I took the car for a check on the emissions today before my retest on Mon. The exhaust gas was too hot for the probe and kept shutting the system down after 10 or 15 seconds so it was pretty inconclusive.

The question is, what effect does it have to the Co2, HC and Lambda by richening the fuel/air mixture or leaning it?
So if for example he says the HC or Co2 or lambda is to high which way would you adjust the fuelling??

If HC's too high, lean off a bit.
If Co2's too high, no idea what to do.
Not sure what to do lambda, I'm used to old stuff!

you need to look at AFR as well to get the whole picture...

Need it to be around 13-15:1 that should give about the right figures on all with some tweaking..

HC is unburnt fuel, so need to go leaner if these are too high or check cat is working...

CO2 is fully burned fuel, so richer and leaner can reduce, generally richer...

Lambda is an indication of the actual combustion mixture... Cant remember which way it goes...



[Edited on 13/5/06 by G.Man]

Ive reduced the power commander fuel settings by 15% in the test rpm and throttle position. These are the figures that most people have used for the ZX12 it is just that it will probably need fine tuning at the test.
Its always an advantage to know the reasons for what you do.
Does the lambda reduce the faster the engine runs?

Does a power commander allow you to adjust air/fuel easily? - i'm coming up to SVA and i can see that being a big plus point!! Been told by a few biker bods that i should get one but i/m not exactly sure what it does...

A Powercommander allows you to plug in a laptop and play around with all the fuel map points to your hearts content which is obviously the best and easiest way to tweak the emissions, so compared with just a stock ECU where you can't really adjust anything so have to rely more on air bleeds etc, its going to give you a lot more scope for adjustment.

quote:

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Originally posted by ChrisGamlin
A Powercommander allows you to plug in a laptop and play around with all the fuel map points to your hearts content which is obviously the best and easiest way to tweak the emissions, so compared with just a stock ECU where you can't really adjust anything so have to rely more on air bleeds etc, its going to give you a lot more scope for adjustment.

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you need to adjsut the air / fuel ratio to get lambda in the acceptable range of 0.91 to 1.03. Lambda is the excess oxyegen ratio and a lambda of 1.0 means that there is exactly the right amound of air and fuel for complete combustion.

A good cat should convert what is left in your exhaust gasses to CO2. However, engines and cats are not perfect.

If you CO is too high, lean the fuel out a bit. A cat in good condition should sort that out.

I seem to recall that HC emissions are at their lowest with a slightly rich mixture, but I could be wrong.

Make sure the cat is hot just before running the test, they don't work when cold.

I have just been through this getting my F.I R1 Indy through SVA. Base settings gave me zero CO, negligable HC and a lambda of 1.15 ish. I upped the fuel on the power commander on the first three throttle positions 0,2 and 5 I think they are. Started the fuel increase from 0rpm and tailed it off at 4000rpm with the peak at 2500 and 3000. I ended up with values of 10 or 11 at the 2500/3000 rpm point which is the fast idle test point. Also helped that my mate owns an MOT station and has an infra-red temp measuring gun to check that the cat is nice and warm, mine was getting to about 120 degrees.

Thanks for the replies.

So it seems to be

CO if it is to high - lean it off
lambda if it is to high - richen the mixture
HC if it is to high - lean it off

I will see how I get on on Monday

I read on a cat manufacturers web site that a cat needed to be between 250deg and 500deg to operate properly.

Talk to the guy who's built the Spire, he got a ZX12 thro' SVA with a power commander

quote:

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Originally posted by richardR1
I have just been through this getting my F.I R1 Indy through SVA.

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Well i managed to get the engine through the emisions. I used the SVA map that Paul at spire sportscars used on his GT-R, which was -15% at 2000, 2500 and 3000 rpm and from 2 - 40% on the throttle position.

For the first run the figures were miles to high on Co,HC and Lambda. So we leaned it down as low as would go using the manual buttons. Still to high despite the fact that the manifold was now glowing.

Ian, the examiner then said to try it with the tail pipe off which has a restrictor built in to it to reduce noise.

What a difference, Co 0.11, HC 88 and lambda 1.01
and at natural idle the Co was zero.

It is surprising how much a restriction in your tail pipe can make to your emision figures.

The cat in a can that I used with the noise reducer has been used by quite a few others and they have not had any problems with the emision levels and so they have not had to remove the tail pipe. I think it must just be a peculiarity with the ZX12R.