turbogrill Posted February 4, 2021 Report Share Posted February 4, 2021 Hi, Is putting the fuel cell in the passenger seat a bad idea? I have seen some people do it here but not sure if it's a very chumpy way of doing this or a good way. Do "real" race car do it? I would do it properly with having someone fabricate proper mounts and whatever shielding is needed. How do you do with the fill tube? Safety would be my #1 concern, being mega tboned with a fuel cell next to you doesn't sound great. thanks Quote Link to comment Share on other sites More sharing options...
mender Posted February 4, 2021 Report Share Posted February 4, 2021 (edited) My "real" race car do it. 100% Chumpcar legal and approved in 2013. The filler and vent tubes are now required to be enclosed. Safety was my #1 concern as well, NASCAR bars, plated between the bars, cell support structure tied into the cage, etc, just in case things go sideways (literally) and someone who didn't want to get passed (1:25) drives 100 feet deeper than normal into the corner after me then gets target fixation. Go to 1:45 for the result: Hit on the rear of the door bars that you see in the second picture, no damage to the cage but ripped the right rear suspension off and gave me grade 2 whiplash from the impact. And no, it wasn't fun getting hit, but repaired the car that night and was out for my stint the next day. Pretty sore on the 15 hour drive home. Not sure I as a driver would survive an impact hard enough to compromise the fuel cell structure that I built and certainly don't want to find out! Edited February 4, 2021 by mender Quote Link to comment Share on other sites More sharing options...
turbogrill Posted February 4, 2021 Author Report Share Posted February 4, 2021 How do you tackle the "fuelcell needs to be enclosed"? Lots of sheet metal? Quote Link to comment Share on other sites More sharing options...
mender Posted February 4, 2021 Report Share Posted February 4, 2021 (edited) As you can see in the first picture, the lower part of my cell has been enclosed so it's just the upper part that needs the extra that Champcar now requires. I have a remote filler that goes outside the car so I could fuel while doing a driver change that would need enclosing but a direct fill with just a top cover would be simpler to do. Edited February 4, 2021 by mender Quote Link to comment Share on other sites More sharing options...
turbogrill Posted February 4, 2021 Author Report Share Posted February 4, 2021 16 minutes ago, mender said: As you can see in the first picture, the lower part of my cell has been enclosed so it's just the upper part that needs the extra that Champcar now requires. I have a remote filler that goes outside the car so I could fuel while doing a driver change that would need enclosing but a direct fill with just a top cover would be simpler to do. The direct fill requires open the door. I can 100% promise that the door opening mechanism will fail when we are about to podium and turn our pitstop into a 10min ordeal so why isn't everyone doing this? Much better than having it in the trunk? Quote Link to comment Share on other sites More sharing options...
mender Posted February 4, 2021 Report Share Posted February 4, 2021 1 minute ago, turbogrill said: The direct fill requires open the door. I can 100% promise that the door opening mechanism will fail when we are about to podium and turn our pitstop into a 10min ordeal so why isn't everyone doing this? Much better than having it in the trunk? More work involved plus some have a phobia about sitting beside (as opposed to in front of) the fuel cell. The balance of the car doesn't change as fuel burns off when the tank is near the centre of gravity of the car. Quote Link to comment Share on other sites More sharing options...
mhr650 Posted February 4, 2021 Report Share Posted February 4, 2021 (edited) If I build another car this is how I am doing the fuel cell. Lots of advantages, weight of the cell, pumps and plumbing, plus the fuel weight when full offsets driver weight. Centralizes mass and makes plumbing runs for fuel plumbing much shorter. On overlooked advantage if you have a car that came with a rear mounted fuel tank is that once you move the fuel tank out you have the whole back of the car from the axle centerline to the bumper for aero purposes…. Good door bars, good cage around the cell, everything enclosed in sheet metal. Another nice thing is that you can mount your surge tank, pumps, regulator and any other fuel paraphernalia in the box that you built, make it all self-contained. I will install the fuel filler in the B pillar or rear quarter window, I really like to get the fuel filler up nice and high for easy filling, but then I always do the fueling and I am 6’3”. Edit: I would also make sure I put a fire system nozzle in the box just in case. Edited February 4, 2021 by mhr650 3 Quote Link to comment Share on other sites More sharing options...
turbogrill Posted February 5, 2021 Author Report Share Posted February 5, 2021 21 hours ago, mender said: More work involved plus some have a phobia about sitting beside (as opposed to in front of) the fuel cell. The balance of the car doesn't change as fuel burns off when the tank is near the centre of gravity of the car. So you would weld the cradle to the cage and then put a box around that. Or would the box be welded to the cage? 21 hours ago, mhr650 said: If I build another car this is how I am doing the fuel cell. Lots of advantages, weight of the cell, pumps and plumbing, plus the fuel weight when full offsets driver weight. Centralizes mass and makes plumbing runs for fuel plumbing much shorter. On overlooked advantage if you have a car that came with a rear mounted fuel tank is that once you move the fuel tank out you have the whole back of the car from the axle centerline to the bumper for aero purposes…. Good door bars, good cage around the cell, everything enclosed in sheet metal. Another nice thing is that you can mount your surge tank, pumps, regulator and any other fuel paraphernalia in the box that you built, make it all self-contained. I will install the fuel filler in the B pillar or rear quarter window, I really like to get the fuel filler up nice and high for easy filling, but then I always do the fueling and I am 6’3”. Edit: I would also make sure I put a fire system nozzle in the box just in case. What do you mean with the rest and aero? Remove the tank for a splitter instead? The surge and stuff will be in the box but not so protected right? Quote Link to comment Share on other sites More sharing options...
mhr650 Posted February 5, 2021 Report Share Posted February 5, 2021 Underbody aero is way more efficient in terms of lift/drag than wings. With nothing behind the rear axle and ChampCar liberal aero rules you can make something really nice. http://speedhunters-wp-production.s3.amazonaws.com/wp-content/uploads/2013/10/24160032/WTAC-Aero-32-1200x800.jpg If you make a cage from 1-inch square tubing and cover it with sheet steel I would think anything inside would be at least if not more protected as having them behind the driver in the trunk or hatch. I would mount the pumps and surge in front of the cell where the passenger’s feet would normally go, this is a really strong part of the car with the A pillars and door mounts. As for tying the fuel cell cage into the door bars like Mender did, I would have to think about that, to me I could make a case for or against. Obviously it is strong to tie stuff together, but if you connected the fuel cell cage to the main hoop and A pillar bars, and then ran your door bars outboard it would allow some inches of deflection of the door bars before they would effect the fuel cell cage. One of those things that deserves lots of thought to get it right. Quote Link to comment Share on other sites More sharing options...
mender Posted February 5, 2021 Report Share Posted February 5, 2021 6 hours ago, mhr650 said: Underbody aero is way more efficient in terms of lift/drag than wings. With nothing behind the rear axle and ChampCar liberal aero rules you can make something really nice. http://speedhunters-wp-production.s3.amazonaws.com/wp-content/uploads/2013/10/24160032/WTAC-Aero-32-1200x800.jpg If you make a cage from 1-inch square tubing and cover it with sheet steel I would think anything inside would be at least if not more protected as having them behind the driver in the trunk or hatch. I would mount the pumps and surge in front of the cell where the passenger’s feet would normally go, this is a really strong part of the car with the A pillars and door mounts. As for tying the fuel cell cage into the door bars like Mender did, I would have to think about that, to me I could make a case for or against. Obviously it is strong to tie stuff together, but if you connected the fuel cell cage to the main hoop and A pillar bars, and then ran your door bars outboard it would allow some inches of deflection of the door bars before they would effect the fuel cell cage. One of those things that deserves lots of thought to get it right. I went through the same process with my car (Fiero) but decided to have the cell against the centre console. It can move up to a foot before getting to the driver's seat so lots of crush available. It would be a pretty hard hit to move that far with my door bars and such. 1 Quote Link to comment Share on other sites More sharing options...
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