FCT Challenge - 'Der Neunelfer' TWISTED!--CLOSED

[Hoplee]

"Der Neunelfer"
FCT Challenge
Restrictions: B-Class 1973 Porsche 911 Carrera RS
Track: Mugello Long

Cooter cocked his one good eye at me and spat, 'What would a nun be doin to an elf?'

Gentlemen, welcome to the latest FCT Challenge, "Der Neunelfer". The objective of this weeks challenge is nothing less than to de-mystify the rear-engine, rear drive type. Mugello Long course will be our home for the week, and your new best friend (worst enemy?) is an old 1973 Carrera RS.

I'll be adding my own theories concerning the handling of this unique sports car as we move along, but the first thing I'd like to do is to let the car speak for itself. PorscheH6 has agreed to share a really great tune he sent me for the RS in B-Class, and I hope you'll be as impressed with it as I am. It very well may be as quick as the Dino at this track, and is very capable of a mid 1:50s time.

Hop's current best, you ask???
118.115 (0.4 behind the Dino for now)


1973 Porsche 911 Carrera RS
FCT B-Class PI 700 vPorscheH6
207hp/188lb-ft
1803 lbs


Upgrades
Race Avon 195/55R17 & 225/45R17
Race Platform and Handling
Race Weight Reduction
Forza Front Bumper
Forza Rear Bumper

Settings
Tires   31/30
F.D. 3.92

Camber -0.8/-0.8
Toe      0/0
Caster   5.6
ARBs   14.2/10.06
Springs   257.8/289.3
Ride      7.4/7.5
Rebound   6.1/6.4
Bump      3.6/4.0
Aero      75f/NAr
Braking      50% Front Bias / 90% pressure
Differential   27%/23%


THE TWIST!

Gentlemen, I have an announcement:

Pack your cars and break out your wallets. Kiss Mugello goodbye, cause I've got track time lined up for us outside Monterey! Get this, there's a PCA swap meet going on at the same time if anyone's got money to burn...

Boy, I wish we could be there for the Rolex Historics in a couple of weeks, but that dance card filled up a long time ago!

~

FCT Challenge 'Der Neunelfer' TWIST summary.

Car restrictions: A-Class, Rear-Engine, Rear-Drive, Porsche
Track: Laguna Seca
NOTE: Track times for B Class Mugello and A Class Laguna Seca will be added together for the total result.

PS: I'll be posting the build that PorscheH6 sent me of the Carrera RS in A Class shortly. His time is the first one to beat!

Porsche H6      A Class '73RS     1:24.182

1973 Porsche 911 Carrera RS
FCT A-Class PI 850 vPorscheH6

Upgrades
Race Avon 225/40R18 & 255/35R18
Race Platform and Handling
Race Weight Reduction
Forza Front Bumper
Forza Rear Bumper
Sport Intake
Race Cams
Sport Block

Settings
Tires   29/28
F.D. 3.47

Camber -0.8/-0.8
Toe      0/0
Caster   5.6
ARBs   11.70/16.26
Springs   230.6/295.4
Ride      7.6/7.6
Rebound   5.4/6.8
Bump      3.3/4.0
Aero      74f/NAr
Braking      46% Front Bias / 110% pressure
Differential   45%/43%


Muscle-Inc General 911 Projects Reference



FCT Project - S-Class 1995 911 GT2
http://www.muscle-inc.net/index.php/topic,330.0.html

FCT Project - Spiny's ALS Spec 911
http://www.muscle-inc.net/index.php/topic,110.0.html

FCT Project - Hekalite's B-Class '73RS
http://www.muscle-inc.net/index.php/topic,139.0.html

FCT Project - Yellow Bird tribute car A Class 911 Turbo
http://www.muscle-inc.net/index.php/topic,300.0.html

JEi Project - U Class 997 GT2
http://www.muscle-inc.net/index.php/topic,542.0.html

JEi Project - S Class GT3RS
http://www.muscle-inc.net/index.php/topic,223.0.html

Smokey's Garage - "Porsche Love"
http://www.muscle-inc.net/index.php/topic,698.0.html

Spanky's Speedshop - A Class 911 (996)
http://www.muscle-inc.net/index.php/topic,648.0.html

Ske's Workshop - S Class 911 (997 Turbo)
http://www.muscle-inc.net/index.php/topic,693.0.html

Feuerdog - Porsche RR Suspension Tuning (996 and 993)
http://www.muscle-inc.net/index.php/topic,537.0.html

Carn - 997 S Class Builds
http://www.muscle-inc.net/index.php/topic,726.0.html

Muscle Inc member builds developed during this challenge

bimmerloveree36 - 1982 911 Turbo "930"
http://www.muscle-inc.net/index.php/topic,854.0.html


Advice fur der Neunelfer
~OR~
Why is my 911 trying to kill me?


The best advice I can give about driving the 911 is this:

Make each turn only ONCE!

The weight distribution, front to rear, is what attracts the most attention when discussing 911 handling dynamics. However, the most important thing for the driver to control is the transfer of the weight of the vehicle side to side.

The side to side transfer of weight during cornering is really the root of the whole problem with the 911. For example, in a MR or FR car such as the Ferrari Dino or Dodge Viper, I can commit to the inside line of a given turn, suddenly change my mind, and swing onto the outside line, without any drama and at just about any given moment. If you try this kind of nonsense in the 911, it will try to kill you.

Therefore, I recommend that you brake ONLY ONCE and IN A STRAIGHT LINE.  a few yards before the apex, make your cut and transfer weight to the out-board most two tires. Keep your weight on that side of the car and adjust your line only with throttle input until you see your line out. Stay steady with the steering to keep the weight settled where it is, and positively rock solid on the gas as you exit.

Here's why:

->The 911 has excellent turn-in response under braking and it's easy to get into a slight (or NOT so slight!) drift situation if you try and start your trail braking too early.

->The reason you want to use only the throttle to adjust your line for a few yards just before the apex is to control steering. If you hit the gas, the weight comes off the front, decreasing front end grip, and that's why you'll get roughly proportional 'under-steer'. If you let off the gas, you'll get roughly proportional 'over-steer' effects by increasing front end grip. It's important to note that dramatic changes in throttle input almost always produce 'snap-oversteer' in a RR car, by overwhelming available grip at one end of the car before the other.

->The weight transfer to the rear as you accelerate will absolutely plant the rear end on corner exit. It will also swing the tail slightly outside, helping you to point the car towards daylight. If, however, you let off the gas during corner exit, all that weight is going to come off the rear and it's going to understeer if you're going slowly enough, or if you're going a little faster it will try and swing around you as weight moves towards the front end and increases steering effects vs steering input. It will also be unkind if your steering input is dramatic enough to upset the side-to-side weight transfer of the vehicle, often with humorous results.

-MAKE EACH TURN ONLY ONCE!

Leaderboard:

Driver	Mugello Long	Laguna Seca	Car	Total
PorscheH6	115.968	84.182	'73 911 Carrera RS	200.150
Serial	115.878	84.813	'73 911 Carrera RS	200.691
landstuhltaylor	116.560	84.827	'73 911 Carrera RS	201.387
Drift2XL	116.588	85.394	'73 911 Carrera RS	201.982
Ske	117.203	85.827	'73 911 Carrera RS	203.030
Hoplee	118.115	86.547	'73 911 Carrera RS	203.973
Bimmer	117.815	86.477	'82 911 Turbo	204.292
LarryCR	117.832	87.266	'73 911 Carrera RS	205.098
BBQPete	118.509	87.504	?	206.013
PureStankonia	119.553	87.916	'82 911 Turbo	207.469
JuanofMany	121.477	89.687	'73 911 Carrera RS	211.164
Technobear	122.282	90.729	'73 911 Carrera RS	213.011
Placard Rat	117.990	x	x	x
ORG63	119.080	x	x	x
fndrbndr	119.545	x	x	x

[Ske]

This'll be interesting as I've never even touched that car.


*off to build one*

[PureStankonia]

Same here, never had one.  Thanks for opening the garage some more Hop.

[BarbecuePete]

Will be interesting to see what the tune is like, I've not built using someone elses tune before..

Also we'll include these in the Sockmonkey Saturdays if enough people have the car built up..

[Ske]

Actually I had one built up - with street weight reduction and 220hp on goodyear slicks.

Did a "5 minute tune" and set a 117.564 in my first flying lap.

I think I found a pretty good tune which is stable yet definitely retains that RR flavor.

The basic tune is:
28/28
4.50; 2.50/1.40/1.00/0.80/--/-- (my patented 4-speed box )
-0.8/-0.4; 0.0/-0.2; 5.5
20/12
250/300; lowest+1
10/12; 2.4/2.7
min/na
60/115
25/20

Not sure if I tampered with the ARBs slightly (1-2 clicks in either direction) but that gives you an idea.

[PorscheH6]

Alright guys, I've managed to crank out a 116.695.

I hope you guys enjoy the car - It's my short track assault car. Usually can hold it's own to mediocre Mugen Integra drivers. 

[Drift2XL]

PorcheH6,

We have some ...ahem... older members, whose eyes aren't as good as they used to be.

We normally put our LB times in bold so its easy to keep up with.

I know your new. So its no problem. But the help would be appreicated. 

[PureStankonia]

Eeked out a 119.663.  Only time in 20 laps in under 120.  Long track, had quite a few times seeing green splits but couldn't pull it all together but once.

edit: Used a placard rat tune from an r3 911rsr that I had saved.

[PorscheH6]

But the help would be appreicated. 

Not a problem! Will keep in mind for next time.

[Drift2XL]

I wanted to get some seat time before I got to working on the LB so......

'73 Porsche 911 Carrera RS

116.803

I have a love / hate relationship the 911's.    I love to hate them....

Nah, I just don't spend that much time driving them. I haven't learned how to "tame the pendulum" just yet.

Decent tune from previous FCT challenge. I bound the rear up with front rebound to keep the weight transfers in check. Feel's good. Could go a little further, but I need to get consistant with the car first.

I can't wait to try out your tune H6.

I know if Hop is impressed with a tune, its really good.

[larryCR]

My initial try is with full WR, Avons, aero, and the lightest wheels I could find to stay at B700. Only really minimal tuning so far. I lowered the FD number a bit which gives me max 2nd, 3rd, and 4th revs at about the right points on the track. -0.8/-0.7 camber, +.1/-.2 TOE, minimum aero, and everything else the way it came out of the box.

118.240

I need to spend a lot of time just getting a feel for the response time of that big lump hanging out the back. No point in WB, SWR, and damper changes at the point I'm at right now. I wouldn't know if I was helping or just learning to drive.

[Serial]

I wouldn't know if I was helping or just learning to drive.

Larry, this is the statement of the decade.  This reminds me of one of the best posts in history, courtesy of Big Mooing Cow (BMC).

If you have not read this (long) post, please take a few minutes or so and read not only BMC's comments, but some other comments as well.  A lot of the thread posters are Muscle-Inc.net members, either past or present.

Please read if you haven't already:
http://forums.forzamotorsport.net/forums/thread/442058.aspx

And to get back on-topic-ish...I am hoping to get some lap times in with this car/track combo sometime this weekend.  Although Mugello and I are not currently on speaking terms. 

[Serial]

Okay, so I took what Larry/BMC/myself were saying earlier and put it into action.  I took PorscheH6's upgrade list, and a stock tune (with the exception of tire pressure...28/27).  I ran some laps with this stock tune until I was comfortable with the lap.  There is definitely still a couple of tenths left even in the stock tune.  Once I begin to tune the car, I think another 0.5-1.0 will be found because I should be able to get on the gas earlier and not have to modulate so much in the corners.

Time for now (tire tune):
116.486

[larryCR]

Serial, thanks for reminding me/us of BMC's article. I hadn't read it in a long time and it is a good one to review once in a while.

And thanks for showing the way with this car. Impressive time! I hope you find the time to tune on it too.

Edit: I took Serial's advice (from now and previous), went back to the stock tune + pressures, turned off all assists (I usually drive with ABS, traction control, and the braking line) and just started driving and learning. 12 laps in I managed a 117.989. Still in the minor leagues, but I've done worse with a lot more help from the game.

[Drift2XL]

Holy crap Serial!

Stock tune?  .....   And another second off?   Don't know if I can keep up this time.

My time was tuned and that's about all I got. Guess I have to play with fire and get aggressive with the trailbraking to get closer (not a good idea w/ 911).


H6,
I tried out your tune. Best I could get was a 118.4. There are a few things that I would change.

First is tire pressures. Lowering would get a bit more grip. I didn't lower them during the test time with your tune. Had to run. But I would say down to 29/28 or the other way around. Just more grip available with the lower pressures.

I also feel like there is a bit of understeer and that it is fighting me a bit more than I like. It might be aero induced. Might not.

My one question is "Do you use a wheel or controller?"

I can see a difference in fine inputs with the wheel vs controller. It would definitely answer the other tuning questions I have.


Larry,
You're using a 911 as a no assist trainer?  You are a braver man than I, sir.
But I'm a no assist guy too.