Q's for the KW Experts

Originally Posted by Pax

To add a bit of confusion into the mix, I got opposite values from an authorized Alfa dealer back in February...:

Front toe: -0 deg 8'
Rear toe: +0 deg 13'

I.e. toe-in at the front and toe-out at the back.

No, both figures will be toe-in.
-ve toe-in giving you toe-out.


There is no way you want toe-out on the back of a FWD road car!

i had my kw v3 last week and they have totally changed the car and made a real improvement

Originally Posted by David C

No, both figures will be toe-in.
-ve toe-in giving you toe-out.


There is no way you want toe-out on the back of a FWD road car!

Well, the protocol says just what I wrote: Both front and rear the word "toe" is used before the values I gave. It did not say "toe-in" or anything else.

I am really not quite sure what to say to the alignment guys tomorrow... What do you say about 0 toe at the front and -0.5mm at the back? It could be nice with some straight line stability when accelerating.

DavidC is defintely right about "toe" by default meaning "toe-in".
You can see this in the explanatory pictures in the photo below - there are little arrows indicating the angle concerned.

Heres a photo of the allignment printout from the Allignment centre for my last settings from Autodelta.
This was with the car at standard ride height, I generally lower it 20mm for track days.

[EDIT: These settings were for a car with poly bushes front and rear. ]


Mid-point between the indicated ranges is optimal, so give that to the guys NOT my actual measured values that are printed in large numbers inside the boxes.

e.g. The allowed range for front toe was [minus 0 deg 7 min] to [minus 0 deg 02 min]
Both of these settings indicating very slight toe-out.

So the mid point would be [minus 0 deg 4.5 minutes]
http://i30.photobucket.com/albums/c3...3344_IMG_2.jpg

As you can see from the photo there is a relatively larger positive toe-in setting at the rear.

Interestingly a previous allignment sheet I had for a (relatively) less extreme but still heavily modified version of my car showed that the front toe was set exactly to 0, and the rear toe-in set to 0 deg 14 minutes.
Personally I would recommend the ones that I have in the photo more, and imagine that this was based on some refinement over time by Autodelta.
BTW Straight line stability is just fine with these settings, better than standard.

Hope this is useful

Cheers,
TB

Thanks David and TB, most useful!

I will go for these settings tomorrow then:
Front toe (in): -0 deg 4,5'
Rear toe (in): +0 deg 13,5'

Originally Posted by David C

There is no way you want toe-out on the back of a FWD road car!

It is common with Toe out on FWD Race cars but as you say its not a good idea for road cars.

But you can give a road going FWD a little bit toe out to decrease the stabillity of the rear tyres and counteract understeer. I think this works 'only' if the front wheels are also set to the same thrust line as the rear tyres Ie. minimizing thrust angle. This is again theory, and not something which i know would work or not on the GTA.

For front Toe it is worth considering if you have stock or poly bushes. Since TB's setting by AD is based on poly bushes, and because i have every confidence that AD would have taken this into consideration, then i would think Pax should set his with a bit more positive front toe then TB. A powerfull FWD like the GTA on stock rubber bushes, will create quite a bit of Toe in when the wheels are laden.

Heres a good link on this stuff:

http://www.ozebiz.com.au/racetech/theory/align.html

Yes some Toe-out on rears for genuine FWD race cars is possible.
If you have been driven hard in a FWD race car on track by a pro, you will realize that essentially the rear is set up to be unbelieveably loose, its like a shopping trolley at the back.

Not really something you want when slamming on the brakes on a blind corner on a wintery evening when you notice an accident ahead.

Peter can you clarify - Did you mean "Pax should have more toe-out than my settings"?

It is true that the front wheels of a FWD car tend to *toe-in* under power.
Probably poly bushes reduce that effect slightly - good point I forgot about that!
So yes he could have slightly more toe-out I suppose, this would lead to the figures that PAx's dealer had - which seem fairly sane to me.

However I think Pax would still be fine with the settings since
when my first coilover kit was fitted by AD I didn't actually have poly bushes on the front and AD specified slighty less front toe-out than the (still modest amount) they do now. This was for a more powerful car than standard so it is possible that AD might have been playing a bit safe to maximize straight line stability and later changed to slightly more toe-out to increase turn-in.
The car still handled great though.

For Pax I would say that it is a choice between balancing
tyre life and slightly improved straight-line stability Vs very slightly reduced initial turn-in .

To be honest the GTA turns-in so quickly I don't think a minor reduction affects the handling too much.

Cheers,
TB

Originally Posted by Peter K

For front Toe it is worth considering if you have stock or poly bushes. Since TB's setting by AD is based on poly bushes, and because i have every confidence that AD would have taken this into consideration, then i would think Pax should set his with a bit more positive front toe then TB. A powerfull FWD like the GTA on stock rubber bushes, will create quite a bit of Toe in when the wheels are laden.

There is also the issue of bump steer.. i have (i think) identified that my car does create bump steer. I've been told (not verified) that the 156 creates Toe Out under Bump Steer. Depending on how many parameters AD have taken into account including the fact that you, TB - seriously Track your car , they might have give your car a bit more Toe-in on this account.

I would think the stock torque of a GTA already creates maximum flex on the bushes, Ie max added Toe-in, but of course there might be more flex when you really hammer it in your beast!

I'm just saying that unless Pax tracks his car often, or do a lot of Motorway driving, then a Toe-out setting perhaps like the latest updated numbers or at least a bit more then yours is the best solution for him. I know the roads where Pax lives, so i would personally wellcome a bit more turn-in response on those fantastic B-roads in the area.

TBH, i suspect the AD guys gave your (TB) car more Toe-in then usual because of it's speed potential. It would be the prudent and safe thing to do.

Sounds reasonable to me.
Pax if you are watching, perhaps Peters suggestion of a little more toe-out at the front is sensible.

If you have already done the allignment don't worry it will still be just fine

This season I have run on stock suspension, the Superleggeras ((8*18 225/40 Michelin Pilot Sport PS2) and the settings I mentioned:

Front toe: -0 deg 8'
Rear toe: +0 deg 13'

I.e. a little more front toe out than Autodelta, back is identical. With this experience I would welcome a little more stability even if the tradeoff would be some less turn in. The V3s have enhanced the turn in very much, so I think I could nag some turn in with less toe out without it being a disaster I'll see how it works out this weekend, I will do a 500 km trip towards Gothenburg and back with the new settings. Let's just hope rain will not spoil the fun

Nice that you like our roads here Peter, there really are some excellent roads near Ring Knutstorp. I have enjoyed the GTA around there quite a few times.

No doubt your car wil drive excellent with either of the settings we have been scrutinizing in such detail. I know some of them who drive serious race cars fitted with steelbushes, camber plates, caster plates and what have you, laugh at us when we discuss road car suspension geometry in detail.. Their point being, that it is so soft and inaccuarate, that under race like conditions, the wheels are bouncing all over the place. They are probably right too......

BTW, on my KW 2's for road use, i am now running with one full turn back from hardest damper seting at the front, and 3/4 turn back at the rear. This took care of the dash rattle, so that was a good trade-off i thought.

Originally Posted by Peter K

I know some of them who drive serious race cars fitted with steelbushes, camber plates, caster plates and what have you, laugh at us when we discuss road car suspension geometry in detail.. Their point being, that it is so soft and inaccuarate, that under race like conditions, the wheels are bouncing all over the place. They are probably right too......

Hehe, don't make us look stupid now Peter. But what the hell, one needs to spend ones time on something, be it knitting or suspension geometry discussions.

hehe..no i don't feel stupid at all.. in fact being such a stickler for handling feel and details have paid off for me personally. First time i took my brand new GTA to the Street i felt something was not right. Had my garage take a look and they took a test drive. They came back said all was fine, in fact "it drove fantastic" Damn i thougt.. So I took it to a specialst who had it 4-wheel-alligned and thoroughly measured They found a serious Caster misalignment between the two front wheels...Went back, report in hand and got it fixed.

Drove it for about 3000 km, then felt another handling problem this time releating to what I thought was a problem in the front left hand side wheel or suspension. They had a look at it, took it out for a drive and came back said it was fine, in fact "it drove fantastic"...... Double Damn i thought..... Drove the car home but could still feel it. It got worse, so I took it back a few weeks later and told them to check it again. They sort of looked at me like i was a fool, but promised to give it another look over. This time they found a totally worn out wishbone. (left hand side)

On the other hand, i remember once during some Alfa meeting this young guy who was totally chuffed with his 156. He just had it lowered it on stock dampers. Anyway he went on about how great it handled through corners with thw new springs. Few months later a buddy of him told us that not long after that meeting, the guy had taken his car for MOT inspection where it failed miserably with two defective dampers and a worn out steering rack! I think the guy honestly thought his car handled great, but probably had no idea how a car was supposed to handle. Not saying I know this either, but it certainly suggests that some basic suspension knowledge at least helps.

Originally Posted by Pax

I set the car up to the original ride height both front and rear,

Is it possible to leave the original height with KW2? Or it has to be lowered a bit? I'm thinking about stiffening but without lowering. And I'm considering KW2.

Hi there,

I have not measured if you clear the distance range recommended by KW (in the installation manual), but in practice it should be no problems at all running original ride height.

I have mine lowered only a bit (I think it is about 1.0 cm) due to the already low ground clearance on the 156 GTA.

Zbenio,

You might benefit more from uprated Anti Roll Bars. For some reason or another the 147 GTA is very prone to sideways roll, I suspect it could be a combination of the higher profile and shorter wheel base (compared to a 156 GTA) but it's just a theory.

PAX: thanks for your reply, it's good news to me
Peter: yes, I'm thinking about this mod, too. On my wish list are: ARBs, coilovers and LSD. Then I'll be the owner of GTAl dente

Hello All,

I'm ready for some more wheel geometry discussion

For a month now I have had the Q2 and front strut bar fitted, and I also have lowered the car some more. After the Q2 fitting I revised the toe settings to a bit more aggressive values:

Front single toe: -0 deg 4'
Rear single toe: +0 deg 4'

I think this has been a step in the right direction: turn in has not become noticeably worse, lift off oversteer has not in any way become exaggerated, mid turn balance (steady-state) has become less understeer biased. High speed sweeping bends are still just fine, no nervous rear end. However, I think it would be nice if the mid turn understeer bias would be even more reduced.

How to achieve this with the toe settings (and still be safe to drive)? Less front toe out, maybe parallel? Crazy enough to reduce rear toe in even more?

I'm running with zero degrees rear toe now, and am very happy with it.