compression and cam = REVS

[NTPRacing#19]

ok in the 416 vs. 440 post everyone is talking about which one revs faster, well someone said that the cam duration and piston compression effects how quick a motor will Rev...

so if i were to have a high compression piston with an aggresive cam that keeps the valves open longer then that would make the motor rev slower then it could, right? I want to purchase a LRD cam and get mine built up to a 416 so if i were to purchase them what would i want to order for a CAM and what compression piston would i want for the motor to rev quickly.

OR would i have to get a very high compression piston to compensate for the longer valve duration.

thanks
Eldon

[Steve-o 400EX]

You need the longer duration to compensate for the piston, this will make the motor rev quicker because it can push the gasses outmore efficiently. With these motors everything is a never ending balancing act. If ya do one thing, there's 10 more things that must be done do make it run right and to get the most out of it. But if ya buy one thing, it gives ya an excuse to buy more.:devil

[Steven]

the key to quick reving engines is cylinder pressure.

as you increase your cam's duration, this reduces cylinder pressure.

counteract this effect by bumping the compression. thats why big cams need high compression pistons

[Steve-o 400EX]

Originally posted by Steven
the key to quick reving engines is cylinder pressure.

as you increase your cam's duration, this reduces cylinder pressure.

counteract this effect by bumping the compression. thats why big cams need high compression pistons

Yea thats what i was tryin to get at but it may have come out a little awkward.:ermm:

[NTPRacing#19]

ok thank god i read some posts and found some very important info on this . because i was just goin to get a cam and drop it in and i didnt even think about compression, it all makes very good sense and sometimes my common sense doesnt kick in.

[Steve-o 400EX]

Originally posted by NTPRacing#19
ok thank god i read some posts and found some very important info on this . because i was just goin to get a cam and drop it in and i didnt even think about compression, it all makes very good sense and sometimes my common sense doesnt kick in.

LOL, yea we all have our moments. When someone puts it in perspective it makes it easy to see.

[zoom400ex]

a 416 is gonna rev alot faster than a 440 but will have less top end......like they said before you have to add in the high compression piston to make up for the loss of compression by the cam

[Steven]

here we go again...

[punker69q]

Originally posted by zoom400ex
a 416 is gonna rev alot faster than a 440 but will have less top end......like they said before you have to add in the high compression piston to make up for the loss of compression by the cam

I never tried a 416 or a 440, but Mickey Dunlap wrote somewhere on this site that a 440 that will rev slower than a 416 is simply not well built.


I dont know what you guys want to say when you say that an engine "rev faster"
If an engine rev faster than another (under load), this mean that the engine simply got more torque to pull the load (more torque = more force = more acceleration....) simply think that f=ma
or force = mass*acceleration..... thats the newton second law...

Originally posted by zoom400ex
a 416 is gonna rev alot faster than a 440 but will have less top end......like they said before you have to add in the high compression piston to make up for the loss of compression by the cam

:huh a 416 will rev faster than a 440, but 416 will have more topend too, a 440 adds more tourque slows down the top end, it has a bigger mass to go up and down

[NTPRacing#19]

aight this was an okay thread, dont argue aboutt he 440vs416, its all friggen preferance. just ride your quads and have fun!

Originally posted by NTPRacing#19
aight this was an okay thread, dont argue aboutt he 440vs416, its all friggen preferance. just ride your quads and have fun!

whos arguin