German Engineering

[Syntyr]

Remember reading about 30 years ago an article in one of the car mags. Made the point that CA had the most Porsches of any states, and since the majority of them were purchased by doctors, dentists, and lawyers who had no clue how to handle tail-heavy oversteer, fully 70% of them had crashed going backwards.

Been bite by that! I was driving a 1977 911 with a gray market 88 turbo engine in it. That car was light and wicked fast. Was going around a right hand corner and I had just shifted into second. Thankfully I wasn't going all that fast, right around 50. It was feeling nice and tight not near oversteer yet so I thought I would add some more power to kick the rear end out a little so I could get it do dig in and come out of the corner faster.

Well I forgot about that big turbo spinning or should I say not spinning and its lag time to get up to speed!

Just about to exit the turn and the car finally had gotten up to 2300 rpm and that's when the turbo finally spooled up. It then proceeded to dump an extra ~140 horsepower to the rear wheels and thats all she wrote! I froze and the next thing I knew I was going BACKWARDS and then the rear tires finally bite in to the asphalt enough to stop spinning and all of the sudden I was going forward again!

That's when I figured out I didn't have the reactions to be a race car driver! I wish I hadn't had to sell that car. One day I will get another one!

[jimlongley]

[youtube]http://youtube.com/watch?v=VqZO-xURLqc[/youtube]

More Herman Engineering

Cool.

Sawing at the wheel too much.

Rear engine Porsches are famous for being tail happy at the outer performance limits, and that sawing at the wheel is what it takes in those particular cars to keep reeling the back end back into line. Other cars do it too, but the weight of the rear engine, a large part of which is aft of the rear axle, makes the tendency more pronounced than in mid-engine or front-engine cars. Front-engine cars tend to understeer and push the front end, and so you have to deliberately spin the back tires to get the back end crossed up and stepped out a little bit to tighten up the turn. Mid-engine cars tend to be perfectly balanced. Rear engine cars tend to oversteer and lose the rear end easily, and so you're in a constant state of countersteering at the limits to offset the rear swinging out. The problem is that countersteering demands even more throttle application to keep the back end tracking outside the countersteered front end, and then while you're under throttle, the front end gets light and starts to push, which in turn requires more tail antics and aggressive steering techniques. So Porsches are known to produce these long lurid slides in which the driver is constantly sawing back and forth between countersteering and oversteering to keep back end tracking and the weight balanced between front and rear.

You tend not to see it as much during an actual race because racing in traffic causes speeds to drop a bit as there is less room to maneuver in, and the drivers get more cautious in order avoid collisions. But on an open track day in perfect weather like in this video, with no other cars in the way, the driver can use the track edge to edge, and cornering speeds are a lot higher......hence the long smokey slides. The same driver in the same conditions in a different car would likely produce less drama.

I understand all that, especially having had a '65 Corvair with the Spyder package and raced it a little , but he was sawing too much, in a couple of parts of the video you can see his hands from outside, and he's sawing away without being in a slide, or even in a turn.

BTW, the only time I ever did an end for end swap in my Corvair was during an ice storm and I hit the top of a slight hill with a dogleg to the right and reverse camber. I did a full 360 and came out back on my side of the road (after a carom off the opposite curb) going the right direction. Although I was probably only doing 15 to 20 mph, it still happened so fast I only had just time to react. Glad that nobody was crazy enough to be trying to come up the hill.

[The Annoyed Man]

Rear engine Porsches are famous for being tail happy at the outer performance limits, and that sawing at the wheel is what it takes in those particular cars to keep reeling the back end back into line. Other cars do it too, but the weight of the rear engine, a large part of which is aft of the rear axle, makes the tendency more pronounced than in mid-engine or front-engine cars. Front-engine cars tend to understeer and push the front end, and so you have to deliberately spin the back tires to get the back end crossed up and stepped out a little bit to tighten up the turn. Mid-engine cars tend to be perfectly balanced. Rear engine cars tend to oversteer and lose the rear end easily, and so you're in a constant state of countersteering at the limits to offset the rear swinging out. The problem is that countersteering demands even more throttle application to keep the back end tracking outside the countersteered front end, and then while you're under throttle, the front end gets light and starts to push, which in turn requires more tail antics and aggressive steering techniques. So Porsches are known to produce these long lurid slides in which the driver is constantly sawing back and forth between countersteering and oversteering to keep back end tracking and the weight balanced between front and rear.

Well played! Better description than I have ever given regarding this! Well Played!

Thank you. FWIW, I never raced cars, but I did roadrace motorcycles for several years, and most of the principles are the same.....and the fastest way around a tight corner back then was crossed up and spinning the back tire, then feeding the traction back in as you come off the apex. And even in a fast sweeper, if you've used up all the available lean angle to make the turn, then the only way to pick up speed is the slide the back end. But I did spend a lot of time around car racers back then, including a few Porsche drivers. When they told me the driving mechanics of a Porsche, I understood it right away because bikes have the same problems as cars, just in a lighter package with smaller contact patches that accelerates even faster.

One exception.....if you see a bike racer "sawing back and forth" at his handlebars, he's not steering the bike, it's steering him, and it's called a "tank-slapper."

[Syntyr]

Thank you. FWIW, I never raced cars, but I did roadrace motorcycles for several years, and most of the principles are the same.....and the fastest way around a tight corner back then was crossed up and spinning the back tire, then feeding the traction back in as you come off the apex. And even in a fast sweeper, if you've used up all the available lean angle to make the turn, then the only way to pick up speed is the slide the back end. But I did spend a lot of time around car racers back then, including a few Porsche drivers. When they told me the driving mechanics of a Porsche, I understood it right away because bikes have the same problems as cars, just in a lighter package with smaller contact patches that accelerates even faster.

One exception.....if you see a bike racer "sawing back and forth" at his handlebars, he's not steering the bike, it's steering him, and it's called a "tank-slapper."

Yeah you say they are the same... No thank you! The first time I went 100+ on a bike it got skitty on me and we were dancing all over the road until I got it slowed back down. That was also the LAST time I went fast on a bike. Entirely different situation with everything just hanging out in the air sitting on a bike. Don't get me wrong I still like to ride but I do it "doucement"!

These guys are certifiably INSANE - Isle of Man TT race. 200 mph on a bike. Nope! http://kottke.org/12/05/the-isle-of-man ... -the-world