sweanders

I don't understand why people don't do a search before diving into a discussion. It's all right here in the old threads.

Rick Carter

This will save you so much time Mark.The next time this discussion comes up just post this link; you won't even need to make additional comments.

mark kibort

Its almost everything ive been advocating!

excep, the part about HP-seconds, which is more accurate than area under the HP curve, or average HP, etc. (which ive talked about before as well)

In the last big battle, Glen and a few others were debating with me about the part where Power dictates torque at the rear wheels at any vehicle speed. what i left out , was the tires had to be the same diameter! (or the resultant thrust force would always be equal, regardless of tire sizes) He never responded back.


Mk

mark kibort

Amen to that!

mk

ShawnSmith

> Are you saying that I look silly on approach to my residence running 6000 RPM??? I thought all my neighbors really liked my car (explaining all the stares and finger pointing).

I picked an example of the S2000 since it's fairly well known as a peaky motor. Not much torque down low, but wind it up in the 6k to 8k region where it gets onto that second cam and it really screams. This works great at the track, but I kinda like the 928 for the street because a much larger chunk of max torque is available in the middle and low portion of the rev range. It makes the car more fun to romp around in.

I think the quote is that HP is king, but torque is your friend.

Richard S

Mark always said everyone needs to get together with a whiteboard and hash this out. I think Mark has found his whiteboard. Good article.

Rich

mark kibort

Ill tell you, it feels pretty good to see this argument finally turn around.

Its one of the first times that folks really got it in the end, rather than just the name calling, and then the classis, "im done with this thread".

There even one guy that quoted a top instructor to saying that its "hp for lap time, torque to win races". I equated that to something like:
" food for being heathy, but protein for being strong"

anyway, after all the disucussion, it really boils down to maximizing the power at any speed to maximize acceleration. And, this goes for comparing two same type cars with different type engines (Like the S2000 vs a Mustang, or the Audi R10 diesel vs the old R8 in ALMS racing)

This was a tough discussion, and they brought up some great questions and objections. check out how it ended!


Mk

sharkmeister85

I don't know about the "last big battle" (my apologies, since it seems there's been a few), but my recollection (fwiw) is that they usually start when someone suggests they want to change their final drive from the common 2.20 to the 2.72 (?) to make their car accelerate quicker/faster, whatever. You argue that this change makes no difference and is a waste of effort. At least that's my take on it (am I mistaken?).
Glenn

mark kibort

The last one started with a different theme, and i learned from my mistake on the very first one about saying that it "makes no difference". There are some differences and most of which are subtle, and apply to the speed ranges that would be used. Most were saying that its just better, unconditionally, and that was not true. it all boiled down to maximizing HP over any operational speed range. And, 1st gear is always helped, with one catch, as long as you can get traction. It started a long time ago when KC touted how much the 3.09 gear box helped the GTS, and how much more alive it felt on the track. I then came back with the actual ratios that showed the gear box was now basically an S4 gear box! (excpet for what i called, the "sub 1st gear which was never even used on the track, excecpt for coming out of the paddock )

I think the discussions were very good in the end and everyone brought up some great points and if forced me to dig deeper into the resourses to even better understand the basic concepts. F=ma just doesnt cut it, unless we are talking about the "F" at the rear tires! and that ended up being the point and catch all to most all of the discussions.

MK

John Veninger

He saved the best line in the article for last!

FlyingDog

I have a whiteboard anybody can borrow... you just have to erase the picture of an airplane on a conveyor belt.

worf928

Notice how the Ricer was able to close the acceleration gap with the short final drive?

Well, at least I didn't have to bring it up.

mark kibort

Wolf come back.........

it wasnt the short finial drive, it was the closesness of the gears.

Now, if the 6 speed was CLOSER still, then the gap would be narrowed even further. (they were comparing, 3speed, 4speed, 6 speed, etc, with the same gear spacing.

mk

mark kibort

Now that was funny! was that here that we talked about that???
Nahhh, it couldnt have been!

mk

JKelly

HAPPY THREE YEAR ANNIVERSARY!!! of this debate.
https://rennlist.com/forums/928-forum/178778-2-20-vs-2-54-ratio.html

Mark, thanks again for the 2004 race season CD.