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Author Topic: TT lower arms and geometry changes  (Read 20401 times)

Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #75 on: May 18, 2011, 11:46:47 pm »
Well, greasy roads and the chance to explore limits at sensible speeds, well yep I can provoke oversteer, but easily balanced and the poise balance and behaviour is text book stuff, anyone watching would be fooled into thinking I was talented. It's coming close to reminding me of a FWD equivalent of an E30M3 (I had one for many years and was complimented on my driving around spa by a pro, I didn't tell him the reason he couldn't shake me off with slicks in a very low class BTC of some equivalent was the sublime chassis and near tyres as good as his slicks - Dunlop DJ01's)

This car has moved into the great category, I'm gobsmacked. If I'm slower on the track I'm happy too. It's a point and shoot roadie to enjoy day to day, I am actually excited about the drive to work tomorrow...... which I never expected from a GTi  :wink:
« Last Edit: May 18, 2011, 11:48:49 pm by Carrera2RS »
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Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #76 on: May 18, 2011, 11:49:58 pm »
I have had two glasses of wine since getting home, so my view might be more balanced in the morning !
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Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #77 on: May 20, 2011, 07:26:21 am »
Gents

I thought it might be helpful to set out the actual figs (recognising my last setup showed very small differences when back on the same rig, so accuracy to 2-3 mins is clearly a pointless challenge)

Front

Ride height 338 mm
Camber L -2 deg 10 mins, R -2 Deg 0 mins
Toe L - 6mins, R - 6mins (toe out)
Caster L 8 deg 13 mins, R 8 deg 14 mins
SAI L 16 deg 36 mins, R 16 deg 21 mins
Bilstein PSS10 setting 3/10
Neuspeed 25mm bar full soft
WALK
Tyre pressure 35 psi after a 20 minute normal journey (32.5 cold)
Tyre Pirelli P Zero 225/18 92Y XL MO

Rear

Ride height 324mm
Camber L -1 deg 37 mins, R -1 deg 30 mins
Toe L 6 mins, R 7 mins (toe in)
Bilstein PSS10 setting 4/10
Neuspeed 25mm full hard
Tyre pressure 33.5 psi after a 20 minute normal journey (31.5 cold)
Tyre Pirelli P Zero 225/18 92Y XL MO

I will still look to raise by some 5mm or so, mark very carefully the collars and experiment a little. I was looking to move from 335 F, 320R to 340F, 325R it didn't quite hit those heights after settling over a few hundred miles

« Last Edit: May 20, 2011, 07:30:44 am by Carrera2RS »
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Offline the bruce

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Re: TT lower arms and geometry changes
« Reply #78 on: May 20, 2011, 08:10:36 pm »
Better go for 330 to 335 mm rear.  :wink:
I suspect I had the problem of too less suspension travel by myself when
I was as low on the rear like you.
This may have caused the sudden massive oversteer I had on 180° corner.

If you're going to do a new alignment try toe in on front.

 :driver:
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Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #79 on: May 21, 2011, 07:33:39 am »
Bruce, tks

I will try raising the rear to 330mm.
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Offline the bruce

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Re: TT lower arms and geometry changes
« Reply #80 on: May 21, 2011, 12:16:05 pm »
I have to add from the view of aesthetics I prefer the side skirts being horizontal.
Sadly if you adjust the suspension due to this the travel will be critical at rear

 :sad1:.

This depends on the stiffness of your suspension (springs, ARBs, dampers) of course.
« Last Edit: May 21, 2011, 12:17:56 pm by the bruce »
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Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #81 on: May 21, 2011, 12:58:16 pm »

I couldn't agree more, very happy with the look at 338/324

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Offline the bruce

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Re: TT lower arms and geometry changes
« Reply #82 on: May 21, 2011, 01:46:07 pm »
I currently have 337 front and 330 rear. I had 337 front and 320 rear before.
Even with 320 rear my ''side skirt line'' wasn't level.
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Offline fuscobal

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Re: TT lower arms and geometry changes
« Reply #83 on: June 10, 2011, 08:54:10 pm »
Got to change my steering rack and things got much better no. I've also measured the ride heights to be 343F and 345R. Dropped the rear to 337 and set the suspension to 8F and 7R in order to dial out some of the oversteering I was talking about ! Will also try 2.1bar on front and 2.0bar on rear as opposed to 2.3F and 2.3R wich wore my Kumhos more on the center !
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Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #84 on: June 11, 2011, 07:32:00 am »
I am now running 4-5mm front and rear. Measuring 342-343, 329-330

I did this and changed tyres for new Pirelli Zeros (The same as before) again set at 35F, 33.5R when warm (33, 32 cold) The suspension was reset...... due to changing the bottom mount, only the tracking front and rear changed, now measures :

Front
Camber : -2 deg 4 mins, R -2 deg 10 mins
Castor L 8 deg 20 mins, R 8 deg 8 mins
L -0.2mm, R- 0.2mm (out)

Rear
Camber L -1 deg 36 mins, R -1 deg 29 mins
toe L 1.0mm, R 1.0mm (in)

At present it is good, but not quite as good in terms of balance and grip. I am putting a few miles on new tyres before concluding

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Offline rex

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Re: TT lower arms and geometry changes
« Reply #85 on: June 11, 2011, 09:02:30 am »
From what the bruce told me, toe out is not the way to go...
I had toe out (0.05' on each side) and now I have toe in (0.10' on each side). The car is much more responsive. I did not have the chance to see if this new toe setup is better for the track, but I suspect it is... I will test it on the 21st..

Here is my setup:

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Offline fuscobal

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Re: TT lower arms and geometry changes
« Reply #86 on: June 11, 2011, 09:40:37 am »
Carrera, I also find strange your rear negative camber wich is the smallest I've seen. Most guys run -1deg50mins with rex having even more at -2deg10min. I will also increase rear a little to -2deg to reduce oversteer. Tour -1deg36min could lead to a happy tail !
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Offline the bruce

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Re: TT lower arms and geometry changes
« Reply #87 on: June 11, 2011, 03:05:17 pm »
I run 1°10' all four wheels at the moment.
I still have the S3 arms and wanted to give it a try.

Found a very interesting article. Although about comparing
simulations sw vs. seven-post machine there are some
nice data shown. The stock front suspension bushes flex
causes enormous shift in toe especially on the outside wheel:

http://tesis-dynaware.com/fileadmin/Downloads/Referenzen/VW_ATZ_Messdatenbasierte_Fahrdynamiksimulation.pdf


see 'Bild 1' right below (toe) and 'Bild 8' (steering angle)
« Last Edit: June 11, 2011, 03:16:45 pm by the bruce »
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Offline the bruce

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Re: TT lower arms and geometry changes
« Reply #88 on: October 20, 2012, 02:20:03 pm »
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Offline Carrera2RS

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Re: TT lower arms and geometry changes
« Reply #89 on: October 24, 2016, 08:12:39 am »
Interesting, I am now playing with suspension settings on an F10 M5, checked to remember my journey with the Old Golf, I wonder how She's getting on now  :happy2:
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