Smart 51
the lambada sensor is on the exhaust manifold so as you suggest the engine won't notice the difference.
l0rd
I would think about removing both but I am not quite ready to make an entire exhaust manifold
Ok guys I have a simple question on my car i have the standard double cat set up from the Nissan Pulsar donor (there is a cat in the exhaust manifold
and a second one just before the first muffler.) Now I am considering deleting the second one when I rebuild the car in a couple of weeks and
replacing it with a new section of 2 1/2 stainless tube that I just picked up at my favourite scrap metal place.
I am unconcerned about increased emissions because there is no annual testing where I live but I do wonder if it will make any difference to the
tuning ?
Any ideas or experience out there?
I just think that since I am making a pretty new body
for the car that I should have a better looking exhaust as well.
[Edited on 10/6/09 by niceperson709]
when i took the cat and silencer off my car it ran better, the throttle response was noticeably sharper and it seemed to accelerate faster.
If i was you, I would remove both. Specialy the one in the manifold.
Is there a lambda sensor after the second cat? No? Then the electronics won't know it has been removed. In which case I'd have thought it
would be OK.
As for an increase in emissions, I doubt it. Cat converters change CO and partly burned fuel into CO2 - one form of pollution into another. The
total volume doesn't change. Removing the cat may even reduce your fuel consumption slightly, reducing overall emissions.
Thanks guys what you have been saying matches what I have been thinking.
Smart 51
the lambada sensor is on the exhaust manifold so as you suggest the engine won't notice the difference.
l0rd
I would think about removing both but I am not quite ready to make an entire exhaust manifold
After having a discussion with my mechanic about improving the performance of my Laguna 1.8 16v, He adviced me to change the manifold to a 2.0L one
and also to stick a bar through the manifold cat.
The only worry will be when you do an emission test, in order not to fail, you need to have the car warmed up and the normal cat should be perfectly
all right for the test.
I have seen on a Dyno, a Renault Megane II 1.6 (115HP factory claim) that produced 123HP without the manifold cat and 128HP with an unbranded
induction kit.
I am not saying that you can do that. I am not to be held responsible if anything goes wrong. This is what i was told and what i have seen.
[Edited on 10/6/09 by l0rd]
quote:
Originally posted by niceperson709
Thanks guys what you have been saying matches what I have been thinking.
Smart 51
the lambada sensor is on the exhaust manifold so as you suggest the engine won't notice the difference.
l0rd
I would think about removing both but I am not quite ready to make an entire exhaust manifold
l0rd
I had not thought of getting handy with an iron bar to the cat matrix in the manifold but it would reduce restrictions in the exhaust without altering
the appearance.
so thanks fro the idea
Just try to get hold of a second one if possible. You do not want to get any ECU errors.
I had a MR2 turbo, broke the cat up in situ within the manifold, it made the car much faster, turbo spooled up really quickly and made no difference
to the ECU.
Regards Mark
quote:
Originally posted by niceperson709
Smart 51
the lambada sensor is on the exhaust manifold so as you suggest the engine won't notice the difference.
quote:
Originally posted by smart51
Some cars have 2 sensors, one before and one after the cat. It uses the second sensor to fine tune the fuelling. You'd probably need to leave it alone.
quote:
Originally posted by MikeRJ
quote:
Originally posted by smart51
Some cars have 2 sensors, one before and one after the cat. It uses the second sensor to fine tune the fuelling. You'd probably need to leave it alone.
This is found on OBDII equipped cars, and is to tell the ECU how well the cat is working, i.e. it's purely for emissions warning than fuelling.
My Kia failed on emissions last year and when I took the front pipe off it was completely hollow. I replaced the cat and can say it has not made a bit
of difference to performance or noise (it's still noisy and slow )
quote:
Originally posted by smart51
Are you sure? I'm fairly certain that Euro 4 and 5 cars fine tune their fuelling for aggressive emissions limits by looking at the excess air both sides of the cat.
Failed emmisions without a cat is usually down to a lazy lambda sensor, they should be replaced on a regular basis but just get left alone.
Regards Mark
Emissions is not an issue Mark because they do not test for that here.
Thanks to all here for your help, it looks like one cat will go in the bin and the other will be getting the iron bar treatment
quote:
Some cars have 2 sensors, one before and one after the cat. It uses the second sensor to fine tune the fueling. You'd probably need to leave it alone.
