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what gains would you get from decat and aftermarket back box

J

joemac

Messages
42
as above, what bhp would you expect to see without changing manifold, 15? Also I'm after a exhaust which isnt too loud but a bit louder than standard.Any recommendations?
 
A decat will make it very loud.

Ideally any cat back system with a silenced centre section (B Pipe) wont be too loud, but will sound good. Also depends on what exhaust tip you want?
 
Lots of threads and posts like this all over the forum, please search.

To answer you question quickly;

Never in a million years will you get a gain of 15bhp with just a decat and cat back exhaust. You will need a aftermarket ECU to adjust the fueling to squeeze out the extra power, also, the biggest area to extract power from will be the manifold/header by leaving that OEM you won't get the maximum benofit of having no CAT and a larger bore CAT back system.

Get a Fujitsubo RM01A if you want a subtle sounding system.
 
Ive just fitted decat with a full magnex system (including silencer). Isnt too loud. Its the only mod on the car and the mid range seems a bit more punchy :)
 
Me thinks the extra noise is making you think you're going faster. If you're gonna gonna de-cat it, might as well change the manifold as well.

Iam planning on getting K100 at tdi north with just a tegiwa airbox and catback, probly get 15bhp if im lucky and thats with the ECU. Just want a more all round car.
 
Earthslug, do you have any dyno printouts before and after to prove what you're claiming?
 
Last edited by a moderator:
If your decatting a car reset the ecu usually takes 10-15 minutes. You will notice a difference less torque low down.
 
Suits said:
Lots of threads and posts like this all over the forum, please search.

To answer you question quickly;

Never in a million years will you get a gain of 15bhp with just a decat and cat back exhaust. You will need a aftermarket ECU to adjust the fueling to squeeze out the extra power, also, the biggest area to extract power from will be the manifold/header by leaving that OEM you won't get the maximum benofit of having no CAT and a larger bore CAT back system.

Get a Fujitsubo RM01A if you want a subtle sounding system.
Click to expand...

I have a dyno print from Tdi using my OEM ECU and my mapped K100. The only breathing mods I have are AEM CAI and supersprint B-pipe. It made 217bhp with the OEM ECU and 223bhp with the K100.

This is all.
 
Hazz said:
I have a dyno print from Tdi using my OEM ECU and my mapped K100. The only breathing mods I have are AEM CAI and supersprint B-pipe. It made 217bhp with the OEM ECU and 223bhp with the K100.

This is all.
Click to expand...

What did the full OEM car run ??

216bhp I suppose.

You will not get a improvement of 15+ HP from an intake and b pipe.

This is all.
 
Well that's the million dollar question isn't it. I suppose we might get to see an OEM on the rollers on the 5th of november which will give us a better idea. Until then, I'm not ruling it out. I've seen stranger things on the rollers at minisport.
 
is there a problem in putting getting a decat on my ep3 in terms of my sensor at the cat does this effect anything with out a remap?
 
On some Forums they say that a Decat on a K-motor will lean the A/F Mixture so a remap is very suggested.
 
I ran a dc manifold on mine for a few months before I had it remapped and it was fine.
 
I would have thought the ECU would adapt. Might be worthwhile pulling the battery to reset the ECU.
 
The ECU can only adapt what the Lambda can read and the problem is with decat and Stock Lambda it will put an ECL on so you have to get the lambda out of the "stream" in the exhaust system and it doesn´t read the correct information out of them.
 
On the ATR, we just put a spacer in the decat. No ECL lights or anything like that, having said that when my DC5 was de-catted I had kpro fitted at the same time.
 
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