Username:   Password:   Log me on automatically each visit  

Register



Author Message
Giblet
PostPosted: Wed Nov 04, 2009 2:55 am 
User avatar
Professional
Professional

Joined: Mon Mar 19, 2007 12:47 am
Posts: 1340
That makes no sense. :?

Why do you only hear at the time the engine is near it's redline, and hasn't been shifted yet?

There is no reason any car, especially a race car, should start wobbling its tires at the top of each gear, before shifting.

I thought, likely wrongly, that since it was a new noise with V8, we were hearing harsher engine vibration from the higher rev range. This would help explain why it happens before shifting, and why it is longer sounding the higher the gear that it is in.

alelanza
PostPosted: Wed Nov 04, 2009 4:30 am 
Member
Member

Joined: Mon Jun 16, 2008 4:05 am
Posts: 189
Giblet wrote:That makes no sense. :?

Why do you only hear at the time the engine is near it's redline, and hasn't been shifted yet?

There is no reason any car, especially a race car, should start wobbling its tires at the top of each gear, before shifting.

I thought, likely wrongly, that since it was a new noise with V8, we were hearing harsher engine vibration from the higher rev range. This would help explain why it happens before shifting, and why it is longer sounding the higher the gear that it is in.


As I recall it, it took place post gear change, so you´re saying it was just prior to it?


ISLAMATRON wrote:

Tire shake is what the drag racing guys call it but I doubt F1 cars have the torque to enduce that in the higher gears.

Or maybe you are reffering to wheel hop?


Perhaps that may be the right word. Basically the upshift tries to spin the wheels faster but can´t, so the tyre squishes just a bit back and forth, slightly varying the resisting torque in an undampened fashion. I know on normal cars you can feel it with a bit of spirited shifting, i assumed on an F1 having such a relatively smooth shift you can even hear it. But now the other guy says it happens pre shift, so i guess i´ll go watch abu dabhi again.

Alejandro L.
Giblet
PostPosted: Wed Nov 04, 2009 5:06 am 
User avatar
Professional
Professional

Joined: Mon Mar 19, 2007 12:47 am
Posts: 1340
Yeah it's right before, and most noticeable when the camera was facing the drivers face, with the air intake right above it.

The sound you are talking about is actually longer than the time it takes for the transmission to shift gears and already be on the power.

CMSMJ1
PostPosted: Wed Nov 04, 2009 2:36 pm 
Talent
Talent

Joined: Tue Sep 25, 2007 9:51 am
Posts: 290
Location: Sheffield, United Kingdom
Bloody hell! What a random thread... :shock:

Is this not a resonance issue - purely audio pickup and nothing to do with gearboxes, wobbly tyres etc.

Could it simply be that the microphones are being buzzed at certain revs.

Also, the stutters were previously looked at on here and it was agreed generally that this was the transition from one beacon to another as the car moved around the circuits...

IMPERATOR REX ANGLORUM
Giblet
PostPosted: Wed Nov 04, 2009 2:44 pm 
User avatar
Professional
Professional

Joined: Mon Mar 19, 2007 12:47 am
Posts: 1340
These flutters are from years past and unrelated to the recent broadcast problems with transceivers in 2009.

It was only on the Ferrari if I remember, and I did suggest maybe it was a mic problem, but it doesn't seem like it. It seems like the engine goes from full song to slight misfiring. It is however engine note/intake related.

I think the tire wobble thing is rubbish though.

And yeah, what a random thread. Welcome to the world of being on an F1 site in the off season.

It is a curious sound, and if you are not interested, next random thread, right?

tommylommykins
PostPosted: Wed Nov 04, 2009 5:36 pm 
Rookie
Rookie

Joined: Tue May 12, 2009 9:14 pm
Posts: 31
My thoughts:

1) Tyres are universal between the teams. If Ferrari's tyres do it, then why shouldn't anybody else's tyres do it?

2) It is my opinion that tyres are too overdamped and underspringy for the flutter to be being produced there. (after all, you cannot ring a tyre like a bell.)

I would, however, be more happy in seeing the styres as being flexible enough to prevent the mass of the car immediately cancelling out the effect of this flutter, since you do not actually have to accelerate and decelerate the car with the engine with flexy tyres.

3) It is my opinion that the microphones are not malfunctioning (for no reason... it just doesn't look like that to me)

4) Metallic objects resonate quite well... Since so much force is applied to the transmission with modern superquick gear changes, can we not assume that this causes some part of the drivetrain to start oscillating?

Giblet
PostPosted: Thu Nov 05, 2009 1:06 am 
User avatar
Professional
Professional

Joined: Mon Mar 19, 2007 12:47 am
Posts: 1340
Here is what my mind thinks as possible, although probably not plausible.

1 - The size of the intake is the absolute smallest it needs to be to allow the engine enough air to operate at 18,000. Maybe atmospheric conditions "lower the bar", and the motor runs too rich. Unlikely.

2 - Since the motor is right near the RPM limit, maybe the engine was being told to run richer at the same RPM to increas power right before the shift. Ferrari still had their own ECU then so it could have been all sorts of different magic.

3 - As you said, resonance. The v8 is naturally an unbalanced beast compared to the v10, and it's vibrations become worse the higher it revs.

Just not the freakin tires wobbling :)

autogyro
PostPosted: Thu Nov 05, 2009 12:37 pm 
Talent
Talent

Joined: Sun Oct 04, 2009 2:03 pm
Posts: 296
Audible resonance in components within the 'zeroshift' and similar quick shift gear selector/dog clutch assemblies.

Giblet
PostPosted: Thu Nov 05, 2009 1:34 pm 
User avatar
Professional
Professional

Joined: Mon Mar 19, 2007 12:47 am
Posts: 1340
autogyro wrote:Audible resonance in components within the 'zeroshift' and similar quick shift gear selector/dog clutch assemblies.


You going to finish your sentence or just leave us with that? It has nothing to do with transmission types.

Are you actually trying to shift this thread as well into a discussion about the merits of different types of gearboxes?

Blurting about dogs and selectors. I wish f1_eng would pipe up about this one.

bazanaius
PostPosted: Thu Nov 05, 2009 3:10 pm 
Talent
Talent

Joined: Fri Feb 08, 2008 4:16 pm
Posts: 208
autogyro wrote:Audible resonance in components within the 'zeroshift' and similar quick shift gear selector/dog clutch assemblies.


I ate a big red candle.

Life is like a box of chocolates.

other generic phrases containing words.

autogyro
PostPosted: Thu Nov 05, 2009 10:10 pm 
Talent
Talent

Joined: Sun Oct 04, 2009 2:03 pm
Posts: 296
Giblet wrote:
autogyro wrote:Audible resonance in components within the 'zeroshift' and similar quick shift gear selector/dog clutch assemblies.


You going to finish your sentence or just leave us with that? It has nothing to do with transmission types.

Are you actually trying to shift this thread as well into a discussion about the merits of different types of gearboxes?

Blurting about dogs and selectors. I wish f1_eng would pipe up about this one.


Pipe away.
The observed peculiarity is stated as occurring at peak revs over a gear shift.
I am simply referring to the components in use at that specified time.

F1_eng
PostPosted: Thu Nov 05, 2009 10:51 pm 
Member
Member

Joined: Wed Aug 05, 2009 10:38 am
Posts: 59
I'm not 100% sure exactly what you are refering to.

Probably the sound of un-burnt fuel in the exhaust when driver shifts and ignition is cut or retarded for a split second to reduce torque?
Listen to the cars at the track when they use pit-lane limiter, when its activated initially you get a lot of un-burnt fuel before the real limiter kicks in.

Some posts are getting very close to information I don't want to discuss, otherwise I would say some more.

Some very random theories.

010010011010
PostPosted: Fri Nov 06, 2009 12:05 am 
Rookie
Rookie

Joined: Sat Aug 22, 2009 1:41 am
Posts: 33
autogyro: why do yuo feel the need to put zeroshift in brackets all the time, that is its name right?

Probably the sound of un-burnt fuel in the exhaust when driver shifts and ignition is cut or retarded for a split second to reduce torque?
Listen to the cars at the track when they use pit-lane limiter, when its activated initially you get a lot of un-burnt fuel before the real limiter kicks in.


Ya i've heard that alright, makes sense too. thanks!

autogyro
PostPosted: Fri Nov 06, 2009 12:06 am 
Talent
Talent

Joined: Sun Oct 04, 2009 2:03 pm
Posts: 296
F1_eng wrote:I'm not 100% sure exactly what you are refering to.

Probably the sound of un-burnt fuel in the exhaust when driver shifts and ignition is cut or retarded for a split second to reduce torque?
Listen to the cars at the track when they use pit-lane limiter, when its activated initially you get a lot of un-burnt fuel before the real limiter kicks in.

Some posts are getting very close to information I don't want to discuss, otherwise I would say some more.

Some very random theories.


So you wont talk either. Know how you feel.
Very random theories.
Wasting fuel on the pit lane limiter, hmmm, some savings there.

010010011010
PostPosted: Fri Nov 06, 2009 12:35 am 
Rookie
Rookie

Joined: Sat Aug 22, 2009 1:41 am
Posts: 33
So you wont talk either. Know how you feel.


The difference is he hasnt looked for attenion by telling us about what he doesn't want to talk about at every available oppertunity.

Display posts from previous:  Sort by  
Similar topics Forum  Replies   Views   Last post 
No new posts BMW engine Engine, transmission and controls

3

2499

by Tomba View the latest post
on Fri Sep 20, 2002 7:42 pm
No new posts 2004 one engine ruling General chat

10

1605

by ackzsel View the latest post
on Wed Feb 11, 2009 6:12 pm
No new posts Engine problems for Montoya General chat

2

1247

by wrk View the latest post
on Sat Mar 26, 2005 8:16 am
No new posts New 2003 honda engine 1, 2 Engine, transmission and controls

20

6027

by Tomba View the latest post
on Thu Feb 27, 2003 10:06 pm
No new posts engine mappings Engine, transmission and controls

5

2398

by Monstrobolaxa View the latest post
on Wed Jul 16, 2003 4:35 pm
Jump to:  

Who is online

Users browsing this forum: No registered users and 1 guest

Newsletter Ticker SubscribeFollow us
Contact Advertise Contribute Submit news
Donate
Link us
©1999-2009 F1Technical.net 8.2.1 ⁄ Powered by phpBB forum ⁄ Gallery2 photo gallery ⁄ Policy
Webstats4U - Gratis web site statistieken Eigen homepage website teller