- There's an amazing amount of technology
that has trickled down over the years from Formula 1 and we see this technology
being applied to our every day road cars. Unfortunately it's not that often that we
get the opportunity to get up close and personal with a genuine F1 car and find out
some of the secrets that made these cars so fast. Of course as the cars age and they fall away
from being current, we can get some insight. So we're here with Tim White from Garage 59
and beside me here is a 2000 model McLaren MP4/15 powered by a Mercedes
engine. This particular car was the car that David
Coulthard used to win Monaco in that particular season, and we're going to find
out a little bit about what makes this car tick. So Tim, for a start, let's go into the
engine. We've seen some massive variations in the
engine configuration with F1 over the seasons, this was powered by a Mercedes
engine, can you give us the specifications in terms of cylinder count and capacity? - Yeah certainly so this was a V10,
three litre engine, in it's day it would've been making something around about
900 horsepower. It would've been running about 18400,
something like that, top RPM used. - Now I just want to come back to 900
horsepower from a three litre natually aspirated engine, these sort of numbers,
we normally associated with forced induction and this is really one of the
tricks where it comes to naturally aspirated engines. What we really want to do in order to
make a lot of horsepower is we need to make torque at very very high RPM and of
course to make torque we need air flow, and this is where that RPM limit you just
mentioned, 18400. And we saw the RPM limit over the seasons
of F1 creep up and creep up. The problem with very high RPM ranges
is the valve spring technology. So can you tell us how this was dealt with
in this Mercedes engine? - Yeah certainly so on this particular engine
as has been common in Formula 1 for many years now, it's a pneumatic controlled
system. This engine in particular was quite special
in that it had a system which was variable to base on RPM mapping. - You're talking about the pressure there
was variable versus RPM? - Correct yes so it enabled us to run a low
pressure, at relatively low RPM. When I say relatively low I mean sort of
9000, 10000 RPM, something like that. - That's very low yeah. - Yeah indeed. And then we could, basically this meant that
we could run a much lighter weight valve gear so we didn't have to protect
against some of the forces that you'd see traditionally with a fairly heavy spring
that could go to the sort of levels that we would have to go to. And then as the RPM rose we would increase
the spring pressure effectively by increasing the pneumatic pressure. And then as the RPM came down we would
bleed that pressure off. What enabled us to do this was the
fact that we had an onboard compressor. So the architecture of the system was an
onboard compressor, a reservoir bottle, which is what the system drew on basically. And then a fill injector and a return or
dump injector. We call it a dump injector because it didn't
actually return it to the circuit, it dumped it to the, basically to the crank
case. - So by controlling those two solenoids or
valves, or injectors as you've just called them, you're controlling the compressed
air flow into the valve train in the cylinder head and then out to maintain that
pressure target? - Yeah that's exactly how it ran. We also used that circuit to regulate the
bottle pressure as well by putting an offset on the demand of those injectors. So if you were asking for some amount
of pressure, you'd look at the bottle pressure as well. If you had to bleed some of that down,
you'd open the injector more which would force you to over pressure and then
the dump injector would realise that it's over pressure and it would get rid of
that pressure. That would cause a high usage of the air
and that's what would bring the bottle pressure down. - Alright you've just brought in a huge
amount of information, I want to dive back in and unpack a little bit of that. And I think probably the best place to start
is why do we need to use pneumatic valve springs, what is wrong with a
conventional steel wound spring, where are the limits for that in an F1
engine? - Yeah so I think obviously, an F1 engine's
going to 18400, 19000 and even 20000 in later times. Obviously controlling the
spring mass, or the mass of the valve train with a spring, there's a lot of weight
involved. These have got no moving weight really
on the valve train, retainers are very small, very light, lightweight seals,
low drag, low friction. Obviously one of the problems with one
of these engines is when you're running at that kind of speed, the frictional levels
go through the roof. So anything you can do to reduce the
friction, the motoring forces, is a gain and an easy win really. - Now with an engine that runs to 18400
RPM producing 900 horsepower, it's reasonable to say that that's going to
be a relatively peaky rev range and of course with a seven speed, essentially
semi automatic transmission, the driver for the most part can use a
relatively narrow rev range. But the interesting part was you mentioned
off camera earlier that that's actually not always the case so can you talk to us
about the rev range that the car does use on some of the circuits. - Yeah certainly so this type of engine,
when you're running at a circuit, like Monaco is a good typical example of
a very dynamic circuit, in the hairpins there you would be running
down to about 3800 RPM in first gear, obviously not full throttle. But nevertheless it's got to drive down
there. And then through the tunnel and pulling
full throttle through the gears, you'll be running full RPM so 18400,
so 14000, 15000 RPM rev range. So you've got to, it's drivability is the
biggest issue. The other place was where it gets
difficult is somewhere like the old Hockenheim track where you have
very high speed. For the race we would use typically
first gear just for starting and not on track, it would be used, so we'd have
six usable gears on track. But they've got to stretch up to something
around 360, 365 kilometres an hour. And the slowest corner, yeah it's pretty
slow. So you finish up with a bigger rev drop
through the gears than you would ideally like and this can compromise you
on the kind of mid, not the very slowest corners but kind of the second, third gear,
typically third gear where you would be lower in RPM but second gear would make
the car unstable through the corner. - Now with a relatively peaky naturally
aspirated engine we tend to see, if we run the engine on a dyno we get
a relatively peaky torque curve, and that can be problematic if you need
to use 14000, 15000 of that rev range. So can you talk to us about some of the
tricks that were employed in this era to try and fill in that torque curve and get
rid of some of those troughs. - Yeah certainly so typically this engine
would have a couple of troughs below peak torque. And the second one probably difficult,
you would find you would, it would encounter more than the lowest one. So this would happen at around about 13000
RPM, there was quite a big trough there. To help fill that in, we would have an
active trumpet. This has got a really good effect of
filling that hole in. - So you're talking there about variable
length inlet trumpets, so sort of a tuning effect for that inlet trumpet versus the
RPM? - Yeah indeed so it was exactly that,
versus RPM trumpet map which we actually used to just use in one direction. Although, when you're sitting on the dyno,
you could get ultimately bigger numbers out of it by having a trumpet map that
went short, long, short, long, short again for high speed. Drivers didn't like this. Although you couldn't actually see the
torque difference on the dyno, it looked like a smooth torque delivery. When you gave that to the driver, they felt
something that we can't see on the dyno. Whether it's a noise or genuinely it does
do it is difficult to say. So what we would tend to do is compromise
it slightly and just go from long to short. - Now even with doing that, you're talking
about an engine that can change between 3800 RPM and 18400 RPM, I'm guessing
just about a split second. How are you achieving such fast and
accurate control of those trumpet lengths? - We have a 200 bar hydraulic circuit. This feeds a lot of the systems on the car
but if we just take the trumpets, trumpets and throttle 'cause they're very
similar. This was controlled with a moog valve. It's a high speed kind of electromechanical
valve that can deal with a very small current and they are extremely fast acting. So with 200 bar behind it, it moves
pretty fast. - You've just mentioned that system,
that hydraulic system is used for multiple aspects of the car, you've got obviously
the trumpet length we've just talked about. You also touched on there the throttle. So essentially these days we see drive
by wire throttle electronic control, generally quite common in road cars as
well as professional motorsport. You're using hydraulics, can you just mention
the differences there where the hydraulics are superior to electric drive
by wire? - So there's a couple of things really. Probably the prime thing on the car,
like a formula one car here is everything comes down to weight. A lot of the things are on there because
of weight. So we have to have a hydraulic supply
on the car. And given that we have to have the
hydraulic supply on the car, we use it for everything. I think in the day when this was active
then the electronic or electric motors controlling things like throttles and such
were not really at the level where they are today. Today I think it's fair that you could take
a slightly different approach to it. In fact I know some other cars which
do take a different approach. But given that you don't want to carry
anything along that you don't have to carry along, nothing gets taken for a ride
on a Formula 1 car. - Alright just carrying on that theme with
the hydraulics there, we haven't really talked about the transmission other than
to say it's a seven speed semi automatic. So essentially paddle shift, not really too
unusual compared to what we see in a lot of road cars and GT3 race cars for example. Can you tell us how that shift works with
the hydraulic system? - Yeah it really is nothing too special. There's a switch that commands the shift,
everything has to be commanded by the driver in this period. - So this was a legal requirement of that
period? - Yeah correct, correct. - So this was very much a time when there
was no driver aids. So everything had to be an input from
the driver. So on this car we have a paddle shift which
essentially is a switch, nothing special. And it's this switch that gives the command
to the ECU which then activates the shift sequence. - So essentially we're just talking about a
conventional dog engagement seven speed gear box, albeit this one is hydraulically
actuated? - Yeah absolutely, nothing special at all
really. This era wouldn't have been running a
seamless shift. It would be what you would consider a
conventional sequential gearbox. So everything had to be requested by the
driver, so no automatic shifting and everything had to be a single input. So you could only do one gear at a time,
you couldn't stack them in this era. That did change subsequently but in this
era, it was a one switch position move equals one shift. - Bit of a simpler time. - Yeah bit of a simpler time. - Now again we're just talking about the
transmission, we've mentioned the hydraulics there and this is another area
that hydraulics is used is the clutch control. So conventionally we do use hydraulics
for the clutch but a much lower pressure. And normally it's actuated with a pedal
that the driver uses his foot to control. In this instance it's controlled via paddles
behind the steering wheel. So can you tell us why the steering wheel
paddles are used instead of a foot pedal? - So the steering wheel, so the clutch on a
Formula 1 car is really only used for pulling away. Once you're moving, the clutch isn't used
anymore. So with two paddles and on the hands,
it enables you to do a very nice launch by using the two paddles. I think this has become common practice
for many Formulas now where you have the option to run an electric or hydraulic
position control, or some kind of position control of the clutch. So typically what the driver would do was
he would move one of the paddles to the bite point and he knows it would be around
about 50% of the travel. There'd probably be a mapped flat area in
there so if he misses it, he can miss it by a little bit and still be in the right
window. The other paddle he would pull to full
travel, so that's with the clutch disengaged, enabling to select first gear. As soon as the lights would go out,
he would drop the, we'll call it the higher paddle, but the one that is pulled all
the way, which meant that then the control system would be looking for the
highest clutch input which would be the one which would be sitting on the bite
point. So what this means is he's very quickly
at the bite point and driving the car straight away, he's not trying to find it
somewhere around 50%, or 70% of the travel or something like that. - Alright look Tim it's been amazing to get
so much insight into what makes this car go, just that insight that really for
most of us mere mortals no one really gets to find out those sort of details. And I think probably a key factor that I
overlooked is that in a prior lifetime, you actually worked as the engine
engineer for David Coulthard over a period of about 10 years around this
era. So for those watching, this is why Tim
knows so much about this particular car. But thanks for the chat Tim and enjoy
the rest of your weekend. - Thanks very much, thanks for the chat. - If you liked that video,
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The sound alone made F1 worth watching back then
Great video.
It brought back many good memories of attending the first 4-5 USGP's at IMS.
At one point I was thinking: "wait, did he just say...?" A moment later Andre "can we just go back a bit, you mentioned hydraulics operate the throttle..."