Need help sorting out boost issue

Scott & Heather · October 05, 2016, 08:21:40 PM

Ken Arnold has been such a wonderful resource and has spent some of his precious time fine tuning some programming settings on our ECM of our 8v92TA DDEC II. The changes he's made have made quite a difference. Tonight after his most recent magic, I am amazed how well the coach responds to throttle input. Wow...it's quite the monster. Had some nice hills to contend with and they didn't cause an issue whatsoever. I'm consistently passing most commercial trucks and can hold 70-75 mph for hours at a time even on hills. This all being said, we noticed I'm only getting about 14psi of boost. Cliff suspected we might have a turbo boost issue and it appears he was right. Ken checked our motor thoroughly and it doesn't appear like there are any obvious soot stains where boost might be leaking. At his recommendation I'll be putting a filter minder on to see if I have an intake restriction. Air filter is brand new.

Sent from my iPhone using Tapatalk

Jon · October 06, 2016, 03:13:58 AM

Scott, assuming the turbo is in good shape, finding leaks on the manifolds of the 8V92 requires a very discerning eye. One area that is typical is at the ends of the manifolds at the rear of the block.

That is an area that typically is black and dirty so sooting is hard if not impossible to see. If I remember correctly the ear on the manifold can crack and that is hard to see, but also the manifold gasket can fail in that area.

luvrbus · October 06, 2016, 05:27:01 AM

They don't run on high boost pressure just cruising down the road 10 to 14 # is normal,a long hard pull it should increase up to 18 to 21 psi.

Air filter toss the factory air filter assembly and install a ECO system with 1500 cfm your engine will love it,the factory air filter was for a 400 hp engine lol don't buy the K&N I do not want to be shipping you parts

uncle ned · October 10, 2016, 03:23:13 PM

Scott you have met the eastern version of Cliff and Don put together.

Then we have Gene and David also. Would put BK in that group.

But he just likes to drive and eat, don't we BK.

uncle ned

Scott & Heather · October 11, 2016, 06:02:47 AM

Lol. Well I have yet to meet Cliff. But we are hoping to meet him before I turn 95. Here's where I'm at right now:

Today my filter minder arrived at NAPA. I'll put it on and see if I have any measurable restriction. I'll take Cliffs advice and upgrade to the eco filter if I can find the proper part number for my C3. I am tightening all clamps. I'm also changing the oil today and doing a couple of other maintenance items before I hit the road again Thursday. I'm hoping to pay Scott Crosby to help me with a couple of other things while we are in Indiana for a week (trans fluid/filter change, etc). I'll report back.

Sent from my iPhone using Tapatalk

blue_goose · October 11, 2016, 07:00:16 AM

Do you have the Silverleaf yet? Hard pull, engine at max power no less than 26 lbs. If more that is good.
Jack

lostagain · October 11, 2016, 07:29:38 AM

Scott, you won't find the proper part number for an Eco filter for a C3. You have to look for one that will fit in your available space, with the right size in and out openings (5" probably), and the right orientation (coming off the ends, or one pipe on the end, the other at a 90* angle, etc). And of course 1500 cfm. I would get the biggest one that fits in your space. Some are unidirectional, some you can use either way. Lots to choose from. Donaldson has them. Other brands carry them too, I think?

I have been using one for 3 or 4 years now since Clifford convinced me. I love them. I don't replace them as often now, since I moved the air intake high on the side of the bus near the roof. I cut one open once to look. Very well made. Doesn't look like they could come apart even soaking wet.

JC

uncle ned · October 11, 2016, 09:22:33 AM

Scott I forgot to mention the other scott. only met him once at Blytheville.

Seemed like a nice young man.

And loves to work on old Detroits and has a nack for mechanical things, wish i was a little younger.

Did Ken let you ride in the "PREVOSE" a amazing piece of work.

uncle ned

Iceni John · October 11, 2016, 10:03:12 AM

Quote from: lostagain on October 11, 2016, 07:29:38 AM
Scott, you won't find the proper part number for an Eco filter for a C3. You have to look for one that will fit in your available space, with the right size in and out openings (5" probably), and the right orientation (coming off the ends, or one pipe on the end, the other at a 90* angle, etc). And of course 1500 cfm. I would get the biggest one that fits in your space. Some are unidirectional, some you can use either way. Lots to choose from. Donaldson has them. Other brands carry them too, I think?

I have been using one for 3 or 4 years now since Clifford convinced me. I love them. I don't replace them as often now, since I moved the air intake high on the side of the bus near the roof. I cut one open once to look. Very well made. Doesn't look like they could come apart even soaking wet.

JC

I use the largest Racor ECO-BC filter made, the 094973002 model that has more than enough CFM for my engine. It has a 7" top inlet, a 7" lower side outlet, a one-way drain in the bottom in case rains gets inside, and it seems very well made. When I got mine I could not find anyone in the entire country that had one in stock! Harbor Diesel in Long Beach CA quoted the lowest price, and it was made to order for me by Racor in Modesto CA - this way it was not sitting on a shelf somewhere for ten years drying out and becoming brittle.

After I installed it I notice more power and the turbo whistles louder, so I guess the old filter was constricting the engine. I now get 26 PSI at full boost. Just make sure your air intake is high so it can't suck in road dirt.

John

eagle19952 · October 11, 2016, 11:05:30 AM

does anyone use a manometer anymore ?

with filter out (Housing closed as operational) and then filter in ?

luvrbus · October 11, 2016, 11:13:05 AM

Quote from: Scott & Heather on October 11, 2016, 06:02:47 AM
Lol. Well I have yet to meet Cliff. But we are hoping to meet him before I turn 95. Here's where I'm at right now:

Today my filter minder arrived at NAPA. I'll put it on and see if I have any measurable restriction. I'll take Cliffs advice and upgrade to the eco filter if I can find the proper part number for my C3. I am tightening all clamps. I'm also changing the oil today and doing a couple of other maintenance items before I hit the road again Thursday. I'm hoping to pay Scott Crosby to help me with a couple of other things while we are in Indiana for a week (trans fluid/filter change, etc). I'll report back.

Not saying Scott couldn't do the fluid change but sometimes the 755 and 748 Allison start throwing codes when the fluid is changed it's best IMO take it to Allison just in case they have equipment to delete those codes BTDT

Sent from my iPhone using Tapatalk

Scott & Heather · October 11, 2016, 05:47:05 PM

Good to know. Striking the trans flush for now then. Ok just put on a filter minder and floored the throttle. Not getting any restriction. I mean the yellow disc drops to literally the first line (the least amount of restriction). So do I still need to upgrade to the eco? What are the chances my MAP sensor needs to be replaced?

Sent from my iPhone using Tapatalk

luvrbus · October 11, 2016, 06:54:30 PM

They don't use a MAP sensor,what injectors and turbo did Ken say you had ? I am sure the 450 to 500 hp used the 4475 injectors and the TV 8513 turbo with a A/R of 1.39 and the 400 hp MCI used the 4915 injectors with the TV 8513 turbo with the A/R of 1.23.The A/R of 1.23 may not be enough but I'll check on that for you

B_K · October 11, 2016, 09:37:26 PM

Quote from: luvrbus on October 11, 2016, 06:54:30 PM
They don't use a MAP sensor,what injectors and turbo did Ken say you had ? I am sure the 450 to 500 hp used the 4475 injectors and the TV 8513 turbo with a A/R of 1.39 and the 400 hp MCI used the 4915 injectors with the TV 8513 turbo with the A/R of 1.23.The A/R of 1.23 may not be enough but I'll check on that for you

He's right they don't have a MAP sensor!
They do have a BOOST sensor that LOOKS like a MAP sensor, but it is a Detroit Diesel part and is MOST DEFINITELY NOT A MAP sensor!

BK

Scott & Heather · October 12, 2016, 04:08:29 AM

Ok correct me on this, when I look up the part number for the turbo boost sensor (little guy that has a 1/4" vacuum hose running from it to the turbo housing) it comes up cross referencing with a GM map sensor. Are they just using a MAP sensor as a turbo boost sensor?

Sent from my iPhone using Tapatalk