air filters

[idris]

I tried changing to K&N filters on a Rover 3.5 V8 with twin SU's and found that power was down on lpg, I think this was due to insufficient venturi effect from the free flowing filter.

Changing back to the old filter cures the problem, even running with the Y piece in place and connecting the flexible hose to just one K&N cures the problem.

It did sound nice on petrol on the K&N filters but I need to run mostly on LPG.

So what do most people use for an air filter in this situation?


Gerald

[webber1982]

running any type of hi flow air filters with gas isnt the best idea unless you are able to alter the fueling right through the rev range to compensate for the extra air then all u will achive will be to weaken the mixture and running on a lean mixture for too long can cause damage. i see loads of people who have fitted these type of filters because its backfired and blown the air box to bits if its backfiring theres a problem usually plugs and leads related. ive even known some installers actually recommend k&n style filters so when it backfires it does no damage, so when it backfires jesus do the job properly or just dont do it. if ur gonna run k&n,s then put it on a gas analyser and adjust the mixtures but im doubtful if ull be able to do it for out of idel revs with a carb set up.

[The Original Tom]

I have a huge cone air filter on each of my carbs, and the LPG performance is really shoddy.
I've heard of other people doing it a similar way to me though so I thought it would be ok.
I'm just trying to find somewhere that can supply the rquired 63mm ID flexible pipe without taking the p*** with the cost!
I also want to find a y-piece so I can run both carbs off 1 filter and eventually attach a snorkle...

I'd go back to the old airbox for LPG, unless you can afford £900 for an ECU gas injection system...