De-cat info please.

[Spannermonkey]

Ok, I've found me a decent bit of pipe to insert into the space left by the cut-out middle cat, and i've left in the lambda sensor.
1) will i need to fit a "fool-it" mod to stop the engine management light coming on?
2) if so, where do i get one, and how much?
3)how will it change the way the car runs, and will I need induction or jetting changes?
4)If I change the std filtering to an induction kit, will that affect the EM unit too?
5) Lastly (sorry) All my vis motors are ok, and my plenum APPEARS good, so apart from an oil catch tank that I have already fitted, is there anything that will keep them that way (sort of insurance)??

Thankyou in advance for advice.:thankyou:

Mike.

[garymgzs180]

hi mate.
1 i have had 2 zs 180 and fitted decat pipes on both. my first one the eml did not come on but on my current car it did. from speaking to people i have found some cars do and some dont. my car still passed the emmisions on the MOT beacuse of the pre cat in exhaust manifold so that should not be a problem. ptp do a mil eliminator for about £25 which will sort the problem if the light does come on. but dont forget that once the light comes on you will need the necessary computer to clear the light. might cost you to get it cleared

3 having fitted a decat will not affect the engine or ecu other than the fact the exhaust will flow better. that after cat sensor is only there because of laws regarding emmisions and manufacturing. it is only there to check that the cat is performing ok and so when the cat fails the light comes on and you go to the garage to get it looked at and dont keep driving around unaware your polluting the atmosphere. as i say you could remove the sensor completly and it does not affect fuelling or timing. it is only the first 2 sensors (upstream) that affect fuelling.

4 everyone fits induction kits. its gives you a better sound and slightly improved performance. fitting one will not affect the ecu it will run as it did before but you will have better airflow and cooler air at that. the better type to go for is one that has pipe work going into the inner wing by the near side front wheel. the best one on the market is the itg filter but very expensive , around £350.

5 the oil catch tank is certainly the best starting point. other than that the next best thing to do is keep the air filter clean to stop any dirt getting through and jamming the valves.

[Dan1971]

I've just fitted a decat.

Engine light didn't come on initially ..... But ... It's on now. I'm not bothered to be honest. In my normal driving position, the light is obscured by my steering wheel anyway.

Massive difference in the mid-range, coupled with my induction kit, (Pipercross Viper - Ebay £125), 2nd revving nicely to just over 60mph and the additional noise isn't too intrusive.

Great mod. :thumbsup:

[stamford]

Dirty air does not affect the vis motors, it is oil ingress that does that and messes the motors up. The best way to look after the vis motors is to remove them, beef up all soldered joints where necessary. If careful you can bolt the micro switches down using M2 bolts and nuts but be careful when drillng through and fixing so as not to damage or short out the pcb tracks. Both vis units are of poor design and quality hence the issues. Oil catch tanks do minimise the amount of oil recirculated which finds its way inside these units via the breather in the base of each moulding.

KevG was offering MIL kits, pm him in case he is still doing them, other than that it'll be PTP as mentioned. As said some don't suffer the light comong on, some do, mine took a couple of months and is on/off like a light switch at times.

The standard Siemens ecu has a limited ability to 'learn' basic mods, it can't advance the timing but can retard it, it can also change the fuelling by a small amount to cater for varying weather conditions etc. To go beyond this you'll need a remap which on average may give another 10bhp on top.

[Spannermonkey]

Thankyou Gentlemen, very much appreciated, will de-cat this weekend with ind.kit and HOPEFULLY the bloody light will stay off.

by the way, what does the MIL kit do, and where does it go? if i have to get one, want to be able to fit it myself.

Cheers!!:thankyou:

[Jay-ZS+]

Its a few wire with a couple of resistors I believe, tricks the sensor in to thinking the emmissions are the same as with a cat, easy to fit if you happy to get under it and cut/splice a few wires :)

[Spannermonkey]

Brill! where do I get the MIL thingy from, or do I have to make one??

Thanks for the info, mate. Looks like you are pretty close to me too, I work in Bristol, and see quite a few ZS's on the way to and from work, I'm in a LeMans green ZS180, lowered with "180" on the wings, and a "funny " number plate, gissa toot if you see me!!

Mike.

[KevG]

it is easy to make one.

What you need are:

Wire (Black, Red, Blue) about 0.75mm in size
a resistor to the value of 1Meg Ohm with a tolerance of +/- 5%
a 35v, 1uf tantalum capacitor (Resin dipped are good)
some butt splices (Crimps)
wiring info http://www.ptp-ltd.co.uk/inc/0009/downloads/MIL_Eliminator_Instructions.pdf

or you can just buy it from PTP http://www.ptp-ltd.co.uk/shop/258_55/mg_rover/mg_zs__rover_45/exhaust_systems/mil_eliminator_%28malfunction_indicator_lampcheck_ engine_light%29.htm and get ripped off, or make it for £10

How it works

The Mil eliminator is just a few capacitors and resistors and is installed in the wiring of the second
sensor.
If you remove the cat and change nothing else then the send sensor starts to show exactly the
same signal as the first one (BTW only the first once is used to adjust the mixture). This is
detected by the ECU (under some specific circumstances) and it can trigger the MIL.
The processes inside the cat will store and release oxygen, just like a capacitor stores and
releases electric charge. If you look at the signal from the second sensor with the cat installed
you’ll see a gentle rise and fall of the voltage as you press and release the throttle.
What the Mil-eliminator does, without the cat is take the signal from the second sensor (which is
now a ½ to 1 Hz signal alternating between 0 and 1V just like the first sensor) and ‘smoothing’ it
out.
The charging and discharging effect of the capacitor on the signal sent to the ECU look
roughly the same as the signal the sensor produces when a cat is present and is hopefully
enough to fool the ECU in thinking a cat is present.

[Dan1971]

it is easy to make one.

What you need are:

Wire (Black, Red, Blue) about 0.75mm in size
a resistor to the value of 1Meg Ohm with a tolerance of +/- 5%
a 35v, 1uf tantalum capacitor (Resin dipped are good)
some butt splices (Crimps)
wiring info http://www.ptp-ltd.co.uk/inc/0009/downloads/MIL_Eliminator_Instructions.pdf

or you can just buy it from PTP http://www.ptp-ltd.co.uk/shop/258_55/mg_rover/mg_zs__rover_45/exhaust_systems/mil_eliminator_%28malfunction_indicator_lampcheck_ engine_light%29.htm and get ripped off, or make it for £10

How it works

The Mil eliminator is just a few capacitors and resistors and is installed in the wiring of the second
sensor.
If you remove the cat and change nothing else then the send sensor starts to show exactly the
same signal as the first one (BTW only the first once is used to adjust the mixture). This is
detected by the ECU (under some specific circumstances) and it can trigger the MIL.
The processes inside the cat will store and release oxygen, just like a capacitor stores and
releases electric charge. If you look at the signal from the second sensor with the cat installed
you’ll see a gentle rise and fall of the voltage as you press and release the throttle.
What the Mil-eliminator does, without the cat is take the signal from the second sensor (which is
now a ½ to 1 Hz signal alternating between 0 and 1V just like the first sensor) and ‘smoothing’ it
out.
The charging and discharging effect of the capacitor on the signal sent to the ECU look
roughly the same as the signal the sensor produces when a cat is present and is hopefully
enough to fool the ECU in thinking a cat is present.

:rofl:

I don't undertand any of that ! Hats off to you young sir and your knowledge.

:rofl:

Still. Each to their own eh !

[Jay-ZS+]

Brill! where do I get the MIL thingy from, or do I have to make one??

Thanks for the info, mate. Looks like you are pretty close to me too, I work in Bristol, and see quite a few ZS's on the way to and from work, I'm in a LeMans green ZS180, lowered with "180" on the wings, and a "funny " number plate, gissa toot if you see me!!

Mike.

Will do, Hopefully soon you will be able to spot mine a mile off, you will know what I mean if we pass each other :) ;)

[Spannermonkey]

Mr KevG,
you are a clever ******!!!

Thanks.:yes: