Author Topic: trans output and pinion question  (Read 2787 times)

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Offline JimL

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trans output and pinion question
« on: September 07, 2008, 01:18:37 AM »
Working on another modified roadster (rear engine this time) and trying to puzzle the output shaft speed.  My engine makes it's power from 7000-9200, and my trans choices have 18-20% overdrive (could have 11,000 rpm pinion speed).  Has anyone had experience pumping lube to the extension housing bushing on the trans, and/or the pinion bearings on the diff? 

I ran the old 797 roadster at 9000 RPM on the pinion gear, in 1998, but it's trans had a roller bearing on the output flange (and I was still on short course in those days).  I don't have that option with my parts on hand (and the car will need to go long eventually).

Thanks for any advice/experience!

Regards, JimL

Offline Roadsters.com

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Re: trans output and pinion question
« Reply #1 on: September 07, 2008, 01:29:02 AM »
Any chance you could use a taller final drive ratio to keep the U-joint and driveshaft RPMs down and eliminate the parasitic power loss of the overdrive?

Dave
http://www.roadsters.com/

Offline JimL

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Re: trans output and pinion question
« Reply #2 on: September 07, 2008, 01:45:35 AM »
I'm using a 3.08 which is the tallest gear I can get for my axle.  I'm trying to get by with 24-26" tires, instead of the typical 28", because of the aero drag.  It's a puzzle....get the gears closer together for the smaller engines, and you're stuck with OD friction losses.  Find an axle tall enough....and smaller engines won't pull the gear splits (unless your wallet is thick and you can buy real race transmissions....I can sit on my wallet, most days, without discomfort).

thanks, JimL

Offline Roadster943

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Re: trans output and pinion question
« Reply #3 on: September 07, 2008, 10:04:46 AM »

  I read a interview on this site about the Wilson and Waters roadster. They run a Super T10 and had problems with the tailshaft bushing. They said they fixed it by putting a grease Zerk in it and the occasional shot of grease. That is about as easy on your wallet as it can get.  Vince
Land Speed Racing, The sheer joy of spending every dime you've got racing for nothing but glory. David Freiburger

Offline doug odom

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Re: trans output and pinion question
« Reply #4 on: September 07, 2008, 12:10:13 PM »
What trans are you using?
Doug Odom in big ditch

How old would you be now if you didn't know how old you are?
If you can't race it or take it to bed - it ain't worth having.

Offline JimL

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Re: trans output and pinion question
« Reply #5 on: September 07, 2008, 09:44:05 PM »
Doug...I have an R154 (the old 87 Supra Turbo 5-speed) or a Tacoma 6-speed (which has great first 5 gears and a shorter overdrive than the R154).  The R154 has an old Tacoma bell housing, so it bolts right onto my little V6.  The 6 speed is "homemade adaptor" time.

Thanks to Roadster943 for the tip.  I'll take a look at that....maybe I need the old floor button from a Packard (the one that shot grease to undercarriage parts by stepping on it!)  That might not fly in tech...whaddya think?!

Regards, JimL

Offline doug odom

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Re: trans output and pinion question
« Reply #6 on: September 07, 2008, 10:44:02 PM »
I have zero knowledge about that trans.  Sorry.
Doug Odom in big ditch

How old would you be now if you didn't know how old you are?
If you can't race it or take it to bed - it ain't worth having.