Corner balance, alignment and suspension setup

[vstryker]

Well I finally had a chance to corner balance, align the 7, and fiddled with the suspension to my liking after Magnus generously lent me his scales and tools. It was fairly straight forward as I took my time, leveled the scales with a laser, R888 tires set at 17psi front & 19psi rear, and added 160lbs to the driver seat in rice bags with 1/2 tank of gas. Here are my initial readings:



I was hoping to hit the 1200lbs mark without me, but it hit 1240lbs with no driver. It is a SLR with tillet seats, no heater, no doors or any weather equipment, no spare tire or mount, FIA rollbar, 4lb battery, 2L Zetec SVT, 6 speed, CF wings and cone, and glass windscreen. Now where else can I remove weight?

I know the rear camber and toe aren't adjustable without the correct "ears" but does this look normal as the rear right toe is a bit off? With my other cars, on the rears I usually liked a little more negative camber (~2آ°) and about 1-1.5mm of toe in per side for stability.

I evened out the caster so I moved the shims on the left front to achieve a more even left-right. The rear bolt on the front lower control arm was PITA to get to. The right front camber was also adjusted, toe zeroed and after playing around with the ride heights, this was the result:



My final ride height came out to be about 135mm front, 150mm rear. I also moved the rear ARB from stiffest 4 to to 2nd softest at 2 as suggested by a few guys, set both rebound and high compression on a fairly soft street setting with low compression slightly firmer. After a few hours of driving around in the twisties, a few clicks firmer on the low compression and softer on high, I think I have a good baseline for the track/autox as now it feels very well balanced.

[Doug Liedblad]

Did you disconnect the sway bars when you had it on the scales?

How close did you get the scales to level? I use a water level which is closer than the laser but I don't know if the difference is of any significance.

Did you get the crack in the front tube fixed?

Other places to remove weight - ignition switch. It weights 2 lbs or more. I've also removed the windshield wiper motor having no need as I run Brooklands. It weighs several lbs.

The rear toe should be Zero both sides, check to see if the DeDion ears are bent or cracked. Or the tube itself.

My car is not a superlight, I have removed the spare tire and carrier, parking brake, carpet, jack and tool kit, items above and I am also about 1240 lbs with some fuel in it.

Doug

[vstryker]

Yes, I did disconnect the sway bars & yes the crack was repaired a few weeks ago. John West did an excellent job & didnt charge me either.

I managed to get the scales within +-2mm of each other which was good enough for me.

I'll think about removing the ignition & will remove the wiper motor once I find the correct plugs. I also have the Aero screen so I'll swap it out when on the track, saving me a few more pounds & maybe a lightweight fw too.

Oh Btw, i forgot to mention my spring rates: 300# front & 250# rear with smaller progressive spring set up by Meteor.

[Doug Liedblad]

Three hundred front and 250 rear is on the heavy side for street use. Even for the odd track day.

250 front and stock progressives on the rear is what I run.

But I also don't have your shocks.

[moosetestbestanden]

I was hoping to hit the 1200lbs mark without me, but it hit 1240lbs with no driver. It is a SLR with tillet seats, no heater, no doors or any weather equipment, no spare tire or mount, FIA rollbar, 4lb battery, 2L Zetec SVT, 6 speed, CF wings and cone, and glass windscreen. Now where else can I remove weight?

1. Remove the windscreen
2. Remove the Zetec & replace w/ a lighter engine.

Any change after that is incremental.

I know the rear camber and toe aren't adjustable without the correct "ears" but does this look normal as the rear right toe is a bit off? With my other cars, on the rears I usually liked a little more negative camber (~2آ°) and about 1-1.5mm of toe in per side for stability.

Rear camber as set by the ears is putatively for the difference between bias ply & radial tires. Back in the old days, there was a thread on BC about that. It seems there was a guy who won a championship running the "wrong" ears. I've used both ears w/ both kinds of tires. I'm not sure I've been able to tell much difference, but then that probably says as much about my skill, and/or other rear suspension factors as it does about rear camber & ears. ISTR that the difference isn't a lot.

[magnusfeuer]

If the right rear toe in bothers you, have a machinist fabricate a new one that compensates for it.

Do you know what the clearance between the sump and the ground is? Should be 65mm for track and 75mm for street.

Another reference point is to ensure that the lower A-Arms are horizontal when the car has its driver in it.

/Magnus F.

[super7guy]

It is my experience, to check for the steering arms to be close to horizontal, which puts the lower arms relative to chassis in droop and the upper arms in rise.

Wayne in San Diego

[Doug Liedblad]

If the right rear toe in bothers you, have a machinist fabricate a new one that compensates for it.

/Magnus F.

He should really check for something bent first. The older ears are castings and can crack or DeDion could be bent.

Doug

[magnusfeuer]

I agree with Doug.

The rear wheel angles are all determined by the DeDion tube. The pre 2002 tubes were too weak in their shock absorber mounts, which could break loose. This should not be an issue for Van, though, since his car is much newer. Check the tube and ears for damage.

/Magnus F.

[Doug Liedblad]

The DeDion tube failures were dependent on the way it was built. Mine was done September of 2001 and has no issues. It has the welds in the correct place. Others from that era did have issues. As Magnus says Van's should be OK. My concern is if it was bent by pothole or when the front hit the rock. Perhaps the rear did as well. Same side I believe.

Just have a closer look to be sure. We looked at it and saw nothing at the time but that was before he did the alignment which now indicates he should take a closer look.

[vstryker]

I just ran out to check, the lowest part of the oil pan is actually 75 mm to my surprise.

Checked the front lower arms & both are dead horizontally parallel with the ground.

Last time I took my Dedion apart I did not see anything bent or out of the ordinary & noticed the ears looked fairly new. It was a solid piece aluminum, not cast. But ill double check again this weekend & see. The +1.5mm is actually Toe Out on the rear right... But it could easily be my slightly inaccurate method of measuring. I'll verify it @ the Alignment shop.

On a side note, I fixed the small play in the shifter. I opened it to find the plastic saddle broken in 3 places, replaced it with a new one & voila, feels perfect now, absolutely no play.

Also removed 5lbs taking out the wiper motor... Now to find the correct sized plugs. I love working on this car, it is so freaking easy.

[magnusfeuer]

Bitten by the Seven he is.

Upgrade it he shall.

Poor he will be.

[Doug Liedblad]

Now to find the correct sized plugs. I love working on this car, it is so freaking easy.

just do a search on 'wiper hole plugs' and you will find many.


I bought some and have not yet used them as the strap for my Brooklands covers the hole.

I have the plugs around.... someplace???