Camshaft Discussion

[exahsix]

OK as the topic states, how about some technical discussion on Camshaft selection for the T.

I'm about to put a new bottom end in the car that should hold well over 400rwkw and have done all the other mods - big APS cooler and reversed standard intake plenum to shorten the airflow route, all big pipes, K & N filter etc. Exhaust is 4" dump, 5" cat, twin 2.5" pipes thereafter. So in terms of airflow into and out of the head I should have pretty much everything you can get (bar an aftermarket exhaust manifold).

Now I can see by lots of results on the forum that many people have achieved a PEAK power of 400RWKW and over on the standard cams. I mean you can basically wind up the boost to infinity to get a peak power reading on a dyno until it goes BANG.

What I want to know is, will fitting a set of aftermarket cams change the low-down or high-up performance of the motor? Will it make boost come on earlier?

I think there are a few different cams available - Atomic makes a set, I bet Nizpro have a set and CV also get cams made to their spec.

What are peoples experiences with having different cams fitted, particularly at the high power levels?

What are tuners experiences with tuning these different cams - what about the cam advance and retardation as well? What effect does ithave on the rest of the tune- spark advance, tip-in, boost levels, etc etc.

Perhaps we can have some good technical discussion.............and maybe some dyno graphs - Simon Extreme I know you've tuned a couple of them - what are your thoughts?

[crazed1]

good topic

[rapidchris]

im very interseted as well as I have had cams put in

[F6 RAPID]

My 2 cents for what it's worth....................

Personally, after your cat, go a four inch single system - it flows more than a dual 2.5".

Cams, from my understanding, the ones available all push the power envelope up further in the rev range - which is not what you want for a street car. Talking with Simon (Gishus), these engines tend to buzz themselves apart after 6600rpm so you really don't want a rev limit higher than that and if you can make the power before that, you certainly don't need cams.

Make sure you put in billet oil pump gears before I forget otherwise forget revving your engine to 6600 !!

Quote "Now I can see by lots of results on the forum that many people have achieved a PEAK power of 400RWKW and over on the standard cams. I mean you can basically wind up the boost to infinity to get a peak power reading on a dyno until it goes BANG"

I believe the standard turbo has nothing left for me. I think I could actually disconnect the wastegate and it still will not throw any more boost into the motor because it simply has not got any capacity left to do so. So, if you are after my sort of power (Approx 409rwkw's depending on which dyno!) the standard turbo will do just fine and you retain an absolutely awesome kick down low.

That is why I am now going to the Nizpro exhaust manifold, bigger turbo and external wastegate - it does have the capacity to flow more air! Simon (@ Xtreme) has managed 507rwkw's with this setup and de-tuned?! it to 470rwkw's until our bigger injectors get here BUT, this is still with the standard cams. So ultimately, you really don't need them (cams) with either set-up IMHO and from practice. I believe it only makes the car harder to tune and puts the power up where you don't want it.

[exahsix]

Thanks Shane, excellent reply covering most of the issues in the discussion.

So from your input, standard cams and turbo/manifold for approx 400rwkw is the go, retains all the driveability.

On the subject of oil pump gears (which seem to cost $$$$$$) I had a discussion with Con & Vic and they are of the opinion that this is really only necessary for manual cars, not auto like mine - as it's the 'shearing' stresses from rev and dump that seem to break them.

Anyone else care to share their experiences on these topics?

[F6 RAPID]

Mate, definitely standard cams/exhaust manifold/turbo will suffice for 400. All of your driveability will be maintained with that huge mid-range hit - if you like that sort of thing.......

Interestingly though, with the new exhaust manifold and bigger turbo of Simons(xtreme), it takes less boost to make heaps more power - just more air flow and the manifold helps spin it up I suppose. It want to - you think oil pump gears cost....

What have you done for the intake? Are you running the Nizpro gear incl intercooler? This will need to be sorted if not.

I know the oil pump gears are exxy, but while you have to engine apart, it is a very worthwhile safeguard! Much easier to do it while apart than have them fail and starve your brand new motor of oil........................

[DAWSEY]

Thanks Shane, excellent reply covering most of the issues in the discussion.

So from your input, standard cams and turbo/manifold for approx 400rwkw is the go, retains all the driveability.

On the subject of oil pump gears (which seem to cost $$$$$$) I had a discussion with Con & Vic and they are of the opinion that this is really only necessary for manual cars, not auto like mine - as it's the 'shearing' stresses from rev and dump that seem to break them.

Anyone else care to share their experiences on these topics?

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I would get it done when the motor is out anyway.

if your pump goes like mine did. you will have to buy cams anyway as the head will be f*cked...

I put cams in mine only because I had to buy new ones...(oil pump went)

con can get the same power on lower boost with my cams which puts less stress on the motor...

at the same time if 400rwklw is your target then you will not need them

[F6 RAPID]

if your pump goes like mine did. you will have to buy cams anyway as the head will be f*cked...

Do the oil pump gears!!!

[F6 RAPID]

Ignore what I said about your intake - re-read your post............my bad!

[exahsix]

FKN oil pump gears!!!! Just seems like such a lot of money for an insurance policy.

I could spend that money on a 100 shot bottle of DBOSS