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Fuel system homework

Old 11-09-11, 03:30 PM
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Fuel system homework

Hello all,
I am doing my research for upgrading my FC AutoX car's fuel system. I want to do it right and also not over kill the set up. Meaning, I don't need more then what is safe for my power requirements, while at the same time keeping it as light as possible and "simple".

Here is a quick background of what I am working with currently:
FC XP autoX only car.
~400hp (dyno'ed at mile high, now sea level)
720 primaries, 1000 secondaries
Upgraded fuel pump, bigger Turbo
Motec M4
Stock fuel lines, filter, tank.

Here is the list for the new system I am thinking about buying.
Jaz 5 gallon fuel cell with sump. -8 fitting, foam filled.
Bosch 044 external fuel pump
10 micron Aeromotive filter
Aeromotive FPR
Tons of bucks in fittings.

I have read thru a lot of the threads regarding swirl pots, and I just don't see the need for my application. My autoX runs are ~60 seconds x3 or 4. The tank is sumped and foam filled, and I can easily keep enough fuel in the tank to prevent slosh/starvation. The added weight and plumbing/cost seems prohibitive to the added bonus effect, especially if I can keep the pump fed from the cell.

Also I am thinking of using hard lines instead of braided steel for the feed and return lines. It looks like 3/8" = -06AN lines. Looking at Pegasus suggestion on hose sizes, "they suggest" -06AN up to 300hp. -08AN above 300hp. That seems like a huge generalization, but is there any truth to the suggestion.
If I were to use the -08AN eqivalant in hard line from the cell, to-08 SS line, to the the fittings at the fuel rail, is there any ill effect from going from a larger flowing hard tube, to my smaller -06 Fuel rail fittings?
Should I keep it simple and just use 3/8" for the feed and return lines??

Is both 10 micron and 100 micron filters over kill for my setup? I run the car on race fuel, it sees maybe 20 gallons a season. Is using only a 10 micron filter after the pump enough?

Questions, comments, concerns.....
Thanks, 25XP
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Old 11-09-11, 11:10 PM
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Tons of bucks for fittings is right! Since your doing this upgrade have you put any thoughts to using E85? I just finished putting my uber expensive fuel system together for E85, and If I'd known then what I know now, I may have been able to do it more simple, and less expensively. What "bigger turbo" are you using?

good luck.
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Old 11-10-11, 01:34 AM
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Dan! You're alive! Hope the car is coming together nicely! Sounds like it is.
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Old 11-10-11, 02:02 AM
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I have done SS lines in the past, so I know what I am getting into, and I am planning on spending about the same on fittings, as my cell, pump and PFR. I will shoot high on fitting costs, and be happy when it's lower then my arm and leg. LOL

Honestly, I haven't even thought about E85, nor do I know anything about it. I have to admit, there is something intoxicating about the smell of race fuel. ummm

My turbo setup is a Garrett TE-460-1, .70A/R 360 thrust system with a HKS TO4B manifold, Tial 38mm wastegate. The setup was designed by TEC engineering for quick spooling, and works well for autox.

Any thoughts on the fuel system thoughts??
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Old 11-10-11, 06:56 AM
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My car puts out similar HP numbers as yours (A-Spec GT3574, 18psi). I use an Aeromotive FPR, an internal Bosch 044, the OEM hard fuel lines and plumb with AN 06 hose and fittings. I think this is sufficient for race fuel (100 octane) at this power level.

Just asking, do the the Jazz fuel cells meet the safety specs for your sanctioning body?

Guy
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Old 11-10-11, 07:46 AM
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-6 lines flow enough fuel for your configuration.

I am running more power with aluminum summit fuel lines and fittings.
2 x obx 280lph pumps wyed into one -6 to a Aeromotive A1000-6 FPR
2x1200cc and 2x1600cc injectors were happy!

Your tank selection might be questionable. I suggest going with a bladder tank such as an ATL.
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Old 11-10-11, 12:41 PM
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Thanks for the info guys.

The rule book for solo events isn't like the SCCA's road racing rules when it comes to fuel cells and roll cages. Neither are actually required, and for a fuel cell/system located inside the cabin, it needs to have a bulkhead between the fuel and driver.
I plan on going with aluminum Jazz cell, and then make a secondary aluminum shroud or bulk head to cover it. This is what I have seen other prepared drivers do for thier fuel cells.

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Old 11-10-11, 05:26 PM
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My auto-x car has in tank '044 to -6an to swagelok fittings to stock lines to Swagelok to -6an and no problems (besides having to run with lots of gas in the tank.

When I had a Walbro 255lph HP and the stock fuel filter it did have a pressure drop problem between the stock lines/fuel filter, but the '044 has good output even at elevated pressures.

If you were using a lesser pump and/or wanted room to increase the power the -08an might be a good idea, but the '044 can handle the pressure drop of smaller -6anfittings.

Oh, I did have one problem which is I switched premix brands and gummed up the paper fuel filter that came with the aeromotive filter. Fuel pressure showed as fine, but the car was running very lean in the low injector duty cycle areas (idle/cruise). Cleaned it with gas to get me by and then switched to stainless filter. With a 5 gal fuel cell you have a lot less gas tank surface are to build/dissolve varnishes on which is great- just keep an eye out for foam degradation of course if you go that route.
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Old 11-12-11, 10:04 PM
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Originally Posted by Dan Unk View Post
...I just finished putting my uber expensive fuel system together for E85, and If I'd known then what I know now, I may have been able to do it more simple, and less expensively.
Can you explain? Sounds like you have some valuable lessons learned. Did you go with a separate outboard surge tank? or replace the stock filter with a Stainless mesh version?
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Old 11-16-11, 09:57 PM
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Originally Posted by cone_crushr View Post
Can you explain? Sounds like you have some valuable lessons learned. Did you go with a separate outboard surge tank? or replace the stock filter with a Stainless mesh version?
So Here is what I did for my E85 fuel system. I made an external surge tank located behind the rear driver wheel, right next to the fuel tank as to make some of the plumbing easier. I used 2 walbro 255lph external pumps in parallel, as my HP goals are modest(350hp) I didn't need the bosh 044's. I also used a Jegs racing stainless 75 micron filter before the pumps and an 8 micron Canton racing filter after the pumps. Bosch 1600cc injectors x 4, as I can't afford Injector Dynamics 2000cc injectors right now, and an Aeromotive A1000-6 FPR. I'm using a Bosch 040 intank lift pump, which is awesome, it simplified things alot as the bottom is open and covered with a stainless mesh, no pickup sock to worry about.

What i should have done was to install two Bosch 040 intank pumps. This would have saved me a ton of money as i would not have had to buy the 75micron filter, $200 worth of fittings, and a $220 custom surge tank. It would have the same flow as the twin walbro set up, less amperage draw, and saved me about $500, which i could really use right now. Don't get me wrong, i like my fuel system the way it is, because in the event that 350-400hp isn't enough i can keep everything the same and just change the Walbro's to Bosch 044's. So I may have inadvertantly done something smart, time will tell.
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Old 11-17-11, 11:11 PM
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First, thanks for sharing your experience, it sounds very typical of the decisions needed beyond the 300HP level. It's very easy to be shocked (and stung) by the expenses resulting from fuel system upgrades. Sounds like you're not convinced the external surge tank is worth it. While it's a huge chunk of change, the peace of mind you'll have when pulling high G turns is a big deal. Adding another in-tank pump won't help if your pickup gulps air. You would always be wondering how low to let the tank level get without a surge tank, and with E85, a quarter tank becomes empty pretty fast. Bottom line is you made some good decisions (including not springing for ID2000 injectors) and now have a bullet-proof fuel system. The other option is to do as 25XP suggests and just go with a fuel cell. That should make the cost of fittings seem minor in comparison.

One oddity is the dual Walbro pumps mounted in-line. That would be worth a picture since they are designed for in-tank use. How did you rig them?

To 25XP: BLUE TII is right, AN -08 lines seem like overkill at ~400 hp on race fuel. Prolly not worth the routing hassle, I'd stick with -06. That changes with E85 though. A small fuel cell is a good choice on a dedicated AutoX car, no swirl pot needed, just keep it full.
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Old 11-18-11, 03:44 AM
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Well I ordered the Jaz 5 gallon cell from Summit Racing. I feel confident that with the sump and foam, I should be able to keep from fuel starving the pump. Autox runs a so quick, and I can always top up if need be.
Has anyone had any negative results with the Jaz cells, or the foam deteriorating?
Also ordered the Aeromotive FPR and Bosch fuel pump.
Based on all the great feedback, I will stick with -6AN hard lines, both feed and return.

I did not order a fuel filter yet, as I wanted to get some feed back on what micron to use, and how many are truly needed. I run Redline 2 stroke premix at a 1:1 ratio with race fuel, most likely 100 octane here at sea level. In Colorado the octanes levels were lower on fuels.
What are some suggestions to filters sizes and if anyone has imput as to where they are best placed in the fuel system. I have seen some fitted directly to the pump and others seperate from th pump. Less fittings and plumbing is one of my goals...

Is a fuel dampener still needed if using a FPR? I saw one on a system that was for sale locally on CL and if I hadn't just ordered my stuff, I would have jumped on it. It made me wonder if the stock unit is retained on the FC or if I need one, or it's eliminated all together? Thoughts, suggestions...

I still have to order the fuel line, purchase a flarring tool and then bend over for the fittings. I hope to save a few bucks on using the hard lines and fittings for that, but I realize just how quickly AN fittings add up.

Over all, I hope to shed a few pounds of weight with this system over the stock tank, keep fuel slosh down while running less fuel, but also knowing just how much fuel I have in the tank!

Thanks again for alll the feedback and input.
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Old 11-18-11, 10:25 PM
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Originally Posted by cone_crushr View Post
One oddity is the dual Walbro pumps mounted in-line. That would be worth a picture since they are designed for in-tank use. How did you rig them?
More than happy to share! The walbro pumps are 255lph GSL392 pumps, they are external pumps and they are mounted in parallel, using some expensive fittings, it turned out rock solid. A picture is worth a thousand words, so here is a couple pics of my surge tank and pumps. The pumps aren't wired yet, should be by the weekend.
Attached Thumbnails Fuel system homework-boys-e85-015.jpg   Fuel system homework-boys-e85-014.jpg  
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Old 11-18-11, 11:16 PM
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Damn, you've got so many fittings there's barely room for hose.
If those are real Walbro pumps they should draw less current than other makes. Interesting surge tank design with the filter nested underneath. Thanks for the pics.
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Old 11-19-11, 02:07 AM
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Fuel cell came in today, wow Summit Racing was fast, and free shipping.
The cell looks very well made, especially for autox use. I was hoping the sump would fit into the FC's spare tire space, but it's just a bit too big. I will have to make it fit with brackets.

Not that you can't see the cell in Summits catalogue, but here it is again.

More pics as parts come in and get installed..
Attached Thumbnails Fuel system homework-img_1200.jpg   Fuel system homework-img_1201.jpg  
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Old 11-19-11, 11:23 AM
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Just in case you guys have to buy a bunch of fittings like me, this place is a few dollars cheaper than anywhere else per fitting. http://aeroquip.cc/

Thats a very nice looking fuel cell. I wanted to put a simple surge tank in the trunk area, but in order to track it (NASA Time Trial) I would have had to build a bulk head between the fuel system and the rest of the car, or build a sealed box to keep it in, and that just seemed like to much work for me. So under the car it went.
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Old 11-22-11, 10:22 PM
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Pulled the stock FC fuel tank, filler system, straps, hardware and pump.
Threw it on the ol bathroom scale and it weighed about 30 pounds, give or take.
Jaz fuel cell on same scale, weighed in at about 4 pounds.
I am still waiting on the Bosch pump and Aeromotive FPR, and I assume they will add a few pounds. Nice to shave some weight while being able to run less fuel.
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