Fuel Tank for Sprints n Hills

[a4gom]

1/ What sort of capacity is generally considered enough?

2/ Any issues with mounting them under the bonnet?

3/ Anyone got one they don't want?

[Bananaman]

1. Never sen anybody who has mounted one under the bonnet but can't see why not if there is enough room Apart from the obvious risk of fire!!!  

2. Mine was 10L jobbie from AH fabrications, top bit of kit and if you deal with them direct (do a google search) he will mod it for you RE mounting points, swirlpots, breathers/roll over valves, etc...

3. No sorry sold it a while back.

http://www.ahfabrications.com/  

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[Mark Stanton]

QUOTE

2/ Any issues with mounting them under the bonnet?

Fire more likely to start in engine bay      

Crash more likely to happen from front end .... seee above      

[peterg]

2 gallons or 10 litres should be enough, don't put it under the bonnet though as the risk of puncture from large components flying about in an accident is too high and the various sources of ignition only too obvious  

there needs to be a fireproof bulkhead between the driver/passenger compartment and the fuel tank and therefore just about everyone puts a small tank where the original tank normally goes above/behind the diff    

[John Loudon - Sponsorship Liaison]

If I had a BEC, I would be mounting it in a panelled off end of the passenger footwell like a dry sump tank with the cap sticking through the bulkhead under the bonnet

Oh - and it would be one of these   Light and cheap  

[Mark Stanton]

QUOTE

If I had a BEC, I would be mounting it in a panelled off end of the passenger footwell like a dry sump tank with the cap sticking through the bulkhead under the bonnet

Possibly o.k for non-road going class cars     but not for road-going where seat needs to be retained  

[Blatman]

Yeah but remember Johns rear mounted fuel tank is going to be at risk from unguided wheels. He probably is safer having his tank in the passenger compartment

Everyone else, probably not so much...

[John Loudon - Sponsorship Liaison]

It would be in the footwell so cant see anyone wanting to sit down there  

[Bananaman]

It would be in the footwell so cant see anyone wanting to sit down there  

I'd be OK for you short  types....

[a4gom]

End of footwell shouldn't be too much of an issue, seen plenty of cars with dry sump tank there and there still been enough leg room.

TBF only passengers my car sees are the kids anyway.

I've also seen plenty of cars with swirl pots under the bonnet so whats the difference? Surely a swirl pots worse as its receiving fuel under pressure so would spread further and faster if punctured.

My thoughts behind this were the fact I can't get rid of my understeer since changing from xflow to R1, the car just feels too light over the front end, results from corner weights show this with 42% of the weight at the front 58 at the rear. There isn't really anything else I can move, I only have a small battery in the footwell, moving that to the nose won't make much difference. So I was considering removing the standard tank and fitting a small tank at the front. This would shift quite a bit of weight as I run with the tank almost half full to combat surge at the moment.

I run the bike pump in my existing tank and thought a small tank in the front with the bike pump in would do the job. I was thinking less than 10 litres though. The standard R1 tank only holds 18!

I was thinking it would only be used in competition with the standard tank been put back in for the road.

[peterg]

Capacity depends what you use it for, if just for competition than 4-5 litres will be OK but if doing a track day you'll need more...

My 1100 bike engined single seater only had 6 litre tank and I used it roughly half full and then put 1 litre in it after two runs at places like Curborough and Shelsley and 1.5 litres after two runs at Loton and Pembrey.

[Kevin Jones]

When compared to my blade converted to R1 that is quite a difference, the split I have recorded was 48/52. It's not so clear to me though that you will cure understeer by moving weight around. More likely I think you need to change front/rear balance or look at how much roll vs camber you are running.

[pistonbroke]

Agree , and add that I would have thought more rear weight bias would promote oversteer  

[John Loudon - Sponsorship Liaison]

QUOTE

Agree , and add that I would have thought more rear weight bias would promote oversteer

surely you mean understeer

[a4gom]

Kev I'm not sure either that i will cure it but I had no significant problems with handling before the change and I haven't done anything else except add the cage.

The amount of roll I have been running has been commented on previously and I'm sure I would benifit from adding some anti roll bars, I have tried running with the shocks adjusted to make it stiffer but this has made the understeer worse.

I don't have any details of the weights before the change but I'm pretty sure the weight of the xflow engine would put the balance to the front.

Changing the tanks, even if i don't put the small one in the front ,will reduce the weight at the back and this is going to reduce the differnce in the split.

Car has 1 3/4 degrees negative camber on the front, 1 1/4 on the rear. 1mm of toe out on the front, 1mm to in at the rear and 25mm of rake.

I'm open to any suggestions as I'm a bit stalled with it all at the moment.