What is really the problem using a beetle as a drag racer?

[Ragtop]

Something else to consider is wheels,how many cars use thin alluminium dished wheels? I wont use the common name as thats not actually who makes them.When you go to chevy pattern[the most common non vw] which is alot smaller than wide 5 the wheels have the ability to flex alot more,add 500+hp and a car that moves around,at what point does the wheel flex? then to look different you decide to get a pattern cut into the wheel[star cut etc] now it is really likely to flex.
There is a reason they make SFI certified wheels

When you start to add up all those little things[steering angle change,rear camber and tow change,wheel flex,chassis flex,weight bias wrong etc] its amazing anyone gets down the track at all    

Damn Richie when you put it like that it sounds almost dangerous what we do 

[richie]

Damn Richie when you put it like that it sounds almost dangerous what we do  

Nah,its just exciting,just like being at the fairground on a ride and seeing one of the main fixing bolts is loose,you know sooner or later its going to crash/fail but you cant help having another go



For those of you that havent seen these 2 cars run,the benifits of clutchless shifting can be seen


1st the Black mamba rotary engined with mendeola trans bug testing clutchless shifting form 3rd to 4th gear,1st  - 2nd shift will be clutchless soon



<a href="http://www.youtube.com/v/L-ka1OtWBU8" target="_blank">http://www.youtube.com/v/L-ka1OtWBU8</a>

2nd Brazilian sequential shifted turbo new beetle

<a href="http://www.youtube.com/v/qmksGJH-0Pc" target="_blank">http://www.youtube.com/v/qmksGJH-0Pc</a>

 http://youtu.be/qmksGJH-0Pc

[Patte]

It looks like the new Beetle is using the clutch.
Another benefit with clutchless shifting is that it usually knocks off 3 tenths in a quartermile 

[richie]

It looks like the new Beetle is using the clutch.
Another benefit with clutchless shifting is that it usually knocks off 3 tenths in a quartermile 

having watched it again it does look like his clutch foot moves on some shifts,from the outside if the car video it looks very smooth as it changes though,I cant see my car hitting that bump and staying the right way up

Have you figured out a way to allow yours to dissengauge the gears without the clutch?

cheers richie

[Patte]

[/quote]

having watched it again it does look like his clutch foot moves on some shifts,from the outside if the car video it looks very smooth as it changes though,I cant see my car hitting that bump and staying the right way up

Have you figured out a way to allow yours to dissengauge the gears without the clutch?

cheers richie
[/quote]

It sure looks smooth and fast,especially on that bumpy track,they have had couple of nasty accidents with VWs there lately 

Fredde is looking at buying the Finnish gears without heat treatment and make some changes close to the G-force clutchless system 

I have given up on trying to make it work  and just flatshifting it with just touch on the clutchpedal
Without boost,driving it like an NA its noproblemo just move the shifter and there it is  and down shifting is also slick,but who cares 

//Patte

[Basti]

In my opinion its all about the X-Weight and the shifting....

My gearbox is converted to full sequential....
If anyone is interested as well....let me know

Cheers,
Basti

[Jon]

I think that another big issue is the need for heavy springs and shocks we need to handle
the launches,making it to stiff when we go down the track and making the tires take most of
the hits when it becomes a bit bouncy.
The V8 promods uses electronic shocks to adress this problem,setting them stiff at the start
and looser down the track.Expensive? yes, but maybe worth it

//Patte

I had an idea yesterday about this, what if you ran softer shocks on the rear, and installed an air cylinder right next to it, like the dual shocks you see on Baja bugs.
This cylinder would contain some pounds of pressure and act as support shock. Its there during the start and starts to bleed out thru a electronically operated valve as you hit second or third gear... by fourth the car would be in its softest mode again...
Just throwing it out there... 

[richie]

In my opinion its all about the X-Weight and the shifting....

My gearbox is converted to full sequential....
If anyone is interested as well....let me know

Cheers,
Basti

Yes I am interested,how does it work? have you driven it?

cheers richie

[Jon]

A funny thing I found on ground effects on formula 1 cars:
"There are legends of a BRM "ground-effects" car designed by Tony Rudd in 1969, which was never built, but I would regard the 1977 Lotus 78, indeed largely designed by Rudd and Peter Wright, to be the first ground-effects car.

For the first time, air was invited to the underside of the car in order to create higher air-speed and lower pressure through the "Bernoulli-principle", where higher dynamic pressure (Rho*v^2/2) leads to a lower static such.

Before the Lotus 77, racing car designers were largely pre-occupied with preventing air from getting under the car."

http://www.f1technical.net/forum/viewtopic.php?f=6&t=7880

[Basti]

Hi Richie,

the gears are changed to dogrings and the shifting mechanics are changed as well.
So you just pull on the leaver. Gearcut and gearposition for ECU Strategys can be added.

Yes i drove it in a hillclimb beetle with big Typ 4 and 5 gears.

My Mendy is in build now and I will test it next spring in my car...

Cheers,
Basti

In my opinion its all about the X-Weight and the shifting....

My gearbox is converted to full sequential....
If anyone is interested as well....let me know

Cheers,
Basti

Yes I am interested,how does it work? have you driven it?

cheers richie

[Fasterbrit]

I see Russ Fellows has come even closer to an '8' with his 9.18 - all this with a stock floor pan, stock VW IRS design and some playing around with aerodynamics. 155 mph and very stable. Russ's car is proof that if you pay attention to airflow you can make a stock body shape work at speed. I guess not lightening the front end probably helps in his case, too.

It would be absolutely awesome if he breaks the 8, especially as its a street driven car.

[Jyrki]

OK, got the new car weighted today, though it is still missing the body, wheelie bars and chute. We estimated how the weight of the body distributes between front and rear and came up with 57-43 weight distribution race-ready. There is only 43kg of ballast in the front now – I will most likely add more.

[ Attachment: You are not allowed to view attachments ]

Anyway, it seems we all agree that any drag race beetle should have all the basic things done (for example complete alignment through suspension travel), and as one approaches the 9 and 8 sec zone aerodynamics and weight distribution of the beetle makes it a poor basis for drag racing. Since we can’t totally fix the root problems, we have to come up with a good design of the chassis/suspension/aero and address details that are not relevant to other makes and models running same et’s and speeds.

Jyrki

[Neil Davies]

Have we got any video footage of beetles either crashing or getting out of control? It would be really interesting to see which end starts to get light. The lightweight front end makes you think that the front would lift and start to wave about, but the wing shape of the beetle body makes you think about the car generating lift and the back end lifting. Do we really know how a beetle crashes?

[JamieL]

What about the weight transfer when drivers lift off after crossing finish line? The relationship between the relevant positions of centre of mass and aero centre of pressure are critical considerations for vehicle stability....

Not helped by nose-down stance either...

I know some racers/drivers use different techniques in relation to throttle/clutch/brake when running through the top end and lifting, but I guess we will never know what happened in actual crash circumstances...

For more info/theory concerning aerodynamics then there's lots of goodness, not to mention a bloody good read, at www.bloodhoundssc.com
(might take a while for people to find the right bits so enjoy dyor)

[richie]

i have been cornerweighting my car today after several changes

I ended up with total 1956lbs with fuel tank fuel,driver with racesuit,helmet etc  and the best i have been able to get it is

37/63 front to rear weight bias with 50lbs lead right at the front of the car,more lead passenger side opposite my feet,and another block of lead passenger side behind the firewall which offsets the dry sump tank.
I have worked quite hard on placement and materials to try make it better,I need to find some more lead now to put up front to help some more

My conclusion is they would be much better if we didnt put a driver in the car

cheers richie

[Erlend / bug66]

What about in the middle? 

[BeetleBug]

What about in the middle? 

Nah... it hurts so dam much if you experience a sudden stop.

[Jon]

i have been cornerweighting my car today after several changes

I ended up with total 1956lbs with fuel tank fuel,driver with racesuit,helmet etc  and the best i have been able to get it is

37/63 front to rear weight bias with 50lbs lead right at the front of the car,more lead passenger side opposite my feet,and another block of lead passenger side behind the firewall which offsets the dry sump tank.
I have worked quite hard on placement and materials to try make it better,I need to find some more lead now to put up front to help some more

My conclusion is they would be much better if we didnt put a driver in the car

cheers richie

Did you find you find center of gravity at the same time Richie?

Here is a nice calculator to find it: http://www.longacreracing.com/articles/art.asp?ARTID=22

[Martin]

just going back to the "aero" side of the subject.

I have downloaded all the logs from my car at bug jam.

car back ground -  back half car, swing axle koni double adjustable dampers and 800lb springs with 10 mm of preload. 2200lb with the fat driver and full tanks a spot on 60/40 split.


the DATA ive been looking at the most is the suspension..

test 1) no front air dam or rear 'Keno wing' anything past 135 -140 and the car is lifting at the front and rear, enough to not know which way the car wants to go

test 2) front air dam fitted. easy drive past 145 the car is lifting very slightly at the rear, the front is lower than without the Dam, car feels good 2 still want 2 hands on the wheel though.

test 3) Front air dam and 'keeno wing' fitted, front suspention is extending to the same amount as the previous runs, and the rear is slightly lower (2-3 mm) car feels fantasic, one hand on the wheel with no concern at all


what i can conclude from my personal findings are:


the front air dam is stopping too much air getting under the car, and the rear wing is just breaking up the air trailing from the roof, as the extra down force was minimal. but the spill plates on the sides are taller than usual 'keno wings' and i personaly feel that this is giving extra strait line stability to the car (bit like a rudder)

so the next outing we shall be turning up the power to push through the 150, and re visit the chassis data.



just as i side note Russ Fellows's car was going though the top end at 155mph running his front air dam and a small rear wing (most of its an oil cooler) and he felt it was rock solid. mind you he is complaining that its harder to make the first turning now

Martin

[richie]

i have been cornerweighting my car today after several changes

I ended up with total 1956lbs with fuel tank fuel,driver with racesuit,helmet etc  and the best i have been able to get it is

37/63 front to rear weight bias with 50lbs lead right at the front of the car,more lead passenger side opposite my feet,and another block of lead passenger side behind the firewall which offsets the dry sump tank.
I have worked quite hard on placement and materials to try make it better,I need to find some more lead now to put up front to help some more

My conclusion is they would be much better if we didnt put a driver in the car

cheers richie

Did you find you find center of gravity at the same time Richie?

Here is a nice calculator to find it: http://www.longacreracing.com/articles/art.asp?ARTID=22

Hi Jon,

no nothing like that,making a solid bar to replace the front strut might prove difficult for me as well

[JamieL]

mind you he is complaining that its harder to make the first turning now

LOL 

And no doubt still using the same burnout braking technique...  

[Airspeed]

Good info Martin!
Thanks for sharing.

[Martin]

mind you he is complaining that its harder to make the first turning now

LOL 

And no doubt still using the same burnout braking technique...  

Yep, he is     lmao

[dannyboy]

bear in mind i know nothing about chassis design but formula v cars flip the diff and run the motor mid mount would this not help balance out the weight in a tube chassis car?
i think there would still be plenty of room behind the seat to fit it in? 

would be interested to hear why this is a no no 

[richie]

bear in mind i know nothing about chassis design but formula v cars flip the diff and run the motor mid mount would this not help balance out the weight in a tube chassis car?
i think there would still be plenty of room behind the seat to fit it in? 

would be interested to hear why this is a no no 

might as well put it in the front then as its not a VW as I know it after that  

Getting real data for a rear engine VW is rare enough,getting data for a mid engined version is non existent making it even harder

cheers richie

[Fasterbrit]

Great info Martin. It's nice to have hard evidence to back up the 'seat of the pants' theory. Hopefully people will take note of your experience and apply it to their projects if they intend going faster than 125 mph. That tends to be the 'magic' number when things get hairy on a Beetle.

[Stripped66]

Have we got any video footage of beetles either crashing or getting out of control?

Good luck...it seems all videos of VW crashes share the same hand-steadiness as recorded UFO sightings. You'd think it was an earthquake that causes the crash.

It would be really interesting to see which end starts to get light. The lightweight front end makes you think that the front would lift and start to wave about, but the wing shape of the beetle body makes you think about the car generating lift and the back end lifting. Do we really know how a beetle crashes?

It pains me to say that it would be very informative for a car that datalogs suspension position/steering position to crash. How much of the problem is strictly aerodynamics versus inappropriate driver input or overreaction. FWIW, and just my opinion, the use of small-diameter steering wheels worries me. These are not long-wheel base cars that are slow to react to quick steering inputs; we drive short-wheel base cars that are going to quickly respond to quick steering inputs.

[BeetleBug]

How much of the problem is strictly aerodynamics versus inappropriate driver input or overreaction.

What do you consider inappropiate driver input or overreaction? It is not like we`re trying to do a slalom run. We`re just trying to go as straight, and fast, as possible and you do not need to turn the steering wheel before something tells you that it is about time to do so. Yes, a slick can give you "false" input meaning that it sometimes feels like the rear end is moving more than it actually do.   

FWIW, and just my opinion, the use of small-diameter steering wheels worries me. These are not long-wheel base cars that are slow to react to quick steering inputs; we drive short-wheel base cars that are going to quickly respond to quick steering inputs.

I do not agree. The car "feels" more "nervous" with a bigger steering wheel and this can caouse inappropiate driver input. I think a old drag racer told us to go with the flow somewhere in this thread. There is cars with shorter wheelbase doing 6 second runs with a tops speed of 190 mph and you do not see them use a truck size steering wheel.

[richie]

I do not agree. The car "feels" more "nervous" with a bigger steering wheel and this can caouse inappropiate driver input. I think a old drag racer told us to go with the flow somewhere in this thread. There is cars with shorter wheelbase doing 6 second runs with a tops speed of 190 mph and you do not see them use a truck size steering wheel.

Mmmmm,thinking about this,my theory with the stock size steering wheel was more wha i was used to from the old cabrio,I ended up with a same size wheel and same amount of turns lock to lock so in theory I should have the same input to what I am feeling,the factthat the car behaves so diffferently to steering input kind of threw that idea out the window.
Maybe the next improvements will include a smaller wheel,[and put it on the other side ]

as for the cars running 6s with less wheelbase,how many are clutch cars,one thing that I really noticed is my natural instinct to move the steering wheel slightly everytime I change gear,auto trans would take this away?


cheers richie

[stretch]

I do not agree. The car "feels" more "nervous" with a bigger steering wheel and this can caouse inappropiate driver input. I think a old drag racer told us to go with the flow somewhere in this thread. There is cars with shorter wheelbase doing 6 second runs with a tops speed of 190 mph and you do not see them use a truck size steering wheel.

Mmmmm,thinking about this,my theory with the stock size steering wheel was more wha i was used to from the old cabrio,I ended up with a same size wheel and same amount of turns lock to lock so in theory I should have the same input to what I am feeling,the factthat the car behaves so diffferently to steering input kind of threw that idea out the window.
Maybe the next improvements will include a smaller wheel,[and put it on the other side ]

as for the cars running 6s with less wheelbase,how many are clutch cars,one thing that I really noticed is my natural instinct to move the steering wheel slightly everytime I change gear,auto trans would take this away?


cheers richie

With regards to the steering wheel debate, I had a problem this year on the Sunday morning at Bug Jam.  The car was running fine all weekend, but, Sunday morning I went out first run & the back end of the car felt all over the place.  I got back to the pits convinced that i'd broken something.  I checked the car over, couldn't find anything wrong, went out again, same thing (although not quite as bad this time).  Weird.  Thought i'd give it one my try, it was on this run that I realised I was holding the wheel in a different position than I usually do (3 o'clock as opposed to usually around 12 o'clock) everytime I shifted gear i'd yank the wheel to the right.  This was obviously upsetting the car.  Next run I consciously held the wheel at about 12 o'clock, no more problem.

It's amazing what little things can do.  How many of us think about tyre pressures with one side of the car sitting in direct sunlight, especially if there's an oil down or some other delay on the track.