Power-to-Weight

[MoodySara]

My son has a CTR, as do I.
We were talking about its power and handling compared to some Porsche models I've owned. He asked how some of the earlier 911s could perform with the limited power they had.
That lead to a power-to-weight discussion.

My first Porsche was a 1969 911T that I bought new. It had a 2-liter, carbureted flat 6 that made (wait for it) 110 HP. It was light, though - 2,249 lbs. Weight/Power=20.5 lbs./HP. Fun car, good grip, very good handling, just not lots of power.

The next was a 1982 911SC, also new. 3-liter injected flat 6 making 180 HP. It had gained some weight, though, and weighed 2,557 lbs. Weight/Power=14.2 lbs./HP. Excellent handling, adequate power for the time. Excellent daily driver.

Then a used 1981 911 Turbo. 3.3 liter turbocharged, injected, flat 6, making 300 HP. More weight - 2,976 lbs. Weight/Power=9.9 lbs./HP. This was also a daily driver. Better that most people expected, even in snow.

The current CTR has a 2-liter, injected, turbocharged, engine, making 306 HP. It weighs 3,084 lbs. Weight/Power=10.1 lbs./HP.

That makes the CTR about the same as the 1981 911 Turbo on paper. But, the CTR is hugely more drivable. The Porsche's power was all top-end. It had a 7.0/1 compression ratio and a big turbo. So, next to no power down low.

Of these cars, I'd say I like the current CTR.

I haven't driven the CTR on a track. I did drive all the Porsches on track. The Turbo was the quickest, not surprisingly. But, driving street cars, even good ones, on race tracks convinced me that street cars aren't very good race cars.

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[vitooooo]

so your trying to compare the technology of today, to the technology 40 years ago?

i am not sure what the point of this thread is?

 

[wildbilly32]

Well...there is much more than just hp to weight when comparing cars. I have a 2005 Porsche 996 C4S(water cooled non-turbo) with a reconstructed/improved engine. The dyno'd hp(for whatever that's worth) is 380. Car weighs @3,200#'s(all wheel drive). The torque curve was also improved as it now comes in full @2,500rpm and pretty much stays there to redline. It is smooth and deceptive. The CTR with the turbo is much more "peaky" I.E.: when the turbo comes in it comes in "hard".

Two completely different vehicles. Completely different feel/experiences. Both are fun to drive. I plan to keep them both as long as I can gracefully get into and out of them!

 

[MoodySara]

Well...there is much more than just hp to weight when comparing cars.

You're right, of course.
This started as a conversation about how the older cars, even like Porsche, could have been such fun to drive even with only 110 HP (the 911T). Weight explains part of it.

The older turbos were all about top end, not drivability. Modern ones are better, especially the twin-scroll versions.

Normally aspirated cars almost always have better looking torque curves like your Type 996, but they need more cubic inches to do it.

They can all be fun. As long as you're not racing that's what matters.

 

[typearghhhh]

My son has a CTR, as do I.
We were talking about its power and handling compared to some Porsche models I've owned. He asked how some of the earlier 911s could perform with the limited power they had.
That lead to a power-to-weight discussion.

My first Porsche was a 1969 911T that I bought new. It had a 2-liter, carbureted flat 6 that made (wait for it) 110 HP. It was light, though - 2,249 lbs. Weight/Power=20.5 lbs./HP. Fun car, good grip, very good handling, just not lots of power.

The next was a 1982 911SC, also new. 3-liter injected flat 6 making 180 HP. It had gained some weight, though, and weighed 2,557 lbs. Weight/Power=14.2 lbs./HP. Excellent handling, adequate power for the time. Excellent daily driver.

Then a used 1981 911 Turbo. 3.3 liter turbocharged, injected, flat 6, making 300 HP. More weight - 2,976 lbs. Weight/Power=9.9 lbs./HP. This was also a daily driver. Better that most people expected, even in snow.

The current CTR has a 2-liter, injected, turbocharged, engine, making 306 HP. It weighs 3,084 lbs. Weight/Power=10.1 lbs./HP.

That makes the CTR about the same as the 1981 911 Turbo on paper. But, the CTR is hugely more drivable. The Porsche's power was all top-end. It had a 7.0/1 compression ratio and a big turbo. So, next to no power down low.

Of these cars, I'd say I like the current CTR.

I haven't driven the CTR on a track. I did drive all the Porsches on track. The Turbo was the quickest, not surprisingly. But, driving street cars, even good ones, on race tracks convinced me that street cars aren't very good race cars.

ok

 

[MadMage]

Yea... power to weight is something important to look at for performance, but so is torque, and perhaps even more importantly the power curves. Because if the curves suck, so does the car

And of course, none of us focus on the power or torque of a CTR. Handling is critical to fun. And weight and suspension geometry are key to handling. Suspension technology (geometry and adaptive control) have come a long ways in the last couple decades. Remember when when thought McPherson struts were all that?

I haven't driven the CTR on a track. I did drive all the Porsches on track. The Turbo was the quickest, not surprisingly. But, driving street cars, even good ones, on race tracks convinced me that street cars aren't very good race cars.

You should. Have a HPDE/Track day with your son. You two will have a blast. As for making a good race car... yeah that's true I guess. But HPDE isn't racing and street cars (generally) don't have full cages, slicks, fire suppression and emergency cut-offs. But, the CTR platform has been doing well in the professional racing circuits for some time. Just look at the TC races you can find world-wide.

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