Fast road camshafts

[Mark 4]

I know that cams have been mentioned before but has anyone actually managed to source any?
Would anyone be interested in a group buy if we found someone to make them ?

[Wodjno]

http://www.rpw.com.au/shop/index.php?option=com_virtuemart&page=shop.product_details&flypage=shop.flypage&Itemid=31&category_id=156&product_id=1329 (http://www.rpw.com.au/shop/index.php?option=com_virtuemart&page=shop.product_details&flypage=shop.flypage&Itemid=31&category_id=156&product_id=1329)

http://www.rpw.com.au/shop/index.php?option=com_content&task=view&id=111&Itemid=25 (http://www.rpw.com.au/shop/index.php?option=com_content&task=view&id=111&Itemid=25)

[Mark 4]

Cheers Glenn. :2thumbsup

[Nutter_John]

make sure if you get cams them provide you with shims , and you'll also need something to adjust the fueling

[Mark 4]

Yup, it's all on the shopping list John.

[Nutter_John]

I'm sure that list is very long :D

Just as mine is , maybe we should compare sizes :p

[stuartturbo]

Is it worth trying the exhaust cams off the V6 na as this is a good mod that worked well on the vauxhall turbo engines
Could be a free worth while mod if durations and lifts match

[psbarham]

Is it worth trying the exhaust cams off the V6 na as this is a good mod that worked well on the vauxhall turbo engines
Could be a free worth while mod if durations and lifts match

guaranteed not to work, the N/A's are single cam per head

[stuartturbo]

thought there might be a twin cam jobbie

[Subaru ETA]

yeah we did this on my matat CA18DET. but yeah, the na v6 being a sohc engine would cause some probs!

[Eurospec]

guaranteed not to work, the N/A's are single cam per head

Its a good idea though.

You can do this on the GTO TT's using the NA cams in the TT's. Ultimately the mod was dissproven- but for the wrong reasons if you see what i mean.

Theory was that the NA cams had more overlap in them. Meaning the inlet and exhaust valves were both open for a fraction during the inlet stroke. Theory being that the out flowing exhaust gasses help to suck the inlet charge into the cylinder. Ultimately, this does work, and has the effect of a chunky increase in top end power at the expense of mid range torque. Boost does drop off (since you are now pushing a little unburnt mixture into the exhaust on the inlet stroke) but you do gain power without upping the boost to compensate.

The theory didnt hold in GTO's since it turned out there was no more overlap in the NA cams- infact iirc there was less.

Still if you want an idea of what difference it makes, i used to run std gto cams at std timing and my termnial 1/4 mile speeds (a good indication of horespower) were normally 128 ish mph. We added 4 degrees of overlap with vernier pulleys and trap speeds went up to 131ish mph. 3mph doesnt sound like much, but over that time and distance it is! Its probably 20bhp or more.

Cheers,

Ben.

[Mark 4]

Checked with RPW on the spec of their cams and they advised:

"We usually make them to a HKS 272 duration / 300" valve lift which has proven itself time after time"

So it looks like we have a choice of standard or these. The problem is though that I do not know if these are the best profiles/lift to go for. Years ago for bikes and also some cars there were choices from mild to wild so I have contacted a local manufacturer who cam make anything I want from billet steel.

So, can anyone offer me some guidance Pros vs. cons of differing duration/lift/overlap.

Cheers guys.

[Nutter_John]

Mark may be worth having a chat with Kevin @ AP motors as he is one of the only people in the UK I know off that has gone with uprated cams .

Personally if it was me I would be looking at getting everything else sorted first , get the car running to it's max , then look at doing cam's etc . But i can also understand the logic behind doing it up front as it's just one build then

[Wodjno]

Mark may be worth having a chat with Kevin @ AP motors as he is one of the only people in the UK I know off that has gone with uprated cams .

I thought Bonsai Boy had uprated cams in his Leggy :thinking:

[Mark 4]

Yea, that's the thing John. I've sorted out a runabout and the Vr4 is slowly getting stripped out. I only really want to do this once but do it properly which is why I am courting as much opinion as possible. After all I am relatively new to the VR4 and a lot of you guys have so much more experience.

[zentac]

I had some reprofiled by kelford cams in auz (or nz), but when I went to fit them one of them was slightly bent so we never fitted them. I was thinking about sending some off to piper to get some billet ones made up.

[bradc]

Mark, Dave at RPW has said the price is about $2500 AU per set of 4 cams if you are interested.

[Mark 4]

Cheers Brad. Gonna hang fire for a while and see what other options I can turn up.

[zentac]

to resurect an old thread, we have put in some rpw cams this week, and already you can tell the car is breathing better. The gas is getting out easier, and the turbo is spinning up quicker.

Just doing some mapping on the road and we will be at the rollers on the 17th.

[Turbo_Steve]

Hi Zentac:
I think we'll be very keen to see a dynograph of what they've achieved!
What duration did you go for? I know you're headed off down the monster blower route, so 272s would not be unreasonable in your car.
I'm always worried that something as wild as a 272 will ruin the cars road manners: Everything I've used with more than 264deg seems to feel a little gutless at low RPMS before boost...though I've never tried them in a V6.

[zentac]

mine are the HKS 272 profile, its a little lumpy at tickover but not too bad, we have had to take loads of fuel out of the map so far just for normal road use.

[bradc]

Any chance you'd be able to put up a video?

My Autronic has the car set to idle at about 1100rpm anyway, so it doesn't worry me if it is a bit lumpy at 650rpm or so. I think the more wild cams will be masked by the small turbos and extra capacity+cylinders anyway compared to say an EVO

[zentac]

we were having problems getting the gasses out of the engine with standard cams with 515bhp, the heads have been ported but we were still on standard cams. I will get a video up as soon as I can but off to nurburgh on wednesday so it probably wont be until I get back.

[bradc]

ok cool :)

[Mitsiman]

Will be interested to see your results for sure.

And for those that are confused, the HKS 272 profile is our favourite, but we also do a 264/272 profile as well and smaller. The HKS one is the one we sell the most of and is definitly the recomended choice for high horsepower applications.

And you don't need any shims with our units as these are brand new billets, not regrounds.

[Mark 4]

Will be interested to see your results for sure.

And for those that are confused, the HKS 272 profile is our favourite, but we also do a 264/272 profile as well and smaller. The HKS one is the one we sell the most of and is definitly the recomended choice for high horsepower applications.

And you don't need any shims with our units as these are brand new billets, not regrounds.

What is the lift on these ?

[Mitsiman]

they should be 0.300" lift if I recall correclty

[Mark 4]

I make that 7.62mm (give or take)

According to Zentacs sig he was running 265° and 10.8mm lift.

So, 7.62 sound a bit tame.

[Eurospec]

272's are fine. Idle is a bit lumpy, but thats about it.

The thing is though, dont go thinking cams will give you boat loads of power on their own. They dont. Some - yes, but not lots.

Normally you use cams to change the shape of the power curve to move the power around to be more where you want it.

Cheers,

Ben.

[zentac]

I make that 7.62mm (give or take)

According to Zentacs sig he was running 265° and 10.8mm lift.

So, 7.62 sound a bit tame.


the 265's were the original re-grinds I had done and one was bent so they never got fitted.

[Mark 4]

the 265's were the original re-grinds I had done and one was bent so they never got fitted.

So what lift do you have on the 272's please ?

[zentac]

Quick update - these engines NEED cams

Just back from the rollers, and I currently have the same power as last year 515bhp on pump fuel but on 1.5 bar :D (was 1.8 last year) so doing some more mapping today (need 2bar +) ready to race sunday..... I will just need to hold on tight and shut my eyes! :helmet:

The only thing we have changed since last year are cams, valve springs & flywheel.

[Turbo_Steve]

Good info! Thanks Zentac!
So that's the HKS cams with 272 duration on both inlet and exhaust?
What's it like to drive "off boost"?
I don't doubt for a moment that at 500+bhp the cams are holding it back, but longer duration moves power "up the curve" (even more so on a turbocharged engine) so my concern is that a car that usually has children & shopping in, how big a compromise are they, and would something a little milder make more sense for the "daily driver" bridgade?

Or should I just buy an RS4 Avant? :D [/dreaming]

[zentac]

we are still mapping it but the 515bhp graph we had before was almost identical to the graph we currently have but now on lower boost. it was down about 10 lb/ft across the range, but we were only half way through mapping and hadn't really started putting ignition in which would have brought it back.

[Mitsiman]

sounding good. You are correct that the 272 hks profile is a "Mild" camshaft, its primary design is for road racing so big power spread, fat torque curve and good throttle response.

We can make larger profiles for sure, but they become strictly high rpm horsepoer enignes rather than a road rcing engine setup. Keep us up to date with the results