What Co% setting?

[Fraggle]

Hi

I am running a 1600 twinport with twin 34ICT's and a 009 dizzy with extractor exhaust.

Does anyone know what figure Co% I should be aiming for? Or what is too much or too low?

Cheers :winking0060:

 

[bugger]

below 4.5 :innocent0001: well that was on the tester for an mot

 

[froggy]

below 4.5 :innocent0001: well that was on the tester for an mot

Didn't think they analysed older cars, thought it was just a smoke issue (x parts per million) that they tested against because we dont have cats fitted?

 

[bugger]

below 4.5 :innocent0001: well that was on the tester for an mot

Didn't think they analysed older cars, thought it was just a smoke issue (x parts per million) that they tested against because we dont have cats fitted?

Funnily enough i was thinking that after i had posted,but for anything over 1975 then the test does come into play,i had my t25 done on monday for buyer to pick up friday,then it is forward and upwards in my 71 when its finished

 

[Loxy]

below 4.5 :innocent0001: well that was on the tester for an mot

Didn't think they analysed older cars, thought it was just a smoke issue (x parts per million) that they tested against because we dont have cats fitted?

Funnily enough i was thinking that after i had posted,but for anything over 1975 then the test does come into play,i had my t25 done on monday for buyer to pick up friday,then it is forward and upwards in my 71 when its finished

The Haynes manual tells you the stock setting, will have a look tonight unless someone can get to one earlier (iirc 2-2.5% rings a bell - but dont rely on that until its been checked :lol: )

 

[Haveacamper]

i dont think they test it for an MOT then just look to see if there is any smoke from the exhaust.

having said that i believe checking the percentage helps set up the engine

 

[froggy]

The Co2 set up will help the engine run better as you can tell whether its to rich or to lean , but you will need an analyser to do this correctly.
Remember reading on VZi about making your own analyser using a lambda sensor but this needs drilling to fit into the exhaust then connecting to a volt meter.
TBH if the carbs are set up correctly (and balanced) then you wont have have an issue with the Co2 readings

 

[Fraggle]

Cheers guys

I have an analyser now just wanted to kinow what to aim for.

 

[Loxy]

Cheers guys

I have an analyser now just wanted to kinow what to aim for.

Sorry buddy forgot to check last night, pm me this evening & I will check the manual.

 

[Pete B]

Just had a look in Haynes, only lists Co for '75 on, and that is 1.00 to 3.00%. As someone else suggested, I would aim for about 2 to 2.5% , thats a nice sort of figure for any engine of that era, not just VW's. (if my memory serves) You could try contacting Pete Nice, he knows his stuff. Regardless of the mot, checking the Co will tell you if the mixture is set correctly. Too lean and combustion temps go up, too rich and you risk washing the bores. And it can be a fair way out without being blatantly obvious.

 

[Loxy]

Bentley says 3% +/-1% at idle for 34PICT3.