Hi,

Maybe this has been asked numerous times before. If that is true im sorry.

However, is it possible to increase the volume of the 13B by enlarging the bathtubs on the rotors?

And do you know if this has been done before?

I was thinking that even with a small enlargement (1mm wider and deeper overall) my thought was that the power would go up very quick too.

Im interested in your comments

Regards
Rogier

 

I'm certainly no expert on the topic, but the rotors are not particularly thick. The depth of the recess effects the compression ratio. For instance a S4 turbo rotor with 8.5:1 CR has a deeper recess than a Renesis rotor with a 10:1 CR. The displacement does not change from 1308cc when using one of those rotors compared to the other.

 

youre right about the volume. But with a turbomotor you want a lower compression, thats odd that the s4 has a lower compression than the S6....

 

Changing the size of the bathtub has zero effect on displacement and lowers compression ratio. In other words, the engine will make less power than it did before, all other things being equal.

-Max

 

I thought that it would increase, whats the background that It doesnt increase?

 

Displacement is swept volume; the difference between maximum and minimum volume. So milling more out of the rotors inceases total volume but swept volume stays the same... and swept volume is what determines how much air/fuel is being pumped in.

Here's an example... think of a very simple 1 cylinder engine. Say, 1 square inch of piston area, and 1 inch stroke. So it's moving 1 cubic inch every 2 revolutions. Well, now make it so the cylinder is 2 inches tall. The total volume is, at BDC, 2 cubic inches, but it's still only moving 1 cubic inch every 2 revolutions.

 

VERY simple make the chamber smaller , more compression means more power, quicker spool better response, less fuel, all the good things, but now control the DETONATION. nothing ever really changes on infernal combustion engines.