Fuel System Filters

[builder]

The fuel system pump and some of the fittings have arrived, but no choice has been made yet on the filters (3). The design calls for a pre-filter to a pump on each line from from each tank. The two lines go to a "Y" block, then up to the main filter, and then on to the fuel rails. (separate AN-12 balance pipe added)

Since this is an LS7 (like the LS2), it is a "returnless" fuel injection system. So, the regulator is T'd in after the main filter. The line runs up to the rails after passing the T for the regulator.

Staying with AN-6 all the way from the factory tanks to the rail, the pre-filters are really only to protect the pumps and 100 microns should be more than small enough. But, since pumps generally blow fuel better than they suck, questions come up about flow for a 564 HP engine at WOT.

Anyone got any suggestions on parts for filters? Or, is this just too many filters and I should drop the pre-filter idea...

Thanks!

[mkoch1]

I am running a aeromotive 100m filter (pn 12301) after my holley pump before the aeromotive pump. Then a 10m filter after the pump before the rails. Turbo cars tend to eat alot of gas and I have had no issues at WOT.

larger image

mark

[crafty]

Mark, when investigating surge tanks recently I ran accross an article about a blown engine that had resulted from running the return line from the fuel pressure regulator into the surge tank. Something to do with overheating the fuel by running it through the engine multiple times.

[GTR One]

I considered using a surge tank too, but reckoned that with foam tanks at both sides...that I'd always get some fuel. Haven't heard of anyone having a fuel surge problem with a GTR?

With my LS7 install, I'm planning to install only 1 bullet filter before the fuel pump - It's a fine grade filter to stop the dirt..but also quite large (to stop the associated pressure drop. I guess I'm planning on the assumption that no dirt can be introduced within the pummp. Additionally I'm going to give my fuel system a very good flush before connecting it to injector rails.

Liam

[crafty]

I was having fuel problems and it turned out that my filter kept getting dirty and it didnt take much crap to make it starve for fuel. I am not sure where the dirt is coming from but to get around it I bought a stainless steel water filter housing and converted it into a temporary surge tank, hooked up toyota low volume pump and am now drawing filtered fuel from the temporary surge tank.

[builder]

mkoch1 said:

I am running a aeromotive 100m filter (pn 12301) after my holley pump before the aeromotive pump. Then a 10m filter after the pump before the rails. Turbo cars tend to eat alot of gas and I have had no issues at WOT.

Mark, I keept a copy of that image when I first saw it...like three years ago. Nice setup.

I probably won't use a swirl pot. The design might be modified to draw from one and return to the other, but only if I can confirm that one source will flow enough through a non-pressurized -6 filter. That's my concern. If I have to go to a larger line from the tank, I guess that's always an option.

I sent this image off to some pump manufacturers requesting an 80% duty cycle. That's why I listed 700 HP. It's really only 564 HP, but you never know what the future holds... Procharger maybe?

[srreck]

crafty said:

Mark, when investigating surge tanks recently I ran accross an article about a blown engine that had resulted from running the return line from the fuel pressure regulator into the surge tank. Something to do with overheating the fuel by running it through the engine multiple times.

I use mine for road/track since 2002 with a surge tank fitted. No problems to report. For the very hot trackdays in Spain we install a in line fuel radiator to protect from underbonnet temps over 80ºC that we have recorded in summer.


Sorry to the moderators, I clicked the report button instead the quote button ....sorry.

[GTR One]

[quote=builder


[/quote]

With the return line to just one tank I'm assuming -12 balance pipe will be enough to keep the tanks balanced??...especially at idle speed when most of the fuel (under pressure) is returned by the regulator.

I've planned it a little safer by returning to both via another T piece..

[mkoch1]

crafty said:

Mark, when investigating surge tanks recently I ran accross an article about a blown engine that had resulted from running the return line from the fuel pressure regulator into the surge tank. Something to do with overheating the fuel by running it through the engine multiple times.

I was worried about heating the fuel also. Aeromotive warned me about that when I was setting everything up. I believe most of the heat comes from running it throght the pump over and over. No issues yet on the road or the drag strip.

GTR One said:

With the return line to just one tank I'm assuming -12 balance pipe will be enough to keep the tanks balanced??...especially at idle speed when most of the fuel (under pressure) is returned by the regulator.

I've planned it a little safer by returning to both via another T piece..

I think this subject has been discussed before. You really need to make sure you are pulling from and returning to the same tank or you may over fill one side.

mark

[crafty]

Ive got both tanks liked with a -12
One pump drawing from a tee'd line that also links both tanks
The swirl pot returning to one tank
The regulator returning to the other

[builder]

GTR One said:

With the return line to just one tank I'm assuming -12 balance pipe will be enough to keep the tanks balanced??...especially at idle speed when most of the fuel (under pressure) is returned by the regulator.

I've planned it a little safer by returning to both via another T piece..

Thanks, Liam. Might have to do that...especially with the two pumps flowing so much at 60 psi.

[builder]

mkoch1 said:

I think this subject has been discussed before. You really need to make sure you are pulling from and returning to the same tank or you may over fill one side.

Okay, I will split the return line to both tanks.

crafty said:

Ive got both tanks liked with a -12
One pump drawing from a tee'd line that also links both tanks
The swirl pot returning to one tank
The regulator returning to the other

Grant, what size is the line with the pump on it? And, if you have a pre-filter, what size and type?

I am having trouble finding a AN-6 filter to put ahead of the pumps...one that won't restrict the flow too much. May have to go larger than -6. Sent an email to an engineer at Walbro to learn about the pull-through capabilities of their pump.

[GTR One]

www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=ROAD&pcode=FSEBULLA01

I've used this bullet motorsport filter (45 microns with cleanable metal element or 8 with paper one). It's 50mm bore so doesn't restrict flow much. I bought -6JIC, but there are loads of fittings available.

[Graham-P]

builder said:

I am having trouble finding a AN-6 filter to put ahead of the pumps...one that won't restrict the flow too much. May have to go larger than -6. Sent an email to an engineer at Walbro to learn about the pull-through capabilities of their pump.

Summit do a -6 billet filter part # EAR-230206ERL $34.39
Description
Fuel Filter, Inline Mount, Blue, 85 Microns, -6 AN Male Inlet/Outlet, Each
These Earl's in-line fuel filters provide maximum protection for fuel systems. They're available in your choice of a screen filter or a sintered bronze element. Either unit can be easily disassembled for inspection and cleaning. The filter housings are available with size -6 AN, -8 AN, or hose barb ends (bronze element only) for use with Earl's high-performance fuel line and fittings. They have a fuel flow of 4 to 5 gpm, and come in a nice blue anodized finish.

[builder]

GTR One said:

I've used this bullet motorsport filter (45 microns with cleanable metal element or 8 with paper one). It's 50mm bore so doesn't restrict flow much. I bought -6JIC, but there are loads of fittings available.

Thanks, Liam. I am wondering if the Earl's will work (price and location). If so, we have a Summit Racing here in Reno. (lucky us...that's where all my beer money has been going) The description for the Earl's says it's for a carb system, but that might not make any difference as a pre-filter.

[crafty]

builder said:

Grant, what size is the line with the pump on it? And, if you have a pre-filter, what size and type?

I am having trouble finding a AN-6 filter to put ahead of the pumps...one that won't restrict the flow too much. May have to go larger than -6. Sent an email to an engineer at Walbro to learn about the pull-through capabilities of their pump.

I have a -12 link on the front two fittings. Note that I originally had the pumps on these fittings. I then discovered that the foam is up against these fittings inside the tank. When I went to empty the tank by cracking the fuel line, it only dripped out of these -12 fittings... I imagine this is because the foam is against the side of the tank at the fittings. The reason I mention this is that the fuel is not going to quickly move from one side to the other through the front tank link - even if its -12. I would try to remove some foam around the fitting if you can. With my engine already in that was too hard so I left it (for now). I will be removing the engine in a couple of months to paint it and will fix it then.

so... I have one -12 line linking the tanks. I have another -12 line that also links the tanks, but it has a tee off it. The T has a -12 to -8 reducer. The -8 line runs to a paper type filter (throw away cheapie) then to a toyota pump (temporary) then into the swirl pot.

From the swirl pot is a -8 line with an Earl's filter (Summit EAR-230208ERL)
.... -8 to the Walbro pump.... reducing to -6 on the pressure side of the pump and up to the rails.


Jeff's old engine ran exactly that system but minus the swirl pot and pre-pump for 40,000 miles before he put the TT in there.....


I must say that without the swirl pot/prepump/filter the tiniest bit of crap in the Earl's filter and the pump wont keep up.... Im not sure that a larger filter would fix that problem as the pump just doesnt like to suck (a sackable offence in my book. Filtering the fuel into a swirl pot will definitely fix that.... so will clean fuel and lines. Im not sure how the crap got in my system, but im gonna keep the swirl pot/prepump/filter on there until the pre-filters dont get dirty any more.... I may make it permanent.

[builder]

Graham-P said:

Summit do a -6 billet filter part # EAR-230206ERL $34.39

Yes, this could be the one... The question remains flow numbers without a pump. If it's true that one horsepower requires .5 pounds of fuel per hour, an 80% duty cycle on 560 HP would require this filter to free-flow about .5 GPM (per side). I have an email into the folks at Earl's to find out if this will work.

[builder]

crafty said:

builder said:

Grant, what size is the line with the pump on it? And, if you have a pre-filter, what size and type?

I am having trouble finding a AN-6 filter to put ahead of the pumps...one that won't restrict the flow too much. May have to go larger than -6. Sent an email to an engineer at Walbro to learn about the pull-through capabilities of their pump.

I have a -12 link on the front two fittings. Note that I originally had the pumps on these fittings. I then discovered that the foam is up against these fittings inside the tank. When I went to empty the tank by cracking the fuel line, it only dripped out of these -12 fittings... I imagine this is because the foam is against the side of the tank at the fittings. The reason I mention this is that the fuel is not going to quickly move from one side to the other through the front tank link - even if its -12. I would try to remove some foam around the fitting if you can. With my engine already in that was too hard so I left it (for now). I will be removing the engine in a couple of months to paint it and will fix it then.

so... I have one -12 line linking the tanks. I have another -12 line that also links the tanks, but it has a tee off it. The T has a -12 to -8 reducer. The -8 line runs to a paper type filter (throw away cheapie) then to a toyota pump (temporary) then into the swirl pot.

From the swirl pot is a -8 line with an Earl's filter (Summit EAR-230208ERL)
.... -8 to the Walbro pump.... reducing to -6 on the pressure side of the pump and up to the rails.


Jeff's old engine ran exactly that system but minus the swirl pot and pre-pump for 40,000 miles before he put the TT in there.....


I must say that without the swirl pot/prepump/filter the tiniest bit of crap in the Earl's filter and the pump wont keep up.... Im not sure that a larger filter would fix that problem as the pump just doesnt like to suck (a sackable offence in my book. Filtering the fuel into a swirl pot will definitely fix that.... so will clean fuel and lines. Im not sure how the crap got in my system, but im gonna keep the swirl pot/prepump/filter on there until the pre-filters dont get dirty any more.... I may make it permanent.

Geezzz Crafty, you have been over the coals with the fuel system. It sounds like you have it just about sorted, though. Thanks for the suggestions....

If Earl's comes back with a positive answer, I will try the setup in my diagram...plus Mark's suggestion to split the return to both tanks...and see how that works.

I can't think of what could be causing the crap in you lines. Is it possible it's coming from the fuel station? I often wonder what it must look like in my tank...like the bottom of the water heater in my house, I suspect...with all kinds of crap in the bottom waiting to be flushed out every year.

We'll see how the -12 line flows. I was planning on removing a couple of inches all around the openings.

[Pilot Pete]

If anyone is intrested
I've got a 100mesh -6 Mocal fuel filter
and a new Holly high pressue pump
I could sell

[builder]

Peterson Fluid Systems makes a series of -6 filters that will work for this application. It's about 2x7 inches including fittings and is available in 45, 60, and 100 microns. I will be using two of the 60s as pre-filters and one of the 45s as a post. 09-0616 (60m) and 09-0610 (45m) The only question remaining is size and fitment. Is there enough room for these filters and pumps? I think so, but have to measure it up.

Crafty, I have had some interesting conversations with the engineers at Earl's, "Earl's Indy", and Peterson Fluid Systems that actually design their products. Perhaps the reason you are having "crap" in you lines is not that your lines are full of it ( like some people ). It's probably just coming from the pump gas being served at your local station.

The engineers I spoke with wouldn't sell me the type of filters I was considering. The screen-type in-line filter (like the Earl's 230206 or 106) only has about a squre inch (coin-shape) of filtering. Yes they flow well, but only for as long as the screens stay clean. With this type of in-line filter, they said I would have to check it about once per week. Otherwise, I might starve the pumps...and engine! BANG! The preferred type has a filter that's the length of the housing with pleats (like an air filter).

Hey, and guess who sell Peterson stuff; Schwartz Performance.