fuel tank - what would you do.

[fisha]

I'm now at the beginning of the rebuilt stage of the RR after replacing a rear inner wing but am wondering what to do with the petrol tank.

For most of the time ( in fact all of the time ) i run on LPG - even from start up - but i have kept the petrol + carbs as a backup in case i run out of LPG and need to get somewhere ( it has happened as i have to travel a fair distance to get LPG ) In the future, I may swap to EFI, but even then I would probably keep the petrol function if possible.

I have taken the petrol tank out in order to do the wing, but as it leaks, it is not worth salvaging or putting back in.

Should i replace the whole tank with another standard RR one / disco one....

Should i try and make / get made a smaller specialised tank that only holds a few gallons as thats all i need?

Should i fit the smaller tank which would allow me some space to T the exhaust pipe, make it run over the cip section of the chassis legs and then out on the other side. a set of twin exits !!!!!

so it would look like this ( existing one photoshopped by the way )

[geoffbeaumont]

Or how about small petrol tank + an extra underslung LPG tank so you're less likely to run out in the first place?

[LR90]

so it would look like this ( existing one photoshopped by the way )

That would get my vote. I can almost hear it from here

[Niall_CSK]

Looks a bit too X5 Rap artiste for my personal tastes, you asked

What is the point of making a long pipe all the way across the back when it would create so much back pressure compared to original side, especially when it's intended to be off roaded regullarly, you need to do at least a 50mm body lift to get it over the chassis and under it will likely get ripped off in the first 5 mins, you didn't ask for that but I have said it anyway If you are going for bling don't bother with the cross over pipe.

On the fuel side I might suggest a shperoidal (for want of a better description) tank (80 L) and a wing mounted petrol tank (about 35 L). OK so this just happens to be the arrangement I am using so I naturally think it's a good idea

I could lend you my wing tank as a pattern if you like.

[MarkieB]

I think I've seen those called toroidal as well, it must translate quite literally as 'doughnut shape', the options being 'ring doughnut' / 'jam doughnut' :D :D

[Dunc]

That would get my vote. I can almost hear it from here

Hang on, yes... "Blub blub blub lub lub lub lub lub lub lub lub lub lub lub lub"

Got it too!

Why not put 2 LPG tanks where the fuel tank used to be and then have a new (small) fuel tank up inside the rear wing? Maintain more clearance.

[fisha]

Niall,

would not having enough back pressure contribute to running lean? I slightly suspect that the current exhaust doesn't have enough back pressure, but how do you find out?

Boy racer rap gansta ( says you with your large bore exhaust tucked under the CSK pretending it aint there ) . . . . normally you hear the sub woofer before you see them. With this, you hear the engine before you see me.

When i said existing one photoshopped . . . all i did was clone the left hand side over to the right in photoshop. I already have the the gansta exhaust bling. I just want to double bling it !

in terms of tank / exhaust. The existing 90l tank is going to sit across the way where the rear seats used to sit - which will give me much more load room in the boot. I'm reasonably happy with the range from it. What i'm looking for in terms of a second tank ( petrol or LPG ) is that backup ability of being able to run to the next station to re-fill incase for what ever reason the main tank runs out.

I already have a 1" body lift, and if i dont make the tank too big, then the cross piece would fit easily over the dipped rear section.

[pugwash]

I've got a good condition metal fuel tank in the garage if you are interested?

[Niall_CSK]

Yes OK I do have it like that but it is very discreet & subdued untill you floor it, I just don't see the point of the 4 farters myself yours looks fine as it is. It has been known that reduced back pressure can affect mixture with carbs, shouldn't make a difference with LPG if you are using closed loop though.

I thought you were looking at doing away with the inside tank to get the extra space. I have a steel O/S long range wing tank that you can use as a template, it's about 35 L by rough estimate. Wouldn't take much modification to make it the only petrol tank. Take it yours is a low level filler. It sits in the space very neatly bolted to the body and doesn't affect departure angle at all.

Another option would be to fit a second 40 L LPG tank and cut your exitsing steel tank in half, problems doing that are having to muck around with the mounts, filler and sender whichever way you do it.

Plastic tank might be an option but you might as well get yours welded while it's out rather than go to the extra expense of modifying the fuel piping and the mounts.

[fisha]

the twin exhaust is not really likely to happen ( but it would be nice )

as for second tank, my current thought is for a cut down petrol one and leave the existing LPG tank sitting where the rear seats normally would.

i really dont want a full size tank as i wont be using its capacity. it also hordes the dirt behind it helping rust.

i figured that if i added a couple of right angled brackets on the inner sides of the chassis rails i could hang a short tank between them. so roughly the same width as a normal tank, but about 8" long from front to back and about the same depth as a normal RRC tank.

that should give me a few gallons which would be enough. and it should also mean easy access to avoid trapping mud and moisture like a normal tank does.

[geoffbeaumont]

It sits in the space very neatly bolted to the body and doesn't affect departure angle at all.

Did you make it yourself or buy it? Sounds considerably better than my wing tank, which while otherwise very tidy definitely does affect departure angle. I've already pranged it a couple of times (fortunately theres enough give in the brackets to protect it from light knocks).

[Niall_CSK]

Did you make it yourself or buy it? Sounds considerably better than my wing tank, which while otherwise very tidy definitely does affect departure angle. I've already pranged it a couple of times (fortunately theres enough give in the brackets to protect it from light knocks).

Several years ago I bought a long range wing tank in mild steel but the supplier was out of business when I tried to get hold of him later. It is designed to sit between the wing panel and the chassis on an earlier low filler. It is fitted by bolting along the forward upper edge to the lip created at the after end of the wheel arch and the floor. At the after end it is bolted to the lip created by the fold in the goal post lower crossmember. The mud flap & bracket are removed and the wing lower edge is bolted to a small tag on the side of the tank. In addition there are two brackets on the inboard side that rest on the chassis, hope that all makes sense. The filler hose is cut and attached to an inlet & outlet spigot, so it fills then overflows to the main tank.

The leading edge follows the curve of the wheel arch and the bottom surface is angled slightly to follow a string line between the wing lower edge and the chassis so there is no difference with clearance or departure angles compared to one without it. In fact it could be argued that there is less chance of damaging the wing & quater edges as the tank will slide over obstacles rather than catch. The mud flap is bolted to a bracket welded to the bottom of the tank.

The mild steel tank was a bit basic and I wanted a SUS one, then LPG came along, so I did a bit of redesigning and had several discussions with that lovely gentleman and wizard sheet metal & TIG welding guru Andrew Morris of Hilton in Derbyshire.

Using the MS tank as a pattern he fabricated a single tank that would take the original sender / pump assy. and fit a later high level filler unit with some modification of the filler pipes.

It is a work of art, I would rather sit and look at it than fit it. I dare say he could still make another, he may still have a screw neck that he had to have made especially, and even if he doesn't have the patterns I could always lend it to him for a few days.

Thousand words - now two pics

Sorry Donald, not intending to hijack your thread.

[fisha]

Niall

no problem . . . . it all helps actually to get ideas of what and what not to make a tank from - plus the idea of the ribs on the side of the tank

[Niall_CSK]

Not that long ago I gave away a square SUS tank that had been made for a special, that would have been quite easy to modify but I can't even remember who I gave it to now.

They are creases in the sheet, can't remember what the machine is called, stiffens and stops vibration, you will also need to consider internal baffles if you are making a custom one.

Just a thought, if you could put a transverse silencer behind it (with suitable shield) and then pea shooters both sides from that. More food for thought.

[fisha]

Just a thought, if you could put a transverse silencer behind it (with suitable shield) and then pea shooters both sides from that. More food for thought.

do you mean proper side exits rather than out the back?

now that would be cool

[Dunc]

do you mean proper side exits rather than out the back?

now that would be cool

What about Lakester pipes with a slashcut incorporated into a jackable sills?

[geoffg]

Fisha

I've made an ally tank for my tomcat, if you can produce a drawing of what you are after i'll see what i can come up with. Mine is 3mm ally plate as its nice and strong and it's easier to weld 3mm stuff.

cheers

Geoff

[fisha]

Geoff,

ok - i'll draught a drawing up over the next few days.

out of curiosity, what sort of setup did you use for pickup, return, filler and guage sender? so i can factor them into the equation?

Thanks.

[Niall_CSK]

do you mean proper side exits rather than out the back?

now that would be cool

Actually I was referring to your previous pics with 4 out the back but side exists would have the advantage of being less prone to damage now that I think about it.

What about Lakester pipes with a slashcut incorporated into a jackable sills?

Never heard that expresion before but that is what I had intended for my own project for the sake of protection.

[Dunc]

Never heard that expresion before but that is what I had intended for my own project for the sake of protection.

Lakester pipes are the exhausts that either run out of the bonnet and then down the side of the car, a la Cobra or down the side but concealed like this Mustang.

I reckon with those incorporated into jackable sills it would look the absolute dogs!

Could just be me getting carried away mind

[fisha]

would need too much heat sheilding i reckon. plus crossing under the chassis rails will seriously affect the ground clearance anywhere bewteen the axles.

all that being said. I love the idea of lakester style pipes just behind the rear tyres though - that would be really doable

[Niall_CSK]

Lakester pipes are the exhausts that either run out of the bonnet and then down the side of the car, a la Cobra or down the side but concealed like this Mustang.

I reckon with those incorporated into jackable sills it would look the absolute dogs!

Could just be me getting carried away mind

Right, with you now, something like this.

I think I will skip putting them out the side of the jackable sills, be just like someone to come along and stick a Hi-Lift into your lovely exhaust pipes

You could feed them down the sides independantly like the above just before the firewall.

That does open up a few other interesting possibilities.

Donald, you have already put a body lift on it so the cross over shouldn't be a problem as you have already pointed out, and it can't need any more heat sheilding than you have already.

I rekon put a split just after the Y piece over each chassis rail and a back box only under each side with the requisite ends. Then an LPG feed with Nova / Corsa igniter would have the desired effect, want to experiment with the gas axe

Edited November 15, 2005 by Niall_CSK

[Dunc]

Right, with you now, something like this.

Exactly!

With the problem of someone putting a high lift into the exhaust, why not build it so that the high-lift point is the exhaust.

I'm getting unneccesarily excited now!

[fisha]

I dont think i've quite got the space even with the body lift - i double check, but i still think its too tight.

i still think that if i go for the small fuel tank ( which i think i may well do ) then i definitely have the space to run the pipes overs the chassis at the rear.

which would mean I would be able to make side exits on each side just behind the rear wheels.

I dont see there being a problem with this provided i keep the exits within the departure angle line of the rear wheel to rear corner.

oh i think this may be a goer later on down the line

[fisha]

on a slightly related update. my definitive plan is to cut the rear floor in half. so i'll have a floor that splits across the way just where the wheel arch wells come back down to the floor at the back.

the front section will be riveted / bolted down to the support braces as per normal and will have the LPG tank sitting on it.

the rear half i will make removable so i can get into the top of the fuel tank and the general space around the rear.