The Miller 91 Supercharged Front Drive “Perfect Circle” Indianapolis


That is the Miller 91 Supercharged Entrance Drive “Good Circle” Indianapolis, a rare car developed by Harry Miller – a person now extensively considered the best American race automobile designer of the twentieth century.

The Miller 91 is powered by a sophisticated double overhead cam inline-eight cylinder engine with a supercharger that’s able to 250 bhp at 8,000 rpm – astonishing figures by the requirements of the Nineteen Twenties.

Quick Details – The Miller 91 Entrance Drive

  • Harry Miller left faculty early and by no means obtained formal engineering coaching, regardless of this he grew to become probably the most influential and profitable American racing automobile and racing engine designers of the twentieth century.
  • Vehicles designed by Miller and his staff received the Indianapolis 500 10 instances, different vehicles that have been powered by Miller (or Miller-based Offenhauser) engines received the race one other 29 instances. On prime of that Miller vehicles received 43 Nationwide Championships.
  • The Miller 91 was developed from an nearly clean slate to fulfill the brand new 91.5 cubic inch (1.5 liter) engine displacement restrict for 1926. The straight-eight engine has DOHC, a supercharger, as much as 250 bhp at 8,000 rpm and each entrance and rear wheel drive variations have been constructed.
  • The front-wheel drive Miller 91 you see right here is powered by the 1927 AAA Nationwide Championship-winning 91 engine, and it could go on to win the Indianapolis 500 in 1930 with Billy Arnold on the wheel.

Harry Miller – An American Eccentric Genius

Griffith Borgeson referred to as Harry Miller “The best inventive determine within the historical past of the American racing automobile” – whereas that will initially look like hyperbole, the extra you find out about Miller the extra wise the quote turns into.

Image DescriptionAlong with his distinctive moustache Harry Miller was probably the most enduring characters within the automotive world of the Nineteen Twenties and Thirties.

Harry Miller was born Harold Arminius Miller in 1875 Menomonie, Wisconsin. He left faculty as quickly as he might and pursued his ardour for the model new world of vehicles. Inside a number of quick years he was dwelling in California working his personal carburetor manufacturing firm, and on this capability he developed various carburetor-related patents.

By the 1910s Miller’s store had expanded its operations to engaged on race vehicles, together with these constructed by Duesenberg and Peugeot. It was right here that he’s mentioned to have developed an intimate understanding of superior overhead cam engine design – one thing that may drastically affect his personal engine designs sooner or later.

Over the course of the 1910s and Nineteen Twenties Harry Miller would design various outstanding, race profitable engines working side-by-side with chief machinist Fred Offenhauser and gifted draughtsman Leo Goosen.

By the Nineteen Twenties Miller’s engines have been totally dominant in American racing, a lot in order that the foundations have been modified greater than as soon as within the hopes of giving different producers an opportunity to win, or no less than place within the prime 10.

As soon as such rule change occurred in 1926 when the engine displacement restrict was modified to 91.5 cubic inches or 1.5 liters. Miller developed a brand new straight-eight engine with double overhead cams, hemispherical combustion chambers, a supercharger, and all alloy development for low weight.

Miller 91 Race Car 10

Image DescriptionThe all-alloy engine developed for the Miller 91 is a straight-eight with double overhead cams, a supercharger, 250 bhp at 8,000 rpm and a prime pace of 171 mph.

This 1.5 engine was as intricate as any Swiss watch, early variations developed 150 bhp however later examples are mentioned to have exceeded 250 bhp at 8,000 rpm.

Miller-developed vehicles received the Indianapolis 500 a complete of 10 instances, different vehicles that have been powered by Miller (or Miller-based Offenhauser) engines received the race one other 29 instances on prime of that. Miller vehicles additionally received a complete of 43 Nationwide Championships.

Within the Thirties Miller partnered with an up and coming automotive designer named Preston Tucker. The 2 males labored collectively on Indianapolis 500 race vehicles and on an uncommon car referred to as the Tucker Fight Automotive that was supposed for navy use.

Miller died in 1943, forsaking a legacy that few in automotive historical past might ever hope to match – on both aspect of the Atlantic.

The Miller 91 “Entrance Drive”

The Miller 91 was designed from the outset to have each entrance and rear wheel drive variations. Miller was an enormous fan of entrance wheel drive as is allowed the automobile to be considerably decrease, as there was no driveshaft working beneath the driving force to the rear axle.

Miller 91 Race Car 7

Image DescriptionRight here you possibly can see the entrance differential on the entrance axle, within the entrance wheel drive variations of the Miller 91 the engine was basically put in backwards with the gearbox on the entrance.

He additionally believed that entrance wheel drive helped with excessive pace cornering on oval tracks and he might have been onto one thing, as his vehicles took the highest step on the rostrum on the Indianapolis 500 various instances.

The Miller 91 is fitted with a big rear gasoline tank straight behind the driving force, the seat is simply 18 inches huge so driver measurement and weight was a major issue, and each variations of the automobile had a entrance mounted 1.5 liter Miller straight-eight.

The entrance wheel drive model basically had the engine put in backwards, with the gearbox on the entrance sending energy into the entrance differential.

The few surviving examples of the Miller 91 at the moment are nearly all in museums, there’s one within the Smithsonian and one other within the Indianapolis Motor Speedway Corridor of Fame Museum. It’s exceedingly uncommon to see them come up on the market on the open market and after they do they sometimes change arms for the higher a part of $750,000 USD.

The Miller 91 “Good Circle” Proven Right here

The automobile you see here’s a vital Miller 91 for various causes, it was initially purchased by the legendary Pete DePaolo in 1927 who promptly received the 1927 AAA Nationwide Championship with it.

Miller 91 Race Car 11

Image DescriptionFor aerodynamics the Miller 91 was very slim, drivers needed to be beneath 18 inches huge or they merely wouldn’t match within the seat.

It was later offered on and modified to fulfill the brand new rules, together with the fitment of a brand new Miller 122 engine, bored out to 151 cubic inches. Billy Arnold drove this automobile to a win within the Indianapolis 500 in 1930 and received the Nationwide Championship with it in the identical 12 months.

The automobile suffered a few on observe mishaps requiring repairs nevertheless it was nonetheless racing at Indianapolis into the late Thirties, ending on the rostrum in third place in 1937. The automobile was retired in 1939 and its historical past might have ended there however for the truth that avid Miller collector and historian Chuck Davis acquired it.

Over a few years Davis was in a position to safe a slew of vital components for the automobile together with the unique engine as raced by DePaolo in 1927. The automobile has now been restored again to its 1927 specification and it’s now attributable to roll throughout the public sale block with RM Sotheby’s later in August with a worth information of $700,000 – $850,000 USD.

If you happen to’d prefer to learn extra about this Miller 91’s extraordinary historical past or register to bid you possibly can go to the itemizing right here.

Miller 91 Supercharger
Miller 91 Race Car
Miller 91 Race Car 12
Miller 91 Race Car 9
Miller 91 Race Car 8
Miller 91 Race Car 6
Miller 91 Race Car 5
Miller 91 Race Car 4
Miller 91 Race Car 3
Miller 91 Race Car 2
Miller 91 Race Car 1
Miller 91 Engine
Miller 91 Engine 1

Photographs courtesy of RM Sotheby’s

Miller 91 Race Car 5


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