Kansasrx7

Wondering if anyone knew how low on fuel for this to happen on hard turning or accel. Only have 4gals in tank rite now from it being out and totally dry. Possibility? This is the guage at a stop with 4gals to let you see (new mazda sender also)

aa35199

iTrader: (1)

The sides of the fuel tank curve in at the bottom, so any sloshing or consumption of gas appears to be more drastic towards the end. Mine does the exact same thing so no worries, also the baffling on these cars is quite good, you could probably do an autoX with 1 gal. in the tank. Speaking of this issue I am reminded of a a 4th gen carmaro I used to own, the fuel tank was shaped like a V and it was the same story, but worse, the first 3/4ths of the tank would take you 300 miles and the gauge wouldn't budge in a turn, and the last quarter was good for only 30-40 miles, with the gauge falling exponentially faster as you got lower. What a pos setup! that was the only time I ever ran out of gas.

80's old school

iTrader: (7)

Depends on how hard you "slosh" the fuel!! Usually with 5 gallons on gas in my car, I have no issues.

Last race at California Speedway, I had to keep over 5 gallons in the car at all times. If not after the hard turns, 19, 20, and 21, the car would fuel starve.

Of course my car pulls 1.6 G peaks, so your average street car would not have such an exaggerated problem.

85TIIDEVIL

iTrader: (2)

I have a Holley Blue pump which is loud enough to easily hear it humming from inside when I'm driving... Anything below a 1/4 tank and I can start to hear the difference in tone for a moment when the pump is running dry under hard braking for sure... And my tank is sumped.

82FanTC

iTrader: (9)

a slosh cup with a return will help to avoid starvation down to almost a gallon of gas

Kentetsu

I can run autocrosses with well under 1 gallon of gas in the tank. In fact, I had to do this for a while due to a hole at the top of the tank (dumping fuel on hard corners and slaloms).

If you find yourself starving while you still have at least some fuel in the tank, I would suspect a rusted pickup tube (sucking air from holes above the fuel level).

I would also swap out the fuel filter, just in case. Maybe it can supply just enough fuel to keep you going, but a small gasp of air from the rusted tube and you suddenly run dry (because the fuel filter didn't hold enough reserve to get over that brief "gasp").




Best of luck

80's old school

iTrader: (7)

Running autocross it was not so bad. I could run less gas. When running at California speedway, they use about 2/3 of the D shaped oval that nascar uses and then you peel off into a road course. When I run for 1 minute and 20 seconds turning only one direction the whole time and on a 14 degree sloped bank at 120 MPH.... there lies the problem. 5 gallon minimum!

I wonder if I have a problem with my pickup? I need to pull the tank someday and check.

elwood

iTrader: (1)

I had a fuel slosh / starvation issue -- also at anything below 5 gallons. Your setup makes a big difference. The float bowl on carbureted cars acts as a nice reservoir to allow short interruptions of fuel pressure without the driver noticing. With FI, there isn't usually any reservoir, so lapses are felt immediately. Presumably that's why Mazda added the slosh cups to -SE fuel tanks.

The cups help, but with a turbo motor, I can't afford to go lean, so I added a swirl tank.

Kentetsu

Does this happen on leftt hand turns more then right?

Wondering if you actually have the common fuel slosh in the carb instead...

bad 83

iTrader: (3)

That is what we did in my friends 13B-RE powered first gen. He could then boost hard at any fuel level without problems. The only reason that I haven't went that route is I do not like the idea of fuel lines ran to the inside of the car to the surge tank.

80's old school

iTrader: (7)

Kentetsu, I used to have the fuel slosh in the carb problem. I cured this with RX-2 floats. This cured it 100%. Before I had the carb slosh problem real bad while autocrossing.

VITOMAN1977

i hear this is common in the FD, is that true?

elwood

iTrader: (1)

I don't like the idea of fuel lines inside my car either, which is why I put mine inside the tank --> https://www.rx7club.com/showthread.p...ight=swirl+pot

It's been a great setup, from every perspective, but I realize it requires a lot of fab work. For a setup that's easier to execute, I saw a very good one that was mounted vertically inboard of the left rear frame rai, just aft of the OEM fuel pump location. I think he fed the swirl pot with a Carter carbureted fuel pump, then used a typical FI boost pump.

If you're injected, boosted, or corner hard (pick any two), a swirl tank really is the cat's ***. I can run my tank down to the E mark now without any worries.