Hi

What are the physical differences between an STI4 intercooler and a STI5 IC. Are there any obvious markings, part no's or dimensions to differentiate the two.

Also what is the performance increase between the two if any.

The reason I ask, is because I will be looking for an STI5 IC( seem to be the prefered option after STI8 IC ) to go onto my 97UK turbo in the near future( modest power increase with other mods 290 BHP), and I need to know what I am looking for, to make sure I buy the right one.

Andy

 

im sure the intercoolers are the same bar where the dump valve fits on

 

There was a thread on 22B.com about this recently, the outside is the same but internally they are different. As for performance, the V4 flows better but is not as good at cooling. And conversely the V5 flows worse but cools better.

 

So I take it that due to the tuners and modders prefer STI5 IC, then thats the one to go for. Still leaves me with the problem of recognising which is which if they look identical from the outside.

 

They don't look identical. The version 3/4 will have a 90 deg leg coming off on the passenger side front of the IC for the dump valve. The version 5/6 dump valve just bolts straight to the IC in the same place. You will either need the V5/6 dump valve or an adaptor pipe to suit your current dump valve.

Tony.

P.S personally i wouldn't really bother with either for the small gains you will get.

 

Sti V5/6/P1 TMIC looks like this...



To standard dump valve (shown in pic above) won't clear the inlet manifold on your MY97. You need an adaptor like in the next picture, these are available from Hayward & Scott.



Then you will need to modify the intercooler/gasket so the dump valve ports meet. Taking huge care not to leave any swarf inside the intercooler.





Then you will most likely have to modify the N/S mounting bracket to mount it. I had to file the holes where the bracket bolts to the inlet manifold out a little to i could have the bracket sitting slightly further back.



Looks cool once fitted but that's about all..



I'd seriosuly consider just straight swapping an STi V4 one if i were you. That intercooler cost me the best part of £200 (more inc. Samcos) once fitted. For the amount of fecking around i did i'd rather have gone STi 7/8.

 

pic of STi 4 nicked from For Sale.

 

Thanks for the reply Carl

Andy