12v92 dual racor filters

[oceanjake]

My boat is set up with dual racors, each with its own valve. I think it is supposed to be so you can switch to a clean filter while underway. The previous owner has been running them both open, basically dirtying both filters at the same time. Does the 12v92 draw so much fuel as to require two filters to flow enough fuel? Or can I run them one at a time and use the setup for redundancy? I prefer to run 10 micron racors by the way rather than 30. Infind it keeps the spin ona clean longer. Penny for your thoughts

[hoop1013]

The 8v92's (715 hp) in my 58'MY have one large Raccor each. The Cat 3412's (1400 hp) in the 60' Sportfish have 2 large Raccors each. The last boat I worked on as a Hatteras employee had Cat C32 Acert's (1800 hp) and had 3 large Raccors per engine........starting to see a trend ?? My guess is you probably draw enough fuel @wide open that 2 filters per engine are needed for sufficient flow.
😎

[oceanjake]

Thanks for the (bad) news lol. I guess I'm not surprised. I will need to look up the horsepower rating but I believe the flow is about 50gph per engine running hard.

[tonytrakovich]

I have 12-92s on my boat with the same set up. The racors are rated for 180 gph with 30 micron filters. I don't remember if I am running 10 mic or 30 mic filters. At wot, I don't think you will burn more than 70gph per engine. I routinely run just one racor. If I run into an issue with fuel, I simply switch to the other racor.

[Pascal]

I ve seen many boats where people run both filters. Doesn't make much sense as you loose the ability to switch on the fly if needed. I run them one at a time, replace one and switch over at every oil change.

Been doing this for years on 1400hp 3412Es and on 1650hp C32s. Never had an issue.

[Avenger]

Keep in mind, these engines flow more fuel than they burn. Check that spec vs. the rating of the Racor.

[racclarkson@gmail.com]

I ve seen many boats where people run both filters. Doesn't make much sense as you loose the ability to switch on the fly if needed. I run them one at a time, replace one and switch over at every oil change.

Been doing this for years on 1400hp 3412Es and on 1650hp C32s. Never had an issue.Ditto. Run one or the other or risk clogging both underway.

Couple of points. The 30, 10 and 2 micron Racor 1000 filters all have the same 180GPH flow rate--not sure I understand the how of that. Racor points out that the finer the micron rating the more often they will need to be changed. My 1271Ti's top out at about 90GPH (WOT) or about 50% the capacity of one Racor 1000 primary.

It seems counter-intuitive, but Racor recommends the 30 micron for fuel of poor quality. Most people seem to look at it the other way; i.e., poor fuel needs more filtration. Racor recommends using the lower micron filters for fuel of known good quality. Maybe this is Rancor's position because they also recommend and sell secondary filters.

A 30 micron filter (or primary filter) is used to filter raw fuel (or poor quality fuel) before it can be further filtered by finer medias such as a 10 or 2 micron. A 10 micron filter (or secondary and even final) is used to filter fuel which is known to be of good quality. A 2 micron filter (or final filter) is the finest filtration available and is the last filter used prior to engine ingestion. A simple rule to remember is the finer the filtration, the more frequent the filter change. (Carry extra filters onboard). http://www.powermotion.net/files/95191975.pdf

What is for sure is that running finer filtration means you are more likely to shutdown from a clogged filter if you're not paying attention (speaking from experience). Therefore, running with both units online simultaneously is not a good idea. Given the identical GPH rates, there seems to be no issue running more filtration as long as you follow Rancor's admonition to carry spares. Indeed, many on this forum run 10's and 2's all the time.

Finally, you should have restriction gauges on both motors and the generator's primaries to warn you of a filter about to shut you down. Hopefully you will, in the course of underway checks, note any restriction approaching the yellow zone and take action then. On the farm machinery and heavy equipment I've run over the years, the rule was simpler. You changed filters when you experienced a loss of power.

[jrbrein]

I have dual Racor filters set up for my 6-71 N's as described above. I too run with one at a time.

I have suction gauges on both port and starboard Racors which is just one more thing that I keep my eyes on when underway.

Jon

[racclarkson@gmail.com]

Keep in mind, these engines flow more fuel than they burn. Check that spec vs. the rating of the Racor.That's a great point.

I was in error on the GPH at WOT posting for my boat. That's 90 GPH for both. At 45 GPH per side, that's 25% of the filter's rated flow of 180 GPH. I also have not noted any rise in the restriction at WOT.

[krush]

Many of these filters also "swirl" the fuel to help remove larger contaminants. If you don't have the proper velocity (aka not enough GPM) they won't work as well as they should.

[ageless]

My understanding about Detroit longevity has been clean fuel, air, and normal operating temps and they'll be happy. I have dual inline racors to each, run 30 micron in both. I would like to think I would catch a drop in pressure prior to being in a dire situation, but if it does I keep 8 extra filters and 5g of diesel on board for priming

[davidwigler]

I have 12-92s on my boat with the same set up. The racors are rated for 180 gph with 30 micron filters. I don't remember if I am running 10 mic or 30 mic filters. At wot, I don't think you will burn more than 70gph per engine. I routinely run just one racor. If I run into an issue with fuel, I simply switch to the other racor.

Don’t forget the return fuel. If you are burning 70 GPH you might be pulling 180 GPH through the racors.

[tonytrakovich]

I did not think of return fuel, but I have no problem running on one racor.

[racclarkson@gmail.com]

I did not think of return fuel, but I have no problem running on one racor.Neither do I. Actually, I had no problem running two motors off ONE Racor.

When I ran my port motor out of fuel July of '16, I was unable to get it restarted because of trash sucked up in the line. I caught the starboard motor in time to shut it down before sucking up trash and dropped the hook. Swapping Racors and changing the secondary didn't get me going. Fortunately, I had a cross connect fuel line installed in lieu of a priming pump. I ran the rest of the day and the next at up to normal cruise (1800) with the starboard motor supplying fuel to both itself and the port. I saw a little rise in the vacuum, but still well in the white. I chose to stay on the one Racor rather than to risk it, the port side fuel supply still being down. I also experienced no rise in temps one might associate with reduced fuel cooling.

Bottom line:

1. In my application, there is no known justification or advantage to operating with both filters online simultaneously;

2. There is every justification and advantage in paying closer attention to fuel management, and

3. It's good to drive a tank.

[saltshaker]

Keep in mind, these engines flow more fuel than they burn. Check that spec vs. the rating of the Racor.
X2! You pass a lot more than you burn. I have the same engines and setup. You need to run both unless you only run at hull speed.

[Avenger]

Many of these filters also "swirl" the fuel to help remove larger contaminants. If you don't have the proper velocity (aka not enough GPM) they won't work as well as they should.

Also an excellent point. On our polisher set up we've been able to outrun the depressurizers on the smaller Dahl filters. Where they're supposed to drop the velocity of the fuel to let contaminants precipitate out you could watch the chunks swirl their way upward if the fuel flow was too fast.

There is an optimum flow range. I know Dahl used to list "recommended" vs maximum "for comparison purposes" which leads me to think that some manufacturers may be very optimistic about capability.

[racclarkson@gmail.com]

X2! You pass a lot more than you burn. I have the same engines and setup. You need to run both unless you only run at hull speed.Jack, I don't have the same setup as you. But I don't think we're that close to apples and oranges either. I burn about 28-30 GPH per motor at 18-19 knots running 1800RPM. I have calculated that I pump about 90-100 GPH, one engine, at that RPM. In this case, one filter is well able to supply fuel. Indeed, the vacuum gauge confirms this. And as I posted earlier, I successfully ran two motors at cruise fed through one filter. I mentioned there was a slight vacuum registering on the gauge. At the combined two engine gross fuel flow of 180-200 GPH through one 180 GPH filter, this seems borne out by the reading and the fact that it indeed ran for nearly two days. Again, not the identical setup. All I can say is I always run one Racor per side and don't have supply or vacuum issues at speed. And running either one or two Racors, the fuel ends up passing through a single secondary filter. Thoughts?

[SKYCHENEY]

Vac gauges will tell you if you are pulling enough fuel through. You don't need to look at specs, just look at the gauges. They tell all.

I run 2 micron filters in mine.

[MVCaprice]

On our 12v71s I have ran with one filter and both for extended periods. I like running both filters as I think it does a better job of cleaning the contaminants out of the tank. I also run 30 micron filters. At 12$ a piece they are not expensive enough to worry about cost. I personally would rather have clean fuel. I just stock about 12 or so extra filters on the boat and change them all about twice a year.

[MVCaprice]

I ve seen many boats where people run both filters. Doesn't make much sense as you loose the ability to switch on the fly if needed. I run them one at a time, replace one and switch over at every oil change.

Been doing this for years on 1400hp 3412Es and on 1650hp C32s. Never had an issue.

I see redundancy in running one engine off the forward tank and the other engine off the stern. If you have enough crap in one tank to clog one filter up and kill the engine it seems likely that you probably are going to have bigger issues that you need to address with that tank and you are going to keep throwing filters at it. You might be able to keep it running, but if its that bad would you really want to? I would be looking at the on engine filter at that point and would be concerned about water contamination.

[captddis]

I NEVER use 30 Mics!! It allows the fuel to plug the secondary filter up.

Run both racors and use 10 or even 2 mic.

[MVCaprice]

I NEVER use 30 Mics!! It allows the fuel to plug the secondary filter up.

Run both racors and use 20 or even 2 mic.

I use them because I was advised to by flowscan for the flowmeters. I agree that they are not ideal.

[Boatsb]

Flowscan needs 10 or larger.

[SEVEN]

Jack, I don't have the same setup as you. But I don't think we're that close to apples and oranges either. I burn about 28-30 GPH per motor at 18-19 knots running 1800RPM. I have calculated that I pump about 90-100 GPH, one engine, at that RPM. In this case, one filter is well able to supply fuel. Indeed, the vacuum gauge confirms this. And as I posted earlier, I successfully ran two motors at cruise fed through one filter. I mentioned there was a slight vacuum registering on the gauge. At the combined two engine gross fuel flow of 180-200 GPH through one 180 GPH filter, this seems borne out by the reading and the fact that it indeed ran for nearly two days. Again, not the identical setup. All I can say is I always run one Racor per side and don't have supply or vacuum issues at speed. And running either one or two Racors, the fuel ends up passing through a single secondary filter. Thoughts?

Robert do you prefer a 10 or a 2 as. Secondary?

[saltshaker]

Jack, I don't have the same setup as you. But I don't think we're that close to apples and oranges either. I burn about 28-30 GPH per motor at 18-19 knots running 1800RPM. I have calculated that I pump about 90-100 GPH, one engine, at that RPM. In this case, one filter is well able to supply fuel. Indeed, the vacuum gauge confirms this. And as I posted earlier, I successfully ran two motors at cruise fed through one filter. I mentioned there was a slight vacuum registering on the gauge. At the combined two engine gross fuel flow of 180-200 GPH through one 180 GPH filter, this seems borne out by the reading and the fact that it indeed ran for nearly two days. Again, not the identical setup. All I can say is I always run one Racor per side and don't have supply or vacuum issues at speed. And running either one or two Racors, the fuel ends up passing through a single secondary filter. Thoughts?i believe the 92 series return a lot more fuel than the 71's but not certain. I think my engines pass as much as 3x the burn rate. I burn around 50gph per engine at 1950rpm cruise, so I could be pumping as much as 150. My engines are rated at 1100Hp considerably more than your 12V71s. I could see running one for your setup but the original post was for a pair of 12V92s

[racclarkson@gmail.com]

Robert do you prefer a 10 or a 2 as. Secondary?Rusty, I run 30 primary and 10 secondary. I've never plugged a secondary.Jack, Still think one Racor would handle a 1292. Why not see what the vacuum gauge says.