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Ideal surge tank design for DSM road racing

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The rulebooks I've seen for racing typically say fuel in the interior of the car has to be firewalled off.
 
So update on my fuel surge tank. I have ran it a total of four days, but only two days did I actually push it. The first day I used it, only after like three gallons down I was getting weird cutouts on the track that felt like either an electrical short or the fuel sloshing away from the pick-up. I couldn't find anything electrical so I assumed it was the fuel surge tank just not doing its job, and so for the rest of the weekend I kept the tank fully topped off and didn't have the hiccups again.

I have good news though. Today I decided to test it again, not filling up until I ran into sloshing issues, and today I used about 11.5 gallons of fuel before getting any hiccups. So the 034 Motorsports so far is working for me.

I don't have any datalogs unfortunately showing how many Gs I'm pulling and for how long. I can tell you I am turning many turns faster than cars liks Z06's with R-compounds. My car has Andrew Brilliant's aero on 285-wide Nitto NT05 street tires. So we'll see as I increase my grip, braking, and acceleration just how well the tank holds. Oh, also this was on Virginia International Raceway. All of this is hard to translate into "will that tank work for me with my setup on this track?" but it's the only data I have for someone to try to relate to their situation.
 
I have plans of mounting the 034 Motorsports surge tank as well - it's been sitting in my garage for months now, maybe longer. I hope to start turning a wrench on it soon. I have a pretty good idea on where I want it to go. I'll do a full write-up when it finally goes in. Hope to have the same positive results.
 
It's possible I confused an ignition issue or something electrical with fuel pick-up issues. The next day I had similar power loss and when I filled up had only used 7.5 gallons. So it's possible in my setup I may have been able to get down to the last drops. I won't know without more investigation. For now at least I can confirm I can use 11.5 gallons in my best state so far which may prove useful information for other track drivers.

I'll be looking into things this week and hitting the track again this weekend, though a different track (Summit Point). I'll post any more data that I gather.
 
This may be a dumb question, but is there a purpose for a surge tank other than being able to run low fuel in high-G corners?

I've never really had a problem with fuel starvation (stock tank) until after the fuel light comes on, even with massive amounts of grip (albeit no areo). And as far as I know, fuel starvation doesn't cause any issues other than effecting the stopwatch. So I just make sure I have > 1/8 tank before heading out for my timed laps. :idontknow:
 
I hit fuel starvation as soon as the gauge dips below 1/4 tank, and it really hurts times. Unfortunately SP rules do not allow a surge tank :-(
 
It's to be able to use the fuel you have without interruption, yes, but also so that you don't have to carry around excess fuel, which is dead weight, that you might not need for your particular task.

It's awesome that in your auto-x events you aren't hitting it. I'm envious. The unfortunate reality is that in road course we often do have starvation early on even with minimal suspension upgrades due to the designs of our tank. Like ACM I would start to see starvation with as little as three gallons used when I had I thin 245 tires, 300hp, and some basic suspension upgrades (a very mild setup). This situation presents two problems for me personally:

1) I can burn more than three gallons in a single track session. This means I can hit starvation before I'm ready to come in and that's wasting my precious (and expensive) track time!
2) In order to use the three gallons I need to have 10+ sitting in the tank which is now just dead weight because I can't access it reliably. 10+ gallons of fuel weighs a lot! This matters to me because I am doing time trial and it affects the stop watch :)

An alternative to the surge tank could be baffling in the tank or a better designed tank, obviating the need for a surge tank outside the tank, but that's more difficult and not readily available to us. So people choose the easier surge tank route.
 
I have been running my custom built surge tank since last summer, and it's awesome! I can pull hard g's right to the last drop, and the first sign of cutting out, is when the tank is bone dry.
 
Actually I was making reference to my experience in time attack as well. Maybe it's track dependent as I've only run at AMP (next closest track is 15 hours away), but it really hasn't been an issue for me even with the big sticky 275 width r-compounds.

I guess the 15-20 lbs weight reduction in fuel (in my case) might help, but then again I'm hauling around a 20-30 lb trailer hitch plus most of the interior is still intact, so perhaps I'm not quite at the surge tank stage yet. :D

Thanks. I just want to make sure there wasn't an engine health reason behind it (like a dry sump for instance).
 
It's probably not as big an issue with your saddlebag style tank, but for us running a 1g AWD tank, left turns can be brutal with even four or five gallons in the tank. I'm not 100% sure, but isn't running out of fuel under boost normally considered bad for the engine?
 
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Scott, I actually did not know you did anything but auto-x. I think the times I've run across threads you were in they were related to auto-x if they were anything racing related, and then there's your avatar with the cone :) Please pardon my assumption.

I'm a bit at a loss how you haven't experienced the problem because I'd imagine on your 275 r-compounds you're pulling as much g-forces laterally as I am with the aero and the street tires, and braking should be comparable and I bet you greatly out-accelerate me. Certainly an interesting data point. Maybe you have a special Canada-only gas tank with baffling :) I have no idea...
 
No problem John. I actually won a class title at the national time attack championship in 2009. Been hitting the road course in my DSM since 2003 (and autox since 1999).

But again, only at the one track; so that may be a factor. Or my gas gauge may be off. LOL

Anyway, it doesn't matter. Thanks for sharing your setup with us. I love reading threads on how DSMers are preparing their cars for road course duty.
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Just to chime in and say my plans for the surge tank was mainly to be able to run down below 1/4 of a tank without fuel starvation. It was a big problem of mine the last few times. If I didn't start with a full tank I couldn't run a full session, and running with a full tank is far from ideal for lap times.
 
you guys look into the foam stuff?

RCI Racing 7050A - RCI Fuel Cell Safety Foam - Overview - SummitRacing.com


I've seen it used in circle track race cars. Just shove it in the tank and it's done. Just get the bigger foam and shove it so it won't get in the way of the float for the gas gauge.

BTW, doesn't the 2g have a hump in the middle of the tank so pickup is wierd? I would be concerned about pick up on both sides. I would actually run a pick up hose to the bottom of both sides and T into the pump. Which also brings up the question of if you have an aftermarket fuel pump do you have it down far enough for pick up?
 
you guys look into the foam stuff?

RCI Racing 7050A - RCI Fuel Cell Safety Foam - Overview - SummitRacing.com


I've seen it used in circle track race cars. Just shove it in the tank and it's done. Just get the bigger foam and shove it so it won't get in the way of the float for the gas gauge.

BTW, doesn't the 2g have a hump in the middle of the tank so pickup is wierd? I would be concerned about pick up on both sides. I would actually run a pick up hose to the bottom of both sides and T into the pump. Which also brings up the question of if you have an aftermarket fuel pump do you have it down far enough for pick up?

I admittedly only investigated fuel cell foam briefly. I actually thought you had to have it cut for a particular tank shape and didn't have the option of shoving pieces at a time into a tank. It all seemed a bit difficult to do and I had no idea about the efficacy. Since I knew a surge tank works, and is a common solution in the world of time attack, I just decided to go that route instead. Would be cool to know if shoving bricks of foam in works :)

Yeah, the pickup is an issue on both sides like you said. So any sloshing issues in-tank to be solved would need to be solved on both sides.

In regards to the location of my pump, it is mounted exactly where a stock one is, so it's as far down as I think you can get. Might not be the case though as I haven't looked to see if the stock position could be lowered any further. I couldn't tell you if there's anything to be gained by trying to lower it, but again maybe that's something to look at.
 
I am running into this on my 1G in auto-X hard left turns with under 3/4 tank sucks!

What about dropping the tank, cutting it open and welding in a baffle plate? seems to me that would be the cheap fix??
 
Wow. This must be my first post in ~4+ years or so. I've been lurking my subscribed threads (circa 2007-2008), and it's great to be back ... !

Anyhow, I like the 034 Motorsports surge tank idea. Placing it where the battery tray used to be on my car sounds like a good solution. I was originally going to split my stock tank and put baffling in there to help my Walbro 255 keep some fuel in the corners.

It is still quite expensive, though. I'm looking at around $523, with AN fittings and the Bosch pump.
 
Wow. This must be my first post in ~4+ years or so. I've been lurking my subscribed threads (circa 2007-2008), and it's great to be back ... !

Anyhow, I like the 034 Motorsports surge tank idea. Placing it where the battery tray used to be on my car sounds like a good solution. I was originally going to split my stock tank and put baffling in there to help my Walbro 255 keep some fuel in the corners.

It is still quite expensive, though. I'm looking at around $523, with AN fittings and the Bosch pump.
It is a good chunk of change, but it's probably one of the best options out there and it's still cheaper and easier than dealing with a road racing spec fuel cell (which, to stay legal in NASA would need a bladder). I have one of these 034 Motorsports surge tanks and believe me, it's better than anything else I've seen available. One of these days I'll get around to installing it.
 
I had been planning on mounting the surge tank under the car in a spot that would be tough to access. After seeing redhotridur's install in previous posts I'm wondering if mounting it in the hatch and building a sheet metal enclosure wouldn't be a better solution. I could do it using screws for easy access. Would that be considered safe? And would it be considered a "firewall" to meet the NASA requirements?
 
Im going to grab the tank out of my spare car and split it, put in baffling and weld it all back up. I'll probably put a sheet with a trap door in it opening to the drivers side, front to back about middle of the tank leaving the top 2 inches open, then put another sheet horizontal with a trap door opening down and with a cutout for the fuel pump and sender. I still have the auto swap and air-water intercooler re-design to do before I get to this though. Figure since I got most of the parts and metal already it should only take a day to do all the welding and not cost me but $50 or so.
 
See, that's what I planned to do. I've done it before on my brother's old '87 Corolla when we did an SR-5 to GT-S conversion (had to replace the fuel pump and patch up some pinhole leaks in the gas tank while we were at it) and it was relatively easy. My old man's pretty handy with a welding torch, but that was ~10 years ago ...

Buying up the necessary aircraft fittings to make everything work will get expensive, too, and there's nothing I hate more than getting steel braided lines onto their fittings! Still, this seems to be the most logical solution, provided you can keep the Bosch pump in the swirl tank fed. I suppose a Walbro 255, or even a 190 could handle it (especially on zero pressure), but would a stock pump be able to keep up?

Also, how would the wiring work for the swirl pot pump? Just tap it up to a 12v switched power to turn on as soon as ignition is switched on?
 
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