So who has bumped the power on a 6CTA cummins

[74M35A2]

Hey nevr, I think you list marine injectors for sale, and I'd be up to a marketing trade. Donate the marine injectors, and I'll install them in my M925A2 and post timed performance run results, back-to-back done on the same section of road. Diesel performance sites shun using marines in non-marine engines due to producing a smoke haze and incorrect spray pattern for the non-marine piston (potential cylinder wall washing?), yet I wonder if there is any truth in that.

What would the difference be between turning up an MW pump, and changing injectors? I would think if one turns their MW pump up to the recommended safe 1250F max limit, then adding even more fuel via marine or larger injectors, or using a P7100 pump, could not yield further benefit, it would just drive the temperature higher. Disclaimer, I have yet to fully understand the correlation here. Obviously adding more air allows one to add even yet more fuel. Am I wrong in assuming that you would eventually change over to a P7100 and/or different injectors once the MW fuel rate can not be turned up any further? I'm guessing that is the correct path, and at that point, ditch the coolant filled, restrictive engine mounted aftercooler, and change over to a radiator mounted air-to-air intercooler.

I actually also want to quantify the air cleaner modification. Idea is to put a precision vacuum gauge and recording equipment on my 9 by using a car MAP sensor, and then record the highest level of vacuum trying several different air mods, such as removing the intake mushroom and the top of the inlet snorkel, run with no air filter, run with stock air filter, and run with the slightly smaller diameter air filter that appears would allow full usage of the filter element. Then we will know where the bottlenecks are.

 

[nevrenufhp]

Hey nevr, I think you list marine injectors for sale, and I'd be up to a marketing trade. Donate the marine injectors, and I'll install them in my M925A2 and post timed performance run results, back-to-back done on the same section of road. Diesel performance sites shun using marines in non-marine engines due to producing a smoke haze and incorrect spray pattern for the non-marine piston (potential cylinder wall washing?), yet I wonder if there is any truth in that.

What would the difference be between turning up an MW pump, and changing injectors? I would think if one turns their MW pump up to the recommended safe 1250F max limit, then adding even more fuel via marine or larger injectors, or using a P7100 pump, could not yield further benefit, it would just drive the temperature higher. Disclaimer, I have yet to fully understand the correlation here. Obviously adding more air allows one to add even yet more fuel. Am I wrong in assuming that you would eventually change over to a P7100 and/or different injectors once the MW fuel rate can not be turned up any further? I'm guessing that is the correct path, and at that point, ditch the coolant filled, restrictive engine mounted aftercooler, and change over to a radiator mounted air-to-air intercooler.

I actually also want to quantify the air cleaner modification. Idea is to put a precision vacuum gauge and recording equipment on my 9 by using a car MAP sensor, and then record the highest level of vacuum trying several different air mods, such as removing the intake mushroom and the top of the inlet snorkel, run with no air filter, run with stock air filter, and run with the slightly smaller diameter air filter that appears would allow full usage of the filter element. Then we will know where the bottlenecks are.

The air filter tests have been done. The conclusion was the size of the air filter (needs more surface area).
I can't afford to give out a set of those. I barely break even when I do sell em.
Differences in power: upping the fuel adjustment, about 270hp. Adding marine injectors on no pump adjustments, around 340hp. Marine injectors with pump adjustments, about 400hp. Swapping to a Ppump (with fuel adjustment) with marine injectors, 500-540hp.
Yes, when you add fuel, the turbo can keep up pretty good. Once you add the big injectors, it will need a turbo that can put out the air to keep it cool. HX50 will barely do it, but be ok in town if the truck is unloaded.

 

[Ford Mechanic]

Hey nevrenufhp, where were those air filter results at? I must have missed them. I was looking at installing that smaller air filter kit that one of our members sells. I thought it showed more cfm than stock? Maybe I misread. Do you have a better solution to the stock restrictive air filter?

 

[nevrenufhp]

It wasn't posted here, I don't believe. The owner of the 923 that I took the videos of (many pages back on this thread) is the one that did the testing. I don't have access to one here to play with and experiment on. My concept is to use a bigger intake tube, and use a big rig filter and housing.

 

[74M35A2]

So, when does one change to larger injectors? When turning up a pump further does not yield increased performance results? I have yet to learn the relationship of turning up a pump vs increasing injector size.

 

[nevrenufhp]

So, when does one change to larger injectors? When turning up a pump further does not yield increased performance results? I have yet to learn the relationship of turning up a pump vs increasing injector size.

Yes, go with bigger injectors if you aren't satisfied with the freebie adjustment, or you want to start with big power.
just adding marine injectors will get some pretty good gains if you don't want to mess with the pump.

 

[Csm Davis]

So a set of marine injectors, what size, and do you have to change the turbo or can that wait until you bump the pump?

 

[nevrenufhp]

If you watch the pyrometer you can get the hang of how long you can keep your foot in it. It's still risky, even if you don't mess with the pump adjustments. The marine injectors are big, and I don't have the hole size specs besides they are 5 hole and for a 480 hp 8.3. That's 480 with a 12mm Ppump.

 

[Ford Mechanic]

If I do the full fuel adjustment on the rear of the pump will I have to re-tune the pump?

 

[nevrenufhp]

If I do the full fuel adjustment on the rear of the pump will I have to re-tune the pump?

Depends on the tuning you're talking about. The screw on top will have a little less effect, and the AFC adjustments shouldnt need anything.

 

[Ford Mechanic]

Just what can I expect by doing the full fuel adjustment?

 

[nevrenufhp]

A gain of about 40hp.

 

[adeso]

So after reading *most* of the 40 pages, I have a few questions and observations. I will hopefully own one of these soon and I want to be able to have it run well both empty and still tow (I understand duty cycle and the fact if you use all of the go petal towing you will break stuff). My last project was a high power duramax that was on 35s and still towed equipment, but would put about 850 HP to the ground. Most of my work has been with common rails so these dinosaurs are new to me.
1. What is the limit on the trans? What goes first, slipping the TC, burning out one of the clutch packs? Breaking a part?
2. How about the Tcase? It seems from what I have read to be more of an issue in reverse so it the way it is mounted that is the issue?
3. How robust is the cold side of the turbo? Can it take a twin turbo without blowing out hoses or the IC?
4. How good is the stock IC at heat transfer? I plan on putting it on its own coolant system but would I benefit from an add on air to water cooler if I run a twin setup?
5. For guys looking at putting an aux cooler for the air to water cooler, I would recommend mounting it somewhere not in the front stack with the radiator. One of the things we have found with the high HP pickups is with the IC, trans cooler etc up front the air is already over 200*F by the time it gets to the radiator under a full load. Which is fine for a pulling truck or race truck that only sees that for 30-45 seconds at at time but will hurt the continuous duty cycle a lot.
6. How is the oil cooling system on these trucks? I found that adding oil only cooled turbos on my truck caused issues and I had to add an aux cooler, has anyone ran a oil temp gauge on these trucks?
7. Why are guys running these engines up to 3200 RPM? does the fuel pump add in timing based on RPM? if not it seems like a waste to run it up that high other than to get top end speed due to the trans.
8. Does this engine use the same mounting as a 5.9 for the injector pump? What other parts are the same as the 5.9?
9. How is the turbo waste gated, and what flange size does it use?

Thanks in advance for the info!

Andy

 

[FullSpecial]

Only thing I can answer is #9. There is no waist gate. The snorkel piping and air filter are so restrictive
it is not needed because it can't make enough boost to worry about. Now if I can just get my boost gage working.......

 

[adeso]

Only thing I can answer is #9. There is no waist gate. The snorkel piping and air filter are so restrictive
it is not needed because it can't make enough boost to worry about. Now if I can just get my boost gage working.......

That is interesting. I it would worry me to start turning the fuel up too much like that and over speed that turbo/ just add a lot of heat to the system. Esp if it is starving for air.

With me being lazy and not looking for it does anyone know what the specs are on this turbo?

I found the answer to my question, a Hx40.
I think it needs a big brother like a S475

Edit, after looking up the specs on this turbo (58mm inducer) and a fairly open turbine they seem to be good for about 350HP non gated and 400 or so gated. I would still want to get ride of the restriction on the intake side since that tends to overspeed them. The turbo seems to be a somewhat standard 3.5 ratio compressor map so I would think low to mid 30s on the PSI at sea level would be fine for them.

 

[VPed]

#2: The problem with the tcase and reverse is not about the mounting of the tcase. It is about the wicked low reverse gear in the Allison. Coupled with the tcase in low gear, the torque exceeds the strength of the case. I imagine that if you make enough engine torque with performance upgrades, you will find the tcase limit even when in high range or forward gears.

 

[adeso]

#2: The problem with the tcase and reverse is not about the mounting of the tcase. It is about the wicked low reverse gear in the Allison. Coupled with the tcase in low gear, the torque exceeds the strength of the case. I imagine that if you make enough engine torque with performance upgrades, you will find the tcase limit even when in high range or forward gears.

And it is the case that is splitting and not something inside letting go? Anyone know if the break in the same place? If so I'm thinking maybe it will live longer if it is braced.

And thanks for all the info guys. I know I'm planning on taking the truck well outside of its design limits in some areas.

 

[nevrenufhp]

#1, 270hp/700tq. Last one I killed was the converter slipping, but was making a little more than that spec. Internal clutch slippage also can happen. With the torque curve moved up in the rpm (timing advanced), then there is less low rpm torque damage.
3. The turbo is good. HX40 can take a good amount. A big brother would help a bunch....if you could feed it enuf air.

7. You can run it to 3200, not to say it's necessary. That way it doesn't start defueling at 2300. Nice, broad power range. No timing advance unit on these pumps.
8. The mount is similar to a Ppump. Not much swaps across between them. Gov springs and possibly delivery valves is about it.

 

[74M35A2]

So after reading *most* of the 40 pages, I have a few questions and observations. I will hopefully own one of these soon and I want to be able to have it run well both empty and still tow (I understand duty cycle and the fact if you use all of the go petal towing you will break stuff). My last project was a high power duramax that was on 35s and still towed equipment, but would put about 850 HP to the ground. Most of my work has been with common rails so these dinosaurs are new to me.
1. What is the limit on the trans? What goes first, slipping the TC, burning out one of the clutch packs? Breaking a part?
2. How about the Tcase? It seems from what I have read to be more of an issue in reverse so it the way it is mounted that is the issue?
3. How robust is the cold side of the turbo? Can it take a twin turbo without blowing out hoses or the IC?
4. How good is the stock IC at heat transfer? I plan on putting it on its own coolant system but would I benefit from an add on air to water cooler if I run a twin setup?
5. For guys looking at putting an aux cooler for the air to water cooler, I would recommend mounting it somewhere not in the front stack with the radiator. One of the things we have found with the high HP pickups is with the IC, trans cooler etc up front the air is already over 200*F by the time it gets to the radiator under a full load. Which is fine for a pulling truck or race truck that only sees that for 30-45 seconds at at time but will hurt the continuous duty cycle a lot.
6. How is the oil cooling system on these trucks? I found that adding oil only cooled turbos on my truck caused issues and I had to add an aux cooler, has anyone ran a oil temp gauge on these trucks?
7. Why are guys running these engines up to 3200 RPM? does the fuel pump add in timing based on RPM? if not it seems like a waste to run it up that high other than to get top end speed due to the trans.
8. Does this engine use the same mounting as a 5.9 for the injector pump? What other parts are the same as the 5.9?
9. How is the turbo waste gated, and what flange size does it use?

Thanks in advance for the info!

Andy

That is a lot of questions for a new guy just pulling up a chair to the table. You can find a lot of this info yourself, just as I did when I first bought my 925A2 (8.3L). For example, look up what trans your truck has (Allison 5 speed MT654CR), then check the online specifications for that trans. Doing so is actually good in that it removes a lot of opinions and armchair quarterbacks.

From what I have seen, not many people have increased power of their 8.3 beyond fuel rate increases, so expect limited responses from here. From my research, about all of your questions are maybe best answered on a tractor pulling website, as this engine is used there where they turn them up way more than we do. You should have more access and knowledge to diesel performance sites than most all of us combined if your stated claims hold water.

To help a little, some people add aftermarket governor springs (GSK) to increase RPM for firmer shifts and to increase top speed which is otherwise gear/governor limited to about 65mph on an M939A2 series. Once you exceed 55mph, which is the tire rating, a lot of people here will start jumping up and down about safety and liability.

I believe a Bosch P7100 pump, as more commonly found on the 5.9L's, will mount and work in place of the Bosch MW pumps as equipped, but there is a difference in the oil supply/return line being internal vs external? I'm not sure, but something along those lines of compatibility. An injection shop dealing with agricultural engines would know much better.

The turbo is usually a Holset HX40, which by most standards is a T4 mount flange.

The rest of your questions have too much variability to answer as a one-liner. Trans durability for example, depends on shock load, temp, duty cycle, gear ratio, tire size, mass of vehicle, etc..... For the rest, please keep us updated as you do the mods, so we can all learn something.

 

[mike_belben]

... I discovered after several months of adjustments and looking/investigating fuel/power issues on ours the short metal line coming from the intake manifold to the little tin cover on the back of the pump is for the ratio valve.

i dont think theres a such thing as a "ratio valve" in american injection pump speak. thats the boost signal to the AFC aneroid. boost presure fills the aneroid cavity and acts against the diaphragm which creates a linear mechanical motion that compresses the AFC spring (which is preloaded by the starwheel, thats just an adjustable spring seat.)

boost into the AFC is what releases some early rack travel during initial takeoff from low RPM/no boost conditions.

at the other end of the rpm spectrum is the governor, which pulls rack travel to regulate max RPM. pretty much all there is to it.