gatti-man

Another good idea. I have one on my race bike.

Vette @ 71

The debate is about technical accuracy. The benefit of reduced curb weight is lower ET's and is supported by the physical world..

Power to weight ratio has no basis in the natural physical world for predicting ET benefits.

Not a good analog to drag. Drag is also governed by the natural physical world. It is predictable and measurable.

tail_lights

Coming from someone who does this made me

propain

There is no technical debate since the calculation of predicted HP gains by shedding weight is a theoretical number and not a scientific one. I'm surprised you have never heard of this calculation before. Its quite common in the race world to calculate theoretical HP gains by shedding weight.

Otherwise I'm not going to sit here and debate drag coefficients of vehicles and there predictable power gains over the internet. Everyone is an engineer on this forum. I love it.

0Anthony @ LGMotorsports

Depends on the car. We had the Tilton in a few ZR1's and they have so much torque it doesn't really matter. Still takes some tuning work for a stable idle...but they drove nice. Now on a stock LS1, they are a pain to drive as a street car.

pkincy

One CAN argue that weight makes no difference just like one CAN wear a Mink Coat in July in Az. But I never would.

Weight makes a difference. But quite often where that weight is, can make more of a difference. But it depends on what you are doing. Drag racing it makes a difference more from the inertia to get the car moving than the power to weight I would think, but the power to weight does make a difference when the car hooks. Drag racing is not a good test of how lighter weight helps as a car set up for the twisties will be much slower than a heavier car set up specifically for Drag Racing. Drag Racing you want the car to transfer the proper amount of weight at the right time.

Heck for AutoX a common cheat in the stock classes with live rear axles was adding 50 lbs of truck chains over the right rear wheel. It helped the cars differential coming off low speed corners. For RRing there is a HUGE benefit to losing weight. So much so that in the preparation of a RRing car you actually will investigate each fastener to see if a lighter one will do. So that stopping and starting many times a lap makes weight absolutely critical. Other autosports less so.

383

So where would you draw the line for a barely streetable clutch? something you could get on/off the trailer or off a stop sign in front of a cop

gmkillr

What seat mounts save 40 lbs?

MTPZ06

I've seen people shave nearly 100lbs with three simple things...B&B LT's, Akra Ti Evo exh system (no longer in production), and coleman rotors.

Z06Ronald

There are four seat bases/mounts in the Z06 OEM and Aftermarket Parts Weight List. See this link and the first post on the first page in the thread.

OEM Drivers Seat Base: 26 lbs
Pfadt Seat Mount: 5.4lbs

OEM Passenger Seat Base: 10 lbs
Pfadt Seat Mount: 5.4lbs

which accounts for ~ 25 lbs weight loss.

I have copied these data into the spreadsheet "as is", but I have no means to verify their accuracy (via a link to a website or a picture with the parts on a weighing scale). Also I do not know if the Pfadt seat mounts are still available.
Unfortunately I haven't weighed the seat mounts of my Recaro Pole Positions, but I guess that they are lighter than OEM as well.
If someone can chime in - also about other brands that are safe to use - please do!

gmkillr

Ok, 15-20 lbs is more in line with what I was thinking. 40 lbs for just seat mounts sounded really high.

The Pfadt mounts are no longer available though correct?

silvrhand

Yes and no, remember the futher your weight is from the outside of the rim the worse impact it has. If you go with a lightweight tired that sheds 4-5 lbs per tire you would likely notice it.

0Anthony @ LGMotorsports

Depends on the car, depends on the use, depends on the type of material the clutch is made of.

There are almost 45lb metallic clutches that I think are on-off switches and I have been in 18 lb carbon clutch cars that drove almost like stock.

There are a number of things to think about on this...not just weight but also the material of the clutch and the power/weight of the car.

A engine making 700 ft-lbs of torque at 2000 rpm can get away with a light clutch because it doesn't always need that kind of stored energy, but a stock LS1 with that kind of clutch doesn't have any power, nor stored energy to keep it moving so the car has a problem moving.

So I probably wouldn't use a 18lb Tilton clutch on a stock LS1 that I'm drag racing, and I also wouldn't use a 65lb ZR1 clutch to go road racing with

Vette @ 71

BTW some of us are real engineers. Heard of the calc. but it's a rather simplistic way of avoiding and discussing the true and measurable gains and benefits of weight loss.. No need to introduce theoretical anything. An earlier post had a theoretical gain of 75 Hp. It's a false prediction. Sign me up for that theoretical gain.

propain

I am sure ALL are real engineers thanks to google and the internet.

Well sometimes simple is better and way less boring.

Yes a 75 theoretical HP gain from 150lbs is ridiculous. I was trying to say otherwise but my math based on that hypothesis was somehow wrong even though as you pointed it there was no way to calculate it.


I understand what your getting at but really there are too many variables to come up with a precise calculation of how much ET a vehicle will gain by shedding weight. Its all a matter of where the weight is shed and how much. Then of course you introduce the environmental variables.

This is why the guess or theoretical calc was given. Yes its crude but its pretty close to what is to be expected. 100lb per 10th per MPH. Or PTW ratios on how much more HP you will need to net the same result. No need for an engineering degree.

gatti-man

There are plenty of solid mounts available. I didn't see the passanger mount being lighter than drivers which accounts for my error.

Pfadt mounts might be the lightest available but a solid mount is going to be light regardless.

Vette @ 71

Once worked with a purist in the Eng'g sense of the word and he was a rodder supreme. He developed a computer model for his rod. Taking into consideration actual wheel Tq. weight distribution on each wheel, calculated the Center of mass, and went so far as to make a mock up of his rod and took into one of our wind tunnels and calc it's drag, and also determined the coeff of friction at the wheels and likely other factors.

Using a baseline he then started dropping weight , various locations and tried to optimize a configuration for lowering his ET's.

I have not searched the World Wide web but I would not be surprised if similarly developed models exist, surely the professional racing world would have developed and use them before making expensive mod's

No Hp/Wt ratios for these guy's or back of the envelope calc's.

1 BAD BURB

fyi Allen, your car weighed 3050 with half tank of fuel. And its got Borla Stingers for exhaust.
I had it weighed a few months before I sold it to you...