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12v Cummins mild build

7K views 28 replies 13 participants last post by  Fire god 
#1 ·
Hello, I have a 1997 12v that I'm looking to wake up a little. I'm getting a borg Warner k27 that's rated for 450 hp. I'm going to get 4k springs, and the like, but I'm wondering what injectors would be the best for around that 400-425 range(also anything else that should be changed at the same time as the injectors). I'm looking to keep some fuel economy, be able to smoke a little, and have considerably more power. Thanks
 
#2 ·
Heartfelt Advise Appreciated



How about you give us some information in order to be able to help you, like a sig.
Tranny type? Gauges? KDP taken care of?
If an auto tranny, best take care of that first.
 
#3 ·
Hello, I have a 1997 12v that I'm looking to wake up a little. I'm getting a borg Warner k27 that's rated for 450 hp. I'm going to get 4k springs, and the like, but I'm wondering what injectors would be the best for around that 400-425 range(also anything else that should be changed at the same time as the injectors). I'm looking to keep some fuel economy, be able to smoke a little, and have considerably more power. Thanks
How about you give us some information in order to be able to help you, like a sig.
Tranny type? Gauges? KDP taken care of?
If an auto tranny, best take care of that first.
Okay. I have a 5speed nv4500 with only 128000 miles on it, and those were all easy miles. So tranny is good. Gauges. I don't currently have any gauges, but I am getting them. What would you recommend? And kdp is the first thing that I took care of. (Damn thing already fell out 🤣 miracle that it didn't hurt anything) I've done the fuel plate mod, and a five inch straight pipe, and South bend dual disc. I was thinking about doing the 450 hp kit from powerdriven diesel, but i don't know if I need all of the stuff they're offering with it.
 
#4 ·
I'm looking to keep some fuel economy, be able to smoke a little, and have considerably more power.
Why would you like to be able to "smoke a little" Is it some kind of chest puffing thing where you live? Diesel pickups belching smoke give all of us a bad name. Apparently you are not aware that smoke is unburned fuel. Wouldn't it stand to reason that if the engine is smoking you are wasting fuel? How do you waste fuel and keep fuel economy?
 
#5 ·
I'm looking to keep some fuel economy, be able to smoke a little, and have considerably more power.
Why would you like to be able to "smoke a little" Is it some kind of chest puffing thing where you live? Diesel pickups belching smoke give all of us a bad name. Apparently you are not aware that smoke is unburned fuel. Wouldn't it stand to reason that if the engine is smoking you are wasting fuel? How do you waste fuel and keep fuel economy?
Wow ok, distort what I said. Thanks for being condescending. Maybe it is some sort of chest puffing thing we're I come from. But is that a big deal? No. And I only said "a little." Not belching smoke. I just asked what professionals would recommend for my truck since I am a newb to Cummins. I didn't ask to be judged.
 
#6 ·
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#7 ·
Professionals recommend you tune your truck to run strong and clean.

A lot of valuable information can be gleaned from forums like this, but one trade-off is you don't get to dictate the replies you receive. You won't get on good terms with anyone here by going after a smoke show. It's okay though, the learning curve is something everyone has to deal with.

5x12 injectors pair nicely with a K27.
 
#9 ·
Don't sweat it bro.
Just realize that it's not ideal to run around smoking.
 
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#12 ·
I'm looking to keep some fuel economy
This is mostly about being able to keep your foot out of it, rather than your injectors/turbo/whatnot (of course, a bad tune is a bad tune). Not always easy when you've got it all turned up :)
 
#13 ·
I'm looking to keep some fuel economy
This is mostly about being able to keep your foot out of it, rather than your injectors/turbo/whatnot (of course, a bad tune is a bad tune). Not always easy when you've got it all turned up <img src="http://www.cumminsforum.com/forum/images/smilies/smile.gif" border="0" alt="" title="Smile" class="inlineimg" />
I know, lol. It's not my main truck. I have an lbz Duramax that I have for long trips. This is just my mess around beater but a little fuel economy can't hurt. Lol
 
#14 ·
As mentioned, 5x12's are more than enough for 450hp. Bump your timing to 20* and throw on a new head gasket and studs. Throw your fuel plate in the trash and put a 2095 rack plug in. Put a fuel tank sump kit on and run 1/2" lines straight to a modified lift pump (PDD has a decent one I am making about 700hp with) and delete the fuel heater, throw it in the trash. Also, take your grid heater out and throw it in the trash. Then, sell your LBZ.
 
#15 ·
Pollution Porn is awesome. #visiblehorsepower


QUOTE=2000ram12v;29098943]
I'm looking to keep some fuel economy
This is mostly about being able to keep your foot out of it, rather than your injectors/turbo/whatnot (of course, a bad tune is a bad tune). Not always easy when you've got it all turned up <img src="http://www.cumminsforum.com/forum/images/smilies/smile.gif" border="0" alt="" title="Smile" class="inlineimg" />
I know, lol. It's not my main truck. I have an lbz Duramax that I have for long trips. This is just my mess around beater but a little fuel economy can't hurt. Lol[/QUOTE]
 
#16 ·
I rolled coal with my entirely stock 1997 automatic. It only happened one time and it surprised me. I took off hard and saw smoke in the rear view.

Your 5 speed will need a new clutch assembly to handle the extra power.

Any time you add extra power you decrease MPG. I want to get 20 mpg locally from my rig. So far I have been unable to beat 19.9 mpg.
 
#20 ·
Any time you add extra power you decrease MPG.
Not necessarily. It's using the extra fuel that results in lower mileage. My truck gets as good now as it ever did just going down the freeway with the cruise engaged. 20+ is easy if I stay below 65, and that's with the lower O/D ratio of the G56. I'm at 2200 rpm at 65 mph.
 
#17 ·
Lol.

Tape an egg to your accelerator pedal and try not to crack it. You'll hit that elusive 20.
 
#19 ·
I already accelerated very slowly. I suspect taking 2 rear tires off the dually might make the difference.

An aftermarket tc made a huge difference. It moves instead of thinking about it like it did with the factory tc.
 
#23 ·
Yep for real. And that is with max fuel. I have found turning down my fuel does nothing for my fuel mileage. I run it maxed all the time and just control it with the pedal. Been doing this since my first 12v in 2008 and it hasn't proved me wrong yet
 
#27 ·
Totally believable as I can easily get over 20+mpg with my 12v at 700hp. Build with the right parts, 18 degs timing, run 5-6psi @ 525degs at 3500-4000ft @ 60-70mph & drive with 33" mud tires & don't drive like an idiot all the time. Many run too big of tire & too much boost....both kill fuel mileage.
 
#24 ·
Wow, my truck gets 14 MPG on a good tank, but perhaps the 37 inch tires and frequent stop and go driving isn't helping the MPG cause.
 
#25 ·
14 is horrible for a 12v. If you are running the stock speed sensor you need to multiply your miles driven by 1.21 (30.6/37) to get your actual miles you went on that tank.
 
#26 ·
I used a GPS based app for a couple tanks and it showed about a 1/2 MPG better than the dash trip odometer calculation. My 12v isn't my daily driver, so I quite using the GPS for it. So I'm still in the 14 mpg range.
 
#28 ·
Yep I am at 19* and my twin setup is boosting about 8psi on flat ground at 70mph with EGTs about 750. I am on 33" tires as well with an NV4500 and 3.54. Cool, boosted, and rocking a sick azz truck.
 
#29 ·
That's the ticket.
 
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