Cummins 400 turbo boost and temp question

1 and 6 will be coldest unless there's an airflow issue preventing all the cylinders from getting about the same amount of air.

Other than that I can't say. I'd plan on moving that one probe around if your just gonna have one, just to be sure.

Under a load, all the cylinders run about the same. The center two have the highest temp readings due to the manifold converging there.

Now I think the real trick would be to have all the cylinders of any motor checked and if you could adjust the fuel to each cyl. and get all the temps. the same so every cyl. is pulling it's own weight. Know on some of the injected cars you can do it two cyls. at a time and adjust the duration / shot. Don't know if there is any Deisel or gas computer control motors now that you can do each cyl. alone but seems to me that would be extra fine of the builder.

StreetbikeDepot said:

My 915 makes about 20psi boost, 1050 degrees pre turbo and 165 psi fuel pressure (I am straight piped, my EGT's did run slightly higher with the muffler)

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Is that the correct fuel pressure for that motor. My NHC 250 called for I believe 170 and we bought it close to 180lb. Could yours be brought up some?

I will bump this.


So with the BCIII and the HT3B (167050) with a 26cm housing. Spools a little slow so maybe just swap the housing out with a 22cm (# 352183 housing instead? I need to get my boost gauge finished for what I have now. Slight leak on the divided manifold vs undivided turbo i need to address first i guess.

Or should i just bite the bullet and pay the price for an HT4B? I know the HT3B is said to handle up to 600hp and i am not planning on getting near that. I will hot the injectors probably this winter. Pump seems to run good around a 260 snap pressure with a 15 button.

EGTs, i dunno yet i need to install a pyro i guess. but long hills even at 70,000lbs the engine temp never climbs past 190 without the fan clutch on I have my aftercooler feed plumbed thru it's own small radiator before going into it.

You arnt building boost because your not loading the engine enough to make it work. Trust me that 3801919 will melt pistons, 40 plus lbs os boost no problem. I ran em on my semi for over 20 yrs

YOU DONT NEED ANY DUAL FUEL LINES, THATS KIDDIE THINKING. 1 NUMBER 10 AN LINE WILL FEED THE PUMP NO PROBLEM EVEN A 600 PLUS HP KTA ENGINE. IF YOU WANT TO SPEND SOME CASH AND BENIFIT FROM IT INSTALL A RACOR FUEL FILTER / WATER SEPERATOR. THERE EXCELLENT.

I RUN A 5 BUTTON BUT I HAD CORRECT CAM AND PISTONS FOR THE 3801919 BLOWER ALONG WITH CORRECT TIMMING AND OF COURSE PISTON OILERS IN BLOCK, A MUST HAVE..........
IT TAKES AN ENTIRE ENGINE COMBINATION TO MAKE HP N TORQUE

Keep me posted on what you put together for EGT and boost gauges and hardware. Your a mad scientist when it comes to figuring stuff out and I don't like to re-invent the wheel.

anything over 1000 deg on hot side is in the melting zone

Jeep Nasty said:

Keep me posted on what you put together for EGT and boost gauges and hardware. Your a mad scientist when it comes to figuring stuff out and I don't like to re-invent the wheel.

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21/22 psi at 2150 empty truck at 27,880lbs

Even @ 1000 deg. You,ll put cracks in piston domes............

bcowanwheels said:

Even @ 1000 deg. You,ll put cracks in piston domes............

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my small cam would run up to 1000 degrees easily and It logged near 200,000 miles with lots of extra fuel and air and it was NA with no squirters. A Big Cam will take 2700rpms or more and a good bit of EGT

Good read.

http://www.landlinemag.com/Magazine/1999/May/BottomLine/diesels.aspx

So around 17hp per lb of boost. I hit around 23lbs of boost on a short hard test. I do have a slight boost leak though.

https://www.youtube.com/watch?v=aNnxdSOBSAI

Ask Artisan how sustained 2700 RPM works. What his did is textbook for how it was being run.

Simp, what kit#'s did you end up using for EGT and Boost Gauges. Are they 12v or 24v? Also I like to see some shots of the ram air setup on your NTC-400. Also, what are you using for an alternator?

Jeep Nasty said:

Simp, what kit#'s did you end up using for EGT and Boost Gauges. Are they 12v or 24v? Also I like to see some shots of the ram air setup on your NTC-400. Also, what are you using for an alternator?

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My alternator is a 33SI. I used a normal civilian NTC400 alternator bracket and the same adjustment bracket. It is just strictly 24v though. Gauges are just Auto meter gauges. they are mechanical. The lights are 12v but i don't use the lights. I have interior lighting that allows me see them without their own lights.

My ram air system is a 46556 filter with the inner 46628 rated at 1325cfms. Stock 916 filter is 1200cfms. I added a blocker panel behind the filter so that it does not get any heat from the turbo. I have the side duct but i also have an 8in intake flow thru the hood panel where the old air intake for the heater blower was. That is just a deuce air deflector.

Jeep Nasty said:

Keep me posted on what you put together for EGT and boost gauges and hardware. Your a mad scientist when it comes to figuring stuff out and I don't like to re-invent the wheel.

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Took her out today for a post intercooler test drive.... I used the NHC250 intake manifold with 4" pipes and a 41"x21"X3" intercooler actually made for the RG-31 MRAP that only has a 6.7L in it.... But it is bigger than what a Kenworth or Peterbilt intercooler would be. I chose it cause it was an easy install to my radiator combo.

This 600 degree egt temp was towing the M322 empty. So gross is around 40,000#. Ambient temp is 60 degrees. Running at 60mph @ 2100rpms @ 10lbs of boost with a slight incline hill. So i am around 775 or so PRE turbo.

Wow that’s pretty good. Im starting to wonder how accurate the pyrometer I picked up is. On the Honey Badger with its stock engine setup as a m916. I’m running about 1000 degrees pre turbo at 2100 rpm 60mph 20 lbs boost Weighing 33,000 lbs and the aerodynamics of a cardboard box.

When I push it to 65 on incline, it almost 1100 and 24-26 lbs if boost.

I’ve been driving it the same for 2 years and about 5000 miles before putting in the gauges.




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Jeep Nasty said:

Wow that’s pretty good. Im starting to wonder how accurate the pyrometer I picked up is. On the Honey Badger with its stock engine setup as a m916. I’m running about 1000 degrees pre turbo at 2100 rpm 60mph 20 lbs boost Weighing 33,000 lbs and the aerodynamics of a cardboard box.

When I push it to 65 on incline, it almost 1100 and 24-26 lbs if boost.

I’ve been driving it the same for 2 years and about 5000 miles before putting in the gauges.




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About right that is about 850 post turbo. I have an intercooler now that is as big as your radiator is top to bottom. So i was probably in that range with the aftercooler.

Jeep Nasty said:

Wow that’s pretty good. Im starting to wonder how accurate the pyrometer I picked up is. On the Honey Badger with its stock engine setup as a m916. I’m running about 1000 degrees pre turbo at 2100 rpm 60mph 20 lbs boost Weighing 33,000 lbs and the aerodynamics of a cardboard box.

When I push it to 65 on incline, it almost 1100 and 24-26 lbs if boost.

I’ve been driving it the same for 2 years and about 5000 miles before putting in the gauges.




Sent from my iPhone using Tapatalk

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If you want to lower your EGTs without much work Chris then add an extra cooler to the front of your truck. You would Simply run a hose from the pipe that goes to the top of the aftercooler to it and the hose from your thermostat housing to it so that the coolant that is going thru the aftercooler is cooled down before it enters. This will drop some EGTs and help with cooling as well on any grades.

Some type of cooler with 3/4" ports is what you need. This will allow you to run Parker Push Lok Hose with their fittings on the 3/4" cooler and you will need a plastic hose connector adapter x 2 to get from the 1in engine side of the hose to a 3/4" parker hose to run thru it.

You can get some more power out of the thing by swapping out the fan clutch to one that is not on all the time either.

Jeep Nasty said:

Simp, what kit#'s did you end up using for EGT and Boost Gauges. Are they 12v or 24v? Also I like to see some shots of the ram air setup on your NTC-400. Also, what are you using for an alternator?

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Here ya go Chris.

@ 72,240lbs. The swift truck gets about a 1/4 of a mile lead on me and i close it on a hill without getting passed by any other trucks.

I ordered a turbo blanket and some exhaust wrap so I can get a little more boost. I was not on it all the way really as you can see the rail pressure never went past 160. Egts maxed at 1100 post turbo. Staying about 1000 post turbo thru much of the pull. 17lbs of boost max. I have a weak turbo hose so I did not want to blow that by too much boost. Never dropped below 57 on that hill compared to with the NHC250/16spd I would be down to about 25 or so climbing that hill trying to catch a gear.

https://www.youtube.com/watch?v=qXJ3-zy7vWU&t=46s