Multifuel engine intercooler

[cranetruck]

Installed two more temperature probes today to measure the effect of the water cooled intake manifold.
Drilled a 1/16 inch dia hole at the cylinder #5 intake (see image) and also a 1/16 inch dia hole in the intake manifold adapter.
Two thermocouple bead type probes were installed.
I also installed a temporary pressure/vacuum gauge to monitor the air filter canister vacuum.

After warming the engine to about 175F and making preliminary measurements, I took the deuce on test drive.
On a long uphill run in 5th gear at 55 mph the engine temp was 185F, the pyro showed 1,100 F, the boost gauge 10-11 psi, the adapter temp 222F and the temp at #5 cylinder 210F. The cooled intake manifold acts as an itercooler here.

Love that friggin multi!

The vacuum was 2 inches of water at 2,000 rpm, it pegged the needle at 2,500 rpm (conditions as above). The gauge only goes to 2 inches.

 

[cranetruck]

Mounted the DVM/thermometer on the air intake since the thermocouple wasn't long enough to reach the inside of the cab from the intake manifold adapter.

 

[Recovry4x4]

There is so much more to these engines that us commoners haven't discovered. Sure a bombed B series might outrun it but I really love my multifuelers! Great information Bjorn.

 

[Djfreema]

That is some really great info! Once again, another successful experiment by Cranetruck! Now I will stop daydreaming of a big FMIC on my duece.

 

[cranetruck]

The results are preliminary, but interesting never the less. The filter vacuum reading is inconclusive since the gauge pegged out at 2 inches of water. Incidentally, the air compressor is getting its air from the canister as well, but there was no indication on the gauge when it was loaded (sucking air).
The ambient was about 62F. Deuce as shown below.
The air temperature must be different for the individual cylinders since the paths from the intake manifold adapter vary in length. Number 3 cylinder must be getting hotter air than number 6 for example.

I drilled the holes knowing that some debris would fall on the inside of the manifold, but it's all aluminum and a test drilling on a spare manifold resulted in very little debris. The thermocouple probes are 1/16 inch dia and fit snuggly in the holes.

 

[cranetruck]

Installed a vacuum gauge with a wider range to measure the vacuum in the filter canister. Made another test run.
With a pyro reading of 1,100F and a boost of 11 psi, the vacuum reading was 20 cm of water. That was the max I saw.
This is a new filter with about 1,000 miles on it (courtesy of Kenny Engle) and should provide a reference for you who may want a different filter cartridge.
BTW all the test runs today were made with 100% petro diesel.

 

[Djfreema]

It would be interesting to see the filter canister vacuum readings with a K&N air filter and aslo the charge air temperature readings before and after a K&N filter.

 

[mangus580]

Great Info Bjorn!!! Glad you were able to do it. Now that leaves one question to ponder..... would an intercooler be of benefit? Is there any benefit to dropping that temperature even more?

 

[rizzo]

how are you cooling the intake?

 

[mangus580]

cooling is happening by the antifreeze coolant that goes through the intake by design of the multifuel engine.

 

[cranetruck]

Right, the intake manifold is a double walled aluminum casting, cooled by the coolant. The thermocouple probe was inserted in a part that is not double walled near the entrance to the cylinder #5 (image above).

 

[rizzo]

so all the engines intakes are cooled?

 

[cranetruck]

All the multifuel engines have this intake manifold.
It's only cooling for high boost, doesn't do much for anything less than 6-7 psi after the engine warms up. It's not going to reduce the temp below engine op temp.

 

[cranetruck]

This from knfilters.com :
For maximum efficiency, diesel air filter restriction should be less than 25 inches of water vacuum, compared to a gas motor which uses only 10 inches of water restriction. Since diesels work harder at pulling air into the engine this creates a greater opportunity for dirt and silicates to enter the engine. Dirt or silicates in the engine can cause severe damage, including cylinder wall wear.

I measured 20 cm of water, which is 8 inches of water, so a new standard filter should be comparable to the K&N spec., unless I'm missing something here.

EDIT: The missing factor is the airflow. The K&N filter has a flow restriction of 4.3 inches of water (11 cm of water) at 350 CFM. We just need to figure the air flow for the multifuel engine under conditions reported above.

 

[cranetruck]

Chime in and correct me here if I'm wrong.

The engine displacement is 478 cubic inches, which is 0.276 cubic feet.
For 2,000 rpm, the air flow is displacement x rpm divided by 2 = 276 CFM

During turbo boost there is the additional flow as a fraction of atmospheric pressure to add in, so for a boost of 6 psi, which is 41% of 14.7 psi (pressure at sea level). Adding 41% to 276 cfm gives us an an air flow of 389 CFM at 2,000 rpm.

For 2,500 rpm the flow is 345 CFM plus a boost of 11 psi (78%), which gives us 614 CFM.

So, the vacuum measurement above (previous posts) of 8 inches of water is for a flow of 614 CFM.

 

[rdixiemiller]

So a filter that flows 800cfm at initial install with a low suction pressure should be a good thing.
Agreed?

 

[red devils dude]

this thread is one of the best ever, thanks Bjorn
So we've established that a K&N would most likely be a improvement.

 

[mcinfantry]

i thought a stock air filter permitted that much air flow?

 

[cranetruck]

Measuring the restriction of the air filter is a little tricky while driving, but I took the deuce to the store this morning and checked the numbers as I was driving.
According to this site, the comparisons are made at 350 CFM.
http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

Driving at 2,000 rpm with a turbo boost of 3 to 5 psi requires approx 360 FM of air. My vaccum gauge showed about 8 cm of water (3.2 inches of water).
Also at 2,000 rpm and about 1 psi of boost (315 CFM) gave me 5 cm (2 inches) of water on the gauge.
At 2,400 rpm and about 10 psi of boost gave me 15 cm (6 inches) of water. That's about 550 cfm.

The filter only has about 1,000 miles on it, so it's pretty clean.
Looks pretty good to me, but somebody else should make similar test runs for a more accurate picture.

 

[Djfreema]

Does the "410 CFM" stamped on the stock paper filter mean that it is only good for 410 cfm of air flow?