Hi guys, sorry for the long title - tried to make it as descriptive as possible!

Im after some advice.

Im off to Blueflame next week for a custom exhaust, sports cat and downpipe for my 2002 4x4 Elagance hatch.

Ive been reading over some blueflame related posts on Briskoda and it appears a few people have had their engine light come on on the journey home from Blueflame or very shortly after having the exhaust and cat fitted. My problem is Im over 300 miles away so I cant afford to spot my engine light on when Im pulling back into my drive after the journey back. :(

I discussed this briefly with Nigel at Blueflame yesterday and he mentioned something about the positioning of one of the sensors. He didnt seem sure I wouldnt have the problem which worried me though. He advised that I considered going for a 200 cell sports cat instead of the 100 ultra sports cat - I guess this is more restrictive but sure by how much? Could anyone advise please. I think he was basically suggesting that the 100 cel cat was on the limit of passing emmisions hence why the light may come on with that one fitted.

Also, is it true that the 4x4 has two cats in place as standard?

Cheers,

Lee

100 cel cat can be borderline but so can a 200cel cat.

Yes...positioning of sensor makes a difference....EddyH can explain.

4X4 does have 2 cats...I guess they a 2 smaller ones either side of the prop shaft to rear axle.

The light will only come on when you are driving really gently at a constant speed, I often got it whilst bimbling through the long road works on the M25 at 40. The light can be easily switched off by disconecting the battery for 5 minuites if you dont have vag com. Basically when the exhaust cools it becomes less efficent & the second sensor picks up an emission problem.

Eddy knows the permanent cure, costs about £25 for a little bit to move the sensor.

Reminds me . Eddy you have PM

Just a suggestion chaps, but most'modern' cars these days use 4 wire lamda sensors which have an integral heater circuit which means that they are efficient from the moment the car is started. I'm actually using one on my 30 year old Escort (which is running fuel injection and engine management) and it works a treat. Cost......? Bought one for

If you get the light then there are 2 solutions.

1. Get it switched off by your remapper (assuming you have a remap and they can do it, Custom-Code and Revo S2 can + others I imagine.

2. Fit a spacer on the post cat lambda sensor, you can either make one of these yourself or there is a guy in the US on VWVortex that does them. As Stuart says they work out at around £25. I suppose quite expensive for what it is but they are handmade to a good standard and the guy is doing us a favour by making them. Most importantly they do work!

Thats interesting stuff - so a 200 cel wont necessarily rid me of a problem! :(

Stuart - that sounds like my morning drive each day to work so again, thats not great.

I mentioned to Blueflame about changing the position of the sensor (this was to Ian) and he stated that it shouldnt make any difference what so ever - if its 1 inch away of 6 inches away its still going to detect the same values form the same gases in the same pipe. Is there any more info on this that I could feed back.

The last thing id want is an engine warning light on constantly - surely this could hide another more serious issue if it were ever to happen.

Ian says the standard cats (there are two small ones) are 400 cels so 200 is a fair improvement on that I guess.

Thanks for the input so far guys,

Lee

it's not the distance from the cat it's the distance from the airflow. The post cat sensor is spaced out from the exhaust and at a 90* angle. This seems to allow it to 'see' just the right amount of gas so as not to throw a code either way. Having it turned off in the remap is the best option IMHO though as it's only function is to check emissions.

Cheers Eddy - I posted up at the same time so didnt read your earlier message - thanks for the additional info

Im wondering if Blueflame could do this mod when they do the system?! I will ask them later today and I think I'll take a chance and go for the 100cel cat option.

Cheers guys,

Lee

Just got off the phone to Ian at Blueflame and I read what Eddy said above to him over the phone and he says it makes sense now (not helped by my bad initial translation probably!)

He's going to give the little modification a go next Wednesday when its in for the exhaust. He mentioned something about already stocking lamda extension probes... not sure exactly how that ties in but I belive he has an idea off of what has been suggested here so many thanks guys; particulalrly Eddy.

Im going to go for the 100cel cat and keep my fingers crossed. I'll let you know how the car goes after the exhaust is fitted.

Cheers,

Lee

Stuart will have the extension block tomorrow so if you drop him a PM he might be able to help with a photo. If not I'll try and find the original thread on VWVortex.

Stuart will love me!

Thanks Eddy - any additional info would be great and it may also help other Octavia owners out in future as I'll be taking all this info upto Blueflame on Wednesday.

Lee

Here is a picture of the 4X4's twin cats with heatshields in place. They are circa

Here is a picture of the 4X4's twin cats with heatshields in place. They are circa

Pics!

God you guys are the tops! I hope Im in a position to able to help you guys out in the future!

MANY THANKS,

Lee

just goes to show this website is an invalueable service to most if not all users...