Four turbos gone bad

[jeff1234]

Since i got my Charger i have gone through four turbos. The first one came with the car. I had it rebuilt by T/U and used his stock oil line. When that one went bad T/U rebuilt it again and this time i used Chris's braided steel line which he required for warrantee. When that one went bad he replaced it. I installed it and after a short period of time boost was reduced for an unknown reason. I replaced that one with a used one i got from Jackson.It lasted from the summer last year to this summer but not many miles. When i took it apart i found that it was completely worn out. Even the gas ring groove was wiped out. The turbo is on a 2.5, there is a restrictor in the block oil passage and although i dont idle the car for a bit when i finish testing the turbo has had a chance to spool down before i shut it off. Why are these turbos going bad? I can see one or two, but i just rebuild turbo # 5, What gives?

[supercrackerbox]

When you say restrictor in the block, I assume you mean in the passage to the cylinder head, which would be after the oil feed to the turbo?

Also, are you priming the oil pump to supply oil to the turbo before actually starting the car? Have you confirmed oil pressure to the turbo?

[blk86trbo]

I'd also check the oil distribution block on the front of the engine...make sure it's not screwed into the block so far that the oil passage is restricted.

[cordes]

All of the above. I would be very suspect of a lack of oil pressure going to the turbo. It's probably just low enough to kill them in short order, but just high enough to let them live a little while.

[4 l-bodies]

How much boost? Is this a stock compressor side? Mods to upper part of motor ie; ported head, exhaust manifold, intake, bigger exhaust? This sounds a lot like Mark Christofferson's father's solo II GLH.
Todd

[Aries_Turbo]

is the oil drain tube stock and free flowing?

i had a buddy that put his drain tube to the bottom of his oil pan below the level of oil and the turbo couldnt drain out and it nuked several turbos in a row.

Brian

[jeff1234]

Guys, us cellular sucks in Florida so it was difficult to get a signal. This is why I couldn't answer back right away.
Supercrackerbox, Yes, that the restrictor. Chris @ T/U was adamant about being sure that was in there. I do prime the oil pump when I install the turbo fresh. I have a mechanical gauge on the oil pressure block in addition to the pressure sensor. The lines are clear, I have to assume the preesure is what the gauge says.
Black86trbo, I checked the engagement of the OP block into the engine, it is only 3/8 of an inch so it is looking at a huge oil supply. I did bore out the feed hole to the OP block to ensure more volume. I think I am going to use the stock style oil line, it has a bigger inside diameter, I drilled the OP block to match that dimension. By the way Paul, thanks for your service!
Cordes, the turbo I just rebuilt was from T/U, it was the one that had reduced boost. I measured the free flow bearings as having a .005 clearance in the bore of the center section. I don't really know how much effect that would have on boosting, but that would be .010 slop over the length of the main turbo shaft. I had custom bearings made by Midwest Turbo that were set up at .0015. Hopefully that will help.
4 L-bodies, boost at best about 18-20. Stock compressor side, basically a stock T-2 (the one just burned up). Pro ported head 180 CFM at .550 lift on the intake. Exhaust manifold ported by me. Ehaust is 3" head pipe, 2 1/2 back to Magna flow muffler, straight through. What was the deal with Mark Christofferson's dad's GLH? What was his experience?
Aries_turbo, mine is correctly installed in the block.

[Ondonti]

is the oil drain tube stock and free flowing?

i had a buddy that put his drain tube to the bottom of his oil pan below the level of oil and the turbo couldnt drain out and it nuked several turbos in a row.

Brian

Or his motor has excess blowbye and and his crankcase evacuation system is not working properly or he needs to upgrade it.

Something as simple as disconnecting the oil drain and seeing how much oil flows from the outlet into a container at idle would be a great start. Hard to help without the basics.

Even the failures are not very clear. Are they even suffering the same failures?

[4 l-bodies]

Jeff,
In a nutshell. Mark's fathers GLH went through a turbo every year/two years. Very similar to your build except running only 15/16 PSI. Great flowing head, intake, and exhaust manifold, 3" exhaust with 3" TU swingvalve with a dead stock TII turbo. DSM BOV too. That thing ate up new and rebuilt CHRA's, it wouldn't discriminate (lol). It would wipe out thrust bearing eat up 4 piece backing plates and collars, and take out journal bearings. I had two turbo rebuilding shops inspect turbo and tell me the same thing. We were overspinning turbo even at 15 PSI!. Guy at one shop says let me guess ported cylinder head, big exhaust, intake mods. He pretty much nailed it. He said even at 15/16 PSI you are overspinning turbo because the motor has turned into a much more effcient air pump due to upper half of motor mods. Shaft speeds were WAY too high.
Since this was an autocross car we wanted zero lag or as close to zero lag as we could get. That is why we kept putting in stock TII turbos. Well we bolted in a s-46 hybrid in TO4B housing (old FM style housing) .63 exhaust housing and lag wasn't an issue at all. Car felt faster at 13 PSI than it ever did with stock turbo at any boost level. No turbo issues at this time. Myself and a couple friends have since ordered three more of these turbos from Cindy. Only change was some used different swingvalves. ATP, Rob's (shadow) welded 3+". All worked good.
Todd

[contraption22]

A stock Garrett will not last very long trying to do what you're doing.

[jeff1234]

This is valuable information to anyone considering building one of these cars. It should be the very first advise given to someone who is telling us he or she is going to build a high performance turbo Chrysler product. I certainly wish I had been told that, it would have completely changed the way I addressed the build of this car. At this point I will have the choice of rebuilding my turbo every year or lowering my boost. Being retired I certainly cannot afford an expensive replacement turbo. Reducing boost to about 12/14 psi may result in longer turbo life. The present turbo is spinning faster/higher and when combined with a bigger intercooler I think that the increase in power beyond 12/14 psi is more costly than it is worth. My best course of action is to accept what power I am able to get at those levels of boost with regard to longevity of the turbo. Even with a bad turbo I still hit a 14.78 at 106.7 on the street with my G-Tech. So that's pretty good.
A word of criticism and warning is indicated at this point. NOT ONE OF MY VENDORS HAS EVER WARNED ME ABOUT THIS, INCLUDING MIDWEST TURBO CONNECTION WHEN I ASKED THEM DIRECTLY WHAT MIGHT BE CAUSING THIS. There are two possibilities here. #1 the vendors don't know it, which calls into question their supposed expertise. #2 they do know and keep their mouths shut in order to keep making money rebuilding turbo's for the ignorant. Choose the one you think fits.
In the end the old saying that increasing the performance of any given car will reveal all of the weak parts, is absolutely true.. Chrysler knew what it was doing when it kept the boost levels low, even on the T2 models.
Thanks again for your help on this.
Jeff

[contraption22]

It's common knowledge that turbos only have a limited window of efficiency. The stock turbos on our cars were designed to feed an engine up to about 200hp with good reliability. Sure, people have made more than that with them, but the turbo didn't last long. The vendors address this by offering many turbo options depending on your needs.

[Vigo]

boost at best about 18-20. Stock compressor side, basically a stock T-2 (the one just burned up). Pro ported head 180 CFM at .550 lift on the intake. Exhaust manifold ported by me. Ehaust is 3" head pipe, 2 1/2 back to Magna flow muffler, straight through.

Oh look, another thread i am too late to help in! I also think you are just overspinning the turbo.

However, i think you're being entirely too pessimistic about eternally keeping the boost low. All you really need is an upgraded compressor side. A larger compressor wheel needs less rpm to move X cfm at X psi. If you were ABLE to to make enough power on a stock turbo, you clearly dont NEED to upgrade the whole thing. I would suggest getting at least a 60 trim or super60 wheel on your current or next turbo, and consider going bigger, too, like a 46 trim t04e wheel in a machined stock housing. It will affect spool to some degree but it also SHOULD lower the required rpm to hit your airflow needs, enough to make the turbo live longer. I wouldnt change the turbine section at all because it's already supporting your 18-20 psi power that you are happy with and can easily spin the compressor wheels i mention without issue.

Now, UNTIL you have the turbo off.. sure, i would lower the boost. But it should only cost you a max of ~$300 or so (at FULL pop) to get a larger compressor wheel put in your existing turbo, if it does not need any other repairs. It may cost less if you can find the parts yourself. If you get an entire bolt-on compressor section
(cover, wheel, backplate), all you're really paying a turbo shop for is re-balancing.

[jeff1234]

Out of all the posts I have made where I discussed the type of turbo I have and the modifications that I had made do I recall anyone ever telling me that my turbo was limited to 200 HP and explained the reasons why until now. Not one vendor that I have spent lots of money with has provided that information either. Probably because there is more money in rebuilds than there is in single sales of durable high quality turbos.

- - - Updated - - -

Question for VIGO's last post.
Because the car is apart right now, this may be a good time to change to the different compressor wheel. I know that I can get my turbine/shaft and compressor wheel rebalanced at Midwest Turbo Connection. Why is a different back plate required, Is the cover the same part as what I call the compressor scroll? Is the compressor scroll for the 46 trim TO4e larger that my stock T2? Is my stock T2 compressor scroll usable with the 46 trim TO4e compressor wheel with machining? If so where do I get that done.

[4 l-bodies]

Jeff,
If you go to a larger compressor housing (or scroll as you are calling it) it will require a backing plate mated to the housing and the wheel. For example a to4B will have a different backing plate than a to4E backing plate. You CAN have your to3 cover and backing plate machined for a 60 or s-60 t3 wheel, or even a 46 or even 50 trim wheel. If rebuilding yours again, better take a good look at the backing plate as they usually have damage to them if wheel has hit housing.
The compressor side will be far more effcient in a to4b or to4e cover though. You will also have turbo outlet mods and wastegate actuator mods to contend with if you go with the to4 frame compressor side. That is one reason for the beauty of the old FM style to4B turbos that only FWD seems to sell. They had TII mounting bracket provisions for the wastegate actuator designed into them. Be forewarned that even these turbos need a bit of fabrication to get to work. You can do a search on this forum bout that. I posted some pics of "issue" areas to address.
turbos_r_us on eBay is selling a upgrade kit for cheap. It uses the 50 trim to4e wheel in a modified t3 TI cover. Not exactly my first choice for a turbo upgrade, but it is inexpensive and might be a low cost option for you. http://www.ebay.com/itm/KILLER-Mopar...#ht_642wt_1170. A super 70 (to4B "S" wheel) or 46 trim would have been a better choice IMO for this guy to sell. Go big or go home right (lol)!
I think Harry (Tryingbe) was selling a to4E housing and wheel on this forum too. This would require some mods to make work. Better confirm shaft size is correct before purchasing this.
Todd

[Vigo]

My personal opinion, for whatever it's worth to you and in the company of relative experts like Todd, is that you should just have your existing compressor cover and backplate machined for a larger compressor wheel. I say this because ANY change of compressor cover to a different part is going to require other changes to go along with it, such as charge piping, wastegate bracket, intake system, etc.

There are compromises to running a larger wheel in a stock housing, but my opinion is that they are mild and not terribly important for someone who is not after every last possible HP. For example, there's a car in colorado that recently ran mid 11s at 5000+ft elevation on a turbo that has a 50 trim t4 wheel in a stock-style compressor housing. Even if you only get 85% of the performance of the bigger compressor wheel, it'll be better than 100% of what you've got, and it won't cause you any new headaches trying to make it fit and go back together.

As for why the backplate must be modified, it has to do with the exducer diameter of the compressor wheel. The exducer diameter is the largest diameter of the compressor wheel, at the 'base'. That part of the compressor wheel is inset into a small depression in the backing plate, so any change in that diameter must be accompanied by a change in the size of the 'hole' it sits in on the backing plate.

^With wheel.

^Without wheel. The machining will enlarge that inset area to fit the larger wheel.

[jeff1234]

Vigo, I understand the backing plate needing modification. The part that is not clear to me is if the cover for a T2 turbo must be modified as well. I hope to be able to use that one because of the mounting screw holes on the front of the cover for installing the wastegate actuator. Will the 50 trim T4 compressor wheel fit my shaft assembly correctly?

[Vigo]

Yes, the cover will need to be machined differently for the different size and shape of the new wheel. The outside of it will remain the same so everything will bolt or clamp to it the same as it does now. The t4 wheel has the same shaft size so that will also work. I think the 50 trim is overkill and would buy a 46 trim if i were you. Shadow has always spoken well of a stock turbine with a t4 46 trim compressor, and he has a lot of experience with 2.2s at a wide range of power levels. I saw a 46 trim wheel on ebay for about $60. Your turbo shop should be able to do the necessary machining on the compressor cover and backplate.

[5DIGITS]

Reducing boost to about 12/14 psi may result in longer turbo life.

This is true.
A stock T-II spins at 120,000RPM at 12 psi and 154,000RPM at 14 psi but please also consider that the intercooler PSI losses and that the loss increases as boost is raised.
Therefore, where the turbo can survive at the 154,000 at 14psi its reliability diminishes beyond 165,000+.
The 18-20 psi being used would put you well beyond the capable bearing/shaft speed limit while also considering the turbo is making 20-22+ at the compressor, to make 18-20 at the intake.

The advice given regarding the compressor exducer and machining of the backing plate, is very good information.
Putting a huge wheel in a stock/smaller housing can reduce the turbo speeds and lower inlet temps but it comes with increased risks of turbo surge and moves the wear to the thrust bearing.
Also remember that compressor mapping and their efficiency are based on the wheel AND cover combination.
This can take the 80% efficiency of a 50trim wheel in a 'E' housing to 70-65% efficiency in a significantly smaller cover.

[jeff1234]

I am checking machining and balancing costs but I could use more info. Does the trim number refer to the outside diameter of the compressor wheel in millimeters or something else. Also, how do I identify the various letter codes when referring to the cover, for example, what does "E" interpret to? Is it the stock T2 housing or something else. Is the thrust bearing the carbon seal in the backing plate or is it the round piece that is captured in what I call the oil distribution plate which locates on the roll pins in the center section of the turbo cartridge.