Cummins 6CTA8.3 Modifications Beyond Pump Adjustments, Anybody Done Any?

[74M35A2]

I believe there are several various adjustments on our Bosch MW pumps for controlling fuel, but I'm curious as to if anybody has done any parts-changing for performance improvement on the Cummins 8.3L? Examples being governor springs, P style pump (any advantages, and front cover change to do it?), larger turbo (HX50 or Bat-Mo-Wheel'd OE turbo, or ?), removal of aftercooler (and install intercooler) or injector swap (marine or ?). If so, how did it work out?

Also, anybody jacked their injection timing up, say 19 degrees? I'm considering to do so, as I intend to run unloaded 99% of the time. I'm hearing the tools required to check and adjust this can be relatively expensive, therefore I may just have a Cummins wrench shop do it, as it may be less costly.

I'm considering to completely waste my tax return on a doing it all at once, and I'd like to hear some stories of those that have done so in parts or entirety themselves. Thanks.

 

[cumminsbandit]

Honestly, my truck would have 800hp if it had a good transmission in it... and i dont think its worth having the allison built to take it, because in the end its still just a slushbox. I'd just turn the fuel up a bit and wait till the day the tranny takes a dump. Then replace with a used one and repeat...

I would like to put a 5spd trans out of an old 5 ton in and 8.3 truck, or maybe a nv5600 2wd if possible some day... i have too many projects... huh

 

[HETvet]

There are a few stories of guys working them in OTR applications. Have heard about 550-600 horsepower but backed by a 10 speed transmission. NO personal experiencw

 

[Suprman]

Anyone know if HT740 bolt up to the 8.3? That would handle the added power.

 

[cumminsbandit]

Anyone know if HT740 bolt up to the 8.3? That would handle the added power.

bump

Someone must be able to tell us what can be hooked to what?

bell housing info needed!

 

[DWC]

bump!! ^^^

 

[nevrenufhp]

There are SAE adapters to go up or down a size. You would have to find an SAE#2 to a #1. There's a place in Phoenix that makes em still.

I have worked with a couple different guys on different builds. One (play toy)was going to run the 480hp injectors, 3k gov springs, and an HX55, and see how long the trans lasts.
The 2nd, a camper 923, has 3k gov springs, fuel nuts and top screw adjusted, straight pipe, and played with timing(not degreed in with tools).
The 3rd, (932 that still hauls) had the fuel nuts adjusted, 3k gov springs, and tried a 60mm compressor upgrade. Still has high EGT. Next mission is aftercooler. The stock water jacket intercooler just doesnt do it past around 275hp. Hopefully, I'll have my own 923/925 by the middle of next year. Then, I can do some R&D.

 

[MIDDLEMAN]

What kind of fuel mileage should a guy expect out of the 6CTA 8.3? I averaged about 6 on my long trip 1600 miles.But had high head winds. Its a 2008 dresser label on the engine and low hours I would guess since it was put in the truck. Looks like new when I peeked in the oil fill. I would like a pinch more power and better mileage. I have heard of 10-12 is possible? I am also think'n of going to the bigger 16.00 X 20 XZL's. Any suggestions? M925A2

 

[MtnSnow]

To get close to the 10-12 mpg you will be driving on the road at about 50-55 mph over 55 and the fuel gets drank faster. The increased un-sprung weight of 1600's will slow your acceleration as well as increase your stopping distances. If level ground is your primary driving then the 1600's might net you a small gain due to a lower engine speed but I have my doubts on that do to the extra work the truck will be doing to turn them.

 

[74M35A2]

Correct. Larger tires are the fast path to not achieving what you want. They will put a measurable kink in your fuel economy and available power. HD trannys are SAE orientated as stated above, so you can mix and match as much as you want. You can change flywheel housings or get adapters: http://garbee.net/~cabell/sae.htm