Air/Fuel Ratio Gauge/Meter Invaluable for Tuning (IMHO!)

Hudson_in_Seattle

hey guys - i finally replaced the power adaptor for my Innovate LM-1 air/fuel ratio gauge to obtain mixture results for my '53 hornet twin-h

the old Innovate Lm-1 is read in the car and uses an O2 sensor attached with an optional exhaust clamp to provide air fuel #'s while driving, in order to get data under various real world driving conditions, i.e., at idle, under various loads, uphill, wide open throttle - (image attached)

today's units still use an O2 sensor, smaller, use app's on smart phones, store/show data differently, etc

i used this unit on my classic cars to set idle mixture, to check mixture while driving as above, especially looking for any lean running issues - i don't use any data download functions - i have found this to be an invaluable tool!

late last night, i obtained idle mixture results: while adjusting the carbs, after changing distributor advance, while driving up long steep hills/grades, when accelerating from a stop onto the freeway, when accelerating from between different higher speeds on the freeway, etc.

as a result, i could see the settings were pretty good, but much better mixture ratio's/drivability after some minor changes, and added confidence added for potential lean running issues

hope this info is helpful

TwinSupercharged

what were some of your results on your real driving?

Hudson_in_Seattle

thanks - my hornet has a wildrick built 308, '56 block, larger intake, wildrick head, more cam/compression, headers into single 2.5" exhaust and hydramatic

- i'm at sea level here in seattle

- my initial idle mixture was 13.5:1 so i richened up to 12.5:1 - all readings were surprising smooth and adjusted well to changes throughout - in nearly all conditions, the mixture varied from 11:1 to 13.5:1 staying mainly in the mid 12:1 range

- at highway speeds accelerating with slight throttle from 55 to 65, the mixture leaned to nearly 15:1 and felt a bit surgy - (at high speeds turbulent air screws up readings with the exhaust mount) - i reduced the total timing advance sequentially, and at about 6 degrees total advance nothing leaner than 14.5:1 under the slight throttle condition with the remainder in the mid 12:1 range

- if i had webers, i would know how to richen the top range w/jets and w/o changing timing - i'm still figuring out the carters, which run so well, i'm not inclined to mess with them

 - hope this helps

StepUp

Great info above ---thanks for posting!

Optimal A/F ratios on performance Chev V8's are:

14.5 -15 IDLE

14 -15.5 CRUISE

12.7-13.2 WOT

What A/F ranges we should target on our Hudson I6s?

Anyone here with an I6 + EFI might shed some light on the answer. Any Hamilton EFIs users here?

dave11

What are these units selling for?

Hudson_in_Seattle

regarding air/fuel mixtures, look online/get info from pros - conventional wisdom is do not run too lean, especially for any length of time - if you hear pinging/detonating, that's engine damage - whether it's too much advance or a carb lean issue, etc., it needs to be addressed immediately

approx 14.7:1 is considered perfect air/fuel ratio, but for cars in real world driving, performance driving, especially older cars, IMHO running richer in the 12.5:1 to 13.5:1 range is much safer for the engine, head/piston temps, etc

i drive my collector cars (when running!) thousands of miles per year - i've had some very bad experiences with burned pistons/heads due to lean running issues - i've tested/tuned dual webers IDF's, dual zenith NDIX's, bosch MFI, CIS FI, D-Jet FI, and now carter WA-1's, resulting in no problems and lots more confidence when driving these old cars

i bought my old innovate lm-1 used w/ accessories for under $200, but years ago - the image above is from a now active ebay listing at $180 (no affiliation) - the exhaust clamp now runs new for about $80 - the O2 sensor burns out after a while - a new bosch sensor is under $50 - the lm-1 isn't made anymore - new models, either handheld, by gauge or smart phone run in the $200-$400 range - some new models also have 2 O2 sensors for dual exhaust set ups

hope this helps

Glowplug

When this thread started I remembered a YouTube Video that explains this process and where to get the pieces,  hope this adds to the content ... Ken 

https://www.youtube.com/watch?v=YiUDltHKnLE