Rabbit GTI fuel pickup solution

J

JHackman

New member
I took my ITB Rabbit GTI to its first race last month, a non-SCCA event at No Problem Raceway Park (no kidding) outside New Orleans. Car ran nicely, but after a few laps began cutting out in right hand turns, coming back when straigtening the car out. Obviously this has to be fixed.

I am told the likely culprit is a broken in-tank pickup, leaving the fuel to be picked up on the right side of the tank. I have also been told that this happens to some extent with all Rabbits. So, would the best alternative be to:

Fix the stock pickup? I am guessing not.
Buy or build a better in tank pickup?
Or, add another pump and install a large diameter "fuel line" with bleed ahead of the stock pump. I called Denver and was told "they make some pretty large fuel filters" too. From what I was told surge tanks as a component of the fuel cell are OK, but with the stock tank installed things a little more in the gray area,with the dual purpose rule coming into consideration.

I am on somewhat of a budget, to put it mildly, but have to do something. Actually I probably won't run SCCA until spring, then going back to school, so I wouldn't run into potential rules trouble for some time.

Thanks,
Jeff Hackman ITB Rabbit GTi
 
I have had some friends that have had this problem. Mostly on their street cars (4 'rooco's a couple rabbits, a jetta, you get the point), but the race GTI never did it. We investigated and found that some cars had better baffles than other. You can see the baffles as I recall through the sender untit hole if you remove the sender. Might be worth it to go to your local salvage yard and find a tank that has the proper baffle set up.
 
I have this problem with my Rabbit when autocrossing. I run 13x7 wheels, so it corners hard, but not every right turn does it... I think just left to right transitions seem to slosh the fuel around enough or something. Only fix I've found is to keep the tank full, if I'm less than a 1/4 full, I have the problem.

I also recall a thread in the VW forum awhile back about a fix from an IT racer that solves the problem... me, I would just try to make my own baffle or improve the stock one. Maybe check the archives going all the way back.

PJ

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83 Rabbit GTI - future ITB

[This message has been edited by machschnell (edited October 19, 2002).]
 
This is a well known and documented problem w/ A1 VW's. My car does it, and so do several of the other ones I know of. There are a couple of options. My current one is to start the race w/ a full tank of fuel. In a 16 lap race at Summit Point (32 miles + 2 miles for the pace lap), I don't have a problem w/ 'burping'.

The large fuel filter solultion doesn't work w/ VW's as it's downstream of the fuel pump. What happens, is that the pump sucks air, and can no longer maintain fuel pressure.

The best fixes for this is either a new/repaired tank (I've heard they can be repaired for <$100) or through the use of a surge tank. I believe you can get new gas tanks from JCWhitney for ~$250. The surge tank setup can easily run that much or more if you start getting into aluminum tanks and AN fittings/hose. If you're going w/ a fuel cell, the surge tank is pretty much the only way to go.

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MARRS #25 ITB Rabbit GTI
SCCA 279608
 
Thanks for the info,

I think the "large fuel filter" suggestion was tongue in cheek, as the technical person in Denver (Sven?) and I were discussing reservoirs upstream of the stock fuel pump-in effect, a surge tank. His point was that a surge tank as a part of the cell setup (an attachment) was legal, but he wasn't so clear about use of a surge tank with a stock fuel tank. Hence, the "large diameter fuel line" question from me, and his "fuel filter" response. The rules do say any pumps and lines may be used, so who's to say whether the line the stock pump draws from has a lot more capacity than stock? Say a couple of quarts?

Sounds like this is an issue with or without cells, and a surge tank would be the best solution. I can keep it if and when I install a cell.

Also seems like an issue of "one less thing to forget." It was a pain trying to "burp" the air out of the stock filler to get every bit of gas in the car. Maybe with a repaired tank this would be better, but it sounds like it's still an issue. This particular track has a bunch of hard rights, and it's as much a safety issue as it is a performance one.

Jeff Hackman ITB Rabbit GTi
 
I had this problem on my ITC Scirocco.

I finally figured it out, and would guess that mine was typical. The stock tank has a plastic surge "chamber" and baffle combination. The pickup is located iside the bottom of this chamber. There is a rubber gasket sealing this chamber to the floor of the tank. In my tank this gasket had deteriorated. 1st symptom was a ruined fuel pump which choked on the gasket fragments. (OK - two ruined pumps since I'm a slow learner sometimes). 2nd symptom was inability to pick up below ~4-5 gallons in long right turns (Carousel at Summit Point). It seems that the absent gasket basically elininated the surge chamber as gas could just run out the bottom.

I suspect that a previous owner had used some magic gas additives which attacked the gasket, or maybe just 20 years in gasoline did it in.

Solution was a "newer used" tank with a good gasket - now will pick up down to ~ less than a gallon, verified by looking through sender access hole at end of a session at Summit Point.
 
This is a bit of a tangent but that kinda reminds me of the clever solution one of the Baby Grand drivers used to add more fuel capacity.

It seems that BG's can't run 12 race laps at Road America (standard race length) without running out of fuel, and the last mile is all uphill.

(RA BTW is a major gas hog cuz of the time spent at WOT)

The BG's are not permitted to change their Fuel Cell size per the BG Association rules.

But fuel lines are unrestricted......so.....just add about 20-25 feet of #10 Aeroquip and bingo, enough extra capacity to finish the race!


[This message has been edited by Greg Gauper (edited October 22, 2002).]
 
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