bags142

I am finishing installing my poly bushings. I am starting to think about an alignment. From looking at PFADT's posts and alignment suggestions, it seems I should go with the performance street since I use "street tires" during hpde's.

Looking at the track car with poly bushings and race tires they run less caster. From reading, they recommend less caster due to less flex in the poly than in the stock rubber bushings.

So I am in the middle. I have poly bushings with street tires. I also have little to no driving talent FWIW. So, I was thinking about running

Front
Camber -1.2
Caster 6.5
Toe 0.17

Rear
Camber -0.8
Toe 0.33


I am not overly concerned with tire wear, but my car does see about 10k miles a year and 4-5 hpde's a year.

Thanks and I did try to search to get my answer before posting, so if this has been covered I missed it.. sorry

froggy47

I run -3.0 and -1.6 WITH poly but very few street miles, mainly to/from events.

But that's with a6's.

Pfadt Racing

Hey Bags142. Given that the car doesn't see a massive amount of track time we would recommend setting the car up with the Aggressive side of the Track Use with Street Tires setting. Take some tire temps during your first HPDE and see where the heat is really being generated in the street tires, if it's still significantly on the outside edges of the tires dial in a little more camber for a track optimized setup.

As you move to stiffer bushing materials like poly you lose some Dynamic negative camber gain that's built into the control arm system, so you need to dial it back in with your static alignment. You don't want massive amounts of negative camber to start with, but you may end up needing a little more negative camber than normally necessary with a street setup because of the change to poly. Start out with the settings you've got posted and take a little bit of data at the track to help dial the alignment in.

drivinhard

toe will eat tires more than camber, you can actually run a lot of camber so long as the toe isn't real aggressive

froggy47

Just when I thought I had started figuring out alignment.

Dynamic neg. camber gain is MORE with rubber than poly?

I "thought" you went to poly so that you KEPT more of the static neg. camber that was set?

And if you choose to, use LESS neg. camber settings. Or (if the car/driver likes it) use as much of a setting as you might need with rubber.

I'm confused.

bags142

Thanks


Ah.. ok Thanks! Guess I should have just called y'all to start.

On tire temps, all I have is a harbor freight laser pyrometer, I am guessing that won't work in this instance?


Thanks!

travisnd

When I was doing dual duty in my old Z06 I always tried to be around the following:

Front:
Camber: -1.2
Caster: +6.0 or above
Toe: 0

Rear:
Camber: -0.9
Toe: 1/16th per side toe-in; 1/8th sum toe

As Mark mentioned above toe will destroy a tire on the street. Driving in a straight line you're effectively dragging the tire over the pavement.

You run a little toe-in out back because as the suspension loads off of a turn the tires will actually square up and give you better traction. This happens less with polys than it does with rubber.

RX-Ben

I go big on camber (2.5 last year, hoping for 3 this year), straight on toe in the front, 1/8" total in the rear. My tow vehicle is my track vehicle so it gets a ton of miles. Good street tires (Direzzas) lasted about 12k miles.

froggy47

You mean toe in the back, right?

Pfadt Racing

When you move to poly or a spherical you will end up with less dynamic gain, so you need to make up for it by dialing in a little more negative camber on your static settings. Part of the reason we recommend more aggressive negative camber settings with our poly kits is to account for the this, the other part is typically folks on poly bushings are running tires that are more suited to more aggressive negative camber settings.

It's probably close enough for government work. They're a little easier to use than the probe style and there are always folks at the track using similar equipment. If you're running a full race effort a fancy gauge may be nice, but for a track day driver looking to get a little usable data it's probably just fine.

bags142

Thanks!

bags142

Ahh.. and yeah I am just having fun and trying to understand and get a little better

froggy47

This dynamic gain with stock/rubber bushings, is because of the geometry of the suspension components & is intentional on the part of the manufacturer?

How many degrees are we taliking?

Olitho

This just does not sound right to me even with the explanation....

I can sure see how toe deflection is less with poly or Delrin, but I would expect the deflection on positive camber to be less, too, unless you are telling me the leverage forces on the A-arms with rubber increases the negative camber vs. reducing it as I presumed.

RX-Ben

Pfadt has it right on their recommended settings, but reversed above (I believe).
Stiffer bushings = less dynamic gain in camber (i.e., towards evil positive camber), so less negative camber is initially needed for the same dynamic settings.

travisnd

Yeah I've always heard you don't have to run as much static camber with polys because the A-arms won't move as much.

Olitho

10-4. That was my impression, too. I guess I interpreted the Pfadt posting incorrectly.

RX-Ben

I will say that despite delrin, I would've needed F1-level negative camber to neutralize the dynamic camber gain from body roll when cornering on base model suspension.

froggy47

Head starts to throb

bags142

Thanks!

I will be buying a trailer later this year too! Do you run the direzzas on track or just the street? I know the bmw and miata guys love them.











This makes baby jesus' head heurt..I am going back to looking at **** on the internet as god intended it!

jk.. I am trying to keep up...