Power Ceiling Gt3076R

[R32Abuser]

http://www.skylinesaustralia.com/forums/topic/104332-rb30-hybrid-upgrade-all-dyno-results/page__st__20__p__3299027#entry3299027

FYI

[R32Abuser]

Ok so just got off the phone with the builder...

Him and Darren Lewis from Lewis Engines reckon it's the camshafts restricting the power. Darren said that he had tried this combination (RB30DET + RB20DET cams) once before (slight differences) and had this same issue robbing the motor of upto 50kW. I tend to agree as earlier today when the car was on the dyno, no matter how much boost was put into the motor, the power would simply not budge (if anything it would lose power). Considering that both the exhaust and airbox were pretty much eliminated from the equation, to me these symptoms reflect the motor struggling to breathe and hence make decent power. This then could point to one or two problems.

Camshafts or Camshaft timing...

The motor nosed over HARD. It would make 210kW by at 5000 RPM (this is simply peak, motor may of been making that for 500-1000 RPM before that for all I know!), but then would drop down to 170 kW by 5500RPM. Bare in mind my limiter will be set at 7000RPM!

From the guys with experience/tuners, does any of this seem off? Or is new camshafts + adjustable gears the most advisable avenue to go down to fix this problem?

[DVS JEZ]

Ur rev limit seems off. Should be 8000

Cams would be a very good idea. The effort u have gone to to change to rb20 cams etc if funds are available u should get some upgraded cams to suit.

[sriver killer]

This makes me nervous about getting my 25/30 tuned tmrw =[

hope you sort your problem out mate, does it drive/sound normal?

[wolverine]

If others have made more power with those cams it seems to me that something is screwy with the timing still.

[R32Abuser]

To my knowledge, all those who made power with standard cams did so with RB25DE cams. Since we thought that these were part of the previous issue of detonating, we replaced them with the RB20DET cams. However, I think maybe the issue was that the motor was timed incorrectly previously as opposed to the camshafts causing the detonation.

In hindsight, this could have been a bad move, however, my intentions were always to upgrade my cams to aftermarket units/regrinds.

Now the question is...Do I go for a set (which are available now) of Tomei 256deg/8.5mm IN/EX camshafts for $700 and get adjustable cam gears for an extra $250 odd?

OR

Do I go with custom regrinds (of GTR camshafts) which Cubes (Joel) went for - 264deg/9mm IN/EX from Tighe Engineering for about $500 with a set of adjustable cam gears?

[DVS JEZ]

Does cubes' setup have the response and power goals u are chasing? If so then his "should" work if timed correctly

[R32Abuser]

His setup is more or less what I based my choice of equipment on. Its only since hitting issues that things have changed.

All I am doubting is the fact that the motor can be timed incorrectly 2-4 times. It just doesn't seem likely

Power goal is 300RwKw but the main thing is the torque. I was hoping to make around 200 rwkw by 4000-4500 RPM...might be a little ambitious in wanting that

Edited September 13, 2011 by R32Abuser

[TiTAN]

I was hoping to make around 200 rwkw by 4000-4500 RPM...might be a little ambitious in wanting that

turbo should give you that. im on a GT35 and make 200kw at 3800-3900

[R32Abuser]

turbo should give you that. im on a GT35 and make 200kw at 3800-3900

Nice! Might get there after all!

Much headwork done?

[The Mafia]

To my knowledge, all those who made power with standard cams did so with RB25DE cams. Since we thought that these were part of the previous issue of detonating, we replaced them with the RB20DET cams. However, I think maybe the issue was that the motor was timed incorrectly previously as opposed to the camshafts causing the detonation.

In hindsight, this could have been a bad move, however, my intentions were always to upgrade my cams to aftermarket units/regrinds.

Now the question is...Do I go for a set (which are available now) of Tomei 256deg/8.5mm IN/EX camshafts for $700 and get adjustable cam gears for an extra $250 odd?

OR

Do I go with custom regrinds (of GTR camshafts) which Cubes (Joel) went for - 264deg/9mm IN/EX from Tighe Engineering for about $500 with a set of adjustable cam gears?

You're wasting your time getting cam gears with Tomei cams, because tomei make them already set at their best position.

If you get GTR re-grinds, definitely get adjustable cam gears. The user Dale_FZ1 has gone down this road with some great success.

I still think there is something stupid wrong with your setup though, you should be making at least 250rwkw. Your Engine is capable of making 300rwkw set up correctly. And its safe to assume that RB20\25\25NA cams should be able to flow enough gas to get that sort of power. 200rwkw seems like too low of a wall.

Anyway, for the best response, 256 Tomei are great. NIce fat mid range with the ability to spool a turbo quickly.

Get someone to check your timing - someone that knows their shit. Can you get us a video of it breaking down or losing power? I want to hear it

[TiTAN]

Nice! Might get there after all!

Much headwork done?

very little, basic clean up (just taken any burs out), stock valves and stock R33 25DET cams

[Guilt-Toy]

The issue is the cam timing.

Put the RB25 cams back in the car, take the car to a competent tuner who KNOWS what he is doing, get him to set your cam timing AND ignition timing and RETUNE the car and expect another 50rwkw+.

If there are no competent tuners where you are, then you still need to see one to fix the issue on your car, DO NOT put it in the too hard basket unless you don't want your extra power.

I had a issue like this years back, after fixing the cam timing I gained 80rwkw, seriously the last run was 300rwkw, it went directly up to 370 run to run.

That is all, ship the car to Trent at Status tuning in melbourne, he will sort it out and ship it back to you.

[R32Abuser]

Guilt-toy:

I agree with you. Once I had thought about it all, camshafts really are definied by their specifications. And looking at the RB30 guide and comparing the RB20DET and RB25DE cams there is not a huge difference between the two cam sets. Hence, since they are so similar, they should make similar power.

The only thing here is that, from what I have been told, these motors are more difficult to get timed "spot on" as a result of the different tensioner arrangement. To me I can't see how it would be such a big issue. Either the piston is at TDC or its not. The camshafts should be in the correct position accordingly. I have never timed a motor, so feel free to share your experience!

[GTSBoy]

The only thing here is that, from what I have been told, these motors are more difficult to get timed "spot on" as a result of the different tensioner arrangement. To me I can't see how it would be such a big issue. Either the piston is at TDC or its not. The camshafts should be in the correct position accordingly. I have never timed a motor, so feel free to share your experience!

It can only come from people who do not know how to use a dial guage. How else are you going to set cams when you can't trust the timing marks. Anyone who is serious about this will only do it with the cam covers off.

[Guilt-Toy]

Guilt-toy:

I agree with you. Once I had thought about it all, camshafts really are definied by their specifications. And looking at the RB30 guide and comparing the RB20DET and RB25DE cams there is not a huge difference between the two cam sets. Hence, since they are so similar, they should make similar power.

The only thing here is that, from what I have been told, these motors are more difficult to get timed "spot on" as a result of the different tensioner arrangement. To me I can't see how it would be such a big issue. Either the piston is at TDC or its not. The camshafts should be in the correct position accordingly. I have never timed a motor, so feel free to share your experience!

Sorry to break it to you man, but they are very very hard to get right, even if it looks right its not, if it looks "close enough" then its definatly going to be out.

my experience caused me months of headaches. once i narrowed it down to the cam timing then it took me a month or so to get it right.

You need someone who has been through this issue on the RB30DET so he knows it, been there and done it before. otherwise they usually say "its good, its close enough, she'll be right mate" "can i have my money now?"

My opinion is learn how to do it yourself, you need to take the radiator out, the whole front covers of the engine and that means removing the pulley as well, get a decent puller and make sure the puller does NOT pull from the air conditioning cog, after you look at the engine you can see that the bottom mark is perfect, the intake is perfect but the exhaust is just a little bit out.

try different things, turn the motor over 10 times before checking the timing again before putting it back together, its going to be a long haul but if you put your mind to it eventually you will "fluke" the sweet spot and watch your engine come alive.

I just removed the front covers and the cams on my car to upgrade cams, so i am going to go through the whole thing again. lets hope my dirty thirty goes easy on me this time.

good luck with it.

[lilcrash]

Sorry to off topic, are rb motors interference? I just know that in a previous 3tgte I had someone had bent 6 valves by putting the cam timing 12 degrees out. Wrong timing mark

[The Mafia]

And use an iPhone or camera to take pictures of the timing mark on the harmonic balancer to mark sure that f**king dot is spot on.

You can't get your head in there.

Either that or move the aircon condenser up so you can look straight through. You can move I without disconnecting it.

[R32Abuser]

Timing has been done using the standard timing marks.

Timing will be re-done using dial guages and whilst I'm at it Tomei Poncams (256deg/8.5mm IN&EX) will be put in.

Fingers crossed!

[Bl4cK32]

Timing has been done using the standard timing marks.

Timing will be re-done using dial guages and whilst I'm at it Tomei Poncams (256deg/8.5mm IN&EX) will be put in.

If the builder set the timing and had issues to start with, then re-did the timing already when you swapped the cams over, then 3rd time might not make a difference. Sounds like hes learning and your paying for it.

Im a broken record, but take the car back already No one would blame you if you did and went got it sorted by Shaun who has worked with Cubes and I when we were building these things in '04.

/ill stop pointing fingers now lol