Torque/HP needed for towing @21,000#'s

[JAlford]

I have a new 5er, and Gross combined is 20,400#'s ready to go. 5er is 12'-6" tall and 30' long. My previous rig GCVW was 16,000. We did our first trip west with the new 5er last summer, and going out was an ordeal. My lift pump was failing. I am going back west this spring (new lift pump was installed during the last trip, many thanks to a fellow TDR member), and I am preping the truck. I haven't noticed a big jump in power, with the new pump (it is better). I couldn't stay in 5th when pulling grades, even on the return(post new pump). This limits me to 55-60mph, which in 75mph speed zones gets spooky and frustrating, with all the big rigs passing (even worse, the Fords and Chevys :{ ). I had the truck on the dyno when it was new, and it was 204hp at the wheels (before the mods). What HP and Torque should I spec parts to get to? Anyone doing this have a good guess? Or should I just start looking at FL60's?



Thanks for any input. I have rebuilt the 5spd, with all new components and fully splined mainshaft and cast iron tail, bronze syncs, and extra fluid cap. It still groans when I mash the pedal, but it has held O. K. so far.

Jeff

 

[Slow Six]

I am pulling a similar set up grossing a 1000 or so more. I had a BD torque plate, K&N filter and a full 4" exhaust on my 94. I forget the exact numbers but I think HP was around 300 and torque was somewhere around 600. I have the Edge EZ and AFE intake on my 03. Again approximate numbers are 360 HP and 650 torque. I was satisfied with both setups. I usually keep up or go by most big rigs on the hills unless they are unloaded. I am presently on an extended vacation. I travelled from home to Seattle and then down #1(west coast hiway) all the way to L. A. The truck has pulled and handled well on the whole trip. It can keep up on the freeways and does well on all the big climbs. I see you have an E-brake so I think if you turn your cummapart up a little you will be happy. A six speed would finish the package. A lot of the FL60,s aren't putting out any more than we are.

 

[juicedcummins]

You must have other problems. [maybe a boost leak] My 99 was about 2k heavier than you and it was only a 2500. It was an auto with 355's and 265/75/16 rubber.

If you went up one size turbo housing on your current turbo and say some rv injectors you would have it. Some say the 2's run cooler but I have never tried them.

 

[TRLRTRSH]

towing heavy

Jeff, we are towing about the same weight, I'm at 20,300#

but with an 03 3500 Auto, Last dyno was 355 RWHP, with the DD TTPM set on level 3.

I like the setup I have now, I hate slowing down going up grades, but do have to watch the temps



Bill

 

[RMcCulloch]

Jeff,



I'm pulling a bit more than you [23K gross - possibly a bit heavier ] with my bone-stock '03 305/555 and having no problems.



Since these engines are rather consistent at 245 HP to the ground, anything over that should make you very happy.

 

[DHawthorne]

I'm a little confused or I don't understand what your saying. Are you saying the Gross Combined weight of your truck and trailer is 20,300lbs? I would think that is what your saying with the trailer being 30ft long. Or, are you saying the trailer has a gross weight rating of 20,300lbs?



20,300lbs is the max recommended for my truck combined with the trailer weight and rear ratio. I have no mods other than a K&N air filter. My normal combined is 19,500lbs.



The best mod you could make as I should do, is change the rear to 4:10. I really don't turn enough RPM's in 6th gear at 65mph. It tows best a 70+ were the engine can breath better. 5th gear is not tall enough at 65 turning out 2500rpm. Best mileage towing for me when possible off the big road is at 55mph in 5th gear. Thats right at the rpm a 4:10 will give you in 6th. I'll average 13. 5-14mpg. In sixth at 65mph, 10mpg.



I may have gone off topic here not understanding what your looking for.



Dave

 

[EricBu12]

First you need a reliable fuel scource (Pump)... .



I replaced the stock lift pump and put a 7# pusher back by the tank... . Heres the set-up...



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The pre-filter before the Pusher is a 30 micron filter/water separator... this keeps the pumps clean... Then you need a Mechanical adjustable Regulator so you can set it for 14-15# This will give you better flow. The return of the regulator goes to the inlet of the prefilter so even the pusher don't have to work too hard... heres the regulator



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Heres the Racor filter... .



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Heres the Pusher Pump... the one-way check valve allows the pusher to work but in case it fails, the main pump can draw around the pusher and get home



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Now, then you need to put more fuel and Air in and more Air out... . A good quality Cleanable filter like K&N or others so it can breathe or the BHAF (big honkin' air filter) will do...



I have a Edge EZ box but a Edge comp or Edge Juice will do as well. I also Have an older 4-Wire Blue Chip box that adds 100 hp. Has 4 settings and I can turn it off. heres the Blue-chip...



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Now that you have fuel and air in, you need to get it out..... I have a 4" Straight through exhaust from Rip Rook with an Allied Truck muffler... Sounds great... . For the weight you are doing I would recomend you get the Jacobs E-brake... Made to work with the cummins ECM so no micro switches on the pedals just senses the Rpm's

Heres a Switch I bought to controll the on/off of the jake... .



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I have a 12' tall 5er too and I just got this deflector... See the new deflector thread in this area... but heres a pic...



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All these mods I have done gives me about 400hp and est 800 torque. I have a GCVW of around 23,000 and I have a 6 speed and I climb fairly steep hills at 55 or so... I have to watch the temps and not push too hard. . I have boost pressures of 30-35 psi and all this extra power helps the mileage... I get around 10 with this beast... .



Hope all this helps you in deciding what to do... .

Eric

 

[TRLRTRSH]

Gcvw

Truck and 5th wheel =20,300#



2003 "3500" CTD Auto, 373gears has a GCVWR of 21,000#



Bill

 

[DHawthorne]

He's got a 99, that has a combined, very close to my truck, of 20,300lbs. It could be less. He would be a good canidate for the insurance nazis if he got in a foul up on the hwy.



Dave

 

[JAlford]

Lots of good info! Thanks.

The GCCVW of the truck is listed at 21,000#'s, so I should be under the limit. I have some other issues with the truck that have to be addressed, but while I was having the injection pump checked and doing the valve adjustment, I thought it was a perfect time to upgrade. In order to pick out the best parts, I wanted to formulate an idea of where I needed to end up. Looks like around 350-400HP and 700-800ftlbs at the rear wheels would be close enough, from the earlier info. Changing the axles to 4:10 might be a good alternative, and I was looking at the overdrive box from US Gear also. Just can't stand being passed by a bunch of Powerstrokes/Duramax's!

Eric - your setup looks great! I have been looking at the FASS unit ever since the LP failed, so I might go that way instead. What injectors are you running?

Well, the bank account doesn't look safe for a while! :-laf Wonder if the Dana 80 can take the new upgrades?

Jeff