HP to Weight Ratio Thoughts

[gruen911]

Guys,
This morning while walking my dog I was thinking about my little 67 with 160hp and weight of 1030 (well, since I have a sunroof coupe, the weight is probably more like 1050).
Anyway, I was thinking more about that chart that someone posted a few days ago which showed a comparison of hp/rev's between the 911R and the 911S - and how that curve goes almost vertical to 8k rev's for the 911R versus the 911S which peaks in the high 6's. As I thought about what it would be like to buy or build a engine with more hi rev'ing power up top like the 911R (unlike the RS), I started to think about how expensive the cost of building a 911R engine would be - and how unsuitable for street use a 911R engine would be. Then I started thinking about going with more streetable cams etc. before realizing that my best bet was to go in the opposite direction and try to get extra power by dropping the weight instead of increasing building a higher hp engine!!!
Here is what I figured:
My 1967 911 coupe weighs around 1050/ hp 160. That would mean a hp to weight ratio of 0.152
To come up with the comparable horse power to weight 210hp that the 911R engine (and 911RS) produces, I calculated that I would have to drop 210 lbs. That's relatively easy if you toss out the passenger and the passenger seat (even more if you have factory recaro sportseats). But if you are driving by yourself, where would be the best place to save the weight - for the cheapest amount of money? In other words, how much weight could I save by swapping out steel for fibreglass fenders in front and hood and engine lid? How about changing to plexiglass in the front and rear windshields, and plexiglass quarter windows. How about going with 911R turn signal and brake light assemblies all around?
Don't get me wrong guys. My 67 911 with 160 is plenty of hp. I am just looking for ideas from others who have experimented with trying to bring down the weight on their cars (but still keeping, heat and other daily driver luxuries). I figure,the less it weighs, the more hair raising the driving experience would be....

[pu911rsr]

As Colin Chapman used to say, add lightness. But also don't forget torque not horsepower accelerates the car at low speed, so cubic inches don't hurt either, at least for the street.
Phil

[gruen911]

As Colin Chapman used to say, add lightness. But also don't forget torque not horsepower accelerates the car at low speed, so cubic inches don't hurt either, at least for the street.
Phil

Hi Phil,
Appreciate your comments, but my focus is not really on wanting more low end power (belly). I am not looking to blow anyone off the line, so a higher displacement engine is not my priority. I guess I am looking for more power and speed once the car is moving and climbing the rev range in second gear (more snap) . Also, more power thru wide turns. A higher displacement engine is not what I am looking for. Otherwise I could go buy a 2.7-3.2 motor and sell my little 2.0 liter S screamer - NOT...

[schmidt]

Less is more indeed, I run a 320hp 3.8 Varioram in a 2100# car. It is not as much the horsepower in some cases as it is the torque. With that kind of horse power coupled with an unbelievable flat torque curve that will prevent you from grabbing anything off the dash at 2000 rpms and above approaches absolute savageness. This same motor in a 3000# car is evil enough but when a third of the weight is removed it goes from playing to a religious experience. I highly recommend it.

[B D]

Here's a good resource for weight http://rennlight.com/

Here are a few free ideas for lightening things up:
remove blower motor 8 lbs
remove rear seats 12+ lb
remove smugglers box lid
remove washer tank .5 lb
remove hood shocks
remove rear grill
remove horn grills
remove radio and speakers

Items that cost:
smaller battery
plexi windows
R lights - saves 7 lbs
Fiberglass panels
RS door panels
944 wiper motor - saves 6 lbs

Also keep in mind where the weight is being removed, the balance of the car can be altered. You can also relocate items like a battery to the smugglers box to bring the weight closer to the center of the car improving balance.

[pwd72s]

Based on Jeff's figures, he has 6.56 pounds per horsepower...pretty impressive. Some comparitive figures with new cars.
Ford GT...6.3
Porsche 911GT2... 6.6
Lamborghini Gallardo...6.3
Ferrari FF430...6.6
Dodge Viper...6.8
And the current champ? Ewwww! Ick! It's a:
Corvette Z-06...6.2

It pains me to write this, but that's gotta be one hell of a bang for the buck!

[beginner]

Instead of a 3.8 Varioram, why not build a short stroke 2.8 MFI? 300+ horsepower, 8500rpm.

[RandyWebb]

I hope to update the rennlight database in the near future - mostly interior & trim items are what I have to add.

But what you described in 2nd gear is the exact def'n of torque in the midrange...

Drive a Honda S-2000 to see what a small hi reve motor is like.

[CurtEgerer]

Actually, the reigning Champion is the 2005 Koenigsegg CCR at 3.2 lbs/HP

Others of interest:

1974 911 Carrera 3.0 RS - 9.4 lbs/HP

1973 Lamborghini Muira - 7.1

959 - 6.6

[schmidt]

Here is the real info Paul, I finished the motor and dropped it off at the shop, it was run on the dyno and made an amazing 326hp and 291 foot pounds of torque. The car weight is 2090# dry. Get this the motor made 275 foot pounds of torque at 4000 and the 291 was at 5500. Above the spec for a stock Euro RS 3.8 Varioram. For comparision Barretts made 308hp and 277 torque at 5500 max.