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Fuel cell mounting pics and questions...


JMortensen

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Jon - New to the site and to Z's. It has been a wealth of information.

 

I went down a similar but slightly different path. I'm using the same fuel cell, but chose to mount it so that I could adjust the height and angle. I spent some time with the SCCA GCR and our local Midwest Council rules. 6 inches of clearence from the ground at ride height is required. Since I didn't have a lot of experience with these cars I thought adjustable was the best.

 

I agree that getting hit in the rear would be an issue with this design. Just hoping that doesn't happen. I did add bracing at the lower edge of the rear valance and added a jack point for the rear of the car.

 

Thanks for all the great posts and info.

 

Don

Rear View Cell Mount_thumb.jpg

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  • 3 months later...

suppose i should read SCCA regulations, but i've recently toyed with the idea of autocrossing one of the Z cars. just got one from some old man for $150 and the only thing wrong with it is the driver's side frame rail , two itty bitty rust spots on the passenger side, and the gas tank. bought an aluminum RCI 15 gallon fuel cell/ with SU for $140 with work discount and have welded a cradle for it in the car already. take a look at these pics and if someone knows whether or not it's SCCA approved, feel free to reply and tell me i'm good to bolt it on and roll or that i'm an idiot and i need to cut it out and start over. please and thank you.

 

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It is the cell itself that has to be approved. I think only Fuel Safe and ATI make approved cells, not absolutely sure on that though. Your welding looks a little rough, but I don't think that strength is much of an issue here. 15 gallons of gas weighs ~100 lbs, so it's not the most heavily stressed area of the car.

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So I'm in the process of trying to figure out what I can to for my fuel cell. I picked up one of the 15gallon aluminum ones from Summit that arrived today.

 

Now the decision of how to mount it, whatever I do I'm going to have build a "metal bulkhead" to seperate it from the passenger compartment. Anyone have any thoughts?

 

This is an XP autocross car now, I dumped the idea of trying to make it SM2 legal.

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I used the same cell with ears welded to it and a cradle - foam filled. For the top I had a sheet of heavy duty sheet metal sealed with caulkRTV and pop riveted on top to cover it. Where the filler is I have a sort of square box that has a lid on it latched with a Dzuse (sp?) fastener.

 

the biggest issue I have is with venting. If I simply run an open hose off the top to outside the car I can evap gallons of gas pretty danged quickly. If I seal the tank it will SWELL bigtime! I have also had some teeny pinhole leaks in the RCI cell so beware of this, I fixed mine with small amounts of gas tank epoxy. Solving the evap issue is one thing I REALLy wish I could figure out as cracking open the garage and being greeted with gas fumes is NOT cool!

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You could put a pressure release valve on the vent. Then it will only vent after reaching a certain pressure..

 

Sounds like an excellnt idea, any ideas as to where to find one that can handle gas fumes? How do the OEMs do it? I've been tempted to find the stock vapor tank and try to incorporate it but I know that there were always lots of complaints about fumes in the cabin which I'd like to avoid...

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You don't want a pressure release on the tank vent. It would not equalize the vacuum in the cell so the pump would work harder and harder as the fuel level went down and the vacuum in the tank increased.

 

Most pumps are good upto 18 volts.. 14 for extended periods of time, and 12 for regular application. I'd imagine that the 2 volts increase to 14 would be more of a problem over an extended period of time than the tank vacuum.

 

but maybe it's just my brain spinning in circles.

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Come to think of it, I also had this issue when I tried sealing the tank - eventually the pump couldn't overcome it. There has to be a way to do this and I cannot be the first to encounter this.

 

As for pump voltage, I'm *not* a proponent of overvolting pumps. For one when you overvolt you lose amperage capacity - there's no free lunch. Walbro makes some good EFI pumps both internal and external although my 240 is carb'ed right now. My Supra ran dual HP Walbro pumps to over 700RWHP, I knew guys running triples, there were zero fueling issues even at 34PSI of positive pressure :)

 

FWIW, the Supra pump ain't so hot although I know many like it - you're better off with dual Walbro as the Supra pump sux massive amps. Dual Walbro suck less thana single Supra pump...

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How about venting the tank to the intake?

 

From a loss standpoint I'm not sure that would be any better when it sits in the hot garage but yeah at least it would be burned off while driving. I think the OEMs do that through a charcoal cannister and in the old Zs they did it to a tank in the right rear quarter where it could condense and go back - hence the fumes. Frustrating problem...

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^^^^^ The carbon canister and it's vent/purge system is exactly what you need to keep fumes down in the garage and vent the tank to the intake. It allows the intake to purge the canister without drawing a vacume on the tank. It also allows the vapors to vent and be captured by the carbon canister while the car sits in your garage. The canister is purged and reactivated while you drive the car.

 

 

 

 

 

The bladder-in-canister tanks are the safest. The rest are replacements for factory style tanks that offer no safety benefits.

 

You should provide a cover for ANY tank that would actually keep fuel from spraying the cockpit if it burst. Consider the fact that the cover will likely BEND in the event of a crash... Is it likely that your cover design will actually keep fuel out of your compartment in a crash???...

 

You should route high pressure lines OUTSIDE the passenger compartment. The vent and fill tubes are required to have IN TANK check valves to prevent them from spilling fuel in the event the lines are severed or pulled apart. The real hazard is in the pressure feed from the fuel pump... If that line is severed and the pump continues to run it will certainly spray the interior with fuel unless it is routed UNDER the car and away from the cockpit. I would seriously consider mounting the pump and the pressure line under the car.

 

If you are using a remote filler tube, then you need a seconday "fill vent". this is a large tube(>1/2") that is routed from the top of the tank to atmosphere. It is usually routed to the exterior filler neck to allow any overfill to wash back into the filler tube.

 

The fuel tank should be grounded to the chassis in multiple locations.... canister, top fill plate, and remote filler neck.

 

Many of the high end bladder style tanks have internal sumps with trap doors and dual internal pumps. Foam blocks are used to reduce explosion hazards both on track and in the pits/shop.

 

 

Here are some pics of my tank which is very similar to JM's design.

 

fuelcellstrapfittingrear.jpg

 

fuelcellstrapfittingtop.jpg

 

fuelcellstrapfittingbottom.jpg

 

 

 

 

 

 

tank internals: "Fuel Safe" Vortec-ASA fuel cell.

 

v8fuelcell.jpg

 

v8fuelcellsump1.jpg

 

v8fuelcellregulator.jpg

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