REAR ENDS - OPEN, SPOOL or LOCKER??

[836dstr]

Hey Sum,

My daily driver is a '57 Chevy 210 with a 327, 700R4 and a 3.70 gear. Freeway speeds @ 2,000 RPM but with the steep first gear accelerates pretty good and gets about 18 MPG.

I have an alum. head 383 on an engine stand but with gas prices what they are I may leave it there a while.

Tom

[Sumner]

Hey Sum,

My daily driver is a '57 Chevy 210 with a 327, 700R4 and a 3.70 gear. Freeway speeds @ 2,000 RPM but with the steep first gear accelerates pretty good and gets about 18 MPG.

I have an alum. head 383 on an engine stand but with gas prices what they are I may leave it there a while.

Tom

My motor has been a mild 290 HP or so 350 with 3.50 gears, 28 inch tires, 700R4 and Q-jet and I've been getting right at 20 without the teardrop and 16 with it running 75.  In the process right now of putting the new motor in with AFR heads and a bunch of good stuff so that I can turbo it next winter.  I hope I don't totally kill my gas mileage.

It will have the carb until next winter then I'm going EFI,

Sum

[836dstr]

Same topic in "Steering - Suspension - Rear End" above.

Same conclusions.

Jon could these 2 threads be merged?

Tom

[SPARKY]

Tom,  We "moved" it to Rear ends just so the research might go better---just trying to "make" FOURM work better---sorry for the confusion---next time will try to eliminate the confusion

[doug odom]

John, FWD with a spool would take a braver person than I to drive. If a CV joint or half shaft has a problem the drive will have a real big problem. I believe that is what got Dean Johnson upside down a few years ago.
Doug Odom in big ditch

[Roadsters.com]

After just reading this thread for the first time, I noticed that there was no mention of making sure that both of your back tires have the same circumference when you're using a spool. It makes running in a straight line a lot easier.

Dave
http://www.roadsters.com/

[JimL]

Just a note for FWD .... if you run extra "negative" scrub radius (get the contact patch well inboard of the kingpin) you'll get a counter turn effect should an axle break, or even loss of traction on the opposite side.  The drive on the wheel with traction tries to turn the wheel in the opposite direction of the "cross pull" from opposite side traction loss.

The import drag guys started using this in the late 90's and it did help keep some cars off the walls.  They also saw improvement in tracking as the front track became narrower (limited by turning clearance at the end of the crankshaft or trans case).  It's a tricky job on many front ends, because you have to convert from strut to double a-arm and the spindles may have to be fabricated from scratch (to reach far enough inside the front wheels for extreme scrub offset).

I also have a question about live axles, if anyone has an idea.  Does the long axle provide less torque, than the short axle, on a typical rear end?  I know from my air tools that every bit of extension takes away available torque at the socket.  I suppose it's not enough to matter...but I sure don't know the answer.

Thanks!
JimL

[jacksoni]

I echo the tire deal as well. I was running a mini-spool with Mickey Thompson bonneville tires and was straight and easy to drive. Looking for some more, switched to  sl taller front runners, same pressure and it was definite squirrelly and needed to drive it, not just point and stab the  throttle.  My engine makes maybe 130 tq at the wheels so wheel spin not such a big deal. Maybe a higher pressure would have helped.

[SPARKY]

JimL the longer shaft just has more torsion spring to absorb the impacts trip hammer shocks---the counter force of the drive shaft rotation is the force that gives the right rear tire on a car less traction than; the longer axel will help tractive effort---ie the longer lever resisting the effort to pick up the tire   I THINK

[JimL]

Thanks for the thinkin', Sparky, I'm puzzling the engine location for my roadster, today.  The pinion on the diff is offset to the right (axle shafts are equal length), so I have to offset the engine/trans to keep the driveshaft pretty straight.  The driveshaft is only gonna' have about an 8-10" tube, so I think I'm stuck with positioning "stuff" to get the car balanced.

After reading the posts about tire sizing and corner weights, I'm going to have to be much more careful.  The engine if HEAVY in this project.  Hopefully I can juggle batteries and ballast and make everything come out right.

I really appreciate all the notes passed along from the long-time builders.  How in the WORLD did we get along without the internet?

Regards, JimL

[jimmy six]

Doug, If I'm not mistaken I believe "part" of Dean's CV joint problem was lack of maintenance. It was quite apparent when we loaded it in his trailer prior to leaveing the salt at the end of the meet. CV joints in off road have looked to be pretty good with the abuse I see they get in the 4 wheel drive class. Good luck.........JD

[racergeo]

       John Romero, any conclusion on front wheel drive with spool? My FWD lakester moved around alot at SW and I concluded that it was salt condition in combination with my me not having enough balast on the front. Last year with a C engine had no wheel spin in low, but this year they would spin like crazy unless I pedaled it. I have a B engine and didn't ad any balast cause I was just trying to go 'just" 5 mph faster. I think I went over the edge. Any thoughts as I have a spool also.

[SPARKY]

What is your scrub radius?

[racergeo]

  Scrub radius is right at 3/8". Car went fairly straight last Oct. but have added some Tq and HP. I'm thinking wheel spin was moving car around and as I corrected it the caster would load the tires unevenly and create further problems. I plan on putting in about 400#s of lead in front and put my car on electronic wheel alignment equip. to be sure every thing is pointed sraight. I read about rear tow in. May be something to look into. Still thinking it is wheel spin. How much wieght did you ad to rear Sparky?

[Glen]

Several articles on scrub radius on google