E46 325i Decat

[Epoc]

Has anyone decatted their 325i as yet? It has been recommended by many on the forum and thanks to those that have given me info/recommendations.

What i want to know specifically is 1) car tone/exhaust sound has it made a big difference, for the better or worse, i don't want it to sound like an aftermarket exhaust.

2) where to do it for a good price, i have been quoted R1500 for each cat to be removed, totaling R3000, so not sure if worth it or not.

3) should the decat be done on both front and rear cats?

4) will it cause problems i,e, error lights coming up,air flow mixture problems?

5) any noticeable performance increase or fuel economy difference?

Thanks guys.

 

[StK]

If you decat your car then you will probably need a remap too or else the ECU will go onto a default setting and your car will overfuel drastically...Your MPG will go up considerably...If you are going to decat then remove all the cats...fortunately AFAIK SA doesn't have emmissions testing so you won't need cats at all...unless you have a remap you may have an engine check light come on...and with a remap you should see some good gains...sound wise there will be an increase in sound but as long as you keep the rear silncer then it shouldn't be too loaud

 

[nawtiboy]

i did my ci a while back

only took out 2 -

a very slight difference in tone when you gun it -otherwise normal

my onboard dropped from 18.5 to 16.2l -with just the cats removed

a bit more pluk - mid to high range

-depending on where you do it -it can be done without the chip

but i suggest you do both-it's well worth it

i paid just over a 1300 to remove and fit 2 small silencers -:hammerhead:

total was under 5k with an induction:shocked:

i did it at SAC.S MIDRAND:mmm: - yes i know:thinking: - they still tune all my cars :shocked:

i'm sure other fanatics has done it as well:thumbsup:

 

[hiltonfa]

Remove all the cats, the car will be louder but not to much, depending who does the job, there are sensors available that are installed in the system which send a signal to the ECU that the cats are in fact still in place. No remapping is required.

 

[gizmowp]

go for it...im keen on doing this to my 325ci...


but i want a nice grunty exhaust note...not too loud..just a burble...

 

[Kamz]

I had a e46 325ti and i had the exhaust cats in the middle only removed. Made a sound difference which sounded quiet nice and it does help with fuel if the cats are clogged! I was told if i want to decat the manifold then they will have to put in a mini cat because of the sensor.
I only paid R150 at a superquick to remove the two cats by the middle box and replace with a straight pipe. To me R3k is to steep!!!

 

[gizmowp]

geewizz...R150 @ superquick..damn good price

i think they keep the cats and sell them cos they made of platinum

 

[veridico]

They sell the cats for R300 each, because of the platinum content. They should remove them for free. Or when they quote you, tell them you want the cats after they have removed them, then they will change their tune.

 

[netercol]

If you decat your car then you will probably need a remap too or else the ECU will go onto a default setting and your car will overfuel drastically

uh.. why???

 

[sclass]

So what's a fair price for a decat? Apparently Noise Boys do it for +/- R600? Rob Green conversions add R3000 to the total cost if the car has a cat...Ludicrous! But is cheaper better in this case? I eventually want to remove them off my 530 though I'll admit it was mainly for the gruffier sound, but if there are fuel economy + performance benefits then there seems to be no reason NOT to do it...except of course PRICE! So what's the verdict? Supaquik?

 

[StK]

If you decat your car then you will probably need a remap too or else the ECU will go onto a default setting and your car will overfuel drastically

uh.. why???

Lambda sensor

 

[netercol]

let me re-phrase that.. if you have a lambda sensor in front of the cat it will make no differance to the management. only if you have a lambda post cat too, then you have to fool the management into thinking the cat is still there.. do any of our S.A cars have lambda probes post cat? :dunno:

 

[StK]

let me re-phrase that.. if you have a lambda sensor in front of the cat it will make no differance to the management. only if you have a lambda post cat too, then you have to fool the management into thinking the cat is still there.. do any of our S.A cars have lambda probes post cat? :dunno:

Fair enough there are E46's here(UK) with up to 4 lambda sensors pre and post cat and we have emissions test's every year too..If you don't have a post cat lambda sensor then you won't have to worry about overfueling as much but without the CAT's even pre cat lambda sensors will sense a fault and will go into a default setting(open map) thinking that there is a problem with the sensor if you remove the cat's

 

[mcompact]

would a e36 328i manifold fit on a e46 325? that way you wont have to cut cats out from manifold.

 

[Rossouw]

Just for info.....helped to decat a nissan bakkie with a lamda sensor, just remove the cat box and sensor,remove cat core....... replace box, system looks standard but cat removed. Exhaust note changed very little but power is much improved.

 

[maduna]

Remove all the cats, the car will be louder but not to much, depending who does the job, there are sensors available that are installed in the system which send a signal to the ECU that the cats are in fact still in place. No remapping is required.

Where can I purchase such sensors, I would like to remove my cat asap but I don't like this remap story.

Thanks

 

[Ralf*]

it all depends on the configuration of your exhaust system

1) If you have CATS that are co-located on the manifold with sensors integral to the CATS, then you can either a) remove the manifold, then "hollow out" the CAT, ie remove the internal platinum stuff, and then replace it, it will still look exactly the same.....I think we would charge about R600 per CAT to hollow out the internal stuff, mainly a labour job with new manifold gaskets and some welding....or you could change the entire manifold for a set of branches from VIPER or utilize a set of E36 328i headers, as these have fittings for the sensors..........in both cases no re-mapping is necessary

2) If you have CATS situated under the car, about mid distance, then these are generally not fitted with any sensors, so a straight forward cut and replace with a straight piece of exhaust pipe....about R150 per CAT/Pipe or you could substitute the CATS with a freeflow box, for another R350-R400 or so

In all cases the sound will not change by very much, as most of your cars "REAL" sound changes and silencing is derived by the rear box

 

[Maljan]

From what I've heard you take out the cat, replace with a piece of pipe that has a fitting for the lambda sensor, put the old sensor back in and hit the road. But that might not apply to BMWs. Is the sensor an integral part of the cat?

 

[Nikhil]

Holy 5 year old thread bump :hammerhead:

 

[ET was here]

Holy 5 year old thread bump :hammerhead:

search function, and adding value to an existing topic, is probably better than starting a new topic all over again, and then repeating all the information