Converting 0.2° to degrees and minutes

[hspeck]

On my service notes for 1988-1992 Esprit, the camber settings for my front is -0.2°. However, the alignment machine in the shop is in degrees minutes.

I googled and found a table that says the 0.2° is equivalent to 0°12', so 1.0° will be 1°00'.

Is that correct?

And there have been some questions on my mind...

I realised that the alignment settings for the Stevens and the S4 are very different. I know that originally the cambers in the Stevens were not adjustable. What was the difference between the 2 models that the alignment settings can be so different. An example would be the front toes. In the Stevens, the front and rear toes are in toe in positions, but in the S4's the front is toe out whereas the rear is toe in.

Also, I now have the adjustable top wishbone, which I think is the same as that for the S4, and adjustable link at the rear. Thus I can adjust the camber.

Can I do the alignment settings the same as for the S4? 

Do I use 6mm shim washers for the caster adjustment? Or 9mm as per the S4's?

What happens if I use the settings for the S4's?

I have attached the pages for both models.

Thanks.

StevensSuspension.pdf S4Suspension.pdf

[sailorbob]

0.2° is equivalent to 0°12 as both are 1/5 of a degree (there are 60 minutes in 1 degree).

Use the geometry settings for your vehicle as some of the suspension components are different on the S4.

[Erikl]

Other things that may have caused Lotus to change the alignment:

- tire compound evolution and size changes (width and diameter/profile) also pressures.

- brake power changes, I bet the ABS coming in caused most cars to have new alignment settings.

- weight distribution

- rubber suspension bushing durometer changes (i think all same part numbers though)

- engine power changes as it relates to top speed and torque at the axle off the line

- aerodynamic changes?

All said, when you are talking fractions of a degree its very subtle.  I dont think I could feel the difference between o degrees and 0.1 degrees camber or toe. With the rubber everything is moving around any way.  I would bet that most of the really small stuff is just so that the tires will be relatively straight under heavy braking and acceleration.  On the street its just not that critical, on the track you want to adjust for even tire temps.

I have seen when many cars are hooked up to the alignment geo machine, everything set to its tenths of a degree, then take hold of the wheel and pull it, there is enough give in the system to change the reading a 1/10th.  

I like to think of it as Just a little toe in or out etc.  I really think the hyper accurate laser systems that most alignment shops use are over kill, but it does make them easy for a tech to use.  If you are not aligning on one of these machines I am not sure you can measure a 1/10th of a degree that close reputably.

 

 

[hspeck]

Yes, i agree the difference is very little. However the castor is quite different. 

Having said that, most parts that ee order from the private parts specialists are actually upgraded parts from the original, eg my front  wishbones are thee same as those from S4, and my wheels are bigger with much bigger tyres. 

I wonder how all these will affect the handling of the car. 

[Barrykearley]

The chap whom set my car up seemed to state that the chassis, wheel, tyre setup entirely dictates the correct geometry.  I was baffled with hand sketches of parallel planes, rotating offsets, how wheels change angles when turned in relation to each other etc. He fully corner weighted the car and set up per the chassis and what was in front of him. He confirmed the numbers in the book id given him were indeed correct. 
 

This is a chap whom has built chassis for hill climbing - he lives and breathes chassis and alignment. It was very interesting indeed chatting with him - he thought there was too much bump on my shocks and if I wanted to have them revalved he can do that easily as well. Having racked some miles up - the car handles like a complete dream - but I am finding myself agreeing with his shocker comment.

[hspeck]

5 hours ago, Barrykearley said:

The chap whom set my car up seemed to state that the chassis, wheel, tyre setup entirely dictates the correct geometry.  I was baffled with hand sketches of parallel planes, rotating offsets, how wheels change angles when turned in relation to each other etc. He fully corner weighted the car and set up per the chassis and what was in front of him. He confirmed the numbers in the book id given him were indeed correct. 
 

This is a chap whom has built chassis for hill climbing - he lives and breathes chassis and alignment. It was very interesting indeed chatting with him - he thought there was too much bump on my shocks and if I wanted to have them revalved he can do that easily as well. Having racked some miles up - the car handles like a complete dream - but I am finding myself agreeing with his shocker comment.

I just had mine corner weighted today. 

Waiting for the person to send me the readings. 

He also said that the geometry depends very much on the setup of the car, and he has to drive it before he can advise me. 

I have 17" in front and 18" wheels at the rear, with much wider tyres than original, so he said the geometry may not be per specifications now. 

He needed some information from me, like the spring rates, which I did not know and I have to ask the supplier of my shocks. 

I have been having issues with the Esprit's suspension settings since I have gotten the car, and have not been able to find a workshop who follows the manual's instructions even after i repeatedly told them about it. 

Today, I saw that they used shim plates on both sides of the top wishbone to ball joint when they had only added 1 shim washer at the rear of the top wishbone to chassis. Which was not in accordance with the manual. I will probably have to find a shop where i can look at and check what they are doing. 

I have found 1 shop that does alignment for classic minis, hopefully he will be better. 

[hspeck]

An update to this

I have replaced my top wishbone with a new set from SJ sportscars as someone has grinded the protrusion away as I have posted in this thread -

I forgot to take photos, but I now have the correct offsets instead of washers.

Whilst replacing the top wishbone, I realised that I am unable to follow the instructions as per the original manual for the X180. In the manual, the instruction was to have 6mm of washers between the front and rear of the chassis at the top wishbone pivot stud. I added another 3mm washer to the rear to set the castor, and so added a 3mm shim plate to the cross end at the top ball joint. However, when I tried to tighten the nuts, somehow the wishbone arm was slanted, resulting in the big washers pressing on to the bush. 

So what I did instead was to follow the instructions for the S4's. That is, 9mm of shim washers at the top wishbone and chassis, and 12mm shim plates between the top wishbone and top ball joint.

I was then able to properly tighten the studs and bolts on the top wishbone.

So I think, despite my Esprit being a X180, since I am using the top wishbone that is similar to the S4's, we have to follow the instructions for the S4 instead of for the X180.

I hope I am able to express myself clearly.