got 16 autox runs on Sat.

Posted By: mmc427ss

got 16 autox runs on Sat. - 10/04/21 06:46 AM

Boy this autox thing can tire you out. Up at 5 for a two hour trip, back home at 7. Missed my usual hour nap in the afternoon, babies and old people need naps. The very heavy fog burned off about the first cars out. Just like running this same parking lot in June I'm like 4th car out of 120 runs in my group. I just wish instead of the 1st of the three morning run groups I'd be in the last group out. You learn so much by watching other cars from the other runs groups when a corner worker. And it pays to be assigned to a difficult corner. The downside to that is you may chase a lot of killed cones.

My son and I got four runs in the AM and four in the afternoon, they are actually two different events, you pay for each, X 2. Can get a little pricey when you have two drivers. But I'm a good Dad, just don't break the car.

The course was very fast in sections, I xxxx my way around for the most part. Struggled fighting oversteer mid and exit, just like the 16 June runs we made. But can say the car setup was identical, and expected, fight the oversteer and just get some seat time.

My son of course was faster, he was banging off the rec limiter in the straighter sections, 2nd gear. I just try to close my ears.

Tires never got very warm until the last two runs in the morning, now 10:30. Fronts picked up 4 psi , rears 3. In the afternoon runs, near 80 degrees , set 33-29 and had to drop pressure every run but tires never felt real hot to the touch. Looking around i only saw one car spraying tires. Back in June all the fast cars were spraying when it was 95.

After our morning session tire pressure set and I took all the hi speed compression out of the rear shocks, left the low compression and rebound setting the same, 5 on an 18 scale. The car was a little better mid corner but still fighting oversteer, even wheel spin on some straight sections.

A hillclimb race friend of my son was there, his wife was running her C4, he's just there to spectate only. After our second runs in the afternoon he was watching us struggle with the car all day and says forget 2nd gear, drive it in 3rd only, kill the torgue. I know the 4.11s are killing the times, besides limiting 2nd gear mph, it also is just overpowering the tires. So my third run left in 2nd and after the first corner went to 3rd the entire run. Haven't seen the results of the day yet but my son think near 2 seconds quicker on that run.
Next up is Jason, he quickly realizes that there is still a ton of torque available after nearly looping it out of a fast corner, Last run of the day I blew it. Decides to downshift to 2nd in the very slow first carousal, lost track of where I was supposed to be at exit and missed, off course. Go figure, last run of the year and an off course. Jason on his last run was trying to figure out the 3rd gear thing and was fast but still slow in our eyes.

Couple positives. The car cruised on back the 75 miles to home and even listen to some Yes on the way.
His GPS says my speedo is off more than expected after the shorter new Falkens went on.
When the weather gets cold enough will pull the 4.11s and install the 3.73 back in the car. That will help the blowing the tires off a little. The engine was build for lots of low end torque, stump pulling , it hurting us now.
After the engine overheating that cut the day short in June can say all is well now. Running two drivers you are making runs a little more than ten minutes apart, not a lot of time for engine cooling after 50 seconds of hard 2nd gear. But morning and afternoon sessions the max seen on any run was 200 and most all were less temp. Even after the 4th run in the afternoon the recovery tank showed very little gain. So cooling system is back up to par. A big deal.
Saw a little PS fluid under the car. Cap area looked good , may be in the return hose. In June lost some out of the cap. Have an F-body cooler loop added years ago which helps but may not be enough with multiply runs in a short period of time.
Couple times we heard, felt, this singular "click" with power on a left hander. Riding shotgun I thought it came from under the seat. Jason in the seat he thought his foot area. So need to go over the underside if the car looking for something. My third run of the morning the rear laterally hopped in the finishing carousal mid corner, counterclockwise. The reason i took compression out of the rear shocks later. Right side would be effected by that hopping.

Lucky enough to put 34 autox runs on the car this year. Identified the problems. Know the old guy won't get better in the coming year, and will forget what he learned. I think over the Winter the car will get a little better and the kid will benefit next year.

Posted By: SSLance

Re: got 16 autox runs on Sat. - 10/04/21 04:22 PM

You will love the difference the 3.73s make. Getting the gear right is crucial in autocross, especially with big torque engines.

Sounds like you had a good day. Think about taking ALL of the compression out of the rear shocks next time... wink
Posted By: MAP

Re: got 16 autox runs on Sat. - 10/05/21 03:16 AM

Hi Bob,

The normal understanding of understeer/oversteer is either with no throttle and no brakes, or just enough throttle to overcome tire scrub and keep the car moving at constant speed.

What's your context when you say oversteer? At the rear, any longitudinal force (throttle or braking) is pushing traction closer to the edge of the tire's traction circle, which means we're pushing closer to oversteer. And, with a front-heavy car, the traction circle diameter at the rear is relatively smaller, so we're more sensitive to throttle/braking "upsetting" car balance.
Posted By: mmc427ss

Re: got 16 autox runs on Sat. - 10/05/21 05:53 AM

In the June event had all rear shock setting at minimum as you suggested. This time wanted to see what effect pulling the high speed compression out would have, car was better.

Yes the 4.11s are a killer, really hard to apply power to the rear as it's ice skating. The factory 3.73 are sitting up on the mezz in the Yukon gear box. Some where I even have the numbers for the pinion shims so reinstall isn't to difficult. But that's a Feb project.

Forgot to mention the highlight of the day for me.
A black Tesla 3, dual motor, was at the event, I got to watch it run as a corner worker. His first run resembled my first, slow. Course setup, the start is 75' up grade to a 110 degree left, slightly back down grade to the next gate 100'. Took me several runs to get the hang of that first corner. The Tesla 3 second run he came into the first corner to hot. Now i can say I've seen a 3 do nearly a 360. Have seen a 3 at UMI three different times now and never saw one loop. Highlight of the weekend.

Today first place I looked to find that "click" noise from Sat's runs was the front UCA to frame alignment bolts/nuts. Could say the back right nut wasn't loose but was able to put a hair more tightening on that nut. Factory torque spec for those nuts is 47. Was it the "click" we heard and felt, may never know.

Started at the rear of the car up on stands looking for anything loose, abnormal, found nothing. It was a good time to wash all the white dirt under there from the stone road into UMI park. It rained that Sat afternoon and the road was wet when we left near midnight, the wheel wells, tires and rockers were all just white from that 1/4 mile long wet stone road. Had to make a trip to the local car wash Sun morning just to make the car presentable for the 250 mile ride home. Today was a start to finish the chassis cleanup for a trip made two months ago.

One observation is the stock length of the new rear shocks now seems to be good. When switching from a double to the triple adj bought a shorter shock. With a tie wrap on the shock shaft to indicate full compression travel under all conditions was pleased to see almost 1" of travel left before bottoming the new shock. The old double would push the tie wrap very close to the shock's travel limit.
Also credit some of that to the much more aggressive valving of the new shock.
For my street setup all three rear shock adjustments are turned all the way down, makes the passengers a little more comfortable but is still very firm. These Viking rear triple adj shocks have their HF, high force, valving.

Then moved to the front of the engine/chassis, again a cleanup is necessary. Inspection of the welds show nothing. The LCA frame relocation welds are all good, no signs of cracks. Couple years ago changed all 8 LCA bolt locations to move the lower ball joints forward 11/16" to allow 9 1/2 degrees caster, and to not effect the track width of the front suspension. A fun project, not, but the rewards are huge. Have not found that point where the front suspension just gives up and plows. It does everything expect, point and shoot. Pretty good for a car with near 59% of its weight over the front. Best suspension mode to date.

P/S fluid puking a non-issue at this point. Level is still on cold line, when cold. Fluid splash in the pump area was very minimal. Will see if I need to just drop the level a hair next time out. The XH 800 steering box I rebuilt years ago, you couldn't find a 600 at that time. It performed flawlessly, no signs of pump issues.

Next is get the torque wrench out and go over the 16 suspensions Delrin bushing bolts, and the 12 body bushing bolts. All have been worked pretty hard over the Summer.

Always have two "cleanup in aisle 4" places to deal with. The T56 running Mobil 1 ATF for a decade always seeps a little out the front input shaft seal. Changed the seal when the new clutch went in, but, still a seeper. not a problem, just a PITA. The other seeper is in rear main seal area. An exam of the back area of the block at clutch time showed nothing. Again this engine has been on a Mobil 1 10-30 for near it whole life and I credit Mobil 1 for the leak. The leak isn't bad, just a major PITA because, it's a leak.

Tire rub. As expected got a touch of the right rear tire, back side at frame. This area has been a concern through all the different tire sizes run on this car. It's not a bad rub, just a touch when the car is leaning over. When the new wheel spacers were made I knew tire touch there was possible. But the compromise was made in spacer thickness to keep the tires off the out well lips, didn't want to roll them. Could have made the rear spacers one mm thicker and possible had a no touch, but a compromise was needed.
Up front a BIG ZERO touch, a fat 11" section width 200 tire happy on the front of a G. A victory for the 17" wheel and tire project in the Spring.

Will access the tread wear on these new tires now with 34 autox runs and maybe 500 miles. The event lot is very old blacktop on top of a hill, it very rough in places. The fronts especially show that cheese-grader wear. Will rotate tires very soon for the couple drag race passes in a couple weeks, that will close out the racing season here. The plan is to put the old 16" wheels and tires on the car until Spring and put those new tires to bed in the warmth of my house. Need them to alive and well for the next round of autrox when it gets warm again.

Just a quick note about the two tires that run on the car. Using the car for local driving and long hauls I prefer the BFG Comp Summer easily over the new Falken RT660. The Comps taller sidewall, the Comp taller height, the Comps better in wet, ride better even at 37 psi up front, and most of all the Comps better directional stability make it my street choice hands down. With only swapping wheels and tires the car is noticeably better running down the old PA roads at 55. I point it, it stay there. With the Falkens I'm always busy at the wheel as the tires wander off somewhere. The Falken tread pattern, or lack of it, I believe is the culprit.
Yes, the alignment setup on this car is part of cause for the Falken tracking ills. With 1.5 neg camber, 9 1/2 caster and 3/16" toe out the BFG Comps have no issues. Sorry to say the 16" Comps have aged out, now 6 years old, but even at that still overall a better street tire for me.

The Falkens would do better with some toe in, maybe a tad less camber, maybe a tad higher tire pressure. Gotta give them credit, they are the fun tire for sure. HUGE advantage at the autox over virtually everything else, especially on the 86.

This year got to make 34 uneventful runs on those Falkens, most ever runs in a season. The last time was three years ago that 16 runs were made for the year on the Comps. In 2017 8 runs for the year . A lot has changed on the car in the last 4 or 5 years and sorting it out with minimum runs, and so long between events, not even taking into account reaction time of an old blind guy, just makes it a slow learning curve.
As mentioned my son co-drives with me. His total seat time on track is 14 runs at give or take 50ish seconds, a lot less than 15 minutes. Since he totaled my 72 Chevelle in 1990, he had much less than an hour cruising seat time on the street with this build. I've been building driving this car for 20 years and he just flat out beats me. The only consolation is we are both not fast, yet.
Posted By: mmc427ss

Re: got 16 autox runs on Sat. - 10/08/21 05:54 AM

Just a couple notes.
Went through all of the suspensions bolts and retorqued, then moved onto the body bushing bolts. The body bushing replacement was 2013, every year they are checked for tight. #3 bushings rearward are the hardest poly available. The #1 and #2 bushings are Delrin. What I found was the #2 right side bolt and big flat washer had incurred the wrath of the A/C condensation drainage poor design. That bolt creaked when trying to torque it. Removed the bolt, washer and lower bushing half, rust on the bolt and washer. Replaced that R #2 bolt with a spare, pulled the L #2 to inspect (perfect), cleaned and repainted the bolts and washer for each side, a touch of never-sez on the threads, good for another 6 or 8 years. Pretty sure that R #2 bushing was the "click" we felt and heard at the last event.

Cleaned up the P/S fluid under the car. It came out of the pump cap, not a leak. Will address that issue before the next event in the Spring.

After a full cleaning and inspection of the chassis, grease front end, tire pressures, fill the tank to full, ride height was checked. Still exactly where it was a year ago.
However a camber check was done and right front was neg 1 1/2 as set, the left side seems to have lost camber, only has neg 1.04 degrees. Will need to look into that soon. That much difference side to side is possibly why the car tracks the way it does on these Falken tires.

Also a check of tire rub in the front well top's and well rear's, and frame and sway bar area showed zero touch with these 11" section width tires. At the back of the car as expected a light touch on the right frame, and as unexpected a light touch on the left frame at the rear. Hindsight now says I should have added another mm or two to the rear spacer thickness.

So after 34 runs this year the car came out unscathed. Even the cone kill mark on the new right front wheel didn't leave a scratch.

Next weekend is a few runs down the 1/4 mile, the true end of the season. Haven't decided whether to put the drag race setup in the car with the Falkens or just leave it setup for the street. I would like to see if the Falkon 200 wear tire can come close to the 60' times a drag radial had, which weren't that good.

happy motoring
Posted By: mmc427ss

Re: got 16 autox runs on Sat. - 10/11/21 03:52 AM

Time to put this autox post to bed for the Winter.

Just a couple notes first.
The new Falken RT660 seem to be the tire needed to make this car much better for autox. But as a street tire it wouldn't be my choice. It's shorter, stiffer, 40 sidewall telegraphs every imperfection in the road. Sat put 40 miles with the grandkids on board, low 60 degree, the tires were actually annoying. And even at that temp the tires picked up stones and slung them at the wells at just warm tire temps. And having swapped back and forth between the old BFG Comp 2 and the 660 tracking is noticeable better with the old tires. Will check camber the toe again before removing them for the cold season ahead. Need to verify toe and camber aren't the real cause of the poor directional stability. When I put the old tires on for the 600 mile trip to UMI instantly notice how much better they were tracking than the 660s. Even when I made 3 passes at the drags a month ago noticed a little wiggle at 110 mph, almost like running bias slicks with 14 psi.
The 660 will be pulled and store in a warm place soon, save them for next season. Really won't miss them on the street.

Two improvement planned. Reinstall the 3.73, pick up 10% mph in 2nd and reduce power to the tires by a like percentage. Using 3rd gear instead of 2nd also part of the plan for the 60 mph sections.
Will look into suggested much bigger front sway bar to see how it effects mid and corner exit, the big problem with the car right now.
Also should be able to find the time to pull the front suspension and revisit bumpsteer. The plan is to "adjust" the bumpsteer to cause toe out at droop and toe in at compression to gain cheater Ackermann. Despite the car is a B spindle suspension the bump after all the changes up front is actually very good. But it's deviation is opposite of what I an now looking for. Just a matter of making another centerlink with the corrections, again.

Prior to the 34 autox runs on this car this year it was 2018 when a dozen autox runs were last made. Three years between is a long time for no seat time. A lot of mods have also been done to the car, and of course I'm a little older, the past two years aged everyone more than deserved. I feel the car was much better now, just needs some more tuning.

Can say we did get the car out there and beat on it trying to wear those new tires out. That alone was an accomplishment for the year.
Posted By: SSLance

Re: got 16 autox runs on Sat. - 10/11/21 01:30 PM

Sounds like an awesome season. Good luck at the dragstrip Bob!!
Posted By: mmc427ss

Re: got 16 autox runs on Sat. - 10/12/21 10:10 PM

In case anyone is interested Tom Hamm, a professional photographer, shows up at Susquehanna autox events and takes great pictures. There are 25 pics of the 86 on course. Pages 33 and 34 are #66, me, and page 51 is #266, the boy, my soon to be 48 year old son Jason.

Posted By: AkronAero

Re: got 16 autox runs on Sat. - 10/13/21 02:00 AM

Bob - really nice pics! On my viewer you are page 27 (photos # 656-665) and Jason is Page 41 (photos # 1006-1020).
Someday we will meet up.
Great times! Gordon
Posted By: mmc427ss

Re: got 16 autox runs on Sat. - 10/13/21 04:34 AM

Was only 20 pics on a page early, now 25 pics on a page. Thanks for catching that.
Pictures and videos help get an idea of what the car is doing. Saw that when drag racing using pics and video of launch. GoPRO provided all 34 runs this year, the pics by Tom add another element.
Posted By: mmc427ss

Re: got 16 autox runs on Sat. - 10/21/21 03:10 AM

Making passes at Maple Grove Raceway last weekend didn't happen. Being the racer insensitive drag strip "The Grove" is they cancelled Fri evening test&tune and Sat morning/afternoon test &tune because of rain coming in the later Sat afternoon. Did I mention, insensitive.
Two friends want to make passes on their cars before the malls runs out of Christmas toys for the kids. Cecil County Dragway is scheduled for several test&tunes up till the end of Nov. I may join them for the 60 mile trip there just to make a couple more passes. Nothing definite.

Also Susquehanna has one more autox event on the 30th. That I haven't ruled out yet. That event is kinda a play time there. Make runs in the morning and then some type of runoff in the afternoon for fun. Not sure how it works but who knows, the car may show up there, for some fun.
Posted By: 88ssBrent

Re: got 16 autox runs on Sat. - 10/21/21 03:29 AM

Bob, hope you can get in all the runs you want, either drag, autox, or both. Not much more planned on my side just a few more cruise ins and cars and coffee then put the car up for the year.
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