Toddler...I'm getting a bad vibration...........

[retro]

http://seven.com.au/news/sport/97324

Kelly racing with hampered V8 vision
Date: 02/08/05
By Todd Balym



V8 Supercar driver Todd Kelly has revealed a problem in his car causes him to have obscured vision when his Holden is at top speed.

Vibrations through Kelly's helmet means he sometimes loses vision along most circuit straights when his car hits speeds upwards of 250km/h.

The consequences of having such a problem are diabolical.

Yet despite this problem, which he has carried all season, Kelly has won races in Shanghai and Darwin and is having his best season to date, currently fourth in the championship.

The China result was particularly exceptional considering it was his first time to the track and the circuit has two very long straights.

"There's a vibration we've had all year that we've been chasing," said Kelly after a test session around Phillip Island on Monday.

"It's been going through the rollcage and knocks my vision around a little bit.

"It's speed related, the faster the car, the more the vibration, and it was really troubling me in China with those long straights."

Both Mark Skaife and Jim Richards confirmed the vibration after driving Kelly's car at the session.

While Kelly has found the problem manageable it is concerning as his hampered vision along the straights makes it more difficult for him to pick his braking markers.

"It's hard to find kerbs and apexes sometimes because everything is vibrating," he said.

"It's one of those things you just put up with in races, but it would be nice to get rid of it."

Despite a day of testing the problem was not found and the Holden Racing Team will now strip the car in a bid to rectify it before next weekend's Oran Park event in Sydney.

The rescheduled testing session - HRT had planned to test before the Queensland Raceway event last month but poor weather forced it to be postponed - has enabled the team to iron out a few other minor problems with the VZ Commodores of Kelly and Skaife.

"We've gone through a heap of things and a lot of them aren't really relative to a lap time," said Kelly.

"We're concentrating on certain parts of the track to test certain things.

"Mark (Skaife) jumped in and had a drive of my car for the first time, and it was really valuable to get another opinion, all of his feedback made a lot of sense."

With six rounds left in the championship, including two team endurance races, Kelly trails Ford leader Marcos Ambrose by 134 points while Skaife is considered a title long shot 212 points adrift.

Copyright © 2005 AAP

[Raglanparade]

Maybe it explains his shaky start to the season.

[James63]

Originally Posted by jasonhill9884

Maybe it explains his shaky start to the season.

[1200Datto27]

Vibrations like that are normally related to rotating mass within in the car, it seems strange that it would still be there after having (surely) lifed all of the rotating components. Be interesting to see if they say what the cause was.

[kramer]

Originally Posted by 1200Datto27

Vibrations like that are normally related to rotating mass within in the car, it seems strange that it would still be there after having (surely) lifed all of the rotating components. Be interesting to see if they say what the cause was.

Yeah - you're right. But I wonder if it's not a resonance caused by aerodymanics? There could be a pressure wave thingy going on - not noticeable at lower speeds. A large body like that punches a big hole in the air - something could be causing almost a sonic boom effect at the back of the car or behind the rear screen - I'd imagine that could set up a horrid vibration.

I once had a car that had a horrendous resonance in the exhaust - only at 60kays in 4th - the same revs, throttle opening, road speed, whatever, in another gear no problem- only in 4th.



Kramer

[pete55]

Originally Posted by kramer

Yeah - you're right. But I wonder if it's not a resonance caused by aerodymanics? There could be a pressure wave thingy going on - not noticeable at lower speeds. A large body like that punches a big hole in the air - something could be causing almost a sonic boom effect at the back of the car or behind the rear screen - I'd imagine that could set up a horrid vibration.

I once had a car that had a horrendous resonance in the exhaust - only at 60kays in 4th - the same revs, throttle opening, road speed, whatever, in another gear no problem- only in 4th.



Kramer

Austin A40's were notorious for that.

[1200Datto27]

But why would Todd's do it if it was aero based, and not any other Holden? are they not all supposed to comply with templates?

[Kerri]

Now that's funny Pete.

[kramer]

Originally Posted by pete55

Austin A40's were notorious for that.

What? Aerodynamic vibrations???? You have to have some forward speed for it to be an issue. And no, it was a Gemini, actually. But I'm reminded of a vibration in a car my Grandfather had. It happened from 40mph to about 45mph - not such a huge problem except that 45 was its top speed.

1200 - no two cars would be the same - look at the huge difference a small thing like a Gurney flap makes - so I reckon it could be any number of bodywork shape issues at fault.

Or maybe this is HRT's first dedicated short-track car?



Kramer (never owned an A40 - but did have an 1800)

[Razor]

Mabey Todd's helment is possibley hitting some of the roll cage tubing, and here is an experiment to prove it, if you are in a car travling at 60kph, put your head on a part of the door your next to and then see if you can get the car to go to 100kph and if it is at 100kph, your head gets a bad vibration and you vision gets blured and knocked around.

[DKGandBH]

Time to take the roof racks off...

DKGandBH

[SRabbit]

Todd should employ a tactic Webber had to use earlier this year when he flatspotted the 2 fronts and when going down the front straight at 300 he said he could barely hold onto the wheel let alone find the brake marker from shaking, basically driving the straight blind, so they had a spotter on his marker who would get on the radio and say 'NOW!!' and thats when he'd get on the picks for the corner - brave, or stupid??