MR2Mk1

iTrader: (1)

I have a year 2000 classic wagon and keep seeing posts about De-cat pipes.

How much if any difference would it make to a standard car with a prodrive back box?

I presume it only just makes it louder and would need to be retuned and replace with Cats for MOT?

Evo Son

de-cat pipes are designed to to derestrict the gasses exiting the turbo allowing faster "spool up" reducing initial turbo lag and improving throttle response in the lower revs.

In most cases yes you would need to replace it for the original cat at MOT time

bustaMOVEs

iTrader: (31)

^^^also with a remap.

Scooby B

iTrader: (2)

Better exhaust gasses = POWEEEEEEEEER!

chocolate_o_brian

iTrader: (22)

Powaaargh!

Next.

tubbytommy

iTrader: (20)

dont forget the odd flame pop out the back

MR2Mk1

iTrader: (1)

So basically if I fit a De-cat it will need re-map and not pass MOT so at MOT time I need to put original back on then Re-map again then re-map a 3rd time after I put de-cat back on after MOT. Sound like a lots of cost and faff.

So what if I put one of the Sport cat things on I presume that passes MOT and would give some benefit after a re-map and if so what are the recommended ones for a standard set up?

Infected by sti

iTrader: (6)

Shouldn't have to remap it back to run a cat just for mot, should pass easy enough even with a map, I'm sure others will correct me if I'm wrong!

Just swap cat over for mot an as soon as its done pull it back off, alternatively find a friendly garage thas willing to help

chocolate_o_brian

iTrader: (22)

Friendly MOT garage is the easiest option.

JDM_Stig

iTrader: (3)

or run a decat up pipe and sports cat downpipe, so you get the better spool from the decat up pipe, no bits breaking up and trashing your turbo if the up pipe cat breaks up, and the sports cat means you pass the mot`s.
hth

MattyB1983

iTrader: (51)

He won't have a cat in his up-pipe.

Decent exhaust with a sports cat downpipe, decent panel filter, new fuel pump and a remap will see a healthy power gain and will be all good come MOT time.

MR2Mk1

iTrader: (1)

So basically all i need is the sports cat downpipe going into the centre pipe with it's cat then into the Pro drive box on the rear so it still has the 2 Cats to pass MOT?

JDM_Stig

iTrader: (3)

only needs 1 cat for mot

MR2Mk1

iTrader: (1)

So i could just get Sports cat then de-cat centre section then re-map and that should give better performace and still pass MOT?

scooby-k

yes

RICK...

iTrader: (2)

Exactly what I have on mine and flies through MOT

MR2Mk1

iTrader: (1)

Would it also work the same regarding BHP and MOT if I used a de-cat down pipe and left the cat in the centre section. Only reason is it’s probably cheaper to buy a 2nd hand de-cat down pipe than getting sports cat and de-cat centre pipe?

Sorry for all the question but only used to N/A cars with no Cats in the past.

super_ted

iTrader: (30)

I have a bell mouthed sports cat down pipe, that way you can do away with the other cats, enjoy better gas flow & still be emissions legal - if you're interested pm me.

STEVEBOXER

My classic has centre decat and no re map. Mot man said as long as it passes emissions it's ok lol!

Bristol98

The only cat on a classic is in the downpipe, the centre is a resonator....

If its a UK classic you should be able to get away without a remap if you are only after the noise, I ran a MY98 classic uk saloon for three years with a decat and no issues...

MR2Mk1

iTrader: (1)

I'm more interested in better running and increased BHP without the noise if possible since prefer the car to be more discreet which is why i replaced the noisy original box for the Prodrive

MattyB1983

iTrader: (51)

Read post 11 again, nothing more needed.

I would not advise removing cats without having the map adjusted.

MR2Mk1

iTrader: (1)

So if I just put a sports cat on the front the car would still run Ok but if I wanted to gain any benefit I would have to up grade fuel pump and re-map I presume?

Can you get a routine tune or diagnostic check done on them to make sure everything is running normally in factory standard since 1st re-map looks like £550 which seems rather expensive?

Infected by sti

iTrader: (6)

You have to pay for a one off licence fee on the ecu which enables you to run a different map, once licence fee is paid it is then the cost of your map depending on tuner and time scale, probably the best £500 you spend when it puts a smile on ur face like a Cheshire cat

MR2Mk1

iTrader: (1)

Could i fit a Sports cat without having to remap the car since cant really afford £500+ at present and would it improve anything if i did without remapping?

MR2Mk1

iTrader: (1)

Would fitting the sports cat to the original centre section resonator keep the noise down but still give the better turbo wind up time reducing turbo lag?

joey_turbo

iTrader: (26)

Not true. On a classic PPP, the centre pipe is a resonator, but on standard UK's, its definitley a cat.

I thought some of the "freindly MOT garages" actually swap the centre section for the catted centre section, as its quicker than downpipe off.

MR2Mk1

iTrader: (1)

So i could get away with a cheaper de-cat front pipe if the centre section is a CAT and it will still pass MOT?

joey_turbo

iTrader: (26)

Possibly, although most sports cats are the downpipe type, so there must be a reason for that. Probably to maintain heat i'd imagine. Because a centre pipe may lose its effectiveness from being in a colder location.

joz8968

iTrader: (13)

Yeah, Zen (when they were based in Baird Court) used to do that for customers that had booked an MOT through them.