M35 Engine And Turbo Out

[Sunkist]

How do you snap a blade on the steel fan? low oil feed at idle explains it to me better than a freak blade breakage!

I don't have a clue what GCG have....I lost interest with GCG after they said there baring set for our turbo was only good to about 450HP....GCG say you don't have to do anything to our car....just bolt it up.....IMO that's wrong!....I have heard GCG unit's on other cars and the sound nothing like ours!....which leads me to the assumption that while I am sure GCG can build a very good turbo there thinking is typical of the rest of the numpty suppliers out there that have no idea about the VQ25DET motor!

Without doing an flow test with different restrictors who would know on our car what is the correct restrictor is to go with what combination! I'm just going off the info my turbo guy gave me when he handed me back the new unit!...and the previous result's found from someone else that did a flow test and had the same turbo as me!

lol i thought the same thing, but looking at it, a blade was missing completely.

well with what you said sort of making sense in my untrained head, how does that explain scotts performing well at 20psi regularly with an unchanged banjo.

[Jetwreck]

lol i thought the same thing, but looking at it, a blade was missing completely.

well with what you said sort of making sense in my untrained head, how does that explain scotts performing well at 20psi regularly with an unchanged banjo.

the flow probably is not as big a problem at high boost...don't know without testing!......how do you explain me not popping seal's at far more boost that 23PSI? maybe it's because we have quite a big return system!

....and with Scott's tiny winy turbo he does not need much oil!...lol...."await's flamage and something about 300 from Scott!"...lol

I cannot remember if Andy was told to open up his line...but I opened it up anyway as I had the thought that although his turbo was different in a couple of way's he would need the flow!

Edited February 1, 2011 by Jetwreck

[Sunkist]

the flow probably is not as big a problem at high boost...don't know without testing!......how do you explain me not popping seal's at far more boost that 23PSI? maybe it's because we have quite a big return system!

....and with Scott's tiny winy turbo he does not need much oil!...lol...."await's flamage and something about 300 from Scott!"...lol

I cannot remember if Andy was told to open up his line...but I opened it up anyway as I had the thought that although his turbo was different in a couple of way's he would need the flow!

lol well wouldnt his tiny whiney turbo be spinning faster than yours to fill up the FMIC and plenum? which means he would probably need more oil. just because they're larger/smaller fans doesnt mean the core really changes in its design.

and im pretty sure scott has the sierra stage 1 wheel just like andy..

[Daleo]

lol well wouldnt his tiny whiney turbo be spinning faster than yours to fill up the FMIC and plenum? which means he would probably need more oil. just because they're larger/smaller fans doesnt mean the core really changes in its design.

and im pretty sure scott has the sierra stage 1 wheel just like andy..

The rotational speed of the shaft doesn't dictate oil flow, its not a pump.

However differences in base engine oil pressures would dictate a larger or smaller orifice to provide equal amounts of flow.

Bush bearing turbos work like this;

In the housing there is a machined recess for the shaft bearing.

There is a tiny amount of clearance around the bearing, it is not pressed into the housing (generally they are a whitemetal or whitemetal coated bronze) the impeller shaft passes through the bearing.

There is a tiny amount of clearance to the shaft.

This is called a floating bearing, as the bearing floats on a cushion of oil, and none of these surfaces come into direct contact, as there is always a film of pressurised oil separating them.

Without this floating bearing, the turbo would never be able to sustain rotational speeds up to, and sometimes in excess of 100,000rpm. I used to build & balance Napier turbos with compressor wheels over a foot wide, and would spin to 118,000rpm (tacho input on shaft for dyno tuning)

The only fixed bearing in the turbo core is the thrust bearing. This stops the rotating assembly from coming into contact with the compressor cover. It has radial grooves to feed oil out from the centre of the shaft across the thrust face.

You can see why this would require more oil than a BB core; it's effectively splash lubrication as the oil is only used to wet the balls in a BB core, so the pressure required is virtually nil, whereas the bush core actually needs a pressurised oil supply in the housing to keep everything apart.

Edited February 1, 2011 by Daleo

[scotty nm35]

And yet it is only the BB units with issues so far.

I am more worried about dropping oil pressure in the engine by opening it up. Kip has mentioned "the skyline's do it that way" but RB's have their own oil control issues I don't want any part of. The cost of rebuilding a bush turbo is nothing compared to an engine, right?

I have seen nearly 9 bar (cold) so far on the informeter, generally it runs around 3 to 5 bar on cruise. Is that more than usual?

[Daleo]

And yet it is only the BB units with issues so far.

I am more worried about dropping oil pressure in the engine by opening it up. Kip has mentioned "the skyline's do it that way" but RB's have their own oil control issues I don't want any part of. The cost of rebuilding a bush turbo is nothing compared to an engine, right?

I have seen nearly 9 bar (cold) so far on the informeter, generally it runs around 3 to 5 bar on cruise. Is that more than usual?

I know, it's the opposite of what you'd expect. I don't have an explanation either...

I still think there's probably enough flow in reserve to open up an orifice by 1mm though, there'll have to be a restriction in the core before the oil goes to drain anyway, otherwise you'd never generate any oil pressure in the core. The orifice is just there to ensure you don't feed the core more oil than it can get rid of, thus running it over pressure.

9 bar (130psi) seems quite high, but 3-5 (43.5 - 72.5psi) seems spot on the money at cruise. I guess the deeper you dig with these engines, the more you find. If it was a problem, you'd be blowing seals out all over the place.

Edited February 1, 2011 by Daleo

[Sunkist]

so based on this, 1/8th or 3mm orifice in the bolt will be fine? for a journal bearing?

(Sorry OP for hijacking your thread)

[Tommy Kaira RL]

Got my GCG high flow today after a long wait and got back to work pulling the top of the car off the engine and gearbox again.

So after installing turbo and all the oil and water lines then did it all up. Have a new dump pipe on aswell.

My question is should I turn engine over without starting it a few times to get oil pressure to turbo? Or just crank it. Would there be enough oil on bearings allready for first start up.

Going to finish job tommorrow and take it for a big spin. Just got all the electrics and hoses to connect

P.S Andy I got the banjo in first time on the block. Just bent the lines slightly until it was square.

I had allready bolted turbo on before I called.

[andy65b]

Pleased to hear you got it no problem.

I just started mine but my turbo is journal bearing.

Look forward to hearing the result.

Cheers

Andy

[zei20l]

just kick it over, oil will get up there pretty quickly. im sure it doesnt stay in the turbo all the time, it will drain out after you stop the motor and leave it.

[Tommy Kaira RL]

Finally got it back together last night. The suction pipe would not bolt on the front of turbo in the car. I thought I was going to have to take the turbo off to get to the 6 botls that hold the snail. I could only undo the botoom surrounding 4 bolts. This gave the turbo enough clearance to turn it with a crow bar. Its been one thing after another.

Anyway very happy with overal outcome. The power is slightly increased and its a lot smoother, quieter. It is a tiny bit lagier than stock.

Only thing Ive noticed now when I start the car it makes a small fart sound. I think its the actuator?

[scotty nm35]

How did the dump go mate?

Its a common issue, unfortunately the turbo guys dont clock the housings correctly and the intake wont fit properly. Hopefully the housing is centred or the compressor will rub.

The farting sound could be many things, can you explain where and when it happens? Only on startup?

[Tommy Kaira RL]

It only does it on start up. It dosent even last a second. It sounds like the diaphram in the actuator filling up with air. Its coming from that area.