dmudd wrote:now that thats settled why do some cars like the 3000gt and catalic require premium...
sxysweed wrote:They're good for cool points on NWP and that's about it.
jdmtruong wrote:had some rotas but u know gotta have the real rims
ollie wrote:Spyke=correct.....running premium in a stock crx engine is a waste of money..
Higher octane fuel is used to help prevent detonation.
dmudd wrote:whats the stock compression for our motors including the b16? i know the 3000gt na is 10.1 and it said premium only.
JohnnyBlaze wrote:dmudd wrote:whats the stock compression for our motors including the b16? i know the 3000gt na is 10.1 and it said premium only.
As mentioned above, the 3000GT is a turbo engine and requires premium to prevent detonation.
Dave_Darling wrote:Lots and lots of things change the propensity of a given engine to ping. The octane of the fuel matters, of course, as does the ignition timing. The pressure of the ambient air the engine is pulling from (high altitude or low), the amount of boost if any, intake air temperature, how wild or mild the cam is, the combustion chamber shape, the presence or absence of hot spots or sharp edges in the chamber, the number and location of spark plugs, the mixture quality, how rich or lean the mixture is, and on and on and on and on. All of those things affect if an engine pings or not.
Most engines today are built with knock-sensors that can tell when pinging starts. They can then pull timing out (and boost if they have computer-controlled boost) or richen the mixture slightly until the pinging goes away. So they can run higher compression and count on the engine management system to make sure the engine doesn't destroy itself.
Our engines are a little older, and do not have a knock sensor. (Not on a stock US-spec CRX, at least.) So they had to be a little more conservative with the compression and timing and such, to leave some margin of error.
Some even older engines (VW Bug ones, for example) are even more primitive. Because of the sub-optimal combustion chamber design, the very primitive engine management system (centrifugal-only spark advance in some cases, and a single carburetor in most cases) and other factors, they have to run premium fuel when they get over about 8.0:1 compression.
Nice write up thanks explained alot
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