All Things Mk5 > Members Rides
Black magic Mk5 GTI track car
Banham:
very nice speaker set up :happy2:
fuscobal:
Time for some updates since many happened to the car since my last post
18.03.2011
Car's weight without driver + 55% gas :
Front left > 442Kg
Front right > 515Kg
Rear left > 339.5Kg
Rear right > 279Kg
TOTAL > 1575.5Kg
Car's weight + driver + 55% gas :
Front left > 474Kg
Front right > 530Kg
Rear left > 372Kg
Rear right > 288Kg
TOTAL > 1664Kg
The difference between the 2 measurements = 88.5Kg, meaning exactly my weight :
My weight distribution on the 4 wheels :
Front left > 32Kg
Front right > 15Kg
Rear left > 32.5Kg
Rear right > 9Kg
TOTAL > 88.5Kg
It's interesting to notice that on the left side, more of my weight went to the rear wheel than the front one, meaning that either my CG is more towards the rear than the car's CG (hard to believe), either the rear suspension compresses more under the same weight than the front one.
Weight distribution including driver :
Left - right :
Left = 846Kg > 50.84%
Right = 818Kg > 49.16%
Front - rear :
Front = 1004 > 60.34%
Rear = 660Kg > 39.66%
Cross weight :
Front left - Rear right = 762Kg > 45.79%
Front right - Rear left = 902Kg > 54.21%
If the left - right distribution is pretty good, you can clearly see the cross weights are very different. The front right must be heavier due to the subwoofer from the passenger's feet and the rear left might be heavier because the car is lower on that side. This distribution may also be related to the stiff roll-bars.
Car's CG position on a horisontal plane :
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Car's CG position on a vertical plane :
You first need to weigh the car on a horisontal plane (did that), then you need to raise the rear of the car by say 30-40cm and only weigh the front this time (you need to completely block suspension movement (this is kind of hard to accomplish by me). The position of the CG on the vertical axxis is necessary in order to be compared with the rotation center (CR) of the car wich can be obtained like this > On a transversal section of the car, you draw a line parralel to the lower arm and one perpendicullar to the damper on the upper side of this one. From the point where these 2 intersect, you draw a third line to the point where the middle of the tire meets the road. The intersection of this line with the vertical symmetry axxis of the car gives the CRSe traseaza o dreapta in prelungirea bratelor inferioare si o dreapta perpendiculara pe amortizor plecand din partea de sus a acestuia (la flansa). The closer the CG and CR are, the less body roll you have and the chassis will lean less on both directions !
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fuscobal:
01.04.2011
Installed the following items :
- BSH OCV revamp wich replaces the originl PCV
- USP Fluidampr wich should remove some of the SMF chatter, better dampen the crankshaft's vibration at high RPMs. The Fluidampr has 2738g while the OEM only 1639g.
- USP SS clutch line to better hold the pressure of the hidraulic system.
- Replaced one of the engine mounts with a new OEM one wich looks pretty different than the one that came with the car 5 years ago !
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Uploaded with ImageShack.us
Uploaded with ImageShack.us
Uploaded with ImageShack.us
fuscobal:
18.04.2011
Removed some weight for the incoming Hungaroring track day :
- subwoofer + enclosure > 34.5Kg
- spare wheel + tools > 17.5Kg
- MDF board over the amplifiers > 8.2Kg
TOTAL : - 60Kg from the last track day
To follow :
- S3 front reinforcement bar (aluminium vs steel on GTI) > -10Kg ?
- Odyssey racing battery wich has 12.5Kg (27Kg for my current deep cycle one) > -14.5Kg
- Recaro Poleposition > -30Kg
fuscobal:
07.05.2011
Installed the A3 reinforcement bar, S3 spindles and the Tyrolsport bushings on the R32 front brakes.
Weight :
- GTI reinforcement bar> 7.1Kg
- A3 reinforcement bar > 5.3Kg
- bearing > 3.226-3.240Kg (GTI si S3 are the same)
- GTI spindle > 4.413Kg
- S3 spindle > 2.928Kg
Weight difference on the spindles : aprox 1.5Kg/corner
Weight difference on the reinforcement bars : aprox 1.8Kg (much less than estimated)
Wheel position :
Didn't do any exact measurement but it goes like this :
With 235/35/19 on 8.5J BBS RS-GT rims :
- OEM arms + OEM spindles > the wheel is perfectly aligned with the fender
- TT arms + OEM spindles > the wheel stitches out of the fender by approx. 7mm
- TT arms + S3 spindles > the wheel stitches out of the fender by approx. 10mm
On the road :
The steering feels a little lighter and more responsive but what amazed me the most was the comfort increased ?!?! (while the damping and rebound are as fast as before, the suspension doesn't feel as crashy as before). The only logical explanation I found was the damper works better due to the lower mass of the new spindle !
Install :
As you can see on the pics, the TT arms cannot be installed above the balljoint as on TT because they touch the spindle. I installed them just like on the OEM GTI
Reinforcement bar install :
Unfortunately the weight difference was too small so I wouldn't do it again as the trouble to install it was too big > had to fabricate new brackets and the hook cannot be used anymore also
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