AMBurnsy

Mike_RT4: I have had a pipe welded in both sides to bypass the back box unit. Its around 25-30mm I think. I can get some pics up at some point but wont be anytime soon.

KW_21: Been advised by the "Garage R" company that a decat on a 1999 is pointless and they don't do them anymore?

Mike RT4

You won't notice any difference at idle, it only gets more vocal at wide open throttle, but it doesn't become really noticable until the de-cat is fitted and then even blips of the throttle (with the roof down) and you can detect a more fruity sound.

Er, then I would suggest that this Garage R company do not have a clue about this car, as the earlier cars ran even richer than the later ones, so fitting a de-cat / K&N induction will lean the fuelling off to a nicer level as well as releasing 6-12bhp (depending if you do one or both together).

My car is a 2005 and even that jumped 6bnp with just a de-cat:


Forgetting the power improvement, it sounds lovely with the exhaust mod .

AMBurnsy

Thanks for that Mike, nice to see evidence for it too.
I want a decat that wont bring up lambda sensor errors or any red engine lights. Any recommendations?

lukeyboi89

+1 looking for a decat with o2 spacer so theres no EML light?

also is there a conclusion on the best diameter pipe for the uk mod?

cheers

Bodyboarder1981

I've had my resonated decat fitted with the spacer on for around 600 miles ... no light yet . Also have the exhaust mod done with 38mm and it's perfect imo.... subtle yet noticeable.

Mike RT4

The light WILL come on even with the CEL delete extension, but it is pretty random as to when it does (usually after some light throttle cruising).

However, it is easily rectified if you purchase one of the OBD readers off eBay (£11-13) and then one of the software programs for your phone (such as OBD Fusion), you can then read and clear the codes as and when for under £20 all in, and it will also allow you to trouble-shoot other cars with an OBD port as well (I have the same issue with the Supersprint race CATs on the CSL, so just clear the code on that as well when it comes on). The code that you WANT to see is "P0420 Catalyst System Efficiency is below threshold". Basically all that means is that because you have de-cat pipe the measured lambda figures from the pre-cat to the post-cat sensors are not showing a suitable deviation that the ECU is expecting to see, so it trips the CEL warning.

Obviously if you get a different code, then you should investigate accordingly, but is a great tool to have.

kw_21

I've had a Berk Test Pipe on for the last two years with no CEL light since fitting. One of the cheapest and best mods you can fit for me

Irish TuneR

Yup had the Japspeed resonated decat for years with CEL extension and never had an issue. Maybe your extension isn't long enough and size does matter...

Mike RT4

Seeing as both your cars that haven't had the lights come on are pre-facelift, it could be that the ECU is not as sensitive to these deviations, especially as the early cars ran very rich from the factory anyway ? I can go 5-6 tanks without it tripping and then randomly it comes on (usually a short while after restarting the car after a light cruising run).

I can only comment as I have found with a MY2005 car.

​​​​​​​You can see the size of mine on post 15 .

lukeyboi89

anyone have one of the above mentioned decat pipes for sale?