Adding Lightness

[sdeason1]

Any ideas on how I can get more weight off the front?

I really dig the whole "rear weight bias thing".

"Simplify, then add lightness." - Colin Chapman

[Dueller]

Looks pretty light as she sits

'glass/carbon fiber hood, fenders, bumpers....lightweight battery...coil over set up or hollow sways...helium in tires?

Where ya going with the build?

[K Sykes]

Clever, is it the unobtanium front end or the helium filled fuel cell?

[DannyP]

Looks pretty light to me, it's floating in the front!

Is that a potato gun up by the ceiling?

What year is your shell?

[petevb]

Originally Posted by sdeason1

Any ideas on how I can get more weight off the front?

I really dig the whole "rear weight bias thing".

What weight and distribution are you shooting for? Tire sizes?

When you build a proper lightweight your problem is certainly going to be too little weight up front, not too much.

First, realize that if you remove weight equally front and rear you're actually increasing the rear weight bias. IE a remove 200 lbs front and rear from a 950 front/ 1450 rear car and rear weight bias moves from 60% to 62.5%.

It's also much easier to remove weight from the front- fiberglass hood, fenders, bumper, lightweight battery, less fuel, no spare, 935 front suspension, etc. It's very tough to remove similar weight from the rear. In my experience it's tough to get good turn-in, etc with more than roughly 62% weight on the rear.

My suggestion would be to pull weight where you find it but with a focus on the rear; you'll still find the distribution will move rearwards. After that if you want more rear weight bias relocate the battery to behind the seats- this alone will move the weight distribution by ~1%. Unless you have very fat rear tires, however, I'll bet you it'll handle worse...

[Dueller]

Originally Posted by petevb

What weight and distribution are you shooting for? Tire sizes?

When you build a proper lightweight your problem is certainly going to be too little weight up front, not too much.

First, realize that if you remove weight equally front and rear you're actually increasing the rear weight bias. IE a remove 200 lbs front and rear from a 950 front/ 1450 rear car and rear weight bias moves from 60% to 62.5%.

It's also much easier to remove weight from the front- fiberglass hood, fenders, bumper, lightweight battery, less fuel, no spare, 935 front suspension, etc. It's very tough to remove similar weight from the rear. In my experience it's tough to get good turn-in, etc with more than roughly 62% weight on the rear.

My suggestion would be to pull weight where you find it but with a focus on the rear; you'll still find the distribution will move rearwards. After that if you want more rear weight bias relocate the battery to behind the seats- this alone will move the weight distribution by ~1%. Unless you have very fat rear tires, however, I'll bet you it'll handle worse...

Pete...you've obviously given this some thought. How does weight distribution affect your tbar/sway bar decisions when you start jacking around balance?

[jsveb]

subscribed

[snbush67]

You should probably get that car out of there before it falls on a stripper. Cool pole.

[petevb]

Originally Posted by Dueller

Pete...you've obviously given this some thought. How does weight distribution affect your tbar decisions when you start jacking around balance?

That's question I don't think I can answer. While I've got some spring-rate tuning experience on a number of early 911s with different weight distributions, I've never done an apples to apples test where I dialed the car in then re-tuned the suspension for a different weight distribution.

My suspicion is that the bars probably wouldn't change much with weight distribution, if at all. I'd rank intended usage, tire type, power, overall weight and other suspension components all as more important variables than weight distribution with regards to T-bar size. But as I say I'm at the limit of my experience here...

[wax105]

LMAO ! snbush67

sdeason1 nice photoshop skillz...

Did anyone notice the missing jack stand?!?

[Dueller]

lol...we've been punk'd

[snbush67]

Originally Posted by wax105

LMAO ! snbush67

sdeason1 nice photoshop skillz...

Did anyone notice the missing jack stand?!?

Or the VDO clock dead center of the picture?

[wax105]

LMAO!! Just messing snbush67

[TimT]

Shot of my scales last time I set up my car.. '69 911 1846# wet

Took a bit of dialing in, but the car handles like its on rails.. no push, hint of oversteer, etc..only about 180hp now, the engines next iteration shoul be in the 210 range.. I'm sure Ill have to tweek the set up due to the increased power

[petevb]

Originally Posted by TimT

Shot of my scales last time I set up my car.. '69 911 1846# wet

Took a bit of dialing in, but the car handles like its on rails.. no push, hint of oversteer, etc..only about 180hp now, the engines next iteration shoul be in the 210 range.. I'm sure Ill have to tweek the set up due to the increased power

Nice that you were able to dial it in- without a lot of tire stagger?
It's probably getting close to 38/62 with driver? For autocross we've found we've been quicker with some ballast up front when we've gotten significantly on the far side of 62 with driver, but that's without a lot of tire stagger and with a 7:1 power to weight. It's easier to dial the same car in at the track.

Good pchop.

[sdeason1]

I was trying to make sure the chassis is straight.

The rear is weighted down with sandbags and the torsion tube is acting as a fulcrum on the two jack stands.

'67 911

Yes, it's a potato gun: YouTube - Pumpkin Death

[RWebb]

this would be a GREAT time to measure the torsional twist in the bare chassis

then add some structure & re-test...

[SCOTITUDE]

Originally Posted by TimT

Shot of my scales last time I set up my car.. '69 911 1846# wet

Took a bit of dialing in, but the car handles like its on rails.. no push, hint of oversteer, etc..only about 180hp now, the engines next iteration shoul be in the 210 range.. I'm sure Ill have to tweek the set up due to the increased power

Tim,
I finally got her stripped. Last time I weighed her she was #2875. Now if I could only get some lb's out of me!!!After all this work it kills me to put my fat ass in the car. see ya soon.