it as it is.

Having said that, if you can explain how it might be improved I'll certainly feedback to Dave, the fabricator, for inclusion in future projects. Thanks to all for the input on this project.

[itiejim]

That's very interesting, thank you. I will have 52mm piping running from the air box to the SC and the same size from the SC outlet to the IC, and then on to the inlet manifold. At that point there is a step up to 58mm (from memory) where the throttle body was originally located and the charge moves into the original VVC inlet manifold (albeit modified to to allow the inlet to face in the opposite direction).
I'm using a home made airbox built into the bulkhead which should hopefully utilise a high pressure area at the base of the windscreen (with the help of a bonnet scoop) to get a straight inlet run into the SC.
Listening to your experience, I'll try to ensure that there aren't any protrusions into the airflow.

[itiejim]

That is the case, it's the same size and has a nice straight run without obstruction. Thanks, James.