Cubes

I picked up the vg30det turbo for $300 or was it $350.. It was some time ago. I wouldn't put a VG30 turbo on a RB20DET, I've done it in the past and it was a bad match. The turbine housing is too large for the little compressor. A RB25 turbo is a much better match to the RB20DET, it has a slightly larger compressor wheel than the vg30det turbo and a slightly smaller turbine housing. On small motors you want to keep the turbine housing as small as you can. The VG30det turbo will make the same power as the rb25 turbo BUT there will be less area under the curve on a small motor. The RB25 turbo vs the vg30det turbo on a RB30DET, the vg30det will have more area under the curve as the motor will rev harder and not flatten out at the top end. as much.

The rb30det is in an R32 so the boost control method in those is basic. They simply run a line from the comp cover to the actuator, you place the boost controller in the middle. My problem is the turbo is too small for the motor, it makes its peak power at 4400rpm! I'm bolting a cheap Vg30 on now to keep me happy until I bolt the xr6 turbo on around xmas.

I am now had issues with this. I noticed a few changes to the way the car started first thing in the morning. First thing in the morning when cold she would start, stumble then want to stall, most of the time it would stall. Especially if I touched the accelerator to try and bring rev's up. Start her again and it would idle fine, HOWEVER if I were to touch the accelerator to try and give her a little free rev she would stumble and try to stall. Knock levels have also gone up, it never used to knock now it tends to knock when coming off the throttle (looking at the pfc h/c graph) and changing gears after wot half way through the rev range. It doesn't so much hold a knock it only spikes a knock.

The turbotech boost controller definitely tails off with my rb20det turbo. HOWEVER, the rb20det turbo in its tailing off state (12 down to 9) is making 176rwkw. The turbo has reached its power limit. I can adjust my actuator all the way out and the stock turbo will make 1bar+ in the mid range but as soon as peak power approaches boost will ALWAYS tail off to 9psi no matter what. Prior, the rb20det and the same stock rb20det turbo was able to hold 1bar using the adjustable actuator, yet only made 165rwkw. I didn't have the turbotech at this time to test unfortunately. There is nothing I can do to get this rb20det turbo on the rb30det to hold boost. A friend put it on his VLT, it too dropped boost to ~11psi or so. He ended up breaking his stock actuator fiddling, replaced it with an aftermarket adjustable item. It now holds boost much better but STILL tails off. He suspects its his 2.5" exhaust. 2.5" is too small. I run a 3" with a crappy dump pipe courtesy of a so called 'Performance Specialist' *see advert*. I think the only way to go is 3.5" or 2 x 2.5". The bloke with the VLT did say it was better than his GFB bleeder.

I remember freebaggin made some where up around 270-280rwkw on 17psi with his hybrid turbo using a vlt turbine housing. The turbo specs were selected by Tim Possingham, it was an expensive bugger though, just under 3k. I suspect the comp and or turbine housings had a little bit of power porting. The HKS int. gate housings are around $800.

I had a friend install it on his VL, it would only hold 10-11psi or so, stock boost on those are around 7. I'm putting the turbo on tomorrow with the bleeder, I suspect it will tail off at high rpm as my dump pipe is not the best. I'll be getting a split dump made up when I drop the xr6 turbo on around xmas. I've got a vg30det bb ceramic turbo going on to keep me happy until then. It should only need around 11psi to make ~200rwkw.

Isn't the dump pipe stock but the front pipe aftermarket?!?!

Just under +7 as in just under the line or the actual print +7? If just under the print or .7bar (10.15psi) sounds right. My stock boost with a full 3" is 11psi. Some with a 3.5" have seen 12psi.

Best u can buy. 5" isn't much to worry about unless its sitting 1" off the ground.

What an idiot. Quite unbelievable how he was able to hold the car still and get it to smoke up.

Al, Your origional dyno runs. Were they run in shoot out mode? I bet the dyno day was.

wow.. 3-4secs... Thats too long, a friend of mine's pfc also has a slight delay. Basically by the time you have taken your hand off the key its all powered down.

Which king bearings did you use? The AM or HP? Both are a performance bimetal. The CP trimetals are the usual street family wagon bearings.

I've heard bad reports of using tri-metal style bearings in hipo rb30's from the VL turbo boys, we are talking up over 300rwkw though. An RB is an RB.

Who notices that when you turn the key off the car still runs for half a second or so before powering down? There's a noticable delay, unlike the stock ecu where the motor is killed instantly.

I'm using King bimetal high performance. Fairly well priced as well. The builder was able to get them for cheaper than the nismo items. + he had used king with success in the past. I've done 20,000km's so far.

Damn, the ute looks like a Commodore.

Don't forget the stock injectors.

heheh only in WA.

Its only a suggestion, if you are 100% confident the valve springs have good seat pressure and are not floating under high back pressures then I wouldn't worry about it. The inlet mani is fine, the exhaust is fine and the valve springs are fine. That leaves the fmic and exhaust manifold. I would probably look at trouble shooting in the following order Drill/tap pressure guage in to exh mani or turbo housing. Then consider if the exh. manifold needs replacing if there are extreme back pressures that may also be causeing a little float and reversion. Replace FMIC As I said quite some time ago. The bloke I bought that machined GT35R turbine housing off had it on his stock exh. manifold, he was running 18-19psi with 256duration cams and made 306rwkw. That was the limit. He changed exh. manifolds to a ext. gate setup and on the same boost picked up 20rwkw. How much of the 20rwkw was due to the exhaust manifold is to be debated.

Sky30, I think you don't understand what I mean. If your valve seats are pulled up in the head the stiffer valve springs will make some difference but not completely resolve it. Lifter jacking to the point where it causes the car to miss is the extreme end of valve float, that is being extremely close to smashing valves on the pistons. It may not be the case but its something I would look in to especially after bl4ck32s head being so loose from factory. Its easy to check. I still think its the stock exh. manifold and nothing to do with the above, but its worth a shot. Here's a little tech write up on seat pressure. http://www.cranecams.com/?show=faq&id=5

Got a multimeter? I changed the pics in my prior post.

390rwkw.

matlowth, How was the hotside setup? turbine a/r size and exhaust manifold? I'm a firm believer this is what needs to be done to the 3ltr in order for it to rev.

You can always have the pipe do a 180degree bend and run behind or level with the bottom of the IC. My current IC has in/out positioned in the center of the core.