Bad Day...Good Day for Porsche at Le Mans...

[Tilikum Turbo]

Well, neither the 919 or the 991 RSR fared very well in this years Le Mans, but the 919 is radically new technology(pushing a 4-Cylinder to compete with a V-6 and a V-8) which will undoubtedly alter the future of automotive technology(as will the 918), & Porsche makes a fortune selling and licensing intellectual properties to the automotive world.

911 RSR was effectively 'neutered' after Silverstone with a balance of performance 'adjustment', but that's the breaks after winning last year in it's class at Le Mans, and Daytona, and Sebring and another 1-2 in the first FIA-WEC race. Luck also is a variable no one has control of, so the spoils have to go elsewhere this year on the big race.

Just as the original 917 debut, the 919 will greatly benefit another year of development, and we may even see a 4-way battle next year as Nissan is trying to bring the GTR into the fray. All good stuff!

[Don Plumley]

Agreed!

[dave 911]

what were the major issues with the 919 cars?

[onewhippedpuppy]

I don't think many expected them to win the first time out. They were competitive and will no doubt learn from the issues they encountered this year. Next year will probably bring much higher expectations.

[sammyg2]

A V-4?

giggle.

When I first read about these cars I was saying to myself, why in the heck would anyone try making a V-4 again?
It's inherently a bad design. Lots of strange harmonics and forces that can't be completely balanced out and can only be partially dampened.
Kinda like strapping two harley motors together and see which one shakes the other apart first.
I wondered how they could keep an engine like that alive for 24 hours.

A 90 degree V8 is inherently flawed but can work well if balanced and dampened well.
A 90 degree V6 is worse.
An inline six is sooooo much better from a balance and force and vibration standpoint, and a flat 6 is better than that.

An inline 4 is OK, a flat 4 is better, a V-4 just flat out sux from a vibration dynamics standpoint.

Can it be done? Sure can. Can it work? Yep, to a certain extent. Are there better designs out out there? Hundreds of them.



(I've got level 1 and level 2 vibration analysis certifications from Emerson/CSI. Level 1 and level 2 vibration analysis certifications from Entek/Rockwell Automation/IRD. Level 1, 2, and level 3 vibration analysis certifications from the Vibration Institute).

Unfortunately I doan have no certs in photography.

[Flieger]

Originally Posted by sammyg2

A V-4?

giggle.

When I first read about these cars I was saying to myself, why in the heck would anyone try making a V-4 again?
It's inherently a bad design. Lots of strange harmonics and forces that can't be completely balanced out and can only be partially dampened.
Kinda like strapping two harley motors together and see which one shakes the other apart first.
I wondered how they could keep an engine like that alive for 24 hours.

A 90 degree V8 is inherently flawed but can work well if balanced and dampened well.
A 90 degree V6 is worse.
An inline six is sooooo much better from a balance and force and vibration standpoint, and a flat 6 is better than that.

An inline 4 is OK, a flat 4 is better, a V-4 just flat out sux from a vibration dynamics standpoint.

Can it be done? Sure can. Can it work? Yep, to a certain extent. Are there better designs out out there? Hundreds of them.



(I've got level 1 and level 2 vibration analysis certifications from Emerson/CSI. Level 1 and level 2 vibration analysis certifications from Entek/Rockwell Automation/IRD. Level 1, 2, and level 3 vibration analysis certifications from the Vibration Institute).

Unfortunately I doan have no certs in photography.

Vibrations aren't the only factor for a racing engine. But Porsche did have to change the spacing of the crank throws to reduce the vibrations that were shaking their hydraulically-interlinked suspension to pieces in their initial design.

Not the first time, the 908 had to go from flat-plane to crossplane to keep the tube frames from cracking. That meant a more complex exhaust though.

[sand_man]

Originally Posted by sammyg2

A V-4?

giggle.

When I first read about these cars I was saying to myself, why in the heck would anyone try making a V-4 again?
It's inherently a bad design. Lots of strange harmonics and forces that can't be completely balanced out and can only be partially dampened.
Kinda like strapping two harley motors together and see which one shakes the other apart first.
I wondered how they could keep an engine like that alive for 24 hours.

A 90 degree V8 is inherently flawed but can work well if balanced and dampened well.
A 90 degree V6 is worse.
An inline six is sooooo much better from a balance and force and vibration standpoint, and a flat 6 is better than that.

An inline 4 is OK, a flat 4 is better, a V-4 just flat out sux from a vibration dynamics standpoint.

Can it be done? Sure can. Can it work? Yep, to a certain extent. Are there better designs out out there? Hundreds of them.



(I've got level 1 and level 2 vibration analysis certifications from Emerson/CSI. Level 1 and level 2 vibration analysis certifications from Entek/Rockwell Automation/IRD. Level 1, 2, and level 3 vibration analysis certifications from the Vibration Institute).

Unfortunately I doan have no certs in photography.

And you stayed at a Holiday Inn Express last night. Seriously, thank you for the info. I didn't realize all of that.

[Steve Carlton]

Interesting info, Sammy. What's your opinion of I5s and a 60-degree V8 (Yamaha built for Volvo)?

[sammyg2]

LOL I member reading about some furrin car company when I was in college.
Seemed they had designed a passenger car with 4 wheel drive. Yeah I know.
But here's the really weird part:
They put an inline FIVE cylinder engine in it. No seriously. A 5 cylinder. Why? Why create problems for yourself intentionally with an odd number of cylinders?

What in the world would that crank have to look like just to hang the counterweights on it? I was sure there would be no way to internally balance it, they'd have to hang a big ole counter-weighted harmonic dampener on the end of it.

Could they not go big enough with an inline 4 cylinder? did they not have room to fit a 6 cylinder?
We're they just trying to impress the boss by designing something no one else does?
(hint if no one else does it, there's most likely a good reason they don't).

But believe it or not that car with the 4 wheel drive and the inline 5 cylinder engine turned out to be a success despite the inherent challenges and they sold a ton of em over the next decade.
EDIT: Turned out it wasn't much harder to balance than an I4, just needed to do a little more slide-rule work and calcumalations.


I wouldn't mind owning a clean low-mile version of that car today!

[sammyg2]

Originally Posted by Steve Carlton

Interesting info, Sammy. What's your opinion of I5s and a 60-degree V8 (Yamaha built for Volvo)?

i wuz typing part of that answer before you axed it.

As fer 60 degree V's, it's all about packaging. Making it smaller so it'll fit.
IOW compromize.

Is a 90 degree a better design? Yes. Can a 60 degree work? Yes. But it has inherent challenges that must be addressed to keep the engine alive and reliable for a long time.

What's the smoothest engine that comes to mind? Ferrari flat 12. Naturally balanced, almost no additional metal required.
The Porsche 917 flat 12 was a compromize and acted more like a flat V8 than a true opposed boxer so it weren't as good as ferrari's version.

V-12s are also pretty darned smooth too without a whole bunch of extra rotational mass.
(extra rotational mass = less HP).

The porsche flat 6 is smoooooth but really long due to the independant throws and extra mains. But it has a minimal amount of counterweight which is always gud.

I also like the straight 6 like in the datsun Z cars and the beemers. They seem to run OK but take up more room and need a long-snout on the car.

The more counterweight you have to add, the more dampening, the more rotational mass needed to counter-act forces due to design configuration, the worse the design is and the more that can GO WRONG. IMHO of course.




Did I mention I have a certificate from Schenck Trebel for "Balancing theory and Applications" and another from Emerson/CSI for "Field balancing applications using the CSI 2130"?

I also have a Schenck Trebel balancing machine in my shop capable of hitting a tolerance of W2/N in many cases which is tighter than required on nuke subs. We can hit W4/N all the time.
Darn thing cost $60k.

[tadink]

Originally Posted by sammyg2

A V-4?

giggle.

When I first read about these cars I was saying to myself, why in the heck would anyone try making a V-4 again?
It's inherently a bad design. Lots of strange harmonics and forces that can't be completely balanced out and can only be partially dampened.
Kinda like strapping two harley motors together and see which one shakes the other apart first.
I wondered how they could keep an engine like that alive for 24 hours.

A 90 degree V8 is inherently flawed but can work well if balanced and dampened well.
A 90 degree V6 is worse.
An inline six is sooooo much better from a balance and force and vibration standpoint, and a flat 6 is better than that.

An inline 4 is OK, a flat 4 is better, a V-4 just flat out sux from a vibration dynamics standpoint.

Can it be done? Sure can. Can it work? Yep, to a certain extent. Are there better designs out out there? Hundreds of them.



(I've got level 1 and level 2 vibration analysis certifications from Emerson/CSI. Level 1 and level 2 vibration analysis certifications from Entek/Rockwell Automation/IRD. Level 1, 2, and level 3 vibration analysis certifications from the Vibration Institute).

Unfortunately I doan have no certs in photography.

uh, and so was the camera *vibrating* when you took this picture???

[sammyg2]

Originally Posted by tadink

uh, and so was the camera *vibrating* when you took this picture???

Just got one of them fancy smart phones a couple weeks ago, first time trying to take a pic with it.
Darn thing has a hair trigger, clicked too easy when I wasn't holding still yet.

It looked fine on the phone but when I sent it to 'puter it was fuzzy.

I said what the heck, close enough.
You can call me Byron