octanes,the power limit of an engine is air not gasoline

[Longbone]

Originally Posted by raaaid

i heard a lot on how spit i and 109 are porked for using low octanes, well:

what limits the power of an engine is how much air you can put on the cylinder, thats why turbocompressors are cool

if theres one mol of 02 you can get a limited amount of mols of H2 and C burning

if theres no enough air in the cilinder it doesnt matter you rise the octanes or put more fuel it wont burn

in other words it has identical effect on terms of power inject more gasoline to inject less with higher octanes

edit:

methanol injection i guess its different, its a different reaction which with the same amount of O2 you get more heat

but more or less octanes dtermines the proportion of H2 in the fuel

you can put in the cilinder lot of h in litle fuel or litle h in much fuel, its the same

what has me clueless is water injenction, anymbody knows the advantage

whay cars not use water injenction to save fuel?

Hi mate
read this
http://autospeed.com/cms/title_Water...0/article.html

EDIT: How can this solve our problems ? Higher octane == higher FPS ???

[Hexcaliber]

A higher octane rating results in smoother engine running, it is a measure of how prone a fuel is to pre ignition, the higher the rating the better. In terms of performance, as already mentioned, a poor octane number results in pinking, or knocking, this throws off engine timing, results in poor compression, and causes excessive wear and damage to an engine even over relatively short periods.

The better the octane rating of a fuel, the better the compression ratio that can be used, an important factor when determining engine output and directly affecting relative engine performance.

Piston engine performance relies on more than a simple chemical interaction of hydrocarbons and air at the cylinder face. For the technology available during the early part of WW 2 the performance advantage of the higher octane fuel was significant. It allowed better compression ratios, meant lower maintenance over heads due to reduced wear and allowed engines to perform as close to optimal as was possible, for longer periods of time.

While water injection helps offset pre ignition, it also means the engine is far more susceptible to damage, and brings an entirely new set of problems to the table when considering fighter aircraft.