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Author Topic: 8V71 Air Filter CFM -- Had a great trip  (Read 3171 times)
Melbo
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« on: July 30, 2009, 10:28:37 AM »

Had a great trip from the mountains to the prairies but did not make it to the oceans.

I am running an L10 and ZF. Everything did what it was supposed to do however I am wondering what the CFM rating is on the stock air filter for my original 8V71. I am using the same filter for my L10.

I noticed that the exhaust is much cleaner when I get into the lower altitudes and I may want to change the setup I currently have to make it breathe better.

Just a thought but the starting point is the CFM rating of the air filter so I can redesign things.

For reference purposes we logged about 2400 miles and got about 6mpg not taking out for the generator running.

Melbo
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TomC
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« Reply #1 on: July 30, 2009, 12:17:12 PM »

Considering the 4 stroke equivelent displacement of the 8V-71 is about 908 cu in, your L10 at 610 cu in flows alot less air-so your air cleaner should be alright.  Combination of maybe worn injector tips, exhaust housing on the turbo that's too big (smaller housing will spin the turbo at a lower rpm), air cleaner element that is not clean, etc.

I just got back from high altitude driving with my 8V-71TATAAC and also noticed that it did smoke more at altitude then down at sea level-so it probably is normal for a turbocharged, mechanically injected engine.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Ed Hackenbruch
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« Reply #2 on: July 30, 2009, 12:26:00 PM »

Sure its gonna smoke more at higher altitude......the air is thinner so you are going to be running rich.  Same amount of fuel but less air to mix with it. Smiley
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1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
Melbo
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« Reply #3 on: July 30, 2009, 12:33:15 PM »

Tom

Thank you for the response. I know the tubo is the proper set up because it was redone after the transplant by Cummins Rocky Mountain here in ABQ.  I was thinking about replumbing to make a larger air intake opening and give me a little more access to the engine on the drivers side. Another bus nut that also has an L10 used an air filter that was more compact but had better air flow. I figured I could get some information to make plans to do something similar. Thanks for the thought that the more black smoke at altitude may be normal. I will keep that in mind also.

Melbo

P.S. Tom your truck conversion looks like it is coming along nicely.
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« Reply #4 on: July 30, 2009, 11:18:30 PM »

Melbo- I'm doing the final inspection tomorrow on the truck before giving the OK to install the aluminum skin (.062").  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #5 on: July 30, 2009, 11:50:46 PM »

After my recent mountain trip I changed the air filter, the old one didn't look to bad but what I noticed was the dirty one one weighed several pounds heavier. One good bang on a rock and I was surprised how much dirt came out, I guess there was a lot of dirt in it. On the subject isn't there companies that clean used air filters and resell them?
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Fraser Field
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« Reply #6 on: July 31, 2009, 03:16:08 AM »

About smoking more at higher altitude then sea level. All internal combustion engines need Oxygen to burn diesel fuel. Our outside air contains 21% oxygen. However, greater the atmospheric air pressure for 1 cubic the greater amount of oxygen. In other words….at sea level has more oxygen per cubic than higher altitude that will cause engine to burn rich or black smoke. Turbo will help reduce the unburned fuel or black smoke from the exhaust.
Why Less Oxygen at Altitude?


About the possible air intake restriction. A must have gauge is called Filter Minder. It very simple to install and you will wish you had it earlier. Cost about 35 dollars and never wear out. If you have too small a filter, plugged, too many elbows or too small inlet screen or whatever…it will indicate the results after driving thorough the gears.

They are available at any truck parts supplier, e-bay and NAPA
How Filter Minder Works?

Sojourn for Christ, Gerald
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Ed Hackenbruch
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« Reply #7 on: July 31, 2009, 06:15:05 AM »

You can clean your own filters. Just take an air hose with a nozzle and blow it out from the inside of the filter. Just keep working your way around the inside several times  until you are not getting any more dust out and then blow off the out side at an angle. You do not want to blow the dust/dirt straight back into the filter. Sometimes i work in very dusty conditions, ie. hood of truck is covered with a layer of dust/can't see the front of the truck while being loaded, and we just have the mechanic blow out the filters once in a while, sometimes as often as twice a week. You wouldn't believe how much dust and dirt can be in a filter under those conditions.  My own filters never see that much dirt and i have blown them out before, but usually i replace them on a yearly basis.
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1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
RickB
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« Reply #8 on: July 31, 2009, 06:57:29 AM »

With our HP starved 8v71 it didn't work cleaning the filter which is what I did last summer to save some money. The actual felt HP difference this summer with a new filter is nothing short of remarkable. Keep in mind that I had that old filter with all "visible" dust and dirt gone. Maybe with a 500 hp series 60 you don't feel a little bump in power but when you have a fairly low HP to weight ratio (like those of us with NA 8v71's)a bump of horsepower is really noticeable.

Mohawk sells them for alot less than a local truck shop. like 30% less.

After my experience I won't mess with cleaning another one I'll just replace it. After all we don't clean and reuse any other filters on our buses right??


Hope this helps and hope you are smiling as big as I was when you hit the first hill after you change it out.


Rick
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« Reply #9 on: July 31, 2009, 07:09:25 AM »

That would be an interesting experiment.  The next time you replace a filter, weight it first, then check the weight at the next service and again after you blow it out.
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« Reply #10 on: July 31, 2009, 07:56:30 AM »

I agree with Rick, you can't beat a new filter. Blowing one out is better than continuing to run with a dirty one however.  So if you go thru a dust storm or a very dusty construction area and don't have a new filter available or your filter is not very old i would blow it out.....but still keep in mind replacing it soon.
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1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
Melbo
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« Reply #11 on: July 31, 2009, 08:52:55 AM »

I do have a filter minder on mine now however I am wanting to change the housing and plumbing so I can increase the size of the opening where the air enters the filter.

To do that I need to know the CFM of the air filter that I currently have.

I had not thought of weighing the filter when it is changed that is an interesting idea.

Thanks for all the tips.

Melbo
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« Reply #12 on: July 31, 2009, 09:19:27 AM »

Does you filter housing have a manufacturer name and part number on it?  I know mine is by Donaldson, but my bus is also a lot newer than yours.
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« Reply #13 on: July 31, 2009, 09:21:34 AM »

 Melbo,
    Thanks for the info Smiley

    When you get it all figured out please take lots of pictures.
    You are the lead on this  Grin

    I can't remember who but one on here added louvers to the outside right infront of the air intake box. It helped increase the air movement.

    Just a thought

   Skip
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« Reply #14 on: July 31, 2009, 09:27:52 AM »

Melbo, FWIW the cone or tapered filters give more air flow for a turboed engine without compromising the air filtration on the engine just don't buy into K&N system.
I use  the ECO system on my 8v92 since I need 1600 cfm

Good luck
« Last Edit: July 31, 2009, 03:00:23 PM by luvrbus » Logged

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« Reply #15 on: July 31, 2009, 03:58:01 PM »

With the price of an air filter element less than $100.00, and an engine overhaul around $15,000.00- PLEASE all- do NOT blow clean the filter elements.  Blowing them out creates small holes in the paper elements thus letting dirt directly into the engine.  Just don't wait that long to change the filter-do it more often then you think, and the engine and you will be happier.  Good Luck, TomC
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« Reply #16 on: July 31, 2009, 06:29:54 PM »

I was told many years ago to not blow out filters, shake/bump them on the ground if you need to. New filters are not that expensive and like Tom said, it's a whole lot cheaper than a new engine. Blowing them out also distorts the protection and alignment.

Paul
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« Reply #17 on: August 01, 2009, 07:22:30 AM »

I know that the oil bath filters better than paper.  I also know that the oil bath MUST be appropriately sized to the engine for the filter to trap all the dirt in the oil AND be nonrestrictive.  Oil bath restriction to air flow doesn't increase with the time it has been in service since last being serviced.  Is any of this stuff I "know" wrong?

But!  Is the proper oil bath a better flowing and less restrictive filter at the beginning of the filter life?  If the paper goes thru it's life span moving towards a more restrictive, time to replace, item and the OB never needs service due to restriction the OB has always seemed, to me,  to be superior except from a difficulty point of view.

Thanks,

John
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« Reply #18 on: August 01, 2009, 08:35:18 AM »

Melbo,

To get back to your original question, how many CFM.....

According to Centriprecleaner.com, the 8V71 requires 875CFM, the 8V71T requires 1250 CFM. The L10 requires 594 CFM and the LTA10 requires 687 CFM

I would assume the 71 series Detroit requires more air because it is a 2 stroke and makes power on every stroke. The Cummins is a 4 stroke and makes power every other stroke.

http://www.centriprecleaner.com/engineguide.html

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Melbo
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« Reply #19 on: August 01, 2009, 11:48:54 AM »

Dallas

Thank you for answering the original question and saving the pixels.

Melbo
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« Reply #20 on: August 09, 2009, 08:55:56 AM »

Well guys I couldn't let this die about blowing out air filters some wrong info here about the subject.
I went back and read the owners manual on heavy equipment I have own over the years and Cat, John Deere and Bomag recommends you blow the air filter everyday at no more than 40lbs of air when working in dust.
Some of these filters cost over me over 250 bucks each and going with some of you guys recommendations that would have cost me 750 bucks a day for the Bomag as the were blown out 3 times a day sometimes  just food for thought    

good luck
« Last Edit: August 09, 2009, 08:07:53 PM by luvrbus » Logged

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