I was just having a look on the web at F vee chassis and a number seem to have this weird leading arm setup on the back. I would have thought this would be aweful for bad toe out in corners. Anyone have any info about this setup and why they have it?

Hi Pete
That leading arm suspension has been around for many many years now and is the rule, rather than the exception. Very common, in fact almost universal.
The rationale is that is allows the pivot point of the inner pickup points to be at about the same point as the pivot points of the axles/tubes.
This actually reduces toe changes and resultant bump steering.
With a bit of imagination it sort of mimmicks the operation of a lower "A" arm (kinda)

Its impractical to configure trailing arms to get the pivot points to line up with the axle pivot points hence the leading arrangement.

Also has influence on rear end squat depending on the setup.

Hope that helps
l8tr
E

how does that effect the back of the chassis? does it load it up badly?

Also, I noticed some of the cars on the web aren't using fans for cooling. How does that work? What do you use?

Are your engines balanced? and how? C/W cranks are illegal for the class(?). What's ya rev limit?

If you're gonna turbo ya Vee for hillclimbs what setup are you gonna use, draw through or proper EFI intercooler blowthrough?

Sorry for all the questions, I'm just thinking about designing my motorkhana special based on FV chassis. Tell me if this is not a good idea.

yer it does load up the back a bit but not enough for a drama.
The yanks dont use fans, just ram cooling but in Oz we have to use a 40 Horse upright fan housing.
In 1200cc the engines balanced and really carefully blueprinted. The cam is a specific cam by Wade and we can altewr the timing but about 3 degrees either way seems to be enough. Advance it for grunt and retard it to rev.
The cranks are box stock 40 horse with a minimum crank weight and no CW. There are no retrictions on what is dont to the ports between the valve seats and the carb inlet. Valves are stock.
Top revs depend on valve springs and seating tension but with 70 Lb seat pressure we get about 6300 to 6500 RPM at very best. Most of em around 5500.

The turbo engine is a bone stock 1600 TP that I was given. I was originally going to draw thru a 45mm SU but now I am going to adapt the full EFI setup out of my Pulsar Turbo ET when i went to programmeable EFI.
The entire EFI setup is completely standalone with a few simple connections to make.
The only thing that has to be fitted up really is the ET distributer but this dizzy has the identical diameter to the VW of the part that plugs into the block and its a simpl\e matter of machining an adapter for the bottom of the Nissan dizzy shaft to locate it in the VW dizzy drive!! Yay!
Im useing T3 EFI inlet stubs with appropriate injectors and a single 44mm TB off the ET engine and a garret T02 (non water cooled) turbo which will spool very early on a 1600 and let the engine run out till it lunches itself on low boost (7psi)

I reckon that using a vee chassis would be heaps of fun at a motokhana and make a real good little wagon to play with!
L8tr M8
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[ Edited on 9/11/05 by tassupervee ]

have you got any pics of the chassis setup on ya Vee?
Also, how do you setup the front end so one of the torsion bars acts as an anti-roll bar?

Hi Pete
I dont have any late pix of my suspension setup as I have not finished the conversion to pushrod and bellcranks with inboard shocks and a pushrod operated monoshock rear end.
Once i get more of that done ill post pix of it.

What we do with the front end is to actually remove completely the lower torsion spring pack and replace it with a solid roll bar with the ends machined to suit whichever beam we are using.

I make my swaybars with a straight length of spring steel bar from a springworks and machine up the ends to plug into the chicken legs. 19mm is about the thickest that is practical down to about 15mm or so.
Its a matter of lining it up all straight and welding the ends onto the bar.
The next thing to do is remove the lower dust seals, which sit between the beam ends and the chicken legs, from each side and replace them with machined up brass or aluminium spacer rings.
You have to do this as the swaybar is not retained in the centre of the beam like a spring pack, (or it actually becomes a solid spring), and the lower chicken legs will walk from side to side to the limit of the seal squashing.....Not good!
We usually allow about 10 thou overall clearance to allow the bar to "wind up" when it is twisted and not end up binding. Absolute free running and no "stiction" of the front suspension is a must in a Vee.
These rings are also useful for creating adjustable camber. I have 2 sets made and i simply drill the ends of the swaybar to suit the retaining grub screws for one set and then spin the rollbar 180 degrees, fit the different spacer rings and drill the rollbar again.
This saves having to bend the chicken legs to achieve the -ive camber that works on a Vee.

This way, i have continuous camber adjustment right thru fom about zero to about 8 degrees. Plenty.
This is of course for the BJ beam.
Link pin beams require offset bushes and the like to get major camber adjustments.
L8tr M8
E

nice work tassiev

do you reckon a monoshock setup would work on a rough surface?

also, how stiff is a Vee chassis? will it handle the rigures of khanacross and rallysprint tracks?

how much does your average formula vee weigh?

I'm hoping for a car with a running weight of say 450kgs max...without me in it of course.

Pete

Quote:

I'm hoping for a car with a running weight of say 450kgs max...without me in it of course.

ta, that's what I needed to know. Got my free CAD program. I'll just get my exams over with and start designing then.

oh BTW, have you got any pics of ya gear shifter in the cockpit. I'm wondering how you do all that.

[ Edited on 19-11-2005 by pete wood ]

Pete
Ill get up to the shed and take some pix of the shifter.
Its embarrasingly simple LOL
Ill also get some pix up once the front suspension begins to take shape.
L8tr
E

Now this is strange....

I have two FV chassis' sitting in the shed and most of the parts needed to complete one car...

I have had a long term plan to build one up for hillclimbs, autokhanas and sprints...
On bitumen of course.... (been using my streetcar til now!)
And the funny ting is...I was looking a low boost turbo'd 1600 too!
One day, one day....
Looks like Ill be chatting to you again TSV...
You've been a wealth of information for me and my projects....

[ Edited on 3-1-2006 by humpty ]

Would you be interested in selling one of the chassis?

If so, how much?

Pete, & anyone else interested.
This is the wrong thread but ill add it to the buy & sell as well.
FYI.
I have a complete 1200cc Formula Vee here for sale on a registered open trailer.
The car is a !982 Trowbridge. These things were built in Tasmania by John Trowbridge and are a very close copy of an Elfin NG.
They are built very light and to this day, are still a successful budget vee package.

This one still wears its original aluminium bodywork which is so hideous to look at it actually attractive!
The car is cams logbooked.
It has all new hydraulics and only requires a controlled inlet manifold and a new safety harness to comply with Cams category 1 race cars.
Comes with excellent condition bridgestone tyres and a further spare set in VGC.

It is a get-in, turnkey proposition with a new battery.

The trailer is registered, recently painted with excellent radial tyres.

A bargain at $3000. as is, where is.
I can arrange freight to Melbourne or Sydney via TT-line ferries.
If any of you are interested, I can send some pix of the car & trailer.

L8tr
e

Tas,
only want the frame, a whole Vee would be wasted on me. Besides I already got a motor and box and the suspension is gonna need special work so cutting a perfectly good competition car is a waste of money.

Pete
It was a mighty long shot at best!!
However, finding bare cars/chassis is nigh on impossible.
You usually get most of the setup.
Keep ferreting!
L8tr M8
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