S40 BTCC Nürburgring 2017

[Marius]

 

[wowka]

Schee ; ) Klingt auch ganz gut für ein 4 Zylinder

 

[Marius]

Es ist ein 5-Zyl. Steht auch in der Beschreibung.

 

[wowka]

Ahhh wer lesen kann ist klar im Vorteil : )

 

[Don_Panoz]

Waren die S40 in der BTCC mit den 290PS denn schon leistungsmäßig ausgereizt? Wobei der 5-Zylinder wahrscheinlich von unten raus mit seinem Drehmoment Vorteile haben dürfte.

 

[daniel2345]

145 Ps pro Liter Hubraum renntauglich zu haben war zu der Zeit schon ein respektabler Wert.

Die 8500 U/min sind für den Motor auch recht grenzwertig.
Wir schaffen es auf der Viertelmeile auch nur auf 8800, aber das auf keinen Fall für eine Rundstrecken-Distanz. Lässt man den Motor zu lange so laufen, reißen die Ventilteller am Schaft glatt ab.

Und ohne (dort nicht erlaubte) Aufladung bekommt man die Füllung auch kaum noch rauf.

 

[Don_Panoz]

Die Drehzahlangabe war für mich nun auch etwas überraschend. Aber worauf es mir in erster Linie ging war der Leistungsunterschied zur Konkurrenz. Da gab es doch den einen oder anderen Hersteller, der mit bis zu 20 PS mehr aufwarten konnte. Die Motorcharakteristik und die Fahrbarkeit stehen auf einem anderen Blatt.

 

[Misanthrop]

Hier mal ein guter "Bericht" von Stav-Tech über einen wichtigen Punkt den auch Daniel anspricht.

Another of the wild ways race teams go to extremes to bypass the word of the race regulations is the Volvo BTCC engine in the 90s.

The head, modified in the conventional way the rules "seemed" to allow, produced 260bhp, about 25bhp down on most the cars in the series at the time- Not enough to be competitive.

So TWR, who ran the works team at the time, set to work studying every letter of the rules to find a way around it, and they did, in maybe the most complex way ever!

The BTCC rules basically stated they had to use the production cylinder head. They could port them, they could fit bigger valves, but they couldn't weld extra metal on to in inside the heads, and they couldn't modify the valve angle either.

But it didn't say you couldn't cut stuff off, they didn't say you couldn't add metal by bolting it on, and didn't say what angle the head had to sit on the block.
So they did ALL of that and a lot more!

They pretty much chopped the whole top half of the head off, and bolted on a custom billet setup to house the big valves and cams the rules allowed.
The standard valve angle wasn't ideal either, too steep, but that wasn't allowed to be changed. But as the angle that the head bolted to the block wasn't mentioned in the rules, they cut a wedge out of it, so what was left of the production part was tilted in a way that allowed a shallower exhaust port and steeper inlet port design.

There was enough of the Volvo head left in the middle to still pass the regs as a 'Production' head, but this new 13.5:1 compression engine made 325bhp- 65bhp more than before, and pretty much the most powerful engine in the field.

The legality of it was queried after every race, and every time it was proven to be within the word of the regulations.

The main stupid thing was the production head rules was intended to keep costs of the series down, but instead of allowing a custom head design, which would've been 15k for the original then a few hundred each time to re-produce, they were spending £15k each time chopping up and wildly modifying £200 production heads!

Quelle: https://m.facebook.com/story.php?story_fbid=882994995210357&id=630429603800232