Quote:
Originally Posted by drewski86
You're right, horsepower is work(torque) over time, but that does not mean that horsepower is an irrelevant by product. Let's put NoDOHC's friends V8 RX7 vs an F1 car. The V8 makes 230hp and 360tq whereas the F1 car makes 800hp and only 200tq. Do you think the V8 will win because it makes 160 more foot pounds of torque? You would be wrong. Torque IS work, but horsepower DOES work. Here is a saying that puts it in perspective. "Horsepower is how fast you hit the wall. Torque is how far you take it with you."
You may want to check this site out.
http://www.vettenet.org/torquehp.html |
You're ignoring gearing in your comparison. Gear the F1 car with the same gearing that would be optimal for the high torque engine and it will be a slug. What makes any car go is torque at the wheel. The F1 car needs a very short gear to extract it's power potential and allow it to use it's 20k revs to
create torque at the wheel through gear reduction. Use the F1 correct gearing with the low hp/high torque V8 and, if traction is available, it will murder the F1 engine up to the point it runs out of revs which would happen very quickly.
Quote:
Originally Posted by drewski86
No it should coincide with peak horsepower, not torque. You said the G-tech showed peak acceleration at 7500 RPM and the dyno showed peak power at 7200 RPM. This is your own data that proves this as fact.
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Peak VE will
always coincide with peak torque at the crankshaft. Peak VE is the point at which the engine is operating at it's peak efficiency and will create the most torque at the crankshaft. Peak horsepower is a product of torque and rpm. VE will fall past peak torque but if it's maintained at a high enough level the engine will continue to gain horsepower due to the multiplier of rpm. This is why most engines will have a torque peak at a lower rpm than their horsepower peak. You will see this in fuel curves, as NODOHC has mentioned, with fuel injector pulse width required to maintain a common a/f ratio rising up to the point of peak VE and then beginning to fall past peak VE as airflow falls.
Quote:
Originally Posted by drewski86
That's because the V8 has a much broader powerband. I'm sure if you compare dyno sheets you will see this as true. Peak numbers don't win races, area under the curve does.
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Broader than what? A stock 6-port engine will maintain 90% of it's torque for around 4500 rpm. Most stock V8s on the road hardly rev that high let alone maintain torque across that kind of rev range. One of the nice properties of the NA rotary (even boosted for that matter) is that they have nice flat, broad torque curves.
Stock S5 NA
Boosted semi-PP
Stock 2008 Mustang GT v. w/CAI
