Swirl pot suggestions?
- Thread starter Zoey
- Start date
I am surely no expert and hopefully someone with more knowledge can chime in. The only change that should be made to the drawing is that the pre filter comes before the LP pump. Remember, these LS crate engines have a return-less fuel system (at least mine does)which is why it's plumbed this way.
Not usually a problem, but make sure the low pressure pump flows more than the high pressure pump.
I really hate to resurrect this old post, but I need some help understanding.
I see above that it is generally recommended to use the Bosch 044 (after the surge tank), and I know from the specs that it flows about 79-80 gph max or 299-300 lph.
Thanks to this post and Wayne's diagram (shared elsewhere), I am about90% clear now.
I see above that it is generally recommended to use a Walbro low-pressure pump (before the surge tank), but I am struggling to figure out which inline model. I only see 255-lph inline models and none of them indicate low-pressure, high-volume. To add to my confusion, I see the above quote to make sure the low-pressure pump flows more than the high pressure pump (i.e. >299-300 lph)...won't this outflow whatever fuel is supposed to be inside the surge tank? :shy:
Thanks for any clarification in advance.
v/r,
Harold
Molleur: Yes. I noticed that (what an awesome schematic, other than the minor labeling issue mentioned above BTW). I think I would prefer a surge tank similar to the one depicted in Wayne's schmatic to the one available from CXRacing because the CXRacing version has different -AN fittings on the top three ports (-8AN on very top and -6AN fittings on the two top-side ports)...Wayne's diagram makes better sense intuitively. No easy button, I guess. Thanks.
v/r,
Harold
I might add one thing not mentioned(least I didn't look that far back) and that is the regulator. The setup is O K if your running a carb(s) setup. If you have Fuel Injection the regulator needs to be "after" the injectors, and then returned to the swirl pot. The injectors are a lot higher(30- 40 lbs.) than carbs(4-8). Of course this if you don't have the "returnless" injectors.
Think of this way. If you have the injectors for each cylinder it is like a water hose with a lot of takeoffs. The one one the end will have less pressure feeding it and may starve from low pressure supply. Not so much from cruising but with WOT. I hope I am making this clear.
Bill
Think of this way. If you have the injectors for each cylinder it is like a water hose with a lot of takeoffs. The one one the end will have less pressure feeding it and may starve from low pressure supply. Not so much from cruising but with WOT. I hope I am making this clear.
Bill
The LS engines are mostly returnless (all of them have been so since 1999, AFAIK), so the regulator has to be before the rails.
I couldn't find any commercially available swirl pots with the right number, size and placement of fittings when I was looking- so I have one of the original "Wayne" versions. I think these are a great solution, can be easily duplicated, are known to work well, and are inexpensive.
Dave Lindemann
Lifetime Supporter
This looks to be an interesting option: 650hp Single Aeromotive 340R FST: Radium Store . They have options for a variety of internal fuel pumps, .40-gal capacity, aluminum construction. These are "Lotus" related - I'm no expert on fuel systems - any potential problems with these?
Dave L
Dave L
Here are several other options I have found.
Fuel Swirl Pots & Collectors | Fuel System | Motorsport | Home | Demon Tweeks
Fuel Swirl Pots & Collectors | Fuel System | Motorsport | Home | Demon Tweeks
I can see potentail problems with air being introduced into the surge tank from a starved primary pump and then being sucked up by the pump in the surge tank, then passed along to your injectors. I don't really see the point in something with such a small capacity like this on cars like ours. On a Lotus clone, where packaging is far more constrained, this may have its place.
To clarify, this is not a swirl pot, only an external surge tank. A swirl pot, due to its plumbing design, will help eliminate the chance of any air getting picked up by the secondary pump while a surge tank does not necessarily do that.
Dave,
You have to remember that at the moment that air is introduced to the surge tank or swirl tank, that a lot of things are going on. You have that supply of fuel to the HP which is pumping to the injectors. All that the injectors don't use is dumped back into the surge tank and back to the HP again and so on till the injectors use all that is available. Then and only then will air get to the HP. So unless you are coming down a mountain it will be a while til you run out of fuel in the surge tank. Some have added pickups in the front of their tanks to keep even that from happening. If you have built your pickup with baffles, similar to the ones seen on the Demon Tweaks catalog posted above, that will help prevent the possibility of starvation. That is the way I built my tanks.
The flapper is on a hinge that allows fuel in but not out. Not perfect but it works.
Bill
You have to remember that at the moment that air is introduced to the surge tank or swirl tank, that a lot of things are going on. You have that supply of fuel to the HP which is pumping to the injectors. All that the injectors don't use is dumped back into the surge tank and back to the HP again and so on till the injectors use all that is available. Then and only then will air get to the HP. So unless you are coming down a mountain it will be a while til you run out of fuel in the surge tank. Some have added pickups in the front of their tanks to keep even that from happening. If you have built your pickup with baffles, similar to the ones seen on the Demon Tweaks catalog posted above, that will help prevent the possibility of starvation. That is the way I built my tanks.
The flapper is on a hinge that allows fuel in but not out. Not perfect but it works.
Bill
Wayne,
Your diagram has clarified what was once as muddy as the Mississippi for me. One question I have is this: I may use an 8-stack and if I do it's a return system as Bill alluded to above. I don't think that it can be converted to the returnless system you've outlined above can it?
If not, the line from the swirl pot would go directly into the injector and the regulator would be after the injectors. Would the line from the regulator dump back into the swirl pot?
Steve
Your diagram has clarified what was once as muddy as the Mississippi for me. One question I have is this: I may use an 8-stack and if I do it's a return system as Bill alluded to above. I don't think that it can be converted to the returnless system you've outlined above can it?
If not, the line from the swirl pot would go directly into the injector and the regulator would be after the injectors. Would the line from the regulator dump back into the swirl pot?
Steve
