333pg333

I was 2630lbs with cage through the firewall, glass rear hatch, steel doors and panels except c/f hood, 1/4 tank - no driver.

95ONE

I'm only running 1.5" tubing. Cars 2300lbs and below were allowed that in some rule I saw somewhere years ago. I then ran a 1" tube for bracing to save more weight. I think the weight of my cage is around 150lbs. This is why I've been working so hard to save weight everywhere. it is EXTREMELY hard to lose 150lbs off a 944, that already weighed 2300lbs to start. I think I've covered it, but I'm not exactly sure. only time. (Way too much) will tell.

I'm also pretty sure a 1 3/4" cage will be around 200lbs or more.

TonyG

My wheels are heavy at 58.8 lbs each with NT01's.

Just installed new R6's today. And the wheel/tire combo dropped 3lbs to 55.8lbs.

So the car now weighs 12lbs less.

Once I get the wide body kit on, I'll get some wheels and shave off another 20lbs (5lbs per corner).

But honestly... I really don't want to take any more weight out. I'm right at the top of the class limit at a max of 6.51lbs/hp with R compounds.

I'm going to have to add weight once I go to slicks with a limit of 7lbs/hp.

TonyG

333pg333

Do they mean hp at crank or wheels in that calc Tony?
Our local Porsche Club, and in fact I think nationally, request that we divide the weight of the car in kg's by the kw's at the crank. To get the power at the engine from the wheels they say to multiply by 1.32 in terms of transmission loss.
I'd be pretty certain that this is deemed from the factory. So we get the car dyno'd...usually in whp. Then convert hp to kw, then multiply that by 1.32 and divide this into the vehicle's weight wet with no driver.

TonyG

My cage is 1.75 .120 That's what I have to run at my weight.

But it doesn't really matter much as I have to be at over 6,.51lbs/hp on R's or 7.0lbs/hp on slicks.

The recent dyno on a Dynojet (the official dyno we are required to use) the 3 dyno runs averaged 437RWHP.

At 2944lbs with driver (me as the driver... not the stand-in I had in the car..and with the car now on R6's vs NT01's)..... 2944/437= 6.73lbs/hp

So I'm smack in the middle between the two tires.

Going to slicks will require some weight to be added.

Staying on R's will allow me to add another 15RWHP or drop a few "hard to get lbs.

TonyG

TonyG

It's always RWHP, SAE corrected on a Dynojet.

The weight is always the total minimum weight (driver, car, with a minimal amount of fuel).

TonyG

333pg333

ps, do you also have to have a full tank of fuel?

EDIT: you beat me to it.

btw. 1 litre of water weighs 1 kg. Or 1/4 gallon weighs 2.2lbs. So fuel is heavy.

TonyG

Here's the dynojet run from this week:

Another 15RWHP is very easy to get at this point.... :-)

TonyG

TonyG

You want the car to be practically empty for the calculations. That way if you come off the track with more fuel, you're not under weight... which would get your DQ'ed.

TonyG

333pg333

Yes that makes sense.
Great flat curve...or should I say line, typical of a V8. What surprises me is the lack of really big tq numbers on these V8's. I mean nothing to sneeze at but a warm 2.5L turbo would see that sort of number too. Just not quite as early.

ps, love the name of the dyno shoppe!

TonyG

They do a lot of custom fabrication and a lot of show car "colored chrome" paint. Pretty cool stuff actually. They just did a blue chrome Mustang for the Blue Angles (a US Navy group of pilots that perform air shows for the public for promotional purposes).

I don't really know why they have a dyno there, but they do. And it's a the type that I need to use. $75 for the required 3 runs.

333pg333

Cheap at twice the price!!
Doesn't matter what dyno you run on in a controlled situation. Everyone is using the same. My guess is that people want their car to show as little power as possible for the power to weight figure, but I guess if you fudge things and start streaking away from the opposition they'd check you pretty quick under the weight of all the protests!!

btw I figured out that you'd be about 3.20 power to weight in our classes. Puts you right around a 996 GT3 RSR. Not bad Tony!

TonyG

If you finish a race in the top 3 of your class, you go straight from impound to the scales. Then straight to the portable dyno they bring out (they bring it randomly to various races to keep everybody honest).

If your weight with what ever fuel you still have onboard after the race, and you (the driver) in your race gear....... divided by the dyno result exceeds the limits for your class, you're DQ'ed... zero points.

TonyG

Lemming

Just did mine this morning before I head to Barber for the weekend. I recently added my passenger seat (going to hire a pro coach) and moved my accusump to the rear of the car. Weight is with 1/3 tank of gas and 185 lbs in the drivers seat.

Corner weight 50%
Front weight 50.7%
Left weight 51%

95ONE

Tony, I can only hope my curve looks that flat. Tim, that's pretty damn square. nice.