I debating between running one of these two front springs on my Thunderbird. It has a 5.0 with aluminum heads and the smog pump/Thermactor system removed. It does still have functioning A/C. With the stock Thunderbird LX springs front springs and 225/55/16 tires the car has about 3 inches of clearance between the top of the tire and the fender lip. I would like to drop that about 1.5 inches or so. I'm stuck between the MOOG 8598 spring (87-93 5.0 Mustang replacement) or the MOOG 8594 spring (99-04 Mustang GT replacement).
MOOG 8598: http://www.oreillyauto.com/site/c/detail/MOO0/8598/03360.oap?year=1981&make=Ford&model=Mustang&vi=1133446&ck=Search_03360_1133446_-1&pt=03360&ppt=C0361
MOOG 8594: http://www.oreillyauto.com/site/c/detail/MOO0/8594/03360.oap?year=1999&make=Ford&model=Mustang&vi=1354744&ck=Search_03360_1354744_-1&pt=03360&ppt=C0361
Both springs have virtually identical free and installed heights but the 8598 springs have a slightly higher load rating and In/lbs rate. I'm thinking that the 8598 is the way to go but I'd like some thoughts first.
BTW I did use the search function for both of these springs. I couldn't get a concrete answer either way.
Those kind of look basically like stock replacements to me, but with lousy (low) spring rates. It's been a minute since I've had a stock spring in front of me to compare those specs to, but neither would get the green light from me. Those rates look like base/V6 range stuff.
The only upside is that they're linear rate, so if you do go with the heavier of the two, and the car sat a bit high, you could trim the springs a bit (from the bottom) to get the ride height where you like it.
I know V8Demon is running the 8598 spring in the front of his car (5.0 aluminum heads) which is why I've been leaning towards them. Do you have a better suggestion? I'm fine with the stock rear springs but ever since I swapped on the aluminum heads my Thunderbird has sat about .75-1 inch higher in the front.
They're V8 rates. If you're worried about the height on the 8598 you could check out the 8600.
http://rs280.pbsrc.com/albums/kk191/V8Demon/Car%20Tech/MoogSpringsspecsheet-1.png
http://rs280.pbsrc.com/albums/kk191/V8Demon/Car%20Tech/MoogSpringsspecsheet-2.png
I don't know if the links will work as I'm posting from a mobile device.... Lemme know and I'll fix if need be.
Also, from when I did my initial research: http://www.foxtbirdcougarforums.com/showthread.php?19115-TC-springs
Looking through your thread Kitz ran the MOOG 8600 springs with an aluminum headed 5.0. Didn't lower the car much at all (maybe 3/8"). It looks like I'm going to be picking up a set of 8598s. It looks like they should drop the front of my Thunderbird about 1.5 inches, which would be perfect. The 8594 springs look like they would drop the nose way too much. When I swapped on the aluminum heads the nose of the car went up about an inch from the weight reduction. I'm just trying to get it back to where it was with iron heads.
I think you may be happy with Vinnie's setup. His stance is really nice. I don't remember specifics, but I think he had a recent thread on it.
Comparing the replacement springs for an 88 Thunderbird LX:
MOOG 8658: http://www.oreillyauto.com/site/c/detail/MOO0/8658/03360.oap?year=1988&make=Ford&model=Thunderbird&vi=1140310&ck=Search_03360_1140310_3405&pt=03360&ppt=C0361
With the replacement spring for the 87-93 5.0 Mustang (spring V8Demon runs):
MOOG 8598: http://www.oreillyauto.com/site/c/detail/MOO0/8598/03360.oap?year=1981&make=Ford&model=Mustang&vi=1133446&ck=Search_03360_1133446_-1&pt=03360&ppt=C0361
The 8598 springs have the same spring rate and only a 35lb less load rating. Plus the installed height is .75 inch shorter. That should be enough to drop the nose of my Thunderbird down 1-1.5 inches. Exactly what I'm looking for. I think I'm going with the 8598 spring unless someone has a better idea.
Couldnt you just trim a little of the current springs you have?????
= free
From what I've read that screws with the spring rate. Plus new parts are cool ;).
That is only if the springs are progressive rate. If they are a linear rate spring then chop away.
Darren
Ah that's how it goes. I'm still going to get the 8598 springs though. With basically the same load rating and rate and being .75" shorter they should do exactly what I want them to.
There are so many different spring rates.from the factory depending on option packages one would have to consult there door tag and get a hold of some info on stock spring rates and part numbers direct from Ford. AFAIK, this has not been done for our particular cars. Closest thing I can find is that Moog chart I posted.
Example: The 2005 Mustang had SEVEN different front springs that it could possibly have come with depending on engine, transmission, and other options. The end goal was to make height as close as possible across the line for all of the different combinations.
That's the thing I'm not sure exactly what springs are in my car. All I know is that the MOOG replacement ones are close to the 8598 springs but the 8598 springs are about .75 inches shorter. Hopefully that lowers the front 1-1.5 inches (lowering the gap between the top of the tire and fender from 3 inches to 1.5-2 inches, matching the rear).
Just for comparison purposes: MOOG 8598 springs on the left, 88 Thunderbird Turbo Coupe with automatic springs on the right.
They are almost the same height.
I've got the later model springs on mine, the fronts were new from Moog, but the rears were salvaged. I like my stance, but with aluminum heads, you'd be at that .75 drop you're looking for, maybe just a bit more. With iron heads, I've dropped almost 2, maybe 1 7/8
http://www.foxtbirdcougarforums.com/showthread.php?37723-lowering-springs&p=436498#post436498
Hopefully the 8598 springs drop the nose down 1-1.5 inches or so. It went up about 1 inch with the aluminum heads. I'll find out in the spring when I swap the stock front springs out.
I put the MOOG 8598 springs in today. They dropped the nose down about an inch. Previously there was about 3.5" between the top of the tire and the fender lip in the front of the car. The 8598 springs dropped the nose down so there is 2.5" between the top of the tire and the fender. That matches the rear which has 2.5" of space between the top of the tire and quarter panel lip. The stock LX V8 springs were approximately 1 inch taller than the 8598 springs. The 8598 springs are the same height as Turbo Coupe springs. So apparently Turbo Coupe springs "should" work in the front of an aluminum headed 5.0 car.
Before:
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/20150407_0922241_zps3hz9hcrc.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/20150407_0922241_zps3hz9hcrc.jpg.html)
After:
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/20150409_212722_zpsodfcuyqi.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/20150409_212722_zpsodfcuyqi.jpg.html)
Before:
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/webt2_zps8cc8bea6.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/webt2_zps8cc8bea6.jpg.html)
After:
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/20150410_153819_zpspl9aseut.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/20150410_153819_zpspl9aseut.jpg.html)
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/20150410_153753_zps4cyajht4.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/20150410_153753_zps4cyajht4.jpg.html)
The Thunderbird now is the same height as my wife's 2012 Mustang. Which is good.
For comparison purposes stock Turbo Coupe (with automatic) front spring on the left and stock LX V8 front spring on the right. The Turbo Coupe front spring is the same height as the MOOG 8598 spring I used.
(http://i198.photobucket.com/albums/aa33/thunderjet302/Thunderbird%20web/20150409_212321_zpsgifvgjzv.jpg) (http://s198.photobucket.com/user/thunderjet302/media/Thunderbird%20web/20150409_212321_zpsgifvgjzv.jpg.html)
One could probably get away with cutting one coil off the stock V8 LX front spring when swapping to aluminum heads. My car probably has close to 100lbs less weight over the nose since it no longer has iron heads, cast iron exhaust manifolds, or the Thermactor system. The car still weighs 3560 with no driver. It probably was close to 3660 stock with no driver, hence the taller spring.
The ride of the car with the MOOG 8598 springs hasn't changed and in fact feels better than with the stock front springs.
But you have to take into consideration spring rates. They may end up the same height but there could be differences in performance. If the springs rates are the same or very close and the type of spring is the same (variable vs linear) then the comparison makes sense.
Darren
True. I went with the MOOG 8598 spring as several people have used it with success so it was a know quantity.
Rates are almost identical FWIW. 415-425 lbs/in.
I'm surprised you aren't lower. You running stock Arms? What size tire?
03 Cobra Front arms, Prothane spring isolators, 225/55/16 tires. Maybe it will settle over time.
I think that some of you guys are confusing spring rates and loaded ride height rating here, which are two different things. You can certainly have two or more different springs with the same rate but different ride height. When Ford specs out the springs for a certain model of car, there can be 5+ different springs as mentioned, all with the same spring rate. However, the weight needed to compress it to the ride height spec is different ... that's what they use to tune the height when there is added weight from extra options, etc.
Up until the 1970s, on the Ford parts microfiche catalogue cards, the various part numbers of springs would be listed in charts showing the spring rate, and the weight spec to compress the spring to ride height. Even through the 80s, the info would be published sometimes, but I haven't seen anything like that from Ford for many years, unless it's in a technical service bulletin for ride heights on a truck.
Here's an example ... the 87-93 Fox 5.0L Mustangs all had the same spring rate (except the 93 Cobra), but there were about 7 different OEM front springs, and 5 or 6 for the rear. This was to make up for the range of weight variations from a stripper no A/C 5-speed coupe, to a hatchback, to a GT hatchback with a bit more weight, all the way to a loaded up AOD ragtop car with A/C. This is typically done by adding a bit more free height to the springs. The old Ford Motorsport M-5300-C spring kit for the Mustangs were just LX coupe base rear springs, and 5.0L Fox LTD police package no A/C springs. I remember looking at the tag IDs on them in the late 80s when I had my 87 LX hatch and was starting with the mods on it.
So the long and short of it, comparing spring rates between various springs isn't going to give you a direct indication of how the ride height will come out.
cheers
Ed
No, but the charts I posted links to earlier up will.....