Things I'm doing to improve boost (pics)

[Scott & Heather]

Ok, I have a little bit of time to make three things happen before heading from Texas back to Michigan in June. I need some quick advice. My boost levels are 10-12 and should be higher according to Ken Arnold who has been my awesome personal tech on my turboed 8v92 DDEC II that has a 500 hp program on it. 1992 MCI 102C3

1. I am installing a higher flow muffler. Any recommendations? Sean Shanks installed one I liked but I can't remember the details.

2. Rebuilding the air filter housing and installing higher flow air filter. Cliff, you made recommendations on a 1500cfm filter. What was the company that made this?

3. Turbo boost sensor. I'm going to replace it with a new one and replace the hose too while I'm at it. Question is: two bar or three bar? No one has definitively answered my question on this yet lol.

Anything else? My turbo is fine, my exhaust doesn't seem to have any leaks. But the coach is running hot all the time (new radiators and fresh coolant and no air pockets. We burped those all out). And doesn't have the power a 500hp coach should. Fuel filters are new. Trans is Allison 748 ATEC. 1992 MCI 102C3.




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[buswarrior]

Wrap the exhaust, pre-turbo, to keep the heat IN.

Put a wrench on the exhaust manifold bolts to be sure...

Be very suspicious of the size of the stock air intake cavities making obstruction for your fire snorter.
There was at least one busnut that put a giant Y in the intake pipe and plumbed two air cleaner canisters to let that beast gulp freely.
No need for symmetry, stuff  'em in where they'll fit.

Keep the bends to an absolute minimum, and as gradual as space and ingenuity allows.

With a scientist's OCD, be absolutely sure that your boost measuring devices are properly located and telling you the truth.

Proudly purchase the good constant torque clamps, put quality lube on 'em so they will come off next time.

happy coaching!
buswarrior

[eagle19952]

everything in Alaska that is not paved is made of glacial silt mixed with poor gravel.

We always swabbed the intake piping with a very light film of 90 weight.
It goes no where, but it definitely detects dusting of the intake.
Check it often to insure the integrity of your intake.
Especially when revamping.

[bevans6]

Both the ECO air filters and muffler/resonators can be Donaldson, the advantage being a giant catalog full of bits and bobs for your install (those constant torque straps, for example, and all the sleeves and bends) and easy access to stockists.  one BAR is roughly 15 psi, so a 3 BAR sensor would probably be appropriate.  Some would depend on if your gauge/sensor combo is designed to measure absolute pressure, so the first BAR is basically measuring ambient atmospheric pressure, or boost pressure, with zero on ambient and 30 of 45 psi of boost.

[dickegler]

Boost is a  function of fuel delivery. Inspect fuel lines for integrity,and blow out dip tube in tank. I have seen many power problems solved by removing a fuel restriction before the filtering system
Perhaps plumbing a five gallon can of fuel and a test drive would give a clue.

[blue_goose]

When I bought my 102C3 it had the MCI muffler and the standard air intake that they used for the 8V92.  It ran lake a sports car.  Never slowed down for a hill.  You do have a problem, but I don't think it is the parts you are looking at.  I would be looking for a problem in the exhaust system.  That could be the muffler.  Take the exhaust pipe off before the muffler and give it a ride with a straight pipe.
Jack

[luvrbus]

Scott,you are not going see over 15 lbs of boost under normal driving conditions with that engine,boost should rise to 21 to 28 lbs under a heavy load though.
Buy a Aero muffler like Shanks and install the ECO 1500 air cleaner it should help.
You need a chassis dyno and the only place I know that will dyno a older bus is WW Williams in Tucson Az costs $180.00 Williams won't do it Phoenix.
Since you are in Texas call Stewart and Stevenson in Houston about a chassis dyno.Did Ken check the injector numbers,blower and the engine cam number to be sure you have the right components for a 500 hp engine ?.
I can send you a new by pass valve for the blower if you want to try it, a bad by pass valve will affect boost have you serviced the by pass valve ?    

[Scott & Heather]

BW: excellent info and advice. My current intake setup has a 180 degree u turn. I'm eliminating that. Boost measuring device was the prolink setup ken was using. A computer. I like the two filter idea... very intriguing. And I do think I'll wrap the exhaust up to the turbo.

Don, I am nervous about revamping my intake system for this very reason. I'll be checking and double checking to be sure I don't mess up and leave a leak. I'll use smoke and pressure. And I'll use your advice and oil the inside lightly.

Brian: the ECO was the one I was thinking of. Thanks also for the info on the sensor. That helps me a lot. I think I have a two bar. I'll cross reference the part number.

Dickegler: I have plenty of fuel. Tons and tons of rolling black smoke when I'm on the throttle. Seriously. I'm a freaking freight train. We turned up fuel so yeah.

Jack: this is exactly what I'm expecting. It should move quick. I'll be removing the muffler and going with a higher flow unit.

Cliff, that's just it, we were pulling a hill towing my 7000lb land cruiser and ken was sitting shotgun watching the computer screen plugged into my ECM. We maxed out at 12psi. He really felt it wasn't enough and he also felt the coach was sluggish. Still better than my 6v92 was but definitely not a strong as when we first bought it. I'll see if any of the S&S shops here would dyno it.  We haven't checked any of the blow and engine cam numbers. I just assumed that my 400 hp 8v92 TA could be bumped to 500 without any drama?  I will take you up on the bypass valve offer if I can't fix it with these three tries.


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[luvrbus]

Be sure the pipe leaving the turbine (hot side) is at least 5 inch,I had a Eagle here that somebody had reduced the pipe to 4 inch for clearance reasons it was one a sick puppy

[sledhead]

I ran a 10' copper 1/4 " line from the engine then to a 1/4 " dot air line up to the dash to the old style ( new ) air boost gauge . always got as high as 25 -30 lbs and then I see that I am only getting 18-22 lbs ?? looked at the manifold and there was a very small area of  black soot ? so as I removed the manifold it just fell apart in 2 pieces ? so I replaced both manifolds and gaskets and bolts . got my boost and power back this was on the mci


now after reading your post I went out and looked at the air restriction gauge at the air box and it shows a little restriction ? the air filter is new and I put it in on sept 15 th last year ? so I pull the air filter out and I have some of last years dried leaves ( small pieces ) that must have come through the screen on the intake . use the shop vac and all is clean now . so now I will inspect the filter more often   on the cat

not that I could tell any power loss or fuel burn

dave

[Scott & Heather]

Cliff, will
Check that and report back.

Dave, I indeed have spot around the area where the exhaust side of the turbo clamps to the intake turbo. I removed the v band clamp and will replace it with new.


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[Scott & Heather]

Ok so I pulled the vband clamp off the union between the cast exhaust turbine and the turbocharger. There is indeed soot around this area. But the soot isn't coming from the actual union but it seems to be coming from the cast turbine housing just before the vband clamp union. Can someone interpret these photos?


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[eagle19952]

there is a "piston ring" like seal in there...my guess, it is stuck...or not sealing...

i think

[Scott & Heather]

Donald, I know there are three piston ring type compression seals inside the down tube of the exhaust turbine exit portion, is that the ones you're talking about? Or is there indeed a similar ring seal between the turbocharger and exhaust (hot) turbine housing? If you're right, how do I r&r this?


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[eagle19952]

atypical: