rmackintosh

How are you plumbing the fuel systems in your C6 race cars???

I have twin tanks, the crossover tube and some small tubing between the tanks...vents to gas cap area. On the passenger side there is a bigger hose that I assume went to the charcoal canister...which is gone now.

I think I read the Corvette has a single line to the fuel rails and no return line to the tank or regulator.

Is that how you plumbed your race car?

Did you just buy a good Z06 pump and that is it?

Did you just plug the charcoal canister hose?

My LS7, in the Camaro had a feed line to the rails, then a pressure regulator at the back and then a return line to the tank. I have all of that stuff if I need to plumb it back that way.

Any photos?????

travisnd

I didn't do mine from scratch as I built a C5Z into my race car, but I ditched the charcoal canister because it was in the way of where the main hoop of my cage needed to be. After conferring with DrivinhardZ06 and Sperkins I just left the hose open and zip-tied it secure. Then I had my tuner delete any EVAP codes and took the EVAP stuff off of the engine. I still have the EVAP line running down the firewall and back to the tank area, but it's not hooked up to anything on either end. I use the stock pump and the stock fuel lines and injectors. The C5 ditched the return system for the '99 model and went returnless. The '97 and '98 had a return setup.

I'm sure you could hook up a return system if you needed to run one, but I'm not familiar with the pros/cons of each.

0Louis @ LG Motorsports

Take the stock stuff and set it aside. The stock jet pump system will not drain both tanks in compeition use, WOT for 45 minutes.

You need 3-4 pumps, 2 scavenge pumps, one for each tank, feeding into a surge tank. Main high pressure pump pulls from the surge tank, and your reserve pump can pull off the surge tank as well.

Engine return feeds surge tank as well. When surge is full, it overflows back to the main tank.

Louis

travisnd

Interesting... most everyone who races at the amateur level runs a stock based fuel system and I've never heard of any issues with the OEM transfer pump not working in race conditions. It's a pretty simple system by which a vacuum is created by the flow of the fluid in the main line by the pressure pump which pulls fuel from the passenger side tank to the driver's side.

Jason

Our races aren't long enough to run the tanks that low enough for it to be an issue I'd imagine.


If I had more than 5min the week before a race to work on the car, I'd reverse the tank-to-tank flow.

Zip Corvettes

Most everyone I know with C5 race cars is running ATL tanks in the rear and have gotten rid of the stock tanks. Randy you are asking my same question. I have been working on mine since I decided not to sell it to ya, now it looks like we are almost in about the same place. I have all my stuff installed for running the stock setup with a ZO6 pump in mine, but I am not 100% for sure that is how it would stay. I was thinking of running two main pumps, one in each tank and then running return lines back to the tanks. I would bring the two line into a Y and a single -6 into my main fuel rail with fittings welded to the end along with the returns. I would also have to add a fuel reg to make my tank setup work like that. That may be a winter project, I think for now I am going to run stock config just to get the car out there on the track sooner rather than later. Louis is right though it is to be done right. I am still considering the ATL tanks for the Corvette.
Justin

0Louis @ LG Motorsports

With Randy's setup, he may run into an issue. Being able to start from scratch on a fuel system is important in the future of his car.

While Club racers may be able to use the stock system, and may be forced to run the stock system ( due to rules) Randys unique opportunity can allow him to do what ever is best.

We run stock tanks dry, with 2-3 gallons left in the passenger side cell. That can be the difference between winning a race, and not. Build your fuel system however you want, but Take it from our experience, Dont make that mistake.

rmackintosh

If I did this configuration, what pumps would you use in the tanks and what pump would you use from the surge tank?

Is there a problem running the in tank pumps if one tank runs dry? For example...you mention running it until there is only 2-3 gallons left in the passenger tank. What happens to the pump in the main tank that has been running dry for a period of time?

Thanks a lot!

rmackintosh

...oh...and how big should the surge tank be?

Thanks.

0Bobby @ LG Motorsports

Fuelsafe and ATL both have pumps that are meant to be run dry for extended periods of time. They also are designed to be low amp, low pressure, so you dont have a lot of draw on the electrical system.

Running most pumps dry for that lap or two, isnt bad.

Surge tank should be large enough for 1 full lap, at your longest/most fuel consumption heavy track that youll run at. For us, in the GT2 car it was Le Mans ( 2 gallons, 4mpg, 1 lap) Grand am car was 1.25 gallons ( Daytona, 2 laps, 4.75 mpg)

I would do 1.5 gallons min, run a bosch 044 race pump as the main, high pressure pump, and call ATL/Fuelsafe for their recommendation on scavenge pumps.

Zip Corvettes

I think I might go that route to, mine and Randy's build is almost identical. Bobby where are you mounting the surge tank?

trackboss

LG described the best way. Two high pressure pumps are only used if you choose to have a backup which is a good idea. If you decide that then run a check valve on each pump on the output side and feed into a "Y". From there continue forward to a rail (or near rail) mounted regulator. Wire them using a single switch that is double pole double throw (I think that is the correct term). "up" position energizes relay that powers main pump and "down" position energizes relay for backup pump. "middle" position is "off". It would probably be best to run a separate switch/relay for the lift pumps(both 87 poles used;one for each lift pump). The return line should come from the regulator into the surge tank.

0Louis @ LG Motorsports

Surge tank typically goes between the engine and the fuel cells. Usually, we mount them between the frame rail, and the transmission, offset of the driver (weight advantage)

Ill see if I can dig up some pics. The ALMS car and the Grand Am car both were required to run the reserve cell/surge tank, inside the bladder. What a complicated mess. Any maintenance, and the cells had to be opened, or even removed from the car.

Louis

davidfarmer

I agree the C5 siphon system could not keep up, and you'd end up with a lot of extra fuel in the WRONG tank. However, in our C6Z06, I find it can run down to nearly completely dry with no fuel issues.

That being said, unless you need to use every single drop of fuel, I'd simply buy and decent quality low pressure pump to move fuel from the drivers' side to the passenger side, then use a high quality, high pressure in-line pump (just a Walbro etc) to feed the engine. You can run a regulator at the rail (requiring a return line) or at the back.

If you only need 8 gallons of fuel, for sprint races, I'd cap the drivers' tank and run the single passenger tank.

0Bobby @ LG Motorsports

I agree that you can run them down nearly dry, however, the drivers tank always full, you can be at a 1/2 tank, and never see an issue.

Where you see the issue is at a full tank, running it dry. Under racing conditions with a race car that makes more than OEM power, itll suck it dry before it can transfer all of it over.