Real world V6 Performance difference

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Dean
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Real world V6 Performance difference

Post by Dean » Sun Jun 21, 2020 8:27 pm

I have often wondered about the real world performance differences between V6 models, especially the PRV variants, I have seen 3 12v PRV cars put on the dyno and all of them have made more power, sometimes a fair bit more, than the stated 167hp. Is this a result of sympathetic dynamometer’s or an understatement Of power by PSA to make the expensive 24v option look more appealing?
Anyway, I was out for a drive this evening, having a play and since I had the time and space I downloaded an app to time acceleration on my 12v PRV auto and here are the results of three runs on the same stretch of road. Stated 0-60 time For the 12v auto seems to be about 10 sec with the Manual 24v being 7sec and yet
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I would like to try another app and compare but these figures are substantially quicker than stated, has anyone else tested sprint times?

D
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Jaki1122
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Re: Real world V6 Performance difference

Post by Jaki1122 » Mon Jun 22, 2020 2:12 am

Ideally, you want to compare two manual cars or two automatics. I'm sure gear ratios are different between both gearboxes (I haven't checked so correct me if I'm wrong here) and autos weight more than manuals. Also is harder to move the auto than the manual (so less power loss with the manual, which means better performance). Gearshift time is also a variable, but in upshift I wouldn't be surprised if the auto is actually shifting a bit faster than the manual. All of this considering of course that shifts are always done at the right moment which could not be the case.
Resuming, in the performance tests, the auto has some disadvantage, due to weight and power loss. Could have a gearing advantage (again, I don't know the ratios on the autos), but that's about it.

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Re: Real world V6 Performance difference

Post by Dieselman » Mon Jun 22, 2020 5:27 am

Autos gain an advantage in so much as the torque converter acts as a torque multiplier, but are nearly always slower than manuals due to the box needing engine power, to operate.

The 12v manual is only about 0.6s slower to 60mph than the 24v, but the way it delivers it is vastly different.
The 12v gives steady, constant acceleration, whereas the 24v goes well enough, up to 4,500rpm..then it really wakes up.

The 400m dash is the best figure of performance.
I'd be wary of app performance testing, too many variables and assumptions. You really need an accurate measure of distance covered per 100th second.
Your times all appear to be rounded to whole seconds. Is that rounded up, or down?

The app seems to have lost your 400m terminal speed and 0-150kmh times...😉
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Re: Real world V6 Performance difference

Post by citroenxm » Mon Jun 22, 2020 7:05 am

12v prvs in the Xm weren't rated 167bhp anyway dean I'm sure they were 176 bhp with newer efi systems. The prv was 167 bhp in carb form in the Talbot tagora in the 80s were all other or installs at the timer were 156bhp or so.. it had a very low bhp in the 70s and 80s..
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Dean
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Re: Real world V6 Performance difference

Post by Dean » Mon Jun 22, 2020 8:37 am

The 2.7 odd fire was 130hp in the states and 140hp in the Europe, I was sure the later 3.0 evenfire was 167, later down rated with the small cc change to 165 but that is not official Citroen I don’t think.
I wonder if the 24v makes more than 200hp if a 20 year old 12v can dyno at 180hp, allegedly.

D
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