Dyno comparison with and without X50?
03-10-2004, 08:58 AM
#31
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"The X50 and GT2 have a "secret" overboost feature giving a couple lbs more boost for 45 seconds. This does not show up in steady state HP tests."
Whilst I have not actually seen a 996tt or X50/GT2 boost curve on the road (by looking at a guage) I am certain that this overboost feature you are reffering to is not quite how you describe it. The overboost is controlled by the ECU and it is not for a preset time, ie it may be for 2 seconds, or 7 seconds, and happens around peak torque - it is basically the ECU allowing the boost to raise to a higher level than that at peak power, and then the boost will reduce as detonation approaches. The stock 996tt also has this feature, but the GT2/X50 probably has more "aggressive" mapping and also the bigger turbos and intercoolers probably allow the air to be a bit cooler, hence not as close to detonation at any given point therebye allowing more boost. This feature is the best bit about these Motronic systems.
Whilst I have not actually seen a 996tt or X50/GT2 boost curve on the road (by looking at a guage) I am certain that this overboost feature you are reffering to is not quite how you describe it. The overboost is controlled by the ECU and it is not for a preset time, ie it may be for 2 seconds, or 7 seconds, and happens around peak torque - it is basically the ECU allowing the boost to raise to a higher level than that at peak power, and then the boost will reduce as detonation approaches. The stock 996tt also has this feature, but the GT2/X50 probably has more "aggressive" mapping and also the bigger turbos and intercoolers probably allow the air to be a bit cooler, hence not as close to detonation at any given point therebye allowing more boost. This feature is the best bit about these Motronic systems.
03-10-2004, 07:17 PM
#32
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Bob's observation merits comment. The Excellence article comparing a heavily modded car (previously widely discussed on this forum) to a standard GT2 revealed how hard it is to get substantial performance improvements. I had long ago posted that the X50 felt very strong in comparison to 2 vintage racers I own with engine dyno numbers well in excess of 500hp (tested on the engine dyno of the shop that prepared engines for a prominent "factory" Winston Cup team.) I'm not criticizing the tuner efforts ( I may well be a customer post-warranty), but it is possible that the major impact of more hp may be most measurable in the speed ranges Americans rarely see. While I've been over 160mph many times on the track, fear-of-losing-license-and-endangering-others keeps me below 100mph for 99% of my driving. So, I personally haven't felt an urgent need to increase hp over the X50. Still, it would be good to see somebody put an X50 on a dyno immediately after a modded car, so the "what do these numbers mean" question would be answered. As to reliability, I think it's remarkable, and a testament to the tuners and to Porsche engineering, that not a single poster has ever alluded to engine failure related to mods. While ultimate longevity may ultimately be impacted, I doubt that 5% of owners will ever put on enough miles to test the question. That high level of reliable performance has magnified the issue of the ceramics. AS
03-10-2004, 08:56 PM
#33
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Alexander,
I read that article on Chad's car running with the stock GT2, he was faster by a full sec. in the 1/4 mi., and that was because they were sandbagging it as to not get kicked off the track (which they did anyways because they went too fast. I agree with you that the X50 puts out some extraordinary numbers for what it is "supposed" to be, and probably where the real measurable difference of some of these 600+ hp monsters would be in the 125 mph + range. The X50 is about as crazy/perfect an everyday car as you can get (it ran neck & neck with a 500 hp Viper up to 100 mph). Many of the people with 600+ hp complain their cars are not real everyday drivers.
I read that article on Chad's car running with the stock GT2, he was faster by a full sec. in the 1/4 mi., and that was because they were sandbagging it as to not get kicked off the track (which they did anyways because they went too fast. I agree with you that the X50 puts out some extraordinary numbers for what it is "supposed" to be, and probably where the real measurable difference of some of these 600+ hp monsters would be in the 125 mph + range. The X50 is about as crazy/perfect an everyday car as you can get (it ran neck & neck with a 500 hp Viper up to 100 mph). Many of the people with 600+ hp complain their cars are not real everyday drivers.
03-11-2004, 06:50 AM
#36
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Originally posted by ypshan
How does one "invoke" the secret overboost feature of X50?
How does one "invoke" the secret overboost feature of X50?
03-12-2004, 11:45 AM
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A couple of points: I am glad to see guys coming forward and defending the value of the X-50....The whole " just chip your TT and it will kill an x-50 argument doesn't hold water at all" That type of mentality might be expected of a 16 year old interested in stop light to stoplight racing, but for me, I take my X-50 to the track, and run it hard.....and I want to be able to continue to do that year after year.....I think there is far more depth to the X-50 package than is expressed in little dyno graphs....The kind of depth that will show it's value in longevity, track days, and overall enjoyment, etc.
as for secret boost .....I saw 1.1Bar the other day, momentarily as i was flooring my unchipped X-50 through 5th gear.....
as for secret boost .....I saw 1.1Bar the other day, momentarily as i was flooring my unchipped X-50 through 5th gear.....
03-12-2004, 01:05 PM
#38
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Originally posted by JP Schnitzer
A couple of points: I am glad to see guys coming forward and defending the value of the X-50....The whole " just chip your TT and it will kill an x-50 argument doesn't hold water at all" That type of mentality might be expected of a 16 year old interested in stop light to stoplight racing, but for me, I take my X-50 to the track, and run it hard.....and I want to be able to continue to do that year after year.....I think there is far more depth to the X-50 package than is expressed in little dyno graphs....The kind of depth that will show it's value in longevity, track days, and overall enjoyment, etc.
as for secret boost .....I saw 1.1Bar the other day, momentarily as i was flooring my unchipped X-50 through 5th gear.....
A couple of points: I am glad to see guys coming forward and defending the value of the X-50....The whole " just chip your TT and it will kill an x-50 argument doesn't hold water at all" That type of mentality might be expected of a 16 year old interested in stop light to stoplight racing, but for me, I take my X-50 to the track, and run it hard.....and I want to be able to continue to do that year after year.....I think there is far more depth to the X-50 package than is expressed in little dyno graphs....The kind of depth that will show it's value in longevity, track days, and overall enjoyment, etc.
as for secret boost .....I saw 1.1Bar the other day, momentarily as i was flooring my unchipped X-50 through 5th gear.....
X50 RS stage1
3000rpm 200KW 200KW
4000 260 310
5000 320 345
6000 330 355
6500 330 353
7000 n/a 348
The RS stage 1 package is clearly going to be much quicker than the X50. The new GT2 with 355KW does 0-200kph in 12.5 secs !! (OK it is 100kg lighter) The X50 theoretically should be more reliable for the usage you mention (bigger turbos being less stressed) however I am struggling to find the "depth" you refer to ? As usual Porsche are just making $$$
The X50 I have tried was seriously in need of a chip package
03-12-2004, 07:46 PM
#39
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Originally posted by Bob Rouleau
The X50 and GT2 have a "secret" overboost feature giving a couple lbs more boost for 45 seconds. This does not show up in steady state HP tests. If it were my choice and I wanted the extra power I would order the X 50.
The X50 and GT2 have a "secret" overboost feature giving a couple lbs more boost for 45 seconds. This does not show up in steady state HP tests. If it were my choice and I wanted the extra power I would order the X 50.
03-13-2004, 08:26 PM
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Originally posted by 1988952
There are no genius tuners in the US,only peak horsepower dynoqueens. I have never seen a US tuner trying a laprecord on the Ring (like Gemballa or Techart) or participate in the German tuner GP with all the top european companies present.
There are no genius tuners in the US,only peak horsepower dynoqueens. I have never seen a US tuner trying a laprecord on the Ring (like Gemballa or Techart) or participate in the German tuner GP with all the top european companies present.
03-13-2004, 11:49 PM
#41
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Re: "The X50 I tried was seriously in need of a chip package"
My X50 just reached 21,000 miles during my usual 50 mile commute, for which my computer tells me my average speed is generally 50mph. Most of this is on US 12, a winding lakefront 2 lane with little speed enforcement but lots of deer, and I94, a flat 6 lane with truck traffic but pretty wide open during the times I drive., then a stretch with 6 stop lights which brings the average way down (to 50) I was trying to find exactly where my car needed a chip package, and I failed.
You can't use any more boost in 1st or 2nd, since you'r out of those gears so quickly, you never sustain full boost. WOT thru the middle of 3rd gear takes you to lose-your-license speeds very quickly. I don't know about anybody else, but I rarely if ever am at sustained WOT above4500rpm in 4th, 5th or 6th on open roads. Granted, on a long-straight track like Elkhart Lake, you can always use more power. But on the street, I can't seem to find the opportunity. I have driven a standard tt, and can feel the difference to the X50,
I currently have 4 vintage racers, 2 with engine dyno numbers in excess of 540hp. All are street licensed. Neither of the high hp cars can slice thru traffic any more quiclky than the ttX50. I previously had a street licensed Lola 163 CanAm car (autoweek article "The celebrated Lola T163 of Munster Indiana) that was competitive with all but the baddest Mclarens. I drove that car on the street using the racing rain tires. I don't think it got to 50 any quicker than the X50- tho it was more limited by wheelspin and axle tramp. It had 611 real hp, but on the street, I don't think I could use half of those. I guess my point is that I suspect higher dyno numbers from a chip package may yield a momentary sense of greater acceleration, but except for track use, I think you would rarely experience it.
My concerns about the track are those related to testing under the stresses of the mods. I'm confident my X50 can take it, but only time will tell about the chipped cars. If you saw the shootout thread on the "other" board, one infamous poster had unresolvable track problems with his (professionally) heavily modded car. The others did well. AS
My X50 just reached 21,000 miles during my usual 50 mile commute, for which my computer tells me my average speed is generally 50mph. Most of this is on US 12, a winding lakefront 2 lane with little speed enforcement but lots of deer, and I94, a flat 6 lane with truck traffic but pretty wide open during the times I drive., then a stretch with 6 stop lights which brings the average way down (to 50) I was trying to find exactly where my car needed a chip package, and I failed.
You can't use any more boost in 1st or 2nd, since you'r out of those gears so quickly, you never sustain full boost. WOT thru the middle of 3rd gear takes you to lose-your-license speeds very quickly. I don't know about anybody else, but I rarely if ever am at sustained WOT above4500rpm in 4th, 5th or 6th on open roads. Granted, on a long-straight track like Elkhart Lake, you can always use more power. But on the street, I can't seem to find the opportunity. I have driven a standard tt, and can feel the difference to the X50,
I currently have 4 vintage racers, 2 with engine dyno numbers in excess of 540hp. All are street licensed. Neither of the high hp cars can slice thru traffic any more quiclky than the ttX50. I previously had a street licensed Lola 163 CanAm car (autoweek article "The celebrated Lola T163 of Munster Indiana) that was competitive with all but the baddest Mclarens. I drove that car on the street using the racing rain tires. I don't think it got to 50 any quicker than the X50- tho it was more limited by wheelspin and axle tramp. It had 611 real hp, but on the street, I don't think I could use half of those. I guess my point is that I suspect higher dyno numbers from a chip package may yield a momentary sense of greater acceleration, but except for track use, I think you would rarely experience it.
My concerns about the track are those related to testing under the stresses of the mods. I'm confident my X50 can take it, but only time will tell about the chipped cars. If you saw the shootout thread on the "other" board, one infamous poster had unresolvable track problems with his (professionally) heavily modded car. The others did well. AS
03-14-2004, 05:52 PM
#43
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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!
03-14-2004, 10:15 PM
#44
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You can't use any more boost in 1st or 2nd, since you'r out of those gears so quickly, you never sustain full boost.
You might not need more boost in 1st or 2nd, but I do.
03-15-2004, 12:31 AM
#45
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Dock,
No disagreement with your analysis. 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. The time the power is available doesn't transelate to a substantial difference in elapsed time, at least in my opinion, in my driving style.With more torque, ideally you'd lengthen first gear to the 50-60 mph range. Then, the power increase would be much more apparant.
Since I don't do all-out standing start launches, I can't speak from experience regarding longitudinal acceleration in that setting, but I'd concede thata more powerful car might have an easier time getting optimal 4 tire slip for timing purposes. AS
No disagreement with your analysis. 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. The time the power is available doesn't transelate to a substantial difference in elapsed time, at least in my opinion, in my driving style.With more torque, ideally you'd lengthen first gear to the 50-60 mph range. Then, the power increase would be much more apparant.
Since I don't do all-out standing start launches, I can't speak from experience regarding longitudinal acceleration in that setting, but I'd concede thata more powerful car might have an easier time getting optimal 4 tire slip for timing purposes. AS