apparent fuel starvation on track

[dsacco]

First off, Hi:

 

I recently was looking into ordering a CSR and stumbled across a 2005 superlight R with 900 miles that I picked up. The thing has been a blast. In a few months I have put over 3 thousand miles on it and recently drove it from Dallas to Aspen with my wife for LOG 27. It performed great. I have had it on tracks (tws in college station) with big sweeping turns and it performed well without problem. Here is my question - on tighter tracks (msr cresson) it seems to have fuel starvation in tight right or left hand turns. The rpm drop and the car actls like it wants to stall but doesnt and will fire back up with some gas when the car is "flat". This doesn't happen with accelerating in a straight line. Any ideas? I searched and some electrical issues were suggested but it seems to be a more mecahanical problem with fuel pick up. I was wondering if a fuel cell would fix this problem, although I don't want to put in a fuel cell and still have the same issues.

 

thanks in advance

 

David

[Al N.]

David, welcome...did you buy that Black one from Jeff Sloan?

[slngsht]

Hi, and welcome aboard...

 

do you know anything about your current tank? Can you take off the filler neck and take a look inside to see if there is any baffling in it at all?

 

Does this happen even when the tank is full?

[scannon]

My SV has starvation issues if I let the tank get down to 1/4 indicated on the gage. I am assuming there are no baffles in the tank. I seem to recall there being some kind of "swirl pot" available to put in the tank to fix the problem but so far I usually just go out and fill it up again when it gets that low.

 

This was the reason I stopped giving rides to the Boy Scouts volunteers at the LOG27 track day. It was late in the day so I just loaded it on the trailer and hit the road.

[Al N.]

Having just removed the sender and fuel pump from a caterham injection tank (so I can really dry it out/clean it out before shipping to the buyer), I can say that there is at least one baffle in the tank...on the right side about 7 to 9 inches in from the right tank wall. I will check to see if there are any others...

[Titus]

Flyin Miata found that they had a similar problem with their Westfield, so they installed a swirl tank on the scuttle.

 

http://www.flyinmiata.com/westfield/images/IMG_7294.jpg

[dsacco]

Thanks for the thoughts. Unfortunately, it seems to happen with the tank full as well as empty. Our exige develops this issue on left handers with about a quarter tank. I like the swirl tank idea, seems straightforward, although I have to admit I never heard of this before. I purchased the car from a guy in houston. Apparently he rarely drove it. It is the car featured in the LOG 26 program. The car was originally built by Jeff Sloan and company at British Auto in Fort Worth. I love the car, but I have to get this sorted out to be able to really explore the cars limits (high) and my own (not so high). Thanks again for the replies.

[Birkin42]

I would assume you would need a 2nd fuel pump between the swirl pot and the engine? If not, how does this work?

Is there a fuel line out of the swirl pot from the bottom? Is that the line we see behind the pot at the bottom?

 

I know that Birkin's stock tank have only minimal baffling and have an issue with fuel starvation on the track when the tank is getting low.

I was going to add a surge tank near the fuel tank. I was going to feed this with a low pressure pump from the main tank. Overflow from this surge tank would be routed back to the main tank. I would run the main fuel pump from the bottom of this tank to the engine. The return line from the engine would go back to the surge tank. This makes sense to me but maybe there is a better proven way to do this.

[Titus]

  Birkin42 said:

I would assume you would need a 2nd fuel pump between the swirl pot and the engine? If not, how does this work?

Is there a fuel line out of the swirl pot from the bottom? Is that the line we see behind the pot at the bottom?

 

I know that Birkin's stock tank have only minimal baffling and have an issue with fuel starvation on the track when the tank is getting low.

I was going to add a surge tank near the fuel tank. I was going to feed this with a low pressure pump from the main tank. Overflow from this surge tank would be routed back to the main tank. I would run the main fuel pump from the bottom of this tank to the engine. The return line from the engine would go back to the surge tank. This makes sense to me but maybe there is a better proven way to do this.

 

Your description sounds just about exactly what Flyin Miata did with the one pictured. A low pressure pump fills the swirl tank from the main tank and a high pressure pump pulls fuel from the bottom of the swirl tank.

 

Edit: Here is a link to where they talk about it.

[Al N.]

To confirm...Standard cat tank has 2 baffles about 6 - 8 inches in from the sides of the tank. I took out the pump and sender from my old tank and looked around.

 

-Al

[JohnK]

Recently finished fabricating a sump to prevent fuel starvation when cornering and found this

http://www.autoperformanceengineering.com/html/pickups.html

while I was in the process of finding a replacement for the "new" Denso in-tank fuel pump that came with my "kit" and lasted all of 500 miles.

 

This "sounds" pretty good, and is well documented

Does anyone have any experience?

[WestTexasS2K]

Yes I've used those. They blew my supercharged engine the first few laps on the track from fuel. You better off with a remote sump. I found a good one that I posted here before. I'll have to look it up and repost. It's the best solution I've seen off the shelf. A bit pricey but it's excellent quality and cheaper than a damaged engine.

[1turbofocus]

Have you installed a temp fuel psi gauge to see whats happening to confirm it is a fuel psi problem

 

It sounds like it is to me but I like to know 100% before I go throwing parts at it

 

Tom

[WestTexasS2K]

Here is a good solution IMHO. http://www.intengineering.com/integrated-engineering-billet-surge-tank-submerged-044-pump.html