Banks S2 Race Car

[JR73]

Thank you BDA.

As requested (best you ask as I'm bound to miss/forget the intricacies!)
Wheels are Richards 3 piece split rims, made as a replica of the 4 spokes fitted to the 47's. The manufacturer of these is Image Wheels and you can buy a VERY similar wheel directly from them now but they have repositioned the wheel nuts (probably because Richard owns the rights to his version or something?).
Fronts are 15" x 7.5"
Rears are 15" x 8"
The slicks I raced on where Avons - the softest compound available for slicks in the correct sizes was really meant for much heavier Touring Cars so it took a good few laps to get them up to temperature but the advantage of this was that they lasted a fair few events (!) and I tended to be able to take advantage of the improved performance from them in the second half of a race as most people where starting to ease up or even cook their tyres on a hot day...
The fronts where 7.5/21.5-15 and the rears 8.0/21.5-15. The 21.5" is what Richards suspension geometry was designed for - trying to find road tyres to fit those wheels with the same overall size was a real chore - especially as I wanted something at least a little performance orientated. Avon had exactly the correct size (basically a cut slick road legal tyre! - ACB10sport) but I didn't want to stump up the quite extortionate price for these until I had actually got the car on the road to see if it was going to be enjoyable/useable!
I have Toyo r888's on the Caterham and being able to purchase different compounds would make them my first choice for the Europa BUT the sizes aren't quite correct which would have caused issues with clearance, the next best thing in my opinion was their T1r so I currently have 195/45/r15 on the front and 205/45/r15 on the rear. I haven't had chance to investigate the ideal tyre pressure to run these at on the road just yet but Toyo recommend an operating pressure of around 26psi.

Raced on various spring rates, up to 450lb on the front and generally stuck with 250lb on the rear. Also had a selection of adjustable high level front anti roll bars (based on Richards design but of different diameters etc) to select from. Richard used to discourage anyone from fitting a rear anti roll bar (I never fitted one) and I don't know if he still does but I did fit them to a couple of cars and saw a measurable improvement from having one fitted on track at least.
For the road I have opted for 250lb front and rear, 250lb fronts is what we used to fit to the Banks chassis cars that where for fast road/track day use with around 180lb on the rears.
From the initial road miles I have done this weekend I'm quite happy with 250lb front and rear so far....

Shocks fitted are Richards race spec Avo adjustables - relatively cheap in the world of race spec shock absorbers but they have been pounded around many race tracks over the years and I can say that they have survived really quite well! The single way adjusters give a noticeable difference across the range of adjustment (in a wet race I used to disconnect the anti roll bar and go full soft on the dampers front and rear which made things supple enough to gain some grip in the conditions) this was altered to suit conditions and tracks along with the spring rates.
For the road I have settled on 8 clicks from soft on the front (14 clicks total) and 3 from soft on the rear. This gives me quite a firm ride but feels compliant enough over bumps etc. - my personal preference tbh.

I can't remember the full alignment figures off the top of my head (can't find my setup book either atm!) but I know the front has 0 toe and I'm pretty sure I run the same on the rear. Camber/castor escapes me atm but I run negative camber at both ends but differing amounts...
Worth mentioning here that I have Richards tubular chassis with the double wishbone rear suspension, this is fitted with his race spec bushes all around and these give zero movement fore and aft but are very free moving in the vertical - you don't have to sit the car at ride height to tighten any of the suspension bolts for example.
The other benefit of this chassis is that you can dial out any bump steer at the front by careful shimming of the rack at its mountings. Also the rear geometry has no bump steer and minimal camber change through its full range of movement - the top wishbone mounts are further inboard than the Spyder versions for example which allows the top and bottom wishbones to stay parallel as they move. - I don't think many people really appreciate the amount of engineering that went into Richards chassis, yes it basically replaces an original and fits in the same space but there are so many areas that have been subtley redesigned for the better that I think even Richard himself has forgotten about half of them!

As for further modifications - probably best to say that the original body shell was used (much lighter than the modern replacements can get close to!) but with a fibreglass bulkhead bonded in place and the front indicator mounts flushed across the top but left open to give a small amount of extra air into the front plenum as the radiator now vents out through the front bonnet and the mounting for the radiator forms a duct that only allows the air that passes through the front grill to go through the radiator. Other than the above mods the body is the most standard part of the car! Everything else is different from original or modified at least... the majority is available from Banks as far as I know?

Quick spec of other parts;
Vented front discs with Banks spec calipers
Solid rear discs with Banks spec calipers
Banks balance bar adjustable pedal box with twin master cylinders - 0.7's from memory as I'm not currently near the car and no servo assist
Banks tubular front wishbones with camber adjustable top wishbones
Quick release steering wheel, race seats that allow the driver to be positioned closer to the centre tunnel which also improves the ergonomics relating to wheel/pedal/seat alignment. 4 point Willans 3" lap and shoulder race harnesses.
Banks multipoint bolt in roll cage
Polycarbonate fixed side windows mounted in lightweight S1 style doors and poly rear window with vent holes(if not for the weight saving its SOOO much easier to fit than the glass original!!)
5 speed gearbox with Banks gear linkage - the linkage kit properly set up is like a rifle bolt in precision and well worth the money!

As for the engine... originally fitted to a Vauxhall Nova Gte/GSI it's a 1600cc, 8 valve. All tuning parts purchased from Enem.
Crank, Rods, Pistons, Flywheel - lightened, balanced, ARP bolts throughout, higher compression.
Cylinder head - large valves, solid lifters, full race cam, flowed to suit, Twin Weber dcoe 45's with intake manifold to suit - this is a work of art to look down as it is blended/flowed to match the intake ports to perfection!
Tony Law race exhaust system with repackable silencer.
Engine revs to 9000rpm and produces 175bhp at the wheels. (Did once rev it to 9500rpm in the heat of battle but broke a follower - still managed to finish)
In race spec the car weighed 640kgs with fluids (class limit!) and in road spec now weighs 650kgs

Can't think of anything else but there is probably all sorts that I've forgotten

Not really sure where to begin with recounting my time working for Richard? By all means, ask about anything you may wish to know...?

Jon

[BDA]

Whew! Thanks Jon! That's a lot more than I expected! That was a lot of great information. You certainly had a well thought out and sorted car. I have no trouble believing that Richard's tube frame is very nicely done but unfortunately, I didn't know about Richard when I got my frame (I have a Spyder frame before they went to their tube frame).

I was interested, and I figured others would also have an academic interest in your setup for your race car but I was mostly interested in your street setup, especially since Richard advised me when I built my car.

I have Richard's adjustable front upper A-arms and stock lower A-arms. I also have an early version of Richard's twin link rear suspension (it has a much larger cross member). Richard suggested 250# springs in the front and 130# in the rear. I have SPAX shocks that I got before I hooked up with Richard. I run 195/50-15 tires in the front and 205/15-15 in the rear. I also have Richard's vented front discs and solid rear discs. So in some ways, our cars are a somewhat similar.

Question: What did you do for rear stub axles? Did you live with the stock axles or did you go with Richard's hardened shafts?

But I was mainly concerned about my spring/shock setup. I had been experiencing a "nervousness" in the car at high speed. I felt that even slight steering inputs would cause much greater changes in direction than I wanted so it required a lot of attention. I've been working on my alignment (it turns out that I had more caster on the left than the left, which I've fixed now) and I am going to have my rear toe reduced mostly for tire wear. I recently learned a little bit about how shocks impact handling so I've started stiffening up my shocks but wondered if they might become too stiff before they helped with stability but from what you're reporting, I probably shouldn't worry so much about that.

Your comments about a rear roll bar are interesting. My car feels more inclined to oversteer so a rear bar doesn't seem to make sense but then there's what you saw...

I'm sure I'll think of some more questions given time...

Thanks for your taking the time to give all those details! She sounds like a great car with a wrench and driver to match!

[JR73]

I did go on a bit there....!

The rear uprights are Richards own fabricated ones that where designed to go with his double wishbone setup, as a result the bearing carriers, brakes and driveshafts are all of Ford Sierra origin (I'm sure this is no secret as exactly the same components where used on Caterham's for many years) with the shaft length either modified to suit from some standard Sierra sourced parts (cutting the shaft and turning a peg and dowel on each half, fitting together and then welding around the joint) or having some fabricated to suit. - mine are original spec cut n shuts!
The inboard and outboard joints are as per the Ford, bolting to either flange (you can remove them without dismantling the outer hub and by leaving the gearbox output flange in place) and Richard has the gearbox output flanges manufactured to fit straight on the Renault transaxle.

As I've mentioned elsewhere, I retired the Europa from racing (for fear of it getting smashed up! - far too attached to it to see that happen!) and built a big Europa in the form of an Esprit V8.

With the frame setup you have mentioned fitted with the twin link rear the Esprit is basically the same design as what you have (can't argue with Lotus suspension design being pretty good can we?!) - the stock road car drives great and I have done a few road miles in different Esprits including the V8's to say that I've never had any handling issues to be concerned about.

However, my racer with sticky slicks and an increased power output was initially somewhat different.... again, all the suspension bushes where changed from the original spec to either solid or rose jointed - rear links are now all rose jointed as the geometry on the rear of an Esprit requires some 'twist' in each joint as the suspension is raised/lowered due to it tracing an arc from the trailing arm front pivot point.

When it was first built though I discovered that when fitted with polybushes in the rear upper and lower links the suspension locked out at either end of its range - this then transferred forces into the trailing arm pivot (big rubber bush just like on a Europa) which caused it to deform and the toe alters as it does so. The rear wheels where basically steering due to the trailing arm pivot being pulled and pushed due to a combination of much stickier tyres, increased horsepower and stiffer bushes. Apart from going to rose joints on the upper and lower links the answer was to also replace the trailing arm pivot with what is effectively a large rose joint that mounts to the frame in the same way as the stock one which doesn't allow any deformation - all the works prepared Esprit race cars I've seen have this very setup and it definitely made a difference to the handling on mine.

It may be worth investigating on yours - remove the rear spring and move the suspension through its range from full droop to full compression and pay close attention to the front pivot to see if there is any change in the rear toe? I've never checked that on a Europa fitted with a twin link rear so I could be barking up the wrong tree so to speak...


The rear anti roll bar would just allow for further fine tuning of the rear suspension relative to the front... it does what it describes, controls the body roll which means that you aren't relying on the spring and damper setup to resist the roll (can end up with stiff springs and hard damper settings to try to prevent body roll - the bar would be taking care of that which would allow for softer springs and damper settings for example) - I haven't fitted one to my car as I always found it quite neutral handling which allowed for under and over steer at the limit depending on throttle and steering inputs.

Are you actually experiencing oversteer or do you get the sensation of it oversteering when cornering?
Apart from checking the rear links and pivot for movement it could be caused by tyre pressures, ride heights front to rear, damper settings..... I've read that you used to race so I'm sure you know how to adjust these things out but remember that any change you make at the front is relative to the rear and vice versa - if the rear feels loose it could be that the front is too soft relative to it...if you get what I mean?!

Another war and peace.....sorry!

[BDA]

Thanks again for your very detailed reply and the mini vehicle dynamics lesson! As you Brits say, every day is a school day!

I did race many years ago but the funny (or stupid) thing is that I am learning more about vehicle dynamics now than then. Looking back, I wish I had experimented more back then but most of my races were seven or more hours away. There might have been track days then but if there were, the closest would have been at Road Atlanta over ten hours away. I pretty much aligned my Lola as they told me to (it had non adjustable shocks) and it seemed to handle really well so I didn't mess with it too much. Oh, I was also going to school during this time so my time and resources were pretty limited. All that being said, it was a lost opportunity to learn more that I regret. Now that I'm a "pensioner" I have more time monkey with my car (which may not necessarily be a good thing!) but my car is my hobby now.

I should say that my purpose isn't to have a track car but probably closer to an autocross car - even though I don't intend to autocross it. Just something that handles well so it's more fun to drive faster than I'm supposed to.

Anyway, now I'm concerned with the handling of my Europa so I'm trying to learn more. I'm about to convert the rubber bushed rod ends to spherical rod ends - mainly to make it easier to assemble. After that, other than the inboard upper link, all the links will use rod ends. My trailing arm pivot is the stock rubber bush. In the front, I'm using the stock bushes and I still use the stock anti roll bar - no bar in the rear. Richard suggested front pressures between 15 and 18 psi. and rear between 26 and 26. So that's a more complete picture of my car suspension wise.

No I don't actually get oversteer but going into turn it feels like it wants to swap ends. After alignment, which will I will get more serious about after I get my rod ends installed, adjusting my shocks is were I plan to experiment next. At the moment, I've stiffened them three clicks all around (these are pretty old and there may only be 14 clicks total) and it seems to be a bit more stable but I haven't tried it on the highway yet to be sure. I'll probably try stiffening the front shocks more next. Somebody suggested

Any advice would be greatly appreciated!

[gideon]

Jon, the detail is great. Keep writing.

[Bainford]

Congrats. Your Europa is gorgeous and makes a fine road car. That's a very interesting treatment for the front signal lights. An neat mod for those who don't like the signal light warts.

Are those interior door latch pulls on the upper surface of the doors (at the base of the window)? Another very interesting mod. Was there a specific reason for putting the latch release there?

[jbcollier]

BDA, I set mine up with minimal rear toe and it felt just like yours.  I added a bit more rear toe and it felt much better,  I plan to add yet more soon.

[JR73]

Bainford, yes they are the interior door latch pulls mounted on the upper surface of the door - there is a slot in the side window to get your fingers through to lift the flap so that you can use the one pull to open from the inside and the outside - a nod towards weight saving and a way of reusing some of the original parts.

The indicator light 'warts' where removed when I had no intention of using it on the road so everything was done with the track in mind - that was just a way of retaining a nod to what was there but using it as a vent for air into the plenum area.... I have simply used some small motorcycle indicators that fit inside what was left as I didn't want to return the original 'warts'!

BDA, good to hear that you are already heading down the trail of fitting rod ends to the upper and lower links - it should compare quite closely with what I found was happening on the Esprit tbh.
The reason I asked if you had actual oversteer or the sensation of it was because I too found that there was no actual slip occurring but the sensation was there which was quite unnerving at high speed - as the outer rear wheel was loaded up through the corner the area that allowed the most movement was the trailing arm pivot bush, this was made worse still when the upper and lower link bushes effectively locked out as it put even more force on the pivot bush which pulled it through the chassis a small amount and toed the rear wheel out more than it was set too - gives the sensation of oversteer as the inner rear wheel doesn't have the same loading and is likely set with toe in which then means that you are kinda 4 wheel steering (end up tracing a tighter radius around the corner than you intended....) you may need more toe in on the rear to prevent the outer rear from being forced into a 'toe out' value when heavily loaded?

I would have gone the opposite way with tyre pressures than what Richard has suggested - mainly because the weight is biased towards the rear tyres slightly and the power is transmitted through them so they get worked more than the fronts so you should get more heat into them quicker which increases the pressures - ultimately you are trying to get all four to the same operating pressure... also the soft fronts will give you increased turn in and the harder rears in relation to this will give you less lateral grip which can promote oversteer. Look at Drift cars - they run soft front ends to promote turn in with hard rear ends (suspension and tyres) to help break traction....

I have 14 clicks of adjustment too, if they are working as they should then you will have more than enough to play with and make a difference.
Try a harder front softer rear setup - promoting the rear to get a better grip of the surface and the front less so (relative to one another).

Ultimately it can come down to personal preference, driving style can play a factor in it too - pitching hard and late in towards an apex can promote the rear to break traction compared to a smooth and flowing turn in - bank robbers in the movies could get away from the cops much quicker if they spent less time sideways and sawing at the wheel....! Ha ha. (You know what I mean though?!)

[BDA]

JB, I look forward to hearing more about your rear toe experiments since our rear suspensions are pretty similar. What toe in are you running now?

I originally had my rear toe set on a rack to be in the middle of the stated spec - 3/16". I have a note in my notebook that I measured it at 35' which converts to .23" so there is some confusion there but I'm sure that I had a decent amount of toe. My rear tires wore out in about 8000 miles so I'm going to have it set with less toe in and see how that goes.

I was interested in Jon's comments that he ran with essentially zero to in front and rear and said it felt good to him.

Jon, since I have owned my car since new, I have a memory of how it used to handle on the highway and back then. I had 90 mph for hours on end with little effort. More recently, I've driven 90 mph and it required quite a bit of concentration. Also, I don't remember that sensation that the rear would come around so I need to do some more tuning to address the changes I've made!

WRT rear toe in in hard turns, I doubt seriously I have or will stress my trailing arm bush nearly as much as you have and like I say, the feeling that it was trying to swap ends in a turn wasn't something I remember feeling when the car was stock so I'm looking more at shocks and alignment - and now tire pressures as potential fixes. I have considered ball joint trailing arm pivots but they are on a list of potential upgrades that seems to grow the more I do to my car!

[JR73]

The alignment settings on my Europa where arrived at from being able to see what was working on all the other cars I was involved in setting up at the time (at Banks) along with getting to know a couple of guys that had been racing for many many years - one of which was running a near identical car to mine and as I was building my car I was crewing for him at the track and helping to decide on setups etc (we must have got something right because he won the championship! - good driving being the major aspect though!!).
The spring rates that he and I used, along with the anti roll bars that we fitted were somewhat against Richards advice at the time tbh (we figured that they where our cars so we would try whatever we thought would work!) and after him winning the championship there wasn't much to suggest that we were wrong....!
Lots of factors played a part in the decisions, there is a way of reading the grain on slick tyres - you can see what effects the toe, camber, tyre pressures, damper settings etc are having by looking at how the tyre is wearing, changing colour, graining up etc.
Being able to watch the attitude of the car as it's cornering can be useful (maybe get somone to film you around a selection of corners that you can revisit after making some adjustments?)
Obviously driver feedback is important too - doesn't matter how correctly you think something is set up on paper, if the driver isn't comfortable with it then they won't enjoy driving it - we had similar driving styles and VERY similar cars so it was easier for us to compare notes on all of the above so to speak.

BDA - I wouldn't suggest that you should run zero toe all around tbh, it would probably be fine on the front but with the trailing arms setup I would expect you to need some toe in. (Even with rose joints on every suspension point on the rear of my Esprit i still run some toe in on it. - the wheel doesn't have a 'clean up and down movement' so to speak.) before I changed the trailing arm pivot I could see movement in the pivot bush by removing the rear springs, putting a jack under the rear chassis hoop and with a set of tracking gauges on the rear wheels I could see the toe alter as I jacked the rear up and down. - an easy enough test for you to try? Hopefully you won't have any movement but at least you will know.
Having the same sized tyres as me I'm pretty sure that makes them wider than original? - I doubt the workshop manual settings would be optimal for those either. I'd be interested to hear about your findings and suggest that you don't change too much at once, it may take a little time but it's best to change one thing at a time and record the difference in the form of a set up chart to refer back to.

Bainford, cropped close up of the slot in the window to operate the door latch

[BDA]

The little fooling around I've done, I've noticed that the camber and toe change a lot with the ride height. I think your test in a valuable exercise. After I get the upper link rod ends in and aligned, I'll do it and see what happens. In any case, I agree that toe in is needed for stability on the highway. My idea is to use as little toe in as I feel comfortable with so I can get a bit better tire wear. (It seems that mid engine cars wear their rear tires out pretty quickly. I don't know why it would be any worse than a front wheel drive car!)

As for camber, someone posted somewhere that his idea was to go the minimum negative camber since the tires are more "square" than the tires in the '70s. My last set of rear tires wore evenly but quickly. Unfortunately, I didn't take good notes on the alignment I was using with them. I'm running -30' at the moment. Taking your point that the stock alignment specs may not be appropriate for our tires, it might be worth experimenting outside the stock specs but the manual states rear camber should be between -30' to -1° 30'. I wouldn't think experimenting with more negative camber but maybe less than -30'.

I'll start seriously investigating after I get my rod ends installed and a starting alignment done. I'll post what I find out.

[Bainford]

Bainford, cropped close up of the slot in the window to operate the door latch

Thanks for that. A very interesting mod.

And thanks too, for the detailed set up and chassis info you have been regaling us with. I'm digging the discussion. School is in!