Have any of you experienced power/fuel cut out when you were racing on the track with about 1/4 tank of fuel left?

I always have this problem as soon as the needle pointed to 1/4 tank of fuel. However, the cut out didnt happen in the corners. It happened only on a straight after the corner and only that location on every laps. Buttonwillow after turn 2, Thunderhill after turn 15 , Autoclub speedway after turn 11,e.t.c.

I filled up the tank and it only took 12 gallons of fuel.

Is this normal to our Z? (btw, 04 non-rev) or anyone experienced that and got that fixed? This is become so annoying when the car became lighter for lap time and it started to cut out!!

Thanks in advance!

 

Yup - it's a known issue. The cornering load moves the fuel to the driver's side while the pickup and pump is on the passenger side. You end up pumping air for a couple seconds and once that bubble makes it to the engine it takes a little cat nap.

We took the tank apart and made sure that the pickup line that runs from the pump over to the drivers side stays put and is low as it can get. Short of that, you'd want to put a fuel cell in the car. Running a heavier fuel load is also an option but that comes with a weight disadvantage. If all else fails, drive slower and the problem goes away completely.

 

Go slower, I like that

I haven't had it myself that I have noticed, but I am on stock suspension and street tires still. I have heard of it from a few people, especially those on slicks.

BK: Did that seem to resolve things? Did you see any other modifcations that could be done to tank to fix it?

 

Rob: For the most part, that did resolve things, but it took a few tries to get it right. In T3 trim (3400 pounds / 245 tires) it's a non-issue; the car just cant generate the cornering loads necessary to cause a problem. In T2 trim (3168 pounds / 285 tires) it's pretty common but we can now run the car pretty close to empty - probably within 3-4 gallons of dry.

FYI we've seen the same issues in the 370Z at 1/2 tank of fuel but haven't spent a lot of time trying to correct it yet since we're still sorting that car. I suspect the solution will be the same.

Brian

 

If you can make it to 1/2 tank in a 370z you are very lucky indeed. I know people who can't go a full session from full tank without starving the thing of fuel.

 

That sounds right. It happened everytime after a hard right turn. I definitely will try to open up the left tank and check the tube. Thanks for the advise.

P.S. Seems like another major problem with the Z34 beside overheating and sync shift failure. That's sad.

 

I really want to install another pump on the drivers side, link the fuel lines together and completely forget the fuel starve issue.

 

What about closing off the passage between the two sides of the fuel tank? It might be hard due to the corrosive nature of gasoline on adhesive and materials, but would allow you to run 10 gallons of gas and maintain the OEM simplicity.

 

CJ Motorsports is getting ready to release a 370z fuel system to combat that exact problem. easy install with no chance of fuel starve

 

My buddy has this same issue, its brutal.

I can drive on fumes in my G35; its scary lol

 

I heard the 370Z's are much worse too.

I've only had it happen to me at Road America. I had just a hair under 1/2 tank sitting in grid and within two laps I was hitting fuel cut. Huge track with a lot of straights. I burned more fuel there than any other track by far. I didn't notice it until the 2nd day because it was a fun day and I normally have to run over 1/2 tank to make weight so it wasn't too bad of an issue, but it scared the hell out of me when it happened. I thought something broke. I realized what it was after the 2nd time it happened because it happened at the exact same spot on track. The kink at Road America is sickly fast. Looked back at my GPS data; when there was no traffic I was coming through there at 112-113. As soon as I finished tracking out I hit fuel cut. Here is a video from there. You can see the kink that I am talking about. There is no fuel cut in this video though.

http://www.youtube.com/watch?v=12lniVxdm2U

Are your speeds about the same in the corners you have issues with?

 

Really severe. As slow as I am I was getting fuel cut at Mid-Ohio on the keyhole and into thunder valley with a bit better than 1/2 tank and street tires. Some folks report it within one or two laps on slicks at certain tracks.

The worst I had was at Grattan with an M3 on my bumper. The car just falls flat and almost dies.

 

Driving slower or putting a fuel cell did resolve the problem? Any quick fix, like extending the tube or something? Both options dont sounds too ideal for me, haha.

 

Found something like this which may fix the problem:

Internal surge tank

 

Another version i have been looking at http://www.034motorsport.com/fuel-in...k-p-21527.html

 

Those look like they need a return line to the tank so you'll need a different rail, plus cost is so close to fuel cell...

 

Interesting...That's a good solution over a fuel cell. I never knew they had stuff like that. It's a kind of like a dry sump for your fuel.

 

My car started doing this as well. Has any company designed a motive flow pump that we could install in the driver side half of the tank? I saw one in my moms c230 which has a similar fuel tank design and it looks like a brilliant solution to the problem and theyd be cheap to make since they use pressure off the stock pump to venturi fuel from the opposite tank back into the tank with the pump.

 

The Spec Z guys are doing this. I did it earlier in the year on my car too. I just bought an OEM pump and wired it up to a switch. It resides in the drivers side tank and pumps fuel to the passenger side tank where the fuel pump is that feeds the engine.

 

Write-up on it?