Is there an affordable unit out there? It seems that for someone who didn't want to spend a fortune on a dyno or rent a dyno by the hour it would be the next best thing for precise tuning. I've found 2 companies that make them but they get $900 - $1800/plug. All they are are modified stock plugs.

OEMs use them for tuning. Or at the very least they use transducers with ports drilled into the combustion cylinders to detect cylinder pressure.

I'm not a race car type guy. My rig is a rock buggy with huge knobby tires. Even if I had the desire to spend a lot of money at the dyno the results wouldn't be that accurate through the 47" rubber. I could throw some stock tires on the back wheels for temporary use but even then the results would be questionable through all the extra gearing I have. (3:1 t-case, 6.72 axle ratio.) To me it seems that if there was an affordable way to detect cylinder pressure it would be more worth my while to buy that and spend some time on an abandoned road with my tuning software and laptop. I'm running a stock LS2 for now but am trying to learn to tune a more modified engine in the future.

J. J.

 

It can be done with a wideband on the street/track. I do some cars that way... I've tuned hundreds of LS cars/trucks and know where the timing should be based on dyno experience for different combinations. The wideband gives the fueling feedback you need. At the track, comparing timeslips will help you fine tune it. On the street, stay on the conservative side...

I have a customer with a 66' Mustang roadrace car with an LS7 in it that I am going to be tuning like that in the next week or so...

 

I appreciate your feedback. I know it is possible to do on a track and that is what I plan to do eventually. Unfortunately I do not have the experience that you have and am just starting out. I do know that max torque directly correllates to max cylinder pressure before detonation and that no matter what kind of testing you're doing, dyno or track, essentially what you are striving for is max cyl pressure without the benefit of directly measuring it. OEMs measure cylinder pressure directly as one of the most vital pieces of info in their arsenal. It would be really cool and useful to be able to do the same.

Eeking every hp out of my engine isn't even my objective. Even if I were to find an extremely accurate point of cyl pressure I would definitely back off it just to be safe. For what I'm doing peak performance isn't as important as durability and longevity. I could just send my ECM off to a tuner and let someone else do it and probably never regret it. But I'm a gear-head at heart and want to know / learn these things as oppossed to just do them. I'm judging by the lack of response thus far that no one knows of an affordable pressure sensing spark plug?

J. J.