Rear end efficiency

[racergeo]

       John Burk get that streamliner done, so I can see it in person!!!   George

[Wide Open]

I am thinking about using a 7.5" S-10 or Firebird rear.  How much HP can these things handle? 

[SPARKY]

I am running 900 + with AT 400  and 2200# on the rear tires  -- no torque converter

[floydjer]

Strange Eng,. makes a 9 in.center section that uses 12  bolt Chev. gears. Gives you closer centerlines and the easy gear change.

[SPARKY]

Chevy 12 bolt had a 2.29 available that is virtually impossible to find

[Wide Open]

I am running 900 + with AT 400  and 2200# on the rear tires  -- no torque converter

You are running 900+ HP through a 7.5" rear?  What mods?

[SPARKY]

none, I run it with a series 2 torsen diff that I picked up of Ebay for $ 35 - 100.

[oldracer19]

I'm running a 9" Ford because of availability of gear (2.50) and strength. But, an 8" Ford is just as strong.  Nothing common below 3.00 for ratio though. 8" were common in the 69 Mustangs and up through the early 80's.

[Dan Parker]

  I have one comment and one question..

 1. The ford 8.8 is great stuff,strong,cheap,plentiful,efficient and I have a friend that says a 2.55 is available..I know 2.73's and 3.08's are everywhere.

  2. question??? How efficient is a quick change?? I will be starting a bellytank soon and the partner wants a quickchange. Amy downsides to this??  Thanks for any input. Dan

[SPARKY]

I have "heard" they are 2-4 percent less efficient and based on whichever other than a GM---total 5-7 less total efficiency. This is based on my best WAG    interpolation on various articles I have read.

the ford 8.8 is basically the  GM 10-12 or the (Chevy 12 which is slightly different)

Mark Williams coupler for the Ford 8.8 works on my caddy 10-12.  The 10-12 has a 2.28 gear.

ymmv

[jdincau]

Lots of people tell you that a quick change uses up too much horsepower. According to these sources a Hypoid (most popular third members) gear set is 92 to 96 percent efficient at power transmission. A spiral bevel (V-8 quick change) gear set and a single spur gear set are both 99 percent efficient. That makes a V-8 quick change 98.01 percent efficient. Tell me again why I should dump my quick change.


 http://www.zakgear.com/Hypoid_worm.html

http://www.roymech.co.uk/Useful_Tables/Drive/Gear_Efficiency.html

[SPARKY]

Jim, which base ring gear set is your V-8 QC based on?

[jdincau]

Sparky,
     It is a Halibrand, they were based on the 32-48 Ford ring and pinion. That's why they called it a V-8 as opposed to the older model A quick change which had no bearing on the pinion snout. The pinion is centered on the ring gear. Mind you I wouldn't want to push more than 600 HP through it. The later champ car quick change is based on a late 40's Ford truck rear end also having the pinion centered on the ring gear will take up to 800 HP. I have no Idea which ring and pinion the later Winters and Speedway types use.
Jim

[maguromic]

Dan, I think you need to look at the whole drive train for efficiency.  Depending on what you are running for a transmission you have losses there as well.  A Liberty will be more efficient than a Top Loader or Muncie and there is a study out there that claims the new pro stock Jerico is more efficient than the Liberty.  But if I were building a Lakester I would look at an early Weismann transaxle out of an Indy car or F5000 car.  They use a 12-bolt ring and pinion and you could put some monster power to it.  The one Al Teague used in his streamliner had been modified to run with a straight axle.  Tony

[SPARKY]

Jim, your bevel and quick change and a GM hypoid are probably very close to a wash. --