BB turbos dead after 5000km?

[Terrh]

I bought a pair of garrett GT2871R turbos for my car and put 'em on.

I used the stock banjo bolts (no restrictors) and they worked fine for the first 4000KM. I had to take them off, and when I put them back on I put oil restrictors in. They were fine at that time. Since the restrictors went on I've put maybe 1500-2000KM on it. Recently went on a short (1000km) road trip and had the front turbo crack a coolant line. The car was apart for a few weeks, when I put it back together I noticed the front turbo was noisy, especially after I shut the car off while they were spinning down.

Now the front turbo is absurdly loud and the car doesn't make boost, and smokes any time I give it gas. I haven't taken the turbos off yet but I'm pretty sure the bearings have died in it. I don't hear the rear turbo spin down anymore either. The only thing that I can think of that could have damaged the turbos is lack of oiling from the oil restictors.

Has anyone else had this happen?

[Supraclean]

All aftermarket garret BB turbo require a restrictor. You probably damaged them/ possible where on there way out in the way before you put the restrictors in.

Are you sure the lines were clean an no debris got in?

Refer to Garrett's website regarding bb fittings.

[Supraclean]

http://www.gtr.co.uk/forum/163453-ball-bearing-turbos-too-much-oil-pressure-causing-oil-leak.html

[Terrh]

the #4 post in that thread is making me suspect that restrictors were a bad idea.

My car never pushed oil past the seals in them, I only put the restrictors on because I had read I should be running them on the garrett website, I had the turbos off anyway, and my car makes a lot of oil pressure. Not sure how much, but at high RPM my gauge is pegged at 100PSI, and cruising at 2500rpm it's usually above 70, measured after the filter.

I've got an old pair of HKS 2510's (another garrett BB turbo, similar to a 2860 but a bit smaller) that I'm going to put on the car for now, they were on another GTR and I looked in the hardlines on them, no restrictors either.

[Skym]

Non ballbearing CHRA requires more oil and usually have to drill stock restrictors out (hybrid stock turbo). Ballbearing CHRA requires less oil.

Probably wrong size restrictor or is non ballbearing CHRA. There's many different size restrictors, depending on turbo you are fitting (I think it was the larger turbo's have bigger oil ways inside CHRA).

[Terrh]

Non ballbearing CHRA requires more oil and usually have to drill stock restrictors out (hybrid stock turbo). Ballbearing CHRA requires less oil.

Probably wrong size restrictor or is non ballbearing CHRA. There's many different size restrictors, depending on turbo you are fitting (I think it was the larger turbo's have bigger oil ways inside CHRA).

Yeah, the garrett website says 0.040" which is what size ones I put in.

This is a copy/paste from their website which I think has actually been re-worded since I read it a year ago, I don't remember them wanting 40PSI at the turbo, or that the .040 was the minimum size:

Remember to address all other potential causes of leakage first (e.g., inadequate/improper oil drain out of the turbocharger, excessive crankcase pressure, turbocharger past its useful service life, etc.) and use a restrictor as a last resort. Garrett distributors can tell you the recommended range of acceptable oil pressures for your particular turbo. Restrictor size will always depend on how much oil pressure your engine is generating-there is no single restrictor size suited for all engines. Ball-bearing turbochargers can benefit from the addition of an oil restrictor, as most engines deliver more pressure than a ball bearing turbo requires. The benefit is seen in improved boost response due to less windage of oil in the bearing. In addition, lower oil flow further reduces the risk of oil leakage compared to journal-bearing turbochargers. Oil pressure entering a ball-bearing turbocharger needs to be between 40 psi and 45 psi at the maximum engine operating speed. For many common passenger vehicle engines, this generally translates into a restrictor with a minimum of 0.040" diameter orifice upstream of the oil inlet on the turbocharger center section. Again, it is imperative that the restrictor be sized according to the oil pressure characteristics of the engine to which the turbo is attached. Always verify that the appropriate oil pressure is reaching the turbo. The use of an oil restrictor can (but not always) help ensure that you have the proper oil flow/pressure entering the turbocharger, as well as extract the maximum performance.

I had also installed the restictors to see if they would help with lag (I'd say they didn't much, but maybe a bit).

I don't think that too much oil could have caused damage that didn't come to light for a while - especially considering how short their lifespan was after I put the restrictors on. Especially if both turbos are damaged. I wonder how much new CHRA's are going to cost me. :/

[Skym]

From what I have noticed, it's sized to turbo being fitted (diameter of oilways inside CHRA which turbo rebuilders know about and that varies between turbo's) and might take oil pump psi into account (they don't mention it).

Ask Cherry and see what they say (always helps to talk to a pro, especially with oil restrictor size) -

http://www.cherryturbos.com/

But be aware HKS do mods to CHRA and some turbo rebuilders do mention these mods that need to be done to make the ballbearing turbo's reliable. Supposedly the old R32 RB20 turbo's (made by Garrett in Japan) have a reliable ballbearing CHRA (fail due to age or lack of servicing, lack of engine oilcooler).

Looked here for GT2871R turbo and they suggest .035" restrictor for ballbearing CHRA -

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-OIL-021&Category_Code=GRT

It's listed at the bottom here for that size turbo -

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Product_Code=GRT-TBO-022&Category_Code=GRT

Also the non ballbearing CHRA fitting -

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=ATP-FTG-029&Category_Code=GRT

[caliber676]

Possible that the restrictor got plugged?

[nismo-152]

Any chance you had a boost leak close to the front turbo? A leak can cause the turbo to overspin fall out of balance and eat itself alive if its significant enough...

[Marke]

Over oiling won't damage the ball bearing but will blow the seals.

If your actuators weren't balanced, it could have over boosted the front. I think they may have been starved of coolant when the line was damaged.

[Terrh]

I'm going to take the drain off and start the car and see what comes out. That'll tell me pretty quick if there's no oil getting there.

I have a set of HKS 2510's I'll throw on the car for this year while I send these out to get rebuilt.