Join Date: Jun 2007
Location: North Vancouver BC
Question on Fuel and Knock
My understanding of the mechanism of engine control on these cars is that they 'hunt forward' until they hear a preset amount of knock - or rather 'pre knock', I suppose, and then back off slightly on advance.
The presets will determine how far into the knock region they allow things to get before backing off, and I'll assume (unless someone knows differently) that this is probably comparable on all tunes.
As I plan to attend the NASSAM event in Colorado next Summer, a question occurs to me. I have a Trifecta tuned engine with a large wheel turbo. It is tuned for our BC 94 octane gas. I am not going to be able to get that fuel in WA, ID, UT or CO - the best is probably 92 and I'll have to be careful to seek out premium without alcohol.
Question - under those circumstances I don't intend to use full throttle much if at all, but will the greater degree of knock I'll experience with the lower grade fuel cause any issues for the engine? Detonation is what collapses pistons/breaks ring lands, but will bouncing off the 'lower ceiling' with lower grade gas pose a risk, and if so what can a driver do to minimize that?
Maybe I' needlessly worried about this but I have always been sensitive to the issue - I run a knock sensor and advance adjustment on my vintage race car and I once blew a piston because I ran a solo event with a local club 'just for the heck of it' with the race car and blew a piston due to gas that was a few months too old - you can't hear knock in an open exhaust race car and you don't have time to watch gauges in a solo event.
Any of you tuner types got a read on this?
1957 Jamaican bodied MGA
1958 MGA Twin Cam (race car)
1962 MGA Deluxe Coupe
1971 Jensen Interceptor
2009 Pontiac Solstice GXP Coupe
2007 BMW Z4M coupe
Recently departed: 1965 Jensen CV8, 1969 Lamborghini Islero S, 1988 Pontiac Fiero GT, 1969 MGC roadster
Mods at https://www.solsticeforum.com/forum/f...thread-102178/
Bill in BC