increase from stroking 2.2 to 2.4?

[skipdup]

I'm quite ignorant on engine stuff like this, so thought I'd throw it out here...
Currently running a 2.2 S-spec (with 40 webers) engine in my race car. 9.8:1 Mahle p&c. S cams. S heads. Nothing special.
It's somewhere between 165-170 at wheels on the dyno.

If I switched to 2.4 crank/rods, and left everything the same, what's a reasonable hp increase expectation?

Thanks,
Skip

[Henry Schmidt]

It's hard to predict horse power increase because the increase is not linear.
you are changing the dynamics of the engine in more than just size.
You will increase displacement, increase the compression and reduce rod to stroke ratio.
The size increase is minimal. Very little horse power in the change.
The compression will increase by .5 points. there is some horse power here if good fuel octane is available.
The rod to stroke ratio will effect the torque and the ability for the engine rev.
Best guess: 5-7 % with a reasonable increase in torque.

[skipdup]

Thank you Henry!
I suspected I was asking a question that wouldn't have a clear answer.
That said, I also suspected just bumping displacement wouldn't get me where I wanted to be by itself - which is a bummer.
I'm thinking (OK, WAGing) I need 10-15% increase. I'd hope that'd at least give me a fighting chance...