armyboyatc

iTrader: (29)

I was on another website where they were telling a guy how to set his suspension up. They told him to take his springs that he had off (dont know what # springs they were) and run a 150# spring.... I read that if it was a full weight (or close to) car then 375 - 300lb spring is what you need. I have read a lot about this on here so I questioned it and this is the answer that I got.

"We're reccomending that, because it's a lot closer to what he actually needs than what those generic/off-the-shelf coil-over kits come with. The aftermarket companies would rather put you on too stiff of spring and not create any gains, vs putting you on too light of spring which could bottom out under certain situations and cause ill-handling.

I can guarantee you those 300's are barely compressed sitting at ride height, thus have almost no stored energy to help you launch. - Even though they are marketed as "drag-race" coil over kits, they often do not work as well as stock springs for that reason.

When he had coil-overs on the stang, Robert had the 175# springs that came with his Steeda "drag race" kit on it. With nothing more than a tube k-member and an aluminum block, the adjusters were basically fully down and the car rode like a chuck wagon; the springs were compressing less than 2" total at ride height and thus had next-to no stored energy. - I have a blown BBC tall-deck full of concrete, plus a 6 gallon fuel cell sitting on my front end. Even with that kind of front end weight I run 10" 175# springs, but only because I use 1-2 of down travel and thus don't need the extra store energy. If I ran a lot of travel like most street cars I would run 12" 150's."

This goes against everything that I have read on here. Can someone explain this to me? Is he wrong or is the research that told me I needed to run a 275 - 300lb spring wrong? Help me out here fellas.

Sorry for the long post, im just trying to learn.

Trey

armyboyatc

iTrader: (29)

Seriously? No one has an answer for this?

repo

iTrader: (2)

ssvert99

iTrader: (26)

I can't see any way a spring less than a 275 rate will work on the front end of f-body, unless it has some serious metal removal, an aluminum block, and lightweight body parts. the 150-175 springs are what we use on the front of the Mustangs which are a completely different suspension. the most common spring for the f-body cars is the 300 and the heaviest we ever have used is a 325.

chrs1313

iTrader: (24)

agreed 275 spring here and works like a charm...I cannot see another spring rate being lighter either, considering my springs are 75% compression up the shocks to get stock ride height now

xpndbl3

iTrader: (23)

3rd gen springs are typically 170-200 for their front drag race coilover setups. I know in my thirdgen I'm running a 12" 170 pound spring, might step it up to a 14" 175 pound at the most, we'll see how this is in a month or so.

358chevycamaro

iTrader: (10)

I ran a 275lbs spring with my Strange SA drag struts and it worked killer. Sold the combo to a friend who had a 403 iron block motor in the car and you could obviously tell the spring was having more trouble with the extra weight and relied on the strut to do the springs job. It worked and was a definite improvement over the factory parts, but a 300lbs spring would have let the strut do it's job better since it wouldn't have to work as hard to keep the front end as stable especially at the launch.

Racecars or race application parts are not always a one size fit all piece. If you want to know what spring you will benefit from the most, get the car to the ride height desired and then weigh the car with 4 corner scales and consult your shock/spring manufacturer. I can guarantee you that they will be able to give you the proper advice as what will perform the best especially when compared to a redneck on a online forum that thinks he is an engineering genius (like the one you're referring to).

5.3LJimmy

iTrader: (10)

The springs are rated at a xxxlb per inch of compression. So a 300lb spring will need to compress 3" to hold a 900lb corner weight and a 150lb spring on the same car would need to compress 6". This is probably close to bottoming out a 12" tall spring. Speaking of bottoming out... I installed a set of coil overs with a 275lb spring on a friends full weight 01 TA with an LQ9. The 275lb spring is almost completely compressed and the shock is out of adjustment just to get the front high enough to drive the car safely.

Obviously there must be a difference in the mustang suspension that requires less spring weight. I don't know b/c I've never worked on one. It appears that you may be comparing apples and oranges as far as the discussion goes on the other forum. If the Steeda kit quoted does come with a 175lb spring then it seems feasible that a 150lb spring may work better in a drag car as it will store more energy.

armyboyatc

iTrader: (29)

So are mustangs really that much lighter than our cars? I cant see the suspension being THAT much different.

BlackScreaminMachine

iTrader: (17)

Fox Body cars are a whole different beast and the race weight on their worst day is near our best day.

275 is the Min you should go and like said some weight reduction is sometimes required. If running Iron blocks or any FI such as Turbo or Supercharger, 275 w/o other reduction is a no, no.

I run basically stock weight in the front, either Skinnes or 17" WS.6 rims but on my QA1 R-Series I have a 315 spring or something along the lines of a LT1 spring and I even had to max out the ride height with the cups.

A Major PITA for that setup.

armyboyatc

iTrader: (29)

Ok I got ya. 2 different cars, 2 different set ups. Thanks for clearing that up guys. I need to stay off those other sites. They are making me question you guys haha.