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272in/264ex vs 256in/264ex cam setup test results


Ian C

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Great write up and thanks for testing Ian.

 

Another BPU question. I was considering mild cams, ie 256/264. I understand what you say about the stock ECU not knowing that the extra breathing is up there. How could you overcome this in terms of management? E-ultimate/PFC?

 

And you should post your results on that SF thread, if you havent alraedy.

 

You'd need some way of increasing the fuelling. We got good results with a stock setup by controlling the fuelling above stock boost levels with an E-Manage - by taking fuel out, and letting it go back in as boost go higher, we had a much more controlled AFR and picked up some power on the arse-dyno - but you are on the edge of what the 440s can deliver. Bigger injectors are, as ever, recommended :)

 

Oh, and I daren't post up my findings on the SF thread lol

 

-Ian

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Yeah :( just glad this all came to light before I made the change.

 

Although it looks like it would have still been an improvement over stock cams but other setups work much better.

 

I am looking at going 264/264 now so need to get a new inlet cam.

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Well done Ian - another valuable test you have done. How odd for someone who does not care about members on here.

 

I don't know where such silly ideas come about, but there always seem to be a few around and I am glad you have put a definitive nail in the coffin of this. (It was always clear the exhaust side does not flow as well and needs the help of a matched or even more aggressive cam relative to the intake).

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I got details from someone in the US with dyno plots that shows an increase across the rev range with a 264/264 combo on a PHR Stage 1.

 

No visible losses :D

 

Good to know, thanks :)

 

I'd be interested to know what kind of difference 264/272 would make, I've no idea how the two different cams affect things.

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Good to know, thanks :)

 

I'd be interested to know what kind of difference 264/272 would make, I've no idea how the two different cams affect things.

 

Someone on SF (CHONCO?) has posted up his stock vs 264/272 dyno results...he lost a lot of power low down and then regained/passed the stock cams at about 5000rpm.

 

PS - not on the stock turbos.

 

IMO. THe 256/264 or 264/264 is now the only choice for the street (99%) driven Supra.

 

...if someone would swap Ian's 272in for a 264in I'm sure he'd test it again ;) :p

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So going from Wez' information 264/264 would seem best on a single turbo and possible keep the staggered 256/264 if you're still on stock or hybrids?

 

Possibly...really we need someon to lend Ian a 264in...so that all other things are equal...ie testing on the same car with no other mods.

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brilliant write up there, you're a credit to this forum! :)

 

If you could get the fueling right, what bhp can be released from going to 256/264 from stock/bpu, are we talking much? Same on a single, what bhp does it release in reality or is it more about responsiveness and extending the rev range as much as anything?

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brilliant write up there, you're a credit to this forum! :)

 

If you could get the fueling right, what bhp can be released from going to 256/264 from stock/bpu, are we talking much? Same on a single, what bhp does it release in reality or is it more about responsiveness and extending the rev range as much as anything?

 

It's a bit of a "how long is a piece of string" question/answer.

 

On stock turbo's you won't gain anything really...but they tend to not fall away so badly at high RPM's.

 

Singles...well it depends on which one...etc etc etc.

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In short is the answer basically, a traditional staggered set-up will give you good consistant result.

A reversed set-up will give very good results, but is a lot more difficult to install correctly. If not installed correctly, it can be a good deal worse than a staggered set-up.

 

Does that seem like a fair summary?

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I don't think it's fair. I can't see there being some mythical sweet spot where it's noticeably superior to the 256/264 setup, whereas one or two degrees out and it runs like a dog.

 

I still say that it would be implausible to tune it back to how good the 256 setup is, never mind overtake it. Yeah, it may be better than stock cams but that doesn't mean it's better than any other setup ever.

 

I've done my tests and the results are good enough for me, if anyone else wants to test it, then for chrissakes buy my 272 intake cam off me :)

 

-Ian

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