Dyno comparison with and without X50?
03-15-2004, 10:41 AM
#46
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But, if you had another 100 hp available in first gear, from the time it hits to the time you shift is such a short time that you're already lifting.
As for torque, Stage 1 has a peak advantage of 71 lb-ft, but the "area under the curve advantage" is substantial from 3500-6000 rpm. This translates to "punch" and a car that's much more fun to drive IMHO.
05-23-2005, 07:40 AM
#48
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Originally Posted by Bob Rouleau
johnm - The overboost feature of the GT2 engine is mentioned in the GT2 "teknic" description. When I try to get more info I get stonewalled. Once I was asked how I had learned of it. Seems to be a secret. I've never seen more than 1.1 bar on the read-out and that was on the track. On the other hand an X50 is way faster than a regular TT, more than can be explained by 10 percent more power I think. I also wonder why Porsche felt they needed so many engine and transmission mods for a mere 10 percent increase in power. This makes me think that there is truth to the overboost story. As you observed it is not uncommon. My old Audi S4 (the original one with the 5 in line engine) had it and it worked for 40 odd seconds and only in the top 4 gears. The boost gauge showed it working. For a car with 222 rated HP it sure was fast - 0-60 in six seconds which isn't bad for a 4000 lb car with only 222 HP!
05-23-2005, 02:16 PM
#49
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The boost will follow the knock limits set in the Motronic which typically means higher boost around peak torque then tailing off around peak power before rising again to the limiter. True overboost works when you stab the throttle hard and for a few seconds the boost can go higher tha it would on a normal WOT run - this is why the cars feel faster than a set 450hp, cos for a few seconds you will be getting more than that until the knock detection winds the boost back. For comparison my motor will allow overboost up to 1.5bar in the mid range which is probably around the 850NM mark - but this is not repeatable if you just run up through the revs in a high gear (or on a dyno run eg).
05-26-2005, 11:18 PM
#50
I have a GT2 and on the track @ about 5800 in 3rd it will go from .9 to a solid 1.0 and stay there into 4th. I've driven 2 stage 4 GT2s on the track supposedly 600+hp and even though they show more boost (1.2) I swear the throttle response was slower than my stock car. Maybe there faster from 130 up but if I would have spent $10k on the mods I would have been disappointed. The car I was impressed was Fred's non X50 with a chip and exhaust + PSS9s. It pulled a solid .9 and spooled up really quick and handled great for a 3500lb car. Felt as quick as a X50, I think you get more bang for your buck with chipping a non X50. I don't see the cost reward ratio in some of the X50 mods. I'm not saying you cant improve on the dyno # or cut a1/2 second of a 1/4 mile. It just doesn't seem worth it to me. But then again what do I know? carl
