Andy W
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| posted on 18/7/04 at 05:36 PM |
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Revs for CAT test
Took my car for MOT yesterday to try emmisions. I've got a '98 zx9 engine. The exhaust has a cat from a fiesta in it. I fitted some
pneumatic air regulats to the vacuum gauge connections to give me adjustment. At low revs everythong seemed fine but the lamda was out. I bled air
into the engine but this made it worse, which seems to mean a may have an air leak, but I can't see anything obvious. When we tried at 4000 rpm
I got a pass on everything. My mate who did the test said this should be ok as you can go to half max revs. Just wondering what revs other people have
had on SVA. Also I read in one of the links that you may be able to increase the lamda by restricting the exhaust outlet to hold the gas/air in longer
can anyone confirm this.
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alister667
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| posted on 18/7/04 at 09:37 PM |
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My SVA emmisions test took place after you hold the car between 2500 and 3000 rpm for about 30 seconds. Then they take the reading for the last 5
seconds. If that fails you can repeat the test holding the revs at the same range for 3 minutes.
As you hold the revs at in around 3000 rpm you should find the Lambda reading should drop to the pass zone (0.97-1.03).
Good Luck.
Ali
http://members.lycos.co.uk/alister667/
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Jasper
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| posted on 19/7/04 at 09:37 AM |
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Good luck - and welcome to the hell that is getting a ZX9 from SVA emissions
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Mk-Ninja
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| posted on 19/7/04 at 09:56 AM |
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The lambda sensor is sensing unburnt oxygen, so as you say any leaks in your exhaust sucks in air and throws the reading out no matter what you do
with the carbs. So for starters make sure you have no leaks, I sealed all the joints on the system with silicone sealent, it smokes a mit before its
fully cured but seam (amasingly) to stand the heat, even of red hot headers.
Only when you have the system sealed should you start adjusting anything. The ploy with the air bleed system is to get the carbs running rich and then
lean it down with the air bleed, but it is a bit of a balancing act. Good luck, hope you get it sorted. Keep us informed on your progress and dont get
disheartened, It will pass.
I'm sure I've got one, just don't know where I've put it
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spunky
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| posted on 19/7/04 at 10:12 AM |
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Andy,
SVA emissions is carried out at 'fast idle' for a car, ie between 2.5 and 3k. This is a joke on a ZX9 but the test doesn't allow for
bike engines. At tickover you only have to worry about CO and HC not Lambda
You have my sympathy, but as stated, dont give up, it can be done. Even on EFI twins   
Good luck
John
John
The reckless man may not live as long......
But the cautious man does not live at all.....
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sting
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| posted on 19/7/04 at 12:32 PM |
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won`t be getting SVA`d till the end of this year but is the lambda measured by the sva centre or do you have to fit a sensor to the manifold. If so
how do you wire it up as the zx9 has no loom connections?
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Mk-Ninja
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| posted on 19/7/04 at 01:52 PM |
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The SVA have there sensor to test the emisions. If you fit a cat kit to sort you emisions out then you need to fit a lambda sensor to the exhaust (
this comes as part of the kit if you hire it) the only connection to the electrics is a 12v feed from the ignition which powers the seperate ECU and
vacuum guages.
But what some people are doing (as per snoopys thread) is to use manual bleads into the vacuum ports on the inlet, and balancing it with the mixture
screws to get the desired effect at a specific rpm, you still need a cat but not the full kit.
I'm sure I've got one, just don't know where I've put it
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Andy W
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| posted on 19/7/04 at 09:28 PM |
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I rang Beverley today they confirmed that the test will be at 2500 - 3000 rpm. The guy on the phone said if I went up to 4000 rpm I would wee the
lamda test. Which I did on saturday. He said this rpm was used because it would be the rev range that the car was mostly in (who's he trying to
kid). Anyway I checked the air screws and there at 2 3/4 turns out, so I might turn them in a 1/4. Also made a new baffle for the exhaust as I had a
reading of 110db. I'll try again on saturday see if things improve, then Beverley next week.
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alister667
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| posted on 24/7/04 at 12:22 PM |
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Something easy to do to reduce the noise reading is to stick 1 or 2 of those stainless steel scouring pads (the ones without soap in them!) up the
silencer (on the manifold side before fitting so it doesn't blow out).
This can knock quite a bit off the sound readings.
If that's not enough fitting some acoustic foam under the bonnet can knock a further 5dB off as well.
I used both and got down to 96dB (I think I recall).
Good Luck
http://members.lycos.co.uk/alister667/
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