Fuel starvation

#21

For one car at VIR this weekend that had a fuel starvation problem it turned out to be a kink in the large vent tube coming from the fuel tank. It looked like it had been that way for years. After correcting it they had faster fill ups, got a full tank and no more starvation. The blockage was enough to cause a partial vacuum that affected the rate of fill and capacity. It seems it could also affect the rate of flow for fuel pump if it’s fighting a partial vacuum in the tank. Those of you who have changed the pumps and filters many want to trace out your vent tubes and check for blockage/kinks. Just a thought…

Seth

#22

Patton wrote:

Agreed.

b]Carter wrote:[/b]

I hate to bring this up, but how does the 318 (is) play into this? Parts can be moved from those cars (and vice versa) as well?

#23

IndyJim wrote:

[quote]What about fuel cells? I know the stock location, etc etc.

I’ve replaced literally every fuel related component in my including the tank. It is a 90 IS, one in tank pump. I’ve added a second pump as well, didn’t help.

Still starve out after about 4-5 gallons (45 min.). In the enduros I’m toast. I did 4 pits stops w/ fuel when everyone else did one.

My options at this point, build a new car, or try out a fuel cell. I’m going to the cell.

I have a 12 gal. well cell, the easiest way to go. However I’ve been sent to the CCR 15.4 for fuel cell rules.

Basically they say - no minimum. So theoretically (if I’m reading right) I could add a 22 gal cell and drive forever?

Carter - what are your thoughts on this since I want to stay legal and not have to do rework, at least here since it is $$$$.[/quote]

This is a good point, considering the new enduros. Up to now, it wouldn’t have been an issue.

Before you do it, give me a few days to do some research.

Carter

#24

This is what I’ve been able to come up with.

Here is a good BF link that shows probably the two most common setups (at least from what I’ve seen).

Opt 1 - spare tire well cell 12 gal (what I currently am planning on and have). There is also a 17 gal made for e36 that will fit in our trunk as well, just sits up higher and is $$$$

Opt 2 - cut out the spare tire and make a ‘box’ drop in 15, 17, 22, etc rectangle. I would have liked to have gone with the 17 ideally obviously the installation is a little more dramatic here.

Opt 3 - some type of custom cell for the stock location again big $$$.

Our specs simply say “fuel cells are allowed” which then goes to the NASA CCR. That allows trunk floor modification, specifies placement, and gives the spec for the type of fuel cells that are approved. But still pretty vague.

#25

Before making the decision, consider that there are some guys with cells already. Didn’t somebody put one in AT Road Atlanta last summer? Wouldn’t want to screw anyone if it can be avoided.

#26

My car was hurting leaving the two slower corners leading onto the bridge straight and Oak tree up the hill on the back straight. VIR Full and Road Atlanta are pretty much out of the question. A decent momentum track it should be fine, but probably too much of a pain in the ass to worry about. The 318is only came with the smaller tank, pretty obvious you’d want the larger tank… I ran easily further in the enduro than any other car and has just started to starve a bit. I came in because I was tired as hell and had a cramp in my leg, I had a couple spins due to the resulting loss of concentration so it was time to come in. With the big tank that 4 hour enduro at the end of the year is probably a 1 stopper.

With weight in the car it was really hard to pull up the hill in the back straight. You lose alot of momentum during shifts, -3-4-5 was all done on the back straight. If you are in gear at the top of the revs the car pulls right along. When you shift you lose 3-4 car lengths at least while you are out of the power. I pulled weight out of the car (2450# maybe and called it a PT car) during the Enduro and ran a 2.22 which is decent considering I suck at VIR. There seems to be an issue with my brakes, I can’t go as deep confidently as I used too and both Nick and I flat spotted RF tires. I’m going to tear the brake system apart clean out the calipers and install a fresh master cylinder and anything else that can moves in the system.

#27

Ireland sells a $55 “fuel accumulator” that holds a pint of fuel for dual pump systems. There are some folks on Bimmerforums that said nice things about it. Sounds like a lot less hassle then a fuel cell, but is it legal?

And a nice fuel call install here:
http://e30m3performance.com/installs/installs-1/fuel_cell/cell_1.htm

#28

BTW, My intended solution for the fuel tank was this before I realized you couldn’t run the big tank in the 318 under current Regs. The small 318 tank is shorter on the driver side so I’d have to get a custom pump to sit in the bottom.

If you allowed update backdate of tanks. I’d cut the top out of an old tank to remove the hole and mounting for a stock pump. Weld it into the opposite side of a fresh big tank, rules say you can fit any pump, they don’t say how this needs to be done so this is probably the cheapest. That way you can run two pumps in series like we do on the E36’s.

#29

mskeen wrote:

I ‘think’ that everyone / anyone that has done this has gone with the well cell since that is a pretty straightforward installation and in the 2007 rules all that was allowed. But agreed I think that is the minimum to be allowed (imho).

This year it appears to be broader so I guess just looking for a clarification if bigger cells are allowed and if so does that include the necessary modifications to the body, etc to make them fit / work.

I’d also say that I am in favor of the back / post dating as well.

#30

My point is that the update backdate rule wording needs to be thought through since the 318 came with a 4.10 right? Same with other E30’s…Etc, etc.

#31

Craig, you are correct…no swapping of parts between 318s and 325s. This woud keep Keener with the same small tank and allow racers to continue to pick on him.

Put best bumper to best bumper on a e30.Best tank to best tank. Are there other obvious parts where the post-87 cars are better. If we can pinpoint those it will make Carter’s consideration of a back/post date concept easier to grasp.

Audience, any other parts?

Regards, Robert Patton

PS, Jim I’ll split the cost of the accumulator thingee with you as I hate to see you complicate your life with a fuel cell.Likewise it complicates the series’ rules.

#32

Gasman wrote:

I agree.

Since Carter asked for thoughts form the group.

I have done some HSR enduros (and crewed for a lot) and they have a few rules that aleviate the problem of tank/cell size.

  1. In a four hour enduro they require at least 3 stops and the first 3 have to be at least 5 minutes.

  2. No single driver can drive more than 45 minute at a time.

These rules tend to minimize the effects of cars with large tanks having the ability to go 2 1/2 hrs. on a run. Secondly, it alleviates excessive driver fatigue and the accidents that tired drivers can cause. Even us fat old guys can go 45 minutes. Finally, the 5 minute pitstop rule reduces the effect that a team with an efficient crew can have over a husband and wife team who have to put fuel in and change tires themselves.

FWIW

Don

#33

Don and others, I too agree that a manditory 5 minute rule would work. But that is not a decision that e30 rules makers can do?
Stick with those things that e30 can control?

Regards, Robert Patton

#34

My problem wasn’t the 5 min. The 3 hr enduro’s require one. Everyone did that one, I just added 3 others…

So my first goal is to at least get down to the 1 pit stop, then work from there.

Patton - thanks for the offer, I’ve heard two things on the accumulator 1) old cars only, not sure why this is a requirement but Jeff himself told me that. May have to do with the transfer pump? 2) they don’t work either (that is hearsay but that is what asking around told me).

#35

As for the fuel starvation, I chased this for a couple of events. Initially I thought it was rust in the tank, so I drained the tank and replaced the filter multiple times. Each time,the car would run fine for a few laps before the problem would show up. The next time out it would run fine again for just a few laps. I’d drain the tank, even filtering the gas to look for large debris. At Road Atlanta last year we pulled the pump out to inspect the pickup. The pick up and cup were both clean. Finaly we realized that the large rust was settling on the bottom of the tank while the car was still but after a few laps would get stirred up enough to clog the pickup. At the track we tried jacking the car up on one side, sticking an a extention with a rag ducktaped to it as far as possible on both sides to rake the rust out. All of which did not help. Finnaly we decided to drive down to Summit Racing and buy a cell and external pump which we installed in the middle of the night. Problem solved! Well sort of.
It got us through the race, but one of the guys suggested that the spare tire well, where it was mounted, was a crumple zone for the car. Ultimately I decided the factory location was the safest place for the tank and that the center of gravity was likely better there also. I removed the cell and sent the OEM tank to a local radiator shop to be vated and sealed. Its been great ever since. I do have a problem with it filling slow now, so I need to trace down all the vent lines. I think you mentioned replacing the tank once, if you have replaced it with a doner cars tank, theres a good chance it is rusted too.

#36

I don’t see how a 5 minute rule is going to make any difference. this issue is not how fast you pit it’s how many pit stops in a three hour race.

the cars with 14.5 gallons generally have to stop twice and the 16.6 gallons once, so the 5 minute rule would put that group at 10 minute pit vs 5 minute pit. Plus enduro racing is not just the driver but the pit and pit time. So the 5 minute rule is taking a big part out of an “enduro” event.

Also both my car and carter’s have 14.5 gallon tanks, so it a bit random as to which tank you have. J. Allen’s is 16.6

Carlton

#37

I agree with Robert that enduro rules shouldn’t be taken into account because they will vary. But fuel cells accomplish both a longer duration/capacity and a fix for starvation, so it seems to me as just one voice here that the rules already provide for a solution on both issues. Maybe someone can explain why that leads us to unlimited updating/backdating of bumpers or whatever else, but I do understand why that might be desirable if you have a good budget, access to lots of parts, a garage, a lift, and time to play with options.