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Micke wrote:Maurizio. To choose which diff to use you should know the rpm limit you want to use. Tire size of course. And then the power you have to determine the speed. I'd say if you don't want to rev high a TS box should be fairly OK on the ring.

Micke,

The problem at the moment is that I don't have enough power for uphill (Kesselchen towards Steilstrecke). It is 4th for 90% and >5000 rpm and when I up-shift to 5th the car has no more acceleration even drops down in rpm . On the fast bits off the track I never run into the limiter in 5 th (I chicken out or am not fast enough )
And there are some corners now I could go back to 2nd gear but normally I don't, I only use 3,4,and 5 th.

I use 195/50-15 now, before I used 185/55/14 which was a bit better.

I even did a scientific approach, I calculated drag vs engine torque and looked what is left at the outside of the wheel to accelerate, see attached file.
And the 1.8 diff looks nice.


But still in doubt, low on budget, so 1.8 diff with no lsd ....will it work good enough?
Is a lsd needed on the ring, I'm not sure.
Looks like it helps a lot at the twisty bits where my 75 is made for and I have the most fun.

But on the long term:
- If I make the car lighter (there is a lot which still can be done).
- Get better in my driving and pick up some more speed.
- Find the old sock with coins and invest in more power.

==> will the 1.8 diff become to short???

Or a realistic approach...by then I still can put in a ts diff.

I'm travelling right now and cannot calculate throughly but I have some short notes.
1) The 4.3 diff is about 5% shorter so you get ~5% more force up Kesselchen. Not a really big impact.
2) Please consider doing whatever necessary to get speeds >200 km/h not to bore yourself to death on the ring. Don't start preparing a loser car.

As a conclusion I'd say just install the std TS box if you want to do it cheap.

Made a couple of charts to show the difference in gearboxes and rpm (i.e. shift-points)

Kevin: You need to look at the specific track and try to match the corner speeds to the gearset, very difficult to give advice without having corner for corner speeds. I'm in the same kind of hell myself right now in trying to decide but since I'm redoing my whole car I have no starting point what so ever.

Maurizio: Stock TS have a rev limiter of 6300rpm, right?
From my very limited experience I'd say that an LSD on the ring with a stock TS engine is totally unnecessary, no slow tight corners in sight! Likely hood of a torque related loss of traction in high speed corners = 0.

And this is my theoretical setup.

OMG!
I hope you are not seriously considering some 190 km/h top speed.

Of the 3 cars I've raced on the ring 2 had LSD and one not. The one without was FWD so it's not exactly the same (or even close) but I can say it made a hell of a difference. In a later race we got a LSD for it and driving was much more efficient.

Just to convince you I checked the datalogger file from last summer.
Alfa 147 Diesel from rental company. All luggage in the trunk and all season tires.
Schweden (Mats) Kreuz 192 km/h and Fuchsröhre 196 km/h so whatever you do - don't aim for lower than that.

Micke wrote:Just to convince you I checked the datalogger file from last summer.
Alfa 147 Diesel from rental company. All luggage in the trunk and all season tires.
Schweden (Mats) Kreuz 192 km/h and Fuchsröhre 196 km/h so whatever you do - don't aim for lower than that.

I remember seeing 200Km/h (indicated) with one of Rons TSes at both Flugplatz->SX and Fuchröhre so I totally agree.

With a stock rev limiter that is...


btw, there was time to have a long look at the speedo in Fuchsröhre because the streamer at the top of the windscreen effectively blocked ALL view of the track...
Not always a good thing to be tall I guess.

Mats wrote:

Micke wrote:Just to convince you I checked the datalogger file from last summer.
Alfa 147 Diesel from rental company. All luggage in the trunk and all season tires.
Schweden (Mats) Kreuz 192 km/h and Fuchsröhre 196 km/h so whatever you do - don't aim for lower than that.

I remember seeing 200Km/h (indicated) with one of Rons TSes at both Flugplatz->SX and Fuchröhre so I totally agree.

With a stock rev limiter that is...


btw, there was time to have a long look at the speedo in Fuchsröhre because the streamer at the top of the windscreen effectively blocked ALL view of the track...
Not always a good thing to be tall I guess.

I kind of see glimpses off the similar speeds. The only place I have plenty of time to see the grass grow is going from Bergwerk towards Steilstrecke
But looking at my own excel sheet there is a miscalculation, can't be true that a standard ts just does 182 km/h in 5th at 6500 rpm with 195/50-15's. I first have to do some homework

here you have a handy calculator...

All this info will keep me quiet in my corner for a while. making use of that calculator already.
Jes , I deffinately need wider rubber after to today. I was trying to keep up with the 3.7 Glenwood GTV which also runs 225 15''. The car bulleted past me through one of long sweeps today with significantly more grip and applying 100hp more while i could feel my car just slipping underneath me(on total limit - for me).
There is a TS 75 box in car at moment.

Giuliettaevo2 wrote:here you have a handy calculator...

too simple!

Checked my file, I've got some very exotic non alfa gear ratio in there
I'm altering the file to make it a bit more orderly.

The calculator needs a tyre circumference input to be more accurate. Not all tyres are the same based on the aspect ratio alone.

Close enough

Ok, found myself a nice goal.

This weekend in a German supermarket I stumbled over an test article of the new fiat grande puncto abarth with “esseesse” kit.
Car specs:
1.4-litre turbocharged engine 180 hp @ 5,750 rpm, max torque 272 Nm
http://carscoop.blogspot.com/2007/09/20 ... eesse.html

This particular magazine tests the featured cars sometimes on the nurburgring and always places a nice picture with speeds and G's on the ring. This was street tires (P-zero nero)


So with a serious power disadvantage the best option would be the 1.6 box.
According to my own sheet..


Because of the low budget this year I will open up my spare TS box and see how good/bad it is.
If there is to much up for replacement I go 1.8 without LSD / have to find a low budget way of lsd'ing the 1.8 box.

The spare 1.6 box is kept in store for the time that I can build a real screamer

9:09 Sport Auto is what, 8.49 BTG or something?

Is the rev limiter moved in the Squadra code?