I've been searching through here and can't seem to get a definitive answer on this one... I saw a dyno readout by Fabspeed a few years ago when I had my 430 headers done, showing a before and after bhp & Torque for replacing the headers. I seem to remember seeing the torque had dropped significantly in the lower rev range after the headers were fitted, which was questioned by some F-Chatters and Fabspeed retracted that dyno stating it was the wrong one - it was low because the exhaust valves we're jacked open (vac hoses plugged). The second dyno they produced showed the exhaust system operating as normal with lovely gains across the board and so I got the headers and I do not regret it one bit - they are fantastic and the sound and throttle response is significant. My question however is this: I see a few F-Chatters have jacked their exhaust flaps open full time - are they losing torque? I'm using my Spider less and less now and I'm considering jacking them open myself as I have done on my RS5 audi with Capristo. I assume the lack of low down torque is redundant because who is looking for power under 3,000 rpm right? After 3,000 it's all operating exactly the same anyway so maybe it's worth sacrificing a bit of pull in 5th and 6th at cruising speed for the sound. Thoughts? Experience? Cheers lads
The mid range torque dip (from larger tube 4-1 headers) occurs around 5000rpm so having the valves open all the time wont affect it.
