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[JoeVibe]

For my performance expert friends,

I was asked a question that I didn't have an answer for and I can't let it go.

Specifically, if you have the heads ported with bigger valves and have the intake ported, but leave cam and exhaust alone, I assume you'll get bigger TQ and HP numbers but what will it do to the curve?

After re-reading this, I thought a little more info would help. The bike already has aftermarket cam and exhaust.

Joe

[GregKhougaz]

Are you expecting a simple, concise answer?    Try reading this article:  Torque Curve Adjustment

[JoeVibe]

Are you expecting a simple, concise answer?    Try reading this article:  Torque Curve Adjustment

Not at all. Right now the bike starts making power at about 2300 rpm. We were discussing  if making intake changes would move that more to the higher rpm range. I'll check out the article you attached. Thanks!

[TN]

Joe, my limited experience with your question is I replaced a set of heads on my first go around with the 117” kit to my FLTRSE3. I bought a new set of heads and shipped them to John Sachs, told him what my build was and requested a 100k mile setup, I wasn’t concerned with dyno numbers at all. The one thing I noticed he did was increase the intake valves size ever so slightly and cc’d my heads to match the requested static compression for my cam. Everything else stayed the same.

I later had my bike put on same dyno to verify the ve values and they were very close, a slight change was made in a specific area was all the tuner did. I ended up with a  8+ hp gain, a slight increase in torque and most importantly from my observations a broader curve on dyno sheet. No real change in where power came on but it didn’t fall off as quick.

This is from my real world experience.

[JoeVibe]

Thanks TN. That's what I would expect but I've never claimed to know what the heck I was talking about. I appreciate your feedback!