Fuel Capacity

[escapepilot]

1. What is the total fuel capacity of the metal tank?
2. How much of that is unusable (engine will quit before totally empty)?

I was cutting it close yesterday on the way back from a show in Carolina Beach, NC. Usually, I once the gauge shows half a tank, I plan on stopping, but I was probably less than 30 miles from home when it got to that point. Rolling into my home town, it was indicating about 1/8 tank (no low fuel light yet) but I could feel it surge a bit during left hand turns on the highway. Turning left into the gas station, it quit and I coasted to the pump. Took 7.2 to fill. Still no low fuel light. I don't expect it to be an accurate gauge, but I thought the tank would hold 9 gallons so 1.8 unusable surprised me. That is almost 1/4 tank. (I was able to

 

[95Blitz]

Is the tank baffled (I didn't look before installing the pump assembly)? I would hope it is. But with 1.8 still left it sounds like it isn't.

 

[Robinjo]

I once got to 9.1 gallons used (that's what I pumped in) and it was driving but under full throttle the engine was getting starved. That's the most I've ever put into Drago. Mine shows empty on the gauge at 8 gallons used, but I think I bent it a little during install.

My fuel light does come on with about 8 gallons used just basing it off what I put in when it warns me. Oh, and not a light but a message on the gauge cluster about being 'hungray for 93 octane'.

 

[jirwin]

Is the tank baffled (I didn't look before installing the pump assembly)? I would hope it is. But with 1.8 still left it sounds like it isn't.

Yes, slightly. Noticed when I had it apart the other day. Theres a small wall maybe an inch and a half tall in the middle that tries to keep the fuel on the drivers side (as far as I can tell)

 

[duthehustle93]

Is the tank baffled (I didn't look before installing the pump assembly)? I would hope it is. But with 1.8 still left it sounds like it isn't.

+1 with jirwin. #05 (SS/TC) is an aluminum tank with a baffle, but it's very short. It should work fine for street use but would probably starve the pump under track use.

I can't confirm this, but a buddy of mine has a newer chassis (I believe he's in the late four-hundreds) that's SS/SC and I believe he said that he has a plastic tank that doesn't have a baffle... if there's no baffle on a tank this wide I could definitely see you having issues scavenging to the bottom. Sloshing or lack of a baffle will cause inaccuracy on the gauge as well as early starvation. It's not apples to apples, but on our endurance race cars, we were getting fuel cut at about 1/4 tank on the miata and 1/3-1/2 tank on the BMW. Baffling and a new fuel pump sock helped us scavenge to the last 1-2 gallons. I would check if you have baffling, and if the SS/SC models have a sock, I'd also replace it. Sometimes a pinhole can cause scavenging issues.

FWIW, here's an old thread regarding tank capacity: https://dfkitcar.com/forum/index.php?threads/fuel-tank-size.349/ ... I think there's been a lot of iterations to the fuel tank, mine is different from any of the other ones I've seen but I can't imagine volume changed by more than 10% through the iterations.

 

[Desert Sasqwatch]

Depending upon how much bend (or not) is applied to the fuel pump float arm will determine where your fuel gage indication aligns with the actual fuel level. Some have bent it to be more 'accurate' for full, others for empty - some left it as stock. Asking what others are reading on their gage versus the amount of fuel in the tank will be highly variable. But the concensus on the forum is the tank holds between 9 and 10 gallons and has between 8 and 9 gallons usable- without long duration turning.

Yes, the metal tank has a baffle, but because of the shape (long, narrow and tall) fuel will travel from one end to the other during long duration turns. A baffle is only used to reduce sloshing, it does not keep fuel in a specific area of a tank. To do that a sump is needed to hold fuel at the fuel pump or fuel tank foam to further reduce fuel travel or fuel pump 'sock' - like Holley offers.

 

[jirwin]

To add to what DS said, I noticed that at least on the non turbo pumps there is a tiny "surge tank" built right in. Pretty neat design. Basically theres a bucket with a hole in the bottom where the pump sucks fuel in. The bucket is filled by the return line and feeds the fuel pump as well. Pretty nifty bit of engineering.