EGT Temps at Turbo

[doorguy]

I have an 04 CAT C7 330. Does anyone know what the EGT's range should be at the exhaust manifold during a normal operation, i.e., level road, mild ambient temperatures, 60 mph, etc.?

Also, under these circumstances, does anyone know what the EGT's should be at the turbo at the point where the PacBrake is attached?

[lwasouth]

I have an 05 Cat C7 with the 5050XL and the MP8 programmer. Have not measured the EGT's, but I relied on the the advise of several others that they remain safe with the programmer set at the half way point. Just returned from a 15000 mile trip with no problems. EGT should not be more than 1000 degrees prior to the turbo. There are several articles about this subject on this forum

[jauguston]

Delete

[jauguston]

Barry,

I just got home from a outing in the motorhome and paid attention to my gauges. I have a Isspro pyrometer and boost gauge on my 2005 C-7 350 with a MP-8 programmer.

We are about 32,000 pounds pulling our Samurai toad. Coach is a 2005 Coachman Sportscoach Elite 40'.

Flat freeway 60 mph 1700 rpm. EGT 1000° manifold pressure (boost) 12 psi. Slight uphill EGT goes to 1100° and manifold pressure goes to mid 20's. Slight down grade EGT goes to 300-400° and manifold pressure drops to below 100 psi.

If I put the transmission control in Econo mode and pull hard at 1400 the manifold pressure will be below 20 psi but the EGT will get hot fairly quick going to 1350 and heading toward 1400 if I don't lift. 1350 is supposed to be the safe limit due to this engine having steel rather than aluminum pistons but I am old school and don't use Econo mode at all for that reason. Pulling hills at 2200-2300 I don't see EGT higher than 1200 with the MP-8 turned up and 1250 with the MP-8 turned off. Manifold pressure will be 30-32 psi. Low RPM pulling hard=High EGT.

Hope that helps.

Jim

[1ciderdog]

Jim, out of curiosity, where is the EGT probe located on your engine?
Mine is after turbo in the exhaust brake and I do not get above 1100 or I should say I back off the throttle when it hits 1100. When pulling a grade such as the Siskiyous on I-5 I'll run about 2400 in third gear, EGT at 900 and boost at 30-32. I also have the MP and 5050XL muffler. I rarely use the economode, I never noticed any difference in mpg and I do feel the need for higher rpms on hills to help keep egt down.
Thanks
Bob

[jauguston]

My probe is in the exhaust manifold right next to the flange the turbo is bolted to. I drilled up from the bottom into one of the siamese ports in the manifold. I can't confirm it but over the years I have been told to expect somewhere around 300 degrees loss between pre-turbo and post-turbo temperatures. I also have my wastegate actuation hose disconnected and plugged. Max boost I see is 32 psi. When I bought it it was a dog and I found a best of 18 psi boost. Don't know why so I unhooked the hose and the boost is now just about what Cat said it should be-27.5 psi with MP-8 off. TS performance told me I should see 31-32 psi with it turned up and I do.

Has anyone besides me given up on the Catrvclub Forum. The new format is a joke and totally unusable.

Jim

[lwasouth]

When you say that the MP8 is turned up, what do you mean. 1/2 way as recommended or all the way?. Also I am not familiar with the "Waste Gate". Where is it and what does it do? Maybe I would like to try mine disconnected. My max boost is about the 27.5 with the MP8 set half way. It might be better to achieve 31 to 32. Would like to here your thoughts. Also have tried the Cat club site - It will take some getting used to.

[jauguston]

I run my MP-8 turned up until it makes the engine computer activates a alarm-a buzzer and check engine light when I am pulling hard. I then turn it down until the alarm stops. That is where tech support at TS Performance told me to leave it for best power gain and best fuel economy gain.

I am a retired crane operator/heavy equipment mechanic and have a lot of experience with diesel engines so what I do to my engine that is not what would be considered by most to be a good idea I would not recommend to someone that doesn't have that experience. If you don't know what a wastegate is and does I would strongly suggest you don't fool with it. The difference in performance between 27.5 psi and 32 psi is not going to be really noticeable. In my case I went from 18 psi to 32 psi and that was very noticeable.

Jim

[sevenmacs]

Quote:

Originally Posted by jauguston Barry, I just got home from a outing in the motorhome and paid attention to my gauges. I have a Isspro pyrometer and boost gauge on my 2005 C-7 350 with a MP-8 programmer. We are about 32,000 pounds pulling our Samurai toad. Coach is a 2005 Coachman Sportscoach Elite 40'. Flat freeway 60 mph 1700 rpm. EGT 1000° manifold pressure (boost) 12 psi. Slight uphill EGT goes to 1100° and manifold pressure goes to mid 20's. Slight down grade EGT goes to 300-400° and manifold pressure drops to below 100 psi. If I put the transmission control in Econo mode and pull hard at 1400 the manifold pressure will be below 20 psi but the EGT will get hot fairly quick going to 1350 and heading toward 1400 if I don't lift. 1350 is supposed to be the safe limit due to this engine having steel rather than aluminum pistons but I am old school and don't use Econo mode at all for that reason. Pulling hills at 2200-2300 I don't see EGT higher than 1200 with the MP-8 turned up and 1250 with the MP-8 turned off. Manifold pressure will be 30-32 psi. Low RPM pulling hard=High EGT. Hope that helps. Jim

So your saying that you will see higher EGT temp in the econo mode ? I'm asssuming your running your MP-8 at 30% (max setting)

[jauguston]

To explain more clearly the MP-8 on or off has little to do with the EGT except it does lower it a little. The thing that has a major impact on EGT is RPM and boost which are pretty much directly linked. The lower the RPM the lower the boost.

Where the Econo mode enters the picture is it changes the transmission shift points to a much lower RPM. With Econo mode engaged at full throttle the transmission will not downshift when pulling hard up a hill until the engine RPM drops below 1400. In normal mode it is much higher. At 1400 RPM the turbo is not moving much air and the boost is very low. The computer is still fueling the engine trying to maintain power but with the air volume going through the engine reduced by low boost that would normally help carry away the hot combustion gasses the EGT goes up and it goes up fast.

The fellow I talked to at TS Performance said they have run C-7's at 1500 degrees with no damage but I can't bring myself to do that. He said the reason it will live with EGT that high is the steel pistons. I find for me the Econo mode provides no appreciable benefit and I just don't use it. I occasional will see 1350 and that is my personal limit.

Jim

[doorguy]

Wow, nice detailed input from all you guys, helps me understand it more. Thank you.

[Mr. Brownstone]

Jim,
I know you have responded a few times to me on this subject and I really appreciate your help.
So if I go this straight then the higher the rpm's the better when working the engine up long hills. This helps clear the exhaust of high egt's. Right?
And you said the MP-8 didn't really affect the egt temps on or off?

Thanks

Steve

[jauguston]

It is really two different issues. When the transmission is in econo mode it keeps the engine in a lower RPM range where making power is the last thing your engine can do. At those low RPM's the turbo boost is very low and the computer is throwing a lot of fuel to the engine to try to make power enough to keep you going. At 1400 RPM I see about 16-17 psi of boost where at 2300 rpm in normal mode it is 30-31 psi. That then means there is not a lot of air being blown through the combustion chamber to carry away the heat. The MP-8 can't do much to help make power when the engine is lugging that slow because you are telling the transmission to keep the RPM down. If you are going to run with the transmission in econo mode my belief is you are going to waste your money with the MP-8. Its purpose is to make power not economy. There can be slight fuel mileage improvements with the MP-8 if you drive it not using the newly available power but what is the fun in that (-:

Jim

[stuhly]

Those steel pistons might stand 1500 degrees but the turbo will not for long.