Hp vs RPM

[darnoced]

I notice that a lot of people go for engines that have lots of horse power. My question is... how much is "enough". Meaning how much do you actually need to get reasonable acceration to max. rpm of the engine. Wouldn't a smaller engine that revs higher actually give you a higher top end?
I'm just wondering as my little 2.5 seems to do pretty well everything that my son's 3.3 does (except flip over backwards when I hit the throttle), so that when my little 2.5 finally dies (I have no idea how old it is, how much fuel has been through it..etc) if just exchanging it orrr....upgrading to something larger is the way to go.
I haven't heard much about the RB engines on here...and I have heard that the .26 max has durability issues?

 

[frickenjoey]

the RB .23 and the .26 Picco max are both good engines. I have both. I know the .26 is just silly when dialed in correctly. The .23 I have not ran enough to real give you a good review yet. As the engine increases in RPM through the power band (area where most power is output) it get to an RPM range where its torque level is dropping very fast. ****Assumptions here**** The piston gets to moving so fast that it is actually moving almost as fast as the expanding gas in the combustion chamber and are no long extracting as much power from the burning fuel. So with the crazy high RPM less actual power is being produced from the engine. Which is why we all should swap to turbine engines....lol JK. That is my take on why engines start to loose power at their peak RPM. Someone else can chime in and prove me wrong......but until I get a better answer that is what I'm going with. (because I don't know any better!)

 

[darnoced]

I guess I was being a little vaugue. If I have engine A which will produce a reasonable amount of power all the way to say 43,000, and engine B which will only run to 35,000, wouldn't (in theory) engine A give me a higher top speed given all other factors being the same?
From what I have seen there is only so many combinations of gears for the T-maxx available and if you gear it for max speed(large bell, small spur) wouldn't a smaller engine that revs higher actually be a better choice than a larger, lower reving engine.
In years gone by I had two 'cudas. One with a 440 and other with a 340. The 440 would get me to 135mph really quickly but that would be about all that it would do. The 340 was slower getting to top speed but would peak out around 150mph. so the 340 was actually the "faster" and the 440 was the "quicker".
Is there an engine the small block realm that will fit into the T-maxx that produces power at a really high rpms(43 - 45,000)?
While the big blocks are doing wheelies, the small block can concentrate on going somewhere......

 

[olds97_lss]

The larger lower rev'ing engine typically has more torque throughout the RPM curve. A smaller engine with less torque takes far longer than a larger engine with more torque to get the truck up to speed.

Pretty much any engine with a load on it never reaches peak RPM anyway.

So, if you feel running the smaller engine suits your needs, stick with it. They run longer on fuel as a bonus.

For those that want power and speed, you can usually capitalize on a higher HP engine's lack of RPM's with taller gearing. But you still have enough torque off the line to be satisfied more than you would be with a lower HP engine.

Also keep in mind, HP numbers from manufactures are usually bench flow tests vs real world numbers.

Typical small blocks produce their highest torque higher up in the RPM range than big blocks, so you don't get as much punch off the line as if you had a big block that was geared tall enough to match top speed of a same vehicle with a small block.

For me, I like having an engine that is overpowered for the top speed I want to hit (which really isn't that fast in general). The extra power leaves me a larger tuning window so I can run a more powerful engine a bit richer but get the same "power output" as a lower power engine leaned as far as I can lean it. In the end, the more powerful engine lasts longer and more than likely runs less of a risk of overheating throughout a day.

 

[darnoced]

Thanks fo rthe info..makes sense to be able to keep the engine off a full out race tune for durability!