Will have a Posi over a Pegleg actually make me "faster"?

[TIMSPEED]

I'm thinking about taking my truck to the track to see what it'd run. Now, here's the thing, I could CARE LESS about what my E.T. is, all I'm concerned about is my MPH. With a 3.73 posi would my MPH be different, than having my 4.10 pegleg. (We're assuming same tires, no drag radials, just plain Kumho 255/55 17's)

[Captkaos]

Yes.

[TIMSPEED]

How MUCH different? 1-2mph or like 3-5?

[1FaastC10]

Tim, lets put it this way... the pegleg puts the power to the wheels with the least traction. a posi or LSD device will put the power to the one with the most traction. traction = forward movement. the more traction you can get, the faster it will be.

[N2TRUX]

Originally posted by TIMSPEED
... Now, here's the thing, I could CARE LESS about what my E.T. is, all I'm concerned about is my MPH. ...

I have to know WHY? If all your concerned about is mph, back up way behind the line and get a running start. I have never heard anyone say they don't care about e.t.

[ocbaud]

Originally posted by N2TRUX
I have to know WHY? If all your concerned about is mph, back up way behind the line and get a running start. I have never heard anyone say they don't care about e.t.

yeah, if he wants mph, he should jump on the highway with some 2.73 gears and a 700r4:p

[rockman20]

4.10 peg leg? That thing must just BBQ that rear tire!

Switching to posi will let you get out of the hole quicker since power is being sent to both wheels instead of just the one that spins the easiest. Even though you will be losing some gearing, I would say it should make you faster. Not sure by how much, but I live by what my old auto teacher told me once.

"Spinning your tires is not impressive. Anyone can create a cloud of tire smoke. But tire smoke does not make your car fast. If you think it does, I will make you a bet. 20 bucks says your car is not fast. How we determine this is I will get in the car with you and tape your 20 to the dash in front of me. You mash the gas and if I can not reach forward and get that 20 off the dash, then you have a fast car."

[1FaastC10]

a spool would put power to both wheels, any other traction device should just put it to the wheel with the most traction.

[TIMSPEED]

Originally posted by 1FaastC10
a spool would put power to both wheels

But:
Spool + Turns = SNAP!!

[1FaastC10]

nah, not if you buy a good one. good luck finding one for your 12 bolt though.

[79BIG10]

Originally posted by TIMSPEED

But:
Spool + Turns = SNAP!!

Get a lockrite or power trax locker. It divides power to both wheels and comes unlocked when you turn. Plus you can install it yourself without resetting the gears.

[CT-Truckster]

only if you have enough power to make use of it.

[rockman20]

Sorry if I am naive here, but here is how I thought a posi worked. Inside it has a set of clutches inside. When you mash on the throttle, the spider gears push the axle side gears out which compresses the clutch plates and provides power to both rear wheels. Not just the one with traction.

However, to prove that it does not provide power to the tire with traction, you can get stuck with a posi unit. Stop with one tire on ice and one on pavement. There is not enough force on the spider gears to push outwards on the axle gears so in this case, the tire with less traction gets the power.

Never seen a spool but have a basic concept of a Detroit Locker Here you have kind of the same idea except for instead of clutches it is kind of like a collar assembly. Springs force the two collars together which basically locks the rear end solid. If you go to take a corner, as long as you are not applying lots of power to the assembly, the collars are able to overcome the spring pressure and they pull apart giving you an open rear end again.

I would never use a spool on the street. If you wanted to go that route, bring your truck over. I will weld your gears together and you will have the same effect.

But I could be wrong here.

[TIMSPEED]

Originally posted by rockman20
But I could be wrong here.

Actually, you're dead RIGHT. A lot of honda guys that ONLY drag race there cars, will weld their axles together, to get the ultimate traction for CHEAP.

[Captkaos]

Originally posted by 1FaastC10
a spool would put power to both wheels, any other traction device should just put it to the wheel with the most traction.

A locking differential (detroit, lock-right..) LOCKS both axles together like a spool, UNTIL you turn and it "differentiate the power, or unlocks the inside wheel.

A limited slip has a set breakaway that both are locked until that breakaway torque is exceeded.

Spools AREN'T a differential, and are shouldn't be used on the street. Chevy rearend require a c-clip eliminator for their use, typically these aren't "approved" on a race track.

Reguardless, in actuality, locked or open isn't going to effect top speed as much as changing the gear ratio. It will effect your ET though. If you are talking about your ET top speed, then yeah it will change as you will be actually moving with a posi as opposed to spinning with an open. How much I don't care to guess as there are too many variables to consider, but if you swap from one to the other, you speed AND ET will change.