The video you posted is irrelevant -- they're both starting in 1st gear, and we've been saying all along that the geared car always has the advantage when the race starts in first:




These two statements contradict each other. The first is not true at all; the second is on the right track!

Think about it for a second....if the lower geared car is near his shifting point (it's more like 1000rpms, not 500), the higher geared car has already shifted. Here's a breakdown of a race between the two, starting at 60mph:

...............gear...........rpms
.............@60mph......@60mph
========================
3.538FD.....2nd.........~6500
4.083FD.....3rd.........~5240


The 3.538 car in this example has an overwhelming advantage -- he's in the meat of his powerband (6500 vs 5240), and is still in 2nd gear, which has a 30% torque multiplication advantage (1.624/2.324=30%).

As soon as the 3.538 car hits 7500 and has to shift, he'll be in the lead....but now both cars are in 3rd gear, and the 4.083 car will catch up & pass...until he shifts into 4th, at which point the 3.538 car will still be in 3rd and in the meat of his powerband again, and it will go back and forth like that.

The above is not just theorycraft or opinion. It has mathematically been proven, and there are videos (albeit, they are hard to find) showing it in the real world.




What you're looking for exist(ed) in the thread we posted (it's also a sticky in these forums). Unfortunately, the video has been removed -- I just checked. But you can easily tell from the following comments what the outcome was -- the cars accelerated almost identically, even though one had gears.

Everybody that is reading this should read the sticky on Gears that was posted above. It is a long thread, but there is valuable information there.

 

^^^

Valid post is Valid...


During some road testing I'm no expert, but shifting hurts!

I shift at 7500-7700ish rpms...car is crazy long and sexy!

 

Yes I did lol.. I was just being general. But wait, you're saying that the area in between the curves is equal for both gears? Really? Clearly the area between the gears in the first and second gears is way bigger than any small area difference in the higher gears that benefits the lower FD, or maybe I'm just crazy who knows.

BTW I made it through a few pages of that thread you guys keep referring to months ago. Too many trolls and noobs here makes reading threads like that painful. (Probably what this thread has become hahaha..)

Cheers.

 

You can't just look at the curve -- that completely eliminates the torque multiplier, which is the bigger factor. It's a 30% difference between 2nd and 3rd gear!!

Multiply gear * FD * whp (or wtq) at a given rpm. This will give you an accurate depiction at any point in time on which car is pulling harder.

Even if both cars are making identical HP, 2nd gear * 3.58 is a larger figure than 3rd gear * 4.083....

 

wrong

 

Read the entire thread to get the context. He's talking about overall acceleration in an all-out drag race starting at a speed above first gear, in which case this is correct.

Obviously, if a 4.083 and 3.583 car both start in the SAME gear, the 4.083 will accelerate harder. That has already been stated numerous times.

 

Don't you guys think just the fact that your going through the gears faster means that the car is accelerating faster. When you got your foot in that thing and your shiftin at redline....you drop it into that next gear and you are already in the powerband. With a geared car it is already pulling through the next gear while the un-geared car is still riding out the previous gear. I don't think torque and all these numbers play as much of a role as you think. Simple fact is that it is going to accelerate faster.
Motorcycles are a whole different book here but I had 2x 2004 GSXR-600, one stock and one geared with up 2 in the rear and down 1 (teeth) in the front. I can say that there was a significant difference in the two and that the geared one was faster. I believe that the Z is going to follow the same logic in that the geared one will be faster.
Also, if you really want to get technical. What if you split the difference in the gearing and compare the 3.5 gears to the 3.9 setup....
There isn't going to be as much of a difference but do you think those few miles per hour in each gear are really going to allow the 3.5 gears to keep up with the 3.9?
The 3.9 is going to accell faster and ultimately pull ahead of the 3.5.

 

No, and I have 3.9 FD.
it just doesn't work in that way.
you are EXACTLY in the same powerband shifting as you'll be with ANY FD... (because you changed that and not the gear ratios in the gearbox).

 

You're making it sound like it is bad to "ride out" 2nd gear. The final drive is just another gear ratio. You can't say:

"a shorter gear ratio is better when comparing final drive gears"

...and then turn around and say...

"but a taller gear ratio is better when comparing 2nd and 3rd gears"

The argument here is between a 4.083 car in 3rd, and a 3.538 car in 2nd. To get the effective gearing at the wheels, you MUST multiply the final drive ratio by the gear ratio.

So:

4.083 * 1.624 (3rd) = 6.63 overall gear ratio between the engine and the wheels

vs.

3.538 * 2.324 (2nd) = 8.22 overall gear ratio between the engine and the wheels.

Forget everything else -- it doesn't matter WHERE the gearing comes from, the overall gear ratio is all that matters. Obviously, this is only the case so long as the 3.538 car is in 2nd. When they're both in the same gear, the 4.083 car obviously has the gearing advantage.

Now the tricky part is throwing the "time" variable in, as well as the fact that each car is in a different part of its powerband. It's easier just to look at videos. And again, the scenario we're talking about depends heavily on the speed at which the race BOTH starts and ends. I keep coming back to this, but....don't you think a stock geared Z in 2nd gear would be faster from 60-70mph than a geared Z in 3rd from 60-70? Assuming the race STARTS at 60...(no momentum building from 0).

 

No, YOU'RE wrong. This is fun.

 

That first S2K video is worthless because the S2K you see fading has a much worse driver. You can clearly see him fall a lot on each shift.

That brings me to the other point, its very hard to get equal drivers for comparisons. Many guys who do gears are actually SLOWER. Not because the gears couldn't potentially help their times, but because they have more shifting to do.

My times NA, vs a friends here (Aceman) NA, both about the same hp. He can drive well. He had 4.08's and cut 1.8 60fts, I ran 13.1, he ran 13.0. I trapped 107mph, he also did. You could argue his gears didnt do $hit because he beat me down the 1/4 by a tenth because of his slightly quicker launch.

In some cars they are great. In HR's and 370's with these stupid long (for NA) IMO gears a good 3.7 or 3.9 set is where Id be if I was modding to stay NA.

Again though the problem is people with gears should have spent the money on driving so the real times (ie. advantages) are yet to be seen IMO. edit-that guy who runs 12.3 NA in his 370 can drive his a$$ off and had gears. Nobody else with mods/power like him is even close. That shows you that when exploited by having traction and shifting skills, they make you faster EVERYWHERE, not just in first gear, which is utterly stupid to say IMO.

 

They only make you faster if all else is equal...including the gear you are starting in.

You can't tell me that a 3.538 car starting in 2nd from a 60mph roll isn't going to get to 70mph faster than a 4.083 car starting in 3rd from a 60mph roll.

Overall drive ratio of the stock geared car is 8.22:1, starting in the meat of his powerband, vs 6.63:1 for the geared car, starting at the beginning of his powerband...

You can't look at the FD in isolation -- you MUST consider the gear ratio that you are in as well. In cars that are geared differently, it's inevitable that they will be in different gears at some points.

 

Please explain how they make you faster "everywhere". Nothing in your post supported this.

 

^^^^^ this thread is so off topic!...... This argument belongs in the drivetrain section of the forum.....

 

^^ you started it Lakeside. This thread is evil.

 

N...A... All The Way! :chant: