The forced induction issue.
People driving 'blown' engined cars can be divided into
two categories: Gentlemen drive Supercharged vehicles while Cads have turbos.
I know that W.O. Bentley was initially horrified at the idea of any form of forced induction regarding it as somehow unsporting, but Tim Birkin's Amherst-Villiers blown cars proved the only way to compete with the might of the Mercedes SSKs. Supercharged engines are always special- that lovely finned aluminium lump makes such a great noise, whether its the yowl of a Shorrock, the scream of a pre War Mercedes Kompressor or the whistle of the Centrifugal blower on a Merlin engine. The saying " There is no substitute for cubic inches" is wrong. There is and it's a supercharger. Blowing an engine gives better torque and throttle response for lower weight than enlarging the engine. Superchargers are a civilised way of making one's car go faster.
Turbos (Exhaust turbine-superchargers) are tremendously
well engineered (they have to be, spinning at six figure rpms) but a much
cruder method. On the face of it they seem elegantly simple: No belts,
pulleys or chain drives, using the exhaust gases' energy to operate and
capable of producing very high boosts. So why do I think they are crude,
The answer is in power delivery. Despite what manufacturers will claim, all turbos have a 'lag' to some extent, requiring the driver to keep the revs up to keep the engine on boost. They generate ferocious heat, requiring intercoolers, heat shields and special oil pumps. They spoil the exhaust note, making it gruff and fluffy ( although I will concede the bangs and cracks from the rally cars are great!) Lastly they have been bolted onto some truly duff creations (XR3s etc.) in a cheap attempt to make them go faster.
This is written with my tongue very firmly in my cheek
and with apologies to Dob, whose Quattro is undeniably splendid. I've built
my own Shorrock- blown Midget engine though so that's why I'm biased. Still
look at the list of great supercharged vehicles there have been:
Mercedes SSK, Supermarine Spitfire, The Campbell Bluebirds, K3 MG Magnettes,
Delage Grand Prix cars, Le Mans Bentleys, etc.etc.
The picture shows a beautiful Shorrock installation in a Frogeye Sprite seen recently at Brooklands. Done exactly the way they were originally (although If I had a criticism it would be that titchy air filter!)
See the page dedicated to my Midget for more pictures of my installation. If you doubt its effectiveness my car beat over 100 others in a timed ascent of the Brooklands Test Hill in summer 2008 (see feature) Torque and throttle response are superb, with no nasty side-effects at all.
If you have a supercharging project of your own, I have amassed a fair amount of literature on the subject. It's mainly based on the Shorrock/Allard kits produced in the 'sixties. Email me if you want more information or have bits to sell... PR.
1. Le Mans Diary 2000 Five Go Mad at La Sarthe
2. Gentlemen and Cads The Terrible Turbo versus the Sublime Supercharger.
3. Hidden Brooklands. Poking around in the undergrowth.
4. The Mysteries of the Lucas Wiring System Explained. Well, you've got to have a system....
5. The Petrol head's Pilgrimage. USA Road Trip summer 2001
6. Brazilian Car Stereo. Choose your weapons.- Bob Marley at 50 Paces.
7. Restoring a Constellation. Never mind cars, Mike rebuilds airliners. - (admittedly not single-handed.)
8. Allan Winn - Breathing Life into Brooklands. Eoin Young interviews a fellow Kiwi
9. Son Of Mindless. The legends are true! A 4WD monster lurking in the Fens
10. Brooklands Double Twelve 2008. Event of the year.- Or how to compete against your own car..
11. Farewell to the QE2. Last voyage of a great liner