Road holding and handling........

[rgh0]

Mark

If you look at the Elanmods Yahoo web site you will see a post I did a while ago decribing the suspension setup on my Elan. This has taken me a lot of years to arrive at ( I take these things slowly) but it gives good control on the track and works for me.

Rohan

[M100]

I can adjust camber via adjustable spring perches

? ? ? ? ? ? ?

[type26owner]

Steve and Mark,
My car had the Dave Bean Stage 2 springs installed and shoed with Michellin 80 series tires with tissue thin sidewalls with 35psi the first time I ventured out onto the racetrack. Scared myself to the point I would have sold car if the handling could not be improved dramatically. Found with 55psi in the tires the car was drivable but very slow because it understeered.

BTW, If you do nothing but replace the donuts with CV halfshafts then the weight tranfer will exert even more weight onto the outside front tire sooner and it will understeer even worse. This is because the donuts kinda act like a swaybar but it's not enough.

The trick to getting a neutral handling car which is fast is to install a heavier front swaybar, stiffer springs, update the rear suspension as per Rohan's instructions (easy to do and the results are outstanding) and shoe it with stiffer sidewall tires. This keeps the bulk of weight transfer off the front tire so the rear tire shares the load otherwise it would be impossible to do a snap turn-in. How quickly the car will change directions and still remain neutral is the true measure of a good handling car IMHO. When it's right you can flick the car around and it will do a stable 4 wheel drift when the traction is exceeded without doing anything else nasty.

I'm running Bridgestone RE92 All-Season Radials with reinforced sidewalls and I'm not all that much slower than the guys with sticky race rubber. They can slowly walk away from me on the racetrack but not run.

[mark030358]

Rohan,
Do you have the web address? looked in yahoo groups with no joy

cheers
mark

[rgh0]

The article I wrote is below

The web site address is

http://autos.groups.yahoo.com/group/elanmods/




--- In [email protected], "pinsx3" <psteilberg@m...> wrote:
> what do you guys run for the following suspension specs for racing

Pete
My Elan is setup as follows for historic racing in Asutralia.

Front Toe in 6mm --I find I need this for high speed braking
stability especially on bumpy tracks.
Rear Toe in 2mm --The chassis and rear suspension arms are standard
and have not been adjusted they are the way it came.

These are measured as total toe in and are calculated as half the
track difference between the front and rear of the wheel at the rim
diameter.

Front camber neg 1 degree.
Rear camber neg 1.5 degree.

These are the result of slightly lower suspension height settings
than standard. The suspension arms and pivot locations are standard
just plastic bushes to replace the standard rubber one.

With driver on board
Front ride height at 110 mm
Rear ride height at 120 mm

These are measured with Yokohama A032R 175 x 60 - 13 on 5.5 inch
wheels with 260mm rolling radius at the bottom of the body sill just
behind the front wheel and just in front of the rear wheel. The
suspension is approx 10mm rear and 20 mm front lower than standard
and the wheels 20mm smaller rolling radius than orginal thus the 30
to 40mm lower ride height.

Springs are
Front 150 lb/in
Rear 115 lb/in
Roll bar 22mm ( 7/8 inch)
I also space the rear bump rubber approx 30 mm closer to the top of
the shocker using a 15mm nylon spacer above and below the bump
rubber. This stiffens the rear as you roll into a corner and also
stops the top of the shock chewing up the bump rubber. I run CV
joints which removes a little bit of roll stiffness from the rear
suspension compared to the donuts.

Bump travel at the front is standard less the 20mm lower suspension
travel. Bump travel at rear until it first contacts the bump rubbers
is approx 40mm less than standard with the 30mm spaced down bump
rubbers and 10mm lower suspension setting. Droop travel at front is
set by shocker length ( I use TTR racing front shocks). Droop travel
at rear is limited by a flexible steel cable to approx the orginal
setting. The Cv's will allow lower droop than the donuts but they can
start to bind at the full droop they allowso you need to limit droop
a little.


I run around 28 psi in the yokos with about 1 psi more in rear than
front. Many years ago when I ran dunlop formula ford slicks I would
use 23 to 25 psi for them. Others seem to like lower tyre pressures
than I do.


The car handles neutrally with good ability to adjust under or over
steer via the throttle in corner.
I find a little instability on turn in and through high speed corners
but it is only really significant on left hand turns and not on
right. My car is RHD so I have always presumed it relates to the
unavoidable weight bias to the right hand side of the car.

Rohan

[type26owner]

Following Rohan's advice I added a 75mm high stiff bumpstops underneath the existing soft silicone spongy ones. That's what the outside rear wheel suspension rolls over onto when cornering at the limit. The inside rear wheel must be restrained in droop otherwise it will allow the inside front wheel to be lifted clear off of the road with it's stiffer swaybar. That looks cool but is not the fast setup! It works this way because the Chapman strut is a heavy unsprung weight and it has a significant amount of lever arm moment to take advantage of and improve the handling. It's like when you try to bend over at the waist to pick something up off the ground and have to do without sticking out your bum. The only way it can be done is to stand on one leg and swing out the other leg to counterbalance yourself. Restraining the inside strut's droop works like swinging out the other leg.

The only drawback to this setup is encountering bumps at the apex. Stay off the bumps with the outside wheels when it's keeled over. It's okay to climb over the curbs with the inside wheels though.

[elansprint71]

I run my Sprint at 18 psi front and 24 rear, 175x70x13 Firestone F630 on 5" Minilites, that car sticks like glue at way faster speeds than I care to drive it. The maximum safe pressure for these tyres is 44 psi, it says on the wall.

Keith suggested 60-65 psi, do that you will probably crash. Those pressures are totally inappropriate for road tyres, what is more, the legal tolerance in the UK for deviating too far from the manufacturers recommendation is very small (+ or - 5psi?). If you are involved in an RTA, for whatever reason, the traffic cops will as a matter of course check your pressures, penalty points will follow if you are out of spec.

If you can get over to the CLOG meeting on 4th December we'll have a look at your set-up.

Cheers,
Pete.

[types26/36]

I agree, I run Pirelli P4's (155/80 x 13) and if I raise the front pressure over 25psi then the car becomes a boneshaker, you feel every rut and cobbled surface through the steering, the shocks are new and are set to the softest setting and the suspension components are fine, this can't be doing the suspension/steering/chassis any good.
The tyres are also marked with a 44psi max pressure and as Pete says raiseing the pressure is not only illegal (in the U.K) I think it would be dangerous partically on a wet road.
Brian

[rgh0]

While Keiths 60 psi is an extreme case you need to set pressures carefully based on your use and on both use and tire design.

Wall stiffness is very variable with current radial brands and different wall stiffness results in different pressure required. Also rim width versus tyre wdith and tyre profile all affect the required pressure. To a lesser extent suspension mods in terms of camber, spring and damper rates also affect best pressure. How much heat and pressure build up you need to allow for also needs to be consiered particularly in track work.

All of the above means the right cold presure for you and your car could be anywhere between 20 and 40 psi for the common range of tyres available for an Elan. The original Lotus specified pressures are meaningless unless you happen to have some NOS cross plys that have been stored in a refrigerator for the last 40 years.

With a new tyre type I start at 30psi front and rear and then work up and down until I find the optimum. Once I find an optimum of say 25 psi front and rear I then start playing with front rear split and may end up with say 24 psi front and 26 psi rear. Finally for a particular track I monitor hot pressure and may end up with different cold pressures left to right to balance out hot pressures. Most tracks will heat one front side tyre than the other.

Rohan

[steveww]

I found running the front lower than standard improves turn in and kills some of the understeer. Rohan settings confirm my findings which is good.

Having spent a lot of time on the track I have to say that tyre choice is the biggest factor in grip and handling (as long as there is not something totally wrong with the suspension). Yet it never ceases to surprise me that people will spend considerable money on springs, dampers, bushes etc then stick the cheapest tyres they can get their hands on. Those four palm sized contact patches are all that keeps you on the road. I have fitted Michelin XAS FF 155x13 tyres to my S4 and these are way better than the Dunlop SP10 that I took off. They are not cheap though. I still get some understeer but it only has the standard front anti-roll (sway) bar fitted. Might fit a thicker one this winter while I am rebuilding the rear suspension.

[sotul86]

I don?t know if this questions is relevant here but what differential do you guys have, i+m got 1:3,77 in mine but maybe want to go 1:3,9 ... but also changing to Yokahamas will change top speed to much ?

Mostly on small roads but sometimes on track....



Btw I have Front 200lb/in and back 130lb/in

[rgh0]

Johan

Selection of diff ratio needs to be matched to engine rev limit and power. tyre rolling radius and the tracks / roads you use the car on.

I use a 3.77 diff with the Yoko 165/60 x 13 that have a 260 mm rolling radius. That equates to 215 kmh in top at my 8300 rpm engine cut out setting. I hit this speed about two thirds of the way down the Phillip Island main straight which is the longest straight I race on. This setup also works OK for the shorter slower tracks and hill climbs I also compete on and given the pain in changing an Elan diff I wanted to find a setup that woked well every where and did not require diff ratio changes for different circuits.

Rohan

[type26owner]

The RE92 is not a 'shoddy tire'. It happens to have a speed rating of H and is robust enough to be used in a dual purpose manner. It can be taken up to the maximum speed capable of the Elan on the racetrack and still not blowout from going through potholes which I have to dodge around frequently on the public roads. It's also well suited to compliment the suspension modifications of the Dave Bean Stage 2 setup on 4.5" wheels.

Anyone that installs a race tire on the stock suspension and takes that up to speed is nuts. The stock setup was intensionally designed to appease the ladies so they would buy the car too. The springs are soft to give a smooth ride. The castor was reduced later on to make the steering wheel easier to turn. The power assisted brakes were added too. The stock configured car is too dangerous to do real performance type driving at high speed. If you think your car is going to handle well with the stock setup then you are sadly deluded. If you need help in the USA and don't trust me or Rohan then give Dave Bean a call and have a chat. Lee Chapman is also knowledgeable about the Elan.

Mark originally asked for advice to get his car to handle which he got some good and bad advice. May I suggest you first tune yourself up. Attending a performance driving school is the best way for you learn how this stuff works in a safe controlled way. Doing performance driving out on the public roads is wrong. Take it to the racetrack instead.

[mark030358]

Pete,
Will try to get to your meeting on the 4th provided theweather is fair!
Do you have a post code for the meet, so I can to a route plan.

cheers
Mark

[jkolb]

Rohan and Keith

What length cable do you use for the droop stop and where do you attach it?

Jerry