Duramax/cummins conversions?

[Edahall]

Originally Posted by Skunksmash

What's the most horsepower that you can make with a 12 valve and not hurt fuel economy. Only thing that concerns me about the 12 valve cummins is they're what... 150hp stock? If I ever considered the swap, I really wouldn't want to go DOWN in hp lol. Down from my 350's already low factory 220hp, to 150hp... I don't think I could bring myself to do it.

Increasing horsepower doesn't necessarily decrease fuel economy if driven in the same manner. More often than not, it increases fuel economy.

The 1st generation 12 valve was rated at a conservative 160 hp. However, it actually put out quite a bit more than that. Even in stock form, they'll pull harder than a 454 big block. One big reason for the very conservative horsepower rating was because the rest of the Dodge truck (such as the transmission) couldn't handle more than that. That said, it is quite easily to get 300 hp out of these engines with just some simple adjustments. After that, it'll require different turbos, etc. The VE injection pump is limited to about 450 hp max.

The 2nd generation 12 valve with the P-pump is a different animal in terms of power. These suckers can put out over 1000 hp without too much difficulty. Everybody wants these engines for the big power so they cost more money on the used market.

[84chevyguyid]

The 160 horsepower might not sound like much but its the torque that moves the load. 250 hp might net you 600 ft lbs of torque, your 350 wont even have half that.

[Skunksmash]

Originally Posted by Edahall

Increasing horsepower doesn't necessarily decrease fuel economy if driven in the same manner. More often than not, it increases fuel economy.

The 1st generation 12 valve was rated at a conservative 160 hp. However, it actually put out quite a bit more than that. Even in stock form, they'll pull harder than a 454 big block. One big reason for the very conservative horsepower rating was because the rest of the Dodge truck (such as the transmission) couldn't handle more than that. That said, it is quite easily to get 300 hp out of these engines with just some simple adjustments. After that, it'll require different turbos, etc. The VE injection pump is limited to about 450 hp max.

The 2nd generation 12 valve with the P-pump is a different animal in terms of power. These suckers can put out over 1000 hp without too much difficulty. Everybody wants these engines for the big power so they cost more money on the used market.

Thanks for the good explanation. I'd like to get your reply to the same question, only for the 4bt instead.

My concern about HP was related to highway speeds, though from your answer it looks like it wouldn't really matter. I was wondering if 160hp would be good enough to put the pedal to the metal and be able to weave in and out of traffic. If necessary.

[andrewmp6]

A 4bt is 105hp and 265 foot pounds of torque.You can build up the 4bt to make more power the max it can do safely is around 400 to 500hp and pushing 800 foot pounds.If you want something to read http://www.competitiondiesel.com/for...d.php?t=119216 That site is more people building big power but they have a ton of useful info tho.

[ssapach]

Originally Posted by rs74

Yes PPE is one of them and then there is this company. I have been thinking about this conversion in my K30.

http://www.btdieselworks.com/product...wiring-harness

Good to know, thanks!

I've been keeping the thought of a D-max swap in the back of my mind for a while now. Just need to get super ambitious or else annoyed enough that I can't get a new truck the way I want it.

[Edahall]

Originally Posted by Skunksmash

Thanks for the good explanation. I'd like to get your reply to the same question, only for the 4bt instead.

My concern about HP was related to highway speeds, though from your answer it looks like it wouldn't really matter. I was wondering if 160hp would be good enough to put the pedal to the metal and be able to weave in and out of traffic. If necessary.

The 4bt has the same stroke as the 6bt but has 2 cylinders shaved off. It'll behave very similar to the 6bt but have less power potential. I hope you know that the 4bt is a very loud and rattly engine.

160 hp on a Cummins would feel a lot more powerful than 160 hp on a gas engine. Why? Because the 160 hp on the Cummins would be all there at cruising rpm's but on a gas engine, you have to downshift to be able to use that power. In a nutshell, a Cummins puts out a lot more power at cruising rpm's (such as 1600 rpm's) than a gas engine.

As I mentioned previously, these engines don't take much to make significantly more power. It was like they were dumbed down to protect whatever was behind it.

[customisaak]

some good info on the standalone mod. i have been looking for more info as well. I was planning a 12 valve swap but i picked up a 2006 duramax, complete and cheap after one of the guys at work put it on its side. Its going in my 1980 4x4 crew cab. I want to use as much of the '06 as i can.

[nekkidhillbilly]

alot of bad duramax info here no offense to anyone. only lb7s have injector problems. duramaxes pull the best mpg from what ive seen in comparisions prior to the emissions garbage with the lmm. the lb7 has a 100 less hp and 100 less ft of tq than the lbz 50 less than the lly. no way a lb7 will run circles around a lb7 or lly ive driven all 3 without some serious mods. there are some llys with 800k. there a solid motor. the rest of the truck they come in stock i own one hate that truck love the engine and trans though. cummins is a great platform also. and only the early 24v had the head problems. the 01s for example were solid. we are about 300k on the one we have.

86 Chevy crew cab 4x4 LB7 Duramax swap - YouTube

it has been done. ive talked to this guy about this it was simple swap he just used a ford dana for the left side drop to match with the transfercase from the dmax. im going to build one when i get my house done similar. all should be the same the only thing if you want say tap shift tow haul mode or od lockout you need to add the bcm from a wreck dmax to control all that. if you dont its not a hard swap after ppe mods your harness. it is double a cummns in cost however but you do get a quite better trans. adding a allison to a cummins though is just as costly if not more. you can also buy the alldata wiring diagrams and mod your own harness. lastly no way i would do a square body on a 01 up frame. the sfa in the squares and even the ifs on the 2wds is a quite more solid front end. the new trucks have the worst front end on them and the brakes are junk. i have went through pitmans idlers wheel bearings and so on countless times and i cant keep brakes on it. i would do a body swap on a dodge or 7.3 ford first. (i wouldnt touch any other psd with a 10 foot pole.)