A question a few people have asked me before
£8k for the x51 upgrade commonly known as the powerkit option, was it worth it. Especially given the other mods available.
It's been a hard one to answer and not always clear even if you back to back the standard engined car with mine as the ones I have driven have always been heavily modified and both have quite distinct characters.
Then came my 40k service at Porscheshop.
A number of changes were planned that meant by default the cars would be near identical to Porscheshop's new 997 demonstrator except for the engine itself (& of course remap potential)
Part of the plan was then to send the car to Viezu locally to have a live rolling road re-map to optimize the car for road driving and get the final 2-3% of "performance" as always the objective was to optimize for drive ability not absolute power.
Ian from Porscheshop then suggested his new demo car needed the same - both cars were identical bar the engine, same exhaust, intake, flywheel & clutch, same upgraded suspension (so losses on the rolling road would be similar), same basic remap - both for drive ability not for top end power. So at last we could compare like with like on the same rolling road back to back.
So what did we find?
The results were interesting to say the least - initially it seemed maybe not money well spent. At peak power the x51 was only a little over 10whp (wheel horse power) up on the standard engine. So £800 per whp -ouch!
BUT - then we looked at the torque, it was about 30lbft higher at peak & averaged over 20lbft higher across the whole rev range (at the wheels, including a gap under 2k revs where the single mass flywheel leaves you short of torque)
That had me thinking then surely there must be a bigger power difference - so I looked more carefully at the graphs and the truth was obvious - the x51 is a much "better" engine.
At all bar peak power and a few hundred revs either side the x51 was running at least 30 wheel HP more. 30-40 lb foot more torque between 3k revs and 7k revs. For power the difference was all the way through the rev range. When you convert that back to numbers at the engine this is a big difference.
The x51 has a much bigger and wider torque curve and consequentially a much wider power band. From 2.5 to 6k revs it much higher torque and power it just murders the standard engine. Also post remapping it had a much smoother torque and power curve with far less dips and local peaks giving much more consistent and elastic performance
So what does that mean?
Simply put the engines responses are very elastic and far more linear than the standard engine - it had masses more torque from low revs - all the way through past peak to the drop off before the red line, so in gear the car pulls harder every gear every rev range. Because it is more linear it is harder to spot from the divers seat as it pulls harder and harder through the revs. So the engine is very deceptive in how it picks up speed on the road
Only briefly near the peak power does the standard engine get near the x51 the res of the rev range its just at a different level.
The number I have given are measured at the wheel, not calculated numbers for the estimated engine but before losses. So the theoretical gap is larger. Over the rev range the average power of the x51 is approx 35whp higher.
The key difference is that the upgraded engine does more work all the way through the rev range rather than at a narrower peak. The price for this is that at peak its not that much more in terms of power than the standard engine.
On the road this should result in significantly better in gear acceleration times across the rev range ie a more flexible engine in some ways not too dissimilar to the GT3 engine but with a lower rev limit and way more torque.
The last measure is that I have driven the Porscheshop car down some familiar roads and followed up a week later with the beast. One was clearly quicker in terms of acceleration in gear and through the gears.
Conclusion
So is it a better engine? Oh yes
Was it worth £8k more?
What do you think?
£8k for the x51 upgrade commonly known as the powerkit option, was it worth it. Especially given the other mods available.
It's been a hard one to answer and not always clear even if you back to back the standard engined car with mine as the ones I have driven have always been heavily modified and both have quite distinct characters.
Then came my 40k service at Porscheshop.
A number of changes were planned that meant by default the cars would be near identical to Porscheshop's new 997 demonstrator except for the engine itself (& of course remap potential)
Part of the plan was then to send the car to Viezu locally to have a live rolling road re-map to optimize the car for road driving and get the final 2-3% of "performance" as always the objective was to optimize for drive ability not absolute power.
Ian from Porscheshop then suggested his new demo car needed the same - both cars were identical bar the engine, same exhaust, intake, flywheel & clutch, same upgraded suspension (so losses on the rolling road would be similar), same basic remap - both for drive ability not for top end power. So at last we could compare like with like on the same rolling road back to back.
So what did we find?
The results were interesting to say the least - initially it seemed maybe not money well spent. At peak power the x51 was only a little over 10whp (wheel horse power) up on the standard engine. So £800 per whp -ouch!
BUT - then we looked at the torque, it was about 30lbft higher at peak & averaged over 20lbft higher across the whole rev range (at the wheels, including a gap under 2k revs where the single mass flywheel leaves you short of torque)
That had me thinking then surely there must be a bigger power difference - so I looked more carefully at the graphs and the truth was obvious - the x51 is a much "better" engine.
At all bar peak power and a few hundred revs either side the x51 was running at least 30 wheel HP more. 30-40 lb foot more torque between 3k revs and 7k revs. For power the difference was all the way through the rev range. When you convert that back to numbers at the engine this is a big difference.
The x51 has a much bigger and wider torque curve and consequentially a much wider power band. From 2.5 to 6k revs it much higher torque and power it just murders the standard engine. Also post remapping it had a much smoother torque and power curve with far less dips and local peaks giving much more consistent and elastic performance
So what does that mean?
Simply put the engines responses are very elastic and far more linear than the standard engine - it had masses more torque from low revs - all the way through past peak to the drop off before the red line, so in gear the car pulls harder every gear every rev range. Because it is more linear it is harder to spot from the divers seat as it pulls harder and harder through the revs. So the engine is very deceptive in how it picks up speed on the road
Only briefly near the peak power does the standard engine get near the x51 the res of the rev range its just at a different level.
The number I have given are measured at the wheel, not calculated numbers for the estimated engine but before losses. So the theoretical gap is larger. Over the rev range the average power of the x51 is approx 35whp higher.
The key difference is that the upgraded engine does more work all the way through the rev range rather than at a narrower peak. The price for this is that at peak its not that much more in terms of power than the standard engine.
On the road this should result in significantly better in gear acceleration times across the rev range ie a more flexible engine in some ways not too dissimilar to the GT3 engine but with a lower rev limit and way more torque.
The last measure is that I have driven the Porscheshop car down some familiar roads and followed up a week later with the beast. One was clearly quicker in terms of acceleration in gear and through the gears.
Conclusion
So is it a better engine? Oh yes
Was it worth £8k more?
What do you think?
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