Lying awake last night as you do I was contemplating different car designs.
Question - where do most people put the fuel tank in a mid engine car?
To me the obvious choice froma weight distribution point of view would be up front, but does this pose undue safety problems?
Yup.
Even under the rear seat ( most modern cars ) I have seen them go bang ( race car with full cage !!).
A GT40 replica I have seen had them in the Side Pods ! ! !
I think where ever you put it there is a chance. but leaking is one thing leaking ont somthing that will cause it to ignight is the main problem
regards
Agriv8
The tank sits up front in my Mojo- don't see why it is any more of a safety risk than the standard locost position out at the rear to be honest,
in fact if anything it is better protected by chassis rails up front:
Neil
quote:
Originally posted by Agriv8
...
A GT40 replica I have seen had them in the Side Pods ! ! !
...
Whilst at Palmers when I was working on Caterhams I was passengering in a car when we were involved in a crash. My guest had just spun and come to
rest facing the right way on the inside of the track. An unaccompanied guest in another Caterham saw us, panicked and promptly spun hitting us back to
back. This was quite a low speed collision but it was sufficient to bend the chassis on both cars and rupture the fuel tank on ours. My head hit the
unpadded rollcage and it hurt like I had no helmet on. This remember was with one car stationary and the other travelling at perhaps less than 20mph.
Fortunately there was no fire and we were all fine. The point I'm trying to make is there is no safe place for a fuel tank and in my opinion, at
the front is as safe a place as any other. I've put mine there on the trials car mainly because there was no room for it anywhere else!
John
This question gave me heart burn for some time...
Out the back too dodgy and wrong for weight
In the front no room and wrong for weight.
In the side pods. too scary.
Finally I settled for behind the seats, so its surrounded by steel tubes on most sides and me on the other. But thats not a perfect solution
either.
Being a long time motorcycle nut, in bike design for the last 15+ years now a lot of attentions gone into fuel tank placement because the weight and
movement of the fuel can effect the handling of the bike. This has lead to fuel tanks being concentrated at the C of G the bike so that the varying
fuel load doesn't stuff up the handling.
The effect will be smaller on a light car but much larger than that on the family saloon.
Which is a long winded way of saying I think somewhere in the middle is the best place to stick the thing.
Doug.
I put mine where the transmission would go in a traditional layout 7. That is, just forward of the shifter. That gives maximum crushable space in any
direction.
tank placement
The tank is completely sealed from the passenger compartment by paneling. Weight distribution is 41/59 with it here. Oh and I calculated that moving
the tank to behind the seats would only shift the CG by about 1".
How do they do it in the Ariel Atom?
[Edited on 11/22/06 by kb58]
Hi as doug68 says assuming that you are sat in the safest area of the car why put the tank any where else also assuming that it is behind a seald
baulkhead. As the term middy sugests putting most of the weight in the midle area of the layout.
cheers matt
My twin 25 ltr tanks are in the side pods, making it perfectly balanced while keeping the weight as low as possible. I have a balance pipe between the two but a single fuel pump in one.
most tanks i've seen on mid engine racecars (prototype sports cars mainly) have been behind the seat(s) or alongside the driver between the
engine firewall and the short of you back of the seat in a sort of vertical wedge shape.
They have all used fia approved bag tanks which are meant to be more resistant to damage/tearing/splitting in a situation where an ally tank would
normally burst.
Ned.
In the new Ford GT they put the fuel tank in the middle in the transmission tunnel.
It has been specially molded to accept the gear lever.
Mine is going out the front like porsche do, its surounded by the chassis so is well protected.
The best place for the tank is in the centre of the car especially if you plan a large tank.... but not always practical.
I placed mine (twin tanks) behind the seats in the McBearen.
Dick Bear
[Edited on 22/11/06 by Dick Bear]
Here is a photo I've tried to post of the twin tanks.
The fire wall had not been installed at the time the photo was taken.
[Edited on 22/11/06 by Dick Bear]
Rescued attachment McBearen_twin fuel tanks.jpg
The toyota MR2 series all had them in the fake transmission tunnel. mk1 has nice tank, maybe usable with a little modification.
anyway fill them with foam so they don't leak very hard, and don't crash!
grtz Thomas
Mine is transverse behind the seats and it's the original MR2 tank, but I cut about 10" off the end and welded a plate on so that it fit the space. Then I coated the inside with some plasticized liquid that's supposed to be impervious to everything. I bought the coating from eastwood.com. My newest design has twin tanks behind a firewall just like the McBearen. That's right on the CoG.
My car originally had a fuel tank placed in the front but the builder/ previous owner found it effected the handling alot as it was emptied during a
track events, and it was too small. So a larger one was added behind the passenger seat. However it has made the passager seat sits a bit to far
forward for my liking so one day I will make a new tank that will sit across both sides. As the tank behind the seats is closer to the CoG the change
in weight as you use the fuel has least effect on the handling of the cars. It is important to note new builds will need the tank to be seperated from
the cockpit.
It is worth looking at using a MGF ( plastic tank) or a lotus Elise tank) agian both of these are behind the seats.
I think this is the record for a thread resurection.......
Of course, it's all interesting, but the original post was 8 years ago :-)
Nowt wrong revisiting old threads.
I'll be using a MGF tank, fits nicely between the seats and the engine. It will be getting a double bulkhead.
quote:
Originally posted by Jenko
I think this is the record for a thread resurection.......
Of course, it's all interesting, but the original post was 8 years ago :-)
mine sits right at the back of the car inside the chasis on the global although when I eventually do my engine swap I will probally look into moving it and fitting a smaller one as the current one is way to large for my needs and has a couple of issues in its location i.e the exhaust goes right above it so its a bit of an arse to top up after the car has been run I know another ex global driver that relocated there tank to the side pod
My Ginetta G32 has it up front, then the spare wheel lays above it.
I remember an article about the Honda NSX and having it's fuel tank behind the seats, this was because they didn't want the handling to
change as much during a full or empty tank.
In my new design, Midlana, it's a triangular tank across the chassis behind the seats and ahead of the engine. Not really many other places to put it and it's completely wastes space otherwise.
The only two sensible places, IMO, are across behind the seats or in a traditional "transmission tunnel" location. Minimal GofG shifts with
fuel use, maximum impact protection from any angle. But I'd always have a fireproof, liquid penetration-proof bulkhead between tanks and
people.
Putting it up front to generate a better static weight distro can be a mistake as you'll end up with a massive,and variable, rotational inertia
affecting your yaw rates.
[Edited on 20/8/14 by coyoteboy]
Thread reserection again!
I,m now at that stage of redesigning the tank as, I cannot fit harness mounts without changing the tank, I currently have a Bosch 044 pump external
and gravity fed with a swirl pot on the bottom of hte old tank, this reduces the minimum lowest level of the tanks so I was thinking of fitting an in
tank pump and then using an external swirl pot with internal O44 mounting as that reduces space. However I not really found much universal in tank
pump systems that I can adapt and mount on a flange. Car builders have a setup but its quite low flow ( I may turbo my car in the future so want some
headroom) alot of the welbro in tank pumps flow well but are designed for retofit. Just wondered if anyone knew of any good mounting brackets. I plan
to make my own aluminium tank and weld it up to fit as needed.