Frankshaft wrote: ↑
Sun Sep 16, 2018 12:29 pm
Frankshaft wrote: ↑
Sun Sep 16, 2018 11:34 am
GARY C wrote: ↑
Sun Sep 16, 2018 1:36 am
On a well developed engine you will have good ft/lb per cube numbers even if the engine operates well about peak tq, the better the average is a above peak then the better the shift recovery will be.
Trans and rear ends or a balance between weight, efficiency and ratio to keep it in the rpm range needed not to mention cost, most fast power adder drag cars make to much tq so more gear or gears do not help, prostock on the other hand are running 6 speeds now I believe and would run 7 if possible but they are operating well above peak and trying to target about a 1500 rpm curve so the engine doesn't bog.
The pro turbo diesel cars run more gears to keep the rpm down, maybe Linco's?
In most classes that allow turbo diesel there are competitive examples as well as dominant ones, in the Daytona 24 hour Proto Type Class I think it was Audi that dominated it a cpl years with one that was only turning around 4700 rpm if I recall, since then others have tryed.
There are not a lot of people in the industry with the knowledge or pocket book to pursue it.
Nice post. I will say though, the fastest accelerating diesel door slammer, that runs either low 7's or may have squeaked a 6.9 something, with a Duramax, spins up there, 7000 ish. The Daytona 24 example, what a great idea though, keep rpm to 4700, the thing would go for 3 weeks straight probably. That deal its about consistent and steady. Not being the fastest.
I just looked, the Audi R10 tdi is a 336 inch v12. It makes 650hp at 5000. So, I would imagine they were likely seeing 6000 ish on the long straights. 2000 pounds ready to race with driver.
Drive train durability seems to be the hurdle for turbo diesel but considering the small amount of race R&D in the last ten years only time will tell if they find the magic combo but the two diesel cars were the fastest, I haven't followed any of it to know where they are now.
In 2004, a Lola equipped with a Caterpillar re-badged V10 TDI ran for a few hours before breaking its clutch.
On 18 March 2006, the #2 Audi R10 won the 54th annual 12 Hours of Sebring after earning pole position by setting a qualifying record.
On 18 June 2006, the #8 Audi R10 placed first at the 2006 24 Hours of Le Mans, completing 380 laps, more than the R8 did, but less than the record set in 1971. The #7 Audi R10, which set fastest lap times in practice and race, came in third after suffering injector pump damage, completing 367 laps.
Here is the Audi info. https://en.wikipedia.org/wiki/Audi_R10_TDI
In car vid it looks like shifts are in the 6000's https://www.youtube.com/watch?v=WVIqAuymkU0
On the 3rd of June 2007, Peugeot managed to best the Audi R10 TDI diesel, setting a Le Mans test day lap time of 3:26.707. This was followed by Peugeot earning pole position in Le Mans qualifying with a 3:26.344 set by Stéphane Sarrazin, again beating Audi - although it is believed Audi did not go as fast as they could, unlike Peugeot. In the race, where the cars competed directly for the first time, the Audi R10s were obviously faster than the Peugeots on the straights and much more stable in the corners
Here is the Peugeot 908 HDi FAP https://en.wikipedia.org/wiki/Peugeot_908_HDi_FAP
In car https://www.youtube.com/watch?v=WO6tRAigC3M