Exhaust Blown Diffusers: Pics from the past

In my previous articles on the subject, I’ve explained the Renault Re40 was the first F1 car to blow the diffuser(1983 first year of flat bottoms).  I got these pictures today and felt it was worth sharing them along with some insight from the man who brought the idea into F1, Jean Claude Migeot.

 This is what Jean Claude Migeot told me about the development

Exhaust blowing was on my menu of aero development during the first year of the flat bottom era (1983) as one possibility to recover some downforce. I was in Renault at the time in charge of aero and, after some checks on the engine bench as we were terrified to face another lag time (!) between throttle movement and downforce creation, I was given the green light to experiment in the tunnel. Exhaust blowing to create a fluid skirt on the side of the car (also tested early 1983) did not worked but blowing the rear diffuser was quite powerful (I remember something like 50 kg on the rear axle at full throttle whatever the speed). 

It was introduced at MonteCarlo in 1983 on the RE 40 and stay on it most of the season. It was kept on RE50 the year after (ask Derek Warwick!) and I introduced it also on the F1/86 (Canada 1986) when I worked for Ferrari later.

I remember well that in 1983 we were immediately protested by Brabham and Gordon Murray (on the basis of the exhaust blowing being a movable aero device) but Renault managed to win that case. A pity they did not return the favor to Brabham at the end of the season!!!

Diffuser blowing is specially good for traction out of slow corners but it has its downsides too. It increases balance sensitivity to throttle position which may create problems on high speed corners. Good and bad sides are quite depending on the driving style too: some drivers can take advantage of it more than others. The gas momentum available in the exhaust today is anyway much reduced compared to the turbo era (about 50%).

The Renault Re50 from 1984 split the 1.5l V6 twin turbo exhausts into two, plus the wastegate pipes, to create six outlets in the diffuser

 

From beneath you can see how the exhausts extend inside the diffuser Copyright: JC Migeot

The Benetton B196 blew the pair of exhausts from the Renault V10 into the centre of the diffuser

F1 Tech in ‘Race Engine Technology’ Magazine

This months ‘Race Engine Technology’ magazine has some interesting stuff for F1 Tech followers. There’s an interview with Mario Ilien, who explains the work he did with Mercedes-Ilmor including; Hydraulic KERS, a rotary valved V10 (+20k RPM & 78Kg) and of course Berylium for Pistons & Liners.
In the Report from the F1 British GP, the Editor interviews Adrian Newey, Also Costa, Sam Michael and James Allison. Covering several topics; the effect of engine powerdrivabilityconsumption, as well as gearbox design influence on aero, with Newey commenting the Pull Rod was a carry over from 09 & not a requisite for his RB6 design. While Ferrari confirmed their enginegearbox assembly is inclined at over 3-degrees, the first time I’ve seen a reliable quote confirming this fact. It was added that Sauber take this set up for their C29, while Toro Rosso have their own gearbox so have a horizontal drivetrain.
Lastly is a small section on how Sauber pioneered current gearbox design with a longitudinal gearbox, with the gears ahead of the final drive and contained within an aluminum case. It surprised me that Harvey Postlethwaite was involved in this, is there anything that man didn’t do in F1?

Not generally available in the shops and not cheap, but well worth a one-off purchase or subscription.

http://www.highpowermedia.com/mall/productpage.cfm/RET/2049/348121

RACE ENGINE TECHNOLOGY 048 AUGUST 2010

Intro: THE EDITOR
Racing powertrain technology is on the verge of a revolution; Ian Bamsey says this issue gives some hints as to what to look for

Upfront: MARIO ILLIEN ON FUTURE TECHNOLOGY
Ian Bamsey talks to Mario Illien about his pioneering work in Formula One during the V10 era and the future of race technology

Grid: IN THE NEWS
Peugeot’s con rod dramas; HPD’s new LM P2 V6 turbo; Le Mans’ Hybrid u-turn; John Medlen’s new role at DSR and much more

Dossier: PORSCHE 911 GT3 R HYBRID POWERTRAIN TECHNOLOGY
Ian Bamsey investigates how flywheel-based storage of recovered kinetic energy has been pioneered in professional racing

Race Report: BRITISH GRAND PRIX
Despite the ongoing engine freeze, Ian Bamsey discovers some significant powertrain developments at the British Grand Prix

Focus: CAMSHAFTS
Wayne Ward discusses the options available for the design, materials and manufacturing methods for race camshafts

Insight: RACE ENGINE INSTALLATION
Le Mans-winning designer Peter Elleray on the relationship between engine and chassis design, highlighting where their needs conflict

Focus: THE GEARBOX
John Coxon explains key points in designing and building a motorsports transmission – from the gear teeth to choice of differential

Race Report: LE MANS PROTOTYPES
Ian Bamsey gives a rundown of the various engine strategies deployed by this year’s Le Mans Prototype competitors

PS: SAUBER C12 TRANSMISSION
How in 1993 Sauber’s first Formula One car prompted a major shift in transmission technology

To view a sample article from this issue please click here

Price £12.50