Pussy Cat

[CAMSHAFT]

is there any pro`s or con`s to removing the cat in a yaris, i know this will effect the o2 sensor so the engine managment light will display on the dash, is the any power gain if only small reached by doing the and will it also increase noise for the car, any ideas

[seveer unaek]

Noise will be much increased! But the main pro of a de-cat is that the exhaust will be one long smooth shaft (beautiful) and will therefore get the nastys out of the car quicker, therfore increasing performance. Dunno how much tho!

[Crisis]

Also means your car will fail the MOT.

[Yaris WRC]

15 min gets the cat back in for about 15 quid at an exhaust place. i would gladly pay that every year. CATS suck big time.

if you want performance take it out.

[RFvitz]

is this easy to do?

[Viper_7]

Coppers these days are equipped with mobile emission testers. If you get stopped and tested....well.... hefty fine and points, and as said it will fail the MOT not just because of the emmissions ( which may still be within limits) but because the CAT's been removed.

Insurance wise as well.... if your in an accident...your car will be checked...and will be found to be illegal, hence insurance wil lbe void.

Also you'll be reducing back pressure...which isn't always good on a performance car.....but sod all to worry about with what we have to work with.

All negative...but you need to know the cons...as well as the pro's.

but aye...responsivness is much better and you'll gain a few bhp quite easily.

Vipes

[yaristpot]

I feel good gains from mine being in the bin... the only down point is that the management is on 24/7 and theres no way of seeing if there is any other problems that may be happening...

[minnnt_ts]

yo tpot read drb5's post about it entitled for the attention of any1...

Minnnt

[yaristpot]

ta but i can read my engine codes..... ;)

[drb5]

Simple to rectify this problem, if you can get a hold of a 2 poster!

[Ryan1985]

He works 4 Toyota drb5!

[drb5]

Ah cushty!

[yaristpot]

He works 4 Toyota drb5!

SHHHHHHHHHHH!

[CAMSHAFT]

a few things:pro`s

1. here in ireland our MOT is called a NCT and its justs passed its test for 2 year so i`ve 2 years before i`ve to worry about the test.

2.irish cops equipped with mobile emission testers,eaa don`t think so

3.i have open Insurance so it does`nt matter if the car is modified or not

4.we have a 4 poster at work

con`s

:( 1. engine man. light on the whole time

so i think i`ll do it, i`ll take a few pic`s as i do it should be easy enough

[s0cks]

Why does no-one listen to me! If the engine managemnet light is on its NOT a good thing. Its NOT just telling you something is wrong, it means the ECU has reduced the power of the car to stop as much damage as possible.

You add an induction kit and exhaust system, the ECU will learn and push 18 to 20% more fuel through. You take the CAT out and have the engine light on it'll reduce throughput.

So I can't see how anyone with a de-cat is feeling gains, and if they can feel a gain its unlikely to be anywhere near as much of a gain as if the lambda sensors were wired up.

Just so you know all the cons

[CAMSHAFT]

if thats the case socks then its far better to leave it in.true?

[knightrider]

the car is very smart and will probably realise the cat is missing and run in limp home mode

[Yaris WRC]

i would beg to differ.

i had an air fuel ratio meter hooked up to mine and its running rich with the cat out.

[s0cks]

The ECU is smart... its not like it used to be on older cars. Hook up a laptop to your Yaris and you will see erroneous readings.

[CAMSHAFT]

i don`t know what to do not, i`ll think i`ll leave it in

[breezer]

be on the safe side

[knightrider]

nick did have all the sensors back in?

did the engine light come on

[yaristpot]

Im the same as nick... no cat... second probe in, light on and running rich at the top end.... this may go on and on!

[SuperRetard]

Well, when I plugged the lappy into Nizan's car (decat) it was running on an open-loop permanently and was running a fixed fuel map and ignition map. There was a 0% change in the curves and over a 1/2 mile straight it was about 2mph and a second faster than my 1.3!

If that isn't decreased performance, I don't know what is.

I think the open-loop map is what normally gets used when your lambda sensor isn't warm yet, hence it's aimed at cold-running so it's a rich mixture. I don't know whether it's giving you any more performance, but to get the real benefit with the VVTi engine, you may need to fit a high-flow sports-cat with the lambda sensors back in - or get a new piggy back ECU to take full advantage of the de-cat.

EDIT: Just read that you guys have put the sensors back in with no cat, and there's no problems. I've been wondering what would happen - I bet the redlight is just showing an error code for a dead cat! I dunno whether it's running a closed loop tuning map again tho'...

[yaristpot]

exactly, two sensors... one before and one after reading, the ecu has picked up theres no difference and is questioning the cat... thats not going to put it in limp home mode in my eyes....

ok.... question....

We all know toyotas use the second trip logic system dont we... so when you remove the code and dont get it back for 2 trips why is the power the same and when the light comes back on there is no drop in power of performance???