McLaren M24

[Sea Fury]

How closely was the McLaren M24 Indy car based on the M23 Formula 1 car?

There is certainly a strong family resemblance.

[Automotive]

never saw that Teddy Yip version. Is that period accurate?

i have photos of the real car on a trailer at Milwaukee. Should scan and post for accuracy

[DaveL]

How closely was the McLaren M24 Indy car based on the M23 Formula 1 car?

There is certainly a strong family resemblance.

The M24 is an M23 with a turbo DFX instead of the NA DFV Cosworth, and of course the wheels are different sizes so the suspension is modified accordingly.

[AlfaRomeo182T]

The McLaren M24 was a direct descendant of the F1 M23... as was the M23 of the M16. Obviously, as DaveL remarks, mechanical components changed to adapt to USAC racing.

To present both, a cutaway find on the internet:

McLaren M23

Pinterest


McLaren M24


Pinterest


The idea of putting a DFV behind a McLaren M16 dated back to 1971-1972, when McLaren tested a ex-M19 Cosworth DFV and running gear at the back of the car. The test was a complete success, and prompted the McLaren M23 design for Formula 1. Then, after Parnelli early achievements, McLaren decided to adapt the M23 Cosworth DFV to USAC regulations + turbo.

Chassis conception was similar. Panels and materials were adapted to regulations (a little bit more heavy for USAC), tank fuel capacity and hose was different, with two entries at the left (Formula 1 has one entry, on top of the chassis, as the was no request for refuelling during the 70's), an some minor details of roll bar and dashboard.

From a mechanical point of view, the DFV block had similar was bolt-on points to the chassis. Of course, the engine had its stroke reduced to match the engine limit of 2.65 liters of USAC (from 64.8 to 57.3 mm) + a turbo at the back, on top of the gearbox, as was the pattern during the era. Gearbox was a 4 speeds Hewland, adapted to the high speed of USAC ovals, different of the 6 speed gearbox of the Formula 1. Radiators were a little bit bigger for the Turbo engine version, as to accept the demands of a more powerful engine (900 hp/9000 rpm VS 485 hp/10600 rpm)

Suspension pick-up points was practicaly identical, specially at the front of the car. Rear track was slighty different, with inboard brakes on the Formula 1 car, and outboard on the M24 version. Wheels and tires has its differences as well (15 in. USA vs 13 in. F1.

With a heavier chassis and engine, M24 was about 100 kg more than the M23 with 595/600 kg. Top speed was completely the opposite, with a M24 capable of 340/345 kph, versus the 300 kph of its european ascendent.

Both cars were one of the best cars of its era, and an example to other competitors of how to build a winning auto.


As to complete, some pictures (is very important to see changes, not only read it...)

McLaren M24 vs McLaren M23 Chassis
Note the simlar pattern of both, specially the front track and middle section of the chassis.

Pinterest / Wikipedia


Their rear track, with engines and suspesions.

Pinterest / Wikipedia / Reddit


And finally, link to their technical specifications:
McLaren M24 1977 - http://www.dlg.speedfreaks.org/archi...autos/3648.php
McLaren M23 1976 / 1977 - http://www.dlg.speedfreaks.org/archi...autos/3596.php / http://www.dlg.speedfreaks.org/archi...autos/3598.php

[Gurney36]

The M25 F5000 car was another pea in the same pod, design-wise.

[Qlander]

never saw that Teddy Yip version. Is that period accurate?

i have photos of the real car on a trailer at Milwaukee. Should scan and post for accuracy

Yes. Vern Schuppan finished third as an owner/driver in the 1981 Indianapolis 500 driving with this livery. Besides Yip and Trueman, I believe Jim Immke was also involved in the effort.

[Qlander]

The M25 F5000 car was another pea in the same pod, design-wise.

So close that the lone M25 ended up having a DFV installed and ran in Formula One races.

[Turn13]

Underrated thread bump

[Pelican Joe]

Underrated thread bump

Agreed. I've long been fascinated by this chassis.

[Jamski]

Was there a rule change in 1981 that removed skirts from the flat-bottom cars? I'd have thought that the M24 could've remained viable at least another season.

[Pelican Joe]

Was there a rule change in 1981 that removed skirts from the flat-bottom cars? I'd have thought that the M24 could've remained viable at least another season.

Good question. I've never read anything about a rule change, but it could have happened. I think one factor could have been the end of any real development of the chassis after McLaren left following the 1979 season. I think the used car market was fairly robust, too. Looking at the season opener at Phoenix there was a real mix of chassis: 2 year old PC-6's, year old PC-7's, Eagles, used Wildcats. Tony Bettenhausen had a solid season with a M24 in 1981, until he wrote the chassis off halfway through the year.

[editor]

Was there a rule change in 1981 that removed skirts from the flat-bottom cars? I'd have thought that the M24 could've remained viable at least another season.

No.

[Jamski]

No.

Are you sure? I just looked at the qualifying pictures and the flat bottom cars, to a one, had the skirts removed. Why would they take them off unless it was mandated? I seem to recall reading in Autoweek that the owners of the older cars were complaining that the rule change really hurt them...it was meant to slow the ground effect cars but hurt the older flat bottom cars more.