New Buick Suspension!

The Buick hasn’t had much done to it in the last year or so. With it being gone six months to Saudi Arabia over the ’19-’20 winter, and me racing the Probe mostly last year, the Buick’s been basically sitting and doing a great job of holding the garage floor down.

But that changes today. Thanks to a program with FM3 Performance Marketing, QA1 Motorsports has decided to sponsor the Buick this year. Now, this sponsorship didn’t come with any strings, I didn’t sign a contract agreeing to anything, it was basically a discount program. So, I get to tell you the truth about my experience with this kit.

But the discount was HUGE. So, a big thank you to QA1 for the opportunity.

I opted for a full “level 2” kit (HK22-GMG1), minus the front control arms. QA1 does have a front control arm offering, but they’re Delrin bushed, and if you’re a longtime reader, you’ll know my car melts Delrin in the front control arms pretty quickly, so I kept my existing rod-end bushed control arm package. The QA1 front coilovers work with all of them.

I gave QA1 scale data on the car, and they picked out the spring rates and got the kit on the way. It showed up in five boxes of shiny. If you do not have scale data on your car, find somebody and get your car weighed before calling QA1. The corner weight data is invaluable to them. They can turn that into proper spring rates so you don’t have to guess or play the trial and error game.

A lot of QA1 suspension parts
Pile of shiny

After getting all that, it was time to load it in the trunk and head to my Dad’s shop so I could use his lift.

First order of business is always removing the old stuff. Since we were doing rear suspension, it was a balancing act. We had several kits to install:

  1. Lower control arms
  2. Upper control arms
  3. Coil-over shocks and springs
  4. Sway bar

QA1 ships all four of these as independent self-contained kits, so figuring out what order to do it all was up to us. The control arms themselves need to be replaced one at a time to keep the rear end from rotating in a manner that would cause us a problem.

Of course, there were issues. The original control arms were, um, trashed. The bushings on the chassis side on all four had spun in the housings:

But that’s OK. It’s old. This was the original suspension. I did replace the bushings about seven years ago, but a lot of hard miles have gone on this thing since then.

What surprised us was the upper control arm bushings in the axle ears. They were in fantastic shape even though the chassis side wasn’t. Because those bushings are a giant pain in the ass to change, and we weren’t going to use the poly axle side bushings provided in the kit because they wouldn’t be compatible with the Fayes2 Watts link, we left them in.

After replacing all of the arms one at a time, we got to the coil-over shocks.

Some install notes:

We had to enlarge the holes for the upper shock mounts and the control arm pivots. The QA1 kit came with SAE hardware instead of metric, so some stuff was just a hair off. Nothing a which hone using a drill bit couldn’t fix. The lower shock mount brackets also do not have accommodations for LCA relocation to help with instant center. We actually relocated the LCA pivot point down an inch last year, but it wouldn’t fit that way anymore. Our solution was to put the LCAs back to the stock locations, but raise the rear end a quarter inch. This combined with a slightly lower front ride height should help keep the instant center somewhat close to where it was. We’ll have to take some measurements and see.

Coilover shock and spring assembly
More shiny

The rear swaybar was an easy install as well. I do like their mounting system. Instead of bolting the arm directly to the lower control arms, it bolts some pillow block brackets to the arms that the bar slides into. There aren’t any holes drilled in the bar itself.

Interesting pillow block installation for this thing.
Buick on wooden stands
Crib blocks makes everything better

With all the new rear suspension in place, we sat the car down on these crib blocks I made. They get the tire contact patch 18″ off the ground, which is plenty of clearance for me to craw underneath while the car was sitting with all of its weight on the suspension. We were able to set the rear ride height, pinion angle, and re-set the Watts link. Once all the adjustments were done, we torqued all the bolts to spec and moved on to the front.

One more note on the rear, and a bit of a reality check: None of it was difficult, but you have to be methodical. Leave any fasteners involved in a pivot point snug but not tight until you have them all in, then set the car on the suspension and tighten. Most of the important nuts in the kit were either nylock or oval-type lock nuts. We backed that up with blue Loctite both on the pivots and and chassis mounts to keep stuff from shaking apart.

If you want to be absolutely sure, you could swap the nuts out for Mil-spec flex tops or drill everything for wire locks, but this isn’t a helicopter and we didn’t have that much time.

The kit also came with these trick braces:

Suspension Brace
Suspension Brace

They tie the chassis side rear control arm mounts together on each side. They’re adjustable because no two of these cars are the same.

With the adjustable rear suspension, we were able to set the ride height, fix the pinion angle, which threw the Watts link out of whack, but we fixed that too. Moving on to the front, this kit uses a novel pigtail front spring so you can put a coilover into a stock location spring pocket. This prevents having to cut and weld on the upper frame to install a properly reinforced upper mount. When this system first came out nearly twenty years ago, a lot of people passed on it because they only had two spring rates available. That is no longer the case. They now have springs in rate increments of 50 lb/in going from 400 to 700 pounds!

assembled front coil over
Assembled front coil over

Back to the scale data: this was a spot where I was initially concerned. Through trial and error, I had arrived at 700 lb/in springs in the front of my car, but after looking at the scale data, QA1 recommended a 600 lb/in spring instead. That’s a pretty big difference. I went with their recommendation.

Getting the front apart was easy. Get the car i the air, disconnect the tie rods and break the lower ball joint loose. Swing the lower arm out of the way to free the coil spring, and use a block of wood under the upper control arm to get the spindle assembly out of your face. Remove the nut retaining the shock, and out it comes.

Installation of the new stuff is the reverse of assembly, except you’ll want to install the spring on the shock first, then slide the entire assembly into the frame pocketc. Put the upper shock and bushing onĀ  the top finger tight, then you can swing the lower control arm back into play and loosely fit the lower ball joint back into the spindle. Finally, run some new hardware through the lower shock T-bar to secure the coilover to the lower control arm.

Here’s a pro tip. In the picture you see the shock assembly with the spring perch run all the way down. This was to make installation easier. We didn’t have the compress the spring to get the nut on the top of the shock started. Where we screwed up was we didn’t raise the perch before bolting it all together and setting the car down. It ended up WAY too low. Not wanting to take it all apart, we simply tried to use the spanner kit QA1 sells to run the perches up and raise the car’s nose.

It. took. for. ever. The QA1 spanners are not good. They’re these things that attach to a 3/8″ drive breaker bar. They were very difficult to work with. I highly recommend buying a proper set of coilover spanners. They’re available for less than $30 online.

But, we got there.

With all that done, it was off to Dream Street Motorsports for the alignment. With the ride height corrected and a lot of finageling, we got the alignment exactly where I wanted it.

screen from an alignment machine
How much caster? All of it!

With the alignment set, we waited for the last piece to show up: The custom built carbon fiber driveshaft.

Now, I’m now stranger to some physics. I understand the impact of spinning mass on vehicle dynamics. If you’ve ever played with a gyroscope, you know that a mass that’s spinning resists motion more than mass at rest. That means that on a car, when you reduce the mass of something that spins, it has an outsized effect compared to dead mass. In the case of a car, removing one pound from something that spins at engine speed is roughly equivalent to removing 50x that much of dead weight from the car in terms of handling dynamics. You also gain tremeduously in terms of reduction in parasitic losses, and lighter parts are easier on bearings. In the case of a mass that spins at the output shaft speed, you get a 15x benefit.

So, talking about the stock steel driveshaft. It’s a 2.75″ diameter tube and I have upgraded Spicer 1310 greasable u-joints installed. An OE shaft equipped as such is good for 400lb-ft of continuous torque and can absorb ~800ft-lbs for short intervals. The tube itself is likely fine to much higher numbers, the weak link is usually the U-joints.

This is important. I haven’t dyno’d the car properly yet, but the data I do have indicates the car makes at least 400hp at 3500RPM. Applying the formulat for torque and horsepower backwards, that works out to 615lb-ft at that RPM. That’s in a situation where the car has 2500 RPM left to go in it’s sweep. I’m basically begging for a u-joint failure on this car.

So, I spec’d out my QA1 driveshaft with the large 3.2″ tube, SFI certification, and the massive Spicer 1350 U-joints, and a forged billet chromoly steel output shaft yoke.

 

Carbon fiber drive shaft next to the OE steel shaft
QA1 Carbon Fiber driveshaft

Fully assembled, this new shaft is 3.8 pounds lighter than the stocker, even after adding the much beefier yokes to it. I also replaced the pinion yoke on the differential with Yukon gear unit to accommodate the larger U-joints.

After all this work, how does it all, well, work?

I have to say I’m impressed. Just driving on the street, the ride quality is much better. The lower spring rate makes the ride much less harsh, but the shock adjustability makes it work. I can tune out the dive and roll with the adjustment. Following the QA1 recommendations, I ran 6 clicks on compression and rebout in the front on the street. In the back, the springs are a bit stiffer than my old ones, so I’m running just 2 clicks in the rear.

So, it’s better on the street. What about when driving in anger? Well, I finally got to an autocross. The course was punishingly tight, which is a worst case scenario for a car this size. I have to say, the drive mod needs some work, but the car? The front end bite is fantastic. I turn the wheel and it went. I found myself turning early for stuff because I was expecting understeer that didn’t happen. Tire wear in the front was completely even, with rollover exactly at the indicators with the tire at 35psi, which is street pressures.

This was a 33.7. On the next run after this one, we threw the serpentine belt, so I’ll have to figure out what’s up with that. But, at the point where the belt went, I was a full second faster already, so a 32.7 was definitely on the table. A less tight course that doesn’t require so much steering input will show more. Keep an eye on this space.

We have a time trial coming up, so stay tuned for videos of that. Our previous best on NCM’s Grand Full layout is a 2:32. If I can break into the 2:20s, I’ll be estatic. Like and subscribe on the Youtubes and Instagrams, @inkyracing, and you’ll know immediately if we hit the goal!

One last thank you to QA1 and FM3 for the opportunity here. I’m excited to see where this car stacks up now.

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