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OEM manifold with de cat and map ??

S

supercharged999

Messages
36
Hi all

I have been loads of re search on here with regards to modding my ep 3.

However has anyone just added a de cat pipe to the OEM manifold and system with a hondata map ??? and what were the results.

The stock system seems ok , just the cat is the major restriction...

Thanks
 
Waste of time, I did it about 10 years ago and made hardly any power when remapped. Race header is the only way to make the real gains.
 
As above, if you are going to remove the cat anyway you might as well remove the full OEM manifold and replace the lot with a header.
 
Would I need to get the kpro done in order to put a full decat system from manifold or can I install it without map???
 
Physically you can in stall it. You will get the EML on for a cat fault (as there will be no cat) although you can fit a spacer/O2 sim to get round that. What that doesn't get round is that the exhaust will work better at letting the gasses out of the engine which in tern means that more air will be scavenged into the engine from the intake side, the ECU cannot compensate for this and so cannot throw enough fuel in to keep the air to fuel ratio constant, meaning the car will run lean.

Car running lean leads to knock, leads to overheating cylinders, leads to cracked pistons/valves/head, leads to engine go boom boom.

Aside from the increased likelihood of knock, you also won't make the big gains in power that you would if it mapped properly, as above, the AFR is too lean to make the power.

So, people do run a decat and/or race manifold without a remap, but I would strongly advise against it. If you want to go Hondata you could use K100/Kpro. With either of those you won't get the EML either as the mapper will turn off the secondary O2 sensor.
 
Loxy said:
Physically you can in stall it. You will get the EML on for a cat fault (as there will be no cat) although you can fit a spacer/O2 sim to get round that. What that doesn't get round is that the exhaust will work better at letting the gasses out of the engine which in tern means that more air will be scavenged into the engine from the intake side, the ECU cannot compensate for this and so cannot throw enough fuel in to keep the air to fuel ratio constant, meaning the car will run lean.

Car running lean leads to knock, leads to overheating cylinders, leads to cracked pistons/valves/head, leads to engine go boom boom.

Aside from the increased likelihood of knock, you also won't make the big gains in power that you would if it mapped properly, as above, the AFR is too lean to make the power.

So, people do run a decat and/or race manifold without a remap, but I would strongly advise against it. If you want to go Hondata you could use K100/Kpro. With either of those you won't get the EML either as the mapper will turn off the secondary O2 sensor.
Click to expand...
Also any ideas on how much the remap is.. Can I pick up a used k100 ecu??? Or map the stock ecu?
 
You can buy a second hand ECU with the K100 fitted. But then you'll need the immobiliser coding and then mapped to your modifications.

A new K100 fitted plus mapping is £720 from TDI North. I think Eurospec is slightly cheaper.
 
What bout if install the decat exhaust without manifold would i still need mapping it's confusing some people are not mapping cars and adding mods and also 720 is alot for a ecu and map.
 
You can get away with running a decat or full race manifold without remapping. Yes it leans out slightly but not enough to cause any damage. Larger intakes and bigger inlet manifolds is where you go into the danger area including your race exhaust manifold.
It is expensive to map these. But the K100 alone is around £400 and the map is custom tuned to your exact car. Not like these generic Revo maps ect.
 
Lewisgame said:
You can get away with running a decat or full race manifold without remapping. Yes it leans out slightly but not enough to cause any damage. Larger intakes and bigger inlet manifolds is where you go into the danger area including your race exhaust manifold.
It is expensive to map these. But the K100 alone is around £400 and the map is custom tuned to your exact car. Not like these generic Revo maps ect.
Click to expand...
Well a k and n intake and buddy club decat leaving manifold would this be fine without remap.. Or will the eml light still come on?
 
The engine management light will come on as there's no cat. You can fit a spacer to the secondary lambda so the light doesn't come on. It's not ideal but it works.
You're best off saving up for all the parts and the K100. Fit the parts just before your mapping session.
 
Lewisgame said:
The engine management light will come on as there's no cat. You can fit a spacer to the secondary lambda so the light doesn't come on. It's not ideal but it works.
You're best off saving up for all the parts and the K100. Fit the parts just before your mapping session.
Click to expand...
Hmm what bout the o2 sensor. Well i didn't know bout this k100 mapping issue need to see what others have to say on here.
 
Lewisgame said:
The engine management light will come on as there's no cat. You can fit a spacer to the secondary lambda so the light doesn't come on. It's not ideal but it works.
You're best off saving up for all the parts and the K100. Fit the parts just before your mapping session.
Click to expand...
You can fit a spacer to the secondary lambda. Could you please give me more info on what this is mate thanks.
 
They both do the same thing. One is a spacer that puts your lambda sensor out of the gas flow of the exhaust, the other you solder onto your lambda sensor wire to so it sends an "OK" signal to the ECU.

Neither will affect the fuelling of the car and both will make it run lean when used with a race header. One is easily fitted and reversed, the other means cutting your loom.
 
I'm not using the header only was thinking of running buddy club exhaust without the cat but I think I should leave the cat in. What's main difference with cat and decat apart from running lean?
 
Cat is more restrictive and it suppresses some noise as well of its primary function of reducing exhaust emissions to a legal level.
 
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