Still more replies to McLaren F1 questions and com
Discussion
Tony,
On some cars that I have driven at B'thorpe, including the F1, stones can be propelled by one's own tyres and strike parts of one's bodywork that are usually out of range. Yes, stones are stones, but it must be because of their quantity and the fact that on the latter half of the straight you're going faster than you would do most other places.
By the way, I feel a bit guilty criticising B'thorpe's surface. The folks who own the place and their team are exceptionally friendly and accomodating, but I thought that I needed to be candid about my experiences there.
flemke said:Possibly, but in honesty, my car's got so many stone chips, that it's hard to gauge where and when I get new ones. In fact, stones tend to be the least of my worries at Brunters!! It's all those lines of parked cars they sometimes store at the end of the straight that tend to get me sweating.
Yes, stones are stones, but it must be because of their quantity and the fact that on the latter half of the straight you're going faster than you would do most other places.
Videos courtesy of Flemke are now online at www.pistonheads.tv
PetrolTed said:
Videos courtesy of Flemke are now online at <a href="http://www.pistonheads.tv">www.pistonheads.tv</a>
Ohhhh
Edited to add: Flemke, its brilliant to see one driven properly rather than left in a garage or collection.
Matt
>> Edited by matt_t16 on Wednesday 13th October 22:28
It definitely gets driven. Whether I am capable of doing that "properly" or not...I have ridden on circuits with the two men who for the last few years have done all the chassis sign-off and driver training for the factory. THEY drive properly.
You can see in the video how much lateral flexibility the (standard road) tyres have. Often I turn the wheel a certain amount, then add a touch more, and then a moment later trim it back a bit. Because of the tyres' lateral flexibility, there's a delay between when the front wheels change axis and when the contact patch follows. One gets accustomed to the delay, but the goal is to eliminate it.
Sounds like your setting yourself quite a challenge! On mine it was fairly easy to reduce lateral flex by increasing wheel size by 2" and running a 40 profile tyre, result is a large increase in feel and response but at the cost of ride quality and to a point handling ability on non-perfect surfaces. I suspect the same goals on a car such as yours won't be quite as easy to achieve.
Obviously you've looked into it at length, the standard fit tyres on the F1 were no doubt exceptional in the early 1990's but what are they like when compared with modern tyre technology? With the production of almost everyday cars which can generate lateral G levels comparable to the F1 (or in some cases above it) is there an almost off the shelf solution in the form of a change of tyre, or is there nothing available which would give the required results whilst maintaining the handling dynamic of the F1?
Matt
Obviously you've looked into it at length, the standard fit tyres on the F1 were no doubt exceptional in the early 1990's but what are they like when compared with modern tyre technology? With the production of almost everyday cars which can generate lateral G levels comparable to the F1 (or in some cases above it) is there an almost off the shelf solution in the form of a change of tyre, or is there nothing available which would give the required results whilst maintaining the handling dynamic of the F1?
Matt
Matt,
The road cars came with 235/45 and 315/45 on 17" wheels. The tyres are Michelin and are only meant for the F1 and only sold to the factory. They are speed rated to, I believe, 360kph or so.
The racing GTRs used 18" wheels, as ride quality was irrelevant. Subsequently, the road-going LMs and other standard F1s that were fitted with the LM's splitter and rear wing also had 18" wheels, with 275/35 and 345/35. These road tyres are also only available for the F1, and through the factory.
I expect to use either 18" or 19" wheels. The problem with simply using the LM road tyres is that, according to some people, the ratio of 275 to 345 is too big, so the understeer builds up too slowly for a road car. If however, we don't use the LM's tyres we are left with only a few options -there are not many tyres that come wide enough (335 or greater for rear) and also have a sufficiently high speed rating.
We will test different wheel widths and diameters. We may end up using the Bridgestones made for the Enzo.
A major disadvantage of bigger wheels is that you almost inevitably add weight in the worst possible way (unsprung rotating). This may lead us to go for a lighter-weight braking system (ceramic composite). I would like to avoid this but it may be the right thing to do.
Flemke,
Very very interesting, would going to ceramic rotors compensate sufficiently for the increase in unsprung weight? Obviously never having had the opportunity to have a sniff around an F1 up close I may be well off mark but I'd imagine the braking system (bar the rotors) is already incredibly light weight, even by modern standards, aren't the callipers and mountings machined from ally billet? Which only leaves the rotors (I take it their iron?) as a source of weight reduction.
On a side point its brilliant to see someone improving on what many see as perfection and even better to be able to discuss it with them.
Matt
Very very interesting, would going to ceramic rotors compensate sufficiently for the increase in unsprung weight? Obviously never having had the opportunity to have a sniff around an F1 up close I may be well off mark but I'd imagine the braking system (bar the rotors) is already incredibly light weight, even by modern standards, aren't the callipers and mountings machined from ally billet? Which only leaves the rotors (I take it their iron?) as a source of weight reduction.
On a side point its brilliant to see someone improving on what many see as perfection and even better to be able to discuss it with them.
Matt
matt_t16 said:
Flemke,
Very very interesting, would going to ceramic rotors compensate sufficiently for the increase in unsprung weight? Obviously never having had the opportunity to have a sniff around an F1 up close I may be well off mark but I'd imagine the braking system (bar the rotors) is already incredibly light weight, even by modern standards, aren't the callipers and mountings machined from ally billet? Which only leaves the rotors (I take it their iron?) as a source of weight reduction.
On a side point its brilliant to see someone improving on what many see as perfection and even better to be able to discuss it with them.
Matt
Matt, you'd be surprised at how much unsprung weight (and of course gyroscopic momentum) can be reduced with the switch to ceramic rotors. The original F1 disks are very heavy (cast iron). By contrast, the disks on the SLR are lighter than their calipers.
Frik said:
Flemke,
Very very interesting, would going to ceramic rotors compensate sufficiently for the increase in unsprung weight? Obviously never having had the opportunity to have a sniff around an F1 up close I may be well off mark but I'd imagine the braking system (bar the rotors) is already incredibly light weight, even by modern standards, aren't the callipers and mountings machined from ally billet? Which only leaves the rotors (I take it their iron?) as a source of weight reduction.
On a side point its brilliant to see someone improving on what many see as perfection and even better to be able to discuss it with them.
Matt
Matt, you'd be surprised at how much unsprung weight (and of course gyroscopic momentum) can be reduced with the switch to ceramic rotors. The original F1 disks are very heavy (cast iron). By contrast, the disks on the SLR are lighter than their calipers.
I have to admit I've not even looked at the new breed of Ceramic brake systems so any info forthcoming on these is greatfuly recieved
Do you know if ceramic based rotors are available aftermarket to mate to a standard bell PCD? I take it the 996/GT3 units are bell mounted? Matt
(I have tried to address these topics already, so apologies if I am <still> boring people.)
The original, standard car handles in a way that I did not like, including too-light straight-ahead steering, lack of understeer build-up below the limit, much understeer at the limit, rear lifts and shifts under hard high-speed braking, tendency to lift-off oversteer and general lateral instability at rear. It may be that in the hands of better drivers these things are not problems, but they bother me. I would add that, in public media, more than one world-class driver has been critical of the car's handling and has confirmed the same privately.
I have learned directly that what one reads in car magazines is unreliable, and the less that it is based on direct driving and living-with-the-car experience (as in this case), the more unreliable it is.
Most of the F1s get driven rarely if ever, so there just isn't a lot of evidence of how the car actually behaves.
The car was designed 10-12 years ago. The modelling and simulation power then available to chassis engineers wasn't a patch on what it is today. Likewise, perhaps even more so, a decade-old tyre design is inadequate by today's standards.
The car was designed to appeal to a wider range of tastes and needs than those of any one person.
I took my car to the man who is the best, ballsiest, smartest race driver that I know. He took the car out for an hour on his own, brought it back and said, "If you drive this car at speed in the wet, it will make you dead", (emphasising his point by drawing a forefinger across his throat). At this time I had already driven the car more than 20,000 miles, so I knew that this was tending towards hyperbole, but I also was relieved that I seemed not to have been crazy in my concerns.
There is a real limit to how much testing and development you can do if you're only going to build six dozen road cars, and matters are aggravated if you've never built a road car before. I am convinced that the reason that Ferrari's fall apart even today is that they don't build enough to do sufficient testing and development, and that's at a build-rate of 4,000/year.
Another factor that, in my completely ignorant opinion, profoundly influences the nature of the car is that it has wide front tyres but no power steering. There are benefits because of this, but there are problems as well: it required compromises.
What I can say is that at present the car's caster, camber, toe, springs, dampers and anti-roll-bar have been altered or adjusted, and the car feels much better to me. Driving the car now, the only source of instability is the lateral flexibility of the tyres.
Relative to the cost of the car, the cost of this project has not been that bad.
As regards unsprung weight savings, the starting point is that the standard wheels and tyres are quite light. As I recall, a standard 17" front wheel weighs something like 7.4kg. That is hard to match. I believe that the LM's 18" wheel/tyre combination adds over 20kg altogether to the standard weight.
I guess that the lightest-weight wheels for the job would be a version of the multi-spoke as used in Formula One. I don't think that they would look good on the F1, however, so I am aiming to replicate the originals in a larger diameter.
Yes, the F1 has monoblock aluminium calipers (four pot front and back), so there is little potential for weight-savings there. Pads are pads.
The big difference is in the rotors. The F1 has iron rotors like what you'll see on most everything else. The F1's might be a bit more efficient than "ordinary" rotors, but I doubt that there is much in it. Four ceramic-composite rotors weight about 15kg less than their iron counterparts. That amount is what I am guessing we will have added in order to get wheels and tyres that work better.
As the car's brakes will now fade after maybe four or five high speed stops, there is a bit of a performance gain in ceramics. You also benefit slightly from reduced wear, no corrosion, and no lag-time between pushing the pedal and when the pad begins to bite. Their biggest drawbacks are reduced feel and over-sensitivity.
It is perhaps worth remembering that G. Murray and his team made a big effort ten years ago to develop a carbon braking system for the F1, but mankind was not yet up to the task.
The original, standard car handles in a way that I did not like, including too-light straight-ahead steering, lack of understeer build-up below the limit, much understeer at the limit, rear lifts and shifts under hard high-speed braking, tendency to lift-off oversteer and general lateral instability at rear. It may be that in the hands of better drivers these things are not problems, but they bother me. I would add that, in public media, more than one world-class driver has been critical of the car's handling and has confirmed the same privately.
I have learned directly that what one reads in car magazines is unreliable, and the less that it is based on direct driving and living-with-the-car experience (as in this case), the more unreliable it is.
Most of the F1s get driven rarely if ever, so there just isn't a lot of evidence of how the car actually behaves.
The car was designed 10-12 years ago. The modelling and simulation power then available to chassis engineers wasn't a patch on what it is today. Likewise, perhaps even more so, a decade-old tyre design is inadequate by today's standards.
The car was designed to appeal to a wider range of tastes and needs than those of any one person.
I took my car to the man who is the best, ballsiest, smartest race driver that I know. He took the car out for an hour on his own, brought it back and said, "If you drive this car at speed in the wet, it will make you dead", (emphasising his point by drawing a forefinger across his throat). At this time I had already driven the car more than 20,000 miles, so I knew that this was tending towards hyperbole, but I also was relieved that I seemed not to have been crazy in my concerns.
There is a real limit to how much testing and development you can do if you're only going to build six dozen road cars, and matters are aggravated if you've never built a road car before. I am convinced that the reason that Ferrari's fall apart even today is that they don't build enough to do sufficient testing and development, and that's at a build-rate of 4,000/year.
Another factor that, in my completely ignorant opinion, profoundly influences the nature of the car is that it has wide front tyres but no power steering. There are benefits because of this, but there are problems as well: it required compromises.
What I can say is that at present the car's caster, camber, toe, springs, dampers and anti-roll-bar have been altered or adjusted, and the car feels much better to me. Driving the car now, the only source of instability is the lateral flexibility of the tyres.
Relative to the cost of the car, the cost of this project has not been that bad.
As regards unsprung weight savings, the starting point is that the standard wheels and tyres are quite light. As I recall, a standard 17" front wheel weighs something like 7.4kg. That is hard to match. I believe that the LM's 18" wheel/tyre combination adds over 20kg altogether to the standard weight.
I guess that the lightest-weight wheels for the job would be a version of the multi-spoke as used in Formula One. I don't think that they would look good on the F1, however, so I am aiming to replicate the originals in a larger diameter.
Yes, the F1 has monoblock aluminium calipers (four pot front and back), so there is little potential for weight-savings there. Pads are pads.
The big difference is in the rotors. The F1 has iron rotors like what you'll see on most everything else. The F1's might be a bit more efficient than "ordinary" rotors, but I doubt that there is much in it. Four ceramic-composite rotors weight about 15kg less than their iron counterparts. That amount is what I am guessing we will have added in order to get wheels and tyres that work better.
As the car's brakes will now fade after maybe four or five high speed stops, there is a bit of a performance gain in ceramics. You also benefit slightly from reduced wear, no corrosion, and no lag-time between pushing the pedal and when the pad begins to bite. Their biggest drawbacks are reduced feel and over-sensitivity.
It is perhaps worth remembering that G. Murray and his team made a big effort ten years ago to develop a carbon braking system for the F1, but mankind was not yet up to the task.
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