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I agree with Kevin H. that there is almost no time lost on an upshift. And, any acceleration will make you faster than sitting on the limiter. I also agree that the downshift can be invisible, especially under hard straight braking. But there are times the downshift can cost you time if you upset the car's balance in a turn or lose focus in a technical section.

One thing you might try in a car with good power (like the WRX), is to not worry about dropping back to 2nd so quickly. If you are on fairly fast section and the engine is still in the power band, just keep it in 3rd for a while. It will do 2 things for you. One, the car will be a bit less twitchy, and two, it'll force you to smooth your driving out to conserve momentum. When you're in the right spot where the downshift can be achieved without problem, drop the gear then.

I've used this technique many times and it usually feels wrong because the car isn't as responsive to throttle - however the clock usually shows it to be the right thing. YMMV, but give it a shot on your 3rd run sometime - you might be pleasantly surprised.

Good power and WRX in the same sentence? I think not! The WRX is still an inertia car. It's nowhere near as bad as the Jetta was but then few cars are that slow... About the only point and shoot cars are things like Corvettes, Jim's turbo Miata, and 911 turbos.

I do quite often "lug" the car in 2nd as it's just too upsetting to the balance to get back into 1st. 2nd goes to about 65 in the WRX so I rarely use 3rd. (3rd goes to 97!)

We're way off the original topic here. Maybe the gearing/shifting thread could be split off from the original thread.

--Kevin H.

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2003 WRX (again!)

Well, I timed the car on the way home from work this afternoon, and it went from 48-62mph in 3 seconds (in 3rd gear). Took about 1.5 for 48-55, so apparently my estimated 55mph avg speed was correct.

Also wanted to add that I've been using that same technique of measuring whether there was a power gain for several years, Dick. I use a 2000-5000 rpm run in 3rd gear and a 2000 rpm to redline/ rev limiter in 2nd. I've cut about a second off each time from when the car was totally stock. And the flywheel actually contributed about 0.3-4 sec of that!

About the downshifts - one of the reasons I went back to the stock diameter last year was because I was having such a big problem deciding WHEN I should downshift once I had shifted to 3rd. Some spots, I would downshift only to be right back on the rev limiter again; but if I tried staying in 3rd I ended up almost spinning because I was so used to controlling the car with the throttle. At the test&tune on Sunday we had a 3rd gear sweeper into a medium-fast slalom, which I mostly downshifted for (and upshifted again when exiting), but ran through a few times in 3rd. Felt really weird, but the times were about the same either way.

Definitely looking forward to trying some different things this year.

0-60 in 5.5 sec and AWD is an inertia car? I guess it's all relative, but that's pretty near the quick end of the performance spectrum in our club!

I tend to think all cars are "inertia cars"-- at least if you want to go fast. While faster cars can be driven in a point and shoot style and still turn a respectable time, if you treat them as a momentum car, they should nearly always be faster. That was certainly the case with my (former) Miata.

My first run through a course usually resulted in a "point and shoot" run mainly due to the fact that I had to get used to the available rear traction for the day. After changing to a more conservation of momentum style for subsequent runs, I could always drop seconds off my original time. In a few cases where the surface was slippery/greasy (like Little Joel in Winston Salem), I was usually much faster turning the boost/power down.

Jim

I know I am contributing to the off topic nature of my own thread but....

I don't have my laptop at work with me today and it has my GEEZ software and data from some runs from last year, but if I remember correctly I didn't think upshifts took that long or seemed to hurt that much when looking at the data. But I only have data for a 1st -> 2nd shift.

I am sure you could use something like GEEZ and setup some simple tests to see how long you can sit on the rev limiter before it would have been better to upshift.

Back on topic....

So, it sounds like Aaron and others are not as concerned about trying for a magical 60 mph in second. Especially if your car already is geared in such a way that stock diameter wheels/tires does not get you close to 60 in 2nd?

I guess then the next question would be. If your car DOES put you at about 60 in 2nd with stock wheels/tires. Should you abandon that goal and specifically seek out smaller diameter tires that alter your gearing significantly? Especially if you have a peaky engine with not as much torque down low?

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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.com
Money can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.

Try driving one out of a corner. Without the benefit of an AWD launch the WRX is a bit of a dog off boost. My Celica GTS will easily run with (or outrun) a stock WRX in a 5-60 mph race, add in a launch and it's all over after the first 5 feet (not in my favor).

Scott

The reason I don't care about the magical 60mph # is that all of my power is up top, thus making gearing extremely important. For cars with low end torque, this may not matter, but mine is non-existent.

As for shifts not costing you much, the .5 second rule was told to me by a host of good drivers, including Tim Aro, Jonathan Roberts, and Sam Strano. Whether or not it's factual depends I think on the course and the point of upshift. Most of the same drivers state that if you're going to hit the limiter more than 7 times in a row, you should shift as well, but sometimes the limiter keeps the car stable as well...

With the weather in Atlanta being very sketchy for this weekend, my guess is that hitting the limiter may not be an option anyway... - AB

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'14 Toyota Sequoia Platinum 4WD
Super Westerfield Bros - '93 Integra - LeChump Du Jour
STX 93 - Scion FR-S

According to the Miata Tire Calculator, going from the stock 215/50 16 to a 205/50 15 kills my top end, 58.change to just under 55. But, it'll get there quicker. As one of my distinguished 1WD coworkers told me, shortshift into second after launch (when applicable) and forget about it because of the low-end torque that I have. Which is choice.

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Has no responsibility whatsoever.

In general, I believe that the priority should be for the tire size that gives the best grip without having a significant negative effect on acceleration or significantly increasing the number of shifts and/or rev limiter time on typical courses. In autocrossing grip is more important than acceleration potential. This includes both cornering grip and acceleration grip. Remember, if you can go through the corner quicker and get on the gas sooner due to more grip you may already be at a better point in your power curve. The biggested problem with short gears (if you have a choice) is having to shift to the higher, slower accelerating gear. Due to the shift time, a taller second gear with no need to shift MAY give a shorter elapsed time more often than using a shorter second gear, coasting for half a second during the shift, and then accelerating at a lower rate in third gear. Only "testing" and "math" can give you the answer.

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Dick Rasmussen

FS 50 2018 Mustang GT

One way to look at the tradeoffs is as follows: IF you normally have wheelspin exiting typical corners you need more grip not shorter tires/gears. If you have wheelspin until the tire(s) hookup and then the engine bogs, you have a real challenge.

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Dick Rasmussen

FS 50 2018 Mustang GT

Or a Torsen.

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Has no responsibility whatsoever.

i'm going to a 16x7 wheel (215/45 azenis) from 15x6 (205/45 azenis) heavy ass stockies.

my main reason was that i wanted the increased width in tire. also, now that i'm in the turbo with an open diff, i imagine that i'll get some decent wheelspin and i didn't want to increase that with smaller OD wheels.

the test and tune will be my first chance to run with the 16's so i'll know more after that.

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05 MCS

try being me right now.. an automatic trash can for gearing (hopefully 5sp before seasons out, no power 4A-c what else can be said that with the tiny 13's I can't even spin a tire in the rain. but hey at least I got the corolla real cheap at $240 after a recent rebuild.. so the tire concept isn't even an issue with me yet caus you have to be losiing traction to have to try and find some grip.... right??

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beware of EV powered Ford EXP's they are quiet and come for you when you least expect it... hide behind an aluminum light pole...... ya that will help