Which cam profiles

[wez]

Hey Guys,

Was just wondering what the recommended CAM profiles are for inlet and exhaust for stock turbos or small single.

I know the J-Spec and UK spec are different as stock, which are better and what sort of improvments could be expected?

What make should I go for, HKS, Crower or JUN etc.


Regards

Wez

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[alex h]

Roughly 256in and 264ex for a j-spec. The cams are different durations stock so this roughly keeps the balance the same. Iy you are just going to drop them in without any other work then I would use HKS as they have alower lift than JUN. But if you are doing the job properly with new springs and shims etc then I would go for JUN cams as they have more lift.

HTH

[wez]

Thanks for the info Alex http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/smile.gif

What are the power/torque gains from upgrading the CAMS, I have an AEM as well so could I possibly benefit more from say 264/264.

What is the benefit of having different inlet and exhaust profiles?

Wez

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[Chris Wilson]

The stock, very small, exhaust housing sizes dictate to a large extent what cams you can get away with. You can add lift, but not too much duration, some of the milder JUN profiles should work well, they are often copies of Cosworth profiles, and seem to give excellent results. You may well need to use their designated springs and maybe do a bit of valve seat machining work. Running a bigger single turbo would allow you to be far more adventurous with cams.

[Nathan]

Our reccomendation is HKS 256/264 regardless of turbo spec unless you are going for serious power (650bhp+)

This setup is proven, works well and idles perfectly. They are good enough to make 600bhp on a big single or twin yet work fine on stock turbos. They also drop straight in without the need to mess with shims, valve springs or spring fitted lengths.

Make life hard for yourself if you want but unless you want crazy power for the road (in which case we would run 264/272- which also drop straight in incidentally) I would go for the known combo and was perfectly happy with my own 256/264 setup and it was quick enough for me http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/wink.gif

We have actually used 272/272 before but idle is noticeably bad and even the 264 inlets can be a tad annoying.

Regards,

Nathan.

[wez]

Hello Nathan,

Thanks for the info, I am guessing that you guys at TDI have had experience with both 256/264 and 264/264 setups, what are the differences, power/torque response etc?

I am not too worried about the idle as I can just increase this a little using the AEM so not really an issue.

Once again thanks for the info.

Regards

Wez
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[Nathan]

Wez, it's not easy to quantify which is why I didn't go into any more detail on previous posts. The luxury of the information you are asking for simply won't be too easy to come by, and to be brutally honest I think you are looking into it far more deeply than you need to anyway considering the differences between the two, especially at the power levels I think you are after.

IMO, the difference between a 256 and a 264 inlet will only be really noticeable above 600bhp.

If you are totally unconcerned about your idle then a 264 might be a better bet. Personally I don't consider the power gain to be enough to offset the slightly lumpier idle but then I am very fussy when it comes to things like that.

Putting power figures on it would be nigh on impossible. I don't believe we have ever tried a direct comparison on a stock-turboed car, and above 600bhp we have always used more boost than the usual 1.4 so again a direct comparison is unknown. However, from experience, I think you'll be hard pushed to tell the difference between a 256 and a 264 on OE turbos, big singles or twins up to 1.4 bar.

That said, the small drawback of a very slightly lumpier idle may swing it for you. Ultimately, I guess you have to ask yourself what bhp ceiling you are likely to want.

Regards,

Nathan.

[wez]

Once again thanks for the info ?http://www.mkivsupra.co.uk/iB_html/non-cgi/emoticons/buttrock.gif

I have a HP target of around 600- 650 running from a small to medium sized single turbo.

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