Need a little help figuring something out

[SSLance]

Had the local photographer look back through his pics from our last event and he found these...

Before front sway bar and rear springs (taken last fall)



After front sway bar and rear springs were installed (taken 2 weeks ago)






Before...



After...







There was 2.25" rake front to back during the last event which was a bit upsetting to the car. After my latest changes this weekend, that will change to about a 1.25" rake. That along with the much improved front geometry and improved front lower control arms should make even that much more difference in the car's cornering.

Can't wait...

[SSLance]

I've been making a little bit more progress since my last update...

Inside the frame pockets for the front coils, there were spring cups bent down at the factory to hold the top of the coil spring in place. These kept the Afco spring adjuster from sitting flat against the top of the inside of the frame. They had to go...

Before





After some trimming and bending...and some paint to prevent rust





Afco Spring adjuster welded in place.





Then the control arms were bolted into place one last time. I put a layer of grease on the bolts before installing and slowly tightened them down just until they started to impede the free movement of the control arm, then backed them off just a touch. There is zero slop in the bushing area yet the arms swings easily throughout their movement.

Pics of the LCAs in place.









Then it was time to fine tune the bump steer

I ended up with 3/16s" of spacer below the rod end on both sides and the rest of the spacers above and here are the results.



These measurements were taken 91" in front of the contact patch of the front tires. Ride height goal is 26.25" at the fender, I measured the bump steer 1 inch above ride height and 1 and 2 inches below ride height (dive).

Ron and I were on the phone back and forth throughout the adjustments...he was diagnosing my pics of measurements and advising me what to try next from 2 time zones away. I thought that was pretty cool of him.

It got late and I sent him this last picture and said I was hitting the shower. I think it's as good as we are going to get it, I know it isn't perfect but around 3/16s of an inch of bump out 91 inches in front of the tire at full dive, I'm hoping that is driveable anyway.

Next up is to get the coil springs back in the car, hook up the sway bar and bump stop, nut and bolt everything one more time, load on the trailer and take it to the alignment shop. The shop has time available tomorrow, hopefully I'll get the car buttoned up tonight and to the shop.

[Ron Sutton]

Hi Lance,

Doing the math, whatever difference you see with the laser pointing at 1/4" graph paper 91" away ... is exactly 3.5 times less when measured at the tire.

So ...
1/4" (.250") on the paper is .071" of bump steer change at the tire.
3/16" (.187") on the paper is .054" of bump steer change at the tire.
1/8" (.125") on the paper is .036" of bump steer change at the tire.
* By doing it this way ... which amplifies the differences ... it's easier to see changes & way more accurate.

While we could make many various combinations work, what I'd like to see you start with is:
Static toe-out of .060-.066" total / .030-.033" per wheel
Toe-out gain (aka "bump-out") .070"-.090" total / .035"-.045" per wheel at 2" of dive.
Dynamic toe target: .130" to .156" toe-out in dive.

You got it to here in your 2nd to last attempt.



This was very close to zero bump steer & would be considered almost perfect for most street cars. Unfortunately it was had a tick of "bump in" (slang for bump steer achieving toe-in when the suspension is in dive (compressed like it does under braking & cornering).

Since you autocross the car, we need a bit of toe-out in dive to help with initial corner turn-in response and to optimize the inside tire slip angle. We needed to add approximately .015" -.025" of shim above the tie rod end.

But since you only had a .065" shim to work with, it changed it too much & ended up like this:



This works out to about .200" on the graph paper 91" ahead ... and about .057" at the tire ... per side ... for a total "bump out" amount of .114". that could be made to work with less static toe-out, but instead I'd suggest this ...

For now, take the .065" shim back out ... get the car back to "almost zero bump steer" ... like you had in your 2nd to last attempt.

Get the front end aligned & geometry set & go run it.
Before you go to the track, by yourself some 5/8" ID shims in thicknesses of .010" to .015". At the track, add .010" bump shim above the rod end after your baseline runs. See how you like it. Keep adding shim as long as it improves turning ability. Stop & back up one shim if you go too far.

Here's why to do this way. No one can tell you exactly how much dynamic toe-out you need to achieve the optimum slip angle for your car & tires, unless they have tested the exact same set-up. Testing is the only way to know. The cool part is all you need at the track is a pad to lay on, a 5/8 ratchet & the shims.

[Ron Sutton]

Hi Lance,

My suggested starting point for your "static" front end geometry settings is:
Camber: -1.3°
Caster: 8.5° ... if you can get it.
Toe-out: 1/16" total ... 1/32" per side.

[SSLance]

Couple of quick lessons to pass along to the class. First, geometry is hard...especially if you are in a hurry. Second, things very rarely go as planned. And if anyone else attempts tack these Afco spring adjusters in place in your frame pockets, make sure they will clear the shock absorber after tacked in place.


After cutting out and repositioning the pass side adjuster last night, I proceeded to compress a spring and put it in place. I knew the fender had to go up 1" so I carefully measured the adjuster flange so that it was 1" lower than the frame pocket and compressed the spring a little over an inch to give me some leeway. Once I had the spring in place and the ball joint tight, I could not get the compressor out because the top tangs of the compressor were stuck against the adjuster. Out it all came once again. One the second try, I couldn't get the bottom wedge of the compressor out because it was jammed against the LCA spring bucket. On the the third try, I realized I only had to grab the middle 3 rings of the coil spring making not only the spring easier to compress but a TON easier to get out once the spring was in place. Somewhere along the line of this I also discovered that my tie rod end separator will not reach to break apart my tall ball joints, something I have to figure out a better way to do for sure. Anyway on the third attempt I got the spring in place and the compressor out. On to the passenger side.

This went pretty easy as I now have the procedure down pat. Then I buttoned everything else up hustling because I need to get the car down and on the trailer as I have a 9 am appointment at the alignment shop. Sway bar ends, bump stops, shocks, and finally tires installed and snugged down.

Set the car down on the ground, freaking fenders are at a tad over 27"...

I knew right away what I did. And I knew damn well that 1" at the shock was good for about 2" at the fender because I had documented all of that while measuring for shock travel. It just slipped my mind while hurrying to get this done last night. Needless to say, I was PISSED... I back the car out for a quick spin around the block anyway just to see if the steering wheel was pretty straight and if it would settle any at all once compressed a few times. Right away I noticed it wasn't steering right and headed back to the garage. Further inspection revealed that my tie rod ends are now firmly up against my sway bar.

Last time I test fit this all was before the pivot hole relocation and the bump steer adjustments, both of which raised the tie rods enough to interfere with the sway bar.

At this point, the shop is trashed, I'm trashed, and I'm in no mood to fight it anymore. So I punted...

Sometime in the future when I've calmed down and am not trying to hurry anymore, I'll pull the front springs AGAIN and readjust the adjusters properly and figure out a way to extend my sway bar links...then head to an alignment shop to work on the settings Ron posted above. None of this is a death blow, but it can work on one's state of mind. I need to recharge and hit it again later. I guess this is the difference between bolt in suspension kits and custom suspension work. I fully respect what the big companies that develop these bolt in kits go through during this process now. And I still like the way I am going about this and have learned a TON while going through this school of hard knocks. These lessons are the type you don't forget.

[SSLance]

Hi Lance,

My suggested starting point for your "static" front end geometry settings is:
Camber: -1.3°
Caster: 8.5° ... if you can get it.
Toe-out: 1/16" total ... 1/32" per side.

Car is on the trailer, appointment at the alignment shop at 1 pm.

Wish me luck...

[Ron Sutton]

Cool! Text me if you have questions.

[SSLance]

Trip to alignment shop went well. We re-set the rear thrust angle and pinion angle, then moved to the front and got as much camber and caster as well could get out of the passenger side, then made the driver side match it and set the toe.

Car drives out nice, no shimmys shakes, vibrations, or pulls. Tracks great... No sign of any bumpsteer. Didn't get too aggressive as still no front sway bar end links, they are built though, just need bolted on.

Here's the new stance



Lance is happy, now off on vacation for a few days. Will post all of the specs achieved when I get back.

[SSLance]

So, here's the sheet with the new alignment specs



We were aiming for more static camber and caster, but the back upper control arm bolt on the passenger side was too short to give us the settings we wanted. Had a couple of texts back and forth with Ron while the car was on the rack trying to decide which way to go, more camber or more caster, as we had a little bit of play room with the front UCA bolt on the passenger side and we settled on this.

We then set the driver side to match the passenger side and set the results you see above.

Here are my newly extended sway bar end links (with the old standoffs next to them).



I'll get these installed in the next day or so and do a little data acquisition with my Gopro mounted under the car to help get them set in the right place where the sway bar won't contact the tie rods and yet the ends will be set as parallel to the ground as they can be.

[Ron Sutton]

Looking Good!

Don't you have an AutoX event coming up soon ?

[SSLance]

Sunday SUNDAY Sunday!!!

[SSLance]

Alrighty then...

Barney is back down on all fours, all suspension components have been firmly reattached in the appropriate positions and more importantly...are not hitting each other anymore...

Test drive in the dark last night was successful... All it needs now is a bath and an event to go to.

Lets go racing!!!!

[Ron Sutton]

Cool. Have fun racing. Give us a complete update when you get back !

[SSLance]

So I drove the car to work today, first time on an extended highway run since all of the latest changes. I must say, the car drives fantastic!!


Not even a hint of bump steer feedback, car drifts just a tad to the right in the right lane and a tad to the left if in the left lane (following the crown of the road), no heavy feel to the steering even in parking lots, no vibrations, and just a real nice tight feel to the springs and shocks. Nothing jarring, or heavy feeling at all. I don't notice any more NVH inside the car now with all of the delrin in the front than I had before with the rubber bushings. I wouldn't hesitate to get in this car and drive it across the Country now...that makes me very happy.


When it was on the alignment rack, we spent quite a bit of time dialing in the rear control arms. We squared the rear end up as good as we could get it with the LCAs and then adjusted the UCAs to set the pinion angle exactly parallel with the trans output. This completely eliminated the pinion vibration that was evident after raising the rear ride height. 1.5 degrees of pinion angle change is more than enough to create a vibration...and the pinion angle will change that much with an inch of ride height change making it mandatory IMHO to put adjustable UCAs on any G-Body with any sort of ride height change.


I didn't hit any fast curves on the way to work, it's mostly a straight shot of highway, but I did have one slow speed exit that I played a bit on. It is amazing how this car corners now. The front is absolutely stuck, I haven't found the limit of it yet. And the rear is a bit loose but with just the right amount of throttle input, it squats down and is planted as well.


Ron coached me a bit on the phone yesterday with how to drive the car with this setup. He stressed that I need to be easy on entry, early and smooth on the brakes, then equally smooth on throttle input once the car is set in the corner while trying to maintain as much speed as possible in the turn. He says it's hard to believe this, but if the rear is loose, you can actually get it to grip by applying throttle which will transfer weight to the rear and make the rear tires grip better. I plan to put all of that to the test this coming Sunday.


In the meantime, I'm just enjoying driving the car. I'm very happy that none of these changes have disturbed the road quality experience of the car and in fact have helped the driveability. I wish all of you could go along on a ride with me to check it out.

[SSLance]

Rain...


After making a bunch of changes to the car I really wanted to feel it out, but my first two runs were wet yesterday, which was treacherous at best. It dried up a bit for the third run and a bit more for the fourth, but by that time I was trying too hard to beat the WS6 and 2011 Camaro I was racing directly against and blew my runs.


I would have beat them both if not for the cone I hit after my last trip through the timing lights at the end of the course, spun it out trying to get that last little bit.


I went out first each run, the Camaro was 4 cars behind me, the WS6 2 cars behind him


2000 Pontiac Trans AM WS6 Blue 69.095 65.660 60.466 59.739 59.739
2011 Chevrolet Camaro White 70.995 66.881 60.108 59.896 59.896
1985 Chevrolet Monte Carlo SS Maroon 70.482 67.790 60.054 59.064+1 60.054




Not only that, but my camera quit talking to my phone for some reason and due to operator error, I ended up just getting stills on my last two dry runs, not any video, so I really don't have any data relating how the suspension is working either.


http://youtu.be/AbbGNxu110U


I'm gonna run my slicks again at an autocross in two weeks, so I'll have the same traction at both ends. Hopefully that along with getting my GoPro to play nice again, will let me get a better feel for how all of the changes actually work on the track.

The car desperately needs new street rubber on the rear rims...but I'm holding out to see if BFG comes out with a 275/40/17 Rival before picking any up. Can't really tell how the car is working with brand new Rivals up front and wore out Nitto 555s out back.

I think it's gonna be good though. The front is definitely hooked up, even in the rain I never slid the front tires. Back end was all over the place though, couldn't keep it straight.

[Ron Sutton]

Thanks for the updates. Sorry for the rain.

The real test will be when you have good rubber front & rear.

[SSLance]

Yeah, I really feel like I never got the chance to see what the car can do yesterday. Even as it dried up on the last two runs, the asphalt part (where the slalom was) was still treacherous. Just when you thought it was dry enough for some grip it would lose traction completely...that led to an uneasy feeling and erroring on the side of caution while at the same time trying to go as fast as you could as your chances were running out.

Not a good combination.

When I last ran the car on street tires early this season, it would push the front tires in the corners and create the havoc I was dealing with when I started this thread. Even in the rain yesterday, it never pushed the front once. The front is really hooked up and it sure seems to not be rolling near as much as it was before. When driving the car on the street, it really feels balanced front to rear. The other night I was taking 35 mph corners on the 2 lane road at 75-80 mph and it felt fantastic. The front went where I pointed it and the back would set in yaw just a bit then just stay planted. Before in those corners at that speed the fronts and the backs would be squealing for help and this time they never made a sound. I can't wait to see what the car does in dry conditions with equal rubber on the front and the back. Hopefully we get that situation at our next event in two weeks.

[Ron Sutton]

When I last ran the car on street tires early this season, it would push the front tires in the corners and create the havoc I was dealing with when I started this thread. Even in the rain yesterday, it never pushed the front once.
Awesome. That was out goal.

The front is really hooked up and it sure seems to not be rolling near as much as it was before.
Those go hand-in-hand with your new "Tweener High Travel/Low Roll Suspension."

When driving the car on the street, it really feels balanced front to rear.
Excellent. When you get equal tires front & rear on the car, it will be pretty balanced at the track too.

The other night I was taking 35 mph corners on the 2 lane road at 75-80 mph and it felt fantastic.
Nice.

The front went where I pointed it and the back would set in yaw just a bit then just stay planted.
I know it seemed like we went up on the rear spring rate a lot ... and we did. But I calculated the FLLD & RLLD numbers and knew it would help keep both left side tires planted for more total grip. Remember, on spring rate, we went a tick on the free side.

Readers: Lance had 125# rear springs. When I ran the calcs to achieve the balance we needed with the new front sway bar, the optimum spring rate came up at 207#. I asked Lance if he wanted to err on the side of tight or loose & he choose loose. So we went with 225# springs. I think this will fastest for AutoX, but it will be on the edge of "free".

Before in those corners at that speed the fronts and the backs would be squealing for help and this time they never made a sound. I can't wait to see what the car does in dry conditions with equal rubber on the front and the back. Hopefully we get that situation at our next event in two weeks.

I'm looking forward to hearing how it goes too !

[Mizzouri]

The slalom and that back sweeper were still slick on the 4th run. I had to laugh as the 3rd heat guys had full dry pavement, and their times reflected it.

I'm ready to spend all next season going head to head! Now where did I put those 315s........

[SSLance]

I'm looking forward to hearing how it goes too !

Well, yesterday's event was a whole different story with the new setup. In order to make things easier to grade, I bolted my Hoosier A6s back on the car and ran in Street Modified for this event. This gave me equal tire grip on all four corners of the car.

I also booked to run in two heats, so I worked heat 0, ran heat 1, ran heat 2, then worked the course in heat 3. When you do this, the second heat's runs don't count towards your score, but you are still timed and get to see if you can better your time as you run. I used the extra runs to more familiarize myself with the new setup and to give some ride alongs at the same time.

The course design played right into my hands...it was beautiful if you were driving a "ground pounder" type of car. 3 straights with speeds in the 60s on all three...with just enough turns in it to make it interesting.

Here was the in car video from my 7th run of the day which was also my fastest. My passenger was the Co-chair of the event and also the course designer.

http://youtu.be/jZQiX6p-ELE

Here were my times for the day:

Heat 1
#1 53.123 (hit a cone on the inside of first sweeper, was surprised how well it turned)
#2 52.438
#3 52.307
#4 50.260 (last one that was going to count, so I stepped it up)

Heat 2
#1 50.232
#2 49.820
#3 49.553
#4 50.123 (over drove the corner after the last straight, wheel hopped under braking and dirttracked the corner)

Here are the posted raw time results

http://www.kcrscca.org/results/solo/...vent11_raw.htm

Officially I finished 25th out of 100 drivers. Had my 49.553 counted I would have finished 18th.

Check out the list of cars I finished ahead of! A LOT of those cars are considered "autocross" type cars and a bunch of them were running on some sort of racing compound tire as well. This was done with my 3700 pound 1985 Sport Luxury Monte Carlo with a full interior including AC! Nothing better in my book than beating them at their own game.

Here are my tire cam videos and my best run again, it's worth watching to the end just to hear the announcer talk about my runs. They are starting to notice me more and more now.

http://youtu.be/N3ggkP3P_tE

I'll let Ron talk about the changes we've made and how they've affected the car from his perspective...I LOVE them and think it can only get better. It's unbelievable the grip this car has now, even with the problems it still has which we will continue to correct upon.