12 Valve Conversion Help & Tips???
 

Hey guys. I'm doing a Cummins swap into my 1980 Powerwagon that has 12" of lift on it with 40" Boggers. The entire suspension and diffs are built with Yukon Chrome moly shafts, CTM u-joints and Detroit lockers. My old 360 is way too tired and I'm putting in a good ol' 89 Cummins. The only problem is that I have NO experience with the first gen 12 valves. I am used to the VP trucks and the CR trucks. Can someone point me in the right direction with power upgrades??? Will I be OK with the truck not being intercooled for offroading. That's all this truck does is offroad through huge mudbogs, through the bush and so on. Tater, got any tips????

Thanks for any tips or suggestions guys....:cool::cool:

what kind of power do want ?????????? do u want fuel mileage ?????? do u want smoke ??????????? ... i have been playing with these trucks for a few years ,,, they turn on very esay and fairly cheap.... and is it auto or standard ??????????????????????????....

the things i would start with

hx 35
3000rpm spring
unhock the afc
lift pump up grade
fuel screw 1/2 turn off runaway
big exhaust like 5 inch
make sure u are getting full thro

Purely offroad. Want good bottom end and it's an automatic that was just rebuilt. Thanks man...:cool:

dont get crazy fuel without an intercooler.

Yup also with an 89 engine, EGT's are a concern not only due to lack of intercooler but due to cracking the head. The 89-91.5 engines utilize 9mm injector nozzles and the material between the exhaust valve and injector port is quite small. You keep the fuel in check and it should be OK.

In my 89 I had the 180 Hp injectors, stock turbo and 3.5" exhaust (pillaged from a Bank$ Ford pipe setup as 4" wasn't available then). With just those injectors, tweaking the throttle linkage (instead of the governor spring) and not touching the fuel screw was about the limit. My 93 I went without the injectors and just maxed out the pump and got a Dyno of 268RWHP with it.

If I can muster some time, I would love to stop by for a peek.

I uploaded some photos of my old rides to my gallery..:cool:

i no a guy running 350 hp nonic ... but a cooler is a good idea but not a most . the 1st gen can run hot then other cummins say 1200-1350 all day long .new ones 1100.. the big exhaust helps alot , my egt went down almost 400 when i put it on

That's sounds great J..

Too big of an exhaust, won't that cause bottom end loss??

leave the down pipe 3".. thats what i did. and i gained power ,,,

the answer to that is no.



anything after the turbocharger is as low of backpressure as possible. cummins only list a maximum spec for BP in the exhaust, on the big QSKs anyways, and its VERY little allowed. so no, you can't have too big of an exhaust. thats naturally aspirated gasspot talk going through your head. shake it out [laugh]

AND there is the answer thought is what i thought but i was not sure so i left for some that no's like luke

that being said, it has been proven over and over, that in reality anything bigger than 4 " is just for show,, that is all that is on my truck is a 4"

Kevin

isn't 5 inch a benificial after 600hp?

Good one Luke..[laugh][laugh]

That should be a sweet rig. I love the old body style....I have an '80 W200 sitting outside the house right now that I use for a knockaround/yard truck. 440/NP435-could use a 205 swap in place of the 208 that's in it now but that's a project for another time. This summer I was trying to find a Crew Cab long box to swap a CTD into-but I kinda let that one slip to the backburner for now. Went on a parts-truck acquiring spree in anticipation of it though-there are 3 '80s and a '77 sitting waiting to donate....

I would think a swap to a wastegated turbo ala HX35 should help the bottom end a ton by getting the boost/fuel going quicker. I'm with the others about keeping the fuel in check without an aftercooler though. Maybe a good time to add one? Thought I read somewhere about a PSD aftercooler being used as a 1st gen upgrade. Should be able to find one of them kicking around from a dead one-god knows there's lots matching that description. :cool:

Jason