1969 Torino

[FETorino]

Originally Posted by Ron Sutton

OMG Rob,

Those wheels are really nice looking. Light too.

Yes way light for wheels that size.

Originally Posted by Ron Sutton

Rob,

I did incorrectly assume your wider tires in the rear would have narrowed the rear TW. Thanks for clarifying your car is different. You're on the right track that the wider rear TW will free/loosen up the car..

If your measurements are right ... front TW 55.25" & rear at 58" ... the math ... 1.75" more TW in the rear ... doesn't jive. That would be 2.75" more TW in the rear.

Would you please confirm the numbers, so we're talking on the same page ?

Thanks !

Welcome back Glad to hear the trip was good.

And I incorrectly stated the difference in TW was 1.75" but it is 2.75" I didn't measure these but calculated them based on the hub to hub distance and the wheel offsets.

The Panhard bar is 8" off the ground and level.

[Ron Sutton]

Originally Posted by FETorino

And I incorrectly stated the difference in TW was 1.75" but it is 2.75" I didn't measure these but calculated them based on the hub to hub distance and the wheel offsets.

The Panhard bar is 8" off the ground and level.

Hi Rob,

I don't recall working on a car with the rear trackwidth that much wider than the front. But, before I go off on one of my long explanations ... ... I had better get clear on what you want to discuss.

Do you want to talk about:
a. What the optimum set-up would be ... including tire size ... if their were no self imposed limits?
b. Tuning options to help balance handling with 21% more tire in the rear?
c. Age of the blonde in my wheel photo?
d. Something else?

[Ron in SoCal]

Originally Posted by Ron Sutton

Hi Rob,

I don't recall working on a car with the rear trackwidth that much wider than the front. But, before I go off on one of my long explanations ... ... I had better get get clear on what you want to discuss.

Do you want to talk about:
a. What the optimum set-up would be ... including tire size ... if their were no self imposed limits?
b. Tuning options to help balance handling with 21% more tire in the rear?
c. Age of the blonde in my wheel photo?
d. Something else?

Welcome back Ron! I vote 'C' plus phone number, website and personal preferences....unless you're related lol.

[Ron Sutton]

Originally Posted by Ron in SoCal

Welcome back Ron! I vote 'C' plus phone number, website and personal preferences....unless you're related lol.

You're funny Ron.

She's a slightly famous model friend we have used for promos for several years. The answers are: 25, BR-549, no website ...but she should, likes & has a Dodge 4x4 truck that she works on herself.

[Flash68]

Ron,

I think I speak for many when I say we're all glad you're back to create a diversion from the incessant trash talking.

And since we have the famous Ron in Socal and the infamous Rob in Socal, would you please do us a favor and add to your sig "Ron in Norcal"?

That is all, thanks.

[FETorino]

Originally Posted by Ron Sutton

Hi Rob,

I don't recall working on a car with the rear trackwidth that much wider than the front. But, before I go off on one of my long explanations ... ... I had better get get clear on what you want to discuss.

Do you want to talk about:
a. What the optimum set-up would be ... including tire size ... if their were no self imposed limits?
b. Tuning options to help balance handling with 21% more tire in the rear?
c. Age of the blonde in my wheel photo?
d. Something else?

No reason to avoid

a. ?

Plenty of people would want to hear that.

For sure let's go with the hard one.

b. ?

[Ron Sutton]

Originally Posted by FETorino

No reason to avoid

a. ?

Plenty of people would want to hear that.

For sure let's go with the hard one.

b. ?

Okie Dokie ...

* Rob corrected the track difference to 2.10"

a. With the 2.10" wider rear track width ... assuming it places the tires out near the fenders already ... if you were to put the same size tires on the car ... you would need to move the front tires outward. I'm assuming this would take custom fender work or flares, which is fine for this conversation, but not what you want to do. Ultimately, you would want the track width to be the same or a little wider in the front ... with same size tires.

b. With the 2.10" wider rear track width ... assuming it places the tires out near the fenders already & where you want them ... and the front tires are 285's & the rear's 345's ... we need to balance a car with 21% more tire in the rear.

We need to MAXIMIZE the front tire grip ... and reduce the rear tire grip on corner entry & Middle. Entry will be easy. Middle is always the toughest. I'll answer this in a few posts.

[FETorino]

Originally Posted by Ron Sutton

Okie Dokie ...

* Rob corrected the track difference to 2.10"

a. With the 2.0" wider rear track width ... assuming it places the tires out near the fenders already ... if you were to put the same size tires on the car ... you would need to move the front tires outward. I'm assuming this would take custom fender work or flares, which is fine for this conversation, but not what you want to do. Ultimately, you would want the track width to be the same or a little wider in the front ... with same size tires.

b. With the 2.0" wider rear track width ... assuming it places the tires out near the fenders already & where you want them ... and the front tires are 285's & the rear's 345's ... we need to balance a car with 21% more tire in the rear.

We need to MAXIMIZE the front tire grip ... and reduce the rear tire grip on corner entry & Middle. Entry will be easy. Middle is always the toughest. I'll answer this in a few posts.

Ron Sorry about the bad numbers. I think a few to many long days at work . I wanted to catch you on the PM before you used my bad number. We are basically at a 2" difference.

Maybe it's the Elephant.

[Ron Sutton]

Rob,

I tell most everyone, "we can go no faster through the corner than the front end has grip" ... and since we have 285's on the front of a big car ... we need to optimize them to their fullest potential, within the limitations you have put on the car yourself: no fender mods, 2" of front wheel lip, etc.

Here are the keys:

1. Your KPI/Caster Split should favor the caster by 0.5 to 0.75 degrees. Your C6 spindles have 9.15 degrees of KPI. Which would mean you want 9.65 to 10 degrees of static caster. That "seems like" a lot of caster, but just what the doctor ordered. GM runs this spindle at 7.7-8.3 degrees of caster in the stock Z51 & all the fast Corvette track guys run 10.0-10.5 degrees of caster.

2. You will want the A-arms installed to achieve "anti-dive." That means the LCA angles down in front & the UCA angles up in front. This will compliment the suspension set-up I'm going to recommend. And it will provide you with dynamic "caster gain" as the suspension compresses. You need about 0.5 degrees of caster gain. If you end up with more ... which would be good ... you need to reduce your static caster by the amount above 0.5 degrees.

3. How much camber gain you can end up with will also affect your roll center. Since your priorities are road course track days, Silver State high speed runs & Optima type "all around" performance events, you'll want a slightly higher front RC than you would for AutoX. I'd say 4" at ride height & 1.25"-1.5" in dive. That is easy to get by increasing the UCA angle (taller spindle or ball joint) ... which will also increase camber gain.

4. If you end up with 2.0 degrees of camber gain, I'd suggest a "starting point" of .75 degrees of static camber, for a total of 2.75 degrees of camber in dive (suspension compressed). If you end up with less camber gain ... add more static camber ... and keep the 2.75 degrees total. Other tuners may tell you need way more camber, but they're not used to working with a KPI/Caster Split favoring the caster.

5. Run .060" total toe-out. Yes ... out. Then play with the Ackerman & bump steer ... so you end up with .140"-.150" toe out ... in dive ... with the wheels turned 20 degrees.

6. You need to transfer a high amount of weight off the rear tires & onto the front tires for optimum cornering.

7. You need to achieve & maintain a low roll angle to optimize the front tire contact patches.

8. Therefore the optimum suspension set-up for your ride would be a high travel front end ... to achieve high pitch change & low roll angle ... also known as soft spring big bar.

I'll hop back on here tomorrow & outline the suspension set-up to achieve this ... along with tuning tools to balance the car at the track.

[Ron Sutton]

I corrected post #1212 after getting a PM from Rob with his spindle info.

I did not correct earlier posts to reflect his correct track width difference of 2" wider in the rear, but we'll use that number from here on out.