piston diameter please
17 November 2009, 03:59 PM
#6
Scooby Regular
Join Date: Jan 2006
Posts: 3,695
Likes: 0
Received 0 Likes
on
0 Posts
While not for a second wanting to get into a "my number's betterer than theirs", Phormula themselves say that their calculator produces an estimate - and it must be pretty rough as it only uses bore as an input.
Comp ratio, piston/head design, piston velocity (i.e. rpm), charge temp, the moment in the compression stroke that the det occurs will all (along with other things beside) influence the frequencies produced by the ping, and electronic knock monitors - Phormula's presumably included, will/should pick up noise from a range either side of a selected centre, so the exact setting of the frequency shouldn't be critical (and I would hope not given that their boxes "only" seem to go down to 6).
For what it's worth, that 5.5kHz figure I mentioned came off a spectrum analysis of an EJ20, not a generic calculator on the web. If I was using one of these boxes I'd set it at 6. Make of this what you will!
Comp ratio, piston/head design, piston velocity (i.e. rpm), charge temp, the moment in the compression stroke that the det occurs will all (along with other things beside) influence the frequencies produced by the ping, and electronic knock monitors - Phormula's presumably included, will/should pick up noise from a range either side of a selected centre, so the exact setting of the frequency shouldn't be critical (and I would hope not given that their boxes "only" seem to go down to 6).
For what it's worth, that 5.5kHz figure I mentioned came off a spectrum analysis of an EJ20, not a generic calculator on the web. If I was using one of these boxes I'd set it at 6. Make of this what you will!
Thread
Thread Starter
Forum
Replies
Last Post
Matt_182
Wheels, Tyres & Brakes
19
07 October 2015 01:05 PM
bluebullet29
General Technical
9
05 October 2015 02:17 PM
