Cummins 8.3 Injectors

[freebirdbus]

Has anyone here used one of the diesel injector rebuilding services that claim power and fuel milage increases from their rebuilding/blueprinting of the injectors? I am interested in only hearing from those with first hand experience with one of these services. Thank you

[jimkate]

I have not used one of these services for injector rebuilding. However, I have rebuilt diesel engines for over 40 years, so I feel that I am qualified to voice an opinion.

I assume you're talking about the older C series mechanical 8.3 Cummins.

A fuel injector can only do two things. 1) it can open and close at a spring controlled, adjustable setting. 2)it can spray fuel quantity dependent on the size and number of nozzle orifices in the injector nozzle tip.

There is no way to 'blue print' a mechanical fuel injector to be any better than its original precision manufactured design.

If you are looking for horsepower increase, along with mileage, start with a bigger air intake system, a higher volume turbo charger, a boost fooler to allow turbo boost pressures to rise higher, a different cam plate for the fuel injection pump to increase fuel delivery, adjustment of the fuel injection pump star wheel for quicker throttle response, and larger turbo flow muffler for decreased exhaust back pressures.

Two good resources are TST products and Banks. They both have websites worth perusing.

[tylerdmoore]

My 2 cents...

I have owned 4, 5.9 Cummins in Dodge trucks. Each one I ran for over 200K miles. The last was a 2006. I had the injectors Honed by Dynamite Diesel in Monroe WA. I received a noticeable difference in torque and overall performance. I also logged a 2.8 MPG increase in fuel economy over the next 3 years that I owned the truck (pulling a 40' 18K horse trailer, coast to coast).

Granted, those results are not for the 8.3...but I will be going back to them to service my current 8.3 when the time comes for new injectors.

[sc3283]

Hot Rodders have thought "outside the box" for decades. That is why they can get more out of an engine than others can. Revisions and new concepts occur as well since manufacture dates of many items. Incorporating just the revisions or new concepts can make a difference by themselves. Then when the "outside of the box" thinking comes into play....increases in performance and or mpg can occur. Having been involved 1st hand with VW, and the GM 6.2 diesel (both mechanical systems) I agree with tyler...increases can be made.....I have seen it with both of the above products.
Even if no modifications are made....its a good chance pop off pressure, spray pattern could be off from new and a reputable repair facility can make the injector as it should have been new...which will make an overall increase.

[freebirdbus]

Jim, agreed with on most points, but Tyler's feedback is just what I was looking for. Thank you Tyler! sc3282, you hit the nail on the head. I have seen the value of that type of rework on gasoline fuel injectors. There is one shop that claims big improvements from adjusting (shimming?) the diesel injector spring pressure using old (used) springs because the new ones change and loose tension after they break-in. Anyone else that has swapped in 'blueprinted' injectors?
Thanks!

[timex]

I had a 1996 8.3 with mechanical fuel pump that I added a boost and exhaust temp gauge first. There were three adjustments to play with on the fuel pump. One is for RPM s which I left alone. One is for the amount of fuel to your engine. One restricts how fast it gets the fuel by waiting for turbo pressure to start to build. I added enough fuel to change boost from 20 lbs to 28 lbs. (Any more and the transmission wanted to slip when it shifted) Then I had to slow down how fast it got the fuel so it didn't smoke when you got on it. When your moving you have turbo pressure so you have good throttle response. It was good for one full gear on the hills going from 43 mph in fourth gear to 57 mph in fifth on a 29,000 lb coach. Had 87,000 miles on it with this setup. A good diesel shop should be able to fix you up.

[NHRA225]

Interesting thread ! I've never heard of any business "blueprinting" Diesel Fuel Injectors. Some call bluprinting- Cleaning and matching flows and spray patterns which is what I had done to mine when I installed a 150hp Fuel plate quite a few years ago. I was looking for more power while pulling my Trailer all over the Country.
My question is: what are you looking for and what objective are you trying to reach with a Blueprinted or modified Injector ?

[sc3283]

NHRA....what type race car & class?

How did your fuel plate work out for power and mpg?

[NHRA225]

S/Gas Beretta I race out of div 2 but live in Brownsburg In.
Fuel Plate: My 8.3C was rated at 300hp from Spartan and I needed or wanted more power to pull the Trailer. I installed the 150hp fuel plate kit from TST in Columbus Indiana and realized that these Guy's really know what their doing. No more Turbo lag at all and my MPG remains the same as long as I keep my lead foot out of it. I get about 8mpg @ 70 or 75 and 9 to 10mpg @ 60 or 65 and thats with the Trailer hanging on the back. In addition I removed the muffler and run straight pipes, TST also recomended that.
I see your SC is that a divisional number ?

[sc3283]

I've got a stock 8.3 in a 96 Dynasty. The # is my old # from years ago and yes a division 3 #

[tile man]

NHRA.. I have the same set up as you ( 95 american dream) and was thinking about the tst fuel plates as well. How much tourque gain did you get and what's the max for the md 3060?
Dan

[NHRA225]

These are the Fuel Plate Kits listed for the Mecanical 8.3.

TST has 4 power kits ($235 each mail order) that can be applied to the 8.3 6CTA engine:

Kit # Horsepower/ Torque Above Stock
#12 75 hp 150 torque
#08 100 200
#06 125 250
#05 150 300
I installed Kit #5 as recomended by the Engineers there, these Guy's are all retired from Cummins. Intallation was a breeze and the results are extremely favorable. I cruise at the speed limit and don't even know I've got a 10,000 lb trailer back there.
Climbing hills and grades is no longer a challenge. I did call Allison and they informed me that the additional Tq and Hp would not hinder my MD3060.
If your interested give them a call, at least just for the info.
( This is not an advertisment, just a satisfied Customer)

[wb6epp]

Somebody forgot to mention, that before all the other goodies are installed, your P-7100 pump needs to be advanced to 16.5 degree's, then all other will take hold in a hurry. My 1997 Dodge with 5.9 Cummins dyno'd out at 375 Hp with 850 torque. I pulled a 38 5th wheel with it. After increasing the timing I gained mileage from 17.8 mpg to 23/24 mpg empty. Towing it dropped to 12/13 mpg, but before mod's I was getting 8/9 mpg. your 8.3 can do better!!
Next, injectors are fine tuned!! That is the reason the shops use a flow bench to set the injectors to flow the same amount of fuel at it's pop-off pressure. Next I will say, if you do not advance timing and you throw in a "Fuel Plate" you are going to have black smoke like you won't believe until the turbo spools up.
Also, I forgot to mention, you can put in your P-7100 fuel delivery valves which supply more fuel to your injectors.
With the right mods, you can easily crank out 350 to 400 hp conservitly.
Yes, I spent 22 years in a shop. I qualify to work on all the older models, just not up on the new electronics.

[tile man]

nhra and wb,

Thanks for the info. I called allison and a local allison guy at cummins west and they said the md 3060 is rated at 310 hp and 950 #s torque. I have also heard they can handle 1200 #s torque?? I know alot of people have bumped up their motorhomes with banks or other without doing anything to the tranny.
I want to get a little extra power safely for towing, mountain driving etc., but am concerned about the tranny.