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Offy torque numbers 1972-1973


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#1 turbopanzer

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Posted 24 October 2014 - 08:37

Hi everyone

 

We know that the 159ci offenhauser engines had about 1200 hp in qualifying trim in 1972 and 1973. Never found anything about the torque. Does someone have some info?


Edited by turbopanzer, 24 October 2014 - 21:21.


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#2 Magoo

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Posted 25 October 2014 - 02:43

Historical output numbers are notoriously suspect. For that reason I like Karl Ludvigsen's book, Classic Racing Engines, which hews to reliable figures on the conservative side.

 

His official example of the turbo Offy is a 1970 version with 102.4 mm bore x 79.4 mm stroke, 2616 cc displacement, 8.5:1 CR, 2.66 atmospheres manifold pressure 

 

727 hp at 8250 rpm

510 lb ft 7000 rpm 

 

But that said, in 1973 at McLaren Performance in Detroit, on a real dyno using honest test procedures, an Offy on 37.5 lbs boost made 650 lb-ft at 7600 rpm and 959 hp at 8,000 rpm. Ludvigsen also reported these results in his book.  



#3 bigleagueslider

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Posted 26 October 2014 - 04:38

I know a couple of the guys that were involved with the Drake/Offy engines during the late 60s and early 70s. One of them, Stuart VanDyne, still has a shop just down the street from where I live. While the basic design of the Offy engine was pretty sound, I can't vouch for those 900hp+ numbers claimed.



#4 Lee Nicolle

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Posted 26 October 2014 - 23:01

I was going to say PLENTY. Though how much of that was actually useable is probably a different story. Yet alone how many they used for 500 mile races. 

Still very impressive figures though.



#5 Magoo

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Posted 27 October 2014 - 02:43

Yep. It's not a question of whether these fabulous numbers like 1200 hp are real, more what they mean. With unregulated boost, the Offys ran in and through the range of incipient knock, rattling along until they finally torched a ring land and went blooey, etc. How much boost can it handle? A dyno pull is one thing; a four lap qualifying run is another thing, and 500 miles is another thing altogether. Flash dyno readings against a manually operated brake aren't terribly meaningful or repeatable, and the output would be at or beyond the rated capacity of most dynos of the time anyway. Pick a number and turn The Screw you could probably get it to show on the meter for a moment or two. 

 

Then you have the problem of what you would do with the power if you had it. In this era -- I am not making this up -- these cars would jump sideways in the short chutes when the throttle was cracked . At 175 mph. Crude constant-flow mechanical fuel injection with zero driveability and massive turbo lag, no downforce or even aero balance, crap tires, etc etc. etc. It was something to see, for sure. 



#6 mariner

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Posted 27 October 2014 - 04:10

A few years back I had the pleasure of meeting Al Unser at his museum. There he was greeting guests with an amazing charm and humility given his acheivements.

 

He showed me the collection of Indy engines including the turbo Offy. His eyes lit up describing the kick in the back he got as he accelerated out of the Indy turns.

 

So I guess if it gave a four time Indy 500 winner a thrill it must have had enough torque!

 

As I said I;m in Albuquerque again and I went back to the museum. Please see it if you can , its superb and the Unser family trophy room is quite a sight, endless rows of trophies over 50 years of car racing.


Edited by mariner, 27 October 2014 - 04:10.


#7 ray b

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Posted 28 October 2014 - 20:20

METH PLUS WHAT WAS LEGAL ?

 

those are not gas motors

and nitro for Q was claimed too

 

but the F-1 hi-boost years did not use what we call gas ether