: Which size Filtermag are you using?

07-19-09, 07:08 AM
I am about to purchase a Filtermag. Which strength are you guys using-- the SS300 (90#) or the HP300 (250#)?

I am finding it difficult to find much objective information on the worth of either outside of the oil analysis on Filtermag's site, only the usual "I wouldn't run my car without it", etc. posts.

I am aiming for the HP model--more particles pulled must be good, I assume.

Anyone done their own oil analysis using a Filtermag? If not, I am considering volunteering if I can find a lab in the Cleveland area.

07-19-09, 10:24 AM
iunno i know that i had mine put on at the dealer before i even drove off the lot. At a whopping 4 miles.

07-19-09, 11:01 AM
Don't know if this helps, but might be worth asking Blackstone Labs.



07-19-09, 05:22 PM

07-19-09, 10:16 PM
If you actually want to buy the product, don't order it from the FilterMag company itself. The cheapest prices are from an internet-based company -- Innate (located near Omaha) -- that specializes in custom paint jobs. You might ask why a company that specializes in car paint would carry "magnets" for engine, transmission, and differential systems. As they explain at the bottom of their web page on the product (see below), they have used FilterMags in the large number of vehicles that they own, and were so impressed with the product that they decided to distribute it:


If you do decide to buy the FilterMags, be sure you get the "racing" (RA) version of the magnet for the V's oil filter -- which is stronger (and more expensive) than the SS ("standard") or even the HP version of the magnet. Also, a FilterMag rep told me that the "light" version of the transmission (TM) magnet was more than sufficient for even a performance car. The "heavier" transmission magnet is used on big trucks.

Here's the parts number and pricing for the 3 magnets at the Innate company (at least as of a few weeks ago). The diameter size listed for the RA magnet is specific to the size of the oil filter on the V. However, the transmission (TM) and differential (DM) magnets are the same recommended version across all cars. Also, the differential magnet is for internal installation, so you will have to wait to use it the next time you drain your differential fluid.

RA300 - Filter size range: 2.90"-3.20"
Only $58.20

TM180 - Filter size range: 2.9375” x 1.9375”
Only $26.95

DM101 - Filter size range: 2.0” x 1.25”
Only $17.82

Finally, the FilterMag company itself has an interesting (30-page) PDF document available for downloading at the following web site (click on the link “Filtermag Tech Brochure *NEW*” at the top of the web page):


I’d attach the document, but I don’t believe I have the proper forum privileges to do so, or to send a personal message to you with the attachment. (Very silly forum rules, in my opinion.)


07-20-09, 05:59 AM
Kyle, excellent info, I added it to ctsvparts.


07-20-09, 06:19 AM
I wonder if anyone who is going to put one in the diff can take a photo so I can see where to place the dang thing.

07-20-09, 06:19 AM
Thanks Kyle, it looks like I've identified my supplier.

Where does one put the transmission magnet? Just curious as the concept of using magnets in this application is new to me still.

07-20-09, 06:26 AM
Think it just goes on the pan, nothing special necessarily.

07-20-09, 06:40 PM
Guys: To clarify some of your questions (e.g., location of magnet inside the differential) and answer some additional questions of my own, this afternoon I put in a call to FilterMag. Unfortunately, the technical expert at FilterMag is away on business, but will call me back either later today or tomorrow morning. So I’ll post more information after I’ve talked with him.

In the meantime, anonfrank, I can answer your question regarding where to place the external magnet for the transmission. Put it on the same level as the transmission drain plug, given that this location is “higher” off the ground, and therefore guards against anything knocking the magnet off the pan (as will become obvious, if you look at the undercarriage of the V when it is on a lift).

When a car repair shop I stopped at to have the engine oil filter and transmission magnets installed (I won’t install the internal differential magnet until I change my differential fluid at 1,000 miles or so) put my V on a lift, they thought that the transmission might have a magnet in the drain plug. But the FilterMag transmission magnet is certainly much stronger. Indeed, the mechanics were very impressed with how strong the magnet was. But at 25 lbs. of force the FilterMag transmission magnet is still considerably weaker than the “racing” (RA) version of the FilterMag engine oil filter magnet – which has 300 lbs. of force. So even if you replace the factory-installed non-magnetic drain plug in the V’s engine oil pan with the “Vette” magnetic drain plug (as it’s my understanding one can do), the FilterMag engine oil filter magnet is going to be far stronger and should therefore collect metal shavings far better than the Vette’s magnetic engine oil drain plug.


07-21-09, 06:59 PM
I remember when domestic auto mfg's would put a magnet in the tranny pan at the factory. :rolleyes:

07-21-09, 10:04 PM
Thanks again for the information!

Looking forward to this mod as I'm hopeful it will extend the life of the engine. I wish I had thought of using it on other cars.

07-24-09, 11:05 PM
Guys: Sorry about the delay in posting the remaining information regarding FilterMag products that I promised you on my last post. I have talked twice now with Bob Fowler (800-345-8376, bfowler@filtermag.com), who is the (very well informed) tech rep for FilterMag (and an extremely nice guy).

SlvrBullIT: [Where to place the internal differential magnet?] Bob notes that there is a cover on the differential that is always removed when changing the differential fluid; so just place the internal magnet (i.e., DM-101) at the lowest point in the differential housing (and away from moving parts). At the next fluid change, mechanics will always clean out the differential housing, so the magnet can be removed during cleaning, and then placed back into position after the hosing is cleaned.

A friend of mine (who races his Vette extensively) told me recently that he thought differentials had an internal magnet. Bob told me he had not seen such magnets installed in differentials, but if some manufacturers did include a magnet, it almost certainly would be a much less expensive “ceramic magnet,” which is far less powerful than the differential magnet FilterMag sells. I also asked Bob if one could use the TM series external transmission magnets for internal installation in the differential. But he responded that the (smaller) TM-180 transmission magnet has the same magnetic pulling power as the DM-101 differential magnet, and that the (larger) TM-360 transmission magnet is simply two TM-180 magnets combined into a single package. However, because of its larger size, the TM-360 magnet might be difficult to fit inside the differential – and, in any case, that it would likely be “over-kill” with regard to any advantages over the DM-101 magnet in filtering differential metal particles.

1BlinkGone: You posted that you can “remember when domestic auto mfg's would put a magnet in the tranny pan at the factory.” Bob says that many manufacturers still do use internal transmission magnets. But these are (cheaper) “ceramic” magnets with probably 1/10 or less the pulling power of the FilterMag (TM) external transmission magnets.

Also, in my last post on this FliterMag thread, I noted that a FilterMag sales rep had told me that the (smaller) TM-180 external transmission magnet was fine for cars, and that the (larger) TM-360 magnet is generally used on big trucks. Bob noted that an additional reason for this suggestion to use the weaker of their two transmission magnets on cars is that they have found (though very rarely) that their transmission magnets are so strong that they will affect the servo valve operation of the transmission. However, he noted that the (more powerful) TM-360 magnet could potentially provide additional protection in situations (such as racing or heavy towing applications) where the car transmission might be subjected to exceptional stress. Under these circumstances, just be careful to place the magnet away from servo valves. So does any forum member know where the servo valve mechanisms are located in the V’s transmission?

A few other points that Bob discussed with me: In the installation booklet that come with the FilterMags, the TM (transmission)-series instructions say: “Don’t clean the outside of the fluid pan with harsh cleaners that may damage the TM label.” But Bob noted that these “harsh cleaners” do not affect the operation of the magnets. The warning is simply so mechanics will be able to read the label for purposes of identifying what is on the transmission pan. Also, the next instruction says: “After fluid pan removal, thoroughly clean the inside of the fluid pan to remove particles caught by the TM.” But Bob says some manufacturers do not recommend removing the pan when changing the transmission fluid. Under these circumstances, as long as mechanics don’t remove the TM magnet attached to the pan, the particles will still be trapped, and therefore will not start circulating when the transmission is refilled with fluid. However, he notes that you might still want to drop the pan just to see if a large number of particles have accumulated – which would be a good “diagnostic” that the transmission was undergoing excessive wear.

I think there might be some confusion over different versions of the various magnets that FilterMag sells (e.g., the 30-page document lists parts numbers that you will not find at some web sites selling FilterMags). Bob confirmed that GP-101 & DM-101 differential magnets are same product. Also, the “HP-Pan” transmission magnet has a pulling force somewhat lower than the TM-360 but greater than the TM-180; and the “SS-Pan” (both the red & the black color version) is a bit weaker than the TM-180.

As a last point, FilterMag has a magnet for diesel fuel filters. (I believe it’s the same one they use for oil filters, which would be specific to the diameter size of the fuel filter.) I asked Bob why they don’t have a magnet for gas filters, and he said there are not sufficient metal particles in gas to justify using a FilterMag. But for those of you who have diesel engines in your RVs, you might want to consider this additional protection available from FilterMag.

Bob Fowler has asked me to email him the link to this Caddy forum thread, which I will do shortly so that he can check to make sure what I’ve told you here is an accurate reflection of what he told me.