Which Camshafts?

[Jamtime]

Hi there,

I have an R32 gtr and i'm planning a big rebuild. I'm looking for around 370rwkw every day car with maximum response.

I will be running HKS 2.8L Stroker with HKS Gtrs Turbos plus lots more. Can anybody recommend camshafts or a camshaft kit that would best be suited to my needs.

Thanks,

Jamil

[R31Nismoid]

This should be a good debate, always is

Some will say stock, some will stay 260's, some will say 270's+

One thing however is for certain. Your turbo choice for 370rwkw - is bad.

Those turbos are 450rwkw+++. So there is little point in using them for that power goal.

If you want max response, you want the Garrett -5's (AKA HKS2530).

They will be coming into boost in the mid-high 3000rpm range, pull to 8000rpm and make you a lazy 400rwkw.

[N1GTR]

Yeah this will be a good thread!

Heaps of people have tried heaps of different setups and will have different things to say.

Ive got a 3L and GTRS's with 270's and changing to 260's to bring the power on a bit earlier

[N1GTR]

Where do you live? A good way is to ask people locally to take you for a drive in different setups so you can really feel what its like

[Swiper the Fox]

Yeah this will be a good thread!

Heaps of people have tried heaps of different setups and will have different things to say.

Ive got a 3L and GTRS's with 270's and changing to 260's to bring the power on a bit earlier

ive tried 260's with RS's...they were rubbish.

transformed the car with real cams installed and a proper head. Brought the power on 1000rpm earlier. This was an actual back to back test on the same engine/car and dyno with the same operator. Even one of the most experienced GTR tuners in the country thought his dyno was playing up as the difference was unbelieveable. He rolled another car on to check it was reading right, then rolled ours back on and it made the same power (less 2KW).

some people don't actually understand how a forced induction engine works...with a 26 stroker you would be mad to do what you have suggested above as it will leave a massive hole in your torque curve and leave you wondering why its not performing. 260's have nowhere near enough valve lift to move the air required for those turbo's. Their is a fella up here in qld who just tried the above with his 26/30 and went backwards as i told him it would. His T51R that he installed after he decided to ditch the RS's for actually came on earlier as it was recieving double the cylinder pulses the RS's were for each engine revolution keeping the turbo shaft speed high. The RS' sare not an easy turbo to get right when using in a twin combo...but when right they are outstanding. Over 500AWKW at 25psi, a 5000rpm curve of peak torque and 9 second drag passes out of a 1500kg car is my proof that i know how it needs to be done.

Jamil, if you need hand with the build send me a PM.

Edited January 13, 2010 by DiRTgarage

[NYTSKY]

Yeah this will be a good thread!

Heaps of people have tried heaps of different setups and will have different things to say.

Ive got a 3L and GTRS's with 270's and changing to 260's because i cant handle the awesomeness

Fixed.

[N1GTR]

*sigh* ....well this was going to be a decent thread.

Good luck with the build

Btw Dave, you can have a drive of my car in about 2 months when it comes back home. You'll take back that comment pretty quickly

[Swiper the Fox]

*sigh* ....well this was going to be a decent thread.

Good luck with the build

Btw Dave, you can have a drive of my car in about 2 months when it comes back home. You'll take back that comment pretty quickly

What?...thread is now indecent because you don't agree with something someone has said. So there is something a little wrong with someone sharing knowledge that has been there before. You have a point though...an engine that produces over 1200nm of peak torque at 4500rpm, that revs to 9500rpm and makes over 1/2 a megawatt at the tyres is so indecent it should be considered porno.

Edited January 13, 2010 by DiRTgarage

[NYTSKY]

The sound of 270s on an RB is porn

Back on topic:

As Nismoid said GTRSs are too big for 370awkw, for response you need to make your target power level with the smallest turbo/s.

But what power you will get will never be enough. If this build is for "real" i would put on T51R (KAI). Will make over 400awkw and have fairly good response.

And have a set of 260 degree 10.25 lift cams in there.

[Nee-san]

I'll tell you one thing, nothing starts arguments like a good discussion about camshafts.

I'm currently running a 26 with 264IN and 272EXH and I've had every man and his bloody dog try and give me advice, drives you mental after a while.

My advice is to look at the guys who have been there and done it and generally it will save you a whole lot of coin.

Back OT, I agree with R31Nismoid and as im sure the other gentlemen in this thread will tell you, your better off choosing a turbo setup on the smaller end of the scale to acheive this power level (read Not GT-RS) as you have stated response is your ultimate goal.

Cheers,

Mitch.

[zebra]

an engine that produces over 1200nm of peak torque at 4500rpm, that revs to 9500rpm and

1200 newtons of tractive effort...not actual torque at the crank

I still dont see how massive cams can bring the power on earlier...its goes against every thing related to engine tuning i know.

More lift plus more duration = more power at high revs and less down low.

Big cams need high compression to work properly...so on a turbo car that means more air flow, it might make more power at less +ve manifold pressure, but ill bet the turbine shaft speeds are higher.

I feel that a 264/268deg total duration (230/235 @ .050) with 10mm lift should still give reasonable cylinder filling at normal street revs while still allowing the 2.8 to dig deep at higher revs.

Make sure you do somthing with the ports aswell as discuss cams with your head guy, not the bloke selling you the HKS turbos with about 100% mark up. As most mechanics will tell you what ever you want to hear to get at your credit card.

[R31Nismoid]

^^ Doesn't mean they offer anything

Agree though, bad turbo for 370rwkw regardless.

ive tried 260's with RS's...they were rubbish.

transformed the car with real cams installed and a proper head. Brought the power on 1000rpm earlier. This was an actual back to back test on the same engine/car and dyno with the same operator. Even one of the most experienced GTR tuners in the country thought his dyno was playing up as the difference was unbelieveable. He rolled another car on to check it was reading right, then rolled ours back on and it made the same power (less 2KW).

some people don't actually understand how a forced induction engine works...with a 26 stroker you would be mad to do what you have suggested above as it will leave a massive hole in your torque curve and leave you wondering why its not performing. 260's have nowhere near enough valve lift to move the air required for those turbo's. Their is a fella up here in qld who just tried the above with his 26/30 and went backwards as i told him it would. His T51R that he installed after he decided to ditch the RS's for actually came on earlier as it was recieving double the cylinder pulses the RS's were for each engine revolution keeping the turbo shaft speed high. The RS' sare not an easy turbo to get right when using in a twin combo...but when right they are outstanding. Over 500AWKW at 25psi, a 5000rpm curve of peak torque and 9 second drag passes out of a 1500kg car is my proof that i know how it needs to be done.

Jamil, if you need hand with the build send me a PM.

What cam's was this running?

Not supersize-me cams that's for sure....

Factory OEM cams

So it's very much as i said earlier - a very debatable topic that will go every which way like shit off a fan.

Everything works for everyone, how they take choice to do so.

But come on - does it need to go to PM? Lets keep it out in the open (and stop editing your posts )

[wolverine]

Apart from standard cams what else was used on the engine?

[R32 Driver]

What Specs are the standard rb26 cams?

[Swiper the Fox]

Apart from standard cams what else was used on the engine?

the amount of r & d that went into building that engine if put into a $$ figure was about $200K. That was stated directly to me in person by the engine builder.

Zebra your coventional thinking you have quoted is correct on a vacuum drawing engine (atmo). It doesn't necessarily go the same way with forced induction. Would you run a small cam in an atmo engine that runs 15:1 static comp and expect it to make lots of power early...no way. How do you expect to get good cylinder fill and properly burn the mixture.

The thread was about RS' turbo's on a 2.8ltre. I wouldn't contemplate running RS's in a streetcar as it takes a big dollar head to compliment them...but if dollar figure is not an issue...yeah go for it...if not put -5's on it and enjoy a car that will fly under the radar and spend the saved $$ on a good brake kit for track racing it every now and then.

[R31Nismoid]

the amount of r & d that went into building that engine if put into a $$ figure was about $200K. That was stated directly to me in person by the engine builder.

Zebra your coventional thinking you have quoted is correct on a vacuum drawing engine (atmo). It doesn't necessarily go the same way with forced induction. Would you run a small cam in an atmo engine that runs 15:1 static comp and expect it to make lots of power early...no way. How do you expect to get good cylinder fill and properly burn the mixture.

The thread was about RS' turbo's on a 2.8ltre. I wouldn't contemplate running RS's in a streetcar as it takes a big dollar head to compliment them...but if dollar figure is not an issue...yeah go for it...if not put -5's on it and enjoy a car that will fly under the radar and spend the saved $$ on a good brake kit for track racing it every now and then.

Same could be said for a lot of motors, workshops spend time and money to learn over the years.

This is the end result. To have it "built" would not cost 200k once knowledge is known, which it is.

Agreed about RS's for street etc, simply not worth it for the build here IMO, even for the street if there was enough cash simply because there is something (-5's) that will outperform the GT-RS's in everyway @ 370rwkw! Hell even 440rwkw if you were to get excited

[STATUS]

in about a fortnight we will be doing a back to back test on std camshafts vs some 264 9.8's (both will have extensive dialling on the dyno to maximise area under the curve not peak), test car makes around 420-430kw so it may be of interest, then again it may not. I have no issue sharing the graphs.

[R31Nismoid]

Depends on the headwork as much as the cams.

One set might look nicer on a dyno, but how is it on the street (and vice versa). Transient response etc borders on impossible to see on a dyno, but you can feel it on the street etc etc.

Also being one item of head work might work well with stock cams, but another avenue works better with larger cams.

It's all so dependant on many variables that some back-to-backs are hard to draw concrete conclusions about for this stuff.

If your motor build/headwork respond to cams, then cams it is. If your motor build/headwork dont respond to cams due to the nature of the headwork, then no cams it is

[STATUS]

Depends on the headwork as much as the cams.

One set might look nicer on a dyno, but how is it on the street (and vice versa). Transient response etc borders on impossible to see on a dyno, but you can feel it on the street etc etc.

Also being one item of head work might work well with stock cams, but another avenue works better with larger cams.

It's all so dependant on many variables that some back-to-backs are hard to draw concrete conclusions about for this stuff.

If your motor build/headwork respond to cams, then cams it is. If your motor build/headwork dont respond to cams due to the nature of the headwork, then no cams it is

true and everything should be taken as only informative not definative as with everything engine related, but it gives a solid idea as to where the curve shifts with just a simple cam change on this particular setup.

Depending on dyno you can actually do a drive cycle through each gear (timed and loaded the same as the street) and look at the effect lower gears (lower/shorter load) have on the afr's. We looked at one of the race logs from PI and matched the time in gear so we could "better" replicate the added loads of aero drag etc

You can also set it up a cruise load then nail it (in any chosen gear) and launch into a loaded pull, this allows better tuning of said transients... not perfect but damn close.

Would love to see your car on the dyno one day Ash, you can even provide a operator if you wish, would be good to set a known comparo for all the guys on here that dont seem to get the gtss's working right (ive heard your is very well setup).

[R31Nismoid]

Oh ye... if its a stock head - very good comparo being most heads would be near enough to identical

Ye i'm still coming past - WHEN i get the car back. Severe delays with Nissan & parts not arriving (joy of owning a HR31 & certain parts i just cant use GTR parts for lol), its just gathering dust atm so i will 100% call in.

But its sadly going to be a few more weeks yet. But i'll be in touch. I'll do Racepace, you, Drifty all in a day if i can wangle it just for interests sake