An Afternoon at Aldon
Dyno Testing a Couple of Dallaras at Aldon
Automotive. This report is NOT about the result of the
tests but about the process behind it.
The issue of Toyota 3SGE-based Piedrafita engines in
Monoposto ("Mono F3") has been discussed for several
years. The problem is that Monoposto engines in the class
are defined by choke size and components, whereas the
Piedrafita, whilst having a measurable choke size, is
fundamentally a seal with an engine built round it. If you
break the seal, you've either got a very expensive anchor
for your boat, or you can take up hillclimbing and be
uncompetitive. Until now we've not had enough information
to do anything other than treat the Piedrafita as an F3
engine and impose the 25 mm restriction we use for all F3
engines. So if we want to decide what we can do to make it
comparable (whilst not, for cost reasons, becoming the
"must have") the only way is data.
Fortunately we have some people in Mono who are willing
to make an effort for the club for little or no
recompense. Nick Harrison and Ray Rowan volunteered,
respectively, an F302 and an F305 with a Mono 3SGE and a
Piedrafita 3SGE. Russ Giles got some sleeves machined up,
and the Treasurer was anaesthetised for long enough to
sign a cheque. And so on a cold February Monday we all met
up at Aldon Automotive in Brierley Hill.
Aldon was started around 40 years ago by the current
proprietor Alan Goodwin with a partner who has since
retired. Alan was an ex-Austin apprentice, so was skilled
in BMC A-series, a stalwart motorsport engine from the
50's to...well I can't say because it's still going. In
fact, there was an A40 and a Spridget (both A-series
powered) in the collection car park, together with a GT6.
Younger readers can google them. All of us at the test
recognised them. They've also developed a
business servicing and tuning modern high performance
road cars and competition vehicles, and even built their
own sports racer some years ago which Alan still
hillclimbs. And they have a parts shop too. But the reason
we were there was to use their rolling road.
I've been incompetent in single seaters for over 30
years, so it's perhaps surprising that I've never
encountered a rolling road in anger before. I'm not
counting tow car MOTs. Aldon use a MAHA (Maschinenbau
Haldenwang GmbH & Co. KG) dyno, in which the power is
absorbed by eddy current brakes. These are
electromagnets which work on metallic rotors. The
resultant heat is dissipated by air cooling. In case
anybody is thinking of rolling-road testing their car, I
will describe the process.
The test is run by Aldon's operator, not the car
owner/driver. In our case, it was the hugely experienced
Roger Bradley. After satisfying himself on the safety side
with the tie downs, he warmed the car up. This involved
running it against the rollers to run against constant
resistance and then at constant speed. Around this time
Roger calibrates the dyno so that, in the chosen gear, the
recorded revs on the dyno match the revs on the car.
It's important to warm up both the engine (for obvious
reasons) and the driveline because the latter needs to be
in a steady state. This is because when the test is run,
once maximum power is reached, the gears are disengaged
and the car coasts. The dyno measures the resistance
within the driveline by calculating the rate at which the
rollers are slowed.
I don't wish to trample on Russ's toes as he will be announcing the conclusion when it has all been ratified. However, a few points became clear from the tests:
Many thanks indeed to Nick Harrison and Ray Rowan for
providing the cars, Russ Giles for providing the sleeves
and for managing the tests, to Roger for his patience, and
to Alan Goodwin for providing a most useful facility at a
very reasonable price.
Disclaimer: The above represents only the unofficial view of the writer and not of the Monoposto Racing Club in any way whatsover. Subheadlines and captions are not originated from the named author. We are unable to reproduce results due to copyright reasons. If any pictures are copyright and the owner wishes them removed please email us.
The Aldon premises
A naked F302
Nick watches Ray fuel up the F305
Nappy fouled the mechanism at first trial
The Mono car showing the restraints
A restrictor in the airbox