Fuel Issues at the Track

[Rehagen Racing]

We had a brand new Boss 302 doing this very same thing. As mentioned above, it was the transfer tube across the tank. While the pump was getting enough fuel from the main pick-up, the transfer tube had a small crack in it and was not allowing the fuel to properly transfer sides in the tank.

The customer took the car back to the dealer and had the tube replaced under warranty.

 

[barbaro]

We had a brand new Boss 302 doing this very same thing. As mentioned above, it was the transfer tube across the tank. While the pump was getting enough fuel from the main pick-up, the transfer tube had a small crack in it and was not allowing the fuel to properly transfer sides in the tank.

The customer took the car back to the dealer and had the tube replaced under warranty.

Thank you. I will look into that.

 

[JesseW.]

my car was fuel starving in turns at autocross. the in-tank fuel filter on the pump was clogged. changed it and fuel issues went away.

 

[Vorshlag-Fair]

I know that Terry Fair had increasingly bad starvation problems as he added more tire and aero to his car. He needs a half a tank at least to get the car all the way around a track with no problems.

Yep, the faster we make the car (higher cornering forces, from mechanical + aero grip) the more fuel we have to run. Towards the end of 2013 season I wouldn't go on track with any less than 3/4 tank, or risk fuel starvation on high g left hand turns. When you are exiting a corner and using the throttle to keep weight on the rear tires... then you lose power.... not good!

Every single spin I had this year was due to fuel starvation issues and the stock tank. Almost every time I went out with too little fuel it was simply an oversight - just forgot to check the fuel, or my wife drove the car in a previous session and didn't top it off like she was supposed to. We used the heavy fuel load for ballast/balance anyway, so it was simply an oversight when it was allowed to get low enough.

Same corner as below (NOLA Turn 16), loaded up and driven correctly

In my experience it wasn't so bad on right hand corner exits, but moreso on left handers. This was a non issue on street tires and even with Hoosiers we could run with 1/4 tank in autocross conditions. The long, sustained corners on a racing circuit, especially after we added some aero, really is what gave us fits with fuel.

This wasn't from fuel starvation, just overdriving. The motor never cut out in this corner and I used throttle to keep the rear tires loaded

For 99% of the people reading this, run 1/2 tank and you should be fine.

 

[barbaro]

Solution?

 

[Department Of Boost]

Solution?

I have the same issue in LH corners. I'm running 3 pumps though so it moves fuel fast. Anything under 3/4 tank and the car will go soft mid corner. I have not "fixed" it yet.

I was thinking of adding a high volume/low pres pump in the PS saddle that pumps into the DS on a switch would help.......Because Having three pumps in the tank isn't quite enough, LOL

 

[c_reber]

I used to have starvation problems really bad in my evo x. Never had a prob in the stang until last event at buttonwillow. I usually try and keep 1/2 or more fuel in the car and haven't had a problem (have ran Willow a few times as well, with no issues, but once again, I try to keep the tank as full as possible).

I suppose you could add a surge tank with a second pump to help cure the issue?

 

[2008 V6]

I’ve been off this forum for a bit –
Running two + fuel pumps in series won’t help too much in a fuel starvation situation. You only have the second vane pump priming the first. If there is no gas by the fuel tank pickup, no fuel will flow.

Fuel surge tank – I’ve made them out of 5”sch 40 6061 pipe and 5” 16 gauge 304 stainless. Both materials I had around & didn’t have to purchase use what you want but think about collisions. 12” tall is 1 gallon of fuel mine were 9” tall – ¾ gallon. All worked flawlessly with almost completely empty fuel tanks.
One in a FD3 RX7 430 reliable RWHP 2805 LBS with me in it Street / Track car running 285 & 295 R compound 30 series slicks on track. Second in a 70 Ford Ranchero 585RWHP and third in a 66 Mustang 382RWHP all long gone.
I did not mount my latest surge tank in my 2008 mustang. Made it & driver lost interest in racing. Stile might do it but other projects. Would have been mounted in the front of the spare tire well. Section the 9” piece in half with a 5/8” hole in the center to help baffle the fuel. Easy to make and plumb just a time factor.

Fuel pump / tank feed to surge tank below center baffle.
Separate pump mounted lower than surge tank for self priming connected to engine feed line located in center btm of surge tank.
Return from engine to surge tank to upper chamber or lower of surge tank. Overflow top center of surge tank return to pick up side of fuel tank.

Drawings should be available on the net. Maybe with better ideas.

 

[2008 V6]

We had fuel starvation problems on track with our boat using 265 street tires at anything below 1/2 tank of gas. Currently only 193 RWHP. 3500 + or – Lbs. I can't imagine with more rubber and a higher fuel demand in a racing environment. I couldn't find anything wrong with our stock fuel tanks. Thought everyone ran a surge tank to alleviate the problem.

 

[2008 V6]

Well this thread got me interested again so I put our car on our lift this morning and the fuel rail is not continuous flow meaning it does not re-circulate back to the tank. My surge tank design will not work for this application. I will have to re-think it – Possibly plumb the overflow back into and down the filler neck opening or else where but I don’t like the material ford is using for their tanks now. I have something to think about & a couple of phone calls to make when I have more time. I don’t know how the computer reads & interprets the signal from the pump– not my forte. Have to ask some question. Sorry about that. Shoulda woulda WTF.

 

[Rehagen Racing]

On the Boss R race cars that we build and run in Grand-Am, we use a return style regulator at the rail. This keeps us from needing a surge tank. The Boss R uses a fuel cell though, so it's very easy to put a line going back into the cell. On a car with a stock fuel tank, you need to get a little more creative.

 

[SoundGuyDave]

So os the 302R using a constant-pressure pump or thy "typical" turbine impeller pump with a FPDM?

 

[2008 V6]

On the Boss R race cars that we build and run in Grand-Am, we use a return style regulator at the rail. This keeps us from needing a surge tank. The Boss R uses a fuel cell though, so it's very easy to put a line going back into the cell. On a car with a stock fuel tank, you need to get a little more creative.

Thank for posting. The more advice the better.
A return regulator at the rail will not stop fuel starvation. If the pick up in the tank is exposed to air, the vane pump will captivate with an air bubble until primed again either by the velocity of the fuel traveling though the line causing vacuum or gravity. The injectors will see no fuel because an air bubble is moving though the line.
Your fuel cell will have slosh control and probably a surge tank built into it (one of the many very good reasons to use a fuel cell)

With the surge tanks I have made even if the fuel tank sucks air it gets pushed out of the top of the surge tank and the gas which is heaver flows under pressure out the bottom. You not only have the feed from the fuel tank but the return from the engine being fed into the surge tank giving a pretty large band-aid to work with. This will even work with carburetors. Control the flow with regulators before & after the carbs. On higher HP applications the float bowls empty quickly. The first one I made was used for carbs. I came up with a better idea later but this is stile the best I have come up with for fuel injection.

 

[Rehagen Racing]

2008 - You are correct in regards to the surge tank. The regulator will account for minor fluctuations, but prolonged starvation will still end with the same results.

 

[2008 V6]

Thanks for the input Rehagen -Been occupied –
No other ideas?
I asked one person about modifying the fuel rail for continuous flow but didn’t get a defendant answer about how the computer reads the input from the pump. – Any savvy computer people out there?

 

[Roadracer350]

2008, do you have any pics of the surge tank?

 

[SoundGuyDave]

Thanks for the input Rehagen -Been occupied –
No other ideas?
I asked one person about modifying the fuel rail for continuous flow but didn’t get a defendant answer about how the computer reads the input from the pump. – Any savvy computer people out there?

Honestly, not an expert, but I *BELIEVE* that the computer uses the fuel rail pressure sensor to modify the pump duty cycle to achieve desired pressure at the injectors. If you're going to a return-style system, you'll need a specific tune to lock out the computer from trying to modify pressure or it will get a tad upset that it has no control...

I don't think that the starvation issue is up front, I honestly think it has to do with the saddlebag-shaped stock tank.

 

[Department Of Boost]

Honestly, not an expert, but I *BELIEVE* that the computer uses the fuel rail pressure sensor to modify the pump duty cycle to achieve desired pressure at the injectors. If you're going to a return-style system, you'll need a specific tune to lock out the computer from trying to modify pressure or it will get a tad upset that it has no control...

This^^^^^^^^

I don't think that the starvation issue is up front, I honestly think it has to do with the saddlebag-shaped stock tank.

And this^^^^^^^^^^^^^

 

[2008 V6]

As embarrassing as it is - I don't even know how to post a pic.
I will have to look though several boxes of sht to find it. I'll give it a shot this week end. 5” 304 tubing tacked – no fittings welded in yet. I wasn’t sure of the size final size fuel line I was going to run. I was planning on bushing it down to fit the current fuel line if it was nessessary. Been put away for almost a year - maybe longer. i would have liked to eventually up-grade to a 5.0 run off of a separate stand alone computer - To time consuming & costly to change everything to a 2011. I didn’t ever check what the fuel needs for a modded 5.0 would be. Now if I do it, I would strongly consider a turbo 3.7 but the car will always be a Brick / boat and if that altered - virtually unsellable in the future. Most of the material I have bought & have laying around is from Burn’s Stainless – grade C – you have to walk in the door. They are somewhat local - 30 - 40 min drive.

 

[2008 V6]

Thanks - Sound Guy & Gmitch