Jump to content
SAU Community

GT30 Cam Selection

masTers

By masTers,
in Engines & Forced Induction

 Share

Recommended Posts

masTers Mentor

masTers

Posted
Posted

Currently building up a RB30-DET, and its come time to choose cam shafts, now against alot of peoples advice, im still running with a low mount GT30, and was just curious cam selection?

A few people have recomended the Tomei Poncam's but was wondering what others think. I defiently want to go Tomei, be it PON or PRO cam.

Im using the R32 RB25-DE head, so im limited to RB20 cams right?

Link to comment
https://www.sau.com.au/forums/topic/72537-gt30-cam-selection/
Share on other sites
R31Nismoid Grand Master

R31Nismoid

Posted
Posted

If its an RB25 head, you need RB25 cams.

Although, with a GT30 on an RB30det, you will not need cams in the slightest.

Its gonna come on so early that in my opinion there is no need at all. Spend the $$ one something else will gain more benefit

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

The stock heads are fine upto 300rwkw, mine is going quite well now without problems.

Yeah cams might bring it on a bit earlier etc. But for the price i can spend it elsewhere and get more of a gain.

with a GT30 he wont be pushing much more than 300rwkw if that.

masTers Mentor

masTers

Posted
  • Author
Posted

I dont seee how an N/A head is capable of 300rwkw? Dont forget that this is the R32 n/a head NOT the R33 one. According to CUBES guide and a few other sources, the cams and springs in this head are useless for boosted applications and are interchangeable with RB20-DET cams and springs.

I thought due to the VVT the R33+ RB25 Cams would be unsuitable?

rev210 Grand Master

rev210

Posted
Posted

I would strongly suggest a camshaft upgrade to cater for the larger displacement. There are far greater benifits again for doing this to a big breather like the RB30 hybrid. The Rb30 should quite happily live with larger cams than an Rb25 and the spread of power increase will be more than worth the expense. Even if you go for the pon cam 260deg 9mm lift units, which should not tax the factory springs much given the rpms are lower and the lift not too radical, and the gains will be substancial over the nanna grade cams the Rb25 has from factory.

Even if you had an Rb25 stocker a cam upgrade does wonders when it's set up right.

180bfj20det Community Regular

180bfj20det

Posted
Posted
R31 could u explain why he wont need cams?

But if he were using an rb25 he would benefit more from cams?

I would be interested to know ;)

I think what he is saying is that the GT30 will already be at its limits with the flow capacity of the hybrid 30/25 and that increasing the flow with bigger cams would only change the power delivery more or less rather than outright power. Rather than cams, get at least a GT3540 or personally Id go bigger. Here you will make gains and then later down the track even more with cams but cams with a GT30 are a waste of time and money on that awesome high flowing hybrid. YOU NEED BIG TURBO for this engine....maybe seriously get another GT30, use 0.63 housings on both and youll want cams then....but youll make HUGE power tho with considerable lag I imagine (5.5k up). Im sure there is a GTR that has already this conbination making +400rwkW.

Gradenko Mentor

Gradenko

Posted
Posted
If its an RB25 head, you need RB25 cams.

RB20 cams (aftermarket or not) will fit.

Although, with a GT30 on an RB30det, you will not need cams in the slightest.  

Its gonna come on so early that in my opinion there is no need at all. Spend the $$ one something else will gain more benefit

Are you joking? Because I'm not laughing.

Cubes Grand Master

Cubes

Posted
Posted

Its an R32 RB25DE head.. You will need the R32 RB20DET cams.

Anything to increase the airflow and reduce the boost required is a good thing.

Increase only the lift and you will increase the average power under the curve, increase only the duration you will increase the rpm at where peak power is made.

Also larger duration hence slightly more overlap does not work well with a restrictive turbine housing and or exhaust.

The N/A stock cams are not useless, however the springs over 17psi are.

The N/A springs don't have enough seat pressure and cause valve float on the inlet.

Replace the springs with a turbo set of springs and the motor will be fine to run big boost.

There's a GT35 internal gate .82 on a Rb30det getting around on this board by the name of Sky30.

Stock cams, stock exh. manifold, gtr valve springs made 290rwkw @6000rpm on ~19psi.

He has a set of Tomei PonCams 260duration coming.

It will be very interestering to see the boost drop and power go upwards. :cheers:

I have a .82 ARB machined exhaust housing to suit a GT35R, it has provision to bolt an external gate on and bolt up to the stock exh. manifold. It isn't optimal.

The same exhaust housing on another RB30DET with 18-19psi it made 306rwkw. With a garrett gt35r .82 exhaust housing, aftermarket manifold setup properly with the wastegate it made an extra 20rwkw on the same boost.

Obviously the GT35R's love the high boost 25psi range. They are rather efficient up that are of the compressor map.

You select a turbo to suit your power requirements.

If up to 300rwkw is what you want then select a GT30R, if you want over grab your self a GT35R.

The trick with the RB30 is to get a nice free flowing exhaust and turbine housing.

A bare minimum of a .82 exhaust a/r and a 3.5" exhaust (nice big center resonator & rear muffler) will work well with the RB30DET.

NickR33 Grand Master

NickR33

Posted
Posted
I would strongly suggest a camshaft upgrade to cater for the larger displacement. There are far greater benifits again for doing this to a big breather like the RB30 hybrid. The Rb30 should quite happily live with larger cams than an Rb25 and the spread of power increase will be more than worth the expense. Even if you go for the pon cam 260deg 9mm lift units, which should not tax the factory springs much given the rpms are lower and the lift not too radical, and the gains will be substancial over the nanna grade cams the Rb25 has from factory.  

Even if you had an Rb25 stocker a cam upgrade does wonders when it's set up right.

It sure does:)

and Ash, your car really sounds like its got aftermarket cams?

RS500 Experienced

RS500

Posted
Posted
 

 

I have a .82 ARB machined exhaust housing to suit a GT35R, it has provision to bolt an external gate on and bolt up to the stock exh. manifold. It isn't optimal.

The same exhaust housing on another RB30DET with 18-19psi it made 306rwkw. With a garrett gt35r .82 exhaust housing, aftermarket manifold setup properly with the wastegate it made an extra 20rwkw on the same boost.

 

dude,

in my experience with a Garrett GT3040R (ARB exhaust housing), i would recommend u get rid of it as it poses a great restriction to the flow of the turbo's gasses.

i would recommend using a genuine GT exhaust housing which was designed for the flow and dynamics of the GT35R exhaust wheel.

the reason i say this is b/c when i had my A/R .82 ARB housing on my turbo (as above), i couldn't make any decent power, even at 20psi, and the back pressure was high (almost 2:1), whereas with the genuine GT A/R .63 housing, we saw the back pressure drop dramatically (almost 1:1) and power picked up noticably.

it's only my opinion, but yeah it's based on my own experience.

Cubes Grand Master

Cubes

Posted
Posted

I've since decided to get my self a HKS3037ProS from japland.

It will make the power I want and give me the look I want. :cheers:

If it wasn't for the police here in SA I would most definitely go for an external gate etc etc.. After having the hood popped the other night It's really made me thing I should step back and go the 3037 with its 45mm internal gate.

The ARB exhaust housing works and makes the power but obviously isn't optimal.

Any 1 want to buy it?

Its got the flange to bolt on a external gate so it will allow you to bolt a GT35R up to the stock exhaust manifold. :P

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

nope. totally stock down to gears and everything.

Only changed the bottom end gear which isnt power gaining, just power withstanding :D

I kinad sounds like i have cams just before it comes onto boost/gate as thats where the VCT comes in and when its just feeding in 17-24psi it gives that impression

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      R34 Gtt Wheel Offset Advice

      By GTSBoy · Posted

      I think my main complaint with your idea is that there is a veneer of idealism spread across it. You want the simple numbers to make it easier, but all they will do is make it easier for someone to come to the wrong conclusion because the fine details will kick them in the nuts. As it is right now, the tiny bit of arithmetic is NOT the obstacle to understanding what will fit and what will not fit. The reality of trying it is what determines whether it will fit. If you had a "standard rule" that R34 GTT guards have that magic 100mm space from the hub face to whichever side you were worried about, and someone said "excellent, this wheel is only 98mm in that direction, I'll just go spend $4k on them and jam them on my sick ride".....they would just as likely find out that the "standard rule" is not true because the rear subframe is offset to one side by a fairly typical (but variable) 8mm on their car and they only have 92mm on one side and 108 on the other.
    • Kinkstaah
      R34 Gtt Wheel Offset Advice

      By Kinkstaah · Posted

      It still combines inches with mm, especially when you have .5 inches involved, and mm and inches that can go in either direction. This would give a clear idea on both sides of the rim, right away, with no arithmetic. Even better if somebody gives you the dimensions of the arch of multiple cars. i.e GTR may be 125mm, a A80 Supra may be 117mm, or something along those lines. Yes, you can 'know' that going from a 10in rim to a 10.5in rim with the same offset moves both sides about 6mm, but you still have to 'know' that and do the math. Often it's combined. People are going from 9.5 +27 to 10.5 +15. You may do the math to know it, but if it was going from (I had to go look it up to be sure) 241mm/2 - 27 - 93.5mm from the center line to (more math) 266/2 - 15 (118mm) from the center line. Versus 93mm vs 118mm. It's right there. If you know you have a GTT with 100mm guards you can see right away that one is close to flush and the other absolutely won't work. And when someone says "Oh the GTR is 120mm" suddenly you see that the 10.5 +15 is about perfect. (or you go and buy rims with approximately 118mm outward guard space) I think it's safe to say that given one of the most common questions in all modified cars is "How do offsets work" and "How do I know if wheels will fit on my car" that this would be much simpler... Of course, nothing will really change and nobody is going to remanufacture wheels and ditch inches and offset based on this conversation :p We'll all go "18x9+30 will line up pretty close to the guards for a R34 GTT (84mm)" but 'pretty close' is still not really defined (it is now!) and if you really care you still have go measure. Yes it depends on camber and height and dynamic movement, but so do all wheels no matter what you measure it for.
    • GTSBoy
      R34 Gtt Wheel Offset Advice

      By GTSBoy · Posted

      But offsets are simple numbers. 8" wheel? Call it 200mm, near enough. +35 offset? OK, so that means the hub face is that far out from the wheel centreline. Which is 2s of mental arithmetic to get to 65mm to outer edge and 135mm to inner. It's hardly any more effort for any other wheel width or offset. As I said, I just close my eyes and can see a picture of the wheel when given the width and offset. That wouldn't help me trust that a marginal fitment would actually go in and clear everything, any more than the supposedly simple numbers you're talking about. I dunno. Maybe I just automatically do numbers.
    • silviaz
      R32gtr sputtering and stalling

      By silviaz · Posted

      Ah ok interesting to know.
    • Kinkstaah
      R34 Gtt Wheel Offset Advice

      By Kinkstaah · Posted

      Sure! But you at least have simple numbers instead of 8.5 inches +/mm, relative to your current rims you do maths with as well, and/or compare with OEM diameter, which you also need to know/research/confirm..
×
×
  • Create New...