Fuel Starvation on High G Corners?

[larryn]

Hi - had an awesome day at the track yesterday, second in this car, but have been doing many events for many years and am usually one of the faster/quicker drivers out there.

This things gulps gas, and I went through nearly three tanks of gas over the day, but was only passed by Formula cars.

The problem: When below 1/4 tank, consistently in the same compressing and fast corner (~110mph), I would get an error that I couldn't read before it disappeared, but something about exceeding the car's capabilities, and fuel would cut - just for a few seconds. Same corner, same speed with more gas, no problems at all.

Interestingly, once on the same corner, same situation (< 1/4 tank) with receiving an error, except got a "Drivetrain Malfunction", and went into limp mode, which cleared on pitting, shutting off, then turning on.

I can only conclude it is fuel starvation, and I'll have to plan to make more trips to the gas pump. Has anybody else seen this? I never had this issue in my E92 M3 on that same track.

My car is pretty well set up with Dinan Stage 2, intake, exhaust, GC coil conversion, RS29's, 275/305 NT01s.. I was passing stock cars, GT3s, P Turbos, etc.. This car is damn fast out there...

[RacrX]

Not to hijack the thread, but- Any issues keeping the rear end planted in the corners? I keep reading about traction issues on the M4 an have my first track day coming up in a couple of weeks with it.

[larryn]

Originally Posted by RacrX

Not to hijack the thread, but- Any issues keeping the rear end planted in the corners? I keep reading about traction issues on the M4 an have my first track day coming up in a couple of weeks with it.

With the 305 NT01s? None. Roll on the throttle as you approach apex, and you're full throttle past apex. No spin at all.

[S65V8]

Yep, once I hit around 1/8 th ish I'll get a fuel cut yank for a moment, at which point I pit in and get gas lol.

[stranger]

Had the same issue

Once it gets down to the last bar before empty it starts

[CanAutM3]

Originally Posted by larryn

With the 305 NT01s? None. Roll on the throttle as you approach apex, and you're full throttle past apex. No spin at all.

^This

[jacobe92]

I take it you get on the track every time at minimum fuel to keep the weight down. ?. I do the same thing. My next Trackday will be on May 28 and it will have turns like you describe. I'll report back. This will only be my 2nd Trackday on my new F80. Cheers!

[Drive4Fun]

I have to fill up every session to avoid the fuel cut/drivetrain malfunction. If I don't start with over 3/4's on the same turn it'll cut out by the end of session. Same situation as OP. 25 mins out I usually burn around 7 gallons.

[larryn]

Originally Posted by Drive4Fun

I have to fill up every session to avoid the fuel cut/drivetrain malfunction. If I don't start with over 3/4's on the same turn it'll cut out by the end of session. Same situation as OP. 25 mins out I usually burn around 7 gallons.

The first half seems to go slower than the second half of the tank. I can do 2 x 20 minute sessions and be just a smidge under half. On the third session, I use that all up in 20 minutes. This thing can drink!

Thanks for the replies. Seems it is a standard problem. I only happens on high speed right handers, not on left though. The fuel pickup must be on the right.

[nicknaz]

7mpg is what i have been getting!

I would just keep it >1/4 tank and call it a day.... (I try to start sessions with >1/2 tank)

[S65V8]

+1 to the fact this car drinks gas when you're on it, I want to say it's thirstier than my E92 ever was at the track.

[CanAutM3]

Originally Posted by SROC5

+1 to the fact this car drinks gas when you're on it, I want to say it's thirstier than my E92 ever was at the track.

At the track, the F8X is definitely much thirstier than the E9X. There is a simple reason for that : it makes more power more of the time. That power comes from burning fuel. There is no way around that .

[FLOSS M]

I have experienced around 4 - 4.5 gallons per 25 minute session. I don't go out with less than 1/2 tank.

I had the drivetrain malfunction after a session when I started the car back up. It went away with a re-start. Dinan has a firmware update that addresses this and the car has been fine since

[coolmody]

I have the same issue. I can only get 2x20 min sessions before I need to refuel. If I don't and go for another session, I'll get the low fuel warning and the drive train malfunction errors which puts me into limp mode.

[Degobar]

Same thing happened to me twice in a specific track, always in the same left hand, 4th gear corner, which goes on for quite a while.
The first time I got no power for a second or two, but the second time around I got the drivetrain error message, and it went into protection mode. It cleared after exiting from the track and switching off the engine.
Took the car to the dealer to have it checked, they found nothing, but reset the electronics anyway.
I’ll keep my fuel level at >50% for the next trackdays...

[ashmostro]

This is disappointing to hear. Last 15% sure, but some are saying close to 50%?

This feels like a blundered fuel pickup design to me...

[afadeev]

Originally Posted by ashmostro

This is disappointing to hear. Last 15% sure, but some are saying close to 50%?

This feels like a blundered fuel pickup design to me...

No, definitely not 50%.

My F80 has gone through 5 DEs so far, and only saw one fuel pickup hiccup issue when gas level had dropped well below below 1/4 tank (1/6? 1/8?). Multiple runs at 1/4 tanks on multiple tracks = no problems.

Strangely, that one hiccup was on the main straight after long right-hander. No error codes, just a power delivery interruption. Either way +12 gallons of gas fixed that.

a

[Dweezil]

+1 with the hard higher speed left hander and less than quarter tank

[ashmostro]

Originally Posted by afadeev

No, definitely not 50%.

My F80 has gone through 5 DEs so far, and only saw one fuel pickup hiccup issue when gas level had dropped well below below 1/4 tank (1/6? 1/8?). Multiple runs at 1/4 tanks on multiple tracks = no problems.

Strangely, that one hiccup was on the main straight after long right-hander. No error codes, just a power delivery interruption. Either way +12 gallons of gas fixed that.

a

Ok that sounds more normal for a street car.

And the hiccup in the straight is what I commonly experience on other cars. Makes sense - the "bubble" takes a little while to make it to the injectors so it usually happens after the offending turn and not in it.

Thanks for sharing your experience.

[redpriest]

Originally Posted by Drive4Fun

I have to fill up every session to avoid the fuel cut/drivetrain malfunction. If I don't start with over 3/4's on the same turn it'll cut out by the end of session. Same situation as OP. 25 mins out I usually burn around 7 gallons.

This is kind of depressing. My friend in his 370z has this fuel cut problem, and meanwhile I've been laughing it up in my E92 M3 - is this going to be a problem when I get my F82? Is there a mod that can fix this?

[larryn]

Originally Posted by redpriest

This is kind of depressing. My friend in his 370z has this fuel cut problem, and meanwhile I've been laughing it up in my E92 M3 - is this going to be a problem when I get my F82? Is there a mod that can fix this?

Baffled gas tank or aftermarket redesigned pickup - or dual pickup design. Or.. get gas more often... as I plan to do.

I never had this issue with my E92 M3 either... I guess that I have to chalk it up as par for the course for a car that much faster on the track.. uses more consumables, tires, brakes, gas.

[FrenchBoy]

I can attest that larryn is quick out there. Nice driving buddy!