Quote:
Originally Posted by PDUB
Brent ought to be able to nail this down pretty close with simulation software.
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You inspired me to finally track down where my Dyno2000 launch icon disappeared to.
I had a file on my 347 stroker, so I just changed the stroke on it.
T=Torque
stroke - T@2000rpm --- peak T --- Hp@2000 - Peak Hp
3" ----- 314 -------- 426T@5000 --- 120 --- 460@6500
3.4" --- 367 -------- 464T@4500 --- 140 --- 454@6000
4" ----- 446 -------- 510T@4000 --- 170 --- 448@5000
I put in the Hp and torque at 2000 rpm to show what Brent is saying about the torque curve is fattening up. Notice that at 2000 rpm the 3" stroke has 73.7% of its peak torque, while the 3.4 and 4.0 strokes have 79.1% and 87.5% respectively. So the lower rpm torque comes up, making a flatter torque curve.
In this case it is showing that the peak Hp is slightly less as the stroke increases. I believe this is because it is a single plane intake. As the rpm comes down do to the longer stroke, I suspect the single plane is hurting the power. Although the air flow should be the same, so maybe not. Brent may have a different opinion.
I did do one extra comparison. I compared the 3" and 4" stroke Hp curves. I then looked at the 3" strokes Hp at 4/3 the rpm of the 4" stroke to simulate changing the rear end gears. Specifically the 4" has 170 Hp @2000 rpm and the 3" stroke Hp is 170 Hp @ 2666 rpm. I had to use linear interpolation to get that number, as the chart is in 500 rpm increments, however I believe it is close enough. The point is that the Hp is the same if you shift the rpm by the same ratio of the stroke change. So if you use a 3:1 gear ratio on a 4" stroke and a 4:1 ratio on the 3" stroke the performance of the car should be about the same, theoretically. No doubt there are some other real world factors that I have not accounted for that will skew these numbers.
It is looking to me like the stroke just lets you run in a different rpm range.
Hybrid Mode
