Filter Minders for Dummies

[davidbrady]

(03-28-2013 10:18)al perna Wrote:  what part of the system is now effected in a Negative manor ?

Your wallet Al! LOL

Seriously, in this case, the effect of shaving a few inches of water off will be so slight that our ECM's can easily compensate.

The stock system on our LXi's is free flowing with little pressure drop, and that pressure drop is easily within the DD 500 HP Series-60 specifications of 12 inches of water for a clean filter.

Certainly, you can spend money to shave a few inches of water off, but the efficiency improvement will be marginal, less than 1%, and it may not exist at all depending upon the flow rates of the new filter, the design of the new intake duct work, diffuser, and plenum, and the location from where it draws air. Also make sure that the "free flowing" nature holds up to miles driven. If the filter is mounted down low in the plume of road debris and moisture kicked up by our tires it may rapidly clog.

Before spending my money on something that's alleged to improve efficiency over our stock system I'd want to see third party real world testing, and certainly anyone selling a system would have that kind of data on hand. Grandstanding doesn't cut it for me.

If there is indeed an efficiency improvement, then do your calculation to see where the efficiency gain starts making you money. It doesn't make good sense to me to spend $500 on something that requires 100,000 miles of driving to break even. Few of us will ever put those kind of miles on our coaches; more than likely we'll move on to something else before then. If the seller is promising a 1 MPG improvement, run away fast!

At the very least, take a few minutes and call the filter manufacturer and get restriction specs at a flow rate of 1170 CFM for whatever filter you decide to go with. Compare these numbers to the ECO-SM numbers I published in a previous post. You may be surprised at what you find.

IOWs, I recommend doing some leg-work on whatever new design someone is hawking before committing.

Al, in this thread I've tried to present the data as unemotionally and as objectively as possible. I started by questioning the instrumentation (the Filter Minder), I provided some rationale for why it could be misleading, I questioned the FM's accuracy, resolution, response, mounting location, and the conditions in the engine compartment; I then looked at our stock intake system, I gave rationale for why I thought it's performance is within spec; I then presented pipe flow calculations for our intake duct work along with Racor-Parker restriction specs on our ECO-SM air filters, and Detroit Diesel specifications for clean and dirty air filter intake restrictions; I then did a calculation showing the pay-off time for an arbitrary improvement in efficiency; I've provided a baseline for the performance of our OEM system and tools and a methodology to compare to a third party "upgraded" system. I hope I've guided our membership along in this process on what's important in an intake system, and what performance is expected. I don't know what else to do for you AL??? I've laid out all the specs, data, calculations, and facts as clearly as I can. It's up to you now.

BTW, did you see my pictures of my intake air inlet? Is this what you have on your bus? When you mentioned and intake inlet "cap" you had me confused. Is the bell tip the "cap"?