Bus 4 spd trans, Anybody done this Options

[jwalters]

(IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

Thought of an interesting topic---has anybody put a beefed up bus or t1 trans in the teener----

I loved the gear spacing on my old superbug--and first gear for my car,,well,,,sucks ass--and second is too tall for a good start off--

Would rather spend 650 bucks on a pro-streeter WITH a rhino case and super diff than thousands upgrading my 901--

Sand rail mid engine cable shifter should be able to be adapted rather easily and the trans install is a non-event...

What you think???? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[jwalters]

QUOTE (andys @ Jan 22 2005, 12:58 AM)

What are each of the "net" ratios (1 thru 4 x final drive ratio)? I seem to recall that you can't get a tall enough 4th/R&P combo, as most applications are either for very tall tires and/or drag race applications. Can you point me to info on available ratio's that would perhaps suit higher HP motors? You will need about a 3.00:1 "net" ratio or better. The 901 is 3.14:1, a 915 is 2.94:1, and a 944T (016R) is 2.80:1..........Thanks, Andy

(IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) The true net ratio of any trans is 1:1-however, none are made to this standard, therre would be no torque mulitplication-I believe you are referring to the first gear ratio in the tranny minus the final drive, if not, clarify. Also- the manufacturer net is subjective--it depends on the entire setup from the factory to include final drive ratio and factory specified tire diameter..again--TIRE DIAMETER as soon as you take off those 165-15's, the net is no longer as advertised by the factory. It changes to correspond with the new diameter.

The overall net ratio is highly dependant on engine produced TORQUE--not HP --torque wins this equation, because that is what the factory finalizes the ratio of torque multiplication. The factories with all the hard math still will try 100's of tire and cog combinations to match the INTENDED purpose of the vehicle-i.e. how much tq to make it do this....-as we all know the purpose of the 914 was not top speed, nor was it 0-60, it was just give it enough gear to get out of its own way--take a 85 hp 1.8l and bump it up to 150 with the commensurate rise in tq and those stock cogs are going to piss you off--that is if you had the knowledge to know better--and most people do not--I did not either till just about ten years ago until I picked up a book called "auto math" while in a bookstore getting some coffee and perusing the porsche pubs.

Truely enlightening read--all must go right now to the nearest barnes-and noble and buy one, it will astound you.

Top speed is more highly dependant on top rpm and the engines ability to redline in top gear--basically, if it does--then it needs more final drive or a cog change, or both. When you are able to attain top speed with the engine giving out at about 250 rpm below redline-you have a good final drive--the cogs are what get you to this level--it is a very involved process, one of which why top race teams will test for a week before race--it is to finalize final drive among other things.