Was looking at UMI Upper and lower control arm kit for 1970 Cutlass for $1200 and then saw OPGI upper and lowers for $970. Anyone have UMI or OPGI? Interested in your experiences and opinions.

Street only... big block. 575 HP. 3.90 rear.will have TKX. would start with stock shock/spring and eventually go to Viking Coil overs.

Thanks

 

OPGI is not a manufacturer. You can probably find out who really makes that kit, or it might be the generic no-name stuff which you can buy from anyone. The generic stuff can work, but you have to do your own QA. e.g, I had to replace bushings and balljoints in my no-name tubular a-arms.

 

UMI used on mine, straight forward installation, no complaints.

 

Give these guys a call.. Sales & Tech Support: 813-986-9302

They have a scratch and dent sale going on now on the A-Arms you need.. they are the manufacturer..

I just bought some shocks for a car and a set of Vi-King Coil Overs for another..

Good luck,

Thirdcoast

 

Cost is just part of the tube size, wall thickness , design, strength.

Look at Detroit Speed from drop spindle to adj coil overs and in between.
Proven handling packages.

 

Actually, BMR (FL) has been in business a bit longer than DSE (SC).. but both make very good parts and sell most major brands that they do not mfg. such as Vi-King.

 

Just realized BMR is only 90 minutes from me. I think it’s time for a road trip.

 

DSE, Global West, BMR, and UMI all make good products. They all have different packages targeted at different price points and customer goals. Some of the packages address the poor camber curve of the A-body front suspension, some do not. The lower cost packages do not fix the suspension geometry issues.

In my opinion, if you do not fix the geometry, you are wasting money on control arms. You can simply buy and install Global West Del-aluminum bushings in the OEM control arms for less than half the price. Also, Do not use polyurethane bushings, they bind and make things worse, not better.

I would stay away from OPGI, CPP, and others that source a lot of their parts from China. A lot of the parts are also poor knockoffs of other U.S. made vendors.

 

THANK YOU ALL!! Exceptional advice, as expected here!!!! Thanks for taking the time to help.

 

Looking at BMR they do not show drop spindles or coil over shocks at part of packages.

 

And? So what if they don’t? Please explain why this is or is not important in terms of suspension design, performance, and geometry.

First point to start with is that all 68 -72 GM A-bodies left the factory with essentially a coil over front suspension. The coil spring is located around the shock allowing the shock to better control the springs compression and rebound vs. a divorced shock and spring like what is used on the rear live axle.

 

The drop spindle changes the geometry for better handling along with adjustable coil over shocks that allow for ride height adjustment and response.
Did not see BMR offer these options.
Just a comment and info.

 

 

Ok, I thought that might be where you were going.

Drop spindles do not change the front suspension geometry. They move the wheel mounting point (i.e. king pin) higher which will lower the front of the vehicle without loosing any suspension travel.

DSE uses a taller spindle which does change and improve the front suspension geometry. DSE's spindle also happens to to have relocated the wheel mounting point higher to lower the vehicle without loosing suspension travel. Its not the placement of the wheel mounting point which changes the geometry, it's the increase in spindle height.

BMR, SPC, and a number of other companies accomplish the same thing with factory style spindles. Specifically, BMR and SPC use taller ball joints which both change the suspension geometry and lower the front of the vehicle. By using a taller lower ball joint, from a geometry standpoint you are effectively making the spindle longer and moving the wheel mounting point higher. The taller lower ball joint also moves the steering arm higher which reduces bump steer in A-bodies. I suspect that DSE changed the location of the steering arm in their spindle to help reduce bump steer.

Basically, there are a lot of ways to accomplish the same goals. DSE uses a taller spindle with a relocated wheel mounting point while others may use taller ball joints with a factory style spindle. Lowering the front of the vehicle without loosing suspension travel can also be accomplished by relocating the spring pocket on the lower control arm. SPC does this with their lower front control arm. You can place shims in the SPC spring pocket to adjust ride height without changing suspension travel.

You want to be careful setting ride height by using the adjuster on an coil over such as what DSE, Vicking, Chassis Works and others offer. The shock only works correctly in a limited range of adjustment. If the installer is not careful, they can lower the vehicle and compress the shock too much at static ride height causing it to bottom out during bump or roll - which will result in front end understeer and a harsh ride. The real reason to get a set of adjustable height coil overs is to corner balance the vehicle so that you can get side to side and cross weights at each tire as close as possible. But, most people don't have the tools or knowledge to corner balance a vehicle correctly. Coil over vendors hype ride height adjustment because it sells product and they know most of their customers know nothing about corner balancing and optimizing the suspension setup.

Most people will adjust a coil over so that the ride height is equal on the driver and passenger sides. This is not the correct way to install the coil over. Adjusting ride height in this manner will inadvertently cause weight jacking (i.e. an uneven distribution of the car's weight on one of the tires) and a decrease in handling performance. What you want to do is determine ride height on one side and then set the other coil over at exactly the same position on the adjuster. You then proceed to corner balancing the car. Once complete, the car will very rarely sit at the same ride height at each corner. But, it will handle better because you more evenly distributed the vehicles weight to each of the tires.

 

hmmm sounds like some Mark Savitske suggestions/info/knowledge. He's been getting lots of bad press lately but I did everything he suggested on my 442 and I'm extremely happy with the results. No coil overs on my ride for the exact reasons mentioned above. I had them on the front and took them off. Went with the AFX spindles and aluminum steering arms, SPC springs front and rear, SPC upper and lower arms, progressive rate jounce bumpers, chassis brace, Lee 800 12.7:1 steering box, varishock dbl adjustable shocks all the way around, and the Correctrac upper and lower rear arms with the 30 degree articulating johnny joints. The ride is unbelievable - geometry issues resolved (both suspension and steering) bump steer gone, steering feel is unreal both driving slow in a parking lot doing tight turns or hard competitive cornering. Spring rates are 550/135 = smooth ride for cruising. No reason for high rates springs with this setup even for competitive autocross/road racing. It's a ton of money for all this but it's unbelievable how my 4000 lb convertible 442 handles and drives now. Plus everything is fully adjustable for easy street driving, straight line drag racing, or autocross.
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Wow 71OLDS. Thanks for sharing your awesome setup. Never would have known this approach! Thanks. Checked out prices on Summit....very expensive.

 

1968-72 Chevy Chevelle Tubular Control Arm & Coil Over Suspension Kit, Stage 3+, 3 Plus (performanceonline.com)

anyone know about performance on line suspension products? Great price.....is it great value?

 

Looks like your tire rubs your sway bar .

 

Yes it did. That was just a good pic of the new setup before we made additional mods. That Hotchkis sway bar was cut in half and about 1" was removed from the middle that keeps it tight against the frame now.
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It actually provides more turn in clearance lock to lock then the splined bar you show in your pic above. I was going to purchase one of those if the mods on the Hotchkis bar didn't work.
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