is anyone using anti slosh foam or anything similar in there standard fuel tanks? i use roughly 20l of fuel in a race and cant help thinking that is a lot of weight sloshing around in the big unbaffled tank. i am also worried about fuel starvation at the end of the race. i know the correct way to do it is to run a swirl pot but anyone got any experience on this?

 

Have you experienced fuel starvation? The stock sock in the stock configuration has proved very anti-starve friendly. I wouldn't mess with a good thing.

 

not as yet but with the ongoing quest for less weight the fuel levels at the end of a race could be very low. suppose we could just run a little extra fuel but that still wont help the sloshing effect upsetting the handling.

 

We used it in my brother's car (240SX, which did have a pretty severe starvation issue). It worked pretty well, but does break down over time. If you use it, plan on either draining the tank after every event, or replacing the foam every 1-2 years.

 

I've hit fuel starve once in the local track's rental miata in T2, buy the time limped it around the track (2.9 mi) and putted into the paddock, it died. I promptly put 11 gals of fuel into it.

IMO fuel starve is not an issue

 

From what I've read, Miatas will only go through fuel starvation if you put the sock on the pump wrong.

 

^ what he said - I know this first hand. Little less than half a tank and I'd get starvation in hard cornering. Before I installed the OEM sock, I cut it open and inserted a nylon 'pick-up' tube inside of the sock, which gives maybe 2" more depth into the tank?

https://www.miataturbo.net/attachmen...1&d=1318725774

 

mr2daj, you said you're using 20L, which equates to roughly 5 gallons. If you're looking into weight + improved slosh control you could consider a 6-gallon fuel cell. It would be smaller than the stock tank and would have the foam in it already. It would also definitely be a bunch more money than just throwing the foam in a stock tank though.

 

yea that was always an option. maybe next winter. if its not going to be a problem then i wont do anything about it. if it aint broke dont fix it.

 

Never had an issue with fuel starve, mine just runs out, no sputtering, no coughing only no mo' gas.

 

dude, I run on track with less than 2 gallons in the tank all the time. Have yet to have any starvation issues, although I possibly maybe MIGHT have once when I spun the car out with less than 3 gallons (and I am talking about a 540/720 spin here, not a 180 or something of the sort).

Lesson? Don't spin the car out under 3 gallons and she won't starve.

 

Miatas do not fuel starve unless they are actually 100% out of fuel. If yours fuel starves, it is broken and you need to fix it.

If our Rental (Walbro 190LPH, factory fuel hangar, factory fuel sock) stumbles from fuel starve on track, you have approximately 5 miles at highway cruise speeds to get it to a fuel station before it will not idle on level ground.

 

Hate to be nit picky, but that's 98.4% out of fuel, not 100%. Just saying.

Anyways, he switched his argument to saying it'll help with handling from the sloshing. Another "if it ain't broke don't fix it" scenario. There are hundreds of other things you can do to make your car handle better. Like finding a single pound to take out somewhere. Or emptying your bladder before a run.

 

1 gallon ~ 6 lbs.

if you run 5 gallons per race, you are not sloshing much weight. Compare that to say your spring rates (400+?), you would need quite a bit of weight to have a significant effect.

 

fair enough. thanks for the advice! money best spent elsewhere. never had any problems before. it was just a thought for over the winter.

 

Fwiw, I've used plenty of the foam in fuel cells in race cars (grand-am GS class mustangs) and it doesn't do ton in the way of slowing down the fuel moving while cornering anyway. There is also some combinations of fuels and the foam that can dissolve the foam and it makes it pas tthe filters but will clog injectors. This is not documented anywhere that I'm aware of, with anyone's fuel or the fuel cell foam, but the team I was crewing for, as well as a number of others were plagued by it a few years back until the fuel spec was changed. My best recollection was that it was the common yellow fuel cell foam, and fuels with ethanol were where the bulk of the issues showed up.

 

Fuels with ethanol like E85 or normal pump-gas stuff with E10?

 

I run a surge tank and external fuel pump in my system.

 

Closer to E10 in the case I was involved in. We were running in Grand-Am Cup (now Continental Sports Car Challenge) and the spec fuel was pretty much the 100 octane pump gas that Sunoco offers. When the issue came up, Sunoco and Grand-Am eventually switched the spec fuel to 260GTX, which I was told was the same blend as the 100 octane stuff, but without ethanol. The resulting octane was 98. After the switch, we never had an issue again.

We really had a devil of a time figuring out what was happening at first though. Clean fuel filters every time, even down to some pretty low micron stuff, with multiple filters in series, and yet the screens in the injectors would all get gummed up where the dissolved plastic from the foam would come out of solution.

 

Why? What issue did you solve by switching to a surge tank?