E36 decat

pitesy

pitesy

Member
Hi!

When decatting a 325i, should I cut the cats and the center boxes too? Or just the cats? If I remove the center boxes will it reduce the low down torque even more?

I've got this type exhaust (I saw single center boxed ones too)
november_2007_robbies_turbo_build_day_01%20019.jpg


Thank you!
 
The centre boxes are just resonator boxes and hollow.

From my experience, don't decat it! You will lose so much low down torque. I did mine, hated it, cats back on! Don't waste your time
 
Thank for the answers!

That doesn't sound good... I looked for decatting on other forums too, and the results were mixed.. Someone said it got better, the other one said it ruined the idle, and the car lost power..
I'm confused about doing it or not.. :confused:
 
Dunno but are you keeping that exhaust? Ill have it if you're not :wack:
 
I have that exhaust on my 328, but ive only hacked the back box off and welded pipes on, slightly (hardly noticeable) more responsive but holy fuck its loud and very raspy, i like :) left my cats alone as i think one is dying anyway.
 
warby said:
I have that exhaust on my 328, but ive only hacked the back box off and welded pipes on, slightly (hardly noticeable) more responsive but holy fuck its loud and very raspy, i like :) left my cats alone as i think one is dying anyway.
Click to expand...

I was thinking about this for my 328 Vert :nod:

Since I work at a police station, does it end up being obviously illegally loud? Does it pass an MOT with it on?

Im thinking that being a vert, ill get fedup of it very quickly but it depends how loud?
 
Also very interested in this. Does anyone know of the best exthaust mods (what parts to remove) for the best increase. Don't really care how loud it is but has to be cheap as im broke!!
 
- Fezcat - said:
I was thinking about this for my 328 Vert :nod:

Since I work at a police station, does it end up being obviously illegally loud? Does it pass an MOT with it on?

Im thinking that being a vert, ill get fedup of it very quickly but it depends how loud?
Click to expand...

We have no mot so can't comment, I'll get a vid in the week. Can be driven 'quietly - ish' into work, sneaking home late etc.

For over here and the fact that most uk coppers don't give a toss about us Manx oddities, I'd say I'm ok to be fair.


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Im going to see another 328 coupe tomorrow as a spares breaker so might take backbox off that and open it up see what's what regards making the standard box louder :)


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I'm looking forward to the imperssions Warby!
Thank you for the answers guys!

I made a research again, and I found a US forum, where are dyno tests, and mods for e36's.
Here is the link: [ame=http://forums.bimmerforums.com/forum/showthread.php?t=478545]E36 Dyno Sheet Library - Bimmerforums - The Ultimate BMW Forum[/ame]

I read it all the way through. It seems that a cold air intake, a chip, headers, and a decat will improve torque and hp above 4000. The next level is cams (here s50 cams, mint it is a US site), underdrive pullies, fan delete mod and so on...

I hope I helped someone, because I was pretty confused about it.

The only thing that isn't clear, the diameter of the exhaust pipes.. If someone knows something about this, please write it! I'll continue my research and if someone would like it, I'll post here, what I found.
 
Sorry to bump an old thread but I'm looking at decatting my 325i and I'm still a bit confused as to whether I should. I'm planning on going for a shotgun style exhaust with straight pipes and no back box. Will this hinder my performance at all?
 
at the end I took the cats out. on higher rpms it pulled a bit stronger, on lower rpms had a bit less torque. that`s it. :) and it was really loud with an empty backbox. i hope I helped you out.
 
victim said:
Sorry to bump an old thread but I'm looking at decatting my 325i and I'm still a bit confused as to whether I should. I'm planning on going for a shotgun style exhaust with straight pipes and no back box. Will this hinder my performance at all?
Click to expand...

tbh dude for the hassle thats involved, leave them in and just whack straight pipes on the end :thumbs:

I know its an M3 but give you an idea
 
Last edited by a moderator:
imho that the above sounds wack! id take the cat and get a remap + i wieghed mine in for 90 notes:thumbs:
 
I think I'm just gonna run a shotgun rear section atm for ease and perhaps run a straight through at a later date
 
An interesting thread that seems to be giving mixed views....I have a 1996 323 and I'm thinking of taking the cat out, replacing it with a silencer and using a straight through section to the back or possibly an old motorbike silencer I have lying around as the backbox.
 
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