About how much difference is there in weight in the steel drive shaft and the Al ones, mainly the later LS1 drive shafts?

 

if i remember correctly, stock steel one is like 12 lbs and the alum. ones are about 7 lbs. so, 5 lbs difference.

 

search in the drivetrain forum. It has a list somewhere of every alum driveshaft, its weight, plus the weight of a v8 steel driveshaft.

I've come to decision if I can find one for less then 100, get it. I'm not going to pay more then that for one.

 

yeah, i'm in the same boat as you. people want 150 to 200 american for them and its not worth it to me

 

16 lbs - Stock steel LT1 driveshaft
12.2 lbs - 3rd gen aluminum 1LE driveshaft
12 lbs - LPE aluminum driveshaft
11.5 lbs - Stock aluminum LS1 driveshaft
10 lbs - RK Sport aluminum 1pc driveshaft
4 lbs - ACPT carbon fiber

 

I want to elobarote on this usefullness of the lighter driveshaft. And most importantly why the few of you here have not experienced much of a difference in feel.

First of the driveshaft is part of the drivetrain and attributes to HP loss through drivetrain to the rear wheels. This is the difference between "flywheel" and "rearwheel" HP ratings.

Just about everyone of you here have heard the "so called" specs of auto lossing 20% and manuals lossing 15%. For the most part, this is a basic rule of thumb but is not particularly always the case when comparing you car to someone elses.
Granted, in the same car, a stock manual will have less drag than a stock auto with all other factors remaining the same.

Now the 15 & 20% losses to the rear wheels are not the total result of the tranmissions! It is a combined loss of the clutch/ convertor, the gears and pump (sticks don't have a pump, hence their more efficiant), rotation weight of the entire drivetrain, and rearend gears. All of this combined is what makes up the aprox 15% in manuals and the aprox 20% in autos.

My car (being auto still) has less loss than any stock V6 manual drivetrain because of weight even though it is an auto. Now if I were to put a stick into my car, yes it would be even better (less loss).

Now to the driveshaft. That 4 lb decrease you are getting from the steel to the alum driveshafts may only show a net gain of 2hp to the rear wheels on a car that puts out 135 FWHP but more like a 4hp gain on a car that astwice that HP. The more HP the more it will show a gain.

As the speeds build, the shaft will spin easier with less vibration and will allow the car to build higher rpms more freely. This gain builds with the faster the vehicle is traveling.

With all things equal, A 16lb steel shaft may give a stock car like ours 100 RWhp when a 4lb CF driveshaft (and other factors I have done to the auto and convertor) will give about 110 hp. It is 1/4 the rotaion mass and robs less power, thus delivering more FWhp to RWhp than the heavier steel unit.

Our cars just aren't powerful enopugh to feel the difference from a 16lb to a 12 lb driveshaft change. The higher HP cars will feel this a little better than we will.

My car stock should have been putting out aprx 108 RWHP. I fingure right now its in the range of 135-140 RWHP with the built auto trans convertor and driveshaft + the added engine HP. I am expecting about 204-212 RWHP range with the new motor I am building.

 

Did you mean sticks?

 

Yes, Ill fix it. Thanks CJ.

 

Damn! Now my quote looks like I pulled it out of thin air.

 

na, deans good at admiting if he makes a mistake and corrects it. We know this

 

So how do you go about getting as little parasitic loss as possible? AL driveshaft, and what else? Is there anything else in the rear to loose weight?

 

Its nice to have all that info in one place. Thanks for the post vsixtoy

 

fbody, you want the least weight? Get the CF driveshaft as dean has, plus aluminum drums.

 

How much is that carbon fiber drive shaft?
Where do you get it?

 

In my case with an Auto trans, Jimmy built it as lightweight internally as possible without compromising integrity. He kept the 4 plantary gear setup but it is and aftermarket one (My truck trans has the heavier and stronger 5 plantary setup) 10 vane pump (truck has the 13vane, stock is 7 vane) but raised the boost valve to a .521 and blocked off the accumulator valve to raise pressure I guess. He told me a few times what he did but this crap is a foriegn language to me- I leave it to the experts.

Everything inside is completely optimum and aftermarket for the amount of power I am am expecting (which equvilantly is not very much at all compared to what he would build trannies for all out drag cars.) This was not a stock tranny that was upgraded, but rather he took a V6 case and fitted it with entirely all brand new and trick aftermarket goodies and everything was focused on rotation mass, but yet strong enough also to withstand abuse of a 3000lb car with 300 HP daily (the truck tranny will handle 800HP). This was probably about a $3500 trans/convertor combo if I had it custom made retail. Jimmy was a friend, unfortunately, he has fallen on hard times and ended doing a bad deal (screwed a close friend of mine) within the last year that ruined my opinion of him. Last I heard, he isn't even in business anymore.

The convertor is the whole key to the equation. He had one custom made for me with a lightweight exotic 9" housing and internals. It is a one-off convertor that I will have to have duplicated the day it goes out.

The rearend is basically left stock configuration with the lightweight axles in it- this will last forever in a V6. New bearings and a Roadrace Version Auburn posi puts the power down. I opted to go down to 3.23 gears which loose torque slightly but I offset that by using lightweight racing gears. They will wear faster and I will have to replace them sooner, but again its a lightweight V6 and not putting out monster power. The brakes I did go to disc but I when to thinner yet larger 12.2x.81 rotors that are in fact 2pc with a lightweight hub. These have about the same rotation mass as drum brakes, They are much lighter than the original 10.5 iron discs.

I have done alot to this car that goes unnoted unless I really detail it- I have just always stated that it has a lightweight drivetrain and have never really detailed it for others to ponder.
I have mentioned in the past and will state again that this thing shifts up and down immediately as if it were a pheumatic shifter. No lag at all in between gears. This is not like your typical over-the-counter B&M streetfighter tranny either- it is much better responsive. I have driven on plenty of so called aftermarket 700r4's, they are decent, but not like this unit, This car is so fun to drive because of the way it shifts. It does not hammer into gear like the truck, yet it is quicker and smoother, yet positive. Its a spontanious shift without the neck jarring action. The truck is much more HD and slams into gear like a Full Drag tranny (because it is). Jimmy nailed this one in the Camaro for me.

 

you mentioned the rear brakes. i have considered switching to discs on the rear but i am wondering (i think you answered it, dean) which is heavier, the drums or discs? apparently the stock disc setup is heavier than stock drums? how much of a difference is there between the two? i haven't looked too far into brakes yet so i'll just ask here...what all is available as far as lightweight brakes go on these cars? how much better are the aluminum drums over the steel/iron ones? i'm not too worried about 'upgrading' my brake system as it performs quite nicely but i would like to lose some weight throughout all of the 'rotating mass areas.'