At The Track Fuel Issue

I have tracked at LRP in CT 5 times in the last 7 weeks. When I enter Big Bend (a hard, hard right hander after a long straight), I notice coming off the 2nd apex the car wants to shut off. Stutters, catches, about 2 times. This only happens when I am about 3/8 of a tank or less by my fuel guage. I know the guage is accurate cuz I've run it down to E and had to put in nearly 16 gallons (I know that's bad). So I don't think it's a guage issue, but more of a pick up issue. The fuel filter is brand new. Anything over 1/2 tank, no problemo. Just when I get about 1/8 tank lower than 1/2, that's when it starts happening & gets progressivly worse as the fuel level drops. No smart a$$ remarks about keeping the tank full please. Just want to know if my fuel pump or transfer pump could be at fault or if anyone else noticed this phenomenon. Fuel pressure is dead on when tested no matter what the guage reads & this only happens at LRP. Thanks, Chas

Fuel starvation. Your fuel pickup is on the passenger side of the tank - hence, when you make a sweeping right-hander, your fuel pulls to the driver side. Of course, when you get low enough, in your case 3/8 of a tank, the pickup will have nothing to pull through it, the residual fuel in your lines gets quickly consumed, and you'll experience exactly what it is that you're experiencing. There are two things you can do: 1) keep it above 3/8 at all times (which is annoying) or 2) purchase a fuel baffle. The M3 comes with one stock and the part is completely interchangeable into the non-Ms (It's cheap too). I'll see if I can source one...

-Edit-

Here:
http://www.rogueengineering.com/Merc...ry_Code=BMWGAS

The M3 baffle helps a little, in my case fuel starvation went from a little over 1/2 a tank to a little under 1/2 a tank. It's a band aid, but not a solution.

Originally Posted by vaio76109

The M3 baffle helps a little, in my case fuel starvation went from a little over 1/2 a tank to a little under 1/2 a tank. It's a band aid, but not a solution.

Duh

Chas, posted some pictures way back here. Might give you an idea how it is installed.

Thanks to all for the advice & to FTWeisse for the link. I guess I can try the fuel baffle for now. Maybe I will get to less than 1/4 tank b4 fuel starvation occurs. Mr Paddle.Shift, thanks for the pics. vaio, I do also realize that this might be just a band aid approach, but it just might be enough for me to get thru a track day without stopping at the track pump & paying $6/gal for an extra 5 gals of fuel so that I can finish my last sessions. Thanks again to all. Chas

There are some on the forum who get the P0171 and P0174 codes due to this condition. I have found that hard driving on the street with under 1/4 tank of fuel will give me the "lean bank" codes. If I top the tank and reset the codes they do not return.

After I installed my SC'er, which of course increased fuel requirements over stock, I started running into fuel starvation problems below a half tank. Usually when turning right but also under hard straight line acceleration (starting ~ 1/4 tank). Never ever had a problem when there was more than 1/2 tank of gas.

I initially installed the M3 tank baffle based on a few forum posts I had seen. Slight improvement but not much. I ended up solving the problem completely by also installing an M3 fuel pump. While the 330 pump was providing adequate flow to the engine, it wasn't providing enough return flow from the FPR for the sucking jet pump to siphon fuel from the driver's side over to the pump side. Haven't had a single problem since the upgrade almost a year ago.

Beyond the M3 pump + baffle, the only other thing you can do is move to a dual pump setup. Unfortunately these setups don't work with the stock fuel gauge. Not a problem for a dedicated track car but I expect most street/track cars will want to preserve the stock fuel gauge.

Unless you have a separate pump transferring fuel from the drivers side to the passenger side, you will be running into fuel starvation issues at certain tracks. After 9 years of going through this, I can pretty much pinpoint where an e46 with a stock tank will cut out at tracks that Grand-Am runs at.

I have fabricated baffles, used the M3 baffle, fabricated 3 baffles plus the M3 baffle and nothing ever worked. It just comes down to the amount of fuel going over to the drivers side of the tank and a pump that can transfer it back fast enough. I finally figured out a solution that works for me but it requires a bunch of maintenance. Thing is, I got the maintenance part down and i don't mind spending the time between races doing this. The benefit I have is that I got a car that handles the same no matter where the fuel level is. It only changes weight distribution by 0.1% from full to empty.

I had the same problem at LRP, and I did the M3 baffle and it definitly helped. If you start with a full tank beginning of the day, you'll be fine for the rest of the day if you do this baffle. Otherwise the problem starts to creep up in your 3rd session and by the 4th one forget about it. I did a DIY on bimmerforums.

http://forums.bimmerforums.com/forum....php?t=1263979

Originally Posted by drivrswntd

I had the same problem at LRP, and I did the M3 baffle and it definitly helped. If you start with a full tank beginning of the day, you'll be fine for the rest of the day if you do this baffle. Otherwise the problem starts to creep up in your 3rd session and by the 4th one forget about it. I did a DIY on bimmerforums.

http://forums.bimmerforums.com/forum....php?t=1263979

Jay, Since my M3 baffle is set to arrive today, I cked out your diy link. Seems pretty straight forward. Thanks for the link to your vid. Chas.

Originally Posted by drivrswntd

I had the same problem at LRP, and I did the M3 baffle and it definitly helped. If you start with a full tank beginning of the day, you'll be fine for the rest of the day if you do this baffle. Otherwise the problem starts to creep up in your 3rd session and by the 4th one forget about it. I did a DIY on bimmerforums.

http://forums.bimmerforums.com/forum....php?t=1263979

Jay. Just finished installing the M3 baffle as per your link. My AllData was very vague on the fuel pump R&R, & your pics helped a lot. Really didn't take more than 1/2 hr, but installing the rear seat was a pita. It didn't want to clip into the front latch points. That took me about another 1/2 hour b4 I figured out what tricks to use. Anyway, no big deal, since my lead tech is much bigger & burlier than me & I know that it would have taken him 2 min to clip the rear seat into the brackets. I just didn't wnat to hear him razz me on such a simple procedure. Big guys generally win. Hopefully, this baffle will help me get me thru the entire track day on Wed with no fuel starvation. Will keep everyone posted that contributed to my thread.
Jay, Thanks for the pics & diy. Chas

Absolutely drivrswntd. It starts at the 3rd session & progressivly gets worse on. The M3 baffle is what I think I will try 1st. Hell, it can't hurt. If needs be, then I will progress to the suggestions from the other members of the forum. Thanks to all. Chas

Originally Posted by ChasCan

Absolutely drivrswntd. It starts at the 3rd session & progressivly gets worse on. The M3 baffle is what I think I will try 1st. Hell, it can't hurt. If needs be, then I will progress to the suggestions from the other members of the forum. Thanks to all. Chas

If you do the M3 baffle it will definitly get you through the day. i was at LRP on 5/1 and I didnt have any issue's with the baffle installed now.

Originally Posted by drivrswntd

If you do the M3 baffle it will definitly get you through the day. i was at LRP on 5/1 and I didnt have any issue's with the baffle installed now.

Missed you at LRP on 5/1. Didn't register in time. Am going again on 6/2, 6/14, 6/17, & 6/26. Maybe we can hook up. Chas

M3 baffle helped me a lot too.

Just ordered the baffle for the M3 fuel pump from my favorite BMW dealership. It will be in on Thurs by noon & will have it installed by my next track day at LRP (Jun 2nd). Will keep all of you helpful forum members posted on how well it worked. Thanks for everybodys input. Chas

It is definitly really easy. Do it on like a 1/4 of a tank though, I was stupid and did it with like 3/4 of a tank.

Just another low tech thought, bring an extra gas can and top off when you can also before your later runs. Unless of course thats not allowed. One of these days when I am employed again I will make an LRP track day. Cant wait to go up and watch the Turner boys race this weekend.

Originally Posted by mtmactom

Just another low tech thought, bring an extra gas can and top off when you can also before your later runs. Unless of course thats not allowed. One of these days when I am employed again I will make an LRP track day. Cant wait to go up and watch the Turner boys race this weekend.

I bring a 5 gallon can with me to LRP and Monticello since there is no gas fill ups near by. I didnt end up needing it when I was just there though so that was a good sign.