cutting springs to lower car

[warrenrhen]

I've replaced my bumpers with Vics bumperettes. Now I want to lower the whole car slightly and get the back more level with the front. Nothing radical just a nie street car. I'm thinking one coil in the back and a 1/2 coil in the front. Anybody have experience with this? How much will that lower the back? and will Need shorter shocks?
Cheers Warren

[redcars]

You will not need different shocks. How much you need to take off will depend on your car and your tastes. I would go with a half coil at a time. The back springs are easy to take in and out. The fronts are more of a challenge. Be sure to get a spring commpessor.

[RRoller123]

Reading about this over the years, the general consensus seems to be to do this very little at a time, and not take too much. 1/2 turn is a good start, may be a good stopping point too.

[jon8christine]

When I cut my rear springs to level out the car I took either 1 coil or maybe 1-1/2 off the rear w/ the bumpers removed. I did it in stages as others have mentioned. A few years later I redid all the suspension for autocross and bought Allisons lowering springs...just right.

[TheBender]

I decided to get Allison’s lowering progressive springs and new shocks. Love both the height and also the improved ride quality.

[profcucchi]

I gave this a lot of thought, too.

A Fiat and Alfa mechanic told me once you cut springs, you throw off the geometry of the vehicle. and it makes for a stiffer ride.

I decided to hold out until I could get proper lowering springs.

[redcars]

Lowering springs do the same thing, it just costs you more. I have did both. Now that I am old I have went to stock Springs and wheels for the nicer ride. When I want very good handling and a harsh ride I get out the Super 7 replica.

[seawood]

"I gave this a lot of thought, too.

A Fiat and Alfa mechanic told me once you cut springs, you throw off the geometry of the vehicle. and it makes for a stiffer ride.

I decided to hold out until I could get proper lowering springs."

In my opinion, spot on. Good choice. If you can spring for Koni's, do so, you won't regret it.
Being an older engine, I have finally come to the realization that I will never achieve push back in the seat performance, even after spending close to 5G on the engine. I have a stage 2 Golf R , same displacement, for that.(385hp) However the handling can be jigged to offer a great experience in the twisties. I have the old IAP red springs, non chopped, and the Koni's. Car sits nicely. I added a larger front sway bar and a rear bar. Went to 15 inch wheels with 205/35? 15 tires.
Not seat back performance but I do notice I will be feeling the side to side while cornering. Fun stuff with the top down.

[Nut124]

I gave this a lot of thought, too.

A Fiat and Alfa mechanic told me once you cut springs, you throw off the geometry of the vehicle. and it makes for a stiffer ride.

I decided to hold out until I could get proper lowering springs.

Lowering the car by cutting springs is not a good idea. The cut, shorter springs are too soft to prevent bottoming out in hard bumps.

When lowering the car, the shorter spring must be a lot stiffer in order to keep the suspension from bottoming out with much reduced travel. Cutting springs does not make them stiffer, the opposite.

[18Fiatsandcounting]

Lowering the car by cutting springs is not a good idea. The cut, shorter springs are too soft to prevent bottoming out in hard bumps.

When lowering the car, the shorter spring must be a lot stiffer in order to keep the suspension from bottoming out with much reduced travel. Cutting springs does not make them stiffer, the opposite.

Good to know, Nut, thanks for that. In the back of my mind, I always had this sense that cutting springs was not a good idea, but I couldn't pinpoint why. Besides, with some of the abrupt driveway entry angles and tall parking lot bump stops around here, the last thing I need is a lower car...

-Bryan

[Nut124]

Lowering the car by cutting springs is not a good idea. The cut, shorter springs are too soft to prevent bottoming out in hard bumps.

When lowering the car, the shorter spring must be a lot stiffer in order to keep the suspension from bottoming out with much reduced travel. Cutting springs does not make them stiffer, the opposite.

Good to know, Nut, thanks for that. In the back of my mind, I always had this sense that cutting springs was not a good idea, but I couldn't pinpoint why. Besides, with some of the abrupt driveway entry angles and tall parking lot bump stops around here, the last thing I need is a lower car...

-Bryan

I did a little more research on this and will need to admit I was wrong. Cutting a spring shorter does actually increase the spring rate. Whether, in this case, the increased spring rate is enough, or too much, to compensate for the reduced suspension travel or not does not seem easy to calculate.

[18Fiatsandcounting]

I did a little more research on this and will need to admit I was wrong. Cutting a spring shorter does actually increase the spring rate. Whether, in this case, the increased spring rate is enough, or too much, to compensate for the reduced suspension travel or not does not seem easy to calculate.

Ahhh, Nut, you're a smarter man that I.
I'll have to think about this some more, but I guess it makes sense if you think of an extreme: Take an imaginary car spring that is 10 feet long. You could probably pretty easily compress it by hand by one inch. Now cut that same 10 foot long spring so it is only 6 inches long. It would take a lot more force to compress it by one inch, so effectively the spring rate has increased.

In effect, cutting the spring decreases the amount of coils available to flex, so it takes more load to deflect a similar amount, that is, the spring rate has gone up.

However, with cut springs you have to make sure that 1) the ends of the springs still fit as they are supposed to, and 2) lowering the car doesn't cause other effects like stress on your suspension, alignment, ground clearance, etc. For a performance setup, fine. For casual driving on roads with potholes and steep driveways and such, my choice has always been to leave it stock.

Meanwhile, this guy seems to know what he is talking about:
https://www.eatondetroitspring.com/cutt ... culations/

-Bryan