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Feb 05 2013
By: MastrGT MVP Support 41968 posts
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A Tuning Exercise: RUF Yellow Bird '87

[ Edited ]
80 replies 703 views Edited Feb 17, 2013

In a couple of weeks, we will be using a relatively difficult handling car for the Monday Night Racing night. It will need to be tuned enough for all of us to competently drive it and we won't have a lot of time to figure it out. You will need time and patience to experiment and practice, so this is not the typical MNR night, but practice and a good tune will be necessary, this time.

However, why shouldn't we use this as an opportunity to learn from each other? If we describe what we are doing to make the car handle the best it can, and why we think it is the right thing to adjust, then we will have moved forward with our tuning skills instead of just ignoring a difficult car. We also end up with a car we can use more often and a better race night. If somebody likes Porsches, here is your chance to delve into something close to being one, the best that GT has to offer.

Until now, I have reached the extreme limits of some adjusters for the RUF Yellow Bird '87. It needs more help, but how it is adjusted for reacting on some curves now is counter to some other needs, so sometimes I am compensating by using such technics as throttle-control, changing gears out of the powerband, and trail braking, depending on the track. This may be difficult for some controller users to do, IDK, but it helps us learn good driving technique no matter what we use. This car is not going to respond well to you stomping on the gas, so you at least learn patience.

I started by refreshing the car and engine and testing it on High Speed Ring, since the track is relatively short and it has sweeping curves and the S-curves. That will be similar to the real tracks we will use, which will be Spa and Suzuka, and it really doesn't like exiting the tighter curve leading to the finish straight, at HSR. It is better now than when I started, especially with the oversteer, but it still exists. The tune I have is a mixture of who-knows-what and my recent adjustments. However, the car still does not handle altitude changes well yet, when the suspension gets unloaded.


This is not the beast that you fear, but you need to keep the muzzle on it. Can you tame it more?

 


 

Tune #1:

RUF 'Yellow Bird '87' (911)

TCS, SRF & ASM = Off
ABS = 1
Ballast = 194 Kg @ -50
Weight = 1344 Kg
HP = 475
PP = 517

Custom Transmission Top Speed = 172 / 168
ASD = 17 / 17 / 10

Suspension
RH = -27 / -30
SR = 7.5 / 6.0
Damp Ex = 10 / 7
Damp Com = 6 / 5
ARB = 7 / 1
Camber 2.2 / 2.5
Toe = 0.05 / 0.10

Brakes = 6 / 5
Tires = Sports Mediums

I ran 5 laps tonight at both Spa and Suzuka. The car handles reasonably well, now, but you must accelerate in a straight line and the brakes won't stop a freight train. The brakes do their job, if you know your braking points, but the suspension still can come unglued at the crest of the hill at Eau Rouge / Spa, so be careful there. However, I did not go off the track nor spin the car. There was no sign of a spin exiting corner #9 going under the bridge, at Suzuka, either.

 


 

Tune #2:

ABS = 1, all other driver aids = 0

 

Ballast = 175 Kg @ -50 (48/52) total weight = 1325 Kg

 

HP = 473 (518 PP)

 

Transmission:

2.748, 1.700 1.339, 1.022, 0.819, 0.688

Final = 4.00 Top Speed = 199

 

Standard Diff

 

Suspension:

RH = -17 / -15

SR = 8.5 / 5.0

Damp Ext = 5/5 Comp = 3/3

ARB = 7/1

Camber = 1.3 / 1.3

Toe = -0.05 / -0.10

 

Brakes = 2/0

 

Good for a 2'39.9, on Spa; and a 2'18ish, on Suzuka.

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Uncharted Territory
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Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

i know this will sound weird. if you stiffen the rear, and keep the front softer  it'll prolly behave a bit more. i would also tend to keep the ride height even or maybe raise the rear a tad if it gets loose. one thing to keep in mind  with this car is u don't want the rear tires to go first, so a very little understeer might be ur friend. i'll try and get on sometime soon to help everyone find a good, fun tune for this fun little rocket/ jewel of a car.

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Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

oh, i would prolly raise the ride height as well.

 

as for the gears, i would stretch the lower ones a bit more then expected. clacksman's tranny trick would work really well with this type of car i suspect.

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33333Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

I'll be building a couple of these today, one a ground-up tune of my own devising and MastrGT's tune for comparison/experimentation - I already see some things different to my normal approach, look forward to trying it.  I'll be in my lounge much of the day (and over the next two weeks, likely) working on these, if anyone would like to stop in.

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Re: A Tuning Exercise: RUF Yellowbird

[ Edited ]
Feb 5, 2013

MastrGT, just want to confirm, we are goinig to run Sports Medium (not Racing Medium) with this beast?  The massive amount of HP on the rear axle and less grippy tires is going to be a case for Tumble Dryer running on track.

 

no_affiliations, I will have to wait until 4:30/5 PM EST before I can join you.

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Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

sports med should be perfect for what mastr is doing. sport tires are always great for improving one car control.

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Re: A Tuning Exercise: RUF Yellowbird

[ Edited ]
Feb 5, 2013

hey6541 wrote:

sports med should be perfect for what mastr is doing. sport tires are always great for improving one car control.


Yes....This is going to be a great MNR challenge.  I just watched a couple of Ruf Yellowbird at Nürburgring videos on YouTube.  Wow, it looks like really hard work.  (The driver is Stefan Roser. He was the RUF test driver back in the 80/90's. The Yellowbird in that video was set up specifically to show off Stefan's high speed drifting skills... ie; set up to oversteer even more than that model of 911 already did.)

 

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Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

MastrGT wrote: ... on High Speed Ring, since the track is relatively short and it has sweeping curves and the S-curves. That will be similar to the real tracks we will use, which will be Spa and Suzuka ...

I wouldn't say that is true.  Banking puts a much different load into the car than a road course will.

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Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

clacksman wrote:

MastrGT wrote: ... on High Speed Ring, since the track is relatively short and it has sweeping curves and the S-curves. That will be similar to the real tracks we will use, which will be Spa and Suzuka ...

I wouldn't say that is true.  Banking puts a much different load into the car than a road course will.


I was thinking of using GVS or DF (or their shorter variances) to test the tunes later on.  Any other suggestions on the tracks?

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Re: A Tuning Exercise: RUF Yellowbird

Feb 5, 2013

clacksman wrote:

MastrGT wrote: ... on High Speed Ring, since the track is relatively short and it has sweeping curves and the S-curves. That will be similar to the real tracks we will use, which will be Spa and Suzuka ...

I wouldn't say that is true.  Banking puts a much different load into the car than a road course will.



agreed, my tune for susuka will be a bit more loose then the ones for spa or hsr.

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