diesel de-catted - otter
I know this subject has been discussed quite a bit already, and its quite confusing with 1992 cars - does anyone know if its possible just to take off/destroy the cat on a 1992 K reg Golf III Turbo diesel (non TDI)?
Will it still pass MOT requirements if the engine remains well-serviced and smoke-free? Would bio-diesel help meet MOT diesel tests?
Will it improve power and economy?
diesel de-catted - Andrew-T
I think cats became a legal requirement for petrol engines at 92K, but not for diesels until several years later. Other things being equal, performance must improve because of reduced back-pressure, but would the chip need tweaking?
diesel de-catted - BrianW
My 96 P Pug 405 has a cat.
Apparently they are as rare as hens teeth.
When the exhaust blew a leak at the bottom of the downpipe the main dealer wanted £350 for a front section but (thank goodness) couldn't get hold of one for a couple of days.
Formula 1 hadn't any in stock either.
So I got it welded for about £40.
If and when it goes again I intend replacing it with the catless version.
Still learning (I hope)
diesel de-catted - Pete F
Diesel cats even on current cars only do a bit of oxidation to reduce HC and CO slightly. The engine management does not know if it is there or not, so removing it won't cause any problems. Cats on Diesels were incentivised in Germany before other countries, so VW tended to be the first with them. Ford used to fit them for certain territories only, depending on incentive/political reasons. MOT won't be affected. Performance/economy should improve slightly but why and how are you doing it?
diesel de-catted - andymc {P}
You asked about using biodiesel. All things being equal, it will mean lower emissions of CO2, CO and particulates, but show a slight increase in NOx (is this measured at MOT?). This can be brought back to normal levels by retarding injection timing by a couple of degrees, but if you don't plan to use biodiesel all/most of the time it's better to leave it as is.
diesel de-catted - otter
I was just interested so that if the mechanic doing the MOT phones up one day saying "your cats knackered, you need a new one" I can just say "no need, just replace it with a straight pipe thanks." And if it saves on fuel its proberbly helping save the environment anyway.
I was interested in biodiesel because a friend's giving me a Merc w124 250TD which are supposed to run well on veggie/diesel mixes. If it works I might try a bit in the golf, although at smaller amounts.
Anyone got any good info on the Merc W124's by the way? The autoboxes are supposed to be strong but do they have that self-levelling suspension?
diesel de-catted - andymc {P}
If you go to biodiesel.infopop.net and do a bit of searching, you'll find a number of people who've converted older Mercs to run on vegetable oil. They are the most popular cars for converting because the engines seem to be so suited to it. The most popular one of all for conversion seems to be the 300D, but yours should be fine. If you want to run on veggie oil only, you'll need to convert the car to a pre-heater and two tank system to allow for starting and stopping on derv/biodiesel before switching over to veggie oil, otherwise the veggie oil can gel in the fuel pump/injectors once it cools down. If you want to run straight biodiesel or a mix of veggie oil and derv, then you won't need to do any conversion. The Golf, if built after 1996, will be warrantied for use with pure biodiesel so you shouldn't have any problems there other than the possibility of a short term clogging of the fuel filter if it's done a lot of miles on derv. Once the gunk deposited by derv at the bottom of the fuel tank is cleaned out, the filter will no longer clog.


Value my car