I've been wondering for a while now exactly how much my car weighs - 2017 C2S with the following (trying to quantify as many options as I can so others can have a reference):

• RAS
• Metal sunroof
• 20" wheels
• 18 way power seats
• Leather interior
• SPASM, sport Chrono
• PSE
• ​​​​sport design rear mirrors
• Bose sound system

This morning I had the fantastic idea that my local transfer station (dump site for those of you not familiar with the term) has a scale to weigh how much construction debris that people dump (they charge by the pound), so I thought I'd see if they could weigh it. The answer was yes.

So, full fuel, full oil, single occupant (me), the car weighs 3,560lb.

Fuel weight of 93 octane is around 6.3lb/gallon, for a full fuel weight of 91.35lb

I weigh 155lb.

That means the car with no fuel weighs 3,315lb. I guess that's pretty close to what Porsche advertises.

Next, I have a little OBD-II Bluetooth sensor that I can connect to Torque Pro on my phone. If you set up your car profile with the correct vehicle weight including occupant - which I did, because I just weighed it (1615kg) - you can do an acceleration run (which I did, safely, via an on ramp to a highway) and it will estimate your peak horsepower at the wheels.

Some of you may know I have recently upgraded my car to the APR GTS turbos + 93 octane tune. Their dyno charts show a 554HP max on 93 octane. Torque Pro knows nothing about this.

Well, this is where things really get interesting and fun. I did the run, and it showed 482.2hp at 7136rpm at the wheels.

Assuming a 15% drivetrain loss, that comes out to be, wait for it, ...

554.53HP..

Yes, I know it's not a dyno. Yes, I know it's an estimate. But holy exact match to APR's claimed numbers, batman!

 

I know what you'll be talking about at the next Porsches & Pastries event.

 

Buy a dragy

 

Yep! Punch in all the right numbers and you can get shockingly accurate dyno charts from a simple datalog. Find flat road, get your weight, gearing, frontal area, drag coefficient, air temperature, and relative humidity, and you're going to be just about as accurate as any loaded dyno spitting out an SAE corrected chart.

Did that when I first turbocharged my Miata many years ago. The curves were identical to the later dyno I did, and the numbers were within something like 6hp.

 

>>I've been wondering for a while now exactly how much my car weighs...<

This is heavily dependent on your oil level; min, max or somewhere in between.

DaveGee

 

I have one. It doesn't do HP calculations.

​​​​​​​1 quart of 0W40 oil weighs 1.7lb. The distance between min and max levels of oil is a max of 2 quarts or 3.4lb. Also, I weighed my car literally 5 minutes before doing this.

 

I threw my car on a scale a while back for fun, was between 1/4 -1/3 tank of gas. Without me in the car and got 3193.

No RAS
Slicktop
7MT
No active wing
No cats.
^ would be the bulk of the weight savings. I was pleasantly surprised.

 

[QUOTE=enzotcat;17354721]I have one. It doesn't do HP calculations.



Since you have one, do a 1/4 mile run and calculate your trap speed. Since you have the weight, you can use an online calculator to determine estimated hp. Do you have any trap speed data on it yet?

 

No trap speed data yet - not going to do it on a public highway because there's too much traffic around and I don't want to get thrown into jail if I get caught 🤪, and haven't had an opportunity to go to the track or dragstrip as yet.

 

Smart man.

 

The sarcasm of my post above was obviously lost. Aren’t you the guy that was obsessing about his oil level the other day? No winky emojis from me.

Carry on.

DaveGee

 

snrk

I definitely missed this at first.

 

Oh dear lord, yes. I am so sorry, I completely missed the snark. And an excellently done snark it was too!!! And yeah, I was obsessing about my oil level amongst multiple other things because I have WAY too much time on my hands at the moment.

 

Generally I leave my cats at home when I go out - they don't like traveling in cars, so you could say that my car's weight was catless.

I'll show myself the door...