DeTomaso Mailing List: December 97, Message #99
     



From: 	Dennis Antenucci <itbewild@gte.net>

Subject: Ring Gears - Part II

Date: 	Mon, 8 Dec 1997 20:03:21 +0000



Yo People (Curt too!!),



Many years ago the car of my dreams was a Jag XKE or E-type. When I 

finally had enough bucks to buy one in 73 it was a 69 and I was 

disappoined to find out that the car was closer to 130 mph at red line  

then the 150 mph I had been reading about since 1961 in all the U.S. and 

U.K. mag's.  



After a little research I found out that the ring gears in the North 

American imports were geared a little lower then their European 

counterparts. So I got the higher gear option, built the engine and it 

still wouldn't do 150 mph BUT I was successful at blowing the engine!!! 

:-]



I later fond out Jaguar provided a heavily tweeked car to the 

early U.S. and U.K. testers with even higher gears that allowed it to 

nodge the 150mph mark which for 1961 was pretty gawd damn fast for it's 

day. To this day I can only think of one other car that left such an 

impression and as Andy Poling would say, "we know what that is don't 

you?" :-] But the Jag was my "first love" and you never forget those.    

 

Anyway, when we were at Willow Springs last month Bo Bo (Brock Tella) 

mentioned that he had never got much more then about 135 mph out of his 

Pantera!! That got me to thinking this last week and everyone who knows 

me knows I don't like to think too much.



So I talked to our ZF experts and I found out that the "early -1" ZF 

boxes were geared differently then the later ZF 5DS/2 boxes. The first 

gearbox, sometimes called the "close ratio" gearbox, was good for 

acceleration but bad for top end speed. If you run the early -1 box up to 

6000 rpm with 27" diameter tires and a 4.22 ring gear you'll probably 

only see 135 mph versus the 157.8 mph with the later -2 box.  Use a 

smaller diameter tire and you'll go even slower.  The gear ratio's 

compared as follows:



	-1 EARLY BOX		-2 LATE BOX

I GEAR		2.41			2.23

II GEAR 	1.47			1.47

III GEAR	1.13			1.04

IV GEAR 	0.958			0.846

V GEAR  	0.846			0.705



This might explain Brock's acceleration out of the corners but limited 

top end speeds. . .More to follow so stay tuned.

Mad Dog, IRA 		    

P.S. David do NOT go out and try this tonight! :-]