I'm Confused

[Jones_XD]

Reading MANY threads on removing the cats on DC5's on here.

And there are so many people saying don't bother unless you got k pro ECU??

then others saying the got good gains on standard ECU etc

I know my mate on his EP3 de catted his k20a and had to use a o2 simulator, now some people say on here that is just pick of a hat is the engine management light comes on and some people say that the DC5's can cope without the O2 sensor mod.

so needless to say Im rather confused on the matter lol

was gonna order a de cat pipe off funky power for £130 delivered? that a good price or there other companies out there making them.

Can someone please try and clear the matter up before i go ordering it without the O2 sensor mod

This is the de cat pipe I'm looking at, is it correct

http://www.funkypower.co.uk/catalogue.php?make=HONDA&model=INTEGRA&year=2001%2B+DC5+INTEGRA+TYPE+R&level1=EXHAUSTS+%26+EXHAUST+MANIFOLDS&level2=HIGH+FLOW+CATS%2FCAT+BYPASS+PIPES&level3=&id_product=5480

Thanks :xgrin: :xgrin: :xgrin:

 

[beppe786]

mine was de-cated on oem ecu and it was flying my engine light didn't come on.. Tom at TGM said they dont come on like the ep3

just buy an complete header..

 

[Jones_XD]

mine was de-cated on oem ecu and it was flying my engine light didn't come on.. Tom at TGM said they dont come on like the ep3

just buy an complete header..

yeah was thinking about it, seen compete header with decat for £219.99 delivery not sure what make it was tho

 

[scottj15]

A Decat will increase performance as it increases the flow rate of air through the engine. The quicker you can get air in and out of the engine, the more power you'll produce so anything that constricts this flow (such as a cat) will hinder this. This logic works up to a point. If your straight through system bore size is too large or you haven't got a suitably matching cat-back you are prone to problems with back pressure and this is when you can start to lose performance.

Weather the engine management light comes on or not will depend upon the other mods and setup of your car. At the end of the day it comes on because your emissions are running too high and anything from the type of oil to the time of day you start the car can affect this. When I had my civic I had a high flow cat fitted which kinda sits in the middle of a full cat and a decat. This didn't trigger the Engine light until I had stage 1 cams fitted. Then every now and again (usually when I put my foot down to soon after starting it) the light would come on.

A lot of people (Me included) are put off decats for a number of reasons a) because their illegal in the UK and will fail an MOT due to emissions b ) they can increase exhaust sound levels above that of a track day limit especially with an aftermarket Cat-Back.

I personally will be looking at High flow cats or nothing when I get round to that side of things just because of the MOT and engine light implications that come with a Decat

This is my own opinion of course, some may disagree or argue against, hope it helps

 

[Jones_XD]

This what your on about ???

http://www.japspeed.co.uk/Honda-Civic-Type-R-4-2-1-SS-Tubular-Race-Manifold-and-Decat-Downpipe/p-0-160/

i know it say EP3 but they the same on the DC5??



A Decat will increase performance as it increases the flow rate of air through the engine. The quicker you can get air in and out of the engine, the more power you'll produce so anything that constricts this flow (such as a cat) will hinder this. This logic works up to a point. If your straight through system bore size is too large or you haven't got a suitably matching cat-back you are prone to problems with back pressure and this is when you can start to lose performance.

Weather the engine management light comes on or not will depend upon the other mods and setup of your car. At the end of the day it comes on because your emissions are running too high and anything from the type of oil to the time of day you start the car can affect this. When I had my civic I had a high flow cat fitted which kinda sits in the middle of a full cat and a decat. This didn't trigger the Engine light until I had stage 1 cams fitted. Then every now and again (usually when I put my foot down to soon after starting it) the light would come on.

A lot of people (Me included) are put off decats for a number of reasons a) because their illegal in the UK and will fail an MOT due to emissions b ) they can increase exhaust sound levels above that of a track day limit especially with an aftermarket Cat-Back.

I personally will be looking at High flow cats or nothing when I get round to that side of things just because of the MOT and engine light implications that come with a Decat

This is my own opinion of course, some may disagree or argue against, hope it helps

yeah i understand what you'r saying my teg has a fujitsubo giken cat back on it and it's really quite even in vtec i want the noise level a bit louder but not stupidly loud.

My mate said a de cat made a huge difference on his EP3 and i wouldn't regret doing it on the integra especially because i already got a good cat back system. :xgrin:

 

[beppe786]

i looked into this a while back. some people say you need back pressure and some say honda engine don't suffer from it and wont lose any power..

choice is your from my experience my cat was blocked so i had to take it off.. exhaust does get louder, but depends if its silly loud on your exhaust..

my friend owns a mot station so i don't have that problem / performance wise more better flow in and out the better..


yeah thats the one go.. for dc sports or tegwia toda copy

 

[El_Boomo]

It's not back pressure you need, it's exhaust gas velocity. It's a common misconception.

 

[Brophy]

As said go for the full manifold which has no cat.
Also don't spend that much on a no name one.

There's a dc sports manifold on eBay justnow for £250.


P.s Engine mount inserts recommended.

 

[Jones_XD]

Thanks guys , thought it was a japspeed header but it's a non branded I take it ??

Was you mean engine inserts does it require another mod to fit the manifold ??

 

[Mark_teg]

The reason a de-cat is not recommended on the K20 without Kpro (or equivalent) is due to fuelling!

The increase in airflow can result in the engine running lean. The ECU can and will adjust, but only to a certain point! This point will vary for every engine so difficult to say if you're safe with X-Y-Z.
After breaching this point you run the risk of premature engine failure.

Kpro allows the fuelling parameters to be adjusted to suit.

Hope this makes sense.

 

[leejw87]

an engine doesn't need back pressure it just requires a good balance of being able to FLOW exhaust gas at reasonable VELOCITY (speed)

For example if you put a big wide exhaust on a car it will flow better but at a lower velocity so torque may be low.

If you have a small diameter exhaust the flow will be restricted but the velocity will be greater so torque should be better

 

[Jones_XD]

What are people thoughts on sport cats then ?? Do they still help with the fueling situation ?

 

[Bonito]

With no ECU some headers and Decat mods cause the engine to run rich top end. If you like running rich between 6500+ then go for it.

 

[Turbosnatch]

The reason a de-cat is not recommended on the K20 without Kpro (or equivalent) is due to fuelling!

The increase in airflow can result in the engine running lean. The ECU can and will adjust, but only to a certain point! This point will vary for every engine so difficult to say if you're safe with X-Y-Z.
After breaching this point you run the risk of premature engine failure.

Kpro allows the fuelling parameters to be adjusted to suit.

Hope this makes sense.

With no ECU some headers and Decat mods cause the engine to run rich top end. If you like running rich between 6500+ then go for it.

So... Rich or lean?

 

[Jones_XD]

With no ECU some headers and Decat mods cause the engine to run rich top end. If you like running rich between 6500+ then go for it.

CAUSING DAMAGE OR JUST USE ALOT MORE FUEL?

 

[Bonito]

CAUSING DAMAGE OR JUST USE ALOT MORE FUEL?

I'd expect detonation eventually on low octane fuel.