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#1064341 - 12/02/19 07:02 PM Re: Rear spring options for handling [Re: mmc427ss]  
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mmc427ss Online content
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Had a long conversation with Viking today about shocks. Being my shocks are several years old now and costs to shorten is close to cost of new it would be better to just sell the set I have and buy new shorter shocks. Not a big deal just opens the choices for other options. Mike, tech at Viking, said they're soon to release their new shocks, a triple adjustable in both smooth body and coilover. It will have rebound and low and high compression adjustments. Hmmm. price will be higher than the double adj, doesn't use a remote reservoir, and all three adjustment are on the bottom of the shock.
So for now the shocks are on hold until after the 1st of the year when i will call them back for an update.

Viking had their test bed Camaro at UMI's King of the Mountain with the triple on it. I should have spent time talking to Mike and Chris when I was at the event instead of just looking at the car. But didn't think I was in the market for rear spring/shock project then. Oh well.

Lousy weather, bad right knee, not much time for beating on the car to test springs right now.
Bob

#1064342 - 12/02/19 07:09 PM Re: Rear spring options for handling [Re: mmc427ss]  
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My favorite part of that camaro was the front sway bar location.


86 SS
400SBC, 4l80e, MSD Atomic injection/trans controller, Tilt glass clip, all tubular arms, corvette brakes, 9" rear
In progress
#1064344 - 12/02/19 11:17 PM Re: Rear spring options for handling [Re: mmc427ss]  
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Is that the one with the mufflers in the trunk?


Lance
1985 Monte Carlo SS Street Car
#1064345 - 12/03/19 12:34 AM Re: Rear spring options for handling [Re: mmc427ss]  
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This is the car they had at KOM. Didn't see the trunk or hood open.
Mufflers in the trunk?

https://www.umiperformance.com/kotm/wp-content/uploads/superforms/2019/02/661271064/ousci1.jpg
Bob

#1064346 - 12/03/19 12:42 AM Re: Rear spring options for handling [Re: mmc427ss]  
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Yup, that's it... And yes, exhaust is routed thru the trunk...


Lance
1985 Monte Carlo SS Street Car
#1064357 - 12/04/19 07:11 AM Re: Rear spring options for handling [Re: mmc427ss]  
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After hobbling around on a bum knee the past five day got it fixed today, turned out just needles, good to go. So if i can get the car warmed up, hopefully a warm 40 with some sun for a change, then it's a short road trip and some rear shock adjusting along the way. Why can't the front shock adjusters be that easy to get to? The UMI springs are in the car now, go.

First order of business is hard braking, need to know what those rear brakes are going to do. Changing rear spring rate should effect antidive. More spring rate, such as going from a 100 to a 200 rear spring, should raise the ride height quicker on hard braking which transfers weight to the front, and takes weight off the back tire.

The old Global spring removed were 130 linear rate, antidive was good, the car stopped very good. Both "dual rate" springs I'm testing (100/200 and 150/250) are a 100 low rate on my scale. When those springs transfer from a high rate, say 200 at ride height, then reduce rate while going into droop, when does that lower rate kick in, and did it effect antidive noticeable. One of the reasons racers don't like progressive springs, linear more predictable in braking and handling so they say. Makes you wonder why so many "handling" springs are progressive.

There are some pretty good "whoops" close by. Compression/rebound setting on the rear shocks 8/8, about mid point , will stop afterwards and look at the tie wraps on the shock shafts. At that compression setting it shouldn't bottom the shock out. Will then crank the compression down, reset tie wraps and see if ride improves. Past road trips the butt dyno noticed the high rate of both the 200 and 250 springs. Hoping to see shock setting make a difference. I already know that the tie wrap will be pushed to the top of the shaft after a short easier ride over the whoops again. A shorter shock will solve a couple issues, bottoming out of the shock and also reducing the space to install the spring. No chance of the UMI 13" spring falling out now, but downside is shock would need to be removed to drop rear enough to pop spring in. Something I was hoping to avoid. On the bright side I think the Ricetec 12" spring would pop in with the shorter shock connected.

Ride height for both the 12" and 13" springs was within reason, but both may get a shim or two to suit my fancy later. Already have used the 1" shim for the 12" spring and the 1/2" or so F insulator with the 13" spring. Both are very easily shimmed in the end.

Hoping to put enough time on the car tomorrow for it to get a full tank of gas again.
Bob

#1064366 - 12/05/19 06:38 AM Re: Rear spring options for handling [Re: mmc427ss]  
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Despite a snow flurry before I awoke this morning the roads were dry enough for an hour of driving by noon. Only 40 and no Sun it took several miles to get the car's creaks quieted down, Cold tires with 37 lbs, Delrin everywhere, stiffly sprung, like me we like it 70 degrees out.
Made three trip around a several mile circuit with three shock settings, 8-8, 4-4, 2-2.

Antidive was good at 8-8, on pair with old springs. No rear lock up at all, felt good even though the roads still had some moisture in them. Having shock rebound at 8 was helping to keep the rear planted. As I lower shock setting antidive gets worse and at 2-2 I was paying attention to the rear tires to avoid sliding.
Antidive needs high rebound.

Wheel hop, had none on any shock setting. But traction was not good anywhere I lit them up, cold tires and cold damp roads don't mix well.

Ride quality gets noticeable better as the shock setting decreased, as it should. Ride was good even at the 8-8 but at 2-2 I drove the car about 10 miles and thought that's not bad. Stopped at the Sunoco and topped the car off, coffee, enjoy the ride on that 2-2.

Made three passes over the same whoops at about 70, airborne would be able 85 I'd guess. good test of shock compression travel. Good at 8-8, 4-4 could live with, 2-2 the tie wraps were at the top. So a shorter shock is needed.

Cornering was limited to a 1/2 mile stretch with two low speed tight 90s, a sweeper and another blind left 90. Noticeable the car was better with the 8-8 setting. Didn't seem to get upset in rear getting into mid corner as it did with the old springs. Is this a result of more spring rate, a progressive spring rate? With the old spring typically settings would be 6 comp 7 rebound. As the shock setting were lowered that upset came back. On the 2-2 setting the car became a handful. Almost lost in one corner on the trip back to the shop. You couldn't tell the road was salted that morning, or maybe I was going to fast to see that. Just got my attention real quick. Back to the shop, enough is enough.

Got back to the shop and did ride height, it needs to go up 1/4". Made a trip to a friends business, big boy trucks with heavy duty mud flaps. Found a 1/4" thick cutoff, same stuff they make muffler hangers rubber out of. My 6" hole saw is very dull and it took awhile to cut, along with smoke, two 1/4 shims. Removed the UMI spring, four stainless flat heads attach the shim to the back of the F -body top insulator. This is a permanent install. Put the springs back in, up 1/4" to 26 7/8", bingo.

Was going to throw the Ridetec spring in but instead decided to drive the UMI for a few days and throw some different shock setting at them. With another holiday quickly approaching time is getting used up. I still need to find a 5' live tree for less than 60 buck.

happy motoring
Bob

#1064368 - 12/05/19 03:22 PM Re: Rear spring options for handling [Re: mmc427ss]  
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Nice data collecting Bob, only to really test things for sure. What you will find later is that rebound is great for anti-dive...until it isn't. At some point you'll cross the line between too much rebound and too abrupt and harsh brake threshold and you'll lift those rear tires right off the ground. This will happen especially when there is steering input initiated as well (like on corner turn in). This is when you'll learn that backing that rear rebound back out will help settle the rear of the car on corner entry.

Keep up the good work.


Lance
1985 Monte Carlo SS Street Car
#1064374 - 12/06/19 07:06 AM Re: Rear spring options for handling [Re: mmc427ss]  
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Thanks for the input Lance. Sorting all this out between springs and shocks gets time consuming.

Took the car out for a short trip this afternoon on the same circuit I made three trips around yesterday, With the additional 1/4" added to the insulator each side the ride height now at 26 7/8". The trip was needed to insure the springs were settle in. One of the nice things about the UMI springs is they seat on the pigtail mount on the rear nicely, good contact. Another is they are a very good free length and shouldn't drop out at full drop. And a shorter shock will guarantee that.The shocks settings at 6-6 was just another setting to see what they felt like. Ride OK, whoops test at 70 mph still had 1/2 " travel left in the shocks, mid corner entry was good on one 90, other it got loose but didn't have that settled/unsettled rear roll, just got loose, antidive rear tires got loose but think that was surface traction and cold tires mostly.
Back at the shop ride height 26 7/8. GOOD. Current F-body insulator with the 1/4" shim works.

Tonight pulled the UMI to install the Ridetec but first did all spring measurements on the three sets of spring, Wire diameter, wire length, number of active coils for low and high rate, and installed free length.
But first after handling the three sets of spring something is very noticeable. The Global set of springs and the UMI F springs both weight 9 1/2 lb a pair. The Ridetec weigh in at 19 lbs for a pair. WOW. The linear Global have a .531" wire at 89" long, four active coils . The UMI 100/200 wire is .482" at 115", with 3 low and 3 high rate coils. The Ridetec 150/250 wire is .560' at 153", 5 low and 3 high rate coils. That's why they are so heavy.

Spring free length with appropriate insulators. The old Global springs with a stock lower and stock upper pigtail insulators are 13 3/8". The UMI springs with a stock lower insulator, a stock F-body top insulator with a 1/4" shim added are 13 7/8". The ridetec with stock lower, stock pigtail upper insulators and a 1" temporary plywood shim measured 13 3/8". After gathering that info installed the Ridetec springs in the car.

Because the Ridetec free length without insulators is short, 12" compared to the UMI 13" and the Global at 12 7/8" the Ridetec springs are loose and could drop out. I had to jack the rear up until they hit their upper seat and insure they were in position. Dropped the car on the ground and wow, 27" ride height, hmm. Will drive the car in the next day or so and make sure they are seated and see if still 27", but that's a good number. But using a 1" spacer to do that.

Initial low rate testing on a scale I did said both the UMI and Ridetec were 100 lb for the first two inches. If the UMI is 13/7/8 ", and the Ridetec is 1/2" shorter at 13 3/8" and now the ride height went up to 27" from 26 7/8" that tells me the Ridetec high rate is higher than the UMI. . Wire diameter and length would suggest that and last week's Ridetec test drive compared to the UMI this week the butt dyno said yes ride quality is different.

Will try to get out again tomorrow on the ridetec to get a feel for them. I know the 70 mph whoops test won't happen, don't trust the spring being that loose. Changing to a 3/4" shorter shock may fix that, but not until then. Can do the rest of the tests though while playing with shock setting. It will be interesting to see if the Ridetec feel any different into the two 90 I use. That was the whole intent of starting this project, transition into mid corner.

Soon the Global spring will be reinstalled. I found another source for a spring checker, one of my drag racing friends has a guy who tunes drag car's chassis and can do long springs. Will take a Ridetec and UMI spring and log rate as the spring compresses to see how and when they transition rates. I'm guessing there will be big differences between them. The hefty 19 lbs, more low rate coils, short 12" and ride height went up and 1/8" on the Ridetec indicates that. Those specs got from a rater are important.

Soon may be able to put this to bed for awhile. The goal was to find a spring/shock combo to get into mid corner. Closer now than a month ago.
Bob

#1064375 - 12/06/19 03:17 PM Re: Rear spring options for handling [Re: mmc427ss]  
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Lots of info, I'll need to go back and re-read some of it, but nice to maybe help out others as well with all of this R&R.

I replaced the rear Eibach's in my SS this summer, if I still had them I could of sent them to you to test out if you were interested but sold them to another member on here. Was happy with Eibach's on both of my Monte's for all these years. Also had a complete new set of Eibachs (front and rear) that I planned to use in my wagon but realized they wouldn't work, tested the rears and the wagon dropped 3.5", knew it wouldn't be the 1" for a coupe/sedan g-body but wow.

I went with the UMI 2" for the SS in rear since my front is lower than when I just had the Eibach's on all four corners and b-body spindles. My ride height after the 2" was right about 26" in the rear I believe. I didn't get spring specs but have been happy with the ride, also used UMI shock relocation brackets($) to lower the shock location, the disc brake conversion caused the shock length to get shorter and the even-more-lowered springs made the shock travel an issue. Problem solved.

And yes, coilovers would be the easy way out laugh . I'm too far in front and rear with new pricey parts to go back and once dialed in, will be just fine for me as I don't have a desire or real need to adjust things, rather just hop in and go. But for the initial ride height adjustments to dial it in, would of been much easier. Having fun with the front end right now, just replaced the Eibach's and the 25" ground to fender lip height with Moog 5660's, bumped it up over 1.5", wanted 1" but not sure about the last .5-1", will see how things settle once driving it then trim if needed. Level height is the goal, 26.5" all around would be perfect I think. I scraped/cracked the passenger inner wheelwell from the lack of height, also other negative aspects of being so low (bumpsteer, shock travel, ride quality, etc). Might have to check which isolators I have in the rear, or if I want to ever so slightly bump the height up in back, might be something that factors in.

Last edited by PB86SS/87LS; 12/06/19 03:29 PM.

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#1064443 - 12/14/19 04:39 AM Re: Rear spring options for handling [Re: mmc427ss]  
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Paul thanks for the input. I know with all the suspension changes you made to the front it takes time to dial in the ride height.

For most guys ride height is about appearance, the look, we all have an opinion on "the look". For me it's about being able to navigate the back roads here without worrying about throwing sparks. My ride height parameters are for that purpose and to allows as much articulation in the suspension, particularly in the front, as possible. The amount of front suspension travel from ride height to full compression on these cars is not much, less than two inches on most cars, lowering the car can reduce that distance, sometimes a lot. Bump stops and wheelwells suffer. Of course tires, wheels, springs, shocks, spindles and a host of variable come into play. The front suspension on my 86 is unique to the car so front ride height is dialed in to that. But with a 1" wider track width, 9 1/2 caster, -1 1/4 camber, a 10.3 section width tire, zero tire rub. Moving the lower ball joint forward gets most of the credit for that. Currently at  26 1/2" front due to the 26" tall tires I run. Going to a more common 25.6" tall tire would drop that front close to 26 1/4 which I could live with.

My intent with this post was to explore the possible rear spring options to hopefully cure the loose transition getting into mid corner. You could feel the loaded/unloaded/loaded rear tires as the weight transferred from inside to outside. And being springs are cheap it's the first place to experiment with. There are no less than 20 springs (G and F-body) for the rear of the car to look at without even taking into account coilover springs/shocks.

Part of the criteria for a rear spring was it had to be able to not get to loose and fall out/off of it's seats in full droop. Seat to seat distance, no insulators, hanging on the shocks with no springs now is roughly 14", about average for an SS. Of course shock extended length dictates full droop. Springs with free length less than 14" can be a problem keeping them seated. The Ridetec at 12", is a candidate for falling out. The UMI spring at 13" with insulators and a 1/4" shim to get the rear ride height correct is 13 7/8", almost a perfect fit currently. Pretty sure it will become my new street spring setup.

Another was the final rear ride height had to be easily dialed in using shims rather than weight jackers and the two springs tested can now easily be swapped and have correct height. Just don't trust the short Ridetec without preventing it from falling out. It may become the autox spring so will fix that falling out problem.

Haven't had any time to drive the car the past week. The weather, holidays and front brakes on the 02 SS Sat so I could do a 600 mile round trip to a funeral in Pittsburgh Mon-Tues. I hate driving 70+ on the turnpike for hours in the pouring rain, to many trucks slowly passing each other. And old people don't even see good in the nice weather.

There's a coolant leak at the 02 SS's 3.8L EGR/plastic plenum area, most likely heat cracked, a common problem. The plastic cracks from the EGR heat. Replaced the plenum when I did intake gaskets, also big problem on the earlier 3.8. It was a Dorman plenum, maybe why it needs to be replaced again after only 7 years. Now a Sun project, new plenum and gaskets sitting at the shop.For the Pittsburgh trip the overflow tank got an extra qt, a gallon of water in the trunk, crossed my fingers knowing about that leak before I left on the trip, it only used about 4 oz of coolant. The 86 will sit again so a plenum can be replaced.

Next up on the rear spring project is putting them on a spring rater to check rate from free height to about 8' compressed length. That should tell me at what length the two different springs transfer from low to high rate and what their true low and high rates are. Already knowing what each spring's compressed length is at ride height will then be able to compress each spring to that height and see the load pressure (spring rate) changing as you go up and down in length. That should indicate the rate transition at what compressed length. Also have a good guess at spring load at ride height. With 780 lb rear corner scaled weight, all be it dated now, thinking in the area of 600 lb sprung weight is what the spring sees. The spring rater will also tell me what that load rate is at ride height and verify the 600 lb. That number makes it easier to chose a high rate linear spring, maybe 175-250 range if I go that route later as a trial. Those spring from even the best manufactures aren't expensive, easy to trim in a tangential top used in the F-body.  

Today talked with my new contact for a rate checker, Shane at Competition Suspension Solutions, drag race cars predominantly. Shane is another one of those shock gurus, built shocks for Penske previously and has an Intercomp rate checker with an invite to use it. Cool. Hopefully this is the one he has.

https://www.intercompracing.com/2000-lb-digital-coil-spring-tester-p-120.html 

May even drive the 86, with the old rear springs installed, just to use it the 3/4 hr drive to his shop. Going to try and do that by next weekend. I've got a trunk lid and spoiler on the list for some paint touch up yet this winter, got to try and put this rear spring project to bed till Spring, almost done.
Bob

#1064525 - 12/19/19 04:56 AM Re: Rear spring options for handling [Re: mmc427ss]  
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WAY to cold here the past few days and the wife keep reminding me we are a long way off from being done prepping for the holidays.
And my 20 year old Lincoln floor jack doesn't like the cold either. You have to pump it all the way up, then down, then up 20 times to get the cyl seals to behave. A rebuild kit is on the way.

Pulled the 02 SS throttle body off on Sun, corroded at the coolant areas of the alum mounting surface and probably weeping. Spend an hour block sanding the machine area to remove the erosion, it's pretty now. That fixed that likely candidate for a leak, good as new now. But still had a very small puddle in a depression at the last intake bolt #6 a day later. So will now continue searching for the culprit. The amount of coolant lost is very small, but I hate leaks.

Today after finally getting the floor jack to lift swapped the old Global rear springs back into the car. Two reasons, need to have a Ridetec and a UMI spring in hand to take to the rate checker, and needed to know what the old Global spring ride height is currently. It was 27" on the left side, the desired height. Now have all three spring's ride height measured at the same spring load (fuel load) and fitted.

The old Global springs are 27", with a stock pigtail rubber insulator top and bottom.
The Ridetec springs are 27", with a stock rubber insulator top and bottom, and a 1" plywood top spacer. Works great, but temporary.
The UMI F-body springs are 26 7/8" with a stock rubber bottom insulator, a 3rd Gen top insulator with a 1/4" rubber shim added. Easy to add another 1/8" to the ride height later but car is level, okay with that for now.

Won't have much play time with the car for a week or more now.
Bob

#1064526 - 12/19/19 05:46 PM Re: Rear spring options for handling [Re: mmc427ss]  
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SSLance Offline
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Merry Christmas Bob!!!


Lance
1985 Monte Carlo SS Street Car
#1064542 - 12/22/19 11:03 PM Re: Rear spring options for handling [Re: mmc427ss]  
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Chester Springs, PA
Just an FYI, for your consideration...

I just received a set of Moog-3229 to go with my front Moog-80908 units. The front ones have a 644# spring rate, and should drop the nose ~2.2 inches, while the rear will be right at 200# rate, and drop the rear ~3" (compared to factory height).

#3229 comes factory in the 97-06 Jeep Wranglers, and go for ~$55 shipped, on EBay. The front units are factory for the 06-10 Jeep Grand Cherokee SRT8, and also on EBay, for $84. To get ride height perfect, I'll use isolators for the appropriate vehicles in the desired thicknesses... allowing me to dial in height exactly where I want, without having to cut coils.

These might be sufficiently cheap options to expirement with... wink

#1064543 - 12/22/19 11:21 PM Re: Rear spring options for handling [Re: mmc427ss]  
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Guess who happens to have a set of OEM 2006 Jeep Wrangler springs sitting on his shelf? wink


Lance
1985 Monte Carlo SS Street Car
#1064544 - 12/23/19 12:01 AM Re: Rear spring options for handling [Re: SSLance]  
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LOL. :-D

#1064616 - 12/30/19 03:51 AM Re: Rear spring options for handling [Re: mmc427ss]  
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Eric, a note about very short springs and the lower mounts on the rear for the pigtail spring end. Easy to add height to that mount to keep/guide the spring from falling out there. 2 1/4" heavy gauge exhaust pipe is a perfect materiel to make it taller.

The 7 1/2" SS rear already has a taller mount, a cup, the same cup that bolts to the frame's spring mount at the top is welded to the top of a 7 1/2" rear's mount.. Only SS has that extra cup welded to rear spring mount. The rest of the 7 1/2" and all the 8 1/2" rears I've seen didn't get that extra height mod. When I installed the 8 1/2" a cup was welded on for the additional height with the shorter spring I was running. It was insurance against spring fall out.

When the Ridetec 12" spring I have gets fitted for their final time, which is after the shorter shocks show up, those tubes will get lengthened to keep the spring from dropping out of the rear mount. Also the upper spring cup will get lengthened for the same results, keep the springs from dropping out at full droop.

Here's a pic of what some 9" G-body rear venders do for that spring mount. Notice how tall the 2 1/4" tube is.
https://www.quickperformance.com/QP-GM-1978-1987-G-Body-9-Inch-Housing_p_10.html

Not much else done on the rear spring project. Need to setup a date to get the springs to the guy with the spring rater.

New seal kit installed in my 2 ton Lincoln floorjack, the ram seal was made of a plastic like nylon and was the problem, leaking past the seal. Also didn't help that over it's 25 years that jack was used hundreds of times while washing chassis, draining coolant and generally getting soaked. There was come water based sludge in the cylinder and reservoir. 55 bucks for a kit and it's like having a new USA jack again. Even the new ram seal had made in the USA on it. Merry Christmas.

Had the car out Sat for a 20 mile jaunt to charge the battery and change the fuel in the carb. At the end of each year the mileage is logged on all my vehicles. The 86 hit 168,748 the other day, so 2226 miles on the 86 in 2019. The goal is the same the past 10 years, try to drive it 2000. That 168K number really is only mileage on the paint and the driver's seat, the rest of the car is better than new.
Considering the 2019 projects done, door seal R&R, the Mcleod RST clutch install, the weld and mill the intake project, the rear spring project, the new wideband install, and another year of iffy weather putting 2200 on the car riding around the block, well priceless. It was build to drive it, it's a toy.
Bob

#1064662 - 01/04/20 07:51 PM Re: Rear spring options for handling [Re: mmc427ss]  
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MAP Offline
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Hi Bob,

Just curious if you could summarize:

1. What's good/what's bad when the springs are too soft?
2. What's good/what's bad when the springs are too stiff?

Try to remove the effects of shock dampening as much as possible.

Thanks,
MAP

#1064668 - 01/05/20 05:28 PM Re: Rear spring options for handling [Re: mmc427ss]  
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MAP not to the point in the project that I can assess the springs yet. Have had the two rear springs installed only for a minimal amount of time now. Both of the new springs are sitting on the bench right now waiting to get them on a spring rater to see where the progressive rates transition. That transition at what compressed length is important info for me to evaluate the springs.
Once I have that info the springs sets will go in for further testing and tuning.
Weather here in the NE is as expected for Winter, drive time is limited, wet roads, salt and that damn pretreat they put on the roads before an expected snow fall limits time the 86 spends out of the shop. Hard to evaluate handling under those conditions.

Have been talking with Viking shocks and in Feb they will have their new triple adj shock available. It will have high speed and low speed compression and rebound adjustments with out the reservoir common to triples, and at a much better price break than the shocks with reservoirs. Affordable to us retired seniors.
Having two compression adjusts should allow a higher rate rear spring without the harshness of a high rate rear spring. We'll see how that works out in the coming months. Also will be installing a 3/4" shorter rear shock to limit droop and possible spring drop out with the shorter free length rear springs.

A note on Ridetech, they were bought by Fox Shocks recently who as made Ridetech shocks for awhile now. Should mean the Ridetech shocks should only get better, which may be hard to do, improving something that is already a great product.

Last Thurs morning met up with Eric, Breathial's built thread here, for some Starbucks and bench racing time. He's playing with different springs on his 87 to achieve his goals. Eric is a smart boy and it's good to have someone locally to feed off of.
Bob

#1064674 - 01/05/20 10:23 PM Re: Rear spring options for handling [Re: mmc427ss]  
Joined: May 2002
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MAP Offline
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MAP  Offline
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Yuma, AZ
Hi Bob,

Well, I'm just trying to segregate the causes and effects you're seeing to figure out what spring stiffness works best. The right way to do this is with a design-of-experiment approach, but admittedly virtually no one who isn't an engineer would have the patience for that.

But if you're using non-linear springs with non-linear dampening, I'm afraid you've got a hopelessly complex ball of wax, so good results would be largely a function of good luck, of which I wish you a copious supply.

Every time I come to read here with my physics background, I literally shake my head and think that the right solution here is mass, not stiffness (dampening is tertiary.) But I also fully appreciate that solving the problem correctly would mean radical surgery to the car, of which few, if any, people would have the gumption to try. Hope springs eternal that I will be that person someday...

Best of luck again,
MAP




Last edited by MAP; 01/05/20 10:25 PM.
#1064695 - 01/08/20 04:45 AM Re: Rear spring options for handling [Re: mmc427ss]  
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mmc427ss Online content
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mmc427ss  Online Content
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Pottstown, Pa
MAP interesting read on droop. Not of any real value for what I'm playing with. But the extreme other side using droop to get around a corner faster.
https://racingnews.co/2020/01/07/droop-rule-announced-for-the-world-of-outlaws-late-model-series/
Bob

#1064738 - 01/09/20 10:05 PM Re: Rear spring options for handling [Re: mmc427ss]  
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MAP Offline
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MAP  Offline
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Hi Bob - thanks. Interesting, and I'm sure it has value within that narrow context, but it just strikes me as just another bandaid on a simple, tired solution. I'd much rather start with a clean sheet. There are solid, physics-based reasons for the consistent trend of moving away from rear live stick axles. But even if you stick with sticks, a higher ratio of sprung to unsprung mass on the rear axle will always help. The A/G body's 3:1 (ish) is dismal.

Best,
MAP

#1064771 - 01/14/20 12:27 PM Re: Rear spring options for handling [Re: mmc427ss]  
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St. Johns MI
What sucks is they're killing innovation at the top level of the sport, which will no doubt trickle into the weekly UMP stuff.

Those cars have gotten as aero dependent as cup cars, you can watch the nose shove right to the top of the track when they get in dirty air behind another car, combine that with a trophy truck style stacked springs on the LR & RF and 4 shocks on the rear end alone and you have some pretty advanced technology. All those guys have at minimum a spring smasher or even a shock dyno in the stacker now.

As expensive as its gotten the top level has grown a ton and I dont think you can find a better form of racing around.

What were we talking about??!?!


86 SS
400SBC, 4l80e, MSD Atomic injection/trans controller, Tilt glass clip, all tubular arms, corvette brakes, 9" rear
In progress
#1064811 - 01/18/20 06:14 AM Re: Rear spring options for handling [Re: mmc427ss]  
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mmc427ss Online content
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mmc427ss  Online Content
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Pottstown, Pa
Got a little side tracked on this project, chasing a lean cruise issue on the car for the past couple weeks. But haven't forgot about it.

Put a call into the guy with the spring rate checker but didn't hear back from him. Not sure which Intercomp rate checker he has but after looking at the specs on their 5000 lb checker there is only 4" of travel to check a spring rate. That's fine for a linear spring. It's rate should be the same from preloaded to 4" compressed. These two progressive springs to test are 12" and 13" free length and compress to about 8" at ride height. I would want to compress them to 7" or maybe less to plot their true rates from 7 to 11" compressed length. Don't think the Intercomp checker will work for me.

Speedway sells the Deco rate checker for very reasonable. Also sell 2000 lb if you need it. A range of 100 to 800 would be all that's needed for rear spring checking. The down side is max diameter of spring limited to 6", a stock G double pigtail spring and Ridetech spring are over 6" OD, probably won't fit.
https://www.speedwaymotors.com/DECO-Hydraulic-Coil-Spring-Rater-0-1000-Lbs-,231.html
The 2000 lb version would be an inexpensive rate checker for front coil springs though.

So now what to do, build one. While searching for an inexpensive 1000 lb scale, bathroom, digital or otherwise to use in a homemade rate checker I ran across this.
https://www.sherline.com/product/sherline-trailer-tongue-weight-scale/
Interestingly it's the same method of measuring rate as any other gauge coil spring rate checker, hydraulic pressure.

Today stopped at the large local RV trailer place for a chat about what they sell. They knew all about tongue weight and how important it is but didn't know anything about that Sherline. Drawtite sells the identical thing at over twice the price after I informed them of that, they could get me one. I'm guessing when you buy a new
travel home from them they are dry weight, who cares about tongue weight loaded. My brother-in-law found that out.

Have all the material laying around at the shop to build a checker. Looks like I'll buy a 1000 psi Sherline and use my floorjack as the compression method. Already have a drawing sketched out.. The bottle jack I have is to short to use. Looking to be only into this at the price of the Sherline, 130 bucks. For something that will get used for just a couple springs can't justify spending for one already made.

Couple years ago when the front suspension geometry was change built a bumpsteer checker to get accurate bump number, dial indicator I already had and also the Intercomp digital angle gauge, both used for the bump checker. Total cost was some MIG wire and gas.

It's not about the money for tools, it about making something that does what you need it to do.
Bob

#1064814 - 01/18/20 04:47 PM Re: Rear spring options for handling [Re: mmc427ss]  
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mmc427ss Online content
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mmc427ss  Online Content
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Pottstown, Pa
Just ordered a Sherline LM-1000 for the rate checker project.
I thought the name Sherline rang a bell. My father was a modeler, he bought a modeler's Unimat lathe many moons ago, it was not the best quality. Finally talked my mother into an upgrade lathe, the Sherline.
https://www.sherline.com/product/45004530-lathe/

Have used it several times to make parts for my car. Most recently when I did the body bushing project it was used to machine the poly bushings to my desired thickness and also the #1 and 2 delrin bushing that were machined to their desired thickness. Neat little tool to have at your disposal. Quality of that less than a grand Sherline lathe is very good, I suspect the LM-1000 to be as good.

As mentioned my brother-in-law bought a new travel trailer last year, an almost new F250 Ford was used to pull it. He just down sized the truck to a F150 with eco-boost which can easily handle the trailer, he got tired of the poor gas mileage and lousy ride of the F250. Won't he be surprised when I show up with the tongue weight checker for him to use?
Bob

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