Pumps Gas or High Octane

[FastKaz]

I got a 1500 cc DOHC has a blower producing 250hp with 11.4 psi STOCK. it has in 7.8 to 1 ratio but i want to put in 9.5 to 1 pistons without going to high octane..is this posible and is so what can i do?

 

[patprimmer]

Based on the void of relevant data, not likely

Run 100 octane or more and/or knock sensors and/or water injection and keep your fingers crossed.



Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers for professional engineers

 

[mattsooty]

FastKaz,

a CR change of 7.8 to 9.5 really is a major step and one which it sounds like you are ill prepared to make.

Why on earth are you prepared to make a radical change to your engine but are against using higher octane fuel?

There are many things that you can do to make running with that setup 'safer' and Pat has already started the ball rolling (though he must be in a good mood today to even bother repying to your post!).

My suggestion would be to go away and Google what effect the change in CR is going to have on your engine, learn a little about it - then come back with some more specific questions.

MS

 

[evelrod]

Well, I'm glad you "got" one...However, the changes you are anticipating to make will almost guarantee that you will likely not have one very much longer. :-(

Rod

 

[FastKaz]

thanks for the information.. my son is into racing with jet ski and i was just wondering