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

[ChimpMania]

Originally Posted by Subie

I'm pretty sure at this point that the throttle works as it ought to; i.e. good throttle response and no rev-hang. With that said, if I notice differently, I won't be buying a BRZ. It's one of the main reasons I'm getting rid of my tC. The throttle response is crap at best, and the rev hang is hugely annoying.

this guy said he won't be buying a brz...profile says drives brz lol looks like he did end up buying it

[Tcoat]

Originally Posted by ChimpMania

this guy said he won't be buying a brz...profile says drives brz lol looks like he did end up buying it

Considering he hasn't logged on in over 4 years who know what he drives now.

[extrashaky]

Well, since this thread has been resurrected anyway:

I loved the way the revs in my old Triumph would dive, and I was a little disappointed that the high compression motor in the BRZ didn't have that same snarl. So the question is, can it be tuned out (safely), or is it a mechanical byproduct of the engine layout or crankshaft design? Do any of the off-the-shelf tunes improve it?

[gramicci101]

Originally Posted by extrashaky

Well, since this thread has been resurrected anyway:

I loved the way the revs in my old Triumph would dive, and I was a little disappointed that the high compression motor in the BRZ didn't have that same snarl. So the question is, can it be tuned out (safely), or is it a mechanical byproduct of the engine layout or crankshaft design? Do any of the off-the-shelf tunes improve it?

If you want your RPM to drop more quickly, get a lightweight flywheel. Reduced rotating mass carries less inertia and so will be more susceptible to quick changes in RPM. You need to be on point with your shifting though.

[ChimpMania]

Originally Posted by Tcoat

Considering he hasn't logged on in over 4 years who know what he drives now.

mustang..it's always a mustang

[RedFRS4me]

My G35 coupe 6mt had terrible rev hang vs my frs. No worries lol

[extrashaky]

Originally Posted by gramicci101

If you want your RPM to drop more quickly, get a lightweight flywheel. Reduced rotating mass carries less inertia and so will be more susceptible to quick changes in RPM. You need to be on point with your shifting though.

I have seen videos of the difference in revs with a lightweight flywheel, and it still has more rev hang than I would expect. My Triumph backed off like the Mustang in Bullitt. It had ZERO rev hang. The lightweight flywheels don't appear to make much of a difference in comparison. (Not that I want it to sound like a Mustang.)

[ame="https://www.youtube.com/watch?v=31JgMAHVeg0"]Bullitt - The Chase (part 1) - YouTube[/ame]

[JohnnyK]

Originally Posted by extrashaky

My Triumph backed off like the Mustang in Bullitt. It had ZERO rev hang.

And my mustang has 'rev hang', because, it has the ECU for a manual transmission car.


Or you could slap a carb on your brz and learn to tune!

[extrashaky]

Originally Posted by JohnnyK

And my mustang has 'rev hang', because, it has the ECU for a manual transmission car.

Since I do so love conversations that go around in circles for no reason, this brings me back to the question I asked initially: If the rev hang is a product of the ECU, can it be tuned out (safely)? Do any of the off-the-shelf tunes improve it?

[Xxyion]

Originally Posted by extrashaky

Since I do so love conversations that go around in circles for no reason, this brings me back to the question I asked initially: If the rev hang is a product of the ECU, can it be tuned out (safely)? Do any of the off-the-shelf tunes improve it?

I think the OTS tunes on the OFT get rid of it. Personally never really noticed as me previous MT car was a Ford Fiesta with terrible rev hang. And my new Fiesta ST suffers from this as well. It's to the point that its actually harder to keep my BRZ at a high speed because i tend to lift my foot a bit when i start cruising.

I am however boosted and so my speed and RPMs drop drastically when i lift my foot off and thats most likely due to the tune i'm running right now.

[JohnnyK]

Originally Posted by extrashaky

Since I do so love conversations that go around in circles for no reason, this brings me back to the question I asked initially: If the rev hang is a product of the ECU, can it be tuned out (safely)? Do any of the off-the-shelf tunes improve it?

I am not sure if this is directed me, but my answer is "I don't know"


On my Mustang, it can be dealt with, but that is a much older FI system, and for the life of me, I can't even remember how. I mean there isn't a parameter called "Rev Hang". I think it was by messing with the IAC circuit or some such.

[extrashaky]

On second thought, it's probably best not to mess with it. My stock, perfectly maintained 65K mile BRZ made a pop and clatter yesterday that sounds exactly like the descriptions I've read here of a spun bearing. If the stock motor won't even stay together, I think maybe I'll pass on modifying it.

[Captain Snooze]

But then the potato gets ear waxed.

[aquasurf]

Originally Posted by extrashaky

I have seen videos of the difference in revs with a lightweight flywheel, and it still has more rev hang than I would expect. ....... The lightweight flywheels don't appear to make much of a difference in comparison....

It should come as no surprise that weight of flywheel cannot have much effect on reducing rev hang caused by injectors feeding fuel to the engine for some time AFTER the throttle was closed. The role of flywheel is to resist change. With the rev hang maintaining revs, there is no call on the flywheel (light or heavy) to do anything. Only when the rev hang stops, then a lighter flywheel will make the revs drop faster. Well, it is like shutting the gate after the horse has bolted.
I managed to remove revhang in 4 different car models I owned by fitting my own QREVS device. You can google it.