Landracing Forum

Tech Information => Steering - Suspension - Rear End => Topic started by: iskipnw on January 10, 2010, 08:57:58 PM

Title: Ford 9 Inch 3rd Member
Post by: iskipnw on January 10, 2010, 08:57:58 PM
I am interested in hearing what type of 9 inch full floater 3rd member people run on the salt, and why. 
My application will be roadster class automobile. 
There is much to understand about Spool, Detroit Locker, spider, etc.  Thanks
Ken
Title: Re: Ford 9 Inch 3rd Member
Post by: Stainless1 on January 10, 2010, 10:02:02 PM
A lot of discussing on that is in the archives... I don't have a roadster but the big car has a spool and the little car is solid axle chain drive so a lot like a spool.  You will find there is no right answer.  One of the best pieces of rear end advice I've seen here is if you run a spool and spin, put in a locker... if you run a locker and spin, put in a spool.... think it was JD Tone
Good luck and keep reading, there is no easy answer.
Title: Re: Ford 9 Inch 3rd Member
Post by: desotoman on January 10, 2010, 10:30:21 PM
Stainless,

Just a reminder, don't forget open.

Tom G.
Title: Re: Ford 9 Inch 3rd Member
Post by: Stainless1 on January 10, 2010, 10:38:40 PM
Tom, aren't those the ones that are hard to keep the oil in....  :roll:  as opposed to the closed ones....  :|
I forgot, the bike has a spool as well, so that is the one I recommend....  :-P
 :cheers:
Title: Re: Ford 9 Inch 3rd Member
Post by: desotoman on January 10, 2010, 10:52:35 PM
Yep,

Freud told me to always keep them lubed up, and I would not have any problems. That is my story and I'm sticking to it.

Tom G.
Title: Re: Ford 9 Inch 3rd Member
Post by: jimmy six on January 11, 2010, 11:58:14 AM
Stainless was a little off...If you have any device which drives both rear tires and you spin, put in an open rear...and in contrast if it's open and you spin, change it to something which drives both.

If you are considering a high HP roadster spinning is not an option but an enevitability. It just seems to be that way. At 160 MPH and 300+ HP, I never even gave spinning a thought. At 700HP and 185 and the same weight car it became an eye opener. I choose not to change the rear end but to lengthen the wheelbase 1/8" in the direction of the spin and completed the meet without problems. The following year we added 600# and went 195+ with no problem. Ended up over 216 and spinning never reoccured but learning to drive a car that ran out of HP for a mile was an unforgetable experience.

Long pointed cars have different traits than anything with a verticle grille shell and 2 open tires leading the way.........Good Luck JD

PS: I still like to drive our roadster more that anything else and we will be back in October at WF
Title: Re: Ford 9 Inch 3rd Member
Post by: Rick Byrnes on January 11, 2010, 12:51:41 PM
What JD said!
Although I will add that I started with a spool which turned out to be a good choice for me.
Title: Re: Ford 9 Inch 3rd Member
Post by: Stan Back on January 11, 2010, 02:32:57 PM
With the lightest weight in our class (2800 lbs.), we've set the record 4 times  in 7 years -- 3 times over 200.  No ballast, but a heavy frame.  Ran a positraction one run -- spun for the first and only time.  Open for us.
Title: Re: Ford 9 Inch 3rd Member
Post by: John Burk on January 11, 2010, 11:38:39 PM
Have any roadsters used IRS ? Seems like it would be easier to drive with consistently rear wheel loading . Do Corvettes spin less ?
Title: Re: Ford 9 Inch 3rd Member
Post by: Stan Back on January 12, 2010, 12:09:22 PM
Our roadster now has IRS -- Isn't Really Suspended.  I guess what works for one, may not for others.  Seems to me I've seen Corvettes with 9" in them.
Title: Re: Ford 9 Inch 3rd Member
Post by: 4-barrel Mike on January 12, 2010, 01:19:44 PM
A roadster toad would say that a Corvette is NOT a roadster.  :mrgreen:

Mike
Title: Re: Ford 9 Inch 3rd Member
Post by: Wide Open on February 26, 2010, 09:06:04 AM
Long pointed cars have different traits than anything with a verticle grille shell and 2 open tires leading the way.........Good Luck JD
Can you explain the difference? 
Title: Re: Ford 9 Inch 3rd Member
Post by: SPARKY on February 26, 2010, 09:09:54 AM
center of pressure  :?
Title: Re: Ford 9 Inch 3rd Member
Post by: RichFox on February 26, 2010, 12:14:51 PM
Have any roadsters used IRS ? Seems like it would be easier to drive with consistently rear wheel loading . Do Corvettes spin less ?
I believe that when I looked at the Hofman-Markley roadster it had a Corvette IRS. My roadster has swing axle rear as did the old Markley roadster I believe.