Shifting my '11 WRX - Need some advice from experienced drivers

[catinthehat]

Hello all,

First time poster on these forums and have not made my official introduction yet (but I will!). I am a weekend track days car enthusiast, and make it out to maybe 6-8 trackday weekends a year, as well as the frequent Sunday morning group drives through the canyons. My track car is a customized Lotus Exige.

I recently picked up a '11 WRX sedan and just love it! I am having trouble with smooth upshifts though and wondering if those with more experience than I could shed some light. In my Lotus, smooth upshifts was a breeze. I'm not sure if it was because it was a 6-speed with closer gear ratios or lighter flywheel or what. But I could basically redline upshift in every gear lightning quick and get super smooth upshifts. Just simple accelerate, foot off gas, clutch in, shift, clutch out, accelerate, all as fast as I could and upshifts were always butter smooth. When just driving around town and shifting at a much lower rpm, I would have to wait a bit for the revs to drop when going from 1st to 2nd to ensure a smooth upshift. I never partially let the clutch out and apply light gas ever (basically slipping the clutch).

The WRX 5 speed tranny though, is a completely different beast. I thought I'd figure it out relatively quickly, but now and I'm realizing there is something I'm probably just not doing right. Normal driving around town is pretty easy to keep upshifts smooth, since it's never a race, and waiting for the revs to drop to get a smooth upshift is never a problem. The problem comes when I want to drive a little quicker, and want to do some quick upshifts....

The revs on this car drop incredibly slow! In 1st gear, if I shift at 4k rpm, I've found that I need to pop the clutch out between 2.6-2.9k rpm to get a smooth upshift. That's almost half the revs dropping! Anything else and the car jerks. A car that violently jerks under hard acceleration is a recipe for disaster if control is the goal. Of course if I let the clutch out nice and slow and apply a little gas things get smooth, but that wastes even more time on a track, let alone not great for clutch longevity.The drop in revs takes a good full second to happen, totally unacceptable if fast gear changing in the key. I don't remember how much I need to let the revs drop from 2 to 3, and 3-4, but they are very slow as well.

I am hoping that I am totally missing or not getting something, and there is a way to upshift quickly and smoothly without slipping the daylights out of the clutch. Thanks for reading, and looking forward to becoming a contributing member to these forums.

[oguitar]

WRX's are a strange car when it comes to shifting. I am not sure how the new WRX's feel but in my 8 year old bugeye I have learned that you got to give the car a little less gas right before you shift. I really don't know how to put it in words. In my car I normally see REV's go up as I shift. Maybe something has changed.

Is the Lotus turbocharged?

[catinthehat]

The Lotus is a supercharged 6 speed. The WRX is my first turbo car. I think what you are saying is, to start letting off the gas sooner before the shift, and do it more slowly? I have not tried that yet.

[djclue8713]

Subscribed. I also don't want to fry my clutch by slipping it. Shifting in this car is an art, and I want to perfect it.

[teflon_jones]

My new STI is hard to upshift smoothly when driving aggressively too. I'm used to my 911 where you shift as fast as you can when you're pushing it and it goes perfectly. I'm still having issues getting my STI to do the same thing, or at least somewhat similar.

[catinthehat]

My new STI is hard to upshift smoothly when driving aggressively too. I'm used to my 911 where you shift as fast as you can when you're pushing it and it goes perfectly. I'm still having issues getting my STI to do the same thing, or at least somewhat similar.

Exactly. In my Lotus, I would even say that if you don't shift very quickly, then the car jerks because the revs fell too fast. Upgrading to a very short throw shifter in that car was necessary. I ordered my WRX with the factory short throw, but aside from shifter feel, I am currently not seeing the shift throw to be close to the limiting factor here.

[msharp]

My new STI is hard to upshift smoothly when driving aggressively too. I'm used to my 911 where you shift as fast as you can when you're pushing it and it goes perfectly. I'm still having issues getting my STI to do the same thing, or at least somewhat similar.

Same story. I came from an RX-8 and the shifting was just perfect --- as fast as I want and smooth as butter. Now, after driving the '11 WRX for a few months, I realized how slow the needle drops... some times I even wanted to change to a lighter flywheel but my wallet won't agree with me...

Anyways, subscribed.

[Stlgrndskeeper]

Upshifting during hard acceleration into 3rd seems a little tricky at times in my 2011. If I slow the shift process down a bit and really concentrate on clutching in before moving shifter at all (no anticipation nudge) that seems to cure it.

[msharp]

Okay, I *think* I have some theories about this, and everyone please feel free to correct me.

1. The WRX is supposed to take longer to shift, compared to any car that is equipped with close gear-ratio transmissions. This is simply because the gear ratio on the WRX is larger, and naturally it'll take more time to match the RPM for the next gear.

2. The WRX has a heavier flywheel which has some advantages. But the down side is that it slows down the RPM change, so you can't really shift too fast.

3. Every transmission will have an ideal shifting rhythm, which is determined by the mechanical nature. Even when you're driving spiritedly and shifting at redline, the shift time should remain about the same. There's a certain window in which you can shift smoothly. If you shift faster than its natural shifting rhythm (above the window and the RPM is still too high), the car will jerk; and if you shift too slow (below the window and the RPM dropped too much), it wouldn't be smooth neither. So in other words, there can't be just some kind of tip for you to shift quicker than the mechanical rhythm. If you want it to be quicker, you'll probably have to do some upgrade.

Those are just my "hypothetical theories", please feel free to comment (or flame). :-)

[poly_poly-man]

1. Yep, that's part of it. Also the rotational inertia of anything before the clutch, and the fact that AWD does not mix well with shifting early (think rear diff clunk - when the engine is going faster than the wheels and you clutch dump, even when shifting).

2. heavier than what? it's pretty heavy, but not too heavy. Basically, heavy->drivability, light->raceability. Lighter flywheels make it harder to do rev-matching tricks, and make regular lazy shifting a bit harder, but will make your shifts faster, and most importantly reduces rotational inertia of the driveline, which is like lightening the car (has nothing to do with shifting, but it'll make you quicker). Basically, it makes the engine change revs quicker, both up and down.

3. Sort of. I don't believe it's constant, just because of all the squared-terms in the rotational energy equations, but yes, for a given situation, a car will only want to shift so fast. You take your foot off the gas, you put your foot on the clutch, and then it's a given time before the engine rpm will be low enough to accept the next gear. If you screw up and leave your foot on for too long, it'll make it longer, etc. but if you do everything right, the car's the limit. Again, though, this certainly isn't the same for every gear change (different ratio differences), and I don't even think it's constant fror every situation in a particular gear change (the engine has to lose a particular amount of energy to get from one rpm to another. At a given speed, the rpm at gear x and gear y will be related by a constant multiple. To lose energy (proportional to rpm^2), assuming a constant (or at least not quadratic) frictional force.... yeah, it takes slightly different amounts of time. It should be... (lemme see if I'm thinking straight) a little less time to shift if you shift at an earlier rpm.

...of course, the tradeoff is that you don't get your precious hp peak.

You're getting somewhere with your ideas. And that somewhere is that you should really invest in a lightweight flywheel

[mangostick]

1 .. yeah kinda.. but the wrx flywheel is heavy.. all oem flywheels are heavy in the class of car we have.
also cant compare a effing lotus to a wrx.. they're not even close to the same class let alone quality.

2 light flywheel HELPS rev matching and shifting.. it allows the engine speed to be easier manipulated to match ground/driveline speed. ..now in daily driving yes a light flywheel will make stop/go driving a bit more work intensive.

3 yes.. one has to be patient when shifting one of these cars in factory condition. There are a couple of factors (aside of the math but related to) .. Now, the heavy flywheel and crank pulley are definitely contributing factors in how slowly the car revs back down between shifts/throttle application. There is another catch that I personally have a huge problem with.. the effin ecu is MAPPED to keep the throttle open a touch after clutch/throttle dump. Its for emissions and its annoying as hell. I've been driving manual trans cars of all varieties for 17 years and I know well my timing is dead on.. still the car has this odd rev hang after throttle lift. I've heard that tuning takes this out.. but have yet to confirm it.

[Stlgrndskeeper]

I loaded the Cobb stage 1 map Saturday night and one of the things I noticed was how much more smooth my shifts were even under hard acceleration. I can't confirm that it was something that Cobb purposely put in the stage 1 tune, but I can tell you that the shifting is much improved.

[msharp]

@Stlgrndskeeper,

Now that's GREAT news! Much more affordable than the flywheel upgrade I'd say. :-)

[msharp]

the effin ecu is MAPPED to keep the throttle open a touch after clutch/throttle dump. Its for emissions and its annoying as hell. I've been driving manual trans cars of all varieties for 17 years and I know well my timing is dead on.. still the car has this odd rev hang after throttle lift. I've heard that tuning takes this out.. but have yet to confirm it.

Would this be one of the reasons why the Stage 1 improved shifting? Maybe the stage 1 map removed or minimized the throttle delay after throttle dump?

[djclue8713]

If this is true, add that to the list of reasons for me to spend $ on an AP. Can anyone else confirm this?