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IndyCar engine rules since 1909


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#1 HistoryFan

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Posted 17 February 2014 - 10:23

I cannot find many details about the engines used in IndyCar since 1909 (AAA, USAC, CART). The last last 20 years are well-known but what about the years before?

 

IndyCar had the first turbo engines in the 60s - before F1 goes to turbo.

 

Has anyone details about when the strongest engines were driven and how much hp they had?



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#2 Collombin

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Posted 17 February 2014 - 12:11

The first turbo engine to compete at Indy was back in 1952 actually.

Horsepower reached its summit in the early 1970s, at around 1,050 in qualifying trim from the turbo Offy I believe.

#3 HistoryFan

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Posted 17 February 2014 - 13:28

but that was a supercharger, a compressor, wasn't it?



#4 Collombin

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Posted 17 February 2014 - 13:39

It was definitely a turbocharger (this was the Cummins diesel of course). Admittedly I don't think any other turbos made the race until about 1966 though.

#5 HistoryFan

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Posted 17 February 2014 - 13:52

Okay thank you.



#6 D-Type

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Posted 17 February 2014 - 15:31

What has your research up to now found?  That is of course assuming you have done some basic research before coming here.

 

The Marmon Wasp's engine was a six- cylinder with the cylinder block cast in 2-cylinder units.

 

The Miller and the Winfield/Novi engines had centrifugal superchargers

 

I assume the Boyle Special (Maserati) had a conventional Rootes blower but I am not prepared to do your basic research for you.

 

A quick Google didn't turn up much on the engine in the Adams-Sparks that won in 1946 other than that it was supercharged.  It may have been a straight 6 but the site I found that on was none too clear.  Can anyone provide more details or a link to some information please? 


Edited by D-Type, 17 February 2014 - 15:41.


#7 Collombin

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Posted 17 February 2014 - 15:47

Twin Roots blowers on the Boyle Maserati I think.

The Sparks engine on the 1946 winner was indeed a supercharged 6 cylinder.

#8 Michael Ferner

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Posted 17 February 2014 - 17:55

There was no "IndyCar" racing in 1909, however you define the word, so it's a bit pointless discussing engine rules for that year. What has become known over time as IndyCar racing started in 1916, when the rules stipulated a maximum swept volume of 300 cubic inches, roughly 5 litres. Some of the engines developed 100 bhp and more. Engine capacity dropped successively over the following decade or so, but power output rose to about 150 bhp, and over 200 bhp with the use of superchargers. In 1930, the displacement limit was raised to 6 litres, but other restrictions meant that the cars were down to about 200 bhp again. The most powerful cars prior to WW2 ran in 1937, the last year of the 6-litre formula, when most of these restrictions had been lifted, and the Sparks (or: Sparks-Thorne) 6-cylinder entry that year easily developed more than 300, perhaps 350 bhp. From 1938 onwards, international Grand Prix rules prevailed.

 

After WW2, with unblown 4.5-litre engines, power output steadily rose again to about 350 bhp, and a slight reduction to 4.2 litres in 1957 didn't change that much: by the sixties, 400 bhp were available for most cars, and shortly thereafter supercharged and/or turbocharged 2.8-litre engines raised the benchmark even further. It's been said that some of the 1970s engines put out four-figure numbers, but difficult to say how much of that was available on the track. Bit by bit, horsepower was then ruled in by restrictions to the boost pressure, i.e. pop-off valves.


Edited by Michael Ferner, 17 February 2014 - 17:56.


#9 HistoryFan

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Posted 17 February 2014 - 18:21

Thank you.



#10 Eaglenindy

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Posted 18 February 2014 - 03:33

The spec's have been constantly changing over the over the past century.  In the 1910's it was 400+ cid (around 7 litres)

 

In the 20's it was 1.5 litres (91 cid) for DOHC racing engines and higher for pushrod motors

 

In the 30's/40's "Junk Era"  Offies and DOHC racing engines were around 270 CID (120? CID for superchargeed racing engines) and pushrod engines in the 300+ cid (5+ litre)

 

In the post war era 270 for DOHC's and there were  very few pushrods, in the 50's (Post LeMan's disaster) CID was lowered to 255 for N/A and 183 (3 litre for s/c)

 

In the post 55 era, n/a DOHC was 255 cid and 167 cid for s/c or turbo DOHC's.  Stockblock n/a went from 5 litre to 360 cid (5.7 litre)   Super/turbo charged pushrod engines 209 Cid.

 

Boost pressures veried from 74 on and in the early 90's USAC allowed "purpose built" pushrod V8's higher boost than the others, so the MercedesRex Ilmor 500i (1000+ hp) engine was born.

 

Since the birth of the IRL/Indycar series, no turbos until 2012 and engine volume was bouncing between 3 and 4 litres.  Now 1.6 litre 6 cylinder turbo motors with self imposed boost limits via electronic McLaren software.



#11 D-Type

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Posted 18 February 2014 - 09:32

There's a typo in there somewhere:

 

For DOHC engines  it was

1938-56:  4.5 litres (270 cid) unsupercharged / 3 litres (180cid) supercharged

1957-68:  4.2 litres (255 cid) unsupercharged / 2.8 litres (167 cid) supercharged

 

I don't know about the pushrod engines as my (Euro-centric) references don't mention them



#12 Michael Ferner

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Posted 18 February 2014 - 15:55

The spec's have been constantly changing over the over the past century.  In the 1910's it was 400+ cid (around 7 litres)

 

In the 20's it was 1.5 litres (91 cid) for DOHC racing engines and higher for pushrod motors

 

In the 30's/40's "Junk Era"  Offies and DOHC racing engines were around 270 CID (120? CID for superchargeed racing engines) and pushrod engines in the 300+ cid (5+ litre)

 

In the post war era 270 for DOHC's and there were  very few pushrods, in the 50's (Post LeMan's disaster) CID was lowered to 255 for N/A and 183 (3 litre for s/c)

 

In the post 55 era, n/a DOHC was 255 cid and 167 cid for s/c or turbo DOHC's.  Stockblock n/a went from 5 litre to 360 cid (5.7 litre)   Super/turbo charged pushrod engines 209 Cid.

 

Boost pressures veried from 74 on and in the early 90's USAC allowed "purpose built" pushrod V8's higher boost than the others, so the MercedesRex Ilmor 500i (1000+ hp) engine was born.

 

Since the birth of the IRL/Indycar series, no turbos until 2012 and engine volume was bouncing between 3 and 4 litres.  Now 1.6 litre 6 cylinder turbo motors with self imposed boost limits via electronic McLaren software.

 

I'm sorry, but this is a load of nonsense! Almost nothing of what you wrote is correct.