spool compared to stock posi

[81camaro]

I run a 8.5 10 bolt in my 81 camaro. With stock axles and posi unit, richmond 4.10 gears. Ive been told going to a spool would help the car ET. ? Winter project is Moser axles and C clip eliminator kit. 1.52 60ft 11.04 @124 best so far

[Supershafts]

You'll lose weight in the driveline, so it should help, as would going to an AL shaft.

Driving it on the street will have some new driving technique though

[Horndog]

Not sure if the swap will lose enough weight to gain you much ET.
If this is a street/strip car, I'd go with a standard spool.

[Supershafts]

You very well can gain et, should get you damn close to a full tenth, there is a good diff between the weight of a spool and posi.

pounds lost in the driveline are equivalent to hundreds carried, non lightened spools are lighter than posi units

[Speedbump]

IMO...the FIRST thing to do is to video your car on launch and see if either tire is spinning on launch.(do the shoe polish trick on the sidewalls) If the posi is controlling your wheel spin the gains will be very small compared to the driving loss you will suffer driving a spool on the street. I agree with your axle upgrade just for safety sake. I've twisted stock axles in cars with spools and slicks(poor boy racing) and the abrupt turn is not so much fun. If the tires do spin on launch, I think you should spend your money on a good locker to go with your axles. A little more money but lots easier to drive on the street AND your et's will improve just like a spool....minus the weight differential as mentioned.

[MadBill]

Per this thread (misplaced in Engine Tech): viewtopic.php?f=1&t=28625&start=30 a spool causes tire 'fight' and binding and usually runs a tenth slower than a posi.

[Supershafts]

That is true, but if you need to correct the car, and if you're running different psi in tires, which people used to laugh when i said to run swaybars 25 years ago, took them another 18 yrs to understand why....

[bigjoe1]

I have NEVER seen a spool run as fast or faster than a posi== In fact, every time a guy puts a spool in place of a posi, the car SLOWS DOWN, usually by a full tenth of a second I have seen the same results over twenty times.


JOE SHERMAN RACING ENGINES

[af2]

Tire run out is hardly ever measured and that would explain the 1/10 in E.T. I have seen over an inch trying to help with launch problems.

[MadBill]

If you've ever tried to push a spool-equipped car on foot, the issue is obvious. One guy can do it on the straight and level; it takes four to turn a corner..

[Speedbump]

I find this interesting in that my mind thinks there should be a line on bigger HP cars where the posi's inability to control wheel spin would give the spool an edge. Being acceleration is a squared function, better 60' by a little translates into more at the finish....or am I missing something? Joe, I'm guessing you run some pretty big HP cars. Do you use posi in all of them? Is there a line for posi's. I'm not talking about lockers. In my mind a posi is a clutch/friction type device.

[bigjoe1]

Dont get me wrong. You have to use the spool in fast cars, if for no other reason, for safety alone. but what I am telling everyone is very true. I do not try to explain WHY it is true, but I have seen it so many times, I just know it is true.. Another interesting point is when you put the 9 inch Ford rear end under a car that was built with something else, IT WILL ALWAYS SLOW down. When I ran my old Chevelle ( Mean Green ) years ago, I used the Moroso brute strength posi with aftermarket axles and it was very fast for its day ( 9.59 at 143.25 ) in 1973, and only had 815 horsepower. Now days, big Chevelles like that are MUCH SLOWER, because they have all the new TRICK STUFF under them--Go figure


JOE SHERMAN RACING ENGINES

[Speedbump]

Great info. In my budget, a 9.50's car is pretty fast. If it was a ladder bar or 4 link car, did you have to spend much time getting the chassis pre load set to give the posi a chance to work and have the car launch straight or was that unit that good? Was it trans brake, foot brake or manual?

[bigjoe1]

There were NO trans brakes in those day. foot brake at 22-2300 RPM== It was a 1970 Chevelle with all stock suspension except I had the first ever No Hop bars, that my friend Jim Thomas had just come out with. I ran stock shocks on the rear end, but I drilled a small hole into them and removed all the hyd oil, so they did NOTHING AT ALL. I ran one station wagon rear spring on the passenger side only, to pre load the chassis. I did have a loose converter ( they called it a 5500 stall), but it would flash up to 6000-6200 on the leave. I reved the engine to 78-8000 RPM. it was a 468 with a tunnel ram and two 1050 dominators. I had stock fenerwells, so the biggest tires I could run were 11.5 by 29.5 Firestone slicks.The car was so stock, no one could believe it. I used to come back into the pits and there would be two or three guys laying under the car looking for what made it so fast


JOE SHERMAN RACING ENGINES

[bigjoe1]

I forgot== It was a turbo 400 with a B & M converter= I ran different air pressure in the rear slicks to make it leave straight off the line


JOE SHERMAN RACING