diesel question???

[Bee]

ok my cummins is hitting past 1350degree on EGT. I have my limiter set at 1350degree so to cut fuel if it pasts that limit. using TST box... in warmer weather in spring/summer I can have it on level 5/5 - 5/6 and not hit EGT's over 1350, but colder weather like now I always hit the limiter even in level 4/4 and even at levels 3/3 at times.

colder weather means denser intake air which could possibly lean out a GASOLINE type engine, but diesels may be different. According to what i've heard and read all alike.....

I've heard so many different opinions. some say leaning could be from too much fuel/diesel... and some say you can never have to much DENSE cool air..... so if i get this dense cool air in the winter weather then why the heck am i leaning out...

so answer this: do I need more diesel fuel to keep EGT's down
or do I need the warmer air to keep EGT's down???
i'd like to keep the cooler air and at the same time keep EGT's a bit lower...

again remember in cool weahter EGT's are higher in my case!!!

[88camaro]

you might want to ask poeple on this web site.

http://www.performancetrucks.net/forums/index.php?

[MoreTorque]

I am not sure if they still use it, but on my 1999 Ram with the Cummins, they had a plate that opened and closed a bit right after the turbo. In cold temps, it would close to restrict flow and help the truck warm up quicker. The reduced flow also caused higher EGTs.

Thats all I can think of.

[BAD LS1]

i think a diesel is gonna operate like any other internal combustion 4 cycle engine, less fuel, more exhaust temps from running lean... Lift pump cant keep up anymore? lots of airation going into the pump or something... When its cooler out like this, the engine is FOR SURE gonna make more nuts thus requiring more fuel... im preaching to the chior now...

[MoreTorque]

It may also be the winter blended fuel not working as well in the truck...

[SmokinRAM114]

i no the winter blend fuel burns alot hotter then normal diesel. my uncle in MN got the winterblend at the local farm n barn KEW KEW And put it in his 05 f350 6.0 and the service engine soon light came on cuz the egt's were to high. i never heard of us in WI having winter blend unless maybe the fly'n JAY on ryan road. im sure u need less fuel. thats what i no most ppl have when they try to get alot of HP out of a diesel by dumping more n more fuel, there EGT's get to high. IMO

[Bee]

i no the winter blend fuel burns alot hotter then normal diesel. my uncle in MN got the winterblend at the local farm n barn KEW KEW And put it in his 05 f350 6.0 and the service engine soon light came on cuz the egt's were to high. i never heard of us in WI having winter blend unless maybe the fly'n JAY on ryan road. im sure u need less fuel. thats what i no most ppl have when they try to get alot of HP out of a diesel by dumping more n more fuel, there EGT's get to high. IMO

yeah ok so true ... more fuel = higher EGT
the cool weather has nothing to do with my EGT's going up...cool charge of air for diesels actually lowers EGT according to some of the sources i've been asking. My problem is defueling now for lower EGT's... dang it!!!

Now i'm thinking maybe my tst box is bad.... gosh darn it!!!!

[SmokinRAM114]

ya that would be what i would think... is less fuel. my dad has the Bully dog system on his 02 duramax with the monitor. he hasnt had any problems with it so far this winter. he just put it in befor winter.. can u adjust the defueling on the tst box? the bully dog u can adjust the defueling between shifts or something like that.

WHERE IS CARBON04 when someone needs diesel help!!! LOL

[carbon04]

Sorry I haven't been around much. High EGT's are from excess fuel and or lack of air. In your case the stock turbo on the cummins is very very small for the volume of air required to clean up the extra fuel from the TST box. Do you have aftermarket exhaust? A 4" exhaust from turbo back will lower EGT's about 150-200*. IIRC your stock wastegate is solenoid controlled. Which in turn is controlled by the TST box. The TST box holds the wastegate closed for added psi but in turn pushes the compressor well passed it's efficiency. I wouldn't be worried about 1350* egt's unless it's sustained for long periods of time 2+ minutes. At the end of the 1/4 I am pushing 1600*+ with no problems. Larger exhaust, more efficent turbo or less fuel............thats all you can do to reduce temps.

On another note forget everything you learned about air/fuel ratio when it comes to diesels. there isn't a A/F gauge with a wide enough range to work on a diesel in normal operating conditions. If you run too lean it just won't run, it won't burn up or cause damage it will just lose power to the point of not running. If you run too rich it will smoke excessively and cause high EGT's which can melt stuff but in turn will make excellent power. When running N20 on a diesel you keep jetting up until you run slower then back off 1 size(leaned out too far lost power). Hope I could help.

[Bee]

ok cool.. so somehow either my turbo got pretty bad since summer or my TST box is feeding too much fuel now... I GET IT!!! diesel

the thing that sucks is that TST doesn't have a defuel option.

another question.. most cummin TST gets 35-37psi on level 4/4, but i'm getting 41-42psi..... don't know why.. everything is hooked up correctly.. no leaks etc etc... you suggest the BOX itself is bad???

Also what is a good stack for the TST....something that can DEFUEL preferably...

thx carbon

[carbon04]

Don't know about the boost, I suppose it depends if they had different OEM calibrations for that year. The TST is a race box, no safety options. We are on winter blend diesel now so that may have a lot to do with the higher EGT's (depending on what that particular station uses for a blend). It's usually a blend of kerosene/diesel. The more they blend the less energy the fuel has. Where are you taking your boost reading from? If it is pre charge cooler that would be the reason why. Most (not all) of the people with boost gauges on diesels are worried about manifold pressure not turbo outlet. The monster OEM intercoolers aren't the most effiecient eating up a few psi.