Haulin_in_Dixie

Towing and racing do share a lot of the same components but there is a large difference in what is needed. For instance I could not care less how long it takes my turbo to spool up, but once spooled I need the max boost and air flow for pulling hills and keeping EGT’s down. I have done a lot of reading from different sources on turbo size and have found this. Pulling Cummins ALWAYS recommend the largest turbo you can get with the largest outlet and exhaust diameter. Racing and hot-rod road driving is a different story. I have a couple of articles recommending the 16 cm housing for pulling. I realize that this is not good for ¼ mile and blowing the doors off rice burners. Without exception, any book or article from the Cummins builders all say the same thing, lower compression, more boost, larger exhaust and of course larger injectors. I was bothered by the fact that on this and other “SUV” boards this is not the route, leaving the smaller turbo outlet in place. See I am using my ISB as a big truck engine is used, not as a street machine. So experts out there, and we do have a bunch, I would like your comments on this subject. I do not really care how long the spoolup takes and racing a rice burner is not important in my case. I usually drive slow when not under a trailer and then run the hell out of it on the road near gross weight. Every bit of information I can get on building up a Cummins of any size for pulling loads up hills states that the larger turbo outlet is better for the engine and for pulling power. The important thing in my case is maintaining 70 to 73 up hills and on the flats with the minimum shifting possible while staying between 1900 and 2100 or 2200. When that becomes impossible I downshift (usually without losing spoolup) and keep it up above 2300. Converse to what I see on this board and others, I am considering the larger exhaust housing and 4 or 5" exhaust.

AlpineRAM

Hauling: I think you and the experts are right about using the bigger exhaust housing for a pure towing application. I think you should go for a bigger turbo like an HX40 with one of the bigger exhaust housings available, because if you operate a smaller compressor close to the end of its efficiency map it will increase intake air temperature. <br>For the normal acceleration junkie this combo would lag too much. <br><br>Just my 2c<br><br>AlpineRAM

Dieselbuilder

Always been a diesel fan (truck driver to many years) not a speed freak but like the fact you can hall 140,000lbs load up a 12 percent at 50 ,TORQUE IS WHERE IT'S AT ;D

Haulin_in_Dixie

[quote author=Dieselbuilder link=board=4;threadid=17206;start=0#161147 date=1058482873]<br>Always been a diesel fan (truck driver to many years) not a speed freak but like the fact you can hall 140,000lbs load up a 12 percent at 50 ,TORQUE IS WHERE IT'S AT ;D<br>[/quote]<br><br>Happiness is watching the expression of the '03 Ford 6.0 while passing him on a hill

wannadiesel

I am not an expert, but I agree that you'll see lower EGT's at high load with a bigger turbine housing. This is assuming that the bigger housing is capable of spinning the turbo fast enough to make enough boost for your fuel. I think you will pick up a little fuel economy by doing this, too. Lowering the drive pressure while keeping adequate boost will make the engine more efficient. I've read on other boards that 1st gen guys who put 12 and 14 cm non-wastegated housings on lost a couple mpg on the highway, so the reverse should be true for you. I'd bet you can get 18 and 21 cm non-wastegated housings for free to try (once I get my 12 cm wastegated one on, you can have the old one if you want it). The only things that would concern me would be smoke and EGT at lower RPM.

Bart Timothy

I think it all depends on where you're towing. In higher elevations on twisting mountain roads a smaller, faster spooling turbo is better. Try pulling a heavy TT through Yellowstone with a large turbo and you'll see what I mean.

hellotbone

Something around a PDR 40 or B1KS should be what you are looking for.

KATOOM

What is expected in loss of boost or gain in EGT's with increase in altitude? Is there a ratio?

Push Rod

Bill,<br><br>You've almost got it nailed with your comment about the largest turbo you can spool being the best in your application. Tie it in with Bart's comment about the turbo needing to spool properly at higher elevations, and you've got it. You don't need as much spoolup as a racer, but you still need decent spoolup.<br><br>We've got several hotshotters out there who are pulling some pretty good weights with an HX35/16, however they are still running awful warm (1200 - 1250F) so I believe that the compressor just can't deliver enough air for the heavier weights. I think if I were you, with your power level, I'd look to a hybrid HX40/HX35, probably with a 12cm or 14cm housing. You'll have a bigger compressor to drive more air, and the tighter housing will keep it spooling better in higher elevations. You'll definitely want the 4 inch exhaust as well.<br><br>Rod

Haulin_in_Dixie

I want to thank everyone for the info and opinions on the turbo subject. Also I just found this on the BD site thought it might interest some.<br><br><br>1989-1993 Cummins 5.9 engines have a variety of large turbine housings that all result in a large turbo lag before boost is developed<br><br>All the above years will benefit by changing to a 16 sq cm housing to a non-waste gated turbine housing part #1045910 on stock or engines that have had high flow injectors installed<br><br>1994-1999 stock engines have the 12 sq cm w/g hsg that can be quite restrictive when the power is increased above 300 flywheel HP and results in high exhaust temperature. Changing to the 14 sq cm w/g turbine hsg # 1045920 or the 16-non/w/g hsg #1045910 will reduce temperature and improve engine power.<br><br>2001 automatic transmission equipped engines have a 9 or 10 sq cm hsg that is too restrictive for a high power increase (beyond the 300 hp) and should have our new HX35 Super Turbo installed. <br><br>

gunracer1

i hit 20 mpg for the first time after i swapped to a 14 cm wg housing on my truck [pretty good for a 4x4 dually]. it was well worth the time to install it. plus i have much more top end. it should work great with a good exhaust.unless you go pretty wild, i think the 35 will work like a champ for you. mike