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Author: Subject: increase BHP = increase in viberation
bikecarbfred

posted on 1/5/22 at 08:08 PM Reply With Quote
increase BHP = increase in viberation

As the title suggest ; I had advanced my timing at top end. There was deffo no knock. but I had noticed that on the KS3 knock detection the frequency/knock range had increased slightly so before when I was getting around avg 40 knock count when racing hard it is now around avg 48 therefore I am assuming there is a correlation between more BHP = more vibration.

This is probably why the "gain" setting is used to be able to configure the BASE setting of 40 on all engines at max WOT so that 100% knock is detected around 80.

Therefore I will decrease my gain to around 10 or whatever is needed to get it back to around 40 on full WOT/RPM.

But it's something I Have learnt new yesterday

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snapper

posted on 1/5/22 at 09:51 PM Reply With Quote
There are a lot of assumptions in your statement based on a digital knock sensor and the assumption you have more bhp by advancing ignition… or you have more info that you haven’t shared.
Advancing ignition arbitrarily is dangerous, knock is an engine killer.
A knock sensor indicates detonation before you can hear it.
Higher octane fuel and/or octane booster helps eliminate knock.
What octane fuel are you using? Is there a higher octane available?
Don’t ever modify a sensor to get the result you want to see, you want to see no knock.
Forged pistons are more tolerant of knock but essentially no knock is better.





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bikecarbfred

posted on 1/5/22 at 09:55 PM Reply With Quote
I made more bhp because it was the car flying like mad lol

yes im using 99 ron V-POWER

edit:im also using h-beam rods

[Edited on 1/5/22 by bikecarbfred]

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Mr Whippy

posted on 2/5/22 at 06:38 AM Reply With Quote
Reminds me of friends "tuning" their bike timing when I was a teen (a long time ago) only for them to sport holes in their pistons shortly after
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bikecarbfred

posted on 2/5/22 at 07:03 AM Reply With Quote
hahahhahaha true; There was a method to my madness and I have my eyes glued to the knock sensor and i wILL not be increasing any further.

Timing table below. increases vaues on right hand side.



The SLIGHTLY higher frequency was recorded around 4000rpm in 2nd gear. All rest was fine.

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johnemms

posted on 3/5/22 at 07:47 AM Reply With Quote
If you're interested...
I bought a gunson electric stethoscope cheap tat..
Took the mic out the end wired in a jackplug..
Stick it in the KS3 - in ear headphones.. ear defenders over the top..
Interesting listening to the sounds as you mod timing..
PS. took my blacktop RR and added 31+ timing - no increase hp..
Dropped it to 28-29 and it made 2 extra hp





Own chassis & Build - First time pass!!
"7's" aren't really "cars", they are 'experiences"

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SJ

posted on 3/5/22 at 01:29 PM Reply With Quote
quote:
Originally posted by Mr Whippy
Reminds me of friends "tuning" their bike timing when I was a teen (a long time ago) only for them to sport holes in their pistons shortly after


Seemed to happen about every other week with my 1976 Suzuki AP50!

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coyoteboy

posted on 4/5/22 at 09:29 AM Reply With Quote
This is why you need to be on a rolling road with det cans. Unless you know (have designed and extensively tested yourself) the knock sensor system, all you can do is assume that there's increased knock (even if you can't hear it) and you're knock limited.

I ignored minor knock that occasionally occured (knock sensor didnt trigger). I now have a piston without a ringland.

[Edited on 4/5/22 by coyoteboy]






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bikecarbfred

posted on 4/5/22 at 05:28 PM Reply With Quote
Can you remember what rpm and gear you was getting that slight knock in
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