Is This Turbo Useless

[Driftnuttz]

I am swapping an rb20det into a 240sx (in the USA). Well the motor came with a Rb25 turbo, I think its from a neo. I am pulling the head off to redo some stuff, and while the turbo was still on the motor I flipped the whole motor over on the engine stand. When I flipped it back up right I saw oil coming out of the turbo from both sides. Wen I removed the turbo it had a lot of oil in the exhaust housing. Do you guys think the turbo is junk? I have never seen the turbo in a car running, but it has little( I do mean little) shaft play and spins freely.

[paulr33]

if you are re-doing the head you would be crazy to put an unknown spec age ceramic turbocharger back on it

if you are spending money on the head, then go for a new turbocharger or highflow the std one

the ceramic turbochargers are basically timebombs with age and especially if you start pushing it when a fresh head and want lots of power from it

[GTScotT]

As above. When the factory turbos let go they can take the motor with them, so dont risk your fresh head (or whole motor) on the cheaply replaced standard turbo.

Personally I think a highflow is an awesome option for these cars these days, the technology is definitely there. If you do go something completely custom, dont go too cheap on it. Something genuine or atleast Kinugawa.

GL

[GTSBoy]

Despite what the guys above are saying, the turbo itself is probably fine. If you tip a bunch of oil down the turbo drain while it is inverted and let it sit there in the core, it will leak through the seals and out into the housings. It's just a question of how much how fast. If you're completely paranoid, you will take the above advice and get something new. If you're only partially paranoid, just take it to a turbo workshop and get them to quickly check it out.

For your own benefit, you can tell if it is from an early motor or a late motor by seeing if the compressor wheel is alloy or plastic, plastic being from the later ones. And if it has OP6 on the exhaust housing then it is probably from a Neo, as advertised.

[GTScotT]

Yes he is correct about the seals leaking because the contents of the sump backed up into the turbo...

BUT,

The point here is that its still an old CERAMIC WHEEL turbo which is a time bomb REGARDLESS of this oil situation. We are simply giving you stout advice in an effort to protect you from potentially a total failure when the turbo lets go and takes the motor with it.

Anyway, GL.

[Driftnuttz]

Ok guys thanx for the imput. I was thinking that the seals would let oil through if there was oil just sitting in there.

When I got this motor it was supposed to be a full swap readdy to go in the car. I was shocked to find that it was a full r31 rb20det redtop, and I have had to swap everything aside from the block over to silvertop parts. This has really pushed my budget way over what the wife and I talked about. I would love one of those high flowed units, but here in the states its not a real option. To do that to a turbo it costs almost the same as new greddy unit. I will be upgrading the turbo as soon as the money is there. I am just going to use this turbo to get the motor going. If any of you guys wants to help me out by sending me one of those hig flowed units feel free...lol

I am 90% sure its from a neo. The comp housing has this on it "GARRETT A/R .60 M24 N (in a small raised box 6116) 1" When I googled these numbers they came back as a neo.

[GTScotT]

The front should read 4v54 and the rear OP6 if it is the R34 NEO turbo.

[Driftnuttz]

I will go look and see if it does say it. I have pics but I cant post them up. Here is the comp housing on my facebook, if someone doesnt mind can you post it for me.

http://www.facebook.com/media/set/?set=a.160161667369856.51045.100001280722330#!/photo.php?fbid=190229841029705&set=a.160161667369856.51045.100001280722330&type=1&theater

[Driftnuttz]

Ok so the rear housing does say op6, but the front housing does not say 4v54. Any clue way this is? Think I could have gotten lucky and it is a jdm remanned unit? < I dont think this is the case, but I guess anything can happen. The guy I got it from really had no clue what was in it or on it, other then what he could see. He did claim a lot, but non was true. I am thinking that he bought this from an importer to swap into his car and ran into truble cause it was redtop rb20det.

[jjman]

yeah from my knowledge the very final series of turbo's to go on the RB25 Neos were a Garrett unit instead of the nissan ones that have the 45v4 etc on em.

From what i can gather this means this was prob the best stock turbo to grace an RB25... Also has an alloy compressor wheel, which = Less chance of the compressor wheel falling to bits in going into the intake...

lucky guess- is it this unit in the pic? http://www.skylinesa..._1#entry5622698

also check the bottom of this page.

http://www.skylinesa..._1#entry1279551

Edited July 19, 2011 by jjman

[Driftnuttz]

Yeah man its this one http://www.skylinesa...&attach_id=1595

I wonder how much boost would be safe on a rb20det? I had a older rb25 turbo on my last one and ran 15psi, I didnt drive around at full boost all the time. It would move when I floored it though...lol

I take it they still used the crappy ex wheel, right?

Edited July 19, 2011 by Driftnuttz

[jjman]

yeah, still got that ceramic exhaust wheel...

up to you. Id say keep it below 12psi n work pretty quickly towards getting it highflowed or upgrading.

[Driftnuttz]

yeah, still got that ceramic exhaust wheel...

up to you. Id say keep it below 12psi n work pretty quickly towards getting it highflowed or upgrading.

Why is everyone scared of these turbos on rb20s? I mean I see people saying on rb25dets they should stay below 12psi, why is it the same on a 25% smaller motor? I would think that you could push more boost on a smaller motor, as the reason they fail is because the heat makes the wheel weak and comes apart at higher shaft speeds. 12psi on the 20 would not need the same shaft speed as on the 25, plus the ex would not be as hot at 12psi. Add to that the fact that the head does not flow the same, so the more resistance in the system the less air the turbo needs to move to see 12psi. This means the wastegate is opened more and the ex wheel is seeing less ex gas helping even more to keep the heat off the wheel. Make sence to you?

[Rolls]

Yeah you can run more like 14psi on an rb20 fairly safely, much over 12 on 25s and they seem to destroy themselves, haven't ever heard of it happening on a 20 though, stock 20 turbo yes, but not 25 one.

[Pal]

^ +1.

[jjman]

because most RB25 turbo's have the plastic compressor wheel which can also shit itself pretty easily at the same time the ceramic wheel lets go, hence the big fear. And as this plastic wheel is on the intake side it can suck the plastic bits into the motor n require a rebuild.

Iv got the alloy wheeled S1 turbo n have that bad boy wound up to 15psi (for 1 yr n had it at 12psi for a year before that). No problems at all. Nonetheless, from what i can gather it is still possible (but far far less) to fracture the compressor wheel if the turbo failure is bad enough (shearing the shaft which then means the compressor wheel gets really loose or pops off n does indeed break off bits of the blades on the compressor housing).

As far as how it would spin on a 20 i cant comment. But your arguement sounds reasonable.

Tho it would be a bit rough of us to tell this guy in the states to wind up this turbo 'as you shouldnt have any trouble' only to indeed have it shit itself and do some damage to his motor...

[Rolls]

As far as how it would spin on a 20 i cant comment. But your arguement sounds reasonable.

Tho it would be a bit rough of us to tell this guy in the states to wind up this turbo 'as you shouldnt have any trouble' only to indeed have it shit itself and do some damage to his motor...

Totally agree, he should have it rebuilt with bigger spec steel wheels imo. 15psi is really pushing the efficiency of the turbo, in the midrange it'll make more power, top end I doubt it.

Edited July 20, 2011 by Rolls

[jjman]

btw- just to clarify. while we say we push these turbo's to 'X'psi this doesnt mean it holds this boost right through the rev range. This is just the max boost it made in the midrange. Its commonly known its pretty hard (and otherwise abusive) to get a stock turbo on an RB25 to hold anything above 11.5-12psi to redline as its well out of its efficiency range. Hence why keeping them at 10-12 pis is usally best because its in the relative efficiency range.

Edited July 21, 2011 by jjman

[Driftnuttz]

btw- just to clarify. while we say we push these turbo's to 'X'psi this doesnt mean it holds this boost right through the rev range. This is just the max boost it made in the midrange. Its commonly known its pretty hard (and otherwise abusive) to get a stock turbo on an RB25 to hold anything above 11.5-12psi to redline as its well out of its efficiency range. Hence why keeping them at 10-12 pis is usally best because its in the relative efficiency range.

Yes this may be true, on a rb25det. On a rb20det its not moving the same amount of air at 15psi. My last 240sx(s13) had an rb20 and rb25 turbo and it held 15psi strong till redline all day everyday. When I installed the manual boost control I had it set waaaay too high and it shot up to 18 at the blip of throttle. So if you have problems with yours holding 12 psi on a rb20, I would check to make sure something else is not wrong.

[jjman]

Yes this may be true, on a rb25det. On a rb20det its not moving the same amount of air at 15psi. My last 240sx(s13) had an rb20 and rb25 turbo and it held 15psi strong till redline all day everyday. When I installed the manual boost control I had it set waaaay too high and it shot up to 18 at the blip of throttle. So if you have problems with yours holding 12 psi on a rb20, I would check to make sure something else is not wrong.

ah cheers for that clarification. Ive never known how they run on rb20's. im a 25 man myself and what i illustrated above was on a 25.

sounds like they are happy to flow more psi on the 20 due to the smaller cc's and exhaust flow...

Edited July 21, 2011 by jjman