Massive Power Loss

[Kev32gts4]

I just had new camtech stage 1 cams 256 deg installed in my rb20 and it went from 190rwkw to 138rwkw

please help my tuner has no idea why? he has check the tune and time several times.

gt3540r, fmic, 1.2mm metal head gasket, plazmaman plenum, adj cam gears, sard fuel rail, regulator and 280l/h pump

not sure bout injectors but there not stock, apexi power fc, etc

[Simon-S14]

why such a large turbo??

[Crans]

Cam timing is probably incorrect/cam installed wrong. All tho i have heard many stories of cams making the rb20 go backwards

[Dale FZ1]

Both appropriate responses so far, but specs are still a bit sketchy including perhaps an overlay of before/after.

With that turbo (unknown turbine A/R?), and those cams (exact spec not really known?), and comments over the years from Roy about his RB20 exploits, you'd have to be thinking it wouldn't peak - with proper setup on everything - until somewhere well over 8000rpm. So besides seting cam timing, how fast was the engine spun during tuning?

I recall a couple of lads fitting a GT3582 sourced off an XR6T, onto a stock RB20. Pulled maximum power around 9000rpm, but I have no idea how long it ran like that...

[DVS JEZ]

i think in the op it already had the turbo on it, he just installed camtech cams and it lost power.

the obvious things to check, cam timing and if you put cam gears on it, try adjusting these,

check compression may also show if the cam timing is out of wack

[Kev32gts4]

The turbo was on the car when i purchased it and i think the A/R is .82

it had alot of lag before the cams where installed but it is even worse now.

it was running about 17psi at 190rwkw and is now 16psi at 138rwkw

my tuner recons he checked the cam timing and he adjusted the cam gears a few times

just to be sure.

[DVS JEZ]

so your cams failed, put the stock ones back in

[STATUS]

Used alot of cammtech cams with no issues, in fact have never gone backwards once.

Your car has another issue, if it was making 190 rwkw @ 17psi with a GT3540R 0.82 before you changed cams it was already missing 80-100rwkw...... you could nearly make 190rwkw on a rb20 with a r34 std turbo....

you need to find the source.

[TiTAN]

17 psi with a GT35 and only 190kw?

[Crans]

Oh didnt even catch that part. Yeah your car had big problems before the cam install

[STATUS]

i would throw a spare CAS on there, i have had 3 or 4 cars in the 10 odd years ive been screwing with nissans do the same weird thing, car runs perfect yet wont make power, swap out CAS and bang it makes 150 rwkw more. Doesnt make sense but it does happen ask ABU on here .

[Kev32gts4]

Iv been told that it should of been making more power just couldnt figure out why.

i will try swapin the CAS and see what happens

cheerz ill let u no how it goes

[DVS JEZ]

the CAS would of been a prick to diagnose, how did you work that one out Trent?

[Kev32gts4]

I have spoken to my tuner about the CAS and he recons there is nothing wrong with it

he said he checked that it matched up with the what the power fc was telling him.

[paulr33]

whatever is wrong its going to be something simple

to affect the power that drastic its going to be something simple

CAS mangled or unstable sounds bang on the money

ie at idle it checks out ok, but under load it might go spazzo

there were some cheap ebay cam gears going around with poor bolts

do u happen to have a cheap cam gear on it, have you checked the bolts

slipping gears would make it run like ass which is what you see on power

[Kev32gts4]

If it was the CAS would it still seem ok when it was tuned cause my tuner said it matches up

with what the power fc was reading. I have OS giken cam gears

[Guilt-Toy]

When a tuner like Trent offers you some advice like this I suggest you take it on board and actually try it. Do not know who your tuner is but you cannot argue with experience. If he thinks there is alot of missing power I am sure he would be willing to look outside the box... Right?

Ask your tuner to re-check your ignition timing... and when he is doing it take notice if he actually takes the "Nissan" coil pack cover off the engine or not...

Report back with the results, Please. If not.. Take it to Yavus at Unigroup Engineering. Problem solved.

I have spoken to my tuner about the CAS and he recons there is nothing wrong with it

he said he checked that it matched up with the what the power fc was telling him.

[DVS JEZ]

If it was the CAS would it still seem ok when it was tuned cause my tuner said it matches up

with what the power fc was reading. I have OS giken cam gears

Like Trent said. He has experienced carsrunnin fine but low on power and a simle swap of the crank angle sensor has gained alot of power

[STATUS]

would not believe it i actually have an SAU'ers car on the dyno as we speak (rb20 in a cefiro) doing the same thing.

I will post up dyno graphs later. This has the CAS weirdness too. Car hits 190rwkw and nose dives back down....

Replaced CAS pulled 220rwkw on the first run with new CAS.

The only way to check it 100% is to actually strobe the ignition on the dyno (unsafe unless you know exactly what your doing)

Best bet is to swap out the cas with a known good one whilst on the dyno.

This car drove like normal, no stutters... no weirdness at all.... only felt weak up top.

[Adriano]

Could also be valve springs?