Two big take-aways…
Rigorous testing is really hard.
The MAF can make uncompetitive engines, competitive. Surprisingly.
We had problems testing. Mostly what we learned is that cars are not that healthy. A car that is really squared away has a newish (therefore pliable) hose to the idle air control valve (IACV) and the pipes going into the throttle body are epoxied in. But what we found is that most cars (4 of 5) had none of that. So every time we touched the intake tract, there was risk that we were either introducing or fixing a vac leak. Controlling for that variable is hard with intake tracts that are not in good shape.
Of those 5 cars, we got 3 on the dyno. These #'s are coming from recall. I’ll check the data tomorrow.
My car went from 154hp/149ftlbs to 160/155. But I’ve got some other issue going on that is making my dyno curves jagged. It’s impossible to accurately compare 2x jagged curves. The peak of the jagged was 154hp and 160hp but if one ignores the jags, it’s prob 2 less. I note that my 6hp is in line with what the Aussies told us to expect.
Fred Switzer’s car went from 145hp to 155hp. Then we took the MAF off to confirm his AFM #'s and instead of getting 145 again we got 135. We decided that messing with his intake had caused a vac leak.
Philip Springer’s car was being driven by Scott McKay. It got 150hp with the MAF. Scott said that the engine was “completely not competitive” w/o the MAF. We were just too damned busy to get Philip’s car on the dyno again with his AFM. Scott loved the MAF so much he was raving and gesticulating wildly.
So what does this mean? Well, other than my points above, I don’t know. But it’s pretty damned interesting that the MAF turned both Fred and Philip’s cars from “uncompetitive” to “competitive”. It’s easy to imagine the guy that perceives that his engine sucks so he’s contemplating dropping $6k or more on an engine rebuild and then all the sudden that MAF makes his engine competitive. That’s a dimension of this that had not been considered.
Scenario 1. The engines got went from uncompetitive to good hp because the AFM was the problem? That’s cool.
Scenario 2. The engines got good but it’s actually old and worn out. So if everyone had a MAF the engine would just be uncompetitive again? That’s not useful.
Charlie Diradour is taking the MAF to Mid Atl now.
The only way we’re going to get good #'s with this thing is for it to get some dyno time on some healthy engines with nice smooth dyno curves. In order to seriously consider whether the obvious disadvantage of “change” is far outweighed by the charms of no more AFM problems and chipping DMEs going away, we need dyno #'s in order to have an idea as to what this will do to the dyno rule. And SE did not supply that. Sorry.
Hopefully MidAtl can do better dyno testing than we did.
Thanks to Dave Walsh’s Group3 Dyno for all their work.