View Full Version : mega vs. cat
WOULD LIKE TO ADD 2ND FUEL FILTER,I HAVE BEEN READING ALOT OF POST HERE AND DON'T KNOW WHICH WAY TO GO ,SOME SEAM TO GET ALOT OF AIR IN SYSTEM,SOME PLACED BEFORE OEM SOME AFTER,DIFFERENT BRANDS? CAT FILTER BETWEEN TANK AND OEM FILTER SEAMS TO BE WORKING?
Mine works. See my signature.
Victory Red
07-08-2003, 16:45
Anyone one of the 3 will do you just fine. Just that 2 of the 3 have prime loss issues in some circumstances.
My Cat post oem has a few issues. I troubleshot it a little this weekend and found something interesting. Until I get a little more time to play I'm not screaming a fix for it yet.
My prime loss seems to be between the out line of the OEM to the in line of the secondary. Still working on a simple solution for this shy of a lift pump. :D
gene smith
07-09-2003, 19:38
ok im lost-cat is 2 micron---o.e.m. 1 micron---should the cat be before or after the oem, also what brand lift pump is most dependable with no more than 1/2 lb of pressure but high volume an do i need to carry one of them as a spare. thanks--Geno
[ 07-09-2003, 07:44 PM: Message edited by: gene smith ]
Jack's Dmax
07-10-2003, 01:37
Where to install the filter is a matter of opinion. I chose to install my Cat 2-Micron filter pre-oem because of the reliability. To the best of my knowledge, no one has reported problems with air in their pre-oem installation, and a lift pump is not needed.
The additional plus for me is the ease of changing the Cat filter. It is located below the fuel filler in the wheel well. Use search for ndamico, he has posted pictures of his install in the recent past. My system is the same as his. The replacement Cat filter is $18.00 for the long version.
Good luck with your decision,
Jack
For those who chose to to pre OEM, I had a few questions:
1. How do you cut the metal fuel line? After cutting does the fuel begin to siphon out of the tank?
2. When chainging a filter mounted pre-OEM, does the fuel from the tank again siphon out while swapping filters (in other words, is it a pain in the rear to change)?
3. Since there is no water separator in the CAT filter, does the water go through until it hits the separater in the OEM filter?
Thanks! These filter discussions have been great reading. :D
[ 07-10-2003, 08:34 AM: Message edited by: roegs ]
I used a small wheel tubing cutter designed for tight spaces.Any hardware store should have one and not very spendy. smile.gif
Yes fuel does siphon out of the tank at a a rapid rate so have your plug or piece of hose with a bolt in it at the ready(like I had to find as fuel was draining everywhere). :eek:
Even though I have a post oem Mega I cut into the hardline to install a lift pump. :D
FWIW, I haven't heard of any (not saying there haven't been issues) air lock issues with an aux. filter installed PRE OEM. I'm sure that ther have been some, just like the OE unit can have difficulties in some cases.
I believe that this is due to the fact that the OE filter has a check valve in it. Having a place for air to accumulate will allow the fuel to drain back and air to rise into the suction hose. I have a check valve in testing that will likely be available shortly....
That said, I still feel that same way:
Free gasses in fuel is not desireable.
Secondary filtering is the better alternative when using a fine element.
Residence time (flow rate through filter media) can have a profound effect on efficiency.
Filters perform much better under pressure than vacuum.
A fuel lift pump is a good thing. The suction required to draw the fuel from the tank can be quite excessive at times!
Another option for plumbing in a pre-OEM filter is to remove the OEM fuel hose (http://community.webshots.com/photo/67970835/72256041LaCXPA) between the tank sender and steel line behind the fuel cooler. The added pre-OEM filter can then be plumbed in (http://community.webshots.com/photo/77018086/78005228CHjpzK) using 7/16 ID fuel hose and hose clamps. The 7/16 hose fits tightly to the tank sender nipple and steel line (a bear method). This would make the setup completely reversible. The down side is that to gain access to the sender, the tank has to dropped or a slot cut (http://community.webshots.com/photo/67970835/72255641wBdYMf) into the tank shield (http://community.webshots.com/photo/67970835/72257196KTCvMU). smile.gif
i removed the same line as jpblock. 3k+ miles and no problems yet. i'm installing another setup tonight for another DP member and after looking i think i can get over the tank shield so i won't have to cut it. with my transferflow tank i just sat up underneath the truck and looked at the top of the tank. i can get my arms/eyes around the shield w/o cutting.
also when i did mine, fuel didn't continue to pour out once the lines were disconnected..
chuntag95
07-10-2003, 15:27
I replaced the line to the tank like Bill and took a bath in fuel. I put at least 1/2 gal on the ground when my catch can filled up. Need to work faster or have a plug ready. I didn't think I would ever stop smelling fuel. :rolleyes:
GM Smitty
07-10-2003, 15:30
With a full tank of fuel, it will continue to siphon out (my experience). I installed a shut off valve to keep this from happening. I didn't install the valve at first, just figured I'd change the filter when the tank was less than 1/2 full...but then realized my filter would probably clog right after I filled up. :rolleyes:
DURA-MAX3
07-10-2003, 16:02
I installed my Cat filter pre-oem and have had no problems with air or needed to add a lift pump. I am at 5000 miles on the short filter and just bought a new one for 10.49. That is cheaper than the factory filter. I have listed on here somewhere all the parts and numbers for the Cat install pre-oem. CCDS and i have the same set-up and have had no trouble at all. Install takes about a hour and half. Run your tank as low on fuel as possible and park the truck up hill if possible to keep the fuel from siphoning out as bad. I went pre-oem because it goes through the factory filter last and that is the safest way my dealer said to keep Gm from holloring warranty crap. That is a headache i don't want...
Jim Cobler
07-10-2003, 17:00
I installed my pre-filter/water separator on the frame rail and put a ball valve on each side of it.
When you change the filter, you turn off the valves, open the water drain in bottom with a drain pan under it, and loosen the filter. As soon as you break the seal, the fuel will run into the pan.
It is simple, it works and you don't bathe in diesel fuel.
D'Max_2_DA_Max
07-10-2003, 19:10
Jim Cobler,
You mention Pre filter and water separator. Most of the posts I've seen don't seem to include the water separator. What brand/model filter are you using? Does it include the water separator? :cool: :cool:
Jim Cobler
07-10-2003, 20:09
I use a Baldwin BF 1213 Fuel/Water separator with a drain which I believe is a 6 micron.
Every professional filter person I have talked to universally agreed the pre-filer should be a water separator.
SO WHAT IS THE ADVANTAGE OF POST OVER PRE MOUNT? DOE'S ONE WORK BETTER FILTERING THEN THE OTHER,THANKS MIKE
The OEM filter does not do a very good job due to laboratory standard testing they used to qualify it.
The word is they used clean fuel in testing and they didn't account for real world situations such as dirty American fuel and the engine induced vibrations that agitate the particles through the filter.
The bad news is filtration specs supplied by most filter manufacturers are based on similar "controlled" envirionments. Doesn't do the end user much good when a filter is 98% effective in a lab but drops to 50% in the real world.
To answer the post/pre question..
It makes more sense to install a tighter filter after a looser one. The loose one catches the big pieces and the water first. Than you refine the fuel with the low micron media.
The second filter will last longer too.
[ 07-11-2003, 11:39 AM: Message edited by: hoot ]
It's still early, but here is a comprehensive list of the problems I've had with my pre-OEM Cat fuel filter since installation: 0
The weather has been miserably hot, as high as 107 Friday. The truck didn't seem to notice, though now I'm joining the chorus of those dissatisfied with the strength of the air conditioner. My old 4Runners, even the wimpy four banger had better AC.
TC
TC,
I've completed the next stage of brackets too. I am having them stamped out of 1/4 steel and then folded. no more welding and looks much cleaner as one piece.
Is anyone else local to the sacramento area and looking for a pre-oem CAT filter setup? i'd like to find someone with a long bed.
Hi, Nick, the truck purrs like a kitten.
Anyone interested in this type of setup ought to take Ndamico up on his offer. He is pretty much singlehandedly keeping the Sacramento area Duramax fleet upgraded to the latest standards and is a wealth of information, generously shared. This is not his line of work. He just does it because . . . well, I don't know why, but I sure appreciate it.
TC
Maybe Nick is just looking for a better flashlight apprentice. Or maybe he needs help with a speedin ticket :D Either way- glad you'all are sharing the info!
Am still fixing to go JK system when the time's right. Have a good summer.
zip
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