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Texas Mile is over 900 miles away and about 10 months out if I recall correctly.
That would be like me telling you to go do an event in Monza when Castle Combe is an hour away. You are about as geographically ignorant as many claim about Americans.
My money is important to me, it belongs in my pocket, not yours. If you want to pay for something I personally do not care about, that's your perogative. You and your fellow minions can do what you want. You can go on and on about how great your little "VMax" group is and how great RS is even though they can't tune their way out of a paper bag.
Texas Mile is over 900 miles away and about 10 months out if I recall correctly.
That would be like me telling you to go do an event in Monza when Castle Combe is an hour away. You are about as geographically ignorant as many claim about Americans.
My money is important to me, it belongs in my pocket, not yours. If you want to pay for something I personally do not care about, that's your perogative. You and your fellow minions can do what you want. You can go on and on about how great your little "VMax" group is and how great RS is even though they can't tune their way out of a paper bag.
What a card you truly are - enjoy your car (and your money) in good health. Texas Mile is an example by the way. If there aren't any events nearer then I'm sorry you'll never be able to see what your GT2 can really do which is shame. (212mph if on a standard gearbox). We all drive a few hundred miles to get to VMAX and Elvington is about 300-400 miles for quite a few of us who live down south. No sweat for us.
Can you give me an example of the real world driving conditions that would cause you to be at such a high speed for such a prolonged period of time? Besides at some type of airstrip event? Just curious...
You are suggesting that because our HP figures were measured on a dyno they are somehow invalid in comparison to your "real" load and that's simply an unfair assumption. The majority of EVERY car in the world drives between 60 and 130-140mph even on a endurance event like a road course DE. Our kits perform perfectly under those conditions. So does that make them any better or worse? Are those fantastic results invalidated because we haven't show a 0-300kph? It's an apples to oranges comparison.
Tom you've just hit the nail on the head re how Porsche AG calculate and quote real HP. They really do test the car under full load repeatedly to VMAX. I note Porsche have gone smaller with their VTGS on the 991 turbo. My own view is that if they want more than say 650bhp for their next turbo or GT2 they will not go down the bigger VTG route for the reasons I've stated. I personally think they'll go hybrid or conventional turbos to get to 800bhp if they ever make another GT2 or GT2 RS.
I guess a log like this is in question now. This is what VGTs with modest 580 crankhp can do:
Note how 997 GT2 intercoolers perform with increasing speed.
100-200 km/h 6.57 sec / 280m
100-300 km/h 24.51 sec / 1560 m
200-300 km/h 17.94 sec / 1280 m
100-315 km/h 29.12 sec / 1949 m
-GPS altitude at the start of the run 530 m, at 200 km/h 522 m
-OAT +13C, dew point +12C, 1025 hPa. (OAT on instrument panel +15C)
-Aral 102 (RON) SuperPlus fuel
-Location: Autobahn A1 north of Nürburg, direction Köln
It's 1950 kms from my home to Nürburgring, I do it every year. If there's will, there's ways.
In general the output of every turbocharger is limited by two things, output of compressor and the flow capability of the turbine. Increasing compressor's output is easy with different propellers and housings. The same can be done with turbines too, but what if there's nothing available?
Or nothing's done? The latter is easy to answer...at a certain point increasing the flow -or pressure- only the backpressure increases, exponentially. This causes the increase of EGT and eventually something will melt. Either pistons or turbine wheels.
Easiest way to increase the backpressure is to mismatch compressor and turbine so that the flow capability of the compressor is way too big for the turbine and then run it with too high boost pressure.
That's in general. There's some differences between std .7 turbo and 7. GT2 turbo's hotsides...something I dug out earlier:
GT2 : BV50-2280DCB426.10BVAXO BV50 = turbo type 2280DCB = cold side where
22 = Dex(ducer) 22/10" = 56 mm
80 = d/Dex in % (TRIM) -> 56x0.8 = 45 mm inducer
D,C,B = wheel geometry etc definitions
426.10BVAXO = hotside where
426/405 = turbine housing area in cm2 (4.26 or 4.05) towards the turbine wheel.
10 = housing definition
B = wheel geometry
V = housing geometry
A= design stage
X = housing inlet flange
O = Housing material
So the hotside's scroll's opening to the turbine's inducer is 5% larger and the wheel has 15 dec clip. I've found turbine wheel measurements for .7 turbo (48mm INDucer, 44,5 mm EXDducer = Trim 86 -Tip 9.48mm), but not yet for GT2. Some math can be applied from those numbers, I'll be back.
Now the scroll opening area and thus it's max flow capability is the bottleneck here, there's no wastegate to bypass excessive exhaust flow. Everything flows through it, guide vanes just control how much of the flow will be directed to the turbine wheel.
I guess a log like this is in question now. This is what VGTs with modest 580 crankhp can do:
Note how 997 GT2 intercoolers perform with increasing speed.
100-200 km/h 6.57 sec / 280m
100-300 km/h 24.51 sec / 1560 m
200-300 km/h 17.94 sec / 1280 m
100-315 km/h 29.12 sec / 1949 m
-GPS altitude at the start of the run 530 m, at 200 km/h 522 m
-OAT +13C, dew point +12C, 1025 hPa. (OAT on instrument panel +15C)
-Aral 102 (RON) SuperPlus fuel
-Location: Autobahn A1 north of Nürburg, direction Köln
It's 1950 kms from my home to Nürburgring, I do it every year. If there's will, there's ways.
In general the output of every turbocharger is limited by two things, output of compressor and the flow capability of the turbine. Increasing compressor's output is easy with different propellers and housings. The same can be done with turbines too, but what if there's nothing available?
Or nothing's done? The latter is easy to answer...at a certain point increasing the flow -or pressure- only the backpressure increases, exponentially. This causes the increase of EGT and eventually something will melt. Either pistons or turbine wheels.
Easiest way to increase the backpressure is to mismatch compressor and turbine so that the flow capability of the compressor is way too big for the turbine and then run it with too high boost pressure.
That's in general. There's some differences between std .7 turbo and 7. GT2 turbo's hotsides...something I dug out earlier:
GT2 : BV50-2280DCB426.10BVAXO BV50 = turbo type 2280DCB = cold side where
22 = Dex(ducer) 22/10" = 56 mm
80 = d/Dex in % (TRIM) -> 56x0.8 = 45 mm inducer
D,C,B = wheel geometry etc definitions
426.10BVAXO = hotside where
426/405 = turbine housing area in cm2 (4.26 or 4.05) towards the turbine wheel.
10 = housing definition
B = wheel geometry
V = housing geometry
A= design stage
X = housing inlet flange
O = Housing material
So the hotside's scroll's opening to the turbine's inducer is 5% larger and the wheel has 15 dec clip. I've found turbine wheel measurements for .7 turbo (48mm inducer, 44,5 mm exducer), but not yet for GT2. Some math can be applied from those numbers, I'll be back.
Now the scroll opening area and thus it's max flow capability is the bottleneck here, there's no wastegate to bypass excessive exhaust flow. Everything flows through it, guide vanes just control how much of the flow will be directed to the turbine wheel.
So if I read this correctly you run around 18-19psi is this on oem turbos?
So if I read this correctly you run around 18-19psi is this on oem turbos?
What tune are you running?
0,9 bar for street, 1,3 bar for track. Motronic (ME7.8) is tuned by a local hero, VGT settings by myself. It's basically still a 996 turbo engine with "stuff".. A lot of stuff...
Havent seen a single 4th gear pull from a giac 68mm car, but would love to
I've done lots of 4th gear pulls with my Cobb/Champion 68 car, what data are you looking for?
The vtg turbos may all be limited by the hotside but I can tell you there is a significant difference in acceleration between stock and 63.5vtgs and 68vtgs. I've gone sequentially from stock to stock plus tune to 63s to 68s and documented the results each time.
Dyno comparisons are worthless imho. There are so many ways to get the numbers higher. When we were tuning my car on the 4 wheel Mustang dyno there was a run that showed 650whp and 650wtq and we all were amazed...until we saw the shape of the curve. One massive peak followed by a more "normal" curve. It's the shape of the curve that determines how well the car drives and how repeatable the performance is.
I haven't done a 60-130 with my latest tune and mods but with stock injectors and 5 bar fpr I did 6.9s on pumpgas with 3.0-3.1s 60-100mph time in third gear. Those numbers are similar to what the 63.5vtgs could do on racegas.
I've done lots of 4th gear pulls with my Cobb/Champion 68 car, what data are you looking for?
The vtg turbos may all be limited by the hotside but I can tell you there is a significant difference in acceleration between stock and 63.5vtgs and 68vtgs. I've gone sequentially from stock to stock plus tune to 63s to 68s and documented the results each time.
Dyno comparisons are worthless imho. There are so many ways to get the numbers higher. When we were tuning my car on the 4 wheel Mustang dyno there was a run that showed 650whp and 650wtq and we all were amazed...until we saw the shape of the curve. One massive peak followed by a more "normal" curve. It's the shape of the curve that determines how well the car drives and how repeatable the performance is.
I haven't done a 60-130 with my latest tune and mods but with stock injectors and 5 bar fpr I did 6.9s on pumpgas with 3.0-3.1s 60-100mph time in third gear. Those numbers are similar to what the 63.5vtgs could do on racegas.
If you have any logs on datazap I would love to look at them!
Tom you've just hit the nail on the head re how Porsche AG calculate and quote real HP. They really do test the car under full load repeatedly to VMAX. I note Porsche have gone smaller with their VTGS on the 991 turbo. My own view is that if they want more than say 650bhp for their next turbo or GT2 they will not go down the bigger VTG route for the reasons I've stated. I personally think they'll go hybrid or conventional turbos to get to 800bhp if they ever make another GT2 or GT2 RS.
I don't necessarily agree. Look at the current (or last) GT2-RS. Porsche offered that car with 620bhp using the same VTG turbochargers as the standard 997 GT2. Many individual owners and shops (including us) have dyno tested the GT2RS and found that even that number is a bit understated. Most real-world tests have shown the GT2RS to make about 590-600 peak HP at the wheels, which is another reason why I can't understand why some people find it so hard to believe that 600+ hp at the wheels is easily achievable with VTG's.
For future generations...who knows. My guess is that Porsche will absolutely stick with VTG technology. VTG turbos are already becoming more widely used in a lot of different applications, some of them using much larger turbos then Porsche currently uses. I can't see them sacrificing the linear power delivery of the VTG turbos in exchange for a few more BHP.
To clarify yes I have GT2 hybrid turbos. You're a terrible advert for Champion. I bet they enjoy having you as a customer
I am sure they like getting paid for providing exceptional, outstanding service beyond my high expectation.
How that is is beyond me, but speaking of jokes, Toby's "ultimate VTG" car using conventional turbos is even funnier. And how a company such as RS, who supposedly tune high HP cars, didn't even have a dyno that could tune a VTG car without breaking. Or solder a chip to a DME. Or have someone in house to tune the DME without having to hire specifically for that car. Or supposedly spend so much time mapping the DME that they "wore out" the engine and had to rebuild it. These people you put your faith in are an absolute mess. According to them, VTG can't make power, but breaks their dyno. Experts at tuning, but nobody to actually program the DME. Experts at installation, but can't solder a chip on a board. All these missteps on one car, the joke's right there.
RS and 9e can't even approach Champion's level of expertise, so instead of selling on merit, they sling feces at other companies, just like what you are doing, using ad hominem attacks towards me when I did absolutely nothing to you except offer a path for you to get the data you supposedly want.
Have fun with your underperforming car. I'm done with this thread.
If you have Cobb logs just upload them at datazap.me and share a link!
I have 3rd gear logs. The 4th gear logs are just partial - that's getting into "go directly to jail" territory. I have some 4th gear logs from the track last year but it was a different version of the tune and stock injectors. Injector duty cycle was waaaay up there. Did you want the 3rd gear logs? Or I could wait till I go to the track in the fall and get 4th gear logs.
I am sure they like getting paid for providing exceptional, outstanding service beyond my high expectation.
How that is is beyond me, but speaking of jokes, Toby's "ultimate VTG" car using conventional turbos is even funnier. And how a company such as RS, who supposedly tune high HP cars, didn't even have a dyno that could tune a VTG car without breaking. Or solder a chip to a DME. Or have someone in house to tune the DME without having to hire specifically for that car. Or supposedly spend so much time mapping the DME that they "wore out" the engine and had to rebuild it. These people you put your faith in are an absolute mess. According to them, VTG can't make power, but breaks their dyno. Experts at tuning, but nobody to actually program the DME. Experts at installation, but can't solder a chip on a board. All these missteps on one car, the joke's right there.
RS and 9e can't even approach Champion's level of expertise, so instead of selling on merit, they sling feces at other companies, just like what you are doing, using ad hominem attacks towards me when I did absolutely nothing to you except offer a path for you to get the data you supposedly want.
Have fun with your underperforming car. I'm done with this thread.
Yet none of Champions 68mm vtgs with monster tunes have run and logged 0-300kph. And we are the ones under performing lol.
07-13-2015 | 02:44 PM
A lot of stuff...
