V8 lpg

Ok so I got and had for 2 years+ now a V8 3.9 EFI Discovery 1, have just spent 500 notes on doing the heads and some other bits and peices, its already got the straight through centre box but I want to do De-cat the front pipes that are nearly shot anyway, they are blowing and quite weak one side under the flange so I was wondering if its possible to get V8 front pipes for the disco (Later version on chasis number) with out cats in? if so where or how much?
Any ideas greatly received

sidzf1 said:

Ok so I got and had for 2 years+ now a V8 3.9 EFI Discovery 1, have just spent 500 notes on doing the heads .

I was wondering if its possible to get V8 front pipes for the disco (Later version on chasis number) with out cats in? if so where or how much?
Any ideas greatly received

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I just spent the weekend doing the heads on my 3.9RRC, cost me my time but only £30.00.

Would have thought you could de-cat the exhaust but you will have to think about hat you will do with the sensors. You could try fitting downpipes from an earlier Range Rover but be aware some fettling may be needed because the Y pipes have slightly different dimensions depending on whether it is cat or non-cat, manual or auto so you will probably need the downpipes and Y pipe as well, then there is the risk your centre box replacement pipe won't fit. Strange coincidence I just fitted a centre box replacement pipe too.

Hi all.

I had my cats cut out and replacement pipe fitted just after the mot as one fell apart and was rattleing, then ran it (p38)for awhile until i plucked up courage to buy the new section and then fitted them for the mot having first head the section made into two pieces to get around the gearbox crosmember and then just used the cats for the mot as it was running on gas the rest of the time. Sounded much nicer and ran a little easier i thought.

Cheers, Nick.

if its lpg i believe you can mot it on lpg, dunno if the emmisions are better, they should be, might be worth asking at the mot station. as for the cats, i would cut them out and make up the space with some suitable pipe. most exhaust places will let you rumage through thier scrap pile if you ask nicely or bung em a tenner. once you have the pieces just weld it all up. or you could spend loads on de catting and have to put cats on for mot(dont really know if they should or shouldnt be on for mot)

lamda sensors - just get some nuts of the correct size etc and weld em on exhaust, drill hole in exhaust firs tho! or here


rimmers have em here at that price tho i would buy a mig welder!!!!

good luck!

my understanding of the MOT & LPG is that if it arrives on gas they have to test it on gas.

Not sure what that means for the requirement of a cat, not sure if it's doing anything with LPG, I'm assuming the components of the exhaust gasses will be different on lpg & therefore the cat may well be doing nothing

When i run on lpg its ace...
No cat required as im old but emissions are fine.Also you need very little compression to run on gas

Got stainless on my Lpg direct ,manifolds and Cat went no problem but the whole system cost at garage nearly 1000.Had to lift engine to fit. You do not need a Cat on Lpg and will Mot no problem.Gastronics fitted it in Bewdley he could probably give you more details have his number if you need more info on make.

lift engine to fit an eggsauce....

someone went for a fry up and charged you labor for it i reckon...

Dont forget you will still need your Lambda sensors fitted so the ECU gets the signal from them to keep the fuel mixture right. This applies to when you are running on petrol and (depending on whether your LPG system bypasses the Lambda sensors) it will apply when running on gas too.
Buy a servicable downpipe set including cats off eBay cheap, cut out the cats and weld in a suitable length of pipe on each side to replace them making sure you still have the holes for the Lamda sensors to be used.
If your current downpipe set is serviceable and its only the cats that are shot, why not try it with what you have now?

and let us know how you get on cos i want to do the same thing on mine...once I have the heads back on..

Island 4x4 do cat replacement pipes for £70 inc VAT delivered to your door. I'm about to do mine as the manifold flanges are dropping apart and checked with my MoT tester mate who said provided the car is registered before 1st Aug 95 there's no legal requirement if running on petrol. If emmissions are high put a resistor in the fuel pump power supply to drop the pressure slightly, that's what we do with the bro-in-laws jap drifter!