Gregg Lee

Same assumptions as before
11.75 inch effective rolling radius to convert revs to speed.
2.0 3000-9000 rpm.
2.2 3000-8000 rpm
Torque taken from charts posted on TOV.

Gernby

Thanks! The 4.77 equipped 2.0 looks very comparable to the 4.10 equipped 2.2

solo2racer

Ok,

So after looking at the graphs that Gregg put together, I'm again wondering how the new car will perform on an autocross course. I don't think these graphs have indicated anything that I didn't already know.

A typical national level autox course consists of speeds between 25 and ~65 (top of second gear).

[ Gregg - maybe you can create an excel chart from 25-65 MPH with the old model going to first and the new one going to third in the parts they can/have to? Or email me the Excel file and I can do it. ]

Assuming that the old car will pound it down to 1st whenever the speeds fall below 45 for any length of time (tight turns), it will depend on whether the new car gains much by downshifting or not. It may be in gear too short of a time to benefit since it looks like 1st only goes to about 35. The old car has more torque in 1st gear than the new one has in second.

At the high end (above 57 according to Annie), the new car will have to go to third. The old car has more torque in second than the new one has in third.

It's in the middle that the new car will have a huge advantage. Between 40-55, the new car will have a significant advantage in that it will pull out of mid-speed corners better and should accelerate better down short straight-aways.

So it will become course dependent. If I had to make a guess, there will be many courses where one model will dominate the other to the point that the alternate model will not have a chance at all. And I don't think there will be many (if any) courses where both cars will perform equally.

This season will show what the breakdown is between the models at courses, but there will be indications just looking at a course -

- very fast sections connected with slow corners will favor the old model where it can go to first
- lots of mid speed stuff will favor the new model

There will also be advantages/disadvantages based on the suspension tuning that Honda changed between the models. There's not enough info yet to determine which baseline is better. The new model could be substantially better based on the new tuning or it could have significant problems that are only exposed once R-compound tires are used.

One area that I wonder about is the softer rear springs. Will this do a better or worse job of keeping the rear inside tire on the ground? If worse, will adding a large front bar to the already slower steering affect turn-in?

Brad

kitwetzler

hm, since torque is a force and horsepower is acceleration, don't you think it's much more appropriate to do horsepower to speed comparisons?

ok, this is probably not a can of worms that we should get into.

solo2racer

[QUOTE]Originally posted by kitwetzler
hm, since torque is a force and horsepower is acceleration, don't you think it's much more appropriate to do horsepower to speed comparisons?

Windscreen

[QUOTE]Originally posted by kitwetzler
hm, since torque is a force and horsepower is acceleration, don't you think it's much more appropriate to do horsepower to speed comparisons?

solo2racer

For me, the easiest way to remember how torque and hp relate is that

- torque is the amount of fuel burned in a single firing of a cylinder (how powerful the combustion is)

- HP is the amount of fuel burned in a given amount of time (the more gas you burn in a given amount of time, the more power you make)

Both of these quantities are intuitive when you think of it this way.

So to make big horsepower you can either burn a lot of fuel in a small number of combustion events (large displacement or forced induction) or you can burn a small amount of fuel in a large number of combustion events (high RPMs).

Brad

Windscreen

[QUOTE]Originally posted by solo2racer
One area that I wonder about is the softer rear springs.

payneinthe

If I remember my reading correctly, to reduce wheel lift on one end of the car, you want to increase roll on that end and/or decrease it on the other end. Hence the stiffer front sway improving the rear wheel lift problem. Seems that softer rear springs would also tend to increase roll in the rear, lessening wheel lift.

Gregg Lee

[QUOTE]Originally posted by solo2racer
A typical national level autox course consists of speeds between 25 and ~65 (top of second gear).

[ Gregg - maybe you can create an excel chart from 25-65 MPH with the old model going to first and the new one going to third in the parts they can/have to?