Murray

In troubleshooting my HVAC system I found that the vacuum line to the flappy had a hole in it. It was losing all the vacuum and was affecting the HVAC operation. I replaced that line and now both the flappy and my HVAC work.

My question is in regards to the impact of the flappy valve. I believe it wasn't working since I got the car. However, the car ran well and seemed pretty quick. It dynoed at 262 whp and 272 lb/ft earlier this spring.
How much impact on performance should a functioning flappy have? Because based on my seat of the pants dyno...WOW...the difference is really noticeable. The acceleration around 4k rpm and the sound difference is way more than I would have expected from just the flappy now working.

Thanks.

928 at last

Murray,
The flappy does make a difference in the mid range. If you do a search there's lots of info on the forum.
Best,
Rob.

IcemanG17

the flappy doesn't effect top end performance much, but it makes a HUGE difference in the middle..you can really feel it in the "butt-o-meter"....here is a dyno sheet showing the difference....take the black AFR line out...the blue torque line is the difference in the midrange.....

Murray

Thanks for the replies. I will search some more, but mostly I will just enjoy the new found butt kicking mid-range acceleration.