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FD gas tank baffle and slosh problem

Old 10-17-03, 03:52 AM
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FD gas tank baffle and slosh problem

I could not find any discussion on this, only about fuel cell, which I don't want to buy.

I found out that my gas tank baffle is not in good shape anymore, it just float around in the tank, and even knock down the gas level sender.

New tank cost about $300, and you still have to run at least 1/3 or 1/2 tank full to prevent slosh.

Would it work if we stuff the gas tank with fuel cell foam?

They are pretty cheap compare to buying new tanks.
http://www.fuelsafe.biz/fuelsafe7.htm
http://www.fuelsafe.com/FAQ.htm

Anyone has ever try this? Any suggestion on how to do it? Any problem with foam getting sucked into fuel pump or clogging it?
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Old 10-17-03, 05:09 AM
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just buy the fuel resorvior from rotary extreme for a fix, or make your own, it really is not that hard to do
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Old 10-17-03, 07:33 AM
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The foam may be a good idea but you'll need a bunch of it in order to fill the tank. At that point I think the outboard sumps or fuel cells are competitive.

The foam will not crumble and go into the pickup.
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Old 10-17-03, 09:15 AM
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I was going to do that, but I really want my level sensor to work. Might still do it, the level sensor doesn't want to work at the moment anyway.
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Old 10-17-03, 11:29 AM
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Look at the price. The foam are cheap they could be as low as $10 from Summit racing.
I think I just need 4-5 of them.
http://store.summitracing.com/partde...t=SUM%2D290190

Compare $50 to new tank $300 or Fuel cell + stuff to make it work $500+? or Fuel Resevoir $500+?

And the foam would prevent the fuel slosh, and I can keep my old tank without the baffle.

Last edited by reza; 10-17-03 at 11:31 AM.
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Old 10-17-03, 11:44 AM
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Originally posted by reza
Look at the price. The foam are cheap they could be as low as $10 from Summit racing.
I think I just need 4-5 of them.

You must fill nearly the whole tank. Just a few will do nothing for you, the fuel will just slosh "around" the few foam blocks. If your idea is to just surround the fuel pick up with a few blocks of foam it won't work well at all.
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Old 10-17-03, 12:04 PM
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Yes, I will fill it up with the foam blocks, fill up the whole tanks. The only problem is the fuel level sender/float. It will not work.

The foam size is 4"x7"x15", right now I am estimating 4-5 blocks, do you think I need more? How many more?

http://www.speedwaymotors.com/produc...No=1&redirect=

Last edited by reza; 10-17-03 at 12:18 PM.
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Old 10-17-03, 12:35 PM
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With foam that large, you'll be decreasing your fuel tank capacity...
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Old 10-17-03, 12:43 PM
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Originally posted by SleepR1
With foam that large, you'll be decreasing your fuel tank capacity...
Not by much, the foam is mostly air. In a twenty gallon tank I'd be suprised if you lost more than half a gallon at the most.

Reza, I've neer measured the tank but just guessing I bet you'd need more like a couple dozen to nearly fill it?
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Old 10-17-03, 12:53 PM
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You won't need that many.

The foam is only supposed to take 5% of your tank capacity.

The FD tank has a big bulkhead running through the middle in front of the opening. You should only have to fill the space behind it around the pump, as the bulkhead only has a few large holes in it and will keep the foam in place in the back half of the tank.
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Old 10-17-03, 01:01 PM
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Is this bulkhead the baffle? My baffle is totally messed up, I can even take it out.
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Old 10-17-03, 01:04 PM
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Not the plastic bucket. Look forward from the hole, you'll see it. I kept getting my fuel tank sender hooked on it when I was trying to put my pumps in the tank.
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Old 10-17-03, 02:10 PM
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Originally posted by TYSON

The foam is only supposed to take 5% of your tank capacity.
The foam only displaces a small amount of your gas capacity, but nearly fills the entire volume of the tank. You're still supposed to fill the whole tank.
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Old 10-17-03, 02:15 PM
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I thought that means I can run less than 1/3 tank for autocross?
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Old 10-17-03, 02:18 PM
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Originally posted by DamonB
The foam only displaces a small amount of your gas capacity, but nearly fills the entire volume of the tank. You're still supposed to fill the whole tank.
I know, but that might be a little tricky with the divider in there. Filling the back half will at least help with the fuel sloshing.

I wish someone made a fuel cell contoured the same as the stock tank.
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Old 10-17-03, 02:20 PM
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Reza,

You can't do the foam mod and be legal for ASP. ASP only allows you to change the fuel pump and lines, not baffling or tank changes. You could run a fuel cell, but the allowance for that is based on safety and would require you to also run a rollbar.

Basically, you are stuck with the stock tank unless you want to spend $$ on a fuel cell and rollbar (I think you need a fire extinguisher too), or go to SM2 where you do other mods like the Rotary Extreme kit.
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Old 10-17-03, 02:22 PM
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My goal is to reduce cost. Well the fuel cell foam is primarily used in the fuel cell boxes to prevent explosion. It absorb fire explosion. So in place of baffle will be this foams.
Thus safety and performance too

Is it in the rulebook about the foam?
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Old 10-17-03, 02:32 PM
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If it's not in the rulebook, you can't do it. If you read the SP rules the only allowances are for fuel lines and fuel pump. Just because it doesn't mention foam doesn't mean you can do it. So, unless you can legitimately call the foam part of the fuel pump I don't see how it is allowed.

If you add a fuel cell the rules are very clear. It has to be at least 80%(maybe 75%) of the stock tank capacity, be located in about the same location (I think you can move it 6 inches, but I'm not sure), and you *also* have to do the rollbar and fire extinguisher. The only reason the fuel cell is allowed in SP is because of crossover rules with Solo 1.

I'd suggest reading through the rulebook though, as I'm only going from memory. SM2 rules are much more friendly than ASP.
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Old 10-17-03, 02:39 PM
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Jeff Hoskinson has said on the RX7 List that he might produce the baffles which are found in the 96+ FD.

A few of us on the list have shown interest in this but he hasn't posted what his plan is.

Jeff, are you listening?
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Old 10-17-03, 02:46 PM
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Baffles?

I would be in for some baffles.

Also Brian at M2 has mentioned that he has a "cure" for the starvation. Said he would post it on his site but I haven't seen it. It has been a while since I talked to him about this. At least a couple of years.

It would be nice to run events with less then a 1/4 tank.
What does a gallon of gas weigh?

Niles
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Old 10-17-03, 02:53 PM
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Re: Baffles?

Originally posted by SHPNOUT

What does a gallon of gas weigh?

Niles
I think it's 6 pounds? (maybe 8? Think it's 6 for gas, 8 for water).
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Old 10-17-03, 03:08 PM
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Running at a 1/4 tank would be nice. On grippy concrete I've had the car starve at 2/3 of a tank. My understanding was that on grippy surfaces you need to run 3/4 tank?
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Old 10-17-03, 03:13 PM
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Originally posted by AMRX7
Running at a 1/4 tank would be nice. On grippy concrete I've had the car starve at 2/3 of a tank. My understanding was that on grippy surfaces you need to run 3/4 tank?
If you're on race rubber that's about right. For autox I just leave it full; at least that way I know my weight distribution is always the same. Road racing can normally get away with lower levels because you don't have the sloshing that goes on in slaloms etc.
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Old 10-17-03, 03:21 PM
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Yeah, I run full or almost full for autocross. At the track I was starving with a little over half a tank. On street tires at the track I can run with less then half.

Niles
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Old 10-17-03, 03:32 PM
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So what is the verdict? No foam allowed in ASP gas tank?
Anyway, what is the part number of the new 99+ gas tank? I tried to call Mazda Motorsports, and they close all day today. Strange its friday, and I am working in the office, so must me some japanese holiday.
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