I know my sig is a 6.7 but I need to ask some 5.9er's about an afermarket plenum. I noticed that I gained 4psi of boost and my idle egt's are about 50° lower than stock. Also at 100mph with the edge turned up my temp was 1050°, so im happy there. But I noticed that the egt's fluctuate really fast and it climbed up to 1500° and just as soon as it does it drops once the truck catches up with the throttle. I will post some pics of it later but I know the truck pulls better especially on take off. My whole theory is that more air means more fuel has to be added so there will be a temporary gain until she levels out. Btw the intake is super smooth, i've just never experienced a new plenum, and advice will help and what alhave y'all heard or experienced

Thanks
Dayton

 

If I understand what you are saying, I would disagree with your theory.
If that were true, adding twins (and boost) would have killed my mileage.

RJ

 

I'm with RJ.. More air with less restriction is better for the Diesel combustion process. If you can get more air into the engine with the same or similar fueling, you get lower EGT's and better combustion.

Understandably, if you are driving based on EGT, with more air you will add more fuel......with your foot....

 

remember, boost psi is a measurement of restriction. diesels are not like a gasser with more air=more fuel.

 

I worry about you Chris! Is that the Albuquerque DTR #0 Club?

RJ

 

well I was thinking that the one on the left might be Irocpractice, next over might be Blake, and then Scotty (the hat is covering the tin foil he usually wears), then Cincy and Chaikwa and then possibly Top. lol

 

Have you met Scotty? It would take 4 of those guys to make up one LEGG..

 

Probably only three now J.

With regards to the topic of more air and more fuel.

On the 6.7, have a look at one of your sensors in the air stream.

It has a scoop like look to it. I tried changing its position and the truck fell on its face at low throttle and low air flow over that sensor. What I did was I turned it sideways in a different adapter for a filter and turbo inlet hose I had 'laying around'.

I believe that if I can make the capture area slightly larger on the scoop like part of this sensor, the ECM will adjust fueling. I could be wrong. However, the loss of power with the sensor being turned sideways where it would not capture the air flow tells me its tied in somehow.

I think all Ram Cummins trucks shouldsuck COOL AIR!



Chris needs no air on his 9-volt Komode-Mobile

 

How in the heck did I get dragged into this....

 

Scotty, I forgot about the hard manual labour on the the science shed lately and not training for the heavy stuff..

This finding might explain how the Shibby intake horn messed up a friends truck a bit. It would cycle the fan more often even under no load causing some long regens etc.

 

It sounds like Scotty is talking about the sensor downstream of the MAP prior to the turbo. I don't know how the speed of the air would affect the fueling, the algorithm should be based on pressure and temp to determine density. Adding more air does not always mean adding more fuel. More air means more oxygen and IIRC oxygen is pretty explosive. Just think about how a Ram-Jet works, uses fuel until it is up to speed then it only burns oxygen.

J, I'm working on a single plane to divert the EGR gases away from the MAP/Temp sensor without disrupting the flow advantage of the intake. Driving without the Shibby right now and I feel deprived.

 

the intake velocity would have to be stupid fast for a ramjet type affect to take place.

with a ramjet being efficient at mach 3 and up to mach 6, we won't even come close to those speeds. lol