The thing about this so-called "race" is the design engineer is factored
out of the equation. Individual cars have the HP and car weight adjusted
to make the performance equal. Unlike Formula 1 where good engineering
design counts.
Not really a car race at all. They should just let all the drivers run
around the track using just their legs for 24 hours and see who wins :)
Mazda has entered their silly carcinogenic diesel in this race and
within an hour one is having problems.
Another silly car entered is the so called delta wing with a billet
block Mazda Miata engine. The "engineer" that designed this car does
not understand weight transfer in a corner. In the first hour it spun
out once.
Paul Lamar
I thought the Delta Wing had an affiliation with Nissan. Trikes do not
have exceptional stability.
Dale Davies
Last year.
Nissan/Renault wised up :) This year it is a Mazda Miata based engine
but the block is NC machined from a billet.
Paul Lamar
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As of right now the Delta is 16 laps down and last in class.
There is a difference between handling and cornering speed.
Paul Lamar
------------------------------------------
They interviewed John Doonan on TV and he mentioned torque and steel
pistons. Steel pistons in a diesel is a drastic way to deal with piston
over heating. That tends to limit RPM and HP because of increased piston
weight and inertia forces on the connecting rods.
I wonder if they tried oil squirter's on the bottom of the heads of the
aluminum pistons? Standard in most aircraft piston engines and probably
truck diesel piston engines.
They could also go with beryllium aluminum pistons, BeAl is .7 times the
density of aluminum pistons and good to 750 F while aluminum pistons
start failing at 500 F. Outlawed in F1 but the Rolex organizers might
not know that.
Cars accelerate and airplanes fly on HP with a good gear box and not torque.
They could always try talking the Rolex organizers into allowing them to
double the displacement of the diesel engine.
Mazda won the last Rolex race in 2012 with a RX8 rotary engine.
Now they are 12 laps down and running near the back.
How the mighty have fallen.
Paul Lamar
Paul,
Diesel engines are limited in their rpm by the delay time between the
injection of fuel and the start of combustion. That's why car diesels
have peak power around 4000 rpm and redlines around 5000. Even Mazda's
racing diesel only revs slightly higher. Therefore any additional weight
imposed by steel pistons has no effect on the engine's revving capability.
Csaba Csere
Do all diesel passenger cars use steel pistons? I don't pay too much
attention to them.
Are new diesel cars required to use urea anti pollution fluid in
California like the trucks?
("The BlueTec system injects water-based urea solution into the exhaust
system. The ammonia produced by the hydrolysis of the urea reacts with
the nitrogen oxide emissions and is converted into nitrogen and water
within the catalytic converter.")
The BSFC of the rotary gets much better when they are leaned to 18:1 but
the NO goes
way up.
I just found out that the Mazda diesel's are using cast iron blocks.
For some reason I got
the idea that they were aluminum. Mazda are not very fourth coming with
the tech.
Last Daytona race info I have is they were 54th in a field of 67 OA.
Even the delta is ahead
of them :)
Now that Form 1 is using turbo compound I hope Mazda wakes up and uses it
with the rotary. IMHO a potential 30% reduction in fuel burn without
the pollution problems of the diesel and also without the exhaust valve
problems
of the piston turbo compound.
Paul Lamar
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