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R33 Skyline Gtst Turbo Cams Issues

Turbz RB-25

By Turbz RB-25,
in Engines & Forced Induction

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Turbz RB-25 Experienced

Turbz RB-25

Posted
Posted

Hi guys, I got my poncams installed today with 260 on the exhaust and 256 on the inlet with type-a valve springs.

I have a HKS GT2835 Pro S turbo, front mount, exhaust, all the other usual mods, injectors, fuel pump, Power FC etc. Before I got my cams installed I had a healthy 272 rwkw.

Today, with the cams installed I only got 258 rwkw!! Not only that, the boost came on later!

Now, the mechanic (I won't mention who it is) told me that before he was running 18 degrees of ignition timing, now it's running at 14.

Also, from the boost curve, he said that my boost controller, which is a turbo tech one, can't hold the new air flow the cams make, that's why there is a big drop in boost!

Frankly I am !ssed off as I spent $3,000 getting the cams and getting them installed, all to get less power with more lag, wtf!

Mechanic said I must have bad fuel in the car, because if he tried to run it at 18 degrees, he said it was pinging like crazy.

People, I need your help, and opinions as to what the F#%k is going on, and what I can do to fix it!

ALl the mechanic said was to use BP ultimate and get a apexi power fc boost controller next time for the tune and it should be fine, what do you guys think??!!!!!!

I attached the picture of the dyno before and after, please have a look and tell me what'sgoing on!

post-48356-1229073439_thumb.jpg

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https://www.sau.com.au/forums/topic/248691-r33-skyline-gtst-turbo-cams-issues/
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discopotato03 Grand Master

discopotato03

Posted
Posted

I was under the impression that Tomei Pon Cams for hydraulic RB25's (R33) were 256 deg duration inlet and exhaust .

I had though the R34 versions were 252 and a tad more lift than the R33 hydraulic ones .

You may want to double check the boxes because there was recently a mix up between inlet and exhaust cams and almost R33 and R34 types .

No names but check all the part numbers .

A .

PM-R33 Grand Master

PM-R33

Posted
Posted

Sounds like a very similar problem i had man, but with my old HKS cams.

http://www.skylinesaustralia.com/forums/Di...+Valve++springs

No matter what we did we couldn't figure out what was going on. Ended up selling the cams, ripping the head off to check everything and now rebuilding the entire head with new cams.

What cam are you using on the exhaust side to get 260 degrees?

Turbz RB-25 Experienced

Turbz RB-25

Posted
  • Author
Posted
I was under the impression that Tomei Pon Cams for hydraulic RB25's (R33) were 256 deg duration inlet and exhaust .

I had though the R34 versions were 252 and a tad more lift than the R33 hydraulic ones .

You may want to double check the boxes because there was recently a mix up between inlet and exhaust cams and almost R33 and R34 types .

No names but check all the part numbers .

A .

THe inlet was a poncam 256, and exhaust was PROcam 260.

What you're saying that he could've put the 260 on the inlet side and 256 on the outet?

PM-R33 Grand Master

PM-R33

Posted
Posted

Nah that aint possible to do, the cam gears won't go on the wrong cams. But yeah running the procam on the exhaust side is a bit questionable. I thought the procams were only for solid lifters?

tridentt150v Grand Master

tridentt150v

Posted
Posted

Check to see if they are on zero, all the cams I know of are already dialed in for a zero setting. Set them to zero and have a drive - you'll need a retune as well. I did the same thing with mine, and the tuner was more used to GTR tuning so wasn't aware that you set to zero for Gtst's. I went from 245rwkw without cams to 215rwkw with cams....bummer.

I reset them myself and the power difference was huge and very very pleasing. Got a tune later and 257rwkw.

MBS206 Grand Master

MBS206

Posted
Posted

You don't just set the cams to Zero degrees.

They NEED to be dialled in properly.

Also, running different sizes from inlet to exhaust does different things with the engine.

You will most definitely HAVE to dial them in to make the most of it, and this is why your power will be out and your ignition timing.

joeyjoejoejuniorshabadoo Grand Master

joeyjoejoejuniorshabadoo

Posted
Posted

poncams on an rb will bring up your top end BUT will delay your boost threshold a few hundred rpm.

eg. my mate and i have the exact same setup, same tuner, same dyno... mine without cams, his with

i make 265rwkw with full boost by just under 3.5k

he makes 275 rwkw with full boost by just under 4k

(OO)Firty Free(OO) Rising Star

(OO)Firty Free(OO)

Posted
Posted
Could bad fuel really cause the tuner to have to turn down the ignition timing from 18 to 14? (98 ron stuff).

Could the cams them selves be making the car ping?

I run BP Ultimate and my top end map is running between 12-14 ignition timing any more and it would detonate. I think you will find most PFC maps with skylines running decent boost will be very similar,I'm running 18psi with a 3037.

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