Does the BRZ/FR-S suffer from rev hang?

[OrbitalEllipses]

Originally Posted by serialk11r

That's good to hear.

All cars have it these days, it's to reduce HC emissions. When the engine decelerates quickly I'm guessing there's a bit of "ECU lag" because the sensors aren't picking up on the decreased airflow immediately, and you end up having excess fuel injected which comes out the tailpipe in the form of black smoke or a fireball + black smoke. I think that's the reason some cars have that fireball or puff of smoke come out when they shift gears.

mmm uncatalyzed hydrocarbons exploding is my favorite.

[dookie11]

Gosh, learned another new thing about cars today. You guys always make my daY

[Hanzo]

Sounds like it has something to do with heavier flywheel to save gas.

[(K)]

Our 2003 2.4L Solara (not the '99 I'm driving now, different drivetrains) had some rev hang. It wasn't terrible, but noticeable. Definitely an emissions related "feature". This was with it's drive by wire system so it was pre-programmed and electronically controlled. Once the cat (not a typo) warmed up after a few minutes of driving, the rev hang would either disappear altogether or was reduced greatly. I don't remember it affecting throttle-blipped downshifts or downshifts in general, mostly upshifts. Fast shifts were still smooth during WOT so I believe rev hang is negated on WOT but don't quote me on that.

We might want to move this into the technical section because I'm fairly certain it has to do with air/fuel control and folks with more experience in those areas would be able to clarify and expand upon the subject. I'm not sure if it's all throttle related, timing related, or a combination of all of the above and black magic. I would like some clarification, myself.

[MmmHamSandwich]

As a Civic Si owner, I'll be supremely aggravated if the 86 series has rev hang. Even if all you want is the rev hang gone on a civic, you have to pony up for a FlashPro.

It's obnoxious and a detriment to the car. I've heard people praise the BRZ's throttle response, hopefully that includes lifting as well.

[engee]

I didn't really pay particular attention to revhang when driving the BRZ. However, I didn't notice any rev hang. Rev matching, heel toe, and normal shifting felt good. I can't give any definitive answer but the car felt fine during the test drive.

[Lighting Red]

Hmm... I didn't recall any rev-hang when I drove the car. I would have noticed something like that.

[Subie]

I really appreciate the feedback so far! I think the consensus is that Toyota/Subaru haven't mucked around with the go pedal.

[Kimsey47]

Originally Posted by Subie

I really appreciate the feedback so far! I think the consensus is that Toyota/Subaru haven't mucked around with the go pedal.

With all the comments of people not very impressed with the fuel economy of the car (I am fine with 30mpg hwy), perhaps it has to do with that attempt to avoid the rev hang for a even purer driving experience?

[eikond]

I have a similar question.. How heavy does the flywheel feel? Does it slow revs pretty quickly when you put in the clutch? I've had a coupe cars in the past that seem like the revs just don't want to drop very quickly at all. It drives me nuts. I'm no expert heal-toe shifter, but I definitely like the revs to drop quickly so that I can nearly match revs when I select the next gear. Having a light flywheel allows you to shfit quick quickly and not have to wait for revs to drop or give it a ton of clutch to assist the process.

[Silverhks]

Originally Posted by eikond

I have a similar question.. How heavy does the flywheel feel? Does it slow revs pretty quickly when you put in the clutch? I've had a coupe cars in the past that seem like the revs just don't want to drop very quickly at all. It drives me nuts. I'm no expert heal-toe shifter, but I definitely like the revs to drop quickly so that I can nearly match revs when I select the next gear. Having a light flywheel allows you to shfit quick quickly and not have to wait for revs to drop or give it a ton of clutch to assist the process.

Almost identical question. Heavy rotational mass has a very similar result to the emissions related rev-hang. Car takes too long to drop revs making it harder to shift smoothly and in worst case scenarios making you wait before engaging the next gear.

As such, since no one has mentioned it I believe we can assume the flywheel is not heavy enough to be an issue.

This does not mean I believe a light weight flywheel would not beneficial

[brufleth]

There is probably an engine deceleration schedule in the ECU. Probably isn't just based on the fly wheel on newer cars. Thermal stresses, stalls, etc. We have a decel schedule in the engine systems I work on.

[velocity]

Originally Posted by Subie

That's my feeling as well, but as bothered as I am by my current car's rev hang, I want to hear something definitive.

What is your current car? Just curious, since I doubt it's a BRZ like you claim.

[Subie]

Originally Posted by velocity

What is your current car? Just curious, since I doubt it's a BRZ like you claim.

2011 Scion tC. How do you know I don't drive a BRZ? Maybe I'm friends with people in high places.