Thread: extra fuel tank

Hi, that crumple zone might alter when I mount a steel rear bar and two spare wheels back there.
Alan

Originally Posted by Scouse

One thing you might want to consider before mounting a fuel tank in the spare wheel well is that it's part of the rear crumple zone.
This was in the new model training back in 1994 & the spare wheel is also designed to be in the well to act as part of it.

A long range tank is available (last time I checked at least).

Originally Posted by old dirt bikes

Hi Prelude,
my motor is about the same as yours but I have fitted Hurricane headers and I got rid of the cats and fitted a straight through muffler and 3inch system from the Y join back, and 60mm pipes from the headers to the Y join. The big thing that holds the 4.6 back is it can't get rid of the exhaust gasses quick enough. The people that make the aftermarket cylinder heads have overcome the problem by making their heads about 1/2 an inch higher, a lot more port area. Also they moved their valves to the middle of the cylinders which allowed them to fit much larger valves.
The after market head people, I can't remember their name right now, dropped the price of their heads just after I had spent 2 months porting, polishing, triple cutting the valves and seats, checking and adjusting combustion chamber and port volumes and setting the seat pressures. At the new price I would had gladly paid the money for their heads. I also have a tornado chip fitted to my ECU. I am hoping to get a bit better fuel economy out of the 95 P38. I haven't done anything to the drive line yet, but I I do have a MaxiDrive locker rear end to fit in it soon. Yes I think that your camshaft would be starting to make good torque at just over 2,000 rpm. Which with 32'' tires you would need to be well over 80 kph. I think 120 kph it would be just in the bottom of the power band, 2 stroke terminology. Are you located in England? (MOT), none of that over here in Queensland Australia. I am trying to have my -/95 P38 going by the end of next week, so it won't be long and I will see how much fuel it uses and how well it goes on the road..
Regards,
Alan Temperley

Alan,

I know of one such head; the merlin stage 4 from RPI, the same guys that did my engine for me. I was tempted back then but at stage 3 the costs were high enough already I do have an aftermarket exhaust system but no cat delete (yet) I need to fab something that will fit in quickly since I would need to return it every year for the MOT. I do have an old Y piece laying around that has faulty CATS so I might simply modify that to suit. I would want to weld on some decent flanges since that slide over system is just not very user friendly. Also, iirc you need to remove the gearbox crossmember to get the exhaust in and out and that's more work...

Anyway, yes, the cam screams when pushed. The funny thing is with them modern eco-bangers, a 2.3tonne P38 can still beat them at the lights sure, what comes out of the tailpipe contains enough fuel for them to drive on for a week I guess but it is still fun!

I just went digging through my old pictures and I found the set I made to see what my road speed vs RPM was with the muddies on:

80kph is 1750 rpm
90kph is 2000 rpm
100kph is 2250 rpm

And no, I do not live in the UK but the term MOT is something most people understand so I use that, I live just across the pond in the Netherlands. Much more regulation, much less possible in terms of self built though we hardly get any rules that work backwards. So a new vehicle and a roo-bar is almost impossible down here, but if your vehicle is from before 2008 you can almost slap anything on it.

Lastly @scouse, I have been looking into that indeed. It is of some concern to me to at least make sure that it is as safe as can be, a reason to mount the fuel tank below the vehicle and not in the wheel well for sure. I do agree with Alan on this though, I pretty strong rear bar and in my case a bashplate that is mounted between the rear bar and the lower steel cross member that runs underneath the wheel well should create sufficient stiffness that there is no such thing as a crumple zone anymore. Most passenger cars will slide underneath (the bashplate wedges them down or me up) and if a truck would hit me that hard, we might have bigger problems than a fuel leak (and potential fire)...

I know of the long range fuel tank, I looked into them a couple of years back but they only offer 30 litres of extra fuel iirc and they do tend to stick out quite a bit lower, fouling up ground clearance. They are VERY well built though (brown davis I believe) but that also adds to weight.

Cheers,
-P

PS I stand corrected, the total fuel capacity would go up to 155 litres which is 65 more than standard I believe? if I round my fuel usage up to 20l/100 (tracks, sand, etc.) I would get around 775km of range. Still not the 1K I am aiming for but perhaps doable.

Hi Prelude,
I had a big day working on the Rangie today. I had a problem with the EAS, when I pumped up the tank it would leak all the air out of the exhaust port. So I changed the complete under bonnet unit for another one I had in the shed. Same problem, so I changed it for another one, same problem again. I was beginning to think the problem was else where in the vehicle. My last option was to take the EAS unit out of my -/96 Rangie that I drive every day and it rarely gives any trouble. So I swapped it out and bingo no more leak. Now I just need to find the problem and fix all 3 EAS units. I finished wiring in some aftermarket switches, and I am close to finishing fitment of some aftermarket gauges. All done without drilling any holes in the dash. A few little jobs to finish in the morning and then a wash and a polish and I can go for a drive. I still have to finish my bullbar and blast and paint the same colour as the vehicle. Then I will have somewhere to mount my spotlights, light bar and UHF aerial.
Regards,
Alan

Hi Prelude,
Wildcat were the cylinder heads I was thinking about. At least with our idea of a fuel tank mounted below a solid steel floor panel it would be similar to most other vehicles on the road. Unlike all the P38's out there with one of doughnut type LPG tanks in the spare wheel well. With the occupants protected by a piece of imitation wood. When I used to fit LPG to motor vehicles back in the 1980's, the tanks had to be fitted outside the vehicle cabin. Maybe the rules have changed these days. I got to go for a drive in my Rover today. Now my list of things to do to it is even longer. I did not get far, just down the road and the temp gauge was in the red. But the engine overheat alarm was only reading 84 degrees. So I stopped for a while and let it cool down and drove it home. I will order a new sender unit and then I will try it again.
Alan

Ah yes, wildcat

Anyway, it seems you have plenty to do still. That's what P38's do I guess. Most of them neglected. Nothing new since my gf's honda (and I am not used to honda's being that bad) clearly had some maintenance lacking, although not visible, and I have had to change or fix a damn christmas list of jobs

The doughnut type tanks are remarkable sturdy. I have no knowledge of them ever being crushed and explode. Anyway, I reckon that fitting the tank safely and making sure there are holes in the bottom perhaps so that a ruptured tank vents to the outside would suffice?

Cheers,
-p