190 replies to this topic

[McGuire]

Originally posted by imaginesix
I say you're both wrong.

That's ok, I don't agree with any of you.

Actually, Engineguy and I are close to being on the same page, we probably differ mainly in explanation.

[Greg Locock]

I'm not puzzled by the three wheeler now.

[Engineguy]

Originally posted by Greg Locock
I'm not puzzled by the three wheeler now.

Cool. Now you can build that Chevy trike ya always wanted.

[McGuire]

Now I'm puzzled.

[Ross Stonefeld]

I'm just concerned.

[McGuire]

That totally screws my theory that a smallblock Chevy will fix anything.

[McGuire]

Advantages to this design... with that much understeer, at least you will have a good long look at what you are about to run into. And the generous power-to-weight ratio ensures that you will never be late arriving at the scene of the accident. You should beat the ambulance there by a good 30 minutes.

[eldougo]

[imaginesix]

Originally posted by McGuire
That's ok, I don't agree with any of you.

Great. Now that we all disagree, we can move on the the next question: Is the torque reaction from the engine at a fixed speed sufficient to have a noticeable impact on grip (ie passing "3 and 4 cars a lap"), or would such a performance improvement only come by the much more significant force (as observed by messing around with an electric drill) of an accelerating engine?

Keeping in mind, any load transfer improvement from the force of the engine rotation is doubled since the standard engine configuration works to the car's disadvantage, and considering the fact that with increased grip comes increased throttle opening and therefore even further improvements in grip, allowing even more throttle, further improving grip... ... ...

On this question, I can guarantee not to disagree with anyone!

[Powersteer]

The only reason why acceleration seem to produce more twist is because its when more throttle used. On a top speed run, maximum horsepower is twisting the engine against its bushings but like Engineguy said, 1st gear has the most chassis torque. This situation differs if its a front engine-rear gearbox layout where the twisting strength is the other way around?

Originally posted by imaginesix
there is just as much lateral load transfer on a solid axle as on an independent suspension driveline

I agree. From driveshaft to engine. In fact maybe it would twist even more because it has more friction than a solid axle so more power is needed for the same performance. Like you, I too am waiting to be shot down.

[Greg Locock]

Propshaft torque is say 500-1000 Nm. If that is reacted at the CP then the force is around 300-600N, or 75-150 lbf at each wheel.

Yes that would be significant.

If...

[imaginesix]

500-1000Nm output just to maintain a steady speed? I can see that much torque happening at full throttle only, which was kind of the point of the question.

[McGuire]

Originally posted by imaginesix
Great. Now that we all disagree, we can move on the the next question: Is the torque reaction from the engine at a fixed speed sufficient to have a noticeable impact on grip (ie passing "3 and 4 cars a lap"), or would such a performance improvement only come by the much more significant force (as observed by messing around with an electric drill) of an accelerating engine?

Not really, which is why reverse-rotation engines have never caught on in all these years. Obviously, in road racing there is no point, while in oval racing (all left turns) it looks like it could potentially make a difference.

Instead of lifting the LF tire on corner exit out the reverse-rotation setup will plant the LF, so it looks all trick and fast. So over the years a lot of romance, mystery and folklore have surrounded the deal. But when all is said and done it does not make much of a difference in lap times, because it does not improve forward bite to any significant degree. (It does not remove or reduce the moment across the rear axle; it only reverses the moment across the engine mounts.) If it really did work, it would have become the way to go in oval racing at some point. Enough people have tried it. But it doesn't, so it never did.

[McGuire]

Maybe it would help if we took it one step at a time.

If we have a moment arm and a force we have a torque, irrespective of acceleration.

Here we have angular force fed into a lever arm or moment

a) between the crankshaft and engine mount, and

b) across the rigid housing of a live rear axle.

The engine is bolted rigidly (more or less) to the chassis. However, the rear beam axle and its pair of tires are essentially just laying on the ground. All that prevents the entire assembly from rotating around the differential pinion when you apply torque to the driveshaft is the weight of the vehicle, acting through a pair of springs. So when you apply torque it is going to load one tire and unload the other.

And no, you don't have quite this problem with IRS. You have the same forces to be sure, but here the differential housing is not laying on the ground. It is is bolted right to the chassis. And we don't have a rigid beam connecting the left wheel to the right wheel. We have a pair of articulated driveshafts with universal joints. No lever arm.

As Mr. Locock shrewdly calculated, this force is significant but not huge. The precise magnitude of a live axle's reaction torque and its effect on tire loading and longitudinal grip is dependent on track width, CG, engine torque, wheel and roll rates, grip coefficient, gearing, and mass among a bunch of other things, so an accurate calculation of its effect can get a bit complicated, but as a rough rule of thumb... On your typical V8/rwd American performance car the resultant force is very roughly equivalent to ~100 lbs of normal force. In other words, if you are trying to optimize such a car for the dragstrip, you can usually fix it and make the car launch perfectly straight and even with somewhere around 100 lbs of ballast or static preload on the right rear.

[imaginesix]

Originally posted by McGuire
If we have a moment arm and a force we have a torque, irrespective of acceleration.

I'm sure you meant 'irregardless'.

BTW, in the spirit of disagreement, I disagree that reverse-rotating engines would be prevalent in roundy-round racing if they provided a performance advantage, for the same reason that carbon fiber unibodies and fuel injection are not prevalent even though they would provide benefits. Especially since the effect is doubled (~100lbs is returned to the outside wheel, plus ~100lbs added from the counter-rotating engine).

Though I kinda see now that the effect of an accelerating engine is only different from a steady-rpm engine in proportion to their different output, though it didn't feel that way when messing around with my drill.

[McGuire]

Originally posted by imaginesix
I'm sure you meant 'irregardless'.

BTW, in the spirit of disagreement, I disagree that reverse-rotating engines would be prevalent in roundy-round racing if they provided a performance advantage, for the same reason that carbon fiber unibodies and fuel injection are not prevalent even though they would provide benefits. Especially since the effect is doubled (~100lbs is returned to the outside wheel, plus ~100lbs added from the counter-rotating engine).

Though I kinda see now that the effect of an accelerating engine is only different from a steady-rpm engine in proportion to their different output, though it didn't feel that way when messing around with my drill.

Ace, irrespective is a real word while irregardless is not.

My point about the success of reverse-rotation engines in oval short-track cars is simply this: every five or ten years someone tries it somewhere, and finds nothing. People have been trying it since the 1930s at least, and getting nowhere. It's not for lack of trying but lack of results. Take a look at this:



By the way, fuel-injection has been standard in sprint cars since early '50s (when most F1 cars were still using Webers and Meminis) and make extensive use of cf, mag and ti in their construction. Just not in their frames, which are chrome-moly steel due to all the maintenance required. They race several times a week and crash frequently.

[imaginesix]

Originally posted by McGuire
Ace, irrespective is a real word while irregardless is not.

I disagree.

[McGuire]

Originally posted by imaginesix
I disagree.

What do you disagree about?

[Engineguy]

Originally posted by imaginesix
I disagree.

Regardless of your disagreement, you ain't not incorrect.

[imaginesix]

I've become desensitized to my faults.

[McGuire]

I'm sorry, this is abuse. Arguments are down the hall.

[dosco]

Originally posted by imaginesix
I've become desensitized to my faults.

You can't feel your asscrack?

[imaginesix]

Are you sure you want to know the answer to that question?

[Breadmaster]

First cheating then upside down engines and torque then finally incomprehensible bo!!ocks.

where is this once fine thread going?!!

[RDV]

...its gone allready.... irregardless ;) of this , there is an interesting book by Tom Jensen "Cheating"(ISBN 1-893618-22-6), which covers examples in Nascar...but the most interesting one is Smokey Yunick's "Best damn garage in town"(ISBN:0-9724378-3-5), with his often hilarious descriptions of stock car racing in the US from 1938 to 2000...no foreword, but a foreskin, and the "Dictionary according to Smokey" at the end decidedly non-PC

[zac510]

I think you may have just saved the thread with that unirrelevant book information. Thanks for the tip ;)

[McGuire]

Originally posted by Breadmaster
First cheating then upside down engines and torque then finally incomprehensible bo!!ocks.

where is this once fine thread going?!!

Come now, it wasn't that good.

[Breadmaster]

Originally posted by RDV
...its gone allready.... irregardless ;) of this , there is an interesting book by Tom Jensen "Cheating"(ISBN 1-893618-22-6), which covers examples in Nascar...but the most interesting one is Smokey Yunick's "Best damn garage in town"(ISBN:0-9724378-3-5), with his often hilarious descriptions of stock car racing in the US from 1938 to 2000...no foreword, but a foreskin, and the "Dictionary according to Smokey" at the end decidedly non-PC

oooh! nice one.

I'll add to my birthday list......

[gas28man]

It's an arguable point that reverse-rotation won't gain you much in lap times. I have nothing to prove it one way or the other. But from my friend's experience, it may not have mattered. The gain came from doing something that every other car in the field wasn't doing. So while every other car on the track is braking/coasting/feathering through the corners, the reverse-rotation car is on the gas, handling better, and making passes.

So why doesn't everyone do it? Well, in my experience, racecar builders are a risk-averse lot (unlike the drivers). Engine-building is a business, and you have something to lose if you try something new and it gets you to running at the back of the field. You also have to have a significant R&D budget to test something totally outside the envelope if you haven't already got a good idea that it will yield results.

Plus reverse-rotation requires a lot of one-of-a-kind features -- mounting the quick-change upside down, plumbing the cooling and oil systems (remember, the Corvair was air-cooled, eliminating the water issue, at least), not to mention, adapting a unique driving style.

It requires an integration of three different disciplines -- engine building, chassis building, and driving -- that in most touring series have become modular. You buy your chassis one place, your engines in another, and you put whatever shoe is available in the seat. The three never talk to each other, except through the crew chief, who is perhaps the most risk-averse of all of them.

Consider, too, that in the early 70s, when my friend ran it, there was a greater diversity of engines, chassis, teams and drivers in midget racing, and the rulebook wasn't as thick as it is today. (When I first started racing street stocks in the early 80s, my rulebook was a single sheet of paper!!). Guys tried everything -- Cosworths, Offys, Corvairs, VWs, boat engines, motorcycle engines, snowmobile engines, you name it. Today, there are just a handful of midget chassis builders, and an only slightly larger number of engine builders. Safety has something to do with this, by the way. By making chassis more restricted, to assure safe construction, you're also consolidating the potential number of companies with the wherewithal to build one. Everyone has the same stuff, more or less, and everyone knows what everyone else has got, for the most part.

A lot of times, it's just easier to follow the herd, run what you know works, and try to gain an advantage through more conventional means (better setups or proven cheats).

[jmorris]

Penske? See both Penske IRL Dallaras have rear wing supports collapse during the Milwaukee race? I guess they had too much "flex" built into the things. Remember this is supposed to be a "spec" chassis. IRL double-talk about authorized changes - Penske replaced carbon fiber with aluminum for the vertical wing supports. Hmmm! IRL is supposed to be budget controlled through equipment restriction - what that really means (unlike F1) you can cheat but you don't get to test it for reliability first. The IRL/Penske PR machines have nicely swept this away - the motorsports press is silent, afraid or simply likes the free Marlboros?

[Fat Boy]

I'd love to find fault there, but I really don't think there is.

Wing supports are open. I believe they just under built them, probably saving weight. Milwaukee isn't a place where you'd flex the wings back to reduce drag. There is a minimum wing angle allowed in the IRL, but everyone runs Max at Milwaukee.

One thing I did find interesting. They used Rick Reineman in the press to say, "We f'd up". Rick is a chief mechanic. The coverage on TV showed the wing mount bolts still solidly in place. It wasn't an error of his to apologize for. It was an engineering problem, which leads you to others. These 'others' were very, very quiet.

Cheating? I don't think so. Scapegoating? That's what it looks like to me.

[Ross Stonefeld]

I've seen Rick on TV a bunch of times. Is he maybe the default talking head after Penske/Cindric when it comes to things that happen to the car?

The only other Penske feller I remember on TV was a tire changer at Mid-Ohio in 98 after he got clipped by someone in the pitlane. He was going a bit long, but nothing was going on, until Andretti tumbleweeded down the backstraight on the picture-in-picture and Gerould had to cut away quickly and politely.

[Fatgadget]

Not sure if this one qualifies as a cheat...A driver banks a flier during qualifying. Immediately dives into the pits, comes out and liberally sprinkles the ideal line with oil from a deliberately overfilled oil catch tank!..neat eh!

[alexbiker]

Yup. That would be Brundle in the Tyrrell. He admitted it on air.

[RDV]

...comes out and liberally sprinkles the ideal line with oil from a deliberately overfilled oil catch tank

....even more diabolicaly, in BTCC and Superpole, do your run , and then flick switch that actuates windshield washer motor, which then liberaly sprinkles track with oil on your slow down lap.... was used at least 5 times till the organizers, pressurised by the other teams, informed the suspects that the next time the track was FUpped after their run they would lose all their times and start from back of grid.... funny , never happened again....;)

[John B]

What is the concensus on Jordan in 1999? I remember TC and other rumors discussed in threads years ago - there were references to 'two teams that were under suspicion that year.'

I'll give you a historical one I always thought was kind of random - Derek Warwick's charge into second place past Pironi's Ferrari with the Toleman in the 1982 British GP at Brands before stopping on course. Though the team started to look good in late 1983, I don't think they came remotely close to points in any other 1982 race (they were coming off qualifying only twice in '81).

[canon1753]

Wasn't the Toleman on half tanks and really soft tyres to look good? That is what I seem to remember. I could very much be wrong.

The thing with Turbos is that you could turn the screw up to get extra hp. The motor would pop or the turbo would fail or whatever. It wouldn't be cheating unless there were boost limits. And you'd look good for however many laps....

[RDV]

canon1753-Wasn't the Toleman on half tanks and really soft tyres to look good? That is what I seem to remember. I could very much be wrong.

Yes, not a cheat....when I asked the Pirelli blokes on the grid why they were on medium qualifiers and we had been recommended hard race tires, they said, "dont worry, low tanks and will be in in ten laps".... looked good for a while....;)

[murpia]

Originally posted by John B
What is the concensus on Jordan in 1999? I remember TC and other rumors discussed in threads years ago - there were references to 'two teams that were under suspicion that year.'

http://www.grandprix.../gpe/rr644.html
Maybe some of you will remember the massive shunt at the race start or the Europe GP at the Nurburgring, triggered when Hill's engine cut about 10 seconds after the start. Diniz was a lucky man as the roll-hoop broke off his Sauber. Later, Frentzen's engine cut at almost exactly the same point on the track, about 10 seconds after a pit stop.

This was during the period when launch control was banned. Anti-stall was permitted, but unless the driver pulled the clutch lever within 10 seconds of anti-stall kicking in the engine would be cut.

Not that I'm implying anything...

Regards, Ian

[cheapracer]

Originally posted by McGuire



My point about the success of reverse-rotation engines in oval short-track cars is simply this: every five or ten years someone tries it somewhere, and finds nothing. People have been trying it since the 1930s at least, and getting nowhere. It's not for lack of trying but lack of results. Take a look at this:

.

A different world I agree but interesting anyhow is that BMW motorcycles (flat twins, inline with the bike crank) found success at Daytona years ago including using reverse-rotation engines specifically to pull the bikes down thru the banking.

[cheapracer]

Allan Moffat introduced a Mazda RX7 to the Australian Touring Car series in 1981. There was some dispute at the time over the fact that it was left hand drive in a right hand drive country which gave some advantage as most tracks in Australia are counter clockwise.