Manifold Temperature, ISM

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Manifold Temperature, ISM

September 15, 2017, 05:03:19 pm

I have a VMSpc supplied by and installed by Roger Engdahl. From it I have been getting data that before I did not have. One is the Mfold Temp. I interpret that as manifold temperature.

The data has been that the temperature, and assuming that I am right it means manifold, was around 70 - 75 degrees for about 750 miles.

Recently it went to 116 degrees of the final 100 miles home. I did not know what that meant and do not recall where the Forum offered a recent answer. I believe I was advised to talk to Cummins about my specific engine. This is their report:

a. My engine does not have the EGR, i.e. no def fluid or such. No temperature monitor of the exhaust gases.
b. I do have a temperature sensor at the manifold (I interpret as intake to the combustion cylinders)
c. The normal temperature at that sensor should be no higher than 30 degrees above ambient temperature. On the day I read 116 as the highest, and the ambient was about 90 degrees or a bit more
d. Regardless of "c", the manifold temperature should not exceed 120 degrees
e. IF the temperature becomes too high, it can damage the turbo. The high temperature does not mean there is no oil lubricant but a lack of coolant......per Cummins.

Now I am going to guess what I was thinking....please clarify. The turbo takes in air and supplies pressurized air to the intake manifold via the CAC. If that air is not cooled as much as desired, it means the turbo is hotter than it should be and, or the CAC is not cooling it properly. That my mental model.....is it wrong?

For some reason the intake air to the combustion is not cooled sufficiently if the temperature is above 120 degrees and as I HEARD the lady at Cummins, it seemed to implicate some cooling may be insufficient in the turbo, so it puts out too hot air. But IF my mental model is correct, and the CAC is between the turbo and operates to cool the turbo pressurized air to the manifold, the CAC could be at fault? And also bring to mind, what is used to cool the turbo beside oil, I guess I did not know there is a coolant line to it, but if so it could be at fault.

(Cummins noted, it could be a bad sensor, part number 3085185)

For further information not related to this topic: my oil temperature ran between 198 - 208 and my coolant between 177 - 208. Cummins reported those aer both good.

SO.....I hope this topic is of general interest and educational, and that those that understand how the air is processed and cooled can shed light on what I do next. Turbo or CAC or some other coolant flow is a concern or it sounds ok, as it is below 120 degrees and not more than 30 degrees above ambient. ---I would like more margin of error in that temperature range--

(must be a simpler way to state all this!)

mike

Re: Manifold Temperature, ISM

Reply #1 – September 15, 2017, 05:21:29 pm

Think you need to look at your boost pressures too. At higher boost pressures the air is being compressed more and the CAC must work harder to reject the heat. Also if your turbo can reach its max boost pressure, about 28.5 psi by vmspc, it would indicate to me it is operating correctly. I normally run about 20 degrees above ambient, but if running at high boost pressures, will go over that momentarily. Believe turbo is only cooled by oil.
First thing I would do is a careful inspection of your CAC and look for exhaust leaks in the engineroom, if you have a heat source close to any of the CAC piping, this could also cause higher temps.

Re: Manifold Temperature, ISM

Reply #2 – September 15, 2017, 05:37:38 pm

John, it comes to mind that intake manifold air temp is influenced by how hot the exhaust gas temperature is, as this very hot air spins the turbo and some of the heat it transferred to the air coming from air filter. So a question would be how hot was the EGT (exhaust gas temp) on your last 100 miles.

Also coolant temp would indicate how hot the engine block was at this time.

Then again, who can fault the horses working harder as they get closer to their barn.

Re: Manifold Temperature, ISM

Reply #3 – September 15, 2017, 05:46:09 pm

Quote from: Barry & Cindy – September 15, 2017, 05:37:38 pm

John, it comes to mind that intake manifold air temp is influenced by how hot the exhaust gas temperature is, as this very hot air spins the turbo and some of the heat it transferred to the air coming from air filter. So a question would be how hot was the EGT (exhaust gas temp) on your last 100 miles.

Also coolant temp would indicate how hot the engine block was at this time.

Then again, who can fault the horses working harder as they get closer to their barn.

Yes, if the EGT is too high, that is a big problem and points to engine or ecm problems. Trouble is the only way to obtain exhaust temps is to install a pyrometer in the exhaust manifold or after the turbo. Cummins does not use this temp so there is no sensor and thus vmspc cannot read it.

Re: Manifold Temperature, ISM

Reply #4 – September 15, 2017, 06:31:59 pm

I don't see any way that the intake temp. cannot exceed 120 deg. If the coach was running in 110 ambient temp the air cooling the CAC would be at least that temp. The boost compressing air would raise that temp. My crane has no CAC and at 20 lbs. boost on a hot 110 deg. day here would definitely exceed 120 deg. I believe the part about not exceeding ambient temp by 30 deg. being the factor, and if it was 96 deg. on the day of the reading 126 would be the ceiling.

Re: Manifold Temperature, ISM

Reply #5 – September 15, 2017, 06:53:17 pm

Agree, the only sensible parts of Cummina answer was that manifold temp should not be over 30 degrees higher than ambient.

Re: Manifold Temperature, ISM

Reply #6 – September 15, 2017, 06:57:28 pm

Mike, from what I have been told you are in the normal ranges. My intake manifold temps are normally 10-25° above ambient. The higher end when it is hot outside and/or the engine is working harder. And that doesn't mean mountains, coming across Oregon on two lane hilly, winding roads, 40-60 mph, lots of acceleration and slowing down and temps in the 90's we saw the same intake manifold temps, about 115°.

I wouldn't be chasing something that is still in the normal range as I understand it. What you want to look at is changes and trends. Is it consistently higher than it was? Is it going up? My oil temps get to 205° on occasion. I checked and that was OK. I bumped up my oil temp yellow light to 206 from 200°. I just want to know if it gets warnpmwr than that and stays warmer.

Be calm.

Roger

Re: Manifold Temperature, ISM

Reply #7 – September 15, 2017, 07:07:34 pm

We found a pyrometer EGT that uses normal wires from engine to dash, so we can use OEM extra spare wires. The normally required gauge calibration is done at factory and locked into the sender assembly.

Works very well, and we drive every up mountain with EGT & RPM, manually choosing the needed gear to stay below about 900 degrees and 1,900 RPM, which results in coolant generally staying around 180.

pyrometer/ETG sender VEI EGT Sender 1800-f SEN-TCI 95.00

pyrometer/ETG gauge VEI V1-PYF-MR/B $65.00

Re: Manifold Temperature, ISM

Reply #8 – September 15, 2017, 07:26:43 pm

Quote from: Barry & Cindy – September 15, 2017, 07:07:34 pm

We found a pyrometer EGT that uses normal wires from engine to dash, so we can use OEM extra spare wires. The normally required gauge calibration is done at factory and locked into the sender assembly.

Works very well, and we drive every up mountain with EGT & RPM, manually choosing the needed gear to stay below about 900 degrees and 1,900 RPM, which results in coolant generally staying around 180.

pyrometer/ETG sender VEI EGT Sender 1800-f SEN-TCI 95.00

pyrometer/ETG gauge VEI V1-PYF-MR/B $65.00

I bought the same one on your recommendation and find it invaluable in mountain driving.

Re: Manifold Temperature, ISM

Reply #9 – September 15, 2017, 07:36:40 pm

Quote from: jcus – September 15, 2017, 07:26:43 pm

I bought the same one on your recommendation and find it invaluable in mountain driving.

Where are you putting the sender? Big variation on what temps are safe depending on sender location.

Re: Manifold Temperature, ISM

Reply #10 – September 15, 2017, 07:46:25 pm

Quote from: craneman – September 15, 2017, 07:36:40 pm

Where are you putting the sender? Big variation on what temps are safe depending on sender location.

On elbow into turbo between #3 and 4 cylinders. Diesel hot rodders say this is a much better location than after turbo, and most engine makers who include pyros place it it before turbo.

Re: Manifold Temperature, ISM

Reply #11 – September 15, 2017, 08:15:15 pm

Mine stays 10-20 degrees above outside temp. Every now and then if I have to roll on before the t stat has opened it will go to 135+ along with sensor out of range code. Like others say long hard pull at full throttle and coolant temps going up it will get warmer. Have you washed your rad CAC out recently.

Re: Manifold Temperature, ISM

Reply #12 – September 15, 2017, 08:42:56 pm

Bruce, thanks.....I do wash before each trip. Now it may be I should use more than water, but I think I read you need to be careful of what cleaner you might use that it not damage something......so I just use water, and not a pressure washer.

Barry, I imagine the EGT gauge would be good info......I recall several threads on the Forum and recently the importance reviewed in some motorhome magazine.

thanks

Re: Manifold Temperature, ISM

Reply #13 – September 15, 2017, 11:59:51 pm

Jim put the EGT sender in the right place.

I was reluctant to drill cast iron so we drilled the pyrometer hole in the steel output tube just after the turbo. Another reason to not go much over 900 degrees on our dash meter, as the exhaust manifold and valves are hotter than our EGT reading.

Glad you like the meter design Jim. We also have the matching boost and our max psi is 29 psi.

Boost sender VEI SEN-P70B $35.00, and dash boost gauge VEI V1-BHEP-MR/R $95.00

Re: Manifold Temperature, ISM

Reply #14 – September 16, 2017, 05:53:01 am

Drilling the exhaust manifold is very easy. It drills like butter. Just grease the drill bit to minimize pieces dropping into the manifold. Anything that does drop will be instantly blown out anyway.

Re: Manifold Temperature, ISM

Reply #15 – September 16, 2017, 09:59:32 am

Blown through the turbo???

If you put the sensor after the turbo, no problem (except temp reads lower), but the exhaust manifold is obviously before the turbo so I don't think metal shavings going through blades would be a good idea. Maybe I am missing something...

Wouldn't be the first time!
Don

Quote from: amos.harrison – September 16, 2017, 05:53:01 am

Drilling the exhaust manifold is very easy. It drills like butter. Just grease the drill bit to minimize pieces dropping into the manifold. Anything that does drop will be instantly blown out anyway.

Re: Manifold Temperature, ISM

Reply #16 – September 16, 2017, 10:22:30 am

Quote from: Don & Tys (AKA acousticart) – September 16, 2017, 09:59:32 am

Blown through the turbo??? If you put the sensor after the turbo, no problem (except temp reads lower), but the exhaust manifold is obviously before the turbo so I don't think metal shavings going through blades would be a good idea. Maybe I am missing something... Wouldn't be the first time!
Don

The grease will catch most of the shavings, some people put a stick magnet into the hole after drilling to pull out any shavings left,
Even heard of some people leaving engine running while drilling. Diesel hot rodders have been doing this mod for 20 years, and I have never read or heard of any turbos being damaged. Banks, a big name in diesel truck performance sells a pyro kit and recommends drilling into the manifold with grease on the bit also.

Re: Manifold Temperature, ISM

Reply #17 – September 16, 2017, 12:38:25 pm

on a good climb I go to 34lbs boost with the Banks. My pyro sensor is under turbo in manifold mouning for turbo. Done at Banks.
JohnH

Re: Manifold Temperature, ISM

Reply #18 – September 25, 2017, 05:54:12 pm

I have had the coach in the shop and reviewed the VMSpc manifold temperature. This is what I learned,

a. Fan sensors working properly, fan worked correctly, no leaks in charge air pipe.

b. Cummins reports to shop, Warning temperature is 165 degrees and shutdown at 170 degrees. Maximum rise over ambient allowed is 30 degrees

c. Cummins reported best air temperature is between 60 and 90 degrees. Engine hp drops about 1% for each 10 degrees of intake air above 90 degrees. An engine rated at 250 hp will develop 240 hp when air intake is 130 degrees with same fuel delivery.

Mike

Re: Manifold Temperature, ISM

Reply #19 – September 25, 2017, 06:43:00 pm

There is a 300 to 500 degree location difference on a 5.9 Cummins. See: EGT Probe Location: Pre-Turbo or Post-Turbo? – GlowShift Gauges Blog I would not go past 1250 degrees for a sustained period.

We drilled the manifold when we first started installing turbos on Mercedes 240Ds.

Pierce

Re: Manifold Temperature, ISM

Reply #20 – September 25, 2017, 09:37:07 pm

Quote from: Michael & Jackie – September 25, 2017, 05:54:12 pm

I have had the coach in the shop and reviewed the VMSpc manifold temperature. This is what I learned,

a. Fan sensors working properly, fan worked correctly, no leaks in charge air pipe.

b. Cummins reports to shop, Warning temperature is 165 degrees and shutdown at 170 degrees. Maximum rise over ambient allowed is 30 degrees

c. Cummins reported best air temperature is between 60 and 90 degrees. Engine hp drops about 1% for each 10 degrees of intake air above 90 degrees. An engine rated at 250 hp will develop 240 hp when air intake is 130 degrees with same fuel delivery.

Mike

60 to 90 degrees? man thats like winter here

.. summer it hits 120.. should feel the inside of the coach .. un bearable and takes a month to cool down inside

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