Motor January 2016 - Chrysler 300 SRT v HSV R8

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Originally Posted by Cobra

That 6.4 Hemi is a beast. Surely it's pushing more than 350kw? I love it how it's a bees' dick quicker in every way than the LSA - that's got to upset the apple cart a bit! I know that the HSV runs a six speed tranny versus the eight speed of the SRT, but seriously that 400kw LSA powered wagon is slower than a 335kw R-Spec GT.

Looking closely at the low speed data shows that both cars launched extremely well so I wouldn't be surprised if the cars tanks were about full and with 80 kg drivers, that would bring the Chryslers weight to around 2045 kg (4508 pounds) and the HSV's weight to around 2054 kg's (4528 pounds).
Using the "Wallace Racing ET and MPH in 1/4 Calculator" and putting in the end speeds and weights gave me an estimated 373.77 kW (501.24 HP) for the Chrysler and 376.75 kW (505.23 hp) for the HSV.
I think it's worth keeping in mind that in addition to it's having 2 more gears than the HSV, the Chrysler has a new transmission, so I'd expect it to drag less power than the HSV's transmission which I believe is known as a heavy duty transmission, so perhaps the Chryslers engine might be looking just a little bit too good by comparison.
That said though it seems to be a great motor and a good car.
I should mention that when I used the Calculator, I took 1 k off the Motor end speeds, because Dragstrip end speeds are averaged over the last 66 feet and Motors Racelogic end speed data would have been the speed at 400 metres. At this performance level around 1 k is the correct adjustment to make.
In summary I'm thinking that the HSV may perhaps have been just a bit short of 400 kW and the Chrysler may just have been a bit better than the claimed 355 kW figure.

Interestingly when I calculated my stock untuned XR6 Turbo's power from it's end speed and racing weight, it came out at 335.9 kW, but I had a temperature advantage which would have handed my car a bit over a 1.5% power advantage, so to get a rough idea I'll take off 1.5% and that would bring my car to 330.86 kW at the flywheel.

Of course that's way above the claimed 270 kW, but as my GPS test gear has shown, the car gets a 10% acceleration boost from 98 fuel compared to 91, so as I was using the premium fuel I suspect it was getting somewhere around 10% more power and as Dyno tests have indicated, the overboost appears to be worth 10 to 12%.
So if I add 10% to 270 and then add a further 11%, I get 329.67 kW which is just over 1 kW short of the above 330.86 kW figure and my Dyno sheets point to it having close to 330 kw at the flywheel.
A bit off topic I know, but I suspect still of interest to quite a few forum members.

As a final point, a former FPV employee who should definitely know, has told me that the F6 also has an overboost feature that is worth around 10% above it's 310 kW figure so that would put it at 341 kW and I suspect that might be a conservative figure. Note though that it's 310 figure was obtained on 98 fuel).