Wide band gauge.

[j-f]

I was thinking that it could be a good investment to buy a air/fuel ratio gauge to tune engines. I have a few friends that have built engines but none are really tune up correctly. They ran, but as this.

Do you think it could be helpful to have a such device to tune our engines ?

I also found one that centralize lot's of stuff in one gauge. Ok, it's not old school, but I don't like to have too much gauges in my dash board. On the other hand, It only allow to check one things at a time.

http://plxdevices.com/product_info.php?id=MULTDM6
http://cbperformance.com/pdf/PLX%20DM-6.pdf

[Sam K]

I use an Innovate brand wideband that does data logging in my cars and I've been very happy with it.

[brian e]

http://www.summitracing.com/parts/AVM-30-5130/

This is the one I got.  Made a huge difference and showed me I was way off on my jetting when I thought I was close.  It made my first engine with kadrons go from, >20mpg to an easy 29mpg and run way better.  On my last 2276 I slowly went from 15mpg baseline to 26 as I got it closer to tuned.  It shows lean transitions, progression spots, and cruising ratios perfect.  The good thing about the AEM is replacement sensors and harness' are really cheap.  I don't data log with it, but it does have a 5v output if you want to run it with an EFI setup. 

I would recommend mounting it and a small tach (if you don't already have one) in a small plastic radio shack "project box"  and then it will be more of a temporary mount.  You could run it out from under the rear seat and leave it between the shifter and brake handle on a loose harness.  After a week or two of playing with jetting, the car will be tuned, and you can pull the gauge and rent it too your buddies. 

Brian