Litchfield Type 20 (AST's) vs STi PPP Science and Subjectivity!
07 March 2006 | 09:43 AM
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Litchfield Type 20 (AST's) vs STi PPP Science and Subjectivity!
While this might seem like a general technical thread there is a good reason why I have put it in the Suspension section – as you will see….especially with a few days of the AST group buy left…
After 4 months and 4000 miles as a Type 20 owner I thought I would post up my findings (following on from my initial write up here http://bbs.scoobynet.co.uk/showthread.php?t=465458) about the difference the modifications make. First the science and then the subjectivity. And if you just want to know the answer it’s not the extra power that makes the difference….
The Science:
What real measurable difference does the T20 kit add over PPP? And just how does a ‘normal car’ compare? I have recorded the difference the upgrades make across 3 different scenarios. The T20 kit is made up of the T25 handling pack (a fully tricked up suspension kit from the ‘best Impreza on Planet Earth – Autocar’ http://www.powerstation.org.uk/) and the T20 engine upgrade (remap, exhaust and panel filter, 330bhp).
The headline facts –
The T20 is – (against average times achieved in a standard STI PPP)
● 15-20 seconds faster across a 7 mile challenging mountain road
● 5-8 mph faster through a fast sweeping corner
● 3 minutes faster, on average, over a 100 mile cross country route
Now put that in perspective with a ‘normal’ car, in this case a 160bhp TDi Seat Ibiza Cupra (same driver, roads, averaged over a number of journeys etc):
The T20 is:
● 50-65 seconds faster over the 7 miles of mountain road
● 12-15 mph faster through a fast sweeping corner
● and a full 9 minutes faster, on average, over the 100 cross country miles
A bit more detail about the tests….
The mountain road – 7 miles of superb twisting and undulating tarmac using advanced driving techniques to travel quickly and safely within the limits of the road. 15(wet)-20(dry) seconds depending on weather conditions over the standard car.
Favourite fast sweeping corner – a fast sweeping corner on the mountain road, safe-cornering speeds are increased by 5(wet) – 8(dry) mph.
The 100 mile cross country run – a string of challenging A & B roads with every type of driving challenge included, poor road surfaces. The total journey time in the T20 is reduced on average by 3 minutes, which is about right given the 20 seconds gained over 7 miles. This run has to take into account traffic etc so is very much an average time yet the 3 minute reduction is almost constant regardless of weather (though the actual total time is far greater in the wet).
So what makes the T20 faster?
Lets break this down a little further and look at the STi PPP with T25 handling kit vs the full Type 20 (additional remap, exhaust, panel filter)
Perhaps the most startling find was that it’s not the extra power, my STI PPP ran around 290 bhp (hmm where did the other 11bhp go Subaru?) and the T20 a confirmed 330bhp, yet this actually made very little difference to these times. How do I know this you might well ask– because I had the T25 handling kit fitted first and that made all the difference in times. While the T20 remap, exhaust and filter add massively to the whole Scooby experience (oops we're into subjectivity) you can’t measure on a stopwatch the difference this actually makes on the road…So it seems a STi PPP with the T25 handling pack would match a full T20 car, surprising…
Using the Ibiza Cupra to add some reality showed just how good the STi PPP and T20 really are. In all reality the Ibiza was over a minute slower across 7 mile mountain, a good 12 mph slower through the sweeping bend (over hard suspension) and on average 9 minutes slower over the 100 mile trip. With the ESP switched on the Ibiza was much slower again – a way over aggressive system!
The Subjectivity
Power Upgrade. So you might think I would be disappointed that the £1600 cost of the T20 engine upgrades didn’t make such a big difference as the T25 handling kit. Not at all!! There are just so many things you can’t measure on a stopwatch. The pack just adds so much to the whole Scooby experience, the car is more driveable, it sounds fantastic, throttle response is much better and the car runs more smoothly. Where the STi PPP became breathless the T20 is strong and seems to offer even more. In a straight line or around a track (and the T20 has serious ability harass some very exotic machinery but that’s another story for another time!) the difference would probably be clearer but as far as this experiment goes the difference is purely subjective.
Handling Pack. So the real revelation is the T25 handling pack. Although the impact of the kit over standard suspension can easily be measured (15 seconds over 7 mile mountain, 5-8mph sweeping bend, and on average 3 minutes over 100 miles) there is so much more to the story. Car and driver feel totally connected, the feedback through the wheel is transformed every movement of the car can be felt and reacted to instantly. Under braking the car is totally stable and the trademark Impreza ‘wash-out understeer’ is gone - replaced by a superb neutral handling car. When the now mountainous levels of grip (up from massive as standard!) are finally exceeded the car settles into an easy 4 wheel drift which is simple to recover – get it pointing straight - then either apply more power (if the road allows) or brake and turn in again, simple, safe, effective. On standard suspension the PPP was often nervous and uncomfortable and there was always that damn noise from the rear suspension – all cured with this pack. On long journeys with the AST’s set soft the ride is actually more comfortable.
The Outcome
The T20 is the car the STi PPP should be from standard, of that there is no question. If you want to truly feel one with your car and go faster more safely add the T25 handling kit. If you have a standard STi get the T20 pack rather than PPP. If you have a STi PPP adding the T20 pack will just make ownership even more fun, because life is about much more than the numbers on a stopwatch!!
After 4 months and 4000 miles as a Type 20 owner I thought I would post up my findings (following on from my initial write up here http://bbs.scoobynet.co.uk/showthread.php?t=465458) about the difference the modifications make. First the science and then the subjectivity. And if you just want to know the answer it’s not the extra power that makes the difference….
The Science:
What real measurable difference does the T20 kit add over PPP? And just how does a ‘normal car’ compare? I have recorded the difference the upgrades make across 3 different scenarios. The T20 kit is made up of the T25 handling pack (a fully tricked up suspension kit from the ‘best Impreza on Planet Earth – Autocar’ http://www.powerstation.org.uk/) and the T20 engine upgrade (remap, exhaust and panel filter, 330bhp).
The headline facts –
The T20 is – (against average times achieved in a standard STI PPP)
● 15-20 seconds faster across a 7 mile challenging mountain road
● 5-8 mph faster through a fast sweeping corner
● 3 minutes faster, on average, over a 100 mile cross country route
Now put that in perspective with a ‘normal’ car, in this case a 160bhp TDi Seat Ibiza Cupra (same driver, roads, averaged over a number of journeys etc):
The T20 is:
● 50-65 seconds faster over the 7 miles of mountain road
● 12-15 mph faster through a fast sweeping corner
● and a full 9 minutes faster, on average, over the 100 cross country miles
A bit more detail about the tests….
The mountain road – 7 miles of superb twisting and undulating tarmac using advanced driving techniques to travel quickly and safely within the limits of the road. 15(wet)-20(dry) seconds depending on weather conditions over the standard car.
Favourite fast sweeping corner – a fast sweeping corner on the mountain road, safe-cornering speeds are increased by 5(wet) – 8(dry) mph.
The 100 mile cross country run – a string of challenging A & B roads with every type of driving challenge included, poor road surfaces. The total journey time in the T20 is reduced on average by 3 minutes, which is about right given the 20 seconds gained over 7 miles. This run has to take into account traffic etc so is very much an average time yet the 3 minute reduction is almost constant regardless of weather (though the actual total time is far greater in the wet).
So what makes the T20 faster?
Lets break this down a little further and look at the STi PPP with T25 handling kit vs the full Type 20 (additional remap, exhaust, panel filter)
Perhaps the most startling find was that it’s not the extra power, my STI PPP ran around 290 bhp (hmm where did the other 11bhp go Subaru?) and the T20 a confirmed 330bhp, yet this actually made very little difference to these times. How do I know this you might well ask– because I had the T25 handling kit fitted first and that made all the difference in times. While the T20 remap, exhaust and filter add massively to the whole Scooby experience (oops we're into subjectivity) you can’t measure on a stopwatch the difference this actually makes on the road…So it seems a STi PPP with the T25 handling pack would match a full T20 car, surprising…
Using the Ibiza Cupra to add some reality showed just how good the STi PPP and T20 really are. In all reality the Ibiza was over a minute slower across 7 mile mountain, a good 12 mph slower through the sweeping bend (over hard suspension) and on average 9 minutes slower over the 100 mile trip. With the ESP switched on the Ibiza was much slower again – a way over aggressive system!
The Subjectivity
Power Upgrade. So you might think I would be disappointed that the £1600 cost of the T20 engine upgrades didn’t make such a big difference as the T25 handling kit. Not at all!! There are just so many things you can’t measure on a stopwatch. The pack just adds so much to the whole Scooby experience, the car is more driveable, it sounds fantastic, throttle response is much better and the car runs more smoothly. Where the STi PPP became breathless the T20 is strong and seems to offer even more. In a straight line or around a track (and the T20 has serious ability harass some very exotic machinery but that’s another story for another time!) the difference would probably be clearer but as far as this experiment goes the difference is purely subjective.
Handling Pack. So the real revelation is the T25 handling pack. Although the impact of the kit over standard suspension can easily be measured (15 seconds over 7 mile mountain, 5-8mph sweeping bend, and on average 3 minutes over 100 miles) there is so much more to the story. Car and driver feel totally connected, the feedback through the wheel is transformed every movement of the car can be felt and reacted to instantly. Under braking the car is totally stable and the trademark Impreza ‘wash-out understeer’ is gone - replaced by a superb neutral handling car. When the now mountainous levels of grip (up from massive as standard!) are finally exceeded the car settles into an easy 4 wheel drift which is simple to recover – get it pointing straight - then either apply more power (if the road allows) or brake and turn in again, simple, safe, effective. On standard suspension the PPP was often nervous and uncomfortable and there was always that damn noise from the rear suspension – all cured with this pack. On long journeys with the AST’s set soft the ride is actually more comfortable.
The Outcome
The T20 is the car the STi PPP should be from standard, of that there is no question. If you want to truly feel one with your car and go faster more safely add the T25 handling kit. If you have a standard STi get the T20 pack rather than PPP. If you have a STi PPP adding the T20 pack will just make ownership even more fun, because life is about much more than the numbers on a stopwatch!!
07 March 2006 | 10:37 AM
#2
Tremendous mate, just what I've been looking for to convince me to get the PS AST's.
Although I have a remapped etc.. WRX I have long thought the suspension setup more crutial to real world performance, it's nice to see someone's actually analysed (sp?) this subjectively..!
Good man..!
Although I have a remapped etc.. WRX I have long thought the suspension setup more crutial to real world performance, it's nice to see someone's actually analysed (sp?) this subjectively..!
Good man..!
07 March 2006 | 11:13 AM
#3
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From: In the workshop or under some one elses car. PROJECT RA 09 IS GO.
Well put, more people should look at the brakes/chassis before spending there hard earned cash on BHP, yet another salesman joins the AST/POWERSTATION team..
John
John
07 March 2006 | 11:14 AM
#4
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Cheers Jasonius - enjoy the setup, I always think its worth finding out exactly what you are getting from an upgrade! I keep this data on all the cars I have (especially hire cars
) so I can see just how well they perform.
) so I can see just how well they perform.
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09 March 2006 | 06:36 PM
#8
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From: Wales
Originally Posted by MBK
Then....buy Spec C and start all over again!! Must be worth it for 70kg saving...
Glad to see you back in here. You must have been busy lately. Need to organise a MWR to test the car with the Stage1 handling kit when the weather improves a bit. Not fancying trying to keep up with you and Mike now! Eek.
09 March 2006 | 06:46 PM
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Cheers Gazz - had a week off so back on here!! I was looking at a spanking new red Spec C in Litcho's today - I was so tempted just to buy it there and then!! Trying to wait until this one is 3 years old first (note trying I usually have the breaking strain of a kit-kat...). I actually managed to go to PowerStation and not spend any money...yet...'kangaroo paw' grooved discs on the way next week (if I don't buy the Spec C first - or then again even if I do!!)
09 March 2006 | 07:47 PM
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V5 - the website says 315bhp but I think they are just being modest - they have taken off the Type 20 tag but its the same pack. I know my car which was just an average STi PPP made 330 bhp and many others have too - it varies from car to car but I think realistically its around that level you can expect.
Spen - your words but that's about it yep!! I let the first owner pay for the PPP, I just went for the PowerStation stuff!!
Spen - your words but that's about it yep!! I let the first owner pay for the PPP, I just went for the PowerStation stuff!!
10 March 2006 | 11:32 AM
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From: The Terry Crews of moderation. P P P P P P POWER!!
Nice review mate, the kit sounds very impressive.
I would be interested in hearing your views on the impact of the kit on ride quality compared to the STi PPP.....I don't thin you covered this....although maybe I just missed it.
Regards,
NS04
I would be interested in hearing your views on the impact of the kit on ride quality compared to the STi PPP.....I don't thin you covered this....although maybe I just missed it.
Regards,
NS04
10 March 2006 | 08:14 PM
#16
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NS04,
clearly ride quality is a very subjective area! I think the ride quality is massively improved, even the missus agrees that the previous sick inducing STi bounce and jiggle is gone - especially on the softest setting. Somehow the standard STi used to settle into a kind of rhythmic undulation that upset passengers. We recently did a 600 mile trip, 4 up with no complaints from anyone - and we were still moving on. From a driver perspective its much improved - other than running your hand (painful!) across the tarmac I can't see how you could get much more feedback.
Hope that helps,
Mark
clearly ride quality is a very subjective area! I think the ride quality is massively improved, even the missus agrees that the previous sick inducing STi bounce and jiggle is gone - especially on the softest setting. Somehow the standard STi used to settle into a kind of rhythmic undulation that upset passengers. We recently did a 600 mile trip, 4 up with no complaints from anyone - and we were still moving on. From a driver perspective its much improved - other than running your hand (painful!) across the tarmac I can't see how you could get much more feedback.
Hope that helps,
Mark
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