StockyMcStock

you need to do this if you have a series one block (as i did!)

exactly my point. the closest point in the setup is the two tensioners, and the belt cannot physically come off the tensioner there. i agree that the belt will flop on the slack side, but it will never touch.

put me down for a pair of RB25 gears in red - must suit series 1 RB25DET. cheers

sweet, i added mine. good work there gents! interesting to see how the old twincharge stocks up against other engines, seems to have the power curve of a standard turbo RB25 but with much higher power everywhere, on less boost. awesome.

there is no way in hell the belts will touch. a number of factory RB engines have it set up with very little clearance between the belts in that area. the belt will NEVER come off the tensioner, think about where the drive force is being pulled from, and the angles involved. the tight side will always stay tight, for obvious reasons. the "slack" side will have more flop in it for sure, but no way in hell is it ever going to physically come off the outside tensioner. i see no real reason to put the tensioner up higher, other than the fact that it looks better and the belt wrap on the inlet cam is slightly better. looking at a stock supra engine the other day convinced me that you only need 7-8 teeth in contact anyway.

for the money you'll spend, you could pull the 25 head off, port it heavily and fit bigger stainless valves, put a solid lifter conversion into it and buy some new cams. this is all similar to stuff you would do to the 26 head before you put it on anyway (rebuild it, port it, maybe fit bigger valves, buy big solid lifter cams etc) so you will come out at about the same price, with no dicking around with custom injector rails, loom changes, ECU changes, manifold changes etc. so my advice, if you really feel you can't get any more power out of it in current configuration (which you sure can!) would be to pull the head off and work it heavily, fit a solid lifter conversion and bigger cams. this will enable you to raise the rev limit, and hence powerband. you could fit a slightly larger rear housing to the turbo too. i just can't see it being cost effective (in your situation) to change everything to the 26 head. if you were starting from scratch, it would be a different story altogether. cheers mike

nissan put them there just to be c**ts, they really have no purpose.

pictures aren't quite big enough, i can't make anything out while you probably already know that open collector + split pulse housing is a bad idea from a gas flow perspective, it's a really super bad idea if your turbo-manifold gasket is split pulse as well. it can break off in the centre section and go through the turbine, not a good thing. make sure you trim it down (cut the divider out) if this is the case. it won't be optimal, but it'll do the job. cheers

ummm...... nowhere? it spins the tyres everywhere in first and 2nd, and i haven't done above 5500rpm in third really. it's hard to tell if the powerband drops anywhere, it certain doesn't feel like it?

So where does my dyno graph fit into all this?

the rear is far too small. your massive exhaust back pressure, coupled with a high compression motor is forcing you to run low timing otherwise it will ping. realistically, you could step that up two sizes (rear housing) and end up with maybe 500rpm more of spool time, but a much better motor. otherwise good luck.

yeah, i was thinking it would be okay for 350kw if i kept it under 6800, accounting for the difference between dynos etc. 350 is like 600 engine hp, that would be pretty nice. still don't think it'll reach the limits of the compressor(s) but it would sure go pretty well. would have to be the most responsive 600hp 3 litre engine i can imagine. might be able to have a crack at the 5 speed VL turbo record too with that power. wouldn't have any lag so you could probably get good 60ft times to get the ET down. hmmmm.......

you should do that first, as it might change your dump pipe flange. also it will make more power with the open rear, as you have an open collector. maybe i'm just anal but i would do it asap. dry sump looks good mike, you have waaaay too much money to throw at that thing! p.s. one day in your off-season, we should pull all the gear off the hotside of my engine and bolt it to yours, then get it tuned. i'd be keen to see just how much power it can make. my rods will let go if i push it anywhere near its limits

interesting - lucky i won't have to bother grinding with the 264 though. going to get an adjustable wheel at the same time and try and dial them in with a degree plate/dial guage properly. throw it back on the same dyno and see what it does. don't worry cubes i'll post dyno sheets. my guess is 410rwhp on 15psi, but that's just a guess.

excellent, i'll go the 264 then. cheers mate!

okay so the 264 with 9mm of lift will go straight in without grinding the cam tunnel edges? the rest of the head is identicle to a DET head.

So i have an R33 RB25DE series 1 head on my 25/30 right, and i want to stick a big exhaust cam in it. I understand that above a certain amount of lift, you need to grind off a bit of the head so that the lobe tip clears as it swings around. i really don't want to disassemble the engine, so i was hoping to avoid modifying the tunnel if i could help it. Question is, how big can i go on the cam before i require grinding? I want either the HKS 256 duration, 8.8mm lift or the HKS 264 duration, 9mm lift. Cheers, Stocky

Hey michael, thanks for lettin me have a squiz at the racecar, top piece of work there. MAKE SURE YOU ASK ABOUT THE OPEN-COLLECTOR, SPLIT PULSE HOUSING DILEMMA! i want you to make an informed decision on the thing before putting it on your engine. it's an expensive piece of equipment, that new turbo. see what the experts have to say about it. at the very least, it won't be optimal for gas acceleration and turbulence through the housing. at the worst, it could melt your scroll separator bar and put bits of molten metal through the turbine wheel. just something to think about definately need to take you for a ride in the dry, you can't really appreciate a twincharge otherwise don't worry it'll be tuned for 300kw soon, that will be more fun i promise. not quite as spastic as your racecar though..... platinum - standard plugs are fine man. i use and recommend Cheap Shit Plugs®, they are doing fine so far. edit: because i'm anal, i collected some quotes for ya: okay so i can't find any more cause i suck at the internet. just ask around and see what the "experts" say.

strictly for nissans? i've been a regular here for a while now but i drive a nissan-powered commodore will i get in trouble if i come?

disregard that post i just realised you're in tasmania, you filthy three-eyed hillbilly* *exaggerations

that's some good gear there man, whereabouts are you? if you can find wiring diagrams for either of the alarms i might buy one off you. also that helmet would be sweet but need to know where you are.

i had a Q45 AFM explode on me (long story) and i couldn't start the car. after picking up the pieces of the AFM casing i had to get a tow home was hoping i could limp it back but no go.

save yourself $1500 and don't buy the HKS turbo. get a genuine garrett GT30 or GT35. that 1500 bucks can be better spent elsewhere. i have no idea why people pay twice the money for a VERY similar turbo just because it has a japanese brand name on it?

i did 2000km on mine before getting it tuned, it was an RB30DET with a GT40 turbo though. it was running massively fat across the top end which i think saved it from pinging. it also mad a lot less chance of detonation due to the very free-flowing hotside so you might not be as safe on a stockish RB25DET. mine did amazingly well on the base map, even getting 400km to a tank of fuel. did 570km on a tank once when driving to bundaberg which i thought was pretty good. got it tuned now and it was immediately much better. if you're in brisbane i can recommend john at mercury motorsports, he did a ripper of a job in a very short time for me.

yeah it starts spinning 1st gear at about 3500rpm if you keep your foot down, then 2nd it will turn them again when you hit full boost shift too quickly like i did in the video and it's all over as far as the tyres are concerned. i'd love to do this to an RB25 to show you guys how easy it is to make huge power out of a twincharge. it would really transform a 2.5 litre engine that's for sure. even better would be a GTR that could cope with the power. the 3 litre bottom end helps a bit, but when you have boost delivery like i have it's not really necessary.