An easier way to turbo an M800 truck

[JasonS]

I know that the title is a big claim but I really do think that this worked out well.

1. I used of a factory Cummins crossover tube (142248 ) and intake manifold. This particular intake retains the flame heater. While the turbo outlet and crossover inlet don't exactly line up this is easily fixed with two 23 degree silicone elbows and an inline coupling between the two.
2. I initially tried to simply bend the hood crossmember out of the way of the crossover tube but this didn't quite make it. In the end, I did have to slightly relocate the hood crossmember. Simply drill out the spot welds, move back one bolt hole and reweld. There was plenty of slop to enable the slight move. There was a slight bump out on the side of the hood where the factory bent the hood to make the crossmember fit. Your hood may be different.
3. The coolant reservoir was moved slightly up and to the rear; remounted on a steel plate. I removed the original brass elbow on the coolant reservoir, welded on a new 90 degree, then 45 degree silicone hose, then aluminum pipe to connect to the engine coolant return. New parker hose and fittings reconnect to the radiator and coolant manifold.
4. The exhaust is aftermarket from PAI for a big cam. Part numbers rear to front: 3062568, 3062566, and 3065024. I am using the turbo in a "low" location, not all aftermarket exhaust manifolds have the dowel holes or enough flange to allow for the dowel holes to be drilled.
5. BHT3B turbo with 26cm housing, 167050.
6. The turbo drain line started with a stock multifuel flange/ pipe which was re-clocked to meet with a 1" 45 degree hose barb threaded into a 1" NPT bung welded into the original block cover plate.
7. The stack is from Amazon and hung with brackets from Amazon. There is a 45 degree elbow to fit through the fender, then a 90 degree, then a bellows from Summit Racing, another 90 degree elbow, straight section, then a flange to the turbo. I did have to cut the 90 degree fitting coming off the 45 at a slight angle to get things to line up. I used a quick connect flange to separate the stack between the 45 and 90 degree elbow.
8. I am using a 5.5" to 5" reducing elbow, then 5" pipe, then a 90 degree to the air filter. This part is not fully complete yet.
9. Unfortunately, I have not heard it run. It has been -13F and I have been unable to take it out or run it yet.

Let me know if you have any questions or comments.

 

[DeMilitarized]

I know that the title is a big claim but I really do think that this worked out well.

1. I used of a factory Cummins crossover tube (14224 and intake manifold. This particular intake retains the flame heater. While the turbo outlet and crossover inlet don't exactly line up this is easily fixed with two 23 degree silicone elbows and an inline coupling between the two.
2. I initially tried to simply bend the hood crossmember out of the way of the crossover tube but this didn't quite make it. In the end, I did have to slightly relocate the hood crossmember. Simply drill out the spot welds, move back one bolt hole and reweld. There was plenty of slop to enable the slight move. There was a slight bump out on the side of the hood where the factory bent the hood to make the crossmember fit. Your hood may be different.
3. The coolant reservoir was moved slightly up and to the rear; remounted on a steel plate. I removed the original brass elbow on the coolant reservoir, welded on a new 90 degree, then 45 degree silicone hose, then aluminum pipe to connect to the engine coolant return. New parker hose and fittings reconnect to the radiator and coolant manifold.
4. The exhaust is aftermarket from PAI for a big cam. Part numbers rear to front: 3062568, 3062566, and 3065024. I am using the turbo in a "low" location, not all aftermarket exhaust manifolds have the dowel holes or enough flange to allow for the dowel holes to be drilled.
5. BHT3B turbo with 26cm housing, 167050.
6. The turbo drain line started with a stock multifuel flange/ pipe which was re-clocked to meet with a 1" 45 degree hose barb threaded into a 1" NPT bung welded into the original block cover plate.
7. The stack is from Amazon and hung with brackets from Amazon. There is a 45 degree elbow to fit through the fender, then a 90 degree, then a bellows from Summit Racing, another 90 degree elbow, straight section, then a flange to the turbo. I did have to cut the 90 degree fitting coming off the 45 at a slight angle to get things to line up. I used a quick connect flange to separate the stack between the 45 and 90 degree elbow.
8. I am using a 5.5" to 5" reducing elbow, then 5" pipe, then a 90 degree to the air filter. This part is not fully complete yet.
9. Unfortunately, I have not heard it run. It has been -13F and I have been unable to take it out or run it yet.

Let me know if you have any questions or comments.

Good write up for those with A0/1 M939 trucks too! For some cheap power this would be a good mod but personally I don't see the time and effort worth it without an intercooler. On my 8.3 my aftercooler coolant temp reaches +300F with coolant temps at 180 on long hills which means the intake air is likely much warmer than that. Each degree increase on the intake is a degree increase on the exhaust side which means depending on very specific circumstances you could be making a net equal hp to NA. Just my thoughts and it may be much different with the NHC250.

 

[JasonS]

Good write up for those with A0/1 M939 trucks too! For some cheap power this would be a good mod but personally I don't see the time and effort worth it without an intercooler. On my 8.3 my aftercooler coolant temp reaches +300F with coolant temps at 180 on long hills which means the intake air is likely much warmer than that. Each degree increase on the intake is a degree increase on the exhaust side which means depending on very specific circumstances you could be making a net equal hp to NA. Just my thoughts and it may be much different with the NHC250.

Thanks. For this size engine and horsepower, Cummins didn't aftercool (at least to the best of my knowledge). Others who have done this mod have reported lower EGT numbers and have been able to increase the fuel.

 

[Superthermal]

Thanks. For this size engine and horsepower, Cummins didn't aftercool (at least to the best of my knowledge). Others who have done this mod have reported lower EGT numbers and have been able to increase the fuel.

Still planning on this mod down the road. It is so cool to see the application of skill by so many to make their mod work. I would like to run a water to air aftercooler just as insurance for my lead foot.
With what you have here, I like the exhaust. The matching your turbos output to the stock intake is excellent! The coolant tank mount is boss as are your oil return plate and drain. The use of a "stock" intake manifold with a heater is cool as well.
Getting a pyro on there would be important, and maybe a boost gauge for fun.
Looking forward to the rest of your build.
I cant tell you how envious I am of you having a shop to work in. Wow that must be nice!

Best wishes

 

[US6x4]

That setup looks good, clean, open, and simple. I like the retention of the cold start pieces and I'm glad I didn't see any plumber's tape anywhere.

 

[muthkw25]

Thanks. For this size engine and horsepower, Cummins didn't aftercool (at least to the best of my knowledge). Others who have done this mod have reported lower EGT numbers and have been able to increase the fuel.

I just turboed my m925a1 and I used a bigcam aftercooler and crossover pipe. I saw 300 degree drops in egts and that's with the probe in cylinder 6. That's with no core in the aftercooler as well. I saw 12lbs of boost peak. With 12lbs there's not enough boost to cause big issues with intake temps. I have a #27 button pump built by premco and adding 10% over injectors from premco this weekend. With my modest fuel settings I won't have an issue however, I have decided to run a n14 intake instead and run a small intercooler to help. I also have a methanol kit installed as extra.

I don't think you'll have any issues. You could also install a methanol kit if you wanted some peace of mind.

 

[US6x4]

Do you know what kind of engine the intake and cross over came off of? It looks like you could still fit 2 jake heads (front & back) with that setup

 

[muthkw25]

Do you know what kind of engine the intake and cross over came off of? It looks like you could still fit 2 jake heads (front & back) with that setup

I bet it came off a Ntc 290.

 

[Superthermal]

Don't forget to take the caps off those valve covers and put a stopper in the breather ports. I hear this is needed when adding the turbo. If you already did. Good job.

Where are the "breather holes" that need to be blocked when you turbo a 250?

I already spent over an hour searching the forum. Scrolling through 15 page threads etc., so I tried. I found mention of them, but that's it. I paid my dues! Where are they!

www.steelsoldiers.com

 

[Jbulach]

Do you know what kind of engine the intake and cross over came off of? It looks like you could still fit 2 jake heads (front & back) with that setup

IIRC, someone on here did two, mid and rear, but a third jake would not clear on the hood on front of the engine.

 

[US6x4]

IIRC, someone on here did two, mid and rear, but a third jake would not clear on the hood on front of the engine.

I found a way to add a front jake head (25B) without cutting the hood panel - only notching the hood stiffener cross member.

 

[JasonS]

I pie-cut a length of 5" exhaust tubing to create a 20° elbow and mounted the air cleaner. The air cleaner is supported on three points by structure under the fender; I plan on fabricating up something to support the fourth point. And, I need to finish up the side covers and mount the guard on the stack. Etc.

I really like it. Around 6psi boost going 55mph. Way, way louder than my deuce.

 

[Superthermal]

I pie-cut a length of 5" exhaust tubing to create a 20° elbow and mounted the air cleaner. The air cleaner is supported on three points by structure under the fender; I plan on fabricating up something to support the fourth point. And, I need to finish up the side covers and mount the guard on the stack. Etc.

I really like it. Around 6psi boost going 55mph. Way, way louder than my deuce.


View attachment 939921

That is great news! I just love it when a project comes together.
Question. I have considered when attempting this to put a muffler in the vertical stack rather than trying to scrunch one under the hood. Is the straight pipe like WOW louder than stock? Is it one of those... well that is cool!... then 20 minutes later is like... Ya it would be better making it a bit quieter... kinda thing.
Let me know your thoughts in a few weeks as you drive some smile miles on that fun mod.

One thing I was interested in that hasn't been so clear from others is a MPG gain or loss. I get 6.5 on highway miles. Like you I keep at 55 to ensure I keep the advertised speed rating in check. I am curious to see if you gain or loose mpg just because pressing on the fuel peddle actually does something now. LOL. I am not sure as I didn't catch if you had changed the fuel button at all in your pump. I was considering to do a 17. I did buy and have temporarily mounted a fuel pressure gauge and my freeway uphill under constant load max psi was 150. From all I read here we want to keep this below 200 as anything above gets you into flatten your cam type of pressures. I did already buy the button but I haven't put in a turbo or bought a pyrometer yet. After I do I will get that rolling.

Congrats again on your success. Best wishes.

 

[US6x4]

Even with my stubby muffler the loudness is manageable for about 30 minutes, but with the stack in the factory location the noise gets to be fork-in-the-ear sorta fatiguing. The stack behind the cab would help or a spiral, noise reducing insert like @Lonnie installed could help.

 

[JasonS]

Thank you all for the comments. I do feel fortunate to have a nice place to work and funding to pursue these hobbies. Really grateful to the wife who supports these endeavors with patience and finances.

I am a lot more protective of my hearing as I get older. I took the wife for a drive through town and on the highway. She didn't find the exhaust objectional and commented that it was louder than the deuce but not massively louder. I'd be wearing ear plugs or noise canceling ear buds. Really, there is not much better than a nice summer morning, blasting down the hi-way in the truck, looking down that long hood, tunes in my ears.

Since there is no smoke while driving, fuel economy has to be better. However, I don't have any real data before and none yet with the turbo. As hobbies go, regardless of fuel, this one is still pretty cheap.

 

[Superthermal]

On the 3 piece exhaust manifold:
Is this the same one used by @US6x4 for his setup?
Also you mentioned you needed to drill holes in it for dowels? What was the need for drilling if that is what you did.
I was thinking to use a Ht60 turbo and from what I can tell they look like the mounting patterns are the same. This might allow me to mount the turbo in the same orientation as you did or if this is the same manifold as @US6x4 used then maybe I would attempt running it flipped.

Is there space on this manifold to place a pyrometer? @US6x4 drilled his just inside the plate as seen in his pic I copied here below. I am hoping this is the same manifold or at least very similar.

My M813 gets a turbo!

In an effort to compensate for the power loss of running 16.00-20s (still a future mod), I started accumulating parts for adding a turbo to my NHC-250. The direction I'm going is nothing new as @Lonnie has already laid the ground work for the turbo layout I'm using, but I was also inspired by...

steelsoldiers.com

 

[JasonS]

The head has dowel pins on the bottom of the exhaust port gasket face which are used to locate the exhaust manifold on the head. The exhaust manifold has corresponding dowel pin holes. The aftermarket PAI has them on both top and bottom; the AKMI only on one side. This became an issue with one of the vendors who I dealt with and didn't understand this. On some aftermarket exhaust manifolds, there isn't enough face on the flange to add a dowel pin hole.

However, when testing another exhaust manifold, I did create a jig to drill the exhaust manifold for the dowel pin holes.