Cam Recommendation

[zartroom]

Hello SAU, been a long time lurker and decided I will taint my record with a thread like this.

Currently running a S2 RB25, Greddy IM, Precision 6062. Made 496whp at 20psi and I am wondering if pon cams would suit my setup. I am planning on going E85 soon and as I am doing my timing belt maintenance now, I thought what better time to go for cams than now? I wanted to gather some information from anyone else with a similar setup. 

[Dale FZ1]

Biggest question is what do you want to achieve?

Throw up a dyno sheet and explain how the car drives (as in engine performance), what you like, what you don't like about it.

 

[zartroom]

Proven low reading dyno here in Tampa Fl, hence the discrepancy. If I could get the power to come on earlier that really would be my goal. E85 will get the extra punch out of it but I am looking for a wider power band. Boost leak tested, turbo bolts are snugged up, manifold to head bolts snugged up. That dyno day my injector seals blew out and we didn't notice theem, as well as running an electronic boost controller that caused some unpleasant wastegate fluttering. full boost hits at 5k-5.5k rpm all the way to redline. Since then I've swapped out the seals, and switched to a mbc and turbo does not feel as lazy, but power still comes on late in my opinion. Haven't seen many running this turbo as I would love to compare the differences.

[GTSBoy]

No aftermarket (larger) cam is going to bring your boost on earlier.

Any longer duration will only move the power curve to the right.

You can of course change the opening and closing event timing by a few degrees with adjustable cam gears. You could do this on stock cams to try to reduce overlap and move the curve to the left a little.

Increased cam lift is "free" power and can improve boost response by getting more gas flowing at lower revs. But more lift is seldom available without more duration. So it's nearly impossible to tease apart the response benefit from increased lift on a Poncam from the penalty from increased duration. And these are usually installed with gears, so it gets further muddled.

Poncams are far and away not the best choice for baby cams. There are a couple of Australian and NZ cam manufacturers who do more interesting cams, combining modest increases in duration with the largest lift that can still "drop in", or even better, with lift that requires clearance machining of the head.

[KiwiRS4T]

What kind of ECU do you have? What's an MBC? If its a manual boost controller you would be better to change it for a Mac valve and use your ECU for better boost control in each gear (supposing your ECU supports that).

[zartroom]

Gotcha. The more I look into it, it seems like my car is performing as it should. videos of others running a .82 ar on a 25 all seem to be hitting full boost around 5k. I guess I could've gone with a .63 and had full boost in 3.5k rpm but who wants a car that can only do 500hp? More boost and e85 is the way to go I guess. Thanks for the advice 

[zartroom]

4 minutes ago, KiwiRS4T said:

What kind of ECU do you have? What's an MBC? If its a manual boost controller you would be better to change it for a Mac valve and use your ECU for better boost control in each gear (supposing your ECU supports that).

Currently running a RS Enthalpy Z32 chipped ecu. Boost by gear or boost by tps would be awesome if I go aftermarket engine management. Car is loads of fun as it is... after e85 will be the point I'll have run out of things to do that don't involve engine overhaul

[KiwiRS4T]

Here's a guy running a 6062 (on E85) making 700hp

https://www.sau.com.au/forums/topic/313603-precision-billet-turbos/page/140/

Scroll down to R33 Ryan on p 140 of the Precision thread

[zartroom]

15 hours ago, KiwiRS4T said:

Here's a guy running a 6062 (on E85) making 700hp

https://www.sau.com.au/forums/topic/313603-precision-billet-turbos/page/140/

Scroll down to R33 Ryan on p 140 of the Precision thread

Seen it as well, someone on that thread seems to be having/had the same issue. running moderate boost (17-21psi) and it only kicks on at 5.5k rpm. Boost leak tested it again as well as ran it with a smoke machine and still can't find anything. 

[KiwiRS4T]

I think the money you would spend on cams would be better spent on a Link or  a Haltech so that you can better control boost build.  Also a lot is in the tune. Most tuners work on the basis that customers want to see as high as possible maximum power figure (which is too often the case). If you get a better ECU and tell your tuner what you want to achieve I think you will have better success. 

[Dose Pipe Sutututu]

  

38 minutes ago, KiwiRS4T said:

I think the money you would spend on cams would be better spent on a Link or  a Haltech so that you can better control boost build.  Also a lot is in the tune. Most tuners work on the basis that customers want to see as high as possible maximum power figure (which is too often the case). If you get a better ECU and tell your tuner what you want to achieve I think you will have better success. 

Nistune Boost control is actually very good, you have the option of a 3D table.

 

wow.. a RB25 coming on at 5~5.5k with only 500hp rear is pretty terrible.

Question around your manifold setup, is it divided or open? Please post up a photo of your hotside. Also cams won't bring on your boost any sooner, I would look at seeing if your VCT is working, without that you're already sacrificing 500~600rpm of spool time.

(bragging rights) I was doing 499hp at the rear on a Mainline dyno with semi-slick tyres. Hit 1.65bar by 4100rpm.

[zartroom]

4 hours ago, Dose Pipe Sutututu said:

  

Nistune Boost control is actually very good, you have the option of a 3D table.

 

wow.. a RB25 coming on at 5~5.5k with only 500hp rear is pretty terrible.

Question around your manifold setup, is it divided or open? Please post up a photo of your hotside. Also cams won't bring on your boost any sooner, I would look at seeing if your VCT is working, without that you're already sacrificing 500~600rpm of spool time.

(bragging rights) I was doing 499hp at the rear on a Mainline dyno with semi-slick tyres. Hit 1.65bar by 4100rpm.

It for sure is absolutely terrible. the flex of 4100rpm full boost is solid my goal is by 4500rpm. As for the hot side I am running the thick cx racing manifold with a precision external wastegate 16psi spring. 3inch downpipe to a resonator and then the muffler. Wastegate is just a 5 inch pipe to atmo. Here's my new theory everybody else feel free to chime in. If my wastegate isn't bolted in as tight as it can be, therefore the fire ring isn't compressed flat on the flange... That could definitely cause some slow spooling issues no? Tomorrow im going to grind down a hex key just for it and crank em down see if anything changes. If this doesn't work then I really am lost. 

[Dose Pipe Sutututu]

3 minutes ago, zartroom said:

If my wastegate isn't bolted in as tight as it can be, therefore the fire ring isn't compressed flat on the flange... That could definitely cause some slow spooling issues no?

100% that would be an issue, if that ring isn't flat you're diverting that exhaust energy from the turbo.

[zartroom]

10 minutes ago, Dose Pipe Sutututu said:

100% that would be an issue, if that ring isn't flat you're diverting that exhaust energy from the turbo.

Will update tomorrow. Just tested VCT, clutch in + in gear, solenoid clicks as it should. Also car drives normally out of boost. I almost miss the days when everything was stock

[Dose Pipe Sutututu]

lol... I wish I could turn back time, I would have just strip sold my R33 land boat when the motor exploded and I would have bought a F30 335i or 340i BMW.

[joshuaho96]

23 hours ago, Dose Pipe Sutututu said:

lol... I wish I could turn back time, I would have just strip sold my R33 land boat when the motor exploded and I would have bought a F30 335i or 340i BMW.

if it's any consolation the F30 has pretty numb steering.

[admS15]

On 29/05/2020 at 2:39 PM, zartroom said:

Will update tomorrow. Just tested VCT, clutch in + in gear, solenoid clicks as it should. Also car drives normally out of boost. I almost miss the days when everything was stock

Nice chairs?

[zartroom]

Long awaited update im sure!!!! f**kin sadly boost leak tested some more, ran it with the smoke machine, and checked torque on exhaust manifold to head, manifold to turbo, and intake manifold to head just to be an asshole and I can't seem to find the cause of the slow spool. Wastegate isn't leaking as far as I can tell. Every time I boost leak test it there is a hissing coming from the q45 tb. If I open the throttle the hissing goes away. Injector seals are fresh so not those either. Chairs are pretty nice thank you 

[joshuaho96]

Set your rev limit to 5000 RPM and a hard fuel cut at 22 psi, find a way to get max pressure on the wastegate spring to keep it closed. If response is any better then you might need to dial in the boost control. Also I hope your wastegate spring is strong, like at least 12-15 psi. Otherwise I think the problem is just your turbo is mismatched to the engine.

[Dose Pipe Sutututu]

1 hour ago, joshuaho96 said:

Set your rev limit to 5000 RPM and a hard fuel cut at 22 psi, find a way to get max pressure on the wastegate spring to keep it closed. If response is any better then you might need to dial in the boost control. Also I hope your wastegate spring is strong, like at least 12-15 psi. Otherwise I think the problem is just your turbo is mismatched to the engine.

That's terrible advice, get it on a dyno and load hold it at a fixed RPM or road speed.