To have a larger powerband. If its going to blow up at x rpms, I'm not going to rev that high, I'm trying to find out how high it is safe to rev to. If I stop making power at 9k (which I didn't), then I would stop there.

The engine was revved to 9.4k w stock ap1 head, so I was thinking that w upgraded everything in the head, I should be able to get another 1k revs without exploding?

This isn't a track car or anything, so safety/longevity is one of my top concerns, but if I can rev higher safely, why not?

I don't think I've been above 9.2 more than 5 times in the 15,000+ miles that I've been turbod and tuned, so its not like I will be bouncing off the rev limiter daily.

 

I don't understand why people care about power dropping off. If you are making a number for example, we will use 500whp.

Let's say you make peak power at redline for this example of 8k. Say you rev it out to 9k and it starts to decrease to 475. 10k rpm and it's down to 450.

So what?

When you shift you fall back to 350whp, and build boost, and go back up to peak whp.

Making 450whp for another 1000 rpm instead of 500whp is going to be faster than shifting anytime.

 

I would just love to see all the old peoples faces as they think its going to go bang, sniff miss the old sound NA made.

 

I was under the impression that making more power at a higher rpm has less stress on the engine as opposed to making the same power at a lower rpm. That is, as long as the rotating assembly is properly balanced and can rev that high.

Ex.
If you make 500 peak whp at 10k rpms, you'll be making less torque than a similar setup with 500 peak whp at 9k rpms. Less torque thus less cylinder pressure and less stress.

 

I don't think torque is the right word in your example as torque can be derived from HP using a mathematical formula, and examining the formula shows that if HP is constant then tq will decrease as revs increase, so your example is just another way of saying that observation.

Curious about engine stress though. Interested to hear what others say.

 

Did you see where I said cylinder pressure? Torque is related to cylinder pressure. Reducing torque by shifting your powerband up in the rpm range results in less cylinder pressure.

 

do you adjust valves to same specs (lash, etc.) as stock on a built head (and being fi)?

 

Yes.

 

Cool, just wanted to be sure, thank you

 

Of course it's "harder" on the motor revving it out. IF your worried about stress, keep it stock, lol. Otherwise, rev that bish out son!