Corvette Forum : DigitalCorvettes.com Corvette Forums banner
1 - 5 of 5 Posts

·
Registered
Joined
·
371 Posts
Discussion Starter · #1 ·
I have the opportunity to borrow a friends LM-1 AF meter to do some tuning and am just waiting to get a bung welded into my header to allow for us to run with the laptop to get a good picture of what is going on.

My friend that is going to weld the bung for me scoffed a little and said if she runs well when you floor it and the plugs look ok then thats all you need.
He also made the following comment which un nerved me a little...

If the AF meter tells you that you are running slightly rich and you drop a jet size or two, what happens to perhaps the one or two cylinders that could already be running lean? The intake will not be delivering equal amounts of fuel/air to all cylinders and your reading will be a guess at best of only four of the eight cylinders.

I thought about this but my argument is that the intake fuel delivery difference would only be minor and that the meter would give an accurate real time reading of what was going on. I also like technology and gadgets!
Unless a spark plug is oil fouled or busted up...Im sorry to say they all look much the same to me So I would need to pull them and post pics to get a proper reading.

Having a bad back sucks...makes me think about all these dumb questions I can bug you all with...sorry :spanked:
 

·
Registered
Joined
·
1,196 Posts
I tune with a LM-1. I have two bungs, one in each header and sometimes move the sensor but find the readings the same side to side.
I also ran 4 temperature probes and found my front cylinder running 158 degrees hotter then the other 3 behind it. This is the plug I always check on spot checking.
I believe in the meter. You set the idle for about 13-14, closer to 14 if the motor continues to idle well. This is also your cruising ratio. If you set the idle by feel alone you could be idling at 12-1, good idle but tooo rich and this becomes your cruising mixture.
How do you check main jets???? Cruising and then pull over and check a plug????
I drop down into 4th and bring the rpm to 3000 or better and read the meter. If it is about 13.8 I am good. I jet accordingly to bring it in that range.
Wide open????
Again drop it down a gear or two and punch it and take a reading. You are looking for about 12.5 No plug reading will help you there either.

No if you get a chance use the meter and set it up for maximum economy and yet maximum power under WOT.
You can set it both ways. 13.8-14 for cruising and idle and 12.5-13 for WOT.

NO plug reading will tell you exactly what you are running.]
Pulling plugs can give you and indication, and that includes timing by reading the center electrode but for actual tuning go with the meter.
 

·
Registered
Joined
·
40 Posts
The LM1 is a fantastic tuning tool as strider points out . I have bungs in both pipes to facilitate tuning . You won't be disappointed with your results, with fuel prices these days every little bit counts ,,,,,,,,,,,,,,,


G
 

·
Registered
Joined
·
636 Posts
Been monitoring my '84 lately, and looking forward to getting the '69 on the road again. Lots of good info in a short amount of time. I should have bought one of these a long time ago.
 
1 - 5 of 5 Posts
Top