Re: Rear Moog Spring choice

by bracketchev1221 Fri Apr 03, 2015 7:45 am

I am also considering the 5387. It just makes sense since I have 130 springs in the rear of my 3200 lbs race car. I couldn't see using a stock 126 rate spring. And yes the airbag is always an option because the passenger spring is the only one that tries to compress on launch.

by BBMALIBU Fri Apr 03, 2015 10:17 am

bracketchev1221 wrote:I am also considering the 5387. It just makes sense since I have 130 springs in the rear of my 3200 lbs race car. I couldn't see using a stock 126 rate spring. And yes the airbag is always an option because the passenger spring is the only one that tries to compress on launch.

But the 126 lb stock springs (5557) also have a free height of 16.76 inches.

5557:
Spring rate: 126.0 lb per inch
Free height: 16.76"
Installed height: 10.0"

Load to compress to 9.0" is 977.76 lb's
16.76" - 9.0" = 7.76"
7.76" x 126.0 lb = 997.76 lb

Load to compress to 10.0" is 851.76 lb's
16.76" - 10.0" = 6.76"
6.76" x 126.0 lb = 851.76 lb

It seems that it takes roughly the same weight to compress these 3 springs to a particular height (9" or 10").
I would have to guess that more spring coils equals a softer ride.

Moog lists a different installed height for each of these springs.
The 6381 is for a Wagon (9").
The 5557 std duty Coupe & Sedan (10.0") and 5387 HD Coupe & Sedan (8.5")

The rear of the our cars (Coupe) have a fixed weight.
If we used 2000 lb's as an example, all 3 of these springs should compress to roughly the same height of 9" (give or take .5")

Now at this point, it will take more or less weight to compress each spring because of their different spring rate.

This is why I think the 5387's are a compromise between everyday driving and the drag strip.

Does this make sense, maybe I am wrong or missing something?

by bracketchev1221 Fri Apr 03, 2015 10:39 am

You are right. 126 is super soft for that floating on air ride. But terrible for controlling the rear end movement when it tries to plant the tire. You want the suspension to extend to plant the tire and be stuff enough to control the rebound back up into the car. Ultimately adjustable shocks help with this but they can only do so much if the springs are too soft. Based on using a 130 at 3200 lbs I think a 157 is better considering 3700? Lbs.

by BBMALIBU Wed Apr 08, 2015 2:50 pm

bracketchev1221 wrote:Based on using a 130 at 3200 lbs I think a 157 is better considering 3700? Lbs.

How soon before you will be replacing the rear springs?

I am interested in the result.

by bracketchev1221 Wed Apr 08, 2015 3:12 pm

It won't be for awhile. I'm working on trying to get the 70 ready for this year. I'm going out to the track on the 18th with it. Its got all new adjustable shocks in it. Single adjustable Strange shocks in the front and double adjustable coil over Strange shocks in the rear. Just trying to get it more consistent in the hot weather.

by BBMALIBU Mon Apr 27, 2015 12:34 pm

I am currently replacing my rear springs with Moog 5387.

The original owner replaced the springs with HD one, and I was never sure exactly which ones.

Except for being worn/not straight and dirty, the old spring looks just like the 5387. Same amount of coils, same diameter (.61"), probably same height if it wasn't worn.

So I am happy with choosing the 5387.

I will try to post pic's soon.

by bracketchev1221 Mon Apr 27, 2015 8:32 pm

Better yet, let me know what the 60' times are at the track.

by BBMALIBU Mon Apr 27, 2015 10:24 pm

bracketchev1221 wrote:Better yet, let me know what the 60' times are at the track.

From memory: my car with the previous motor ran 12.63 @ 104mph with a 1.6 (ish) 60ft.

I am searching for the time slips.

by 76 Malibu Fri May 29, 2015 1:11 pm

I am thinking of replacing my rear springs on my car to get a bit more height in the rear. Right now I have Global West springs, which I think are about 170 in/lbs but not sure on any other specs. They sit pretty much at stock or maybe even slightly lower.

Have you guys looked at Caprice Springs? I found these two:

1991-96 Caprice HD Spring

#5419, 173 in/lbs, 16" free height, 9" load height with 1211 lb load

1990 Caprice Spring

#5395, spring rate 167 in/lbs, 15.52" free height, 10" install height with 901 lbs of load.

For the 5419 springs:

1038 lbs to compress to 10"

1211 lbs to compress to 9"

For the 5395 Springs:

921 lbs to compress to 10"

1088 lbs to compress to 9"

I am thinking of trying the newer Caprice springs.

Any thoughts?

by BBMALIBU Fri May 29, 2015 7:36 pm

76 Malibu wrote:I am thinking of replacing my rear springs on my car to get a bit more height in the rear.

A bit more than stock height?

I suggest the HD Coupe/Sedan MOOG 5387.

by 76 Malibu Fri May 29, 2015 7:59 pm

I don't think 5387's will give me anymore height. Plus, they are softer than what I have in the car now.

5387

Bar Diameter: 0.60". Spring Rate: 157.00 Lbs Per Inch. Load: 1089.00 Lbs. Installation Height: 8.50". Free Height: 15.42".

It takes less weight to compress these springs to a give height.

850 lbs to compress to 10"

1008 lbs to compress to 9"

Compared to the 5419 Caprice springs, if both have a 1000 lb load, the Caprice springs will sit about 1" taller.

by Joe73 Fri May 29, 2015 8:01 pm

Dont know if you have this but it makes it easy to look up and compare springs.

http://www.moog-suspension-parts.com/universal_coil_springs.asp

by BBMALIBU Fri May 29, 2015 9:54 pm

76 Malibu wrote: Right now I have Global West springs, which I think are about 170 in/lbs but not sure on any other specs. They sit pretty much at stock or maybe even slightly lower.

I figured you didn't know for certain about your current springs, except that it sits at or lower than stock. I have the 5387's and they definitely sit a little higher than stock (maybe 1").

How much above stock are you looking for?

by bigredlaguna Fri May 29, 2015 9:58 pm

You need to weigh the rear of your car then subtract the weight of the rear axle/wheel/tire assembly in order to get a reasonable estimation of how much a new set of springs will compress. If you have the rest of the specs for your current springs then an accurate comparison can be made between the new and current springs.

If nothing else, measure the compressed height of the current springs and an accurate weight.

by 76 Malibu Sat May 30, 2015 4:06 pm

Figuring out the rear weight then subtracting the unsprung weight is easier said than done. However, I did find that the stock springs have a load rating of 848 lbs. So I think this would be a reasonably accurate estimate on the load that would be on the springs.

I found this info (from the Moog site)

Stock 1976 Springs

#5557, 125.5 in/lbs, 16.76" free height, 10 inch installed height with 848 lb load.

1973 HD Springs

#5415, 170 in/lbs, 14.6" free height, 9 inch installed height with 950 lb load

1973-77 Station Wagon

#6381, 198 in/lbs, 14.34" free height, 9 inch installed height with 1062 lb load

1990 Caprice Spring

#5395, spring rate 167 in/lbs, 15.52" free height, 10" install height with 901 lbs of load.

1991-96 Caprice HD Spring

#5419, 173 in/lbs, 16" free height, 9" load height with 1211 lb load

Now to compare how the springs sit with the same load:

The stock 5557 springs are 10" tall with the 848 lb load.

The 5415 springs are 9.6" tall with that 848 lb load.

The 6381 wagon springs are 10.05" tall with an 848 lb load.

The 5395 Caprice springs are 10.4" tall with an 848 lb load.

The 5419 Caprice springs are 11.1" tall with an 848 lb load.

by 76 Malibu Sat May 30, 2015 4:17 pm

Joe73 wrote:Dont know if you have this but it makes it easy to look up and compare springs.

http://www.moog-suspension-parts.com/universal_coil_springs.asp

Thanks, that's a great tool!!

BBMALIBU wrote:
76 Malibu wrote: Right now I have Global West springs, which I think are about 170 in/lbs but not sure on any other specs. They sit pretty much at stock or maybe even slightly lower.

I figured you didn't know for certain about your current springs, except that it sits at or lower than stock. I have the 5387's and they definitely sit a little higher than stock (maybe 1").

How much above stock are you looking for?

I emailed them and they told me 169 lbs/in but didn't have any other specs. I am probably looking for about 1" lift, nothing major, just enough to improve the stance. I just don't want to go to a softer spring, the spring rates on the car are pretty good as is.

by bracketchev1221 Mon Jun 01, 2015 6:35 am

Have you tried looking at the Moog 6381 198 lbs/in spring.

by dynchel Mon Jun 01, 2015 6:40 am

I have the #6381's. I had a couple sets around for a while, stock replacements, s/w springs (6381 in currently) and a pair I bought years ago (speced for a '74 olds '98). The olds springs really put the "tail in the air" but rode like crap. What I found odd was the wagon springs only raised the rear about 1/2 inch over the stock replacements.

by bracketchev1221 Mon Jun 01, 2015 7:45 am

Also, how are the anti-squeak rubber isolators? If they are missing, you can put a set in and raise it about another 1/2".

by dynchel Mon Jun 01, 2015 7:51 am

I bought new energy suspension ones when I installed The springs.

by BBMALIBU Mon Jun 01, 2015 1:47 pm

[/quote]
bracketchev1221, I believe the 6381 (wagon) and 5387 (HD Coupe & Sedan) springs are pretty close.

5387:
Spring rate: 157.0 lb per inch
Free height: 15.42"
Although it states 8.5" for installed height, I will use 9.0"

Load to compress to 9.0" is 1007.94 lb's
15.42" - 9.0" = 6.42"
6.42 x 157.0 lb = 1007.94 lb

Load to compress to 10.0" is 850.00 lb's
15.42" - 10.0" = 5.42"
5.42" x 157.0 lb = 850.00 lb

6381
Spring rate: 198.00 lb per inch
Free height: 14.34"
Installed height: 9.0"

Load to compress to 9.0" is 1057.32 lb's
14.34" - 9.0" = 5.34"
5.34" x 198.0 lb = 1057.32 lb

Load to compress to 10.0" is 859.32 lb's
14.34" - 10.0" = 4.34"
4.34" x 198.0 lb = 859.32 lb

They seem pretty close to me. I am strongly considering the 5387 for my Malibu.
Since I have the air bags, I can always just pump the right rear up at the track.[/quote]

Besides spring rate per inch, you should consider the free height of the spring.

Note that the MOOG 5387 & 6381 both require about the same weigh to compress
to the installed height (9" or 10"). Yet the 5387 has a 157 lb rate compared to the 6381's 198 lb rate.

Both of these springs will sit a little higher than the stock springs (126 lb rate)

I would stay away from the Caprice's springs, only because I have seen a few posts where the G3 sat way too high using them (owners were not happy). Just do a google search.

by Wallyuph Mon Jun 01, 2015 8:52 pm

Has anyone used Moog cc507. (cargo coils) I have no clue what springs are in my car I got them with the front end parts from this guy (see photo of the guy I got them from below).

I was thinking of trying them.

Rear Moog Spring choice - Page 2 <a href=

Rear Moog Spring choice - Page 2 <a href=

Rear Moog Spring choice - Page 2 Spring10

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Last weekend I had 4 large guys in the car and the rear pass side rubbed on the tire. Not on corners but just when we hit bumps going straight. I jacked it up when I got home and found the upper adjustable control arm lock nuts were loose so rear end was not straight any more and that why it as hitting on pass side. Had moved in 1 & 3/4" Also explained while when we hit a bump it wanted to kick out to pass rear. They are even now and tight. I'll check them after a few miles and if they loosen up I'll have to put some lock tight on them. I may have just missed tighten up the lock nuts on that side when I installed them.

Still did a heck of a good burn out with all of us in the car and rear end jacked. Ha

by 76 Malibu Mon Jun 01, 2015 10:20 pm

bracketchev1221, I believe the 6381 (wagon) and 5387 (HD Coupe & Sedan) springs are pretty close.

5387:
Spring rate: 157.0 lb per inch
Free height: 15.42"
Although it states 8.5" for installed height, I will use 9.0"

Load to compress to 9.0" is 1007.94 lb's
15.42" - 9.0" = 6.42"
6.42 x 157.0 lb = 1007.94 lb

Load to compress to 10.0" is 850.00 lb's
15.42" - 10.0" = 5.42"
5.42" x 157.0 lb = 850.00 lb

6381
Spring rate: 198.00 lb per inch
Free height: 14.34"
Installed height: 9.0"

Load to compress to 9.0" is 1057.32 lb's
14.34" - 9.0" = 5.34"
5.34" x 198.0 lb = 1057.32 lb

Load to compress to 10.0" is 859.32 lb's
14.34" - 10.0" = 4.34"
4.34" x 198.0 lb = 859.32 lb

They seem pretty close to me. I am strongly considering the 5387 for my Malibu.
Since I have the air bags, I can always just pump the right rear up at the track.

Besides spring rate per inch, you should consider the free height of the spring.

Note that the MOOG 5387 & 6381 both require about the same weigh to compress
to the installed height (9" or 10"). Yet the 5387 has a 157 lb rate compared to the 6381's 198 lb rate.

Both of these springs will sit a little higher than the stock springs (126 lb rate)

I would stay away from the Caprice's springs, only because I have seen a few posts where the G3 sat way too high using them (owners were not happy). Just do a google search.

I don't see how 5387's would sit much higher than stock springs. The stock springs sit at 10" with 848 lbs, while the 5387's are 10" at 850 lbs. If we are replacing OEM spring, they may have sagged which may be making up for the height difference.

I tried to find posts about the Caprice Springs, but I can't find anything.

I may end up trying the Caprice springs, I think they will be the best option for a decent spring rate and stance.

by 76 Malibu Tue Jun 02, 2015 8:52 pm

Rear Moog Spring choice - Page 2 1976_c11

I found the original factory spring specs for the 1976 Chevelle. The only issue is that I don't know which cars got what. These are for all models, including wagons and El Caminos.

by dynchel Wed Jun 03, 2015 6:58 am

Rear Moog Spring choice - Page 2 IMG_20150601_145006481_zpsddpq4hqe

If anyone is interested, this is the stance the station wagon springs (6381)will give you. The tires are 295/50/15's rear & 215/70/15's front

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