de-catting exhauts

davkav

Right was just wondering is there any way of de-catting a car without having all that noise coming out the back. A couple of friends have it done and they sound like spitfires going by to be honest. I read somewhere that the quicker you let the exhaust fumes out the better, i.e. exhausts with less bends and less restrictions to the airflow. Now im talkin 2.0T spec so not a little civic so if it gives a whole load of performance boost im doin it.

JohnCleary

Its worth doing alright, even on a 1.6 I notice the power gain.
Just remember youll need to put the cat back on for your NCT to try to get a proper de-cat pipe with flange as opposted to a weld job so you can easily put your cat back on

Balfa

It's also illegal, from an emissions and noise point of view. All cars sold after some time in the mid '90s have to have one.

You'll probably gain about 2 to 4hp, depending on the design of the engine and catalytic converter, even with forced induction.

secret_squirrel

A good way to do it used to be fill the car up with Leaded a coupla times. It degrades and eats away the cat material until most of it comes out. Obviously this wont help come NCT time.

JohnCleary

secret_squirrel wrote:

A good way to do it used to be fill the car up with Leaded a coupla times. It degrades and eats away the cat material until most of it comes out. Obviously this wont help come NCT time.

:eek:

AlienGav

davkav wrote:

Right was just wondering is there any way of de-catting a car without having all that noise coming out the back. A couple of friends have it done and they sound like spitfires going by to be honest. I read somewhere that the quicker you let the exhaust fumes out the better, i.e. exhausts with less bends and less restrictions to the airflow. Now im talkin 2.0T spec so not a little civic so if it gives a whole load of performance boost im doin it.

What kinda car are we talking about?

I reckon if u really wanna eeeek out some extra ponies from your your exhaust, a full-on mandrel bent, full exhaust system from your manifold would be best!

Altho a little pricey! Depends really on your jam jar, I'd have a look and see if any big names like Blitz or HKS make exhaust systems for your car :cool:

davkav

getting a silvia S15 2000 2.0t so lookin tog et the most out of the engine

Ratchet

Balfa wrote:

It's also illegal, from an emissions and noise point of view. All cars sold after some time in the mid '90s have to have one.

You'll probably gain about 2 to 4hp, depending on the design of the engine and catalytic converter, even with forced induction.

well, in Ireland nobody checks that CAT is still fitted

NCT only cares about emissions levels

blastman

This is true. Ratchet de-catted my exhaust a while back and it still passed the emissions test at NCT time, no problem.

d4r3n

The CAT on my car just died, makes more noise which was weird at first but my NCT isn't due till 01/07 so Im not going to bother fixing it.

AMurphy

Leaded fuel will not "eat the insides out", just kill the thin layer of material in teh honeycomb.
It may also kill your O2 Sensor, which will then throw out your EFI.
In addition, the free flowing ex gas can have a big negative effect on the life of your ex valves, particularly if your engine is also fitted with an EGR system and as the back pressure is no longer there the EGR system will probably fail to function properly, increasing the exhaust gas temp even further, shortening the valve life even more so.

Probably gain about 5HP max.

Ernie Ball

blastman wrote:

This is true. Ratchet de-catted my exhaust a while back and it still passed the emissions test at NCT time, no problem.

Who or what is Ratchet?

Dub_Ster

davkav wrote:

Right was just wondering is there any way of de-catting a car without having all that noise coming out the back. A couple of friends have it done and they sound like spitfires going by to be honest. I read somewhere that the quicker you let the exhaust fumes out the better, i.e. exhausts with less bends and less restrictions to the airflow. Now im talkin 2.0T spec so not a little civic so if it gives a whole load of performance boost im doin it.

get a mongoosse system from the down pipe back it will make a bit of noise but thats what sound deadining is for and a bit of that on the boot floor and ya wont notice a thing ......... oh an if its an sr20det model iotle pass the nct with one cause my brother one has . ps i drive a civc ! but id still take the urnl all over you cause you aint got no traction for action .........

balfa its also ilegal for a politon to get away with drink driving is it not ?

Balfa

Ernie Ball wrote:

Who or what is Ratchet?

*snigger*
look four posts above your own.

Ratchet is electro-plated with a chrome-nitride coating in a vacuum champer using a physical vapour deposition system.

Ernie Ball

Balfa wrote:

*snigger*
look four posts above your own.

D'oh!

Ratchet, are you a mechanic?

I'm eventually going to need to gut the pre-cats from the exhaust manifold of my MR2 and I'm not sure I'm up to the task. I'd pay someone to do the job properly.

CrowdedHouse

Will someone please think of the Envoirnment

BTW Ratchet - the Signature Police are after you :eek:

Ratchet

Ernie Ball wrote:

D'oh!

Ratchet, are you a mechanic?

....QUOTE]

nope, i just live in the garage



anybody thiniking about doing this mod, has to use proper de-cat pipe as there is no of point modifiying existing CAT(removing honeycomb) which makes things worst.

i may just know somebody with spare decat for sale, will check that for you.

Dub_Ster

CrowdedHouse wrote:

Will someone please think of the Envoirnment

tell that to george bush ......

Ernie Ball

Ratchet wrote:

i may just know somebody with spare decat for sale, will check that for you.

Actually, what I'm looking for is someone to remove the exhaust manifold, clean out the ceramic pre-cats (not the cat itself) and reattach the manifold.

It's not the sort of thing you can ask an ordinary garage to do.

Anyone have any ideas of where I could have this done?

Ratchet

Ernie Ball wrote:

Actually, what I'm looking for is someone to remove the exhaust manifold, clean out the ceramic pre-cats (not the cat itself) and reattach the manifold.

It's not the sort of thing you can ask an ordinary garage to do.

Anyone have any ideas of where I could have this done?

is this turbo model?

Ernie Ball

Ratchet wrote:

is this turbo model?

2001 Roadster. Not turbo.

Ratchet

Ernie Ball wrote:

2001 Roadster. Not turbo.

new type mr2, less work then

Do you really need to do it? it's enough work for the actual gain.

anyway , it could be done if you want

Ernie Ball

Ratchet wrote:

new type mr2, less work then

Do you really need to do it? it's enough work for the actual gain.

anyway , it could be done if you want

I need to do it not for any performance gains (the car is fast enough as is:D) but because these precats are a known defect in this car. Lots of reports of the ceramic material breaking up and getting sucked into the engine, which then would need to be replaced. I'd rather get the time bombs out of the car than face that.