That would definitely be interesting. The output from the AFM could probably be logged by the Trackmate. We'd have to correlate door position to AFM output, but it should be doable. It will be a while before I'm back on the dyno, though. Our AFM's are not upside down.

We are not 911's, either, but then the supply of $500 parts cars would be so good!

XX

Thats funny. Reading one of the links in your sig it says never adjust the spring tension of the AFM. Adjusting the spring tension of the AFM is how I went from 128 to 139 horsepower in less then an hour of dyno time. It's also how I've got dozens of pre-OBD2 cars equiped with AFM's to pass state emission tests.

FR Wilk wrote:

It seems remarkably effective on the dyno.
We don't spend much time at part throttle, so they dyno should reflect track use pretty well
Outside of chip tuning (not Spec) do you have any suggestions FR Wilk?

phlip wrote:

I'm dubious. That's a helova lot of hp increase. Rigorously testing engine management changes via dyno runs is not infantry simple. It's hard for me to buy that Porsche left 11hp on the table that could have been recovered with a few spring clicks.

At a minimum, a careful analysis would have to be done re. what was changing (F/A, spark advance, etc.) in good runs vs. bad runs, and it would have to be repeated multiple times to confirm causality. Once can't just twiddle something, do another run and exclaim "wow, 11hp. Time to go home".

I'm pretty sure Porsche left fairly little on the table in it's intended configuration, but add 25 years, cat delete, mix-and match engine builds,and altitude variations etc., and it's not hard to imagine that the end result can be significantly out of tune, and we see it in bad A/F readings. When we correct the A/F's at WOT, we gain the power that was lost by being out of tune. In the end, we make very little more than factory power. It's not gaining power, just recouping what was lost. I'd agree 11 HP is not typical, but signficant gains are pretty routine. 128HP baseline is pretty low, so it's pretty safe to say that motor was out of tune. 139 HP is a healthy Spec motor. We often see cars running very lean (likely d/t the cat delete), and fixing that only seems prudent. At least anecdotally, the changes made seem to be pretty durable from one event to the next by Traqmate logged A/F ratios.

We can't advance spark, or almost any other parameter beyond replacing worn components, so we are only twirling one dial here.