turbo reliability on track
10-05-2010, 07:36 PM
#41
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with all this talk about reliability - whens somebody going to organize
"Marauding Miatas 2011"
one-lap-of-america style tour of the best tracks in a region while terrorizing the local v8/subi/evo/etc inhabitants.
some thoughts: select 2 weeks in summer to hit 7 tracks for an easy vacation. or perhaps go crazy and do 5 in one week.
if enough folks participated, could probably ask for own run group.
"Marauding Miatas 2011"
one-lap-of-america style tour of the best tracks in a region while terrorizing the local v8/subi/evo/etc inhabitants.
some thoughts: select 2 weeks in summer to hit 7 tracks for an easy vacation. or perhaps go crazy and do 5 in one week.
if enough folks participated, could probably ask for own run group.
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10-06-2010, 01:11 AM
#43
Yep, 94 Protege stock Bottom end craigslist and a, stock 99 Miata head. The 94 Protege came stock with 9.0:1 pistons.
The big thing is I am not getting lots of oil past the rings and dealing with wierd oily cumbustion mixes with it. it just keeps on going. The last time I ran this setup I broke a valve which made a big mess but I think that was a freak occurance combined with a 7400 rpm rev limit.
Bob
The big thing is I am not getting lots of oil past the rings and dealing with wierd oily cumbustion mixes with it. it just keeps on going. The last time I ran this setup I broke a valve which made a big mess but I think that was a freak occurance combined with a 7400 rpm rev limit.
Bob
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10-06-2010, 02:20 PM
#44
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Oil wetting down spark plugs, again.
Burnt exhaust valve, again.
Wear and score marks on cylinder walls, again.
Damage to rod and main bearings, again.
I saw no degradation in compression or loss of power along the way just increased oil consumption and increasing oil smoke out the tailpipe over time, especially under load. I think the burnt exaust valve stems from the problems caused by Oil in the combustion chamber.
I cannot say with certainty what exactly is causing the issues but running the same turbo setup at the same boost with a stock un-touched internals in the motor has not produced the same wear degradation over time as the built motor. Lost a bit of torque and power due to less displacement is all.
Bob
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10-07-2010, 01:43 PM
#46
Started consuming more oil, again.
Oil wetting down spark plugs, again.
Burnt exhaust valve, again.
Wear and score marks on cylinder walls, again.
Damage to rod and main bearings, again.
I saw no degradation in compression or loss of power along the way just increased oil consumption and increasing oil smoke out the tailpipe over time, especially under load. I think the burnt exaust valve stems from the problems caused by Oil in the combustion chamber.
I cannot say with certainty what exactly is causing the issues but running the same turbo setup at the same boost with a stock un-touched internals in the motor has not produced the same wear degradation over time as the built motor. Lost a bit of torque and power due to less displacement is all.
Bob
Oil wetting down spark plugs, again.
Burnt exhaust valve, again.
Wear and score marks on cylinder walls, again.
Damage to rod and main bearings, again.
I saw no degradation in compression or loss of power along the way just increased oil consumption and increasing oil smoke out the tailpipe over time, especially under load. I think the burnt exaust valve stems from the problems caused by Oil in the combustion chamber.
I cannot say with certainty what exactly is causing the issues but running the same turbo setup at the same boost with a stock un-touched internals in the motor has not produced the same wear degradation over time as the built motor. Lost a bit of torque and power due to less displacement is all.
Bob
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10-07-2010, 02:28 PM
#47
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I think a combination of stock oil squirters and pistons with gas ports to the oil control rings positioned so they serve as high pressure oil injectors for the rigs is a major contributor to oil consumption. but it still doesn't explain the rapid wear rate.
When it goes back together the squirters will be plugged. FWIW FM is now plugging all the squirters on theire builds. Bill said he was going to do it to mine but he didnt.
Bob
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10-07-2010, 05:07 PM
#51
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this thread is awesome. thank you guys for shaving so much information!
on a seperate note, do you guys think its better to have a turbo water AND oil cooled? or would you prefer just oil cooled? i think the water cooling is nice but more parts that can physically break...maybe if done properly its not a big deal?
on a seperate note, do you guys think its better to have a turbo water AND oil cooled? or would you prefer just oil cooled? i think the water cooling is nice but more parts that can physically break...maybe if done properly its not a big deal?
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10-07-2010, 05:28 PM
#52
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I've seen many returns of damaged turbos from customers whos builders and suppliers said they should be OK w/o the water hooked up. We didn't design them into the center hsg as an option. For severe applications it's even more critical! If you don't use the water ports the durability of the BB cartridge is greatly reduced and it will fail prematurely. I've created presentations and tech tutorials, which are on www.turbobygarrett.com, on the very subject.
ref: http://nissanroadracing.com/showpost...9&postcount=32
Last edited by jasonb; 10-07-2010 at 05:40 PM.
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10-07-2010, 07:05 PM
#54
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I suspect others running the **** out of there cars on the track with aftermarket pistons are also having oil control issues. Just haven’t identified it. I suspect the low height Stroker pistons makes it worse.
Bob
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10-07-2010, 07:18 PM
#56
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Bob
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10-07-2010, 09:50 PM
#57
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another tidbit on the water cooling which i didn't see mentioned on the web page sited earlier:
In thermal siphoning water is circulated by natural convection because of the difference in water density at different points in the system. The water in the center hsg is heated due to heat soak back from the turbine hsg. This water is hotter than the water lower in the system therefore the lower density hot water in the center hsg is pushed out by the higher density cool water. This cycle continues until the water throughout the system is the same temp, which in turn cools the center hsg slowly therefore eliminated choking of the oil. The presentation contains other components as well but since it was a presentation it's missing some of my notes. Let me know if you have any questions.
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10-07-2010, 10:15 PM
#58
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I haven't seen it if I am, and I just ran 5-hours over two days and never lost any measurable oil while checking plugs the first day for a spark problem. I have no aero however, so I don't see the lateral g-loading that you do.
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10-07-2010, 10:31 PM
#59
i can't speak from personal experience, but a garrett employee stated following on another forum about garrett ball bearing turbos:
he followed up with follow link (half way down has discussion of importance of water cooling): http://www.turbobygarrett.com/turbob...imization.html
ref: http://nissanroadracing.com/showpost...9&postcount=32
he followed up with follow link (half way down has discussion of importance of water cooling): http://www.turbobygarrett.com/turbob...imization.html
ref: http://nissanroadracing.com/showpost...9&postcount=32
Summary: if you want your bb turbo to fail, do not attach water lines to it.
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10-08-2010, 06:48 AM
#60
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And to add another data point - he's been using inconel studs on his car for the past several events, and that seems to have eliminated his problems with manifold bolts stretching and resultant warping of the mating surfaces.
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