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So I’m in the process of installing a fuel cell in my Cobalt.  The stock tank is plastic and located ahead of the rear axle (beam).  It’s very low.  Current f/r spilt is 65(f) and 35(r).  
 

The car is pretty decently balanced as it sits.  Slight bit of oversteer when trail braking. Stock rear camber is basically zero.  
 

Im very new to a fwd car.  I can install the fuel cell either in front of the axle or behind.  Behind is easier from a fabrication standpoint, and an exhaust routing standpoint, but would increase rear weight percentage.  
 

Which way should I go?

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1 hour ago, petawawarace said:

So I’m in the process of installing a fuel cell in my Cobalt.  The stock tank is plastic and located ahead of the rear axle (beam).  It’s very low.  Current f/r spilt is 65(f) and 35(r).  
 

The car is pretty decently balanced as it sits.  Slight bit of oversteer when trail braking. Stock rear camber is basically zero.  
 

Im very new to a fwd car.  I can install the fuel cell either in front of the axle or behind.  Behind is easier from a fabrication standpoint, and an exhaust routing standpoint, but would increase rear weight percentage.  
 

Which way should I go?

A big consideration is the metal bulkhead that has to separate the fuel cell from the driver compartment. It's pretty easy if the cell is in a stock trunk area. Difficult if it's around the back seat area (unless it's fully underneath the back seat sheet metal).

 

I try to err on the side of simplicity and ease of fabrication. And ease of servicing. 

 

I also hear some FWD guys gripe about how much front weight they have. Too much front weight is a bad thing, but how much is too much? I haven't the answer to that.

 

I would put it in the back.

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It would be easier to put further back. But I’m decent with the fab side of things so either one is not a big issue.  
The weight distribution question is the one I’m not sure about.  If this was a RWD car, get that weight back as far as possible.  FWD is a different beast. 

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Ive read articles that say 60-40 for a FWD is a good target to shoot for. Ive never built or set up a FWD car myslef just relaying what ive read.

 

If it were my car and i can keep  the cell safe in the back id put it there to gain distance from cell to driver. Good Luck!

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We have a Chevy Beretta and have just installed a new fuel cell in a kind if new location. Like your car the stock tank was low and in front of the rear axle. When we first installed our fuel cell we went in the truck space basically where the spare tire resided. It ended up being a little too far back and a bit to high. It really changed the way back end of the car behaved in corners. For this season we went with a cell that is longer and shallower. We located it as far forward in the truck space as possible without having to alter our already completely sealed fire wall. We also mounted it as low was we could manage without interfering with the rear suspension beam. Handling is much better. It was a bit more work to squeeze it in there but worth it. 
Ideally we would have planned on a cell when the car was first built 7 years ago and placed it in the rear floor of the passenger compartment but it isn’t very feasible now with the car as it sits. 
Not sure if you ever run into the CRX that is campaigned by 90Racing and Andrew (Red0 on the forum). It has a nicely placed cell right in the rear floor area and if I remember correctly the steel cell surround is welded into the chassis.

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7 minutes ago, Kentite said:


Not sure if you ever run into the CRX that is campaigned by 90Racing and Andrew (Red0 on the forum). It has a nicely placed cell right in the rear floor area and if I remember correctly the steel cell surround is welded into the chassis.

It is a fantastic cell location for weight balance. And a great location for crash safety as it is well within the roll cage. And the way it is welded into the car is great. But building the bulkhead to shield it from the driver compartment (mandatory) was a nightmare for them. Now, hatchbacks are going to be tough when it comes to a cell bulkhead in general, but as far forward as it was made it worse. They have dozens of pounds of sheet metal into that bulkhead and getting it apart to do service on the cell / pumps is no fun. Remember, you have to shield the filler neck, too. 

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I guess I haven’t seen it since they’ve had to shield it. I can see how it would have been a nightmare. Dozens of pounds of sheet metal sounds horrendous. Ours was relatively simple to build a bulkhead wall and fill the gaps with fire foam. Easy access to pumps, wiring and lines. 

Edited by Kentite
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We ended up mounting ours between the rear strut tower right above the rear sub-frame.  This required removing the metal that separates the back seat from the trunk.  We did this before all the new fuel cell rules came out but we still managed to enclose everything in metal including all lines and hoses.   We weight distribution front to rear is very close to 50/50 with a full tank and driver.  

Pizza%20Oven%201_zpsuteiwzuh.jpg

 

 

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49 minutes ago, hcsi99 said:

We ended up mounting ours between the rear strut tower right above the rear sub-frame.  This required removing the metal that separates the back seat from the trunk.  We did this before all the new fuel cell rules came out but we still managed to enclose everything in metal including all lines and hoses.   We weight distribution front to rear is very close to 50/50 with a full tank and driver.  

Pizza%20Oven%201_zpsuteiwzuh.jpg

 

 

 

Going to be fun to watch this car at road america. Such a clean build.

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Debating this for the Mini as well. 1st thought was to remove the factory tank, cut out the floor, and weld up a frame to support the cell. Keeps it in the stock location and protected.

Edited by mindspin311
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On 7/9/2020 at 12:20 PM, hcsi99 said:

We ended up mounting ours between the rear strut tower right above the rear sub-frame.  This required removing the metal that separates the back seat from the trunk.  We did this before all the new fuel cell rules came out but we still managed to enclose everything in metal including all lines and hoses.   We weight distribution front to rear is very close to 50/50 with a full tank and driver.  

Pizza%20Oven%201_zpsuteiwzuh.jpg

 

How is this enclosure constructed? Is the lid of this cell box, that we can see here in the photo, exposed (single layer)?

 

Or is this a shoebox syle cell and you made your own secondary enclosure around the whole thing?

 

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