S2000 technical thread

[OldF]

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]

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]

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]

Dirrect injection is allowed if used on production base engine.

[oreixa]

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]

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]

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]

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/corporate/about_us/technology/environment/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]

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/corporate/about_us/technology/environment/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]

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]

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

[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.

[Mirek]

Tazz: Thanks.

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

[OldF]

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]

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]

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]

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

[HaCo]

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]

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]

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

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.

[OldF]

Yes, it’s very difficult to find accurate figures for power and torque. The only way to find out how the Pug and Punto compares would be to put them in the SAME dyno.

It seems that the torque should be higher because if the power is 270 hp @ 8250 rpm, the torque is 229,8 Nm (270 / (8250 * 0,0001424 = 229,8 Nm). 260 hp would give a torque of 221,3 Nm. Maybe the 225 Nm torque is the torque at peak power and the peak torque is always on lower revs than peak power.

As Anton told in the interview the Punto’s engine is very lazy below 7000 rpm, which would indicate that the torque peak is around 7000 rpm.

Bump! thx !

[Sulland]

Is the Abarth S2000 on par with the newer S2000 cars on tarmac, and how much is it behind pr km on gravel ?

Just to better understand the development of the S2000 class since 2006.

[Barreis]

Only Abarth knows difference between works and customer cars..

[OldF]

It would be nice if some motorsport magazine would do a comparison test between the S2000 cars.

[Barreis]

In Italian magazines (Tutto rally, Rally sprint) there're plenty of it..

[Sulland]

In Italian magazines (Tutto rally, Rally sprint) there're plenty of it..

Are they online ?

[Barreis]

Unforunatly not.. Great magazines.. Maybe somewhere is pdf , guys from Italy please help us!

[Sulland]

Who of the current manufacturers of S2000 cars will do a last homologation upgrade before 31.12 2010 ?

[OldF]

Who of the current manufacturers of S2000 cars will do a last homologation upgrade before 31.12 2010 ?

I think they can still do homologation upgrades (VO, option variants etc.) after 31.12.2010 but completely new S2000 with 2000 cm3 (KSR / VK-super 2000 rallyes) engines are not possible.

[OldF]

I forgot to mention that Malcom said in an interview (I don’t remember where) that they’ve found some good things concerning the suspension when testing the Fiesta WRC that they’ve would also will apply to the S2000 Fiesta. He didn’t reveal what it was until they’ve homologate the changes at the end of this year.

[Sulland]

Are gear ratios free free in S2000, and has the XTrac box ratioes that allow the S2000s to topspeed over 170 ?

[Mirek]

They are free but must be homologated by manufacturer. Yes, it is possible to have higher top speed. Škoda used longer gears for Ypres and some gravel events (also PG in Sweden last year). Top speed of that setup is 184 km/h I think.

[Juha_Koo]

About safety features... This season the side impact "foam" has become mandatory for (all) S2000s, right? But is there any (or has it changed) rule about the gap between the seats and rollcage? WRCs had that "200 mm rule" which was pretty visible to the eyes, especially in the Focus.

Going bit offtopic, but has the 200mm rule now been overruled with new WRC cars due to their smaller size? Atleast the minimum diameter of rollcage tubing was changed to a bigger one.

[adr17]

all s2000 with xtrac gearboxes ie fiesta , fabia and proton dont have a centre diff they all have a clutch pack in the rear diff which is operated by the handbrake , basically there are two master cylinders on the handbrake when pulled one cylinder sends pressure to the brake calipers and the other to the realease on the rear diff clutch pack , if you didnt have the clutch pack or it didnt work properly when applying the handbrake it would lock all four wheels as there is no centre diff

only allowed one set of gear ratios but two sets of drop gears , which alter your top speed for instance on the fiesta s2000 the top speed is about 108-110 mph which is the common drop gears , the other ratios giving a higher top speed was tested on ypres test but didnt go for it , it works out that to get the benifit of the taller drop gears you would have to be on the limiter for 16 secs on the standard spec as with the taller ones you lose out on acceleration

[adr17]

oh and the same transmission is being used in the wrc fiesta as the s2000 , so no centre diff

[Mirek]

only allowed one set of gear ratios but two sets of drop gears , which alter your top speed for instance on the fiesta s2000 the top speed is about 108-110 mph which is the common drop gears , the other ratios giving a higher top speed was tested on ypres test but didnt go for it , it works out that to get the benifit of the taller drop gears you would have to be on the limiter for 16 secs on the standard spec as with the taller ones you lose out on acceleration

Thanks for interesting details about Fiesta. I think that with Fabia it's rather different as the engine has different characteristics and also the gearing is different with longer 1-2-3 and closer 4-5-6. Anyway Ypres or Sweden proved that it works in Fabia.

[Sulland]

all s2000 with xtrac gearboxes ie fiesta , fabia and proton dont have a centre diff they all have a clutch pack in the rear diff which is operated by the handbrake , basically there are two master cylinders on the handbrake when pulled one cylinder sends pressure to the brake calipers and the other to the realease on the rear diff clutch pack , if you didnt have the clutch pack or it didnt work properly when applying the handbrake it would lock all four wheels as there is no centre diff

only allowed one set of gear ratios but two sets of drop gears , which alter your top speed for instance on the fiesta s2000 the top speed is about 108-110 mph which is the common drop gears , the other ratios giving a higher top speed was tested on ypres test but didnt go for it , it works out that to get the benifit of the taller drop gears you would have to be on the limiter for 16 secs on the standard spec as with the taller ones you lose out on acceleration

So if the Sadev box does not have this feature, can they put in a high 6th, just to get the top speed, even if the 5 to 6 shift drop the engine rpm more than normal ?

[noel157]

The Sadev transmission, instead of master cylinders, has a motor driven disengagement device that allows the handbrake to be applied to the rear wheels only.

[Sulland]

Why is the Skoda so much better than the rest these days?

What are the main areas it is best?

[dimviii]

Why is the Skoda so much better than the rest these days?

What are the main areas it is best?

suspension
factory entry
drivers.

[Jacek]

Hello, I wanted to ask you where is it mentioned that S2000/WRC/R5 can't use center differential? Since when S2000 doesn't use center diff?
I was looking at FIA site and found this regulations:
fia.com/sites/default/files/regulation/file/255A%20%2813-14%29_08.03.2013.pdf - Article 255A – 2013, Specific Regulations for Super 2000 (Rallies) / WRC
this part even mentions central diff but without any specific information

Front/central/rear differentials Only the housings and mechanical limited slip differentials
homologated in the Super 2000 Rally extension may be used (without any modification).
fia.com/sites/default/files/regulation/file/261%20%2813-14%29_08.03.2013.pdf - ARTICLE 261 - 2013, SPECIFIC REGULATIONS FOR CARS IN GROUP R5
This parts mentions only front and rear. Nothing mentioned about center diff -> center diff is forbidden, it works like this ?

605-d0 Differential (front and rear)
The mechanical type limited slip differential must be homologated in VR5.
Does anyone know how this 4WD with just 2 diff works? How is power transferred to rear differential?
For example in productions cars with transverse engine and Haldex coupling (or other like All4 in Mini, or 4Matic in Mercedes A or CLA), power is transmitted directly from transmission to
front wheels: normally through front diff
rear wheels: through angle gear or spur gear to the rear coupling and diff, is it similiar in here ? (picture in attachment)
original picture: bimmertoday.de/wp-content/uploads/MINI-All4-Funktionsweise-02-655x491.jpg
ps. this is my first post here, great forum, tons of interesting information :)

[Mirek]

There are also homologation regulations which are not available for public on FIA website and I guess it's written there (for example specific regulations say that part A may be be homologated but it doesn't say conditions for it, those are in homologation regulations). I have them but only from 2007 when central differential was allowed and used by some teams. Or maybe it's not forbidden to use but no teams actually do...

Anyway I believe the main reason why it was abandoned was that it consumes power but being a mechanical plated type it doesn't bring enough advantage to the handling. For relatively underpowered S2000 it was vital to save every Hp. Also the gearbox without central differential is some 10 kg lighter. In those days the weight limit was lower and no team was able to reach it (in Barum rally 2007 all S2000 cars were 20-30 kg over limit).

First cars Toyota Corolla, Abarth Punto and VW Polo used central differential (homologated 2006). Peugeot was first to choose different (already the first homologation in 2007 was without it). Škoda tested both solutions and decided to take Peugeot way however with different supplier - X-Trac instead of Sadev. Abarth later abandoned the central differential too and also changed supplier to X-Trac. All later cars use only two.

Here X-Trac 633 from Fiesta S2000 specification sheet: http://www.xtrac.com/download.php?type=EVENTFILE&id=73
http://www.xtrac.com/download.php?type=PRODUCTIMAGELARGE1&id=73

[br21]

I think in case of S2000 NA cars mechanical center diff is allowed, but currently nobody uses it. It's not worth using, as Mirek said - gives not enough advantages and some disadvantages - consumes power, weights some kgs and may become faulty.
So they use this special clutch in rear diff to disconnect it when handbrake is used.

I don't know how it exactly is homologated in R5, but it's possible that center diff is not allowed, as FIA saw nobody is using it and it surely adds cost.
Interesting is also that M-Sport uses Sadev in R5 instead of Xtrac, but it's subject for another topic :) .

[Jacek]

Thanks for the answer. I saw info on XTrac site, for 532 SUPER 2000 RALLY GEARBOX:

OPTIONS SUMMARY
..................
Centre differential (Regulations permitting)
So it might be present in older solution/gearbox, but not in the new one.

[Mirek]

Interesting is also that M-Sport uses Sadev in R5 instead of Xtrac, but it's subject for another topic :) .

Maybe Sadev is the only allowed supplier for R5? At the beginning of S2000 regulations it was also only Sadev...


Thanks for the answer. I saw info on XTrac site, for 532 SUPER 2000 RALLY GEARBOX:

So it might be present in older solution/gearbox, but not in the new one.

Yes, older 532 was used in Fabia S2000 at the beginning. I don't know if they later switched to 633 or not.

[br21]

Maybe Sadev is the only allowed supplier for R5? At the beginning of S2000 regulations it was also only Sadev...

Could be. Also I think Sadev might be cheaper than Xtrac.