AFR readings

AliK

AliK

Vehicle Dating Officer
Staff member
Club Member
As with all things old school, here's a subject I thought I knew something about but as I read up I realise how little I really know!!!

So gang, my new obsession de jour is carb tuning and AFR. What do those who monitor such things consider to be an acceptable range!? I've put together the table below from a website I was surfing with great info, but wondering what the Z world experienced heads say - clearly it has a lot to do with specific set up but do these definitions seem about right!?

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(Note: I want a clean fight, no punches below the belt, if the other party goes limp or taps out, it's over!)
 
Ali

Does it not depend on the type of carbs you are using i.e. SU, Hitachi, Weber etc.?

As you know, I don't go in for all that fancy gadgetry or stats when I am tuning my twin SUs. I just tune it by ear (although I have now found that using my hands is better EXTRA:D) and try to achieve the smoothest throttle & idle whatever ratio that may be, through small adjustments on the fast idle screw and mixture. Takes a little time and patience but I have gotten mine running silk-like using that method. Not for the purists I know.
 
For WOT I'd be happy if I can get > 12 < 13. But actually 3-4k rpm it dips into the 11s, injection is going to be the answer to that.

For cruisin', > 13 < 15
 
What afr are you using jon as I am using an Inovate but my lambda sensor has packed up .
 
On my silver ratty car that now how the FI removed and back to SU's, I've been playing about with AFR's. I'm using an innovate portable AFR gauge/data logger. From my experience you cant run carb as close to Stoich as FI. Richening up a little (mid 13's) has improved acceleration and general response. I get mid 16's on cruising which is nice. Down to low 13's on hard acceleration but 12's on tickover which is the only bad point.

That chart is great.
 
johnymd said:
On my silver ratty car that now how the FI removed and back to SU's, I've been playing about with AFR's. I'm using an innovate portable AFR gauge/data logger. From my experience you cant run carb as close to Stoich as FI. Richening up a little (mid 13's) has improved acceleration and general response. I get mid 16's on cruising which is nice. Down to low 13's on hard acceleration but 12's on tickover which is the only bad point.

That chart is great.
Click to expand...

Thanks Johnny.

This is very interesting info you've shared. Do you have a link to your AFR gauge?

Also are you running Vac advance at idle?
 
Just ordered a lambda sensor from China should be interesting to see when it comes
 
Well it was cheap, I got one for 2.62 and 82 pence for postage but they must have put the correct price on it now
 
Why are these LSU4.9 sensors so cheap? The normal retail price is around £120.

Both my sensors are the old L2H2 which were even more expensive.
 
There's a lot of normal diesel road cars have lsu 4.9 sensors these days so the market got bigger. The last 2 I bought were genuine bosch and they were still only about £45.
 
jonbills said:
There's a lot of normal diesel road cars have lsu 4.9 sensors these days so the market got bigger. The last 2 I bought were genuine bosch and they were still only about £45.
Click to expand...
That was good price for genuine bosch, how long did they last ?
 
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