My Cumins 5.9 is a great engine except for the total lack of power. I can go from zero to sixty in 5.5 DAYS.

Seriously, are there any upgrades I can install on the engine to improve performance? For example, a different air intake system? I have a turbo now.

Thanks,
Rick

Both MWrench and Gary Carter have made significant power enhancements to their 5.9Ls.

If you have the time you can find tons of info here:

http://www.cumminsforum.com/forum/

NT

Hi Rick, There is an adjustment on the P pump (injection pump), that will greatly improve the off line power and if done right, will not smoke to badly. Yes, there are power adders for this engine, but I haven't gone there yet. You are probably heavier then I am so it will be worse then mine for sure.

I will take some pictures and do a write up after I get back from this trip ~Aug 10-12,

turning up the pump is an easy job but the advice that I get is that you had better put a thermocouple in the exhaust and watch for heat. It becomes much easier to damage the engine. About 130hp is available, but remember the upper limit for the Allison 4spd is 250. and would bet that it burns more fuel too. No free lunch.

EGT is always as good idea when upgrading an engine above what the factory specs are.

Without a replacement calibration plate, you can not get a lot of HP by just turning up the pump, but you can get a bit more fuel from idle which will increase the boost rate, that in turn will improve off line acceleration. The adjustment screw can only be turned 1 turn or less, more then that you will have an excessive amount of smoke and will have much higher EGT at full throttle for extended periods of time.

Fuel consumption for me did not increase, I spend much less time accelerating so the trade-off isn't negative. I could only turn mine up 3/4 turn, more then that, I could kill all the mosquitoes for miles around. (I would need to talk to Al gore about buying some carbon credits!)

Recalibration, dual air inlets, larger exhaust, and larger injectors would be required for major gains in HP.

The 230 HP turbo has the smallest hot section available for this engine to improve spool-up time so there is really no turbo solution without major engine mods as mentioned above

quote:

EGT is always as good idea when upgrading an engine above what the factory specs are.

Gages' main functions are to show if a component is being overstressed or is misbehaving. IMHO, besides the usual (Oil pressure, voltmeter, tach, coolant temp) gages for boost, EGT, and tranny temp are essential for any turbodiesel motorhome.

BTW, as someone else here on the Forums has stated, "Diesels do not accelerate. They merely 'gather momentum'." And that applies to my Breakaway that probably has the highest power/weight ratio of any Barth (Gary Carter's and MWrench may be exceptions). I measure acceleration in Furlongs per Fortnight...

quote:

Rick

Richard you say you have a '94 which means that you should have the 6 speed transmission. This would also have the 230hp engine. If this is true you can pump out much more power, up to 400 but your transmission would not handle it. If you still have the 542 allison you need to keep it down to about 230hp.

Ok I have had close to 400hp out mine and that kinda scared me so backed it off. Was able to get almost 40 pounds of boost at that time. Just didn't know what would break first.

Anyway I have the banks split intake manifold and the larger banks waste gate turbo. Boost gage, and pirometer for exhaust temp. Changed the fuel plate in the pump and was still slow. Last I replaced the stock injectors with marine injectors.

Also replaced the 543 allison with a 2000 allison with lockup and overdrive.

And finally fuel econony increase about 1 mpg. But now I drive 65-70 at 16-18 hundred rpm. With a 3.73 rear end it is still a little pokey off the line but then anyone want to drag.

Richard, IIRC you have a 32' or 34' Breakaway, do you have 22.5 tires? If you do and you have the same diff ratio that I have, 4.1:1, it will be a real dog off the line! I know of one other longer Breakaway that has this combination and the trans doesn't shift into 6th until ~70 something, way to high gearing. Yours may be the same.

Mine shifts into 6th at 57-58, and with the new tires runs 2000 @ 70 MPH (lost about 50-60 RPM with the new tires) and even with this combination the initial acceleration is not great. Once it is in second and the boost is up ~20 lbs. it is OK.

Hi,

I shift into 6th gear at exactly 65 mph. At highway speed the engine runs great. It's been just the last couple of months that it really seems slow starting from a dead stop and going up an incline. Yesterday, I could barely make it up a hill while pulling out of an rv store. I may have found the problem though. The center clamp on my turbo was leaking and when the Cummins mechanic took the turbo off to change it, he found that it was severely worn. So today, it's getting a new turbo. Fun!

quote:

Originally posted by Gary Carter:

quote:

Rick

Richard you say you have a '94 which means that you should have the 6 speed transmission. This would also have the 230hp engine. If this is true you can pump out much more power, up to 400 but your transmission would not handle it. If you still have the 542 allison you need to keep it down to about 230hp.

Ok I have had close to 400hp out mine and that kinda scared me so backed it off. Was able to get almost 40 pounds of boost at that time. Just didn't know what would break first.

Anyway I have the banks split intake manifold and the larger banks waste gate turbo. Boost gage, and pirometer for exhaust temp. Changed the fuel plate in the pump and was still slow. Last I replaced the stock injectors with marine injectors.

Also replaced the 543 allison with a 2000 allison with lockup and overdrive.

And finally fuel econony increase about 1 mpg. But now I drive 65-70 at 16-18 hundred rpm. With a 3.73 rear end it is still a little pokey off the line but then anyone want to drag.

Hey Ed,

Up til recently, it worked great but I just found out my turbo was shot. It gets replaced today so I'll let you know what happens.
Thanks,
Rick

quote:

Originally posted by MWrench:
Richard, IIRC you have a 32' or 34' Breakaway, do you have 22.5 tires? If you do and you have the same diff ratio that I have, 4.1:1, it will be a real dog off the line! I know of one other longer Breakaway that has this combination and the trans doesn't shift into 6th until ~70 something, way to high gearing. Yours may be the same.

Mine shifts into 6th at 57-58, and with the new tires runs 2000 @ 70 MPH (lost about 50-60 RPM with the new tires) and even with this combination the initial acceleration is not great. Once it is in second and the boost is up ~20 lbs. it is OK.

Hi Rick, didn't understand that the sluggish response was a recent event. I will be very interested in what you find after the turbo is replaced. I would also like to know the turbo model and housing size that they are going to replace for comparison with what I have.

Although I can get good boost pressure ~20 lbs, it does take a while to get there from a standing start. With 142K mile on the clock, I have been considering replacing the turbo, but I don't like to fix what seems to be working. I have noticed on the last couple of trips that the response does change a bit but, I have to be careful judging because I am at all kinds of different altitudes and temperatures.

Thanks for the feedback!

The turbo was really interesting. It started out as my just needing the main clamp on the turbo replaced but when the mechanic put it on the bench, he immediately noticed that the blades were chipped. He refused to put it back on the engine.

To make matters worse, the Cummins replacement turbo had THE CLAMP ON THE REPLACEMENT TURBO BACKWARDS. So now, my Cummins dealer if fighting with the factory to get some labor taken off my bill.

I'm mo turbo expert but I am really glad I had the turbo examined because a blown turbo could have completely ruined the engine.

I wish I had the 230 with the 6 speed. Mine was originally 190hp and I pull a trailer loaded with dirt bikes and water etc. and it just wasn't enough. I did the banks stinger kit, new turbo (old one didn't spool up quickly). Now it has plenty of power, but I want to drive using 1/4 to 1/2 pedal instead of 1/2 to full so next i'm doing intake and exhaust as well as high performance injectors. The only thing i'm worried about is the 4 speed Allison and the rear maybe not being beefy enough for the extra hp. We estimate its around 240 now. I get 10mpg with the trailer...was getting 10 before without the trailer.

I hear you! I'm having the same problem! I noticed this post is about a month old. Do you mind sharing any advice you received that's not already posted on the forum?