Rolls

he only has the intake instead, bummer. Anyone else got an rb25det exhaust cam they are looking to get rid of?

sweet cheers

I need an rb25det exhaust cam, I'm assuming they are different but thought I'd check anyway.

champion, Ill find out if they are the same edit: they are I'll send you a PM

R33 RB25DET exhaust cam, DE possibly will also do if it is the same grind and fit (Im not sure).

no reason to suspect overheating, plenty of coolant and I don't thrash it in hot weather.

We will stick a boroscope in there as well, but it takes 15 minutes to change the cam and it takes what 5+ hours to remove the head then gotta do gaskets and all the old hoses that will no doubt snap. I have nothing to lose by putting another cam in and compression testing, takes no time at all, I don't want to pull the head off and find it is all ok in there, and if I pull the head off and its stuffed I need to get another motor anyway. lysdexia over on the 31 forums said he snapped a cam in a 25 and got off with no bent valves or pistons some how, turned it over hundreds of times as well, cause if the cam snaps wont all the springs try and close all the valves and just put the cam in the position with them all as closed as possible?

r32 with a rb25det

Could a seized lifter also cause the cam to snap? Been speaking to a few people and a mate whos rebuilt 30+ motors reckons he has seen it all the time where if someone rebuilds a head and puts the lifters back in out of order etc it can happen. I have a spare cam so might take all the lifters out, see what the deal is, then compression test it with the other cam, who knows might be lucky and all the valves are sealing, only take 10 minutes to try vs taking the head off, nothing to lose by trying it. Be easier to take the whole engine out than to take the head off.

how would over tensioning the timing belt cause this?

Cranked like a normal engine as the valves are all shut so it would have had compression even if we tested it. Belt is fine, tight as f**k and absolutely no way it has slipped. Doesn't look like an oil supply issue either as there was plenty of oil and the two bearings I checked (next to the snap) look brand new.

where are these nozzles and is it something all turbos normally have or is this something common purely to yours?

?

http://www.skylinesaustralia.com/forums/topic/354952-car-stalled-and-wont-start-turns-over-has-spark-and-fuel-ideas/ So my car snapped its exhaust cam but appears to have oil and the bearings look fine, what are possible causes for this?

stock cam, rebuilt engine and head about 10,000kms ago with forgies and all the usual shit, $7.5k build, luckily I didn't pay a cent and got it with the car for only $11.5k

snapped exhaust cam at cyl 1, all valves would have hit and been closed, pistons could be fine, but its likely they are all lunched. will pull the head off and inspect, might be able to get away with just a new head, but expecting worst case scenario, bare engine is around $1-1.2k so not that expensive. Oh well, thanks for all the advice everyone, will take pics if theres anything interesting to show when we pull the head off. Anyone know how on earth the cam could snap like that? There was bugger all oil in there but bearing caps all look perfect, no discolouration or marks.

possibly, it is probably more down to the afr/ignition not being changed though.

i actually lold reading that

what does 3 nozzled mean/refer to?

rb20 turbo highflowed with BB catridge on an rb25det motor with VCT

I don't get the point of limiting boost, they are tiny turbos so your airflow and power is not massive, as long as you keep the tune rich so the temps are down there should be no real issue even on a stock motor. 18psi on a small turbo = 12-15psi on a larger one, for a given torque figure the actual combustion pressures are always similar, the only difference is 18psi on a smaller turbo is going to mean a hotter intake charge as its at its limit of efficiency, also higher backpressure but with proper tuning this is not an issue.

I have a dyno of mine I can show you, its almost certainly done on a long time duration to inflate the response but it is on full boost (18psi) )by about 2700rpm and power starts to dip over by 6k, mainly due to boost dropping back down to 15, but I'm quite sure the compressor is out of flow by then. In lower gears a more realistic rpm for full boost is about 3200 I would say, drives like a stock turbo but makes 236kw around high 5000 early 6000rpm. thats my best approximation of rpm from the dyno sheet, was in kph, worked out the torque figures from the power and rpm so they might be wrong but the shape is correct, dont have a scanner unfortunately, might be able to get a shot from my webcam if anyone wants it. I think if you can make a turbo this responsive there would be big demand hypergear, this was just made from an rb20 turbo as well with the smaller rear housing.

What actually gets damaged? Ive actually found that the steering lock is still functional, it just has a bit of slack in it now, but it has obviously broken off in the ignition somewhere. Which is weird because it certainly didn't engage when I first discovered it had been broken into.

I actually already have an alarm and central remote locking however the remote broke and the company that made it went into recievership, I pulled it apart looking for lose connections, dry joints etc but couldn't fix it so had to disable the alarm. Hilariously I just pulled the fuse out of the alarm module and it completely bypassed it, so a new one is definitely on the cards once this is all fixed. If it is only $100 to make it use the same key I though might as well do it if the barrel is already out.

the 230kw version looks worse than the 320kw version in every respect, even at 3000rpm it is making 20kw less, comes on full song at 4k like the newer one and then tops out at 230kw, is the main difference the transient response? As I know with my gcg highflowed rb20 turbo it makes ~240kw that feels like a stock turbo, on full song by 3k though it does have a BB core. Is it possible to use the new tech you've used in your 320kw turbo in the smallest sized ones to make say 230-250kw with much better response? or are these benefits entirely due to the different front housing you are using? Also could you explain a bit more about this blow angle you've changed, what is the theory behind what effect it has on the turbo's performance, as from what I can see this is the main thing that has changed and it seems to have resulted in similar response just it holds torque much longer through the rev range and hence power keeps climbing.