Weight distribution

[Scooby South]

Originally Posted by SubieNate

Is that with or without a driver? It's puzzling to me that almost every corner balance sheet or readout I've seen has the car at around 42F:58R. Seems pretty far off from the advertised balance...

No... thats with a half a tank of gas.. and my stock muffler ... without the muffler.. and less gas.. I was down to to 2578... and I think your reversed on the weight distribution...

[SubieNate]

@Scooby South-fixed. My bad.

So how far does it shift back with a 200 lb person in the car? Is most of that over the rear wheels?

[DarkSunrise]

Originally Posted by SubieNate

@Scooby South-fixed. My bad.

So how far does it shift back with a 200 lb person in the car? Is most of that over the rear wheels?

Toyota/Subaru claims the weight distribution of a stock 86 is as follows:

- With 2 people, 53:47.
- With 1 person, 54:46.
- Empty, 55:45.

That is F:R distribution.

[SubieNate]

Good to know.

With a full tank how close are we to 55:45 empty?

[SubieNate]

Okay, I've been thinking about this a bit, and I've come across what I think is an interesting discussion/question.

What does the weight distribution mean for the car when it's driven in a "ham fisted" manner. In essence, what happens when the limits are pushed in a non smart way.

We know that the 911 is known for it's particular steering feel due to the light front. We also know that it has classically been a definite "Point and squirt" car, where you must do your braking in a straight line. This is because with so much weight over the rear, if you transfer too much of the weight forward while trying to turn sharply, the car will snap oversteer and eat your children (figuratively of course). That polar moment of inertial that helps the car rotate so well can bite you. The front has very little weight, so it doesn't take a lot to displace it, but the rear can't follow so you go ass end first.

Now, we also see that very neutrally setup FWD cars that are front heavy do the same thing. If you transfer too much weight forward too suddenly, the rears have an extreme lack of grip because there is no weight on them. The fronts bite and the rear swings around.

Take those to things and apply what we know about handling dynamics to our car. With RWD and a slight front bias, the car should be very stable under turn in and have a lot of initial bite, but what does the car want to do after that? What determines whether we overload the fronts and understeer or underload the rears and swing the tail out?

Anyway. Just thinking out loud here. I know there's a lot more than just weight distribution going on.

Cheers
Nathan

[Captain Snooze]

Thread highjack (but relevant to weight distribution)
When 911s were mentioned in this thread I immediately thought of the Deltawing ; I think this clip is ultra fantastically mind boggling interesting.

[ame="https://www.youtube.com/watch?v=c_INdbXMqsw"]Track Test: Nissan DeltaWing Driven At Road Atlanta -- CHRIS HARRIS ON CARS - YouTube[/ame]

[Huehuecoyotl]

ok, so I'm gonna run out to the garage, hacksaw off my front control arms, and re-weld my mounts inward, and I'll also just move my motor to the back, and go tear up a few mountain bikes we own to make my car better

be back in a minute

that was a phenomenal video, thanks you so much for posting that
mind boggling innovation

is that the future of sports cars?

[Hancha Group]

As weird as the Delta Wing concept is, it is fantastic. It's mind-boggling how that thing can steer through a corner without tipping over. They built it around a target fuel consumption rate (10 MPG IIRC), which is why the car is made to be so aerodynamically slippery. While not all sports cars will end up looking like it, expect companies to try and find efficient solutions in design.

[CSG Mike]

The delta wing is all about yaw torque

[plucas]

Originally Posted by Captain Snooze

Thread highjack (but relevant to weight distribution)
When 911s were mentioned in this thread I immediately thought of the Deltawing ; I think this clip is ultra fantastically mind boggling interesting.

***video***

Side track

It was cool listening to Ben Blowlby give a presentation on the DeltaWing at IMIS a few years ago. It is a good example of thinking outside of the box and producing a car that WORKS that everybody said wouldn't work. Theoretically it worked out on paper, but many thought because of the looks, it wouldn't work at all. He proved a lot of people wrong that is for sure. He started talking about it from basic concept of a bicycle model and going from there. Very interesting indeed, but I wish I remembered more. This was around 2-3 years ago.

That said, the car is still ugly

Back on track...

[Simmons]

Originally Posted by Scooby South

No... thats with a half a tank of gas.. and my stock muffler ... without the muffler.. and less gas.. I was down to to 2578... and I think your reversed on the weight distribution...

You found out that you can't run without the muffler right?

Simmons

[feldy]

Originally Posted by Simmons

You found out that you can't run without the muffler right?

Simmons

Just under his current setup... I think Bill said he should be able to get rid of the muffler when the final nameless header comes in ect. Bill sorry if that is not correct? Just trying to remember what you said after dixie.

[icemang17]

okay I can't speak to the math mentioned....by I do know a thing or two about setting up a front engine rear drive race car......

Our cars are a bit nose heavy in stock form.......a race version would probably by similar, given the loss of interior but weight gain of a cage.....most RWD front engine cars loose most of their weight in the middle-rear.....

When it comes to adding WEIGHT for ballast......NEVER-EVER-EVER do it.....weight is the enemy....never your friend...less is always better....sure for theoretical ideal handling for a front engine-RWD setup you want around 55% rear bias....nearly impossible for anything besides a Viper or something with a front "mid" engine where the engine is at least 6-12" behind the front axle line.....

assuming our 54-55% front bias with driver there still are plenty of alignment options to make the handle to a drivers liking......add in suspension adjustments and the sky is the limit

The truth about performance "driving" on track is the DRIVER...................the car doesn't count for much until the driver is VERY experienced.......99% of the members of this forum are far better off spending their $$$$ on TRACK TIME with instruction vs buying this or that mod......

These cars were design for road courses.... not drag racing..... road racing favors the skill of the driver by a HUGE margin..... I can not tell you how many times I have passed "fast" cars on track with 600+ hp by out driving them.....even in my old lemons racer..... while I do know how to drive on track, I am far from a pro level racer.....I estimate that a true pro like Randy Pobst is around 4 seconds per lap faster than me.....

Bottom line and i will step off the soapbox....don't become a "checkbook racer" that I see on track all the time.....$pending more does not instantly make your car faster....its about small steps....1st is tires, 2nd is brakes..............97th is more power

[Scooby South]

Originally Posted by Simmons

You found out that you can't run without the muffler right?

Simmons

Originally Posted by feldy

Just under his current setup... I think Bill said he should be able to get rid of the muffler when the final nameless header comes in ect. Bill sorry if that is not correct? Just trying to remember what you said after dixie.

Correct.. the Stock muffler is on right now.. but its also within sound limits.. without it I am sure would have gotten Protested.. and Feldy is correct..
The new header/overpipe combo should be quieter than the current one..

Season gets cranked up here next week.. pretty much every weekend I will have an event somewhere..

Bill