ISB 300hp

[Frank05]

Good morning all,

So I have purchased a used 2001 monaco knight with a 300 hp Isb comings engine, I feel that the 300hp is under powered to push the 26 thousand pound coach, my turbo boost is around 15-18 psi wide opened, is this about the right boost, or should I start looking for leaks, my concern is that I want to start towing a 3700 pound jeep liberty on my trips, I have done some reading on banks power, but have found nothing referring to the 300hp ISB, is there something that I can do to get a bit more power out of the engine, oh it's a cast block 54 with a Allison mh3000,
Any help would be great.

Thanks Frank

[bachler]

The statement Leaves a lot of room for discussion;; #1 the 300 HP is not an over powered Unit. However it has a torque rating that is near twice that of the Gas engine with equal CI. which is about 440, It will do just fine, And you really don't want to go any higher with your boost, That is allready near 20 to 1 compression rating; which is stressing things close to the limit; Remember that old saying;they lost the battle but won the war., When we pull a long grade I set the tach. at 1750 and let it pull. My friend runs his at 2250 , Mine is a 330 his is a 270; Which is right ????? we both get there about the same time. 300 HP plenty of torque. Life is good.

[Frank05]

So you think that I will be fine pulling 3700 pound around?

[Airtool]

See trans spec. info. attachment. This is the limiting factor,to much power and something is going to brake.
Your ISB maybe rated at 300 HP,but the torque is limited to the max.that the transmission can handle. This setting will also limit the boost allowed.The ECM is programed to protect the drive train.
Banks equipment for the ISB series will fit all of the Engines,from the De-rated 275 HP up to the 330 HP+.
Changing the engine hp requires looking at everything in the drive train.
Torque Converter, Transmission,Drive Shaft and the Rear Axle in some cases.
The weakest link will brake first and you have to go from there.

Some numbers to think about, only an example!!!

600ft.lbs at flywheel * 3 in low gear=s1800ftlbs on drive shaft *
4.5 Axle ratio=s 8100ftlbs at the wheel hub.

Some impressive numbers !!!

Dick.

[Airtool]

On a 3to4% grade you will not even know its there. when climbing steeper grades it will keep shifting down as speed decreases, but power is not a problem. Diesels will climb any thing you put in front of them.
Heat is the thing that you have to keep under control.

Dick.

[srydve]

I have an '04 5.9 300hp and according to my silverleaf engine monitor my boost pressures get up to 29 and on long hills it's up there a lot. I don't know if this indicates you have a problem ( or my silverleaf is wrong) but I think further investigation is warranted, I would give Cummins a call and see what they say.

[Airtool]

Good eye Dave,Frank mentioned a 3000 series transmission. I was thinking the 1000 / 2000 series. Duh!! You are correct in thinking up to 29 psi for the boost.
Frank if you are reading, just for fun check the air supply line to the air compressor. comes from the intake manifold area to the Compressor. They do fail and this reduces the boost,with your reading good chance there is a failure in this hose.
Check all the other hoses from the turbo at the clamps and around the input manifold.

Dick.

[Frank05]

Quote:

Originally Posted by Airtool Good eye Dave,Frank mentioned a 3000 series transmission. I was thinking the 1000 / 2000 series. Duh!! You are correct in thinking up to 29 psi for the boost. Frank if you are reading, just for fun check the air supply line to the air compressor. comes from the intake manifold area to the Compressor. They do fail and this reduces the boost,with your reading good chance there is a failure in this hose. Check all the other hoses from the turbo at the clamps and around the input manifold. Dick.

Dick,
I have checked around the turbo ( hoses clamps), I have no idea where to look for the compressor, like I stated I'm new to the pusher family, however I think that there must be a small leak 15-18 psi seemed low to me, so any ideas or suggestions on what/where to look for this compressor?

[Airtool]

I will post some pictures or drawing for you to lock at.I will take a couple of minutes to get the proper files pulled of the drive(s)

Dick.

[Mr_D]

Quote:

Originally Posted by Airtool See trans spec. info. attachment. This is the limiting factor,to much power and something is going to brake. Your ISB maybe rated at 300 HP,but the torque is limited to the max.that the transmission can handle. This setting will also limit the boost allowed. Dick.

OP has a 3000MH, it's rated for 1200 ft lbs torque and at least 400 HP behind an ISL 400. No way is the ISB going to stress it.

We have an ISC, stock the boost was about 25 psi, with the Banks we're showing 35 psi.

[Frank05]

Quote:

Originally Posted by Mr_D OP has a 3000MH, it's rated for 1200 ft lbs torque and at least 400 HP behind an ISL 400. No way is the ISB going to stress it. We have an ISC, stock the boost was about 25 psi, with the Banks we're showing 35 psi.

So are you saying that I should look into a banks system?

[Triker56]

You should be getting at least around 23 PSI boost with the OEM ISB.
Keep checking for leaks. Check the hose that comes out around/behind the air compressor for a hole in it. On the passenger side of engine below the AC compressor.

Banks PowerPack turbo will pick it up to around 34 PSI on the ISB and improve the OEM 660 ft lb torque.

[Airtool]

Frank,some pictures for you to look at. I have got to take time to put some lines and notes on the pictures at some point.

Frank the file is to big to post on the page. We will have to find a different way to get them to you.

Dick

[Frank05]

Dick,
you can send them to my email address
ohigginsk@verizon.net