Recommended geometry setup for an SW20 turbo

[Icsunonove]

I am trying to help out a friend who has recently tracked his rev2 turbo and found the handling pretty awful.

Has anyone got any recommended castor, camber and track settings that we could try?

Obviously I could put it back to factory settings but from experience on my AW11 the factory settings aren't necessarily the optimal settings (for obvious reasons).

Cheers in advance

(EDIT: I'll find out what springs, dampers and anti-roll bars are fitted later. Tyres are Toyo Proxes 205/50/R16 rear and 195/55/R16 front)

[Flat Pack]

Tom, I think you could be fighting a losing battle chasing geometry settings when Sy's car doesn't have the right size tyres on it!

Stock tyres are 195/50/15 fronts and 225/50/15 rears (although a lot of people go to a 205 front to combat understeer). I doubt you'll get geometry settings off anyone that'll work properly with the current tyres.

[Icsunonove]

Oops, I think they are 15s thinking about it

EDIT: They are 15" wheels. Tyres are 195/55/R15 fronts and 205/50/R15 rears.

Dampers are Bilstein yellow label, springs are standard, anti-roll bars are standard.

I'm just working out what he's got at the moment. It's not easy because (unlike an AW11) the track is 20mm different front to rear, the offset of the front and rear wheels are different and the tyres are different widths.

[Flat Pack]

Problem is the 205 width rears, not the radius (it might well have 16" aftermarket wheels on it, I just remember at Anglesey in Jan it had 195 width tyres all round and then shortly after 195 fronts and 205 rears).

[jonb-]

Sort the tyres out then go somewhere near factory to start with as the factory setup isn't actually that bad. Castor isn't adjustable on a rev2. If your friend wants a planted front at the cost of a loose rear you can probably run up to -2 camber at the front.

If you use a place like WIM just go stock, drive the car on track then feedback here. You get a free adjustment to fine tune it into your style.

[Icsunonove]

Cheers

I've downloaded a short pdf file which is purportedly for an SW20. Can anyone confirm this is correct as it's just part of a section from a bgb and there's nothing saying it is SW20?

STANDARD SETTINGS
Front camber = -1° 00 +/- 45'
Caster = 2° 50' +/- 45'
Rear Camber = -1° 35' +/- 45'
Toe-in front (total) = 0.1° +/- 0.2°
Toe-in rear (total) = 0.6° +/- 0.1°

Oh and that is from, I think, an NA. Are turbo settings the same?

Cheers in advance...

[jonb-]

Looks about right. If the car is setup stiff you can get away with less rear toe as those settings are designed to stop toe out on squat.

[skinthespin]

Tom,

You will think I am a rooting tooting cowboy for this....

I set my geometry with a piece of string, then I tweeked it over several trackdays until I got it to do what I wanted. I like a really planted front end but like Jon says I have a very wayward rear (oooer), whereas most people would hate my car I think its a right laugh and like the way I can balance it on the rear.

Handling is so subjective I would say go to an open pitlane day with a trolley jack and a socket set and just play.

I love the way my car handles but couldn't tell you what the suspension settings are.

YEEEHAAA!

[Tomiam]

Cheers

I've downloaded a short pdf file which is purportedly for an SW20. Can anyone confirm this is correct as it's just part of a section from a bgb and there's nothing saying it is SW20?

STANDARD SETTINGS
Front camber = -1° 00 +/- 45'
Caster = 2° 50' +/- 45'
Rear Camber = -1° 35' +/- 45'
Toe-in front (total) = 0.1° +/- 0.2°
Toe-in rear (total) = 0.6° +/- 0.1°

Oh and that is from, I think, an NA. Are turbo settings the same?

Cheers in advance...

This is what Ive got printed on my alignment sheet which was done at Wheels in Motion. Hope it helps. These are apparently the default factory settings for an SW20 MR2. Its what was used on mine.

Front Camber Min -1° 20'
Front Camber Max -0° 20'

Front Toe (mm) Min +0.0
Front Toe (mm) Max +1.1

Front Caster Min +2° 15'
Front Caster Max +3° 15'

Front King Pin Min +13° 00'
Front King Pin Max +14° 00'

Rear Toe (mm) Min +0.8
Rear Toe (mm) Max +1.9

Rear Camber Min -1° 55'
Rear Camber Max -0° 55'

[jonb-]

Tom,

You will think I am a rooting tooting cowboy for this....

I set my geometry with a piece of string, then I tweeked it over several trackdays until I got it to do what I wanted. I like a really planted front end but like Jon says I have a very wayward rear (oooer), whereas most people would hate my car I think its a right laugh and like the way I can balance it on the rear.

Handling is so subjective I would say go to an open pitlane day with a trolley jack and a socket set and just play.

I love the way my car handles but couldn't tell you what the suspension settings are.

YEEEHAAA!

[Icsunonove]

Thanks for all the replies

After a load of buggering about with the mathematics I've now worked out where Sy's car is at (it's so much easier on an AW11 with the same track and wheel offset). Whilst it was not done on a weighbridge or scrutineering bay I am 99.9% sure that all the cambers on all wheels plus the caster angle are all within tolerance (although I will recheck it accurately on a weighbridge or scroots bay)

However toe is a different story!

There is a bit too much toe-in on the rear but the front s are toeing out, and by quite a long way!

I will put this right and see how he goes on at the next trackday

Thanks again...

(PS Simon, I always do alignment with string. When I used to prep FF1600s I used to check it at the circuit using optical equipment. I never once had to make any further adjustments. I.E String is accurate as long as you do it carefully)

[jonb-]

I tried toe out at front once, did not like it at all.

[Icsunonove]

I've got my SC slightly toeing out at the front now. On my car it does help it turn in on trackdays , but the downside is that the car is absolutely horrible to drive in a straightline in a crosswind on the road.

But Sy's car is toeing out massively on the front. The rear is toeing in about 1 degree (maximum should be 0.7) but the front is toeing out about 0.8 degrees!

Here's a check sheet for anyone else's use:

[Rowland]

I'm not trying to hijack this thread but...

I'm watching this topic with interest as I desperately need my mk2 race car's geometry looking at.
It's never been checked.
At Mallory on the first corner of the first race a few weeks back I received a knock on the o/s rear wheel.
Since that nudge my lap times were bad and glancing down the wheel doesn't *appear* to be pointing in the right direction. (Almost twisted to appear that the tyre face nearest the front of the car is narrower than the rearward face - if you get me?)

I've tried to illustrate this below:







Now this friend of Toms is running a slightly similar set-up to me with 15's and yellow Billies.
I recall Dino's imoc post from long ago with some figures:







Interestingly when I took this a few years back to my local 4 wheel laser alignment type place, they said they could only work to Toyota's official specification and promptly handed them back with an element of scorn.

So I’m interested in how you get along with your friends mk2 Tom. I may well ask you to have a look a gander over mine please!

Rowland

[Icsunonove]

So I’m interested in how you get along with your friends mk2 Tom. I may well ask you to have a look a gander over mine please.

No problem Rowland. The only slight problem with doing an SW20 with string is that (unlike an AW11) you need to do some jiggery pokery with the raw data (due to different track and offset) and therefore you can't get instant results. I may make a mechanical tracking gauge to use in conjunction with string to speed the process up (for my future use).

For alignment I need only a reasonably flat area. However for camber and caster I need somewhere dead flat (scroots bay / weighbridge).

Is your car still road legal? If it is you could drive over and we could do it one weekend / one evening. You're not a millions miles away either.

[jonb-]

Rowland, I'd have thought the expense of having a decent setup would be well worth it if your racing? £80 well spent IMO.

[MartG]

Rowland, I'd have thought the expense of having a decent setup would be well worth it if your racing? £80 well spent IMO.

Not if the chap doing the alignment refuses to use anything other than stock road settings

[Speedy]

Southam tyres have a full 4 wheel laser alignment setup, and were happy to do whatever setup I wanted on the SC. Might be worth a look perhaps? (Not a bazillion miles away from Rogue HQ)