193 replies to this topic

[Mobil1NSXR]

We've heard it a few times before. The American fan, the odd racer.

They tell you that torque is the most important aspect of a racing car. They ridicule cars with lower displacement because the torque is "weak". These cars feature high HP output but relatively weak low end torque.

I've always assumed that handling is the most important aspect of a car.

If you can enter a corner 20 km/h faster than the opposition, thats 20 km you don't need to waste time accelerating back up to.

I think HP also matter more than low end torque. HP just means toruqe can be sustained at higher RPM's, which is important for top speeds.

Am I crazy, or do a lot of "torque fans' not get the point?

Sure torque is important, but it won't get you back that lost 20...will it?

It's cornering speed, and that's why the William's hasn't been able to use that advantage over the previous 3 years. Now they don't even have that advantage anymore.

[Lukin]

Im not a specialist on the topic so some of this may need to be confirmed.

There is a good passage at the start of the Milliken book, along the lines of "winning in motor racing comes down to maximising your acceleration in the right direction."

Its true, and subsequently there are thousands of factors that make a racing car a winning one. You cant really compare the contribution these two aspects (torque and handling) make to the performance of the car. You can have brilliant handling but without any go it's useless other than providing a nice moving chicane for other cars on the track. Similarly having a tonne of torque might be useless if the car would rather roll over than turn, imagine a top fuel dragster at Monaco?

When looking specifically at torque, its dependant on the sort of racing. Formula 1 cars dont need huge amounts of torque but a V8 Supercar does. The torque the engine provides is transmitted to the wheels to accelerate the car and overcome the resistance it's inertia provides. The more inertia (which is directly related to weight) the more torque required.

Same applies with road cars. Since power is the rate of torque delivery, 200kW can be generated by an engine with 347Nm @ 5500rpm or another engine with 239Nm @ 8000rpm. Which engine would you rather have in a 1600kg car? And what would you rather have in a 800 kg sports car? I know this example is crude, it depends on torque delivery and the other factors, but the point is the same.

Different horses for different courses.

Sorry if some of this is a little off, correct me if I am wrong.

[schuy]

Originally posted by Lukin
When looking specifically at torque, its dependant on the sort of racing. Formula 1 cars dont need huge amounts of torque but a V8 Supercar does. The torque the engine provides is transmitted to the wheels to accelerate the car and overcome the resistance it's inertia provides. The more inertia (which is directly related to weight) the more torque required.

I'm no expert, but what you said is precisely it.
I'm not too knowledgable on the torque figures of F1 cars(can anyone ellaborate?) but weighing only 600kg the inertia is extremely low making the need for ample torque almost irrelevant.

On the other hand:
Mobile, you ellaborated on the issue of getting into a corner 20kp/h faster and(I assume) coming out of it 20 kp/h faster as well.
Thing is, with higher torque figures, the opposition can quash that speed margin relatively easy and perhaps even sustain a higher speed prior to reching the next corner.

Your thoughts?

[Ben]

When I was on the Motec Claude Rouelle seminar a race engineer from Cosworth Racing was there (he's Webber's engine guy this year). He alluded to there being torque as well as traction and power-limited acceleration. I had never considered torque-limited acceleration before and I'm still not totally sure what this means. Whether it's to do with the inertia of the driveline or not?

Anyway, not really answering the question, but something else that might like discussing.

Ben

[perfectelise]

Aerodynaamic downforce effectively increases the weight of the car without increasing the inertia.

But is there in fact an increase in resistance to acceleration?

Consider the way air resistance rapidly increases with speed. This resists acceleration like a high inertia, so F1 cars do need good torque.. No?

[Wuzak]

Surely gearing is an important factor here?

If an F1 engine has 900hp at 19,000rpm and a NASCAR has 800hp at 9000rpm, but they are geared so they are both doing 200mph and they have the same effective tyre diameter then the F1 car has a greater amount of thrust at the wheels. Which is, I would think, the important thing.

With an F1 engine the aim is to gear the car so that the engine remains in its effective power band as much as possible.

[RDV]

We shall have to use an analogy, as long as it is remembered all analogies are false, because they do not describe the "ding an sich" , but something similar.

We have energy and we have power.

Energy can be described in Joules (J), kiloWatt*h, kilopond*m, PS*h, kcal, ft*lbf or Btu (British thermal unit).

Power can be described in Watts (W), kiloWatts (kW), kilopond*m/s, PS(metric horsepower, comes from Pferdestarke also known as ch, cheval vapeur in French, and is equivalent to 0.7355 kW, but we are getting a bit ahead of ourselves), kcal/s, hp or Btu/s.

Horsepower is dependent on torque, the full description of horsepower being the torque applied over a period of time.. the definition of one horsepower is (in SI) equal to 745.7 Watts (W)

..the difference in PS (SI or metric) to hp (Imperial) is sufficient to cause a certain amount of confusion, not to mention different ways of measuring , such as DIN or bhp.Suffice to say 1 hp=1.0139 PS, so a power output in SI (PS) will seem roughly 1.4% more than the same in Imperial units...

..it can be also written as (using the unit of force in SI the kilopond - kp)

the kilopond is defined as the force with which a mass of 1 kg exerts pressure on the surface beneath it at a place on earth. Since G=m*g

1kp =1kg*9.81 m/s^2= 9.81 N (Newtons)

for torque (which can be described as energy)
1 kp*m=9.807 J

and for power=

1kp*/m=9.807 W

..therefore power is defined by torque over time....

this is conveniently described for engines as

P=M(torque)* angular velocity(rad/s) or alternatively= 2*PI*Torque*min^(-1)

therefore power , as we can see , is directly related to the RPM.. still with me?

.. engines which are turning over at low RPM... for example a big stock-block V8 will be producing a lot of torque, but at low RPM (there is more to it, as the highest torque is produced at low rpm and tails off as rpm increases)...

To introduce the analogy here (remember all analogies are false) its like trying to push a car, the highest effort is just as it begins to move, as it picks up speed you cannot keep the same rate of acceleration as it is moving faster.... similarly for the flame front expanding the gas pushing the piston... which is what is producing the force on the piston head, that multiplied by the crank throw lever is giving you the torque. In a IC engine the torque will go down with rpm....after a certain point , as engines normally have low torque at the beginning as flow rates not optimised for part throttle and low air ducting speeds, valve timing , etc...

What we will see at the output end of the Internal combustion engine is the net horsepower, defined as usable horsepower , where the auxiliary equipment necessary for the operation (water pump, ignition equipment, fuel-injection pump, oil pump, scavenging air, etc) are driven by the internal combustion engine (as defined by DIN1940).

.. so any discussion of torque or horsepower is really a circular one... F1 engines will have nominaly low torque , but when applied at over 18000 rpm produce quite healthy power figures...

What I presume we are discussing here is a fat torque curve (IE maintains it value over a wide rev range before decaying) against a "peaky" torque curve, where it happens all at a narrow rpm band eg. as in 125cc two-strokes who end up requiring a 16 speed box to be able to use the power.

Because the force applied to the piston crown by the gas (defined by BMEP brake mean effective pressure) is what will eventually be transformed into torque , bigger engines with preferably bigger piston areas will tend to produce more torque, if we want to go the other route, for the same cubic capacity , but smaller dia pistons , we must increase the stroke, thus increasing the lever arm..)

As F1 engines are displacement limited by the rules, the fastest way to increase power is to increase the rpm.... not exactly as simple as that, we have to factor in increased friction , more heat dissipation to cope with , bigger pumping losses etc... but you get the picture.....

[WPT]

Power is the time rate of doing work. It takes work to accelerate a vehicle, so power delivered to the drive wheels is very important. A nice torque curve is user friendly and eases the task of the driver. WPT

[Bill Sherwood]

FWIW the way I explain torque/hp to people is to tell them about the difference between a late 1960's F1 engine and a current one.
They make close to the same torque I suspect, ie, around 290 ft-lbs odd, but instead of only running to about 11,000rpm like the 1960's engine the current ones run to 19,000rpm.
They both still have similar top speeds, ie, around the 320 - 340km/h mark, so the difference is in the gearing.
This means that the torque at the wheels (not the engine, it's not really relevent if you can rev the engine enough) is 19/11 = ~73% more.
That's a bit of a generalisation I know, but it gives you a bit of an idea.

[McGuire]

Engine A develops 140 hp at 5000 rpm.

Engine B develops 140 hp at 10,000 rpm.

Engine A displaces 2.0 liters and was designed to power a 2200 lb road sedan. Engine B displaces 1.0 liter and powers a 500 lb sport bike.

Theoretically, we could install the sportbike engine in the small sedan and, with appropriate final drive gearing, it would still achieve the same top speed. After all, both engines produce exactly 140 hp. However:

HP = torque x rpm/5252

so conversely,

Torque = HP x 5252 / rpm

That means we absolutely know that engine A develops 147 lb ft of torque at max hp rpm, while engine B produces only 73.5 lb ft. Essentially, we have half the engine torque available up and down the range with the sport bike engine. (Which is not surprising since it has half the displacement.)

This means that if we are going to use the sport bike engine in the 2200 lb. road sedan and expect to have anything like the original acceleration, we not only have to double all the gear ratios in the gear box and final drive; essentially, we also have to double the number of change speed gears in the box, because now the rpm drop between gears is twice as large.

So all else being equal, on a road course the 2200 lb sedan equipped with the 140 hp 2.0 liter engine will murder the sedan equipped with the 140 hp sportbike engine. The more slow corners there are on the course, the worse it will be.

And there is the value of torque in road racing. Yes: a smaller engine of higher specific output means a lighter and smaller engine package, which has many advantages in terms of handling, aerodynamics, etc. However, the tradeoff is less torque, which means a heavier, more complex gearbox which robs more friction and may introduce packaging problems of its own. AND it means more gearchanges per lap, when every shift costs hundreds of milliseconds where the engine is not supplying power to the ground, makes the driver's task more difficult and introduces more opportunities for error and breakage.

So that's why they say that on road courses and short ovals, Torque is King and there is no replacement for displacement.

So why all this emphasis on small, high rpm engines of high specific output for racing? Simple. Virtually all racing series impose displacement limits. If the displacement limits were removed in F1 for example, we would probably see displacements doubled starting tomorrow, with great hulking torque monsters bolted up behind the drivers. It happened before, under the 750 kg formula. With modern lightweight construction techniques, we could easily see displacements of seven liters or more in essentially the current chassis package.

[Scoots]

http://www.sportcomp...bble/index.html

[perfectelise]

McGuire

[Ross Stonefeld]

Originally posted by Mobil1NSXR
We've heard it a few times before. The American fan, the odd racer.

They tell you that torque is the most important aspect of a racing car. They ridicule cars with lower displacement because the torque is "weak". These cars feature high HP output but relatively weak low end torque.

eh? Where is this going on? Granted the average fan and teenybopper racing magazine is obsessed with trap speed (which mean sweet fa to lap time) but I dont know that anyone serious takes it seriously. Even torque is a bit overrated, it only helps you in one area of the lap. Give me tires that stick better, ill be faster everywhere.

[ciaoduc]

Check out this link...
http://vettenet.org/torquehp.html

[Mobil1NSXR]

Originally posted by schuy


I'm no expert, but what you said is precisely it.
I'm not too knowledgable on the torque figures of F1 cars(can anyone ellaborate?) but weighing only 600kg the inertia is extremely low making the need for ample torque almost irrelevant.

On the other hand:
Mobile, you ellaborated on the issue of getting into a corner 20kp/h faster and(I assume) coming out of it 20 kp/h faster as well.
Thing is, with higher torque figures, the opposition can quash that speed margin relatively easy and perhaps even sustain a higher speed prior to reching the next corner.

Your thoughts?

You guys make really good points! But the above seems to make it seem like the handler lacks power against the torque monster.

Let's take for example the 2001 JGTC series, the NSX-GT as anybody knew it back then was the handler, had relatively weak torque against the turbo rivals SUPRA, SKYLINE, but had a little more HP. It lacked a little less than 200 lb/ft.

It won that year because it handled, braked later and came out of corners faster. It accelerated plenty well too thanks to HP, not torque. Where it suffered was going uphill.

So let's just assume the cars are almost equal in HP, but have a chasm in terms of torque. The handler should win then? I'm not too technical so I'll just use the example above. Let's also keep in mind the NSX-GT is penalized 50KG (110 pounds) because of its mid-engine layout. The Torque monsters were 50KG lighter, but the NSX still handled beter.

So McGuire, your comments on cars of almost equal weight, but completely different handling/ power characteristics?

Keep it in 2001 pls, the NSX-GT is about 2 seconds slower than the opposition this year despite its new turbo package. That torque isn't doing it much good. Sad.

If anything, I think the NA engine promotes total harmony between chassis and engine.

Thanks!

[McGuire]

Originally posted by Mobil1NSXR


Let's take for example the 2001 JGTC series, the NSX-GT as anybody knew it back then was the handler, had relatively weak torque against the turbo rivals SUPRA, SKYLINE, but had a little more HP. It lacked a little less than 200 lb/ft.

It won that year because it handled, braked later and came out of corners faster. It accelerated plenty well too thanks to HP, not torque. Where it suffered was going uphill.

So let's just assume the cars are almost equal in HP, but have a chasm in terms of torque. The handler should win then? I'm not too technical so I'll just use the example above. Let's also keep in mind the NSX-GT is penalized 50KG (110 pounds) because of its mid-engine layout. The Torque monsters were 50KG lighter, but the NSX still handled beter.

So McGuire, your comments on cars of almost equal weight, but completely different handling/ power characteristics?

Thanks!

I wouldn't begin to know how to answer this...power/torque and handling are such relative qualities. In racing there are always horses for courses. And if the grip is there, a good driver can make things work when perhaps the package is lacking in balance.

There have been great race cars that consisted of essentially the big motor on a crude platform with no particular vices...and great race cars without much grunt but with very refined handling and braking qualities.

So who can say? I guess that's why it's so intriquing to watch it being fought out on the track. Some of my favorite races each year are at the SCCA Runoffs at Mid-Ohio, in the T1 and T2 categories. These usually shape up as battles bertween V8 Detroit iron of various kinds versus smaller, more expensive and sophisticated sports cars and GTs.

One year T1 featured Freddy Baker in a Porsche against a herd of Corvette Z06's. But as luck would have it, it rained...the great equalizer. Freddy did not have the power to muscle to the front, but he snookered them on a restart and that was all she wrote. From there the Corvettes may have been faster but they could never get a run on him. One Corvette driver was fit to be tied, even filed a protest which was disallowed.

Another year in T2 a Porsche Boxster S qualified on pole, chased by a flock of Camaros and Firebirds. That race was wet as well, and the V8s were also seriously hobbled by the lack of a decent rain tire in their size. One racer had discovered quite by accident that a Hoosier dirt track tire (which happened to carry a DOT stamp for homologation purposes and was therefore legal) made an excellent rain tire...the Porsche Boxster got tangled up spun off early and the V8s carried the day.

Power versus torque... torque versus handling...these are the kind of debates which will allow message boards like these to bargle on into perpetuity. Carry on!

[McGuire]

Originally posted by Mobil1NSXR
If anything, I think the NA engine promotes total harmony between chassis and engine.

Thanks!

All else being equal, I think NA beats turbo every time. In engines of similar output, the normally-aspirated example will invariably have a wider and more manageable torque curve.

[Scoots]

Originally posted by McGuire


All else being equal, I think NA beats turbo every time. In engines of similar output, the normally-aspirated example will invariably have a wider and more manageable torque curve.

For road cars, admittedly a totally different environment to the track, a small turbo engine does have the advantage of fuel economy when driven gently and awesome kick when hammered.

[WPT]

McGuire, engine 'B' would have twice the gear reduction as engine 'A' at the same speed, so torque at the drive wheels would be equal. Let's try this: suppose we have two identical cars with infinitely varible computer controlled transmissions. A roll-on acceleration test is to be perfomed. One car has the computer hold the engine RPM at the torque peak, while the other car has the computer hold the engine RPM at the HP peak. Which car wins the acceleration test, and which car has the higher top speed? WPT

[saudoso]

McGuire,

Displacement is in fact the easiest way to increase power. Forced intake is second easiest. Raising RPM is the hard way.

I agree that removing limitations would increase displacement right away. You don't see anyone running a 2.5L F1 car, with todays regulation. But then we would come to a point where size and weight are compromising performance and then enginers would start to build lighter, high rev engines. And that would require different material and better fabrication. And would be damn expensive like it is today.

You mentioned displacement regulations, but IRL, as an example, limits minimun engine wieght and max RPM. This is intended to keep costs down. If an engineer was alowed to, he sure would increase his RPM range.

[McGuire]

Originally posted by WPT
McGuire, engine 'B' would have twice the gear reduction as engine 'A' at the same speed, so torque at the drive wheels would be equal. Let's try this: suppose we have two identical cars with infinitely varible computer controlled transmissions. A roll-on acceleration test is to be perfomed. One car has the computer hold the engine RPM at the torque peak, while the other car has the computer hold the engine RPM at the HP peak. Which car wins the acceleration test, and which car has the higher top speed? WPT

Yes, but the problem with doubling the gear reduction with engine B is the drops between gears will then be twice as wide... or, why small, high speed engines require more gears in the transmission than large, high torque engines. We see that F1 engines now have 7-speed gearboxes. There are displacement limits in F1, but no rpm limits, and no limit on speeds in the gearbox.

If I understand your premise as you intended, the engine kept at max hp wins in both acceleration and top speed. (And you always gear a race car not for peak torque rpm but for peak hp rpm...and in the lower gears, often just above it.) Of course the transmission you propose does not exist, and will not appear anytime soon. Conventional transmissions don't operate anything like that either, so torque will remain a key factor in vehicle performance for the foreseeable future.

However, your example does raise several interesting issues...for example, if maximum efficiency is the goal, the engine would be kept at its torque peak. There volumetric efficiency, BMEP and BSFC are at their optimum. An engine's efficiencies fall off rather dramatically beyond the rpm of peak torque.

[McGuire]

Originally posted by saudoso
McGuire,

Displacement is in fact the easiest way to increase power. Forced intake is second easiest. Raising RPM is the hard way.

I agree that removing limitations would increase displacement right away. You don't see anyone running a 2.5L F1 car, with todays regulation. But then we would come to a point where size and weight are compromising performance and then enginers would start to build lighter, high rev engines. And that would require different material and better fabrication. And would be damn expensive like it is today.

You mentioned displacement regulations, but IRL, as an example, limits minimun engine wieght and max RPM. This is intended to keep costs down. If an engineer was alowed to, he sure would increase his RPM range.

Quite right. Without regulatory limits on displacement, the physical boundaries still exist and would be found. Just as with rpm now. It is kind of interesting to try to estimate where the physical boundaries would be for a conventional F1 car. Seven liters? Eight? I don't know. And it sure wouldn't be cheaper than the present rules framework, that's for sure. But it might open up some interesting areas for innovation, with a nonconventional, clean sheet car. How about a lightly-stressed, low-speed, enormous-displacement engine with its carbon-composite cylinder block integral to the monocoque with the driver sitting in the middle of it? Just thinking out loud...

It would also be interesting to see what F1-level development would do with the IRL rules regime (not that I am suggesting it). Over there the gains are very hard to come by, essentially boiling down to basic operating efficiencies. One could see how it could even possibly lead to some core advances.

[Scoots]

Originally posted by McGuire
There are displacement limits in F1, but no rpm limits, and no limit on speeds in the gearbox.

I thought 7 was the max number of speeds on an F1 box?

[McGuire]

Originally posted by Scoots


I thought 7 was the max number of speeds on an F1 box?

If so thanks for the correction, and now we know why they don't have eight.

[desmo]

Originally posted by McGuire


If so thanks for the correction, and now we know why they don't have eight.

I wouldn't assume that if the ratio limit was scrapped all the teams would go to eight. If I recall correctly at least as of a couple years ago the field was fairly evenly split between teams opting for 6 and 7 speed gearboxes. Obviously many reckon six is a good compromise.

I find interesting the theoretical question of, all else being more or less equal, what size NA engine would work best in something like a current F1 chassis if there were no displacement limit on a typical current F1 track. 5 liters perhaps? More?

[Greg Locock]

Whenever I get involved in 'blue sky' vehicle proposals (not as often as I'd like) I always suggest that a larger, less highly stressed engine might be a better overall compromise than a smaller high tech unit. This always gets shot down because the reality is that new engines are not really feasible for blue sky projects.

So, assuming that we now have the physics sorted out and understand that power, rather than torque, is the important thing, the question is, what 100 kg engine (or less) can you design that will give 900 hp? Without screwing the aerodynamics, reasonably efficiently, and with a low CG?

Approach 1 - marginal increase in volume

The first thing I'd look at is the weight breakdown of an installed engine, ie with all the ancillary gubbins installed. Then throw out all the high tech stuff, see how much that saves me and devote that to increasing the capacity of the engine. Then work out the power developed by that. If we can get the cg down a bit then we could trade off some ballast for engine weight as well.

Approach 2 - reduction in volume, increase in redline

However, the problem is likely to be that high speed is the most weight efficient (if costly) way of getting power, so perhaps we should look at smaller, faster engines. How about a pair of siamesed flat 6s or V8s, with central power take off?

Approach 3 - drastic reduction in redline

Supposing we go from the other end. Let's take a V10, throw out all the high speed rubbish, and limit them to 9500 rpm. How much weight can we pull out of the engine to compensate for the lower red line ? not much - a bit of crankshaft weight, and the conrods could be a lot thinner. But now we can increase the stroke, for virtually no increase in mass, in the reciprocating components at least. If we double the stroke we double the capacity, but even with the higher stroke the inertial forces are 1/2 that of the current engine. Block weight goes up a bit, and the crank gets heavier again. Hmm 900 hp from 6 litres is still pushing it a bit.

I'll go and have a play with a simple model of this to see where the 'optimum' might be.

[Dmitriy_Guller]

When people talk of engine torque, they're missing half the picture. Engine torque is meaningless without factoring final drive torque multiplier (from gearbox, rear end, wheel diameter, etc.) When you do factor it in, you arrive at the horsepower figure.

[TedSla]

The answer is yes.

Example: I built original FF 1600s 30 years ago; not the Kent Unrated version. Why? They had lighter total valve gear weight, higher compression, and could build gobs of torque. With the correct gearing a driver could leave Turn 3A at Seattle International Raceway, and pull unrated-powered cars one car length per each gear before braking for Turn 4. Add in the two other like sections before heading onto the straight, and you had an insurmountable lead.

Same set of circumstances applied to Laguna Seca and the old Westwood track in Vancouver BC. Remember, a road course is a series of drag races with an occasional straight thrown in.

And with a few changes we held off the unrated on longer tracks...but I'm not going to tell you what the changes were!

[Mobil1NSXR]

Originally posted by TedSla
The answer is yes.

Example: I built original FF 1600s 30 years ago; not the Kent Unrated version. Why? They had lighter total valve gear weight, higher compression, and could build gobs of torque. With the correct gearing a driver could leave Turn 3A at Seattle International Raceway, and pull unrated-powered cars one car length per each gear before braking for Turn 4. Add in the two other like sections before heading onto the straight, and you had an insurmountable lead.

Same set of circumstances applied to Laguna Seca and the old Westwood track in Vancouver BC. Remember, a road course is a series of drag races with an occasional straight thrown in.

And with a few changes we held off the unrated on longer tracks...but I'm not going to tell you what the changes were!

Thanks for sharing your experience, but that is assuming all the others handled the same? I still need an answer to why the NSX blew two torque monsters away. It lacked at least 180 lb/ft, which is more than enough to get a few car lengths against other cars, all other things being equal.

Right now I can only assume that the NSX enters and leaves corners with so much more speed that it is insurmountable despite extra torque (Just imagine how many car lengths it leaves the corners with). The NSX also had the benefit of superior aerodynamics to cut through the air better, a characteristic of the car, not the engine.

The Mugen engine's HP must also be a bit friskier then the other two, allowing for mad acceleration, despite less peak torque (I suppose they do gear them to reach approximately the same top speeds), so the accelerative qualitites of all the engines are similar, torque or not. Don't forget just how much heavier the NSX is too. And that is why IMHO, torque doesn't matter as much as chassis capability (handling) in this modern era.

[TedSla]

Once the cars were out of the corner and going straight, handling had nothing to do with the acceleration gap. Parenthetically, we could power through and exit a corner with less wheel spin and better control than the others, especially very low speed corners.

Here’s a clue: Generally speaking, toque-oriented engines have a flatter horsepower curve. Our Original engine may have had equal to less maximum horsepower than a higher revving engine, but they had more horsepower at lower RPM ranges. So you have a “flatter” power curve and, to use the FF example, at 4500 RPM a lot more horsepower on the meter than the peaky Uprated engine. We referred to it as “lifting the tail of the power curve.”

And that’s what drove the vehicle forward…

[Mobil1NSXR]

Originally posted by TedSla
Once the cars were out of the corner and going straight, handling had nothing to do with the acceleration gap. Parenthetically, we could power through and exit a corner with less wheel spin and better control than the others, especially very low speed corners.

Here’s a clue: Generally speaking, toque-oriented engines have a flatter horsepower curve. Our Original engine may have had equal to less maximum horsepower than a higher revving engine, but they had more horsepower at lower RPM ranges. So you have a “flatter?power curve and, to use the FF example, at 4500 RPM a lot more horsepower on the meter than the peaky Uprated engine. We referred to it as “lifting the tail of the power curve.?

And that’s what drove the vehicle forward?

Yes, but I'm asking which actually wins more races. At Monza of course, the NSX would probably lose a bit on the straights.

What I'm trying very hard to say is that Handling will allow u to leave the corner with such a gap that all that extra torque/power of the car behind won't get back even on the straight. Hey, if 180 lb/ft extra doesnt a winner maketh...

I'm also trying to say that Mugen's engine design clearly made up for a lack of torque by having very frisky horses. The accelerative gap btw an engine with higher HP and one with almost 180 lb/ft more torque (more than all my car has) were distinctly...not so great, probably not even 1 car lengths on the flat mile long straight.

A car that handles A LOT better, and accelerates the same without having all that much torque proves to me that there are more solutions than torque.

Thats is very clearly why the Williams has not beaten the Ferrari despite its extra power these past few years.

[TedSla]

What wins races is putting a two second margin against whoever's behind you at lap times close to qualifying times. Then number two et al has to be a half-second+ under qualifying time four laps in a row to come even with you.

They usually fall off the track trying...

Starting to make more sense? Does it look like a current example in F1?

[Mobil1NSXR]

Originally posted by TedSla
What wins races is putting a two second margin against whoever's behind you at lap times close to qualifying times. Then number two et al has to be a half-second+ under qualifying time four laps in a row to come even with you.

They usually fall off the track trying...

Starting to make more sense? Does it look like a current example in F1?

Yeah it does make sense that torque makes a driver's life easier, but it doesn't mean its the be all and end all of racing.

I've seen many examples which back up my claim, JGTC is one, Speed Touring is another. From 1999-2002 the Acura R's won back-to-back titles on the strength of their handling, their 1.8 liters in no way superior to the 2.8 - 3.2 liter BMW's.

Handling and chassis ability has shown itself time and time again. When an engine tuner finds a way to accelerate with the same gusto without the same torque, that is also something I really like.

[TedSla]

Re: ...but it doesn't mean its the be all and end all of racing.

No, it's not the end all. And I made it clear in my first post - long tracks required a different setup. And that meant changes to the engine, gearing, and chassis. But, on the back-side, we could still pull out one-half second in the first lap at, say Portland, and the rest had to have divine intervention to catch up.

[Mobil1NSXR]

Originally posted by TedSla
Re: ...but it doesn't mean its the be all and end all of racing.

No, it's not the end all. And I made it clear in my first post - long tracks required a different setup. And that meant changes to the engine, gearing, and chassis. But, on the back-side, we could still pull out one-half second in the first lap at, say Portland, and the rest had to have divine intervention to catch up.

Call me a stubborn little prick, but what I am comparing is two different types of car. Your example is of similar cars, but one with a setup advantage that gave it more torque. In that case, yes I totally agree with you that torque matters.

TedSla, I'd like to hear your comments on my examples please?

[TedSla]

Okay, here's a clue: Let's take for example the 2001 JGTC series,... Where it suffered was going uphill.

The engine doesn't have any low-end power or torque and the vehicle carries a 110 lbs penalty.

A stump puller she ain't, but probably real sweet on the long, flat straight.

[Mobil1NSXR]

Originally posted by TedSla
Okay, here's a clue: Let's take for example the 2001 JGTC series,... Where it suffered was going uphill.

The engine doesn't have any low-end power or torque and the vehicle carries a 110 lbs penalty.

A stump puller she ain't, but probably real sweet on the long, flat straight.

Yeah it was real sweet. So as the winner of the championship, the handler is better? And to say it had no torque at the bottom end is probably inacurate. The VTEC system makes sure there is ample low range torque to work with.

There are many more examples of TOrque vs. handling. F1 vs. CART comes to mind. CART had 2.65 liter turbos belting out between 800-1000 hp, and who knows how much torque back then? Comparatively speaking, Alex Yoong would have lapped Da Matta the same year. F1 handles a lot better, but CART has a lot more torque.

How bout we compare the Honda and Ducati MotoGP machiines? The Honda handles real sweet and is great coming out of corners, but the Ducati had mad power/torque. Who won then?

Well, anyway let's look forward to a great San Marino GP!

[Greg Locock]

I'm staying out of power vs handling

Here's a few configurations of engines, some of which stick to 3 litres, and then some demonstrate that for a given conrod design for an F1 engine you really need as many cylinders and as big a capacity as you can.


Name,NoCyls,Cap cc,Bore mm,stroke mm,redline rpm,power(hp),cyl cap cc
3 litre engines,8,3002,99,48.8,17150,804,375
BMW V10,10,3002,99,39.0,19200,900,300
,12,3002,99,32.5,21000,984,250
,14,3002,99,27.9,22680,1063,214
,16,3002,99,24.4,24250,1137,188

Big V8s,8,4803,99,78.0,13560,1017,600
,8,6097,99,99.0,12050,1147,762
half speed,8,9791,99,159.0,9500,1452,1224

450 cc/cylinder,10,4503,99,58.5,15650,1100,450
,12,5404,99,58.5,15650,1320,450
,14,6304,99,58.5,15650,1541,450
,16,7205,99,58.5,15650,1761,450

,12,2771,99,30.0,21850,945,231

You'll have to cut and paste that into a spreadsheet to make sense

Assumption is that VE*fuel efficiency is a constant, in reality the latter probably favours long stroke and slower engines.

[kos]

Originally posted by Greg Locock

Name		NoCyls	Cap 	Bore 	stroke 	redline power	cyl cap

			(cc)	(mm)	(mm)	(rpm)   (hp)	(cc)

3 litre engines	8	3002	99	48.8	17150	804	375

BMW V10		10	3002	99	39	19200	900	300

		12	3002	99	32.5	21000	984	250

		14	3002	99	27.9	22680	1063	214

		16	3002	99	24.4	24250	1137	188



Big V8s		8	4803	99	78	13560	1017	600

		8	6097	99	99	12050	1147	762

half speed	8	9791	99	159	9500	1452	1224



450 cc/cylinder	10	4503	99	58.5	15650	1100	450

		12	5404	99	58.5	15650	1320	450

		14	6304	99	58.5	15650	1541	450

		16	7205	99	58.5	15650	1761	450



		12	2771	99	30	21850	945	231

[Mobil1NSXR]

Originally posted by Greg Locock
I'm staying out of power vs handling

Here's a few configurations of engines, some of which stick to 3 litres, and then some demonstrate that for a given conrod design for an F1 engine you really need as many cylinders and as big a capacity as you can.


Name,NoCyls,Cap cc,Bore mm,stroke mm,redline rpm,power(hp),cyl cap cc
3 litre engines,8,3002,99,48.8,17150,804,375
BMW V10,10,3002,99,39.0,19200,900,300
,12,3002,99,32.5,21000,984,250
,14,3002,99,27.9,22680,1063,214
,16,3002,99,24.4,24250,1137,188

Big V8s,8,4803,99,78.0,13560,1017,600
,8,6097,99,99.0,12050,1147,762
half speed,8,9791,99,159.0,9500,1452,1224

450 cc/cylinder,10,4503,99,58.5,15650,1100,450
,12,5404,99,58.5,15650,1320,450
,14,6304,99,58.5,15650,1541,450
,16,7205,99,58.5,15650,1761,450

,12,2771,99,30.0,21850,945,231

You'll have to cut and paste that into a spreadsheet to make sense

Assumption is that VE*fuel efficiency is a constant, in reality the latter probably favours long stroke and slower engines.

So which do you prefer?

[McGuire]

Originally posted by Dmitriy_Guller
When people talk of engine torque, they're missing half the picture. Engine torque is meaningless without factoring final drive torque multiplier (from gearbox, rear end, wheel diameter, etc.) When you do factor it in, you arrive at the horsepower figure.

True, if you have an infinite number of gears in the transmission and the car is somehow always in the correct gear. If your transmission is something less than that, engine torque is important. The more slow corners the course has, the more crucial engine torque becomes. As Carroll Shelby used to say, "Horsepower sells cars. Torque wins races."

[Greg Locock]

Thanks kos, how did you do that?

"So which do you prefer?"

Anyway, the answer, with the assumptions I made, is:

" for a given conrod design for an F1 engine you really need as many cylinders and as big a capacity as you can."

Now, I don't have the faintest idea whether conrod/piston design is the hardest bit for F1, but I know that for production engines it causes more strife than most things.

[sblick]

I think I can provide a good example. In the 80's Jack Roush ran in IMSA GT. He had a turbo 4 cylinder and a 5.7 liter V-8 for his Merkur XR4ti (I think Ford Sierra in Europe). On the street courses he used the V-8. Lots of tourque making the car quick out of the corners to the next corner. On the road courses he used the turbo 4 so the car had more top end from more horsepower but less torque. So essentially the car is exact in suspension setup and weight but had two different engines for two different tracks. This kind of shows that it depends on the situation to what you want for an engine. A long open track like F1 give me lots of horsepower. Put me on a short course with torque.

[McGuire]

Originally posted by TedSla
The answer is yes.

Example: I built original FF 1600s 30 years ago; not the Kent Unrated version. Why? They had lighter total valve gear weight, higher compression, and could build gobs of torque. With the correct gearing a driver could leave Turn 3A at Seattle International Raceway, and pull unrated-powered cars one car length per each gear before braking for Turn 4. Add in the two other like sections before heading onto the straight, and you had an insurmountable lead.

Same set of circumstances applied to Laguna Seca and the old Westwood track in Vancouver BC. Remember, a road course is a series of drag races with an occasional straight thrown in.

And with a few changes we held off the unrated on longer tracks...but I'm not going to tell you what the changes were!

Quite so. The result has played out countless times...

At Laguna Seca there is a turn which it is impossible to gear a champ car for -- all you can do is chug off the corner at 6500 rpm in first gear as best you can. Since everyone was running an essentially similar package it wasn't a huge problem...or at least it was about the same for everyone. But as I was watching this, sometimes I couldn't help picturing an Atlantic car blasting through the entire parade on the inside.

In the mid 1980's the torque curve and driveability of the typical champ car engine was so bad that some teams (Penske, Truesports) took to building special cars for the tight road courses like Laguna and Mid-Ohio, powered by small block Chevrolets. This required essentially rebuilding the car from the bulkhead back, and produced too many compromises in the chassis and aero to make it worth the trip. What they needed was basically a different car, which couldn't be economically justified for only part of the schedule. But boy did these things get off the corners good. At about that time Gurney's Eagles were also running stock blocks, and that was one of their strengths.

[Croaky]

I once saw a club race with various hugely different types of car. It was fantastic. There were 500bhp Ford Sierra Cosworths, all chirping and hissing turbos, and the drivers were pretty certain they were going to disappear into the distance. In the race, they were all destroyed by a tiny little fibreglass sportscar with 200bhp, though the power to weight ratios were surprisingly similar. It was a tight, twisty track where the little sportscar won out on handling and power delivery, even though it lost out on top speed to the big Fords, several of which flew off the track in frustration.

[McGuire]

Let's see here, an unlimited displacement F1 engine to fit in existing chassis...first thing is to get rid of the DOHC four-valve setup and turn all that weight and bulk on top into cubic inches. Those 12 oil pumps etc. have to go, and the variable intake trumpets as well. Midrange power will not be a problem here LOL.

I propose a V10 of 110mm bore and 91.5mm stroke, for a displacement of 8.7 liters. It employs a single camshaft mounted high in the block, with rollerized finger followers pivoting on a longitudinal shaft just above (ala Cummins Diesel copied in the Ilmor Indy engine etc.) This will permit extremely short and stiff pushrods to operate the rocker arms and 2 valves per cylinder (62mm intake, 50mm exhaust) in a canted/splayed chamber layout. Pneumatic valve springs of course -- that's a rather large intake valve.

Looking over the various velocities etc and referring to the experience base with components of similar proportions, I believe this engine would be good for a reliable 9500 rpm. If BMEP in the range of 13.5 BAR can be achieved, which is very realistic for an engine of this speed and valve area, it ought to be good for an easy 1250 hp. Roughing out the combination with a wild guess at cam timing etc. and running it through the old Dynomotion dyno sim, this engine makes 1324 hp at 9000 rpm. And it also makes over 800 lb ft of torque from 5000 rpm on, and a peak of 860 lb ft. Ye old torque curve is as flat as an anvil.

While 1324 hp sounds like a lot (and it is) here it requires a specific output of only 152 hp/liter, which is not all that difficult...in the range of current street bikes. NASCAR engines produce 135 hp/liter with extremely limiting valvetrain and port volume rules and an old four-barrel carb. Meanwhile, some rough sketching shows this engine might be only a few inches longer than the current F1 package, approximately the same width, and maybe even a little shorter in height. Weight and CG are rather difficult to estimate, but I don't think they would be a problem. Tossing the DOHC setup lowers the CG considerably, while weight-wise, this here motor consists mainly of ten tall, wide holes.


And to think I spent nearly an hour on this stupid idea...

[RDV]

mcguire-I propose a V10 of 110mm bore and 91.5mm stroke, for a displacement of 8.7 liters.

...sounds like a Chrysler Viper engine..... are you sure?;)

[Dmitriy_Guller]

Originally posted by McGuire


True, if you have an infinite number of gears in the transmission and the car is somehow always in the correct gear. If your transmission is something less than that, engine torque is important. The more slow corners the course has, the more crucial engine torque becomes. As Carroll Shelby used to say, "Horsepower sells cars. Torque wins races."

What you're really talking about is how flat the horsepower curve is, or how horsepower is spread over the rev range. If you race at Monaco, you want to have good horsepower over a wide rev range. If you race IRL car on 1.5 mile oval, then you're spending all of your time near the redline, so you want to bunch as much horsepower as you can into the narrow band.

[McGuire]

Originally posted by Dmitriy_Guller


What you're really talking about is how flat the horsepower curve is, or how horsepower is spread over the rev range. If you race at Monaco, you want to have good horsepower over a wide rev range. If you race IRL car on 1.5 mile oval, then you're spending all of your time near the redline, so you want to bunch as much horsepower as you can into the narrow band.

You are stuck in a semantical ground loop. The force created on the crown of the piston and translated by the crankshaft to drive the wheels is torque.

Torque = MEP x CID / 48 pi

Horsepower is merely torque over time.

HP = torque x 5252 / rpm


Returning to your previous post, there is an error which I should have corrected.

"Engine torque is meaningless without factoring final drive torque multiplier (from gearbox, rear end, wheel diameter, etc.) When you do factor it in, you arrive at the horsepower figure."

Gears ratios do not multiply horsepower. They can only multiply torque.

[McGuire]

Originally posted by RDV


...sounds like a Chrysler Viper engine..... are you sure?;)

Yeah, sounds like it huh. Actually the Viper V10 is good for 800 easy hp if not saddled with air restrictors. Anyway, the Viper is an adaptation of a truck engine which was itself a 10 cylinder variant of the old LA V8 designed way back in the 1960s. Here we are talking about a purpose-built engine...aside from the displacement and number of cylinders there is really not much of a resemblance.