jamesjones

I finally got round to having the emissions checked after fitting my Scoobysport Downpipe last week. I promised I would post both sets of results and so I am.

Car is a MY99 with ITG air filter, Scoobysport BB and DP. No other mods (e.g. original mid section with CAT and no boost controllers etc). Car has only done 15k miles from new.

The first test was done with the original CAT DP and the second test was with the decatted SS DP, just 278 miles later. Both with Super UL.

For the second test I drove around for 5 minutes and then straight in. I don't know if the car was warmed up for the first test. Nothing was done to influence the test. It was exactly how the MOT tester is supposed to do it.

FIRST TEST (with original DP cat)
Fast Idle test
Engine speed - 2762rpm (2500 to 3000rpm)
CO level - 0.16% (- to 0.30)
HC level - 17ppm (- to 200)
Lambda - 1.00 (0.97 to 1.03)
Natural Idle test
Engine speed - 807rpm (450 to 1500)
CO level - 0.47% (- to 0.50)

SECOND TEST (with SS DP decat)
Fast Idle test
Engine speed - 2862rpm (2500 to 3000rpm)
CO level - 0.07% (- to 0.30)
HC level - 7ppm (- to 200)
Lambda - 1.01 (0.97 to 1.03)
Natural Idle test
Engine speed - 794rpm (450 to 1500)
CO level - 0.26% (- to 0.50)

As you can see it performed better with the Cat removed than it did with it on.

Disclaimer (type thingy) : Every car is different and the quality of the mid CAT will vary but my car passed easily with the front one removed, so there is hope for probably most of you who are thinking of removing the CAT.

Hope this clears any lingering doubts for those who are deciding on whether to do it or not. The chances are that it'll pass especially if the car has been well maintain and warmed up before the test. Pete at Scoobysport told me it will and he was right. Thanks Pete.

J


[Edited by jamesjones - 7/4/2002 9:05:27 PM]

JamieMacdonald

This is all very encouraging! I think I feel a SS DP on it's way (was going to get one anyway ).

Cheers James!

Jamie

[Edited by JamieMacdonald - 7/5/2002 6:11:14 AM]

Dark Blue Mark

Interesting....!

I have the same setup on my MY99.

MB

RON

Very!!! interesting that is, we might not need to bother with the twin catted centre then mark!!, you going monday?

LeonWells

mmmmm Very interesting! so it is a better option to change the downpipe and retain the mid section cat rather than changing the mid for a decat and keeping the OE downpipe?

If so il get one! has anyone else used this configuration and passed the MOT? i thought the cat at the front was the bigger of the two and the mid section cat was just a cold start cat?

jamesjones

Leon

I'm not sure the removal of the front CAT will be better than the mid one in terms of emissions. It certainley is in terms of power.

I did think my results might take some revenue away from Scoobysport with less people renting their twin cat centre, but it looks like I could be pushing people into buying their DP's (not that they need it).

J

P.S.
Perhaps people can post before/after emission tests for different exhuast setups (and makes).

SPEN555

James,

Thumbs up for posting this as I am always seeing discussions on here about whether the centre section has a cat or not and whether it can pass an MOT with just the centre.

You have now given me the confidence to try and pass the MOT with just the centre section when it becomes due.

Damian.

nom

Just one thing - a variable was different between the two as far as I can tell (was mentioned but not very clearly!) - with the first test, the car hadn't been driven round before, therefore the DP cat would have been cold (and the mid) and so will have higher emissions. I suspect if the car had been driven round for 5 minutes with the DP fitted it would have got 'much better marks'.
However, it doesn't really matter 'cos it passed on the mid-section anyway

Pete Croney

Hi James

No worries about our twin business M8, its only really needed for the older/high mileage cars.

Glad you have put the figures up, as some many people ask this.

Dark Blue Mark

Ron,

Maybe not!

Will give the meet a miss...

MB

steve McCulloch

It does aannoy me somewhat this emissions nonsense

All I'm gonna do is put the original exhuast back on for the test then put my Scoobysport/HKS exhaust straight back - in fact the garage may do both - it would be better if they just passed me! anyway... what a nonsense.....

RB5-Black

good info

I can sleep better now, DP getting fitted on tuesday

john banks

How best to store the centre cat to preserve its useful life when "not in use" ? Mine sits in the attic.

Brun

What co an hc levels etc. would be a mot fail?

jamesjones

The figures in brackets are the min and max values that are required. As you can see they were well within for my car. Lets hope they are for the rest of you lot.

Edited to say that if just one falls outside, the MOT fails.

J

[Edited by jamesjones - 7/6/2002 9:14:37 AM]

jamesjones

All
Let me know how you get on with the MOT's without your front CAT.
J

motomc1

thats good to her will just put the mid cat back on for the m.o.t then and see what happens..

PeterPerfect

Thanks for posting this information James
I'm considering the same exhaust configuration at the moment.....
Pete