Modifying Your Front Upper Shock Mount
10-08-2008, 08:46 AM
#1
Modifying Your Front Upper Shock Mount First of all, why do this?
It's not going to lower or raise or change your ride height at all. What this mod does is move the shock higher up inside the spring about 3/4" and the result is that you will gain 1.25" in compression travel. Meaning the tire will tuck higher. At the same time, you loose the exact same distance in droop. Meaning the tire will not drop down as far when jacked up. What this does is give your lowered car more suspension travel and that means a smoother ride and more cornering grip. All of which lowered cars need.
It's kind of like a poor mans shock shortening.
(EDIT: If you want to lower the front of your car about 1" without having to buy new springs and shocks, then read post #49.)
Here are some before and after pics of my car with no springs, only the shocks and the weight of the car fully compressing the bumpstop.
BEFORE
AFTER
Now the front upper shock mount is a big mystery to most because it does several things in one complex package.
1. first, the outer part supports the spring and the weight of the car. As the suspension moves up and down the angle of the spring ends change. This is no big deal as the spring itself will bow left and right slight to compensate.
2. The triangle or trapezoid part inside is what the shock bolts to. It captures the shock preventing it from pulling and pushing so that it can do it's job properly.
Now remember that the spring can bow and flex as the suspension moves up and down. The shock on the other hand can not. It can only extend and collapse, not bend. Bending a shock can be very bad. It may be a little hard to picture, but when the lower control arm is level, the lower shock mount is farthest from the engine. As the arm moves up and down, the lower shock mount gets closer to the engine. Since the bottom part is moving in an out, and the upper shock mount is fixed in one position, it has no choice but to want to tilt. If it can't tilt, it will bind up the shock or even bend the shaft.
3. So the GM engineers designed the inner part of the upper shock mount to be able to tilt slightly.
When you modify the upper mount, you have to make sure it is still able to tilt a little without binding and you will see that I took care of that.
I have to give credit to "John" for showing me this. He uses it on his race car. I don't know of anyone else doing this, although it may be a bit of an inside secret. I hope not.
It's not going to lower or raise or change your ride height at all. What this mod does is move the shock higher up inside the spring about 3/4" and the result is that you will gain 1.25" in compression travel. Meaning the tire will tuck higher. At the same time, you loose the exact same distance in droop. Meaning the tire will not drop down as far when jacked up. What this does is give your lowered car more suspension travel and that means a smoother ride and more cornering grip. All of which lowered cars need.
It's kind of like a poor mans shock shortening.
(EDIT: If you want to lower the front of your car about 1" without having to buy new springs and shocks, then read post #49.)
Here are some before and after pics of my car with no springs, only the shocks and the weight of the car fully compressing the bumpstop.
BEFORE
AFTER
Now the front upper shock mount is a big mystery to most because it does several things in one complex package.
1. first, the outer part supports the spring and the weight of the car. As the suspension moves up and down the angle of the spring ends change. This is no big deal as the spring itself will bow left and right slight to compensate.
2. The triangle or trapezoid part inside is what the shock bolts to. It captures the shock preventing it from pulling and pushing so that it can do it's job properly.
Now remember that the spring can bow and flex as the suspension moves up and down. The shock on the other hand can not. It can only extend and collapse, not bend. Bending a shock can be very bad. It may be a little hard to picture, but when the lower control arm is level, the lower shock mount is farthest from the engine. As the arm moves up and down, the lower shock mount gets closer to the engine. Since the bottom part is moving in an out, and the upper shock mount is fixed in one position, it has no choice but to want to tilt. If it can't tilt, it will bind up the shock or even bend the shaft.
3. So the GM engineers designed the inner part of the upper shock mount to be able to tilt slightly.
When you modify the upper mount, you have to make sure it is still able to tilt a little without binding and you will see that I took care of that.
I have to give credit to "John" for showing me this. He uses it on his race car. I don't know of anyone else doing this, although it may be a bit of an inside secret. I hope not.
Last edited by JasonWW; 11-03-2008 at 03:52 AM.
10-08-2008, 08:47 AM
#2
I want to say a word of caution before I get too far into this.
This mod allows the front tires to tuck in higher than stock. It's basically removing the safety margin the factory designed into the front suspension. Kind of like a factory suspension alignment that causes premature understeer. If you like pushing your car hard, you probably already switched over to a performance alignment with more negative camber. This is a similar situation. Your pushing things to the limit.
So make sure you have room in the wheel well for the tire to go up further. I removed my plastic liner to keep it from rubbing. You can probably mod your liner or else let the tire slowly rub a hole in it. It probably won't hurt anything.
It also maxes out the angle on the upper ball joint. Ideally you'd want to change the upper ball joint angle slightly to match it's new range of motion, but that's pretty serious work. I think it should be fine as is. It hasn't proven to be a problem.
Now if this gives you too much travel and you want to reduce it slightly, you can add packers to the shock so the bumpstop makes contact sooner. Packers are great to have on hand. Here is a pic of the thin white discs next to some bumpstops.
In fact, you can stack up 3/4" of them on the shock rod and be right back to where you started, but have 1.25" less droop. Then remove one packer from each side and take the car for a drive. If it the tire doesn't rub the liner, remove one more per side. As you do the ride quality will get better. When the tire just starts to rub the liner, either stay there or put one pair of packers back in. It's all up to you.
After the mod my upper a-arm has about 1/4" clearance from the shock tower and the wheel itself has about 3/8" clearance from the shock tower. Keep in mind that my tires are a tad taller than stock.
(EDIT) Here is a basic breakdown of how the upper shock mount holds the spring and shock. Since we are only modding the inner blue portion, the ride height is not effected at all.
This mod allows the front tires to tuck in higher than stock. It's basically removing the safety margin the factory designed into the front suspension. Kind of like a factory suspension alignment that causes premature understeer. If you like pushing your car hard, you probably already switched over to a performance alignment with more negative camber. This is a similar situation. Your pushing things to the limit.
So make sure you have room in the wheel well for the tire to go up further. I removed my plastic liner to keep it from rubbing. You can probably mod your liner or else let the tire slowly rub a hole in it. It probably won't hurt anything.
It also maxes out the angle on the upper ball joint. Ideally you'd want to change the upper ball joint angle slightly to match it's new range of motion, but that's pretty serious work. I think it should be fine as is. It hasn't proven to be a problem.
Now if this gives you too much travel and you want to reduce it slightly, you can add packers to the shock so the bumpstop makes contact sooner. Packers are great to have on hand. Here is a pic of the thin white discs next to some bumpstops.
In fact, you can stack up 3/4" of them on the shock rod and be right back to where you started, but have 1.25" less droop. Then remove one packer from each side and take the car for a drive. If it the tire doesn't rub the liner, remove one more per side. As you do the ride quality will get better. When the tire just starts to rub the liner, either stay there or put one pair of packers back in. It's all up to you.
After the mod my upper a-arm has about 1/4" clearance from the shock tower and the wheel itself has about 3/8" clearance from the shock tower. Keep in mind that my tires are a tad taller than stock.
(EDIT) Here is a basic breakdown of how the upper shock mount holds the spring and shock. Since we are only modding the inner blue portion, the ride height is not effected at all.
Last edited by JasonWW; 07-05-2010 at 10:23 AM.
10-08-2008, 08:48 AM
#4
(IGNORE THE EXPRIMENTAL BUMPSTOP IN THIS PICTURE)
You have to cut off the nub or else it will hit the sheetmetal when you go to install the shock. It's not a big sacrifice.
I got the spacer seperated from the rubber by heating it. 
That's basically it.
Guys running Koni's will only need to leave off the large flat washer from the top of the tophat. The tapered shape on it will allow for it to tilt. So no washer needed for those.
Here is the upper shock mount, the trapazoid shaped piece and the upper control arm assembly. The trapazoid piece is directly bolted to the shock and gets traped in between the 2 bigger pieces.
Here it is a stock Koni shock.
Here are all the pieces together in stock form:
Here is everything after the modification.
The pink trapazoidal piece stays locked into place and controls all the up and down forces the shock gives it, but it still has enough give to allow the shock to tilt slightly.
Now for the guys running Ground Control coilover conversions, you can do this too! There's just one more extra step you have to take, but it's not too hard. I'll talk about that later.
I've got stock, Koni and Ground Control parts on hand, but I don't have any other shocks like Bilsteins, etc... I'll have to take a look at the shocks to see what needs to be changed if anything. Once I get that info, I'll update this thread.
One last note is that the stock front bumpstops can be reshaped to be more progressive. I'm hesitant to post any info on this right now as I'm still working on the right shape.
One more shot of my car with the modded mount.
Last edited by JasonWW; 07-03-2009 at 07:43 AM.
10-08-2008, 01:59 PM
#5
wow and i thought i was a badass when i lowered my car 1.75" and had it still ride decent.
looks pretty good man. i think you're one crazy f*ck, but i have always admired your ideas and the fact that you actually have the ***** to try them. i could never personally tear into my car like that. glad someone out there is crazy enough to come up with new ideas
looks pretty good man. i think you're one crazy f*ck, but i have always admired your ideas and the fact that you actually have the ***** to try them. i could never personally tear into my car like that. glad someone out there is crazy enough to come up with new ideas
10-08-2008, 02:09 PM
#6
wow and i thought i was a badass when i lowered my car 1.75" and had it still ride decent.
looks pretty good man. i think you're one crazy f*ck, but i have always admired your ideas and the fact that you actually have the ***** to try them. i could never personally tear into my car like that. glad someone out there is crazy enough to come up with new ideas
looks pretty good man. i think you're one crazy f*ck, but i have always admired your ideas and the fact that you actually have the ***** to try them. i could never personally tear into my car like that. glad someone out there is crazy enough to come up with new ideas
Oh yeah, with this mod it would ride like it was only lowered 1/2". Cool, huh?
Last edited by JasonWW; 10-08-2008 at 02:16 PM.
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10-08-2008, 03:09 PM
#8
I may be warping your mind with this mod, but a spring swap is still a spring swap.
10-08-2008, 10:44 PM
#12
Sure, if your rules allow it. This mod originated on a road race car to make better use of the available suspension travel. An unfair advantage? Maybe. I guess if no one contests it, you'll be ok.
Nothing is weakened, the weight of the car and the spring mount is unchanged. The shock can still tilt up top and it's still captured just like factory.
It's still up to the individual to make sure he doesn't get too much of a good thing. You'll need to check for tire rub just like you do when running a 315 rear tire. This is actually easier than all the stuff needed to fit a 315 and look at all the folks doing that.
I actually see racers as more likely to do this. For a street driven car not pushed to the limits, a smoother ride is what you'll notice most.
Nothing is weakened, the weight of the car and the spring mount is unchanged. The shock can still tilt up top and it's still captured just like factory.
It's still up to the individual to make sure he doesn't get too much of a good thing. You'll need to check for tire rub just like you do when running a 315 rear tire. This is actually easier than all the stuff needed to fit a 315 and look at all the folks doing that.
I actually see racers as more likely to do this. For a street driven car not pushed to the limits, a smoother ride is what you'll notice most.
Last edited by JasonWW; 03-11-2009 at 11:44 PM.
10-08-2008, 11:16 PM
#14
Total shock stroke is about 3.75". Multiply that by the 1.7 motion ratio and you end up with right at 6" of wheel travel. This never changes.
Last edited by JasonWW; 10-08-2008 at 11:22 PM.
10-08-2008, 11:33 PM
#15
either way, cool stuff.
10-09-2008, 10:55 AM
#19
Yeah, it's free, but a lot of work. Not so much if your already taking the springs apart. I've taken them apart back and forth switching shocks, bumpstops, mounts, etc... for pictures and measuring that I'm sick of it. I'm taking a little break from it at the moment.
Oh, and definetely use a bandsaw to cut them. I used a angle grinder with a cutoff wheel and the rubber melts, stinks, smokes and gets slung all over your hands, arms and clothes. Not fun.
Oh, and definetely use a bandsaw to cut them. I used a angle grinder with a cutoff wheel and the rubber melts, stinks, smokes and gets slung all over your hands, arms and clothes. Not fun.
