CLASS RACER FORUM - View Single Post

tgriffith · 04-28-2009, 06:58 AM

I asked a motor guy that question,,,,,,,he claimed impossible to answer,,,,,,,for the motor that has higher compression to have same HP,,,your going to have differences in other places that reduces HP,,such as cam,,,that alone may bring down rpm curve so that it wouldnt MPH faster

he tends to think that the higher compression,,,the easier to get it up in rpm...on the other hand,,,once the motor is turning higher rpm,,lower compression will have less resistence,,,

he tends to think that your answer is YES more compression would make higher mph,,,,,reason for this is that most motors like a reduction of timing at higher RPM,,,if Im not mistaken,,,once your retard your timing , doesnt that fire the cylinder closer to the top, thus having more compression???,,,,I think cylinder pressure would be higher at 28 degrees VS 36 degrees...or am I thinking about this backwards??

04-28-2009, 06:58 AM	#6
tgriffith Member Join Date: May 2002 Posts: 187 Likes: 0 Liked 0 Times in 0 Posts	Re: Compression Ratio vs MPH I asked a motor guy that question,,,,,,,he claimed impossible to answer,,,,,,,for the motor that has higher compression to have same HP,,,your going to have differences in other places that reduces HP,,such as cam,,,that alone may bring down rpm curve so that it wouldnt MPH faster he tends to think that the higher compression,,,the easier to get it up in rpm...on the other hand,,,once the motor is turning higher rpm,,lower compression will have less resistence,,, he tends to think that your answer is YES more compression would make higher mph,,,,,reason for this is that most motors like a reduction of timing at higher RPM,,,if Im not mistaken,,,once your retard your timing , doesnt that fire the cylinder closer to the top, thus having more compression???,,,,I think cylinder pressure would be higher at 28 degrees VS 36 degrees...or am I thinking about this backwards??