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Author Topic: What kind of turbo is this?  (Read 1100 times)
lostagain
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« on: December 30, 2012, 06:38:00 PM »

Pulled the turbo out of my bus today. I never thought I had very much power. This summer, I installed a boost gauge and it only shows 10 psi max. I get black smoke when I step on it. Well I know why now: the wheel doesn't turn freely, it takes some effort to spin it with my fingers. It is somehow coked up or fouled up. So this brings the question: do I rebuild what I have, or look for something more appropriate to my circumstance? It is a 6V92 with 9B90 injectors timed at 1.47". I cruise at 65 mph at 1800 rpm since I re-geared with a 3.42 rear end. The turbo has a .95 A/R. The Detroit ID plate on it says: model number: 5102353, serial number: JK0292. Would anybody know what kind of turbo I have, and is it the right one? I have some charts I looked at, but those numbers don't show up on them.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
chessie4905
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« Reply #1 on: December 31, 2012, 06:13:49 AM »

  Part number shows up on my 92 series service manual under section 14: engine tune up under Federal and California coach and non coach engines. It is listed as used with all 6V92 engines The A/R is 1.23. It is listed as a TV8102. 1.470 injector timing, except for Calif engines which are 1.490 Throttle delay .570; Calif .636. These settings are for 9B90 injectors;all at 2100 rpm's. Service manual part number is is 6SE380
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lostagain
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« Reply #2 on: December 31, 2012, 07:43:57 AM »

Thank you, Chessie. I see it now in my manual too. So someone changed the compressor side from 1.23 A/R to .95. What difference does it make? I don't understand what the A/R does. I would like the peak torque sweet spot at 1600 to 1800 rpm for cruising.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
luvrbus
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« Reply #3 on: December 31, 2012, 07:53:42 AM »

 There are 2 A/R on a turbo 1.23 A/R  is good for the hot side that number is stamped inside the turbo JC what is the compressor side something is way off your 6v92 should be up around 20+ lbs with 9b90,I have a set of 9g90 and 9g85 if you stop by I give those to you, the 9B90 injectors need to be gone
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lostagain
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« Reply #4 on: December 31, 2012, 08:14:38 AM »

Clifford, are you saying that 1.23 A/R refers to the hot side (turbine)? The .95 is stamped inside the compressor horn on my turbo. I'll go to the shop and look again for a number inside the hot side.

The reason I get only 10psi boost is because the turbo wheel is stiff. It is fouled up with old oil or something and obviously wouldn't spin freely. Once this is fixed and spins freely, it will put out boost in the 20s, I hope.

I just need to figure out whether the turbo I have  now is the right thing. If it is, I will rebuild it or have it done. If not, I want to get the right parts that will give me the best performance.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
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« Reply #5 on: December 31, 2012, 08:31:42 AM »

Should be 1.23 on the hot side,the TV 8511 is a better choice IMO
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lostagain
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« Reply #6 on: December 31, 2012, 09:10:46 AM »

So it looks like there is a 1.23 inside the hot side horn. It is faint. The cast iron is pitted, makes it hard to see.

What is the difference between a TV8102 and a TV8511?

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
lostagain
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« Reply #7 on: December 31, 2012, 09:41:41 AM »

I see in the charts in the tune up section that a TV8511 is for 8V92. Most of them have a 1.39 A/R, some a 1.23 A/R. Does a 1.39 give more or less boost than a 1.23? And do they all have a .95 compressor? Or do they come in different sizes too?

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
luvrbus
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« Reply #8 on: December 31, 2012, 10:17:44 AM »

JC I know you have enough intake cfm or at least the filter does this is what you should have for exhaust cfm

exhaust temp 850 F @ 1800 rpm
intake 1225 min cfm
2972 cfm exhaust flow

formula
exhaust temp +460-540
x intake cfm = exhaust flow at 1800 rpm

when you get those numbers right that engine will not smoke and the turbo boost will be around 20-23 lbs with your turbo setup

good luck
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Don Fairchild
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« Reply #9 on: December 31, 2012, 10:36:07 AM »

J.C

If it were mine I would go to either a 9A90 or 9G85 or 9G90 injector set at 1.460 and a TV7511 or 7512 turbo with a 1.23 hot housing.

The A90 B90 and G85 have the same fuel flow but use a diffrent tip The A&G use a 9-62 tip (better atomization better burn) and the B uses an 8-68 tip the G90 uses a 9-6 tip and flow's a little more fuel.

Just saying.

Don
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lostagain
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« Reply #10 on: December 31, 2012, 04:32:43 PM »

Thanks all,

learned a lot from you guys, again, thanks.

I'll be looking for a TV7511 and some injectors in a couple days after New Year's. I'll let you know what I find. Can't wait to have this engine running right!

Happy New Year to all my busnut friends.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
luvrbus
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« Reply #11 on: December 31, 2012, 06:44:04 PM »

 Does the engine have a bypass blower ? mini or full bypass or none

good luck
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« Reply #12 on: December 31, 2012, 06:51:50 PM »

From my sperience, the 6v turbo used on the 8V sure makes for a snappy engine along with the 9200 injectors at 1.460.
Had to make the air box covers from 7/16 plate (what we had in stock) as the cast aluminum covers break off, how much boost, no idea but enough LOL
Dave M
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lostagain
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« Reply #13 on: December 31, 2012, 07:38:19 PM »

Clifford, you had me put on all my winter clothes on to walk out to the shop to go look. Yes it has the mini by-pass at the back of the blower.

JC
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JC
Invermere, BC
1977 MC5C, 6V92/HT740
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