How 'special' is the new GT2RS engine really?
#76
#77
I'm also an engineer - its one of my faults too well played. I'm pretty sure we understand one another and our different perspectives Cheers.
#78
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Moreover when the settings are in nutter mode with the anti lag system active (keeps the throttle open during on off throttle) the boost is pretty much instant, not linear enough for the sub 2 foot adjustability but that will always be the domain of a N/A motor IMO.
#79
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it s actually the opposite
There s no turbo lag with dual clutch trasmission that can be a loss of control feeling in some circumstancies
There s no turbo lag with dual clutch trasmission that can be a loss of control feeling in some circumstancies
#80
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- A 997 Cup reaches peak 0.72G @ 5,000RPMs at the tire but has slicks. (0.52Gs @ 3,000RPMs)
- A 991 Turbo S 1st generation peak 0.8Gs. @3,000RPMs upwards
All above are approximate.
#81
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A 1969 911 (912) with carbon body panels and PCCB's is a FAR lighter car than a 964. And Pete has a 6speed gearbox.
Build thread in his signature here: https://rennlist.com/forums/porsche-...9-gt3-cup.html
Build thread in his signature here: https://rennlist.com/forums/porsche-...9-gt3-cup.html
#82
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A 1969 911 (912) with carbon body panels and PCCB's is a FAR lighter car than a 964. And Pete has a 6speed gearbox.
Build thread in his signature here: https://rennlist.com/forums/porsche-...9-gt3-cup.html
Build thread in his signature here: https://rennlist.com/forums/porsche-...9-gt3-cup.html
Wow.. And those are not narrow tires
Roughly estimated at peak 0.77G acceleration in 2nd gear based on 993TT box with the listed weight.
#83
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#84
I have to say I enjoy the technical discussions with logical (not butt-hurt) people with different views.
Why would you need to make on-off throttle adjustments mid corner? Neutral throttle through the corner and gradual acceleration on the way out? Why would there be lag in this situation? Adjusting the throttle to play with the traction limit would upset the balance with a turbo or NA car especially with a 911, although it can be fun. I would think that turbo lag would only be an issue if you close the throttle and then open it again expecting instant linear response. If you need to do this in a corner didn't you over brake?
My 3RS has turbo lag in low rpm range. I press the gas and not much happens for a bit. But maybe it's just the relatively low torque between 1500-2500 rpm. NA cars don't have linear response curves either.
The problem is that if you want a lot of horsepower and torque it's hard to get that from an NA engine. Even the 812SF has less torque than the 2RS. Some people like miata's some people like the feeling of torque.
Why would you need to make on-off throttle adjustments mid corner? Neutral throttle through the corner and gradual acceleration on the way out? Why would there be lag in this situation? Adjusting the throttle to play with the traction limit would upset the balance with a turbo or NA car especially with a 911, although it can be fun. I would think that turbo lag would only be an issue if you close the throttle and then open it again expecting instant linear response. If you need to do this in a corner didn't you over brake?
My 3RS has turbo lag in low rpm range. I press the gas and not much happens for a bit. But maybe it's just the relatively low torque between 1500-2500 rpm. NA cars don't have linear response curves either.
The problem is that if you want a lot of horsepower and torque it's hard to get that from an NA engine. Even the 812SF has less torque than the 2RS. Some people like miata's some people like the feeling of torque.
#85
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Why would you need to make on-off throttle adjustments mid corner? Neutral throttle through the corner and gradual acceleration on the way out? Why would there be lag in this situation? Adjusting the throttle to play with the traction limit would upset the balance with a turbo or NA car especially with a 911, although it can be fun.
This great article explains this in much more detail, especially the graphs on Pages 2 and 3:
http://www.motoiq.com/MagazineArticl...r-Control.aspx
#86
#87
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I drove the 991 and 991.2 turbo cars. I can feel AND hear the lag. No need for a boost gauge in the dash !
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I will go listen to my turbo lag with bccars now
#89
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Throttle response is not linear in a turbo car- turbos respond different based on throttle, rpm, load on the engine going up or down a hill, engine temp, your facial expression, etc etc. Whether or not you define this lack of linear response as lag is semantics, but it is a fact. It is also something that you learn to drive around and deal with. I love tracking turbo cars.
NA car is linear and mostly predictable on throttle. NA car is pretty much same response at the same time, every time. You can focus more on driving the car, steering inputs, what chassis is doing mid corner, what tires tell you, etc etc. I learn more and improve skills much more driving my NA car, and it translates over and makes me faster in my turbo car. It is so much easier to learn a technique in something that is linear.
Even with a high compression ratio mostly NA design engine with turbos added, yes response is great but you still get the non-linear wave of power when the turbos light up. Complicates that whole balance the throttle thing, but you learn with seat time/experience what to expect and how power comes on and chassis handles it and correct way to react in the specific car.
One is juggling, other is juggling on a unicycle. Easier to learn what to feel for and what is going on and what to look for without the added variable of the unicycle... or in this case, the turbochargers
NA car is linear and mostly predictable on throttle. NA car is pretty much same response at the same time, every time. You can focus more on driving the car, steering inputs, what chassis is doing mid corner, what tires tell you, etc etc. I learn more and improve skills much more driving my NA car, and it translates over and makes me faster in my turbo car. It is so much easier to learn a technique in something that is linear.
Even with a high compression ratio mostly NA design engine with turbos added, yes response is great but you still get the non-linear wave of power when the turbos light up. Complicates that whole balance the throttle thing, but you learn with seat time/experience what to expect and how power comes on and chassis handles it and correct way to react in the specific car.
One is juggling, other is juggling on a unicycle. Easier to learn what to feel for and what is going on and what to look for without the added variable of the unicycle... or in this case, the turbochargers
#90
It's actually a 4:1 R&P from a 993 cup car, should get you to right around .95 Gs and then I think our math is aligned. No question you've still got me for low end torque... until I can find coin to spring for the 4.0L upgrade, anyway