View Full Version : Problems with new low sulfur diesel?
Jeff in N.Tx.
08-28-2006, 03:18 PM
I have heard a lot of stories about how the new low sulfur diesel will cause damage to injector systems in our current Cummins, and Powerstroke engines.
Is this true? Also, I have been told the lower sulfur content decreases lubrication, and that we should run some type of additive to protect our engines. If all this is true, then, what type of additive should I run in my diesel pickups? Thanks.
Jeff
warlock440
08-28-2006, 07:14 PM
the sulfer in the diesel act as a lubricant for the pump.. there are additives which help the lubricity of diesel to help the older injection pumps survive or the can be rebuilt with new internals to last with the new ULSD fuel.. Personally with my older Diesel(93) I will run it til it quits then have the new internals put in but that may take awhile since I have an 06 that is now my DD..
MoparNorm
08-28-2006, 08:12 PM
Low sulfur and ultra low sulfur have been the only diesel available in CA, since June. So far, no apparent side effects. I've searched the Cummins and oil industry web sites, they all claim that there is no known side effects from the new formulas, after much testing. Cummins does hedge their bets by saying that there is no "known" issues, but the time frame for testing was only two years.
I'm a firm believer that additives are pretty much wallet depleters with no or little advantages.
The main areas of concern appear to be seals and o-ring life, not engine wear.
MN
warlock440
08-28-2006, 10:22 PM
I'm a firm believer that additives are pretty much wallet depleters with no or little advantages.
The main areas of concern appear to be seals and o-ring life, not engine wear.
MN
you are correct since the distributors are already adding the additives to bring the ULSD lubricity up to standards.. This info is on the Tosco(Conocophillips) and BP sites.. Also WSU has an article which if you read it has the following statement under "OTHER ISSUES"
"This reduced lubricity could result in exessive engine wear without the addition of a high lubricity additive,like biodiesel"
MoparNorm since you are the all knowing God who has to see stuff for yourself to believe it here is tha address to go read it for yourself..
http://www.energy.wsu.edu/ftp-ep/pubs/renewables/Fuels.pdfr#search='ultra%20low%20sulfur%20diesel%2 0lubricity'
hope you can read.
Sickcall
08-29-2006, 05:37 AM
I read today in the paper where ULSD will be at the pump in Calif starting Friday. Is this for off road fuel also?
JimmieD
08-29-2006, 06:51 AM
There are several issues regarding diesel fuel that cause many owners to use additives. To prevent algae, increase cetane rating, add lubricity, prevent cold weather gelling of fuel, or to cause water in fuel to blend harmlessly many use products like Power Service etc. The owner's geographic location or where you travel to can have an effect due to weather changes and available local fuels. From what I've heard the stuff pays for itself [at least Power Service] and is good insurance, low sulphur or not. I plan to use it every tankful when I get my truck finished and on the road especially now that the fuels have been changed.
warlock440
08-29-2006, 09:10 AM
I read today in the paper where ULSD will be at the pump in Calif starting Friday. Is this for off road fuel also?
Sickcall
All the diesel leaving the refineries will be ULSD,however, during the shipping and storage process the diesel picks up residual sulfer.. The residual sulfer has the potential to raise the sulfur above the 15 ppm(parts per million) allowed.. The Distributor is responsible for making sure that the fuel it delivers for on road use is at or below the 15 ppm and can be fined several thousand dollars(IIRC it is around $32000)..If the fuel goes above the 15 ppm they have two options..Option #1 is to send the fuel back to be rerun to remove the excess sulfur.. the down side to this is the expense because you have to pay to have it shipped back to the refinery and then you have to run it back through when you could be making new fuel.. the second option is to sell it as offroad fuel which is cheaper quicker and easier for the Distributor..
By the way you have had the ULSD for several months now.. They have changed the stickers now that the fuel coming out of the pump has been tested by the EPA and found to be below the allowed 15ppm..
MoparNorm
08-29-2006, 12:48 PM
Sickcall more than likely did not read my post before posting. However he may be in an area that had a later "phase-in date". Depending upon the Pollution Control District in CA, the phase-in dates were/are, June 1, Sept. 1 and a date in Oct. either the first or 15th, I can't remember at the moment.
Warlock, Thanks for your concern about my reading ability, however the link does not work....= )
Because there are several dates in CA and several more in the rest of the nation, going all the way into next summer, auto manufacturers have been in no hurry to rush the new diesels to market. Using the wrong fuel will kill the active scrubber in the new cats in the 2007 models. Because of that you will see some models not offered at all in 2007 and the ones that will be offered will be 45 state only (CA and 3 northeastern states and Minn. have the same regs.) The true 50 state legal clean diesels won't be seen until 2008. Even VW with it's 55 mpg super diesel is staying away from the CA market until 2008. Confusing gov. regulations, delayed testing and inconsistient fuel phasing will disrupt the free market for a spell and cause us to use more fuel and run dirtier, all because of "clean air" regs, ironic isn't it.
MN
Charles Talbert
08-29-2006, 01:17 PM
Injector pumps with rotary type heads like the ones on the multi-fuel engines in the M35A2 military trucks, the older stanadyne rotary pumps found on 60's models John Deere engines, etc. suffer the worst from the lack of lubrication because of the rotary design. These type pumps definitely need something added to replace the lost lubrication.
Sickcall
08-30-2006, 02:31 PM
The correct time line mandated for the phase in of ULSD diesel in CA was/is;
Refinery Jun 01, 06
Terminal July 15, 06
Retail Sept 01, 06
Locomotive/Marine Jan 01, 07
As CA is mandating a tighter timeline for introduction of ULSD and have mandated ULSD for both on and off hiway fuels, the EPA has exempted CA from labeling its retail fuel pumps.
Being a CA resident that is what I was most concerned about, but the rest of the folks in the good ole' US you can check the below site for correct information;
http://www.chevron.com/products/prodserv/fuels/diesel/ulsd.shtml
It appears most people are concerned with the negative effects of ULSD, but I wonder what the positive's will be. I have burned many marine grade fuels (BFO's, IFO's, MDO's) delivered from refineries around the world and can tell you that next to heavy metals, sulfur is very damaging. As a by-product of combustion, combined with water, it forms Hydrosulfuric acid in the various exhaust systems and uptakes. It does not take long for this caustic corrosion to start eating away and damaging equipment, beginning right at the exhaust valves. (The same as acid rain but right in your exhaust pipe.)
Optimistic yes, but we will probably have to wait for the next round of lawsuits to settle before we know the truth.
MoparNorm
08-30-2006, 09:52 PM
It's been available here in the SCAQMD regulated area since June. Too soon to have any effects on wear, but I also haven't noticed any change in mileage or power. Our pumps are stickered, but I assume that as of Sept. 1st the stickers will come off as ALL fuel will be the ULSD.
MN
MoparNorm
09-01-2006, 09:01 PM
I was reading an article in 'Off Road Adventures' yesterday, which came the same day as the PWA! What a great mail day!
The article states that while CA has full emplimentation of the ULSD by Sept.1 (today). that some parts of the US are not going to go to full ULSD until 2010. That is going to be a real pain for cross country diesel drivers and perhaps why the manufacturers are not in a hurry to rush out new diesel motors for the "Gang of 5*". The article also states that the new diesels must run low sulfur OIL as well to be compliant, the new oil APA rating is CJ4, if you have a new diesel, no other oil is compliant and older ratings such as SF/CD will harm the emission systems.
MN
* The Gang of 5 is CA and four other states that follow CA AQMD requirements.
JimmieD
09-02-2006, 12:04 AM
I was reading an article in 'Off Road Adventures' yesterday, which came the same day as the PWA! What a great mail day!
The article states that while CA has full emplimentation of the ULSD by Sept.1 (today). that some parts of the US are not going to go to full ULSD until 2010. That is going to be a real pain for cross country diesel drivers and perhaps why the manufacturers are not in a hurry to rush out new diesel motors for the "Gang of 5*". The article also states that the new diesels must run low sulfur OIL as well to be compliant, the new oil APA rating is CJ4, if you have a new diesel, no other oil is compliant and older ratings such as SF/CD will harm the emission systems.
MN
* The Gang of 5 is CA and four other states that follow CA AQMD requirements.
As I will soon be a cross country diesel driver what's the '...real pain..." part, Norm!?! I have read of a lot of guys using the new fuel with no problems so far, but is there something I missed, or maybe you already mentioned it? To be forewarned is to forearmed or something like that.... Anyways, Boy Scouts stuff: Be Prepared, so what's the straight scoop?
MoparNorm
09-03-2006, 12:21 PM
You are fine. What I was referring too, is this; if you have a ULSD diesel motor in a 2007 vehicle, and you drive into a state that is not adopting the fuel regs until 2010, you are basically screwed. Where are you going to find fuel? That explains why Detroit has been in no hurry to rush the new motors to market in the gang of five states. Can you imagine buying a new Ram with the Cummins in CA and not being able to travel out of state? I'm looking to see if I can find a state by state list. In the meantime, unless you have a 2007 ULSD diesel, don't worry about it.
MN
JimmieD
09-03-2006, 01:16 PM
Thanks, Norm. I did quite a bit of reading on several sites regarding ULSD and the common consensus is to use a lubricating additive. The early Cummins uses a rotary pump, the Bosch VE, which requires the fuel to lubricate it as Paul mentioned. Lots of products available from many companies to add lubricity.
BTW several folks have come to the conclusion that the whole ULSD thing is also yet another attempt to remove older vehicles from the roads. The known lack of lubricity and complete failure to make ANY ATTEMPT TO REPLACE IT points to a rather ugly intent on the part of those involved in the whole scenario. Remove the pollutions and remove the rattle trap polluters and get the bonus of folks having to pay much higher sales tax and fees when buying their newer replacement vehicle! Hmmm, would some folks willfully do such a thing? Answer: THEY HAVE! Just like crushing all the older vehicles in wrecking yards in CA......
Sickcall
09-03-2006, 02:57 PM
Norm, as usual the regs are long and very misleading. From all the web sites I have checked, even after the EPA 45 day 49 state extension, all retail pumps will dispense ULSD after Oct 15th, 50 state. The phase in of the 80/20 ratio for refiners until 2010 is for non road fuel, NRLM. After visiting a dozen web sites I think it will be OK for the fifth wheel crowd to trailer out of state.
After the lubrication replacements hit the shelves this would be a great place to do a comparison (opinion) testing. What do ya think?
JimmieD
09-03-2006, 04:20 PM
Norm, as usual the regs are long and very misleading. From all the web sites I have checked, even after the EPA 45 day 49 state extension, all retail pumps will dispense ULSD after Oct 15th, 50 state. The phase in of the 80/20 ratio for refiners until 2010 is for non road fuel, NRLM. After visiting a dozen web sites I think it will be OK for the fifth wheel crowd to trailer out of state.
After the lubrication replacements hit the shelves this would be a great place to do a comparison (opinion) testing. What do ya think?
The lubricity enhancers have been out there for years. Power Service, Stanadyne, Amsoil, and MANY others are already available. Diesel has some problems that gasoline doesn't share so these products are made to solve those deisel specific issues. Some of these like Power Service add to the cetane rating of fuel, giving better thermal dynamics and efficiency, thereby paying for themselves! There are those who run diesels without additives but the majority of owners are pro-additive due to diesel's peculiarities.
Sickcall
09-03-2006, 07:01 PM
Jimmie, I don't think I would agree with that statement, that the majority of diesel owners already use these additives. I am assuming you are talking about us small timel truck owners and not the fleet owners of big rigs. I am not, nor anyone I know, presently using a diesel additive. My observation is that they do not appear to be in common use. When I'm at the auto store or the fuel station, diesel additives don't appear to be well stocked on the shelf. One thing that is certain is that more people will begin to use them and I though a little dialog on the subject would be helpful, at least to me.
I am a licensed chief engineer of US flag vessels that use diesel engines for main propulsion, unlimited horse power. Our diesels burn both residual and refined diesel fuels and each loading of fuel is checked for various specifications onboard in our own small fuel lab. I doubt most people understand what the cetane index rating of their fuel has to do with combustion. I bet very few even know the cetane rating of the fuel their buying at the pump, the vehicle manufacturers recommendation,or how much additive to use that raises the cetane rating to what value? To just raise the cetane index rating to a level that slows cylinder combustion can be a bad thing. or too much of a good thing.
Even adding too much lubrication to diesel can be harmful. We used to get marine diesel oils cut with lube oils years ago and we would foul rings, score cylinder liners, and put out the prettiest blue smoke. Fortunately today not much of this is happening through industry self-regulation. Having spent 30 years centrifuging and filtering fuels I can tell many horror stories of what a bad load of fuel can do.
Today we use additives, or snake oils as we call them, either iron or magnesium into the fuel to combat vanadium and salt slags. I have been spending $10,000 a month on these additives and requisition them by the drum. Some are entered into the fuel tanks and some are meter injected into the fuel lines.
I do think that additives may become necessary with this new blend and I myself will be doing more research. I have to cut the bank teller note short here, I thought it helpful to know what others have been or will be using. Lets just say bring on the juice.....
JimmieD
09-04-2006, 12:03 AM
Yes, it's a case of comparing apples, oranges and maybe pears. Over the road fleet diesel use, fleet marine diesel and personal light truck diesels are decidedly different. When I speak of the majority I mean those personal use light truck diesels, with this information gotten off of several diesel forums. The question of additives comes up often and of the percentage that respond it seems that about 75% use an additive of some kind or another. This may be one of the additives from the many synthetic oil dealers, or other diesel specific products from companies specializing in diesel additives like Stanadyne or Power Service or others. I can't say it's spoken from personal experience, but only as a comment reflecting the many replies of those posting on diesel forums.
Under the best of circumstances there are potential problems with diesel fuel itself even before it is fueling a vehicle. Water, algae etc. can cause storage problems, and cold temperatures cause gelling to name a few. Many owners choose the products like Power Service to protect their fuel and truck investment. The additional bonus of a cetane boost (2-3 points) can help to offset the cost of some additives by its mileage and performance improvement.
My own plans are for an additive in every tank, probably Power Service or Amsoil, plus water and methanol injection. These last are to overcome certain problems when turning up the fuel delivery such as elevated EGT's which are the by-product of that performance increase. Here the methanol restores some power lost by the water injection's quench effect and the Power Service adds a cetane boost while protecting fuel and adding lubricating properties. Therefore I can delve into some heavier fueling and run the turbo [s] at the limits as well. The overall package is just what I need, especially with the new ULSD. With a stock engine as delivered by the manufacturer this may be seen as unnecessary, and especially a marine engine for fleet use, where such a combination would probably only give a little more velocity as the cylinder heads launch through the lower decks.
I see it all as very application specific and a matter of personal choice. Some are of the same opinion as I am, while others are not... :~ )
Here's a link to Power Service website main page in case you want to peruse their offerings. Obviously geared to something other than fleet marine yet boasting considerable merit. User's reports back up the manufacturer's claims from what I've seen.
http://www.powerservice.com/
MoparNorm
09-05-2006, 11:49 PM
I've been out of town for a few days, here are the dates from the Clean Diesel Fuel Alliance website and 2010 is indeed a highway fuel date in the 45 states.
"Effective Dates for Highway ULSD Fuel
Who What
Refiners & Importers
Import/produce at least 80% ULSD for on highway use
California 6/01/06
Import/produce at least 100% ULSD for on highway use
U.S. 6/01/10 California 9/01/06
Downstream from Refineries through Fuel Terminals
Facilities that choose to carry ULSD must meet 15 ppm sulfur specification CA 9/01/06
All US highway diesel must be ULSD 10/01/10
Retail Outlets Facilities that choose to carry ULSD must meet 15 ppm sulfur specification 10/15/06
All highway diesel must be ULSD US 12/01/10 CA 9/01/06
Although ULSD fuel will be the dominant highway diesel fuel produced, EPA does not require service stations and truck stops to sell ULSD fuel. Therefore, it is possible that ULSD fuel might not be available initially at every service station or truck stop and that a diesel retailer may choose to sell Low Sulfur Diesel fuel instead of ULSD fuel. The industries involved in the transition are doing all they can to minimize potential inconveniences during the conversion to the new diesel fuel."
MN
MoparNorm
09-08-2006, 08:55 PM
The Clean Diesel alliance website has a FAQ section: http://www.clean-diesel.org/faqs.html
Among the questions are these two:
Q. Will ULSD fuel affect the performance of my vehicle?
A. Engine and vehicle manufacturers expect ULSD fuel to be fully compatible with the existing fleet, including 2006 and earlier model year vehicles. In some instances, the introduction of ULSD fuel to older vehicles may affect fuel system components or loosen deposits in fuel tanks. As part of a good maintenance program, owners and operators of existing cars, trucks and buses are encouraged to monitor their diesel-powered vehicles closely for potential fuel system leaks or premature fuel filter plugging during the change-over to ULSD fuel.
Q. Will I need to put an additive in my fuel tank to replace the lubricity that was provided by the higher sulfur content?
A. Like Low Sulfur Diesel fuel, ULSD fuel requires good lubricity and corrosion inhibitors to prevent unacceptable engine wear. As necessary, additives to increase lubricity and to inhibit corrosion will be added to ULSD fuel prior to its retail sale. With these additives, ULSD fuel is expected to perform as well as Low Sulfur Diesel fuel.
I thought that might put to rest some of the misgivings expressed here and eliminate people running out and buying expensive but unrequired additives.
MN
JimmieD
09-09-2006, 07:40 AM
Thanks, Norm. I think a lot of this additive questions depends on what diesel we're talking about. In my case it's a Cummins 4BT, an engine that uses Bosch VE fuel injection in which the fuel provides the sole lubrication for the injector pump. They're not cheap to replace and impossible to rebuild at home. My advisors for the 4BT swap and diesel tech have encouraged the use of Power Service products or other additives to provide increased lubrication, and this even before the introduction of ULSD.
In the SoCal and other southern areas with warm temperatures and low humidity plus a high rate of turnover of diesel product there might be few problems. In other parts of the country winter weather and temperatures play a key part in degrading fuel. The additives prevent gelling in cold weather and help a lot with quick starting in winter. They prevent algae from forming in fuel and help to manage any water content, plus they assist in the cleaning of the fuel system. Just like Marvel Mystery oil, a good bit of extra insurance. Though an additive may just be money out the exhaust in a later engine it seems to be a good idea to use in an oldie. From firsthand reports the Diesel Klean and others pay for themselves thanks to the cetane boost and other advantages. So in my own specific case: additives are the way to go for peace of mind. Others might have no problems at all..... :~ )
steved
09-20-2006, 01:29 PM
As most of you have noted, ULSD must meet an ASTM standard for lubrication, it will work in older diesel engines without harm. It "should" be no less lubricating than the LSD we currently run.
And I seem to remember that sulfur is not a lubricant, it is a "contaminant" in diesel that is hard to remove...you don't really need it for operation, and the reason it was left in the fuel was it was costly to remove (and added an extra step to the refining process).
And most of you don't realize you have been getting ULSD for a while...we have had it in PA for well over 6 months now...that super green colored fuel you now pump is typically ULSD. They can't mark the pumps as ULSD until so much ULSD has been through the system to "purge" the LSD...and not every refinery has switched...
I only have two concerns about LSD, and neither are lubrication related:
The first is the fact that ULSD affects older seals (it either "dries" them out or makes them swell depending on material). Guys with older 6BTs are already seeing the orings on their fuel filters and fittings swelling up...just like biodiesel.
The second is that not unlike biodiesel, ULSD super cleans fuel systems. And while this might not sound like a bad thing, it super cleans the storage tanks, the tank truck, the inground tanks, all the fuel lines in between, and finally your fuel system. So you could potentially get at the least a plugged filter. I have heard of a few plugged filters, but no major system failures...
steved
MoparNorm
09-20-2006, 06:38 PM
Hi Steved,
Yep, noted in my post #21, the link in that post has a few more issues and things to watch out for in order to prevent unneeded repairs. I've gone about 11,000 miles now using ULSD, so far, so good.
MN
Saraguay
09-27-2006, 08:26 AM
As an introduction, I haul and deliver fuel in the Southeast and we have been very involved in the testing and implementtion of ULSD. When I say deliver, we have delivered maybe 300,000,000 (yes, three hundred million) gallons of ULSD so far this year.
The biggest concern by the refineries and terminals was that there would be a lack of lubricity in the product, causing fires in tankers and at the pumps.
S, yes, as mentioned in other posts, they are adding lubricity agents at the terminals as we load the trucks.
I am not a scientist nor an engineer, but I own over 20 big trucks and run fuel that operate several thousand throughout the Southeast and all over America.
We have seen no problems at all. There have been a few complaints of engines running hotter but that is idle gossip from 3rd parties. To date, there is no eveidence to suggest any issues.
JimmieD
09-27-2006, 09:19 AM
Thanks for adding that, Saraquay! In thinking about it I will be using lubrication throughout the life of my one vehicle because it's a 4BT with fuel pump lubricated by fuel. However others with different powerplants might want to follow another protocol. Seems that until all the data is in and many miles have been logged in these other vehicles that a guy might want to use an additive for safety's sake. Then if the general concensus is that it is prefectly safe afterall a fellow can make the decision whether or not to run straight diesel? Just my thoughts on it....
Tech Tim
09-27-2006, 01:22 PM
The lubricity enhancers have been out there for years. Power Service, Stanadyne, Amsoil, and MANY others are already available. Diesel has some problems that gasoline doesn't share so these products are made to solve those deisel specific issues. Some of these like Power Service add to the cetane rating of fuel, giving better thermal dynamics and efficiency, thereby paying for themselves! There are those who run diesels without additives but the majority of owners are pro-additive due to diesel's peculiarities.
Be careful with any additives, many of them do not add lubricity and will tend to dry out seals. Make sure whichever one you use, it says on the bottle that it adds lubricity.
I like Howes diesel lube, but there are other decent brands out there. ANother one is Lucas.
steved
09-27-2006, 09:15 PM
Be careful with any additives, many of them do not add lubricity and will tend to dry out seals. Make sure whichever one you use, it says on the bottle that it adds lubricity.
I like Howes diesel lube, but there are other decent brands out there. ANother one is Lucas.
The main thing with additives is to ensure whatever you use doesn't contain alcohol...from my experience and readings, the top additives used are Power Service, Marvel Mystery Oil, Stanadyne, Howes, and Lucas...Amsoil is only now starting to really push their new stuff...
I personnally have logged over 200k on a 99 ram running Power Service, a little bit of Howes and Lucas...but primarily PS. I currently have almost 95k on my 2004.5 and run almost exclusively Howe's (either the meaner power cleaner or the diesel treat)...
One thing you ALSO got to keep in mind is these newer CRDs are more prone to contamination, it isn't just lubrication issues...DCX used 10 micron filters in the 3rd gen dodge rams with the CRD CTD until only recently when they switched to 7 micron. Bosch (the company that makes the injection system on most CRDs, and does make the system on the CTD and Duramax, and I believe the new Fords now) states to run a minimum of 5 microns and would prefer a 3 micron filter...hmm, then why is DX pushing 7's?? I am currently running a FASS with filters that are rated 99.5% @5 micron, 98.6% @ 3 micron (absolute), and 95% at 1 micron...just because DCX sucks.
steved
Tech Tim
09-27-2006, 11:40 PM
The main thing with additives is to ensure whatever you use doesn't contain alcohol...from my experience and readings, the top additives used are Power Service, Marvel Mystery Oil, Stanadyne, Howes, and Lucas...Amsoil is only now starting to really push their new stuff...
And make sure you follow the directions on the bottle. Some of the mentioned additives, you do not want to add more than the reccomended dose. That's one thing I like about the Howes is you can't overtreat.
I personnally have logged over 200k on a 99 ram running Power Service, a little bit of Howes and Lucas...but primarily PS. I currently have almost 95k on my 2004.5 and run almost exclusively Howe's (either the meaner power cleaner or the diesel treat)...
Yep, take care of the truck and it'll take care of you. I've just turned 210K on my Powerstroke and have used Howes almost exclusively.
One thing you ALSO got to keep in mind is these newer CRDs are more prone to contamination, it isn't just lubrication issues...DCX used 10 micron filters in the 3rd gen dodge rams with the CRD CTD until only recently when they switched to 7 micron. Bosch (the company that makes the injection system on most CRDs, and does make the system on the CTD and Duramax, and I believe the new Fords now) states to run a minimum of 5 microns and would prefer a 3 micron filter...hmm, then why is DX pushing 7's?? I am currently running a FASS with filters that are rated 99.5% @5 micron, 98.6% @ 3 micron (absolute), and 95% at 1 micron...just because DCX sucks. - steved
Add in a Racor filter set-up as a secondary. You can choose different micron filters and have the awesome Racor water seperating capabilities.
steved
09-28-2006, 08:08 AM
Add in a Racor filter set-up as a secondary. You can choose different micron filters and have the awesome Racor water seperating capabilities.
One option, but you got to make sure you have enough pump to push fuel through it...monitoring fuel pressure becomes crutial...
And some of the Racors are only rate for 90GPH, some pumps exceed this volume and that causes the micron ratings of the filter to change...we just had this discussion over at TDR.
I have considered adding a Frantz downstream of my current setup...that's be the only way to get any better filtration...
steved
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