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Discussion Starter #1
I did this comparision one week before I had the Hi-tech exhaust fitted (ie. my car was 100% stock).

Acceleration comparisions:
- test #1: 10 - 150kph, starting in 1st gear both cars:
The HSV pulled away good 2 car lengths straight away (ie. before 60kph). Then the Zed lost good 1 car length in the 1st-to-2nd gear change (the small chirp did not help). I was already well behind, and lost another 1 - 2 car lengths by the time we shut down at 150kph. So I lost by good 5 car lengths.

- test #2: 10 - 160kph, me in 2nd gear and HSV in 1st:
I thought I'd try the same thing in 2nd gear just to get a better understanding of the HSV advantage. I jumped on power a fraction before the HSV and pulled out about 1/3 of the car length. Though, the HSV took only about 2 secs to be ahead of me and pulling away. It pulled about 3 car-lengths. by the end of 2nd and then probably another before 150kph. So the result did not look that different to the one above, but I did buy myself at least one car length with my jump-start.

- test #3: 40 - 150kph, starting in 1st gear both cars:
I figured let's start with a bit higher revs to try and reduce the HSV's low-revs-grunt advantage. We started from 40kph and things were a lot closer. Things were pretty even while I was in 1st gear, but then lost good 1/2+ car length on the 1st-to-2nd gear-change. The HSV was still in 1st gear then and pulled another car-length on me before 80kph (ie. before it shifted to 2nd). Then things stayed reasonably close and the HSV only pulled (at most) another car-length before we shut down at 150kph. So, again the win goes to the HSV by 2.5 - 3 car-lengths.

- test #4: 40 - 160kph, me in 2nd gear and HSV in 1st:
I thought I'd try the same run as before, but starting in 2nd gear. I thought that I would save one gear-change, but then would lose out at the start. To my surprise the HSV did not pull away much before 75kph (ie. while the HSV was in 1st) ... it pulled only about 1 car-length and not having to do the 1st-to-2nd gear-change helped me while the HSV did need that change. After that things stayed very close and the HSV pulled only about 1/2 a car on me before we shut down at 160kph.

Impressions:
My observations are:
- At very low revs, the HSV has big advantage no matter what gear you're in.
- In 1st gear above 30kph, the HSV and Zed are pretty close.
- In 2nd gear (ie. 60 - 100kph) the HSV has an advantage. This was by far the most convincing segment for the HSV and there was nothing I could do in the Zed to keep up.
- In 3rd gear I'd say that things looked closer (still slight advantage to the HSV). The HSV was still in 2nd while the Zed was in 3rd.
- My guess is that above 100kph things should be relatgively close, but bellow that the HSV has a big advantage at the moment.

HSV R8 information/stats:
- 1705kg,
- 260kW/480nM (HSV claim with good fuel),
- sports suspension,
- 18" wheels 235/35 Pirreelli P-Zero Rosso all the way around
- 345mm cross drilled brakes

This R8 in particular is an Auto (4 speed), but that does not matter much 'cos it has oodles of torque. Accordring to local magazines it does 6.0secs for the 0-100km/h time and 14.0 with 166km/h for the 400m run. Manual beats it by only couple 10th or so. The gearing is 75, 140, 230, 330km/h in each gear (will top at about 265km/h).
 

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Discussion Starter #2
And one week later, when I had the Hi-tech exhaust and K&N filter fitted, lined up the two cars again.

Acceleration comparisions:
- test #1: 40 - 150kph, starting in 1st gear both cars:
The two car's stay dead even until I have to make the 1st-to-2nd gear-change (around 60kph), where I loose about 1/2 a car-length. Then the two car's stay dead-even again (ie. no one pulls) 'till around 100kph where I have to make the 2nd-to-3rd gear-change. Here I loose another 1/2 a car-length and the HSV is still in 2nd gear so it pulls away another 1/2 a car-length before it shifts to 3rd at around 135kph. After that things look pretty even to 150kph when we shut down. So the HSV won this one by around 1.5 car-lengths. The HSV has still has advantage over my Zed in the 100 - 130kph range as it is still in 2nd gear while I have to be in 3rd. Though, the advantage is very small now.

- test #2: 50 - 150kph, me in 2nd gear and HSV in 1st:
The first run we did the HSV got a jump on me and therefore it looked like it was steadily, but slowly pulling away all the way to 150kph, by which stage it was around 3 car-lengths ahead. When we run the 2nd time, we took off more evenly, but the HSV was still quicker than me ... but not by much. It pulled away maybe 3/4 car-length on me by the time I shifted to 3rd (ie. 100kph), where I lost maybe 1/4 car as well. It stayed like this all the way to around 150kph where we shut down and I was not pulling the HSV in, nor was it pulling away. I lost this one by 1 car-length.

- test #3: 20 - 165kph, me in 1st gear and HSV in Drive:
As soon as we floor it, the HSV has to down-change (to 1st gear) and I get about 1/2 a car jump on it during this time. I hold this all the way through 1st and don't really loose any ground on the 1st-to-2nd gear-change ... only about a foot or two. Then I pull away another 1/4 to 1/3 car-length before I need to shift to 3rd (ie. 100kph). So the HSV is on my rear-quarter panel and I shift to 3rd, loose very little ground and then we run all the way to 165kph by which time I maybe pulled another 1/2 a car-length. That means that at the end I was around 1 - 1.5 car-lengths ahead and there was no pulling away or gaining from either of us.

Impressions:
I'd say that now the 350Z is about line-ball in terms of acceleration with the HSV. The 350Z looses a little bit of ground on gear-changes (even if you nail them really well), but it is no longer slower in-gear. In some ways it can even pull away a fraction in some increments, but I'd call this pretty **** even, and I'm sure I can out-launch it by 1 - 1.5 car-lengths (mostly due to the weight).

When comparing this to the 350Z with the standard exhaust, I'd say than in the rolling starts I'm good 3 - 4 car-lengths ahead by the time I reach 150kph ... that is around 0.3 - 0.4sec in a 400m run, so I'm pretty impressed. Oh, and I'm no longer slower through the 1st and 2nd (in particular) gears than the HSV.

I'd say that I'm at least as quick as an S2000 in full-flight now, and a lot quicker in low to mid revs. Incredible that 'just an exhaust' can provide this kind of gains. Or even more incredible that Nissan would fit the car with an exhaust that 'strangles' the engine so much?!
 

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Thanks David - I would have thought we'd be a bit closer to the 260Kw clubbie as I have a mate with a 285kw and the margins are about what you described when I run with him.
 

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Discussion Starter #4
Thanks David - I would have thought we'd be a bit closer to the 260Kw clubbie as I have a mate with a 285kw and the margins are about what you described when I run with him.

The 285kW HSV should certainly be quicker than the 260kW one, but keep in mind that the power increases inthe HSVs are mostly just in the last 1000rpm or so. For instance the difference between the 250kW HSV, and a 300kW one is minimal bellow 5500rpm. Though, the 300kW climbs up much more after that, and also gets some extra revs.

What that means is that unless it's reved all the way out, there will be very little differennce between a 250kW and 300kW HSVs. Though, rev it out and watch it pull out about 1/2sec (ie. 5 car lengths) over 400m.

ps. Is your mates HSV manual or auto?
 

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Thanks for that additional infor. His is an Auto, as is my Zed
 

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Discussion Starter #6
As I mentioned in another thread, I strapped Yun's G'tech on both my Zed and the HSV R8. Incredible how close the numbers were, and I'd say that with another few goes I might have shaved off another 10th of those HSV times.

These are the times from the G'tech (350Z vs HSV R8 Auto):

- 0-60kph = 2.79 vs 2.90sec
- 0-100kph = 5.96 vs 6.11sec
- 0-130kph = 8.90 vs 9.23sec

- 0-60mph = 5.46 vs 5.76sec

And now the time to distance data:

- 20m = 2.38 vs 2.36sec (HSV 0.31m ahead, ie. at just over 50kph)
- 100m = 6.02 vs 6.05sec (350Z 0.83m ahead, ie at ~100kph)
- 200m = 9.09 vs 9.19sec (350Z 3.54m ahead, ie. at ~130kph)

This show that the side-by-side comparos can produce reasonably accurate results.
 
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