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equal diagnal or equal on the front (set up)


david nelson

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Equal diagonal means they soften the right rear shock to achieve the diagonal balance, totaly different from the usual method we see on tech talk and i have to say it makes sense

Just had along conversation with Troy at Northampton Motorsport after they set my car up yesterday. He is convinced it is the way to go with a Caterham. Felt great on the way back too

He sets one of the regular Caterham racers up and they are a regular on the podium

Transformed the Linds machine last week too

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Equal fronts will give you equal retardation on the front (assuming a flat surface) so you should not lock one front under braking. However, cornering grip is slightly uneven on left and right turns because one side has more weight/lateral grip than the other.

 

Equal diagonals should give equal cornering grip but one front will lock before the other under braking.

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I've done my own car setups for a good couple of years now which have served me pretty well *wink*

 

I've alway gone for the equal(ish) front's route. I don't worry to the last kg as long as the offside one the heavier of the two. I'm happy to be up to 10kg heavier that side as most circuits are clockwise hence more right turns to trail brake into.

 

I wouldn't try following Mr Hatters advise to soften off the right rear shock any time soon though if I were you I'm guessing he means reduce the pressure on that side's spring platform, thereby taking weight off that corner, but may be wrong *smile*

 

Just redone my Busa's setup, with my weight in the car & the fronts within 10kg of each other, the diagonal weights were 50.2% & 49.8% anyhow *thumbup*

 

Edited by - DSL on 27 Apr 2011 20:36:44

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What do you mean steady 🤔

 

I'm at a loss as to why you would be advised that softening off one rear damper would affect the static corner weights *confused* Perhaps you could explain the theory of this to us, maybe that's a trick we are all missing *confused*

 

Surely the spring when static would push the damper back to its normal ride height, on more or less on any setting unless massively stiff & as such not effect the corner weights 🤔 My understanding is that dampers only control the transient weight shift so I can't see what your suggesting being correct *confused*

 

Doing as you suggest would affect the time taken to load / unload that spring when on the move, effectively giving a temporary differential in wheel weights from what I gather but saying that I have never heard of anyone suggesting that you run unequal damper settings on opposing sides of the same axle 🤔

 

 

 

 

 

 

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Darren - I don't think Carl has read your first response fully.

 

He has not understood as most of the race cars that teams set up have non adjustable Bilies and its therefore impossible to "soften off" one damper. Adjusting its load as you state is certainly possible - although I do not go for that.

 

I'm with you on the equal fronts. I understand the diagonal theory but I would rather have maximum breaking available in a balanced car.

 

Must say I am surprised at the diagonal percentage (is that with you in the car?)

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How does weight transfer under braking affect the front corner weights? Does more weight on the right of the car (driver) lead to more weight transferred to the front right? I can't quite get my head around it, does anyone know?

 

If it does work that way then there could be some science behind the diagonal method?

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Here you go Simon, unfortunately working from memory typing that last night it would appear I was 0.1 % out *wink*

 

F/ NS - 120KG

R/ OS- 159.5KG

 

= 50.3 %

 

F/ OS- 128.5KG

R/ NS- 147.5KG

 

= 49.7 %

 

555.5KG total with my 92kg in & 10 ltrs of fuel, but no bonnet or nose cone on.

 

With a Busa install the engine is right over towards the nearside chassis rail along with the dry sump tank with its 7 ltrs off oil right in front of the passenger footwell *thumbup*

 

 

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in theory - diagonals better around corners , equal fronts better under braking

 

but the road is never flat and the car is leaning round corners and the weight skew on a conventional engine 7 is over the drivers rear corner which makes the front weights very unequal when chasing equal diagonals , it's all a compromise without actually moving weight around ....

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No one's getting into a slanging match, I just want to ensure that the correct interpretation of the supplied information has been posted here *confused* I doubt that Northhampton motorsport are actually advocating running one rear shock much softer than the other to affect corner weights, I still think they mean that the platform height on one side has been changed taking compression off that spring which will affect corner weights *smile*

 

It has been pointed out by several smart people, inc an ex- F1 guy, that maybe you should not set up a Caterham using the diagonal method as it has a fixed beam across the back, i.e. the De-dion tube. They advocate equal front's, with the rears as close as poss, but hey go with whatever suits you *wink*

 

 

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*arrowup*Nail on the head Darren

Sorry thats what i was trying to say

I did question Troy over it and he is confident its the way to go and i am all for trying a different option

Most of the Westfields are set up this way apparantly, surely there cant be that much difference in chassis set up between the 2 🤔

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That's better, makes sense now *wavey*

 

It's is a personal choice to either go for equal fronts or diagonals in a 7, can't say I've ever tried it myself, maybe its great for circuit use *confused* However for sprints / hills the braking tends to be more important.

 

Its a lot easier with a single seater car such as the Radical PR6 with one centrally mounted seat as there's very little in it, saying that I still went for equal fronts with the offside one a tad heavier.

 

The Autosport Golden helmet sat on my cabinet suggests I can't be too far wrong *smokin*

 

Edited by - DSL on 28 Apr 2011 11:37:27

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Troy asked me to post his reply on this thread

 

Just to clarify matters regarding the right rear damper we have lowered the spring platform to reduce the static weight on that corner rather than adjusting the damping settings.

 

We have always set Caterhams and Westfield's up to have as close to a 50% cross weight as possible regardless of whether they are live axle, De Dion or independent. The feedback I get from our customers is that the cars are nicely balanced and predictable through right and left hander's and are balanced on the the brakes. I agree that a 50 % cross weight can in some cases lead to the left front wheel locking but in my personal experience of racing our Westfield the weight shift forward under braking almost completely overcomes the slight weight imbalance. In fact I would say being able to pass other cars under braking was one our cars strengths.

 

with CEC and an average 80 ish KG driver we usually see between 12 to 15 kg discrepancy across the front axle and 15 to 20 across the rear axle with a 50% cross weight. By carefully adjusting the platforms on the dampers the ride height is pretty good but the right rear corner will always be slightly lower than the left rear corner. BEC's are slightly better on the cross axle weight distribution as the gearbox and engine are effectively one unit and generally smaller and therefore offset to the left of the car slightly which helps with weight distribution.

 

With cars that have no real aero performance then I believe weight distribution is more important than ride height (within reason) however, on cars with significant aero such as some formula cars, Radicals and no doubt the SP/300 etc it is very important to respect the ride height to maintain the aero package efficiency.

 

At the end of the day the ideal set up is really dictated by tyre type, suspension design, and testing whilst keeping a detailed record of ambient conditions, tyre pressures, tyre temperature, damper and roll bar settings to allow you to home in on the ideal set up that utilises the tyre to its maximum. Throw into this driver preference and you can see how arriving at a definitive set up for all cars/drivers is difficult.

 

Most important is to have a car that inspires confidence under all conditions as this will allow the driver to extract the best from the car, braking later and getting on the throttle earlier and feeling like the car is actually responding to driver input. Most sevens will out handle your average sports car even when badly set up so until you get everything properly aligned you just don't realise how good it can be. The R400 we did today actually had positive camber on the o/s/f wheel.

 

I would be the last person to suggest that we know everything about setting up sevens but I reckon we can get 95 to 98% of the way there, the last bit only comes from testing and driver input.

 

 

hope that helps

 

Regards

Troy Robinson

 

Northampton Motorsport Ltd

 

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