S2000 technical thread

**OldF** · 2nd Jul 08, 13:29

I opened a new thread because my question is off topic. The original thread was: “Ypres Westhoek Rally 2008”.

Mirek Fric [Cze] wrote:

Josti: You're not right completely. They missed top speed agains Peugeots only. Fiats go on short gearbox practicaly everywhere. It is because weak engine of Fiat (which is weaker than VW, that was confirmed by Loix and Czopik last year). Even last year in Finland Alén was going on short gearbox with a top speed of 168 km/h!

Compared to that Peugeots usualy uses medium gearbox. We compared that also on rally Hustopeče in Czech champ. where there Béreš's Fiat was evidently weaker than Kopecký's Peugeot (even by sight). From GPS top speed we know that Kopecký was on medium and Béreš on short gearbox. Even though Peugeot was much beter in slow corners and handbrake turns.

Mirek, as far as I know it’s not possible to make handbrake turns if the centre differential has a mechanical lock. When the rules changed few years ago for the WRC cars, one argument for retaining the active centre differential was the ability to make handbrake turns. So, my question is: Do you know if the S2000 cars are using the mechanical lock in the centre differential?

**Mirek** · 2nd Jul 08, 15:20

All S2000 cars have mechanical central diffenrential but I think the handbrake release must be possible by some kind of clutch or any other way. Anyway S2000 cars can do handbrake turn and they do it.

I was also told that 207 doesn't have central differential at all. It seems to be strange to me as I remeber only some gr.B cars without it (Quattro A2 for example) but they also didn't use handbrake. I'll try to ask about 207, how is it actualy.

**HaCo** · 2nd Jul 08, 16:03

I'm not absolutely sure, but I thought that the VW only recieved a handbrake on the end of last year. GTA will defenatly know more about it.

Funny to mention I think: Voullioz didn't want to use his handbrake any more in Ypres on the second day. Everything time he used something went wrong (he also was in a ditch for a minute during day 1).

There is something about direct injection mentioned on the Skoda thread. Is it allowed or not, what advantage could it bring? Anyone?

**Mirek** · 2nd Jul 08, 16:13

Dirrect injection is allowed if used on production base engine.

**oreixa** · 2nd Jul 08, 16:53

Originally Posted by HaCo

I'm not absolutely sure, but I thought that the VW only recieved a handbrake on the end of last year.

Yes, you are right.

**dimviii** · 2nd Jul 08, 17:38

just my 2 cents...
in my evo viii according to manual,you can use the handbrake without problems with the centre diff.
same for evo 9.
evolutions have mechanical centre differentials.
they have an switch under the handbrake lever,and as you use the handbrake a signal goes to the centre diff ecu and releases the centre diff via a electrohydraulic clutch.

**OldF** · 2nd Jul 08, 18:43

the centre diff ecu and releases the centre diff via a electrohydraulic clutch.

The locking mechanism (the clutch discs) is mechanical but it’s controlled by the ECU. Evo 9 has a same type of central differential than the WRC cars. A purely mechanical limited slip differential is also “controlled” mechanically. Here are a couple good sites that explain how they work.

http://www.gordon-glasgow.org/lsdtech.html

http://icpcitation.com/variloc_theory.htm

**OldF** · 2nd Jul 08, 19:30

Originally Posted by HaCo

There is something about direct injection mentioned on the Skoda thread. Is it allowed or not, what advantage could it bring? Anyone?

Higher power and cmpression ratio, better fuel efficiency, peak torque on lower revs etc.

http://en.wikipedia.org/wiki/Gasoline_direct_injection

http://www.mitsubishi-motors.com/cor...ent/e/gdi.html

I found an article from a Finnish motor magazine from 1997 about the Mitsubishi Carisma 1,8 GDI. The GDI had it’s peak torque (174 Nm) @ 3750 rpm compared for the MPI that had the peak torque @ 4500 rpm.

I compared a 2-litre Audi with MPI and GDI

MPI: compression ratio 10,3:1; 131 hp @ 5700 rpm; 195 Nm @ 3300 rpm
GDI: compression ratio 11,5:1; 150 hp @ 6000 rpm; 200 Nm @ 3500 rpm

RS · 2nd Jul 08, 19:54

Originally Posted by OldF

Higher power and cmpression ratio, better fuel efficiency, peak torque on lower revs etc.

http://en.wikipedia.org/wiki/Gasoline_direct_injection

http://www.mitsubishi-motors.com/cor...ent/e/gdi.html

I found an article from a Finnish motor magazine from 1997 about the Mitsubishi Carisma 1,8 GDI. The GDI had it’s peak torque (174 Nm) @ 3750 rpm compared for the MPI that had the peak torque @ 4500 rpm.

I compared a 2-litre Audi with MPI and GDI

MPI: compression ratio 10,3:1; 131 hp @ 5700 rpm; 195 Nm @ 3300 rpm
GDI: compression ratio 11,5:1; 150 hp @ 6000 rpm; 200 Nm @ 3500 rpm

The latter of those two engines is the base unit Skoda are using in the Fabia.

**wwbroe** · 2nd Jul 08, 21:19

Originally Posted by HaCo

I'm not absolutely sure, but I thought that the VW only recieved a handbrake on the end of last year. GTA will defenatly know more about it.

Funny to mention I think: Voullioz didn't want to use his handbrake any more in Ypres on the second day. Everything time he used something went wrong (he also was in a ditch for a minute during day 1).

Haco, not that it is that important, but Voullioz wasn't in a ditch on day 1 but on day two at Watou stage. He could use handbrake, but as a matter of fact he didn't want to use it any more at end of day 2, because of two spins using the handbrake. (but i think we are off-topic).
Concerning the Polo, they had handbrake all the time, but couldn't use it to make turns. It was indeed only at the end of last year's season that the handbrake could be used to take hairpins for example. But Loix had the same problems with handbrake with the Punto that he used in IRC last year. It was only the Pug that didn't have any problems using the handbrake.

**HaCo** · 3rd Jul 08, 16:20

Yep wwbroe, you're right it was day 2.

**Tazz** · 4th Jul 08, 07:10

The Sadev rear diff has a hydraulic clutch that should release when the handbrake is used for turns. I know there were some issues with the pressure it needed to release being quite high. That meant that it didnt always fully release on pressure from the handbrake hydraulic system.

**Mirek** · 6th Jul 08, 15:51

Tazz: Thanks.

So, here it is. Peugeot 207 S2000 doesn't have central differential. Confirmed.

**OldF** · 13th Jul 08, 13:46

Originally Posted by Tazz

The Sadev rear diff has a hydraulic clutch that should release when the handbrake is used for turns. I know there were some issues with the pressure it needed to release being quite high. That meant that it didnt always fully release on pressure from the handbrake hydraulic system.

Thank you Tazz for the information.

This means that Pug S2000 is an all time 4WD car like the group B cars. Maybe it doesn't affect the drivability that much and they prefere to have a system that enables handbrake turns.

Isn't Abarth also using Sadev? So the Abarth and all others using the Sadev should have the same clutch?

There is a lot of torque going true the clutch so I think the problem with relesing the clutch is that it need a high hydraulic pressure to relese the clutch.

RS · 13th Jul 08, 19:33

Originally Posted by OldF

Thank you Tazz for the information.

This means that Pug S2000 is an all time 4WD car like the group B cars. Maybe it doesn't affect the drivability that much and they prefere to have a system that enables handbrake turns.

I suppose not having the centre diff also saves them some weight and saps less power.

**Sulland** · 21st Jul 08, 00:03

The 207 seems to be the quickest in 08 as well. What areas does the Abarth need to strengthen to catch up ?

Are there areas the where the Abarth is better than the 207 ?

**Mirek** · 21st Jul 08, 01:31

They would need to have at least beter engine and reliability...

**HaCo** · 21st Jul 08, 08:41

Yesterday I saw the MotorsTV coverage of rally Russia. The Pugs had a lot more punctures in Russia apparently due to wheels that were strong enough for the Russian conditions.

**OldF** · 22nd Jul 08, 18:22

Originally Posted by Sulland

The 207 seems to be the quickest in 08 as well. What areas does the Abarth need to strengthen to catch up ?

Are there areas the where the Abarth is better than the 207 ?

There was an interview of Anton Alén in the Finnish motor sport magazine “Vauhdin Maailma” (07/2008) where Anton told that he yearn for more torque and broader rev band. Further he says that the revs shouldn’t drop below 7000 rpm because below 7000 rpm the engine is very lazy.

By the S2000 database the Pug has 250 Nm @ 6500 rpm and 280 hp @ 8250 rpm (http://www.s2000rally.com/peugeot-207-s2000.php). Grande Punto has 250 Nm @ 7000 rpm and 275 hp @ 8250 rpm (http://www.s2000rally.com/abarth-punto-s2000.php). By the Abarth’s web site the Punto has 225 Nm @ 6500 rpm and 270 hp @ 8250 (http://www.abarth.it/?lan=eng&skipintro=1 / Racing -> Abarth models in the race).

Whatever the correct figures are for the Punto, Pug has a broader rev band and the peak torque on lower revs compared to the Punto, or has higher torque at 6500 rpm.

**Mirek** · 22nd Jul 08, 18:40

Don't get that numbers too serious. Those on database are partly my work...

225 Nm can't be engine torque. It must be on wheels since such engine would have less than 270 Hp. In fact private Puntos had about 260-270 Hp in last season.

But the torque difference between 207 and Punto is obvious. The more because Pugs are usualy going on medium gearbox on stages like we have. Fiats on short.