Friday, 22 May 2015

Flat Flooring by Rat Race Motorsport

After experiencing some pretty significant understeer on various track days (the most recent being Folembray a couple of weeks ago), I've since been researching a number of ways to cure the problem (see this first corner, and the same corner at 58 seconds into the video below):-

From a different driving style, to anti roll bar settings, shock valves, flat flooring, the list is endless... A bit of head scratching, some questions asked on the lotus seven club and to some other suspension 'gurus' I decided to have the geometry and suspension setup adjusted which is known as having the car 'flat floored'.

Whilst building my car last year, a local Caterham owner told me about Rat Race Motorsport, suggested Rob there was a decent guy, and I should give them a call if I was interested in getting my car flat floored or even having any service work done and so on.  I'd kept this in mind, and tried over the last couple of weeks to contact them, but there was never any answer on their landline... The long and short of this is that Rob is usually under cars - and subsequently can't get to the landline in time to answer it, so he prefers if you call him on his mobile 07956 269605.
After agreeing a price and time, I took my car down to his workshop in Potters Bar.  We discussed what I was struggling with, what my weight is and how I'd like the car to handle in an ideal world.  Rob's answer was pretty much 'Yes I know exactly what to do' which was good to hear... So I left the car with him for the day to do his magic.

Rob put the car on the scales and made a note of the existing settings.
Caterham R500 going onto the weigh bridge
Caterham R500 going onto the weigh bridge
The scales actually gave some interesting results... The weight for a start is somewhat heavier than the quoted 506kg, and they also suggested the settings were far from ideal.  More about this on this page of my blog.

Geometry adjustments
Rob commented that the A-frame, De-dion and caster settings were very good, and testament to a well built car - which was either fact or flattery - either way I'm happy with that!

He went on to say that the ride height wasn't ideal though, raised the front by around 8-10mm and the rear was lowered by 6mm which left the car with a rake of around fifteen degrees.  Rob winds the shocks in full then dials them out giving a positive number, whereas Nitron do it the other way around - anyway the front shock damping setting was changed to +8 (-16 in Nitron terms) and the rears to +12 (-12 in Nitron terms).

The front toe was changed as adjusting the ride height would effect this, so the car has been set back to a fairly neutral setting with a little toe-in.  The front camber was also changed for similar reasons, but is running 2 degrees negative.

The rear toe remained unchanged as this was spot on.

Corner weighting
The final job was to adjust the weight on each corner for a perfect balance... 83 kilos of weight was added (which is my weight plus crash helmet) and then the preload platforms were wound across the front, then diagonally against the rears until the perfect weight distribution setting was achieved. 
Caterham R500 on weigh bridge
Caterham R500 on weigh bridge
On the journey home I decided to take a 'detour' (as you do in  Caterham!) and go for an extended blat to see if I could notice any differences... To be fair the main understeer problem was on medium to high speed corners on tracks, which is difficult (if not impossible) to replicate on road driving, but the car did turn noticeably more with additional steering angle, which will hopefully be replicated on circuits.

I guess the full and final test will be at Cadwell Park this coming Monday (25th May 2015) where I'll be on a track day, which I'm very much looking forward to.

Overall a good service and from my initial findings a job well done by Rob at Rat Race Motorsport.  A link to their website can be found below, along with his mobile number - 07956 269605.

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