Need lessons learned on lowering a 911
 

I am getting ready to tackle on lowering my 930 based on Vu's photos. From the photos, seemed like the hard part was removing the old bushings. The front seemed easy but need a bit more info on the rears. I spoke with Pari this weekend and he has plans as well. Pari, maybe we can use your car as a guinnea pig before I tackle mine :wink:

I know Charlie is a pro in this project already but hate to ask him for help since he's been to all Project help thus far. :oops: I may just need some advice or lessons learned from Vu's car. Vu, since you got Charlie's training on lowering your car. Any advice or assistance? I kept a link form Charlies spring plate calculator but not sure of the weight of the car.

Jon:

Are you going to replace the spring plate bushings or just lower the car??

What is the ride height now, and where do you want it to be??

What size tires are you running?

If you are not changing torsion bars there is an easy way to lower the car.

Jack up car remove wheels and remove lower shock bolts, the two bolts attaching the spring plate to the control arm and the 2 adjuster hex head bolts and nuts. Support the control arm. (btw if you have Bilsteins or gas charged shocks record the amount the car drops when they are removed as you will need to factor this in when you do the lowering measurements)

Push the spring plate down as far as you can and scrib a line along the top of the spring plate on the fender.

Measure from the ground to the lowest point of the spring plate (under the lower bolt hole that goes to the control arm) and record the measurement.

Remove spring plate replace bushings and center the adjuster on the spring plate. You will need a 36mm and 24mm wrench to loosen the adjuster bolt and set bolt.

When you go to replace the spring plate add the amount you want the car lowered to the first measurement and move the spring plate on the torsion bar splines until you reach that measurement.

Bolt everything together except the shocks. Drive the car slowly a few feet and check the hieght. If you have gas shocks attach them. Check ride hieght. You should be withiin 1/2" of your goal, which can now be fine tuned with the spring plate adjuster. When using the adjuster the car goes up when the plate goes up and visa versa. (This is opposite from the spring plate adjustment on the torsion bars . . . spring plate up car down).

Jon,

Marc pretty much summed it up...but if you need more details, pm your number and we'll chat. It wasn't very difficult, but having Charlie guide me through it was a major advantage.

Personally , I found the hardest part was loosening all the bolts. Once you got them loosened, it was pretty straight forward.

I'll be away until Fri, but I'll be checking my emails.

Two words: "PB Blaster" :)

or,

Two more words: "BFH" and "Torch" :lol:

Jase

Use a large breaker bar and strategically place its end on a jack. Use the hydraulic jack to break the bolts free. My 150lb frame can't break a cracker :roll:

Marc, thanks for taking the time to write down the detailed instuctions. I have printed this out and will go by this to tackle this project. I have lots of tools and a huge compressor to try to tackle this task. I'll try to use an impact wrench to break bolts loose and/or help from a torch like Jase said. Always had good success with a Mapp torch. It's the procedures I'm not sure off.

Are you going to replace the spring plate bushings or just lower the car??
I will possibly replace the bushings. Is this recommeded? I planned to since I saw pics from Vu's.
What is the ride height now, and where do you want it to be??
I have no idea what the ride height is. I would guess 27" from ground to fender.
What size tires are you running?
235/40/18 front & 285/35/18 rear.

Marc / Vu, I will PM you guys to for additional advice.

Are you going to replace the spring plate bushings or just lower the car??
I will possibly replace the bushings. Is this recommeded? I planned to since I saw pics from Vu's.

If the gap between the torsion bar cover and the bushing cover is not equal all the way around, then it is time for new bushings


What is the ride height now, and where do you want it to be??
I have no idea what the ride height is. I would guess 27" from ground to fender.

measure from ground to highest point in the arc of the fender on front and back . . . shock travel is where I'm going here

What size tires are you running?
235/40/18 front & 285/35/18 rear.

looks like your OD is about 25.7" . . . again I'm thinking shock travel . . . with those wheels/tires you should be able to go as low 25/25.5 without any shock problems, probably will need rack spacers. 24.5/25 would require testing of shock bumber clearance

Marc, I just measured the rear and shows 25.75". I'm looking around 25" on all four corners. Sorry, what's OD?

We can do mine first Jon, just take good notes :wink: . I am still undecided whether or not to upgrade my stock bilsteins with some HD's in the front and bilstein sports in the rear. Chances are it will eventually get added to my why I ran out of money cause I was in there list. If I replace the OEM shocks, does this mean I will need to replace the torsion bars. Marc thanks for the detailed instructions they will definitely come in handy.

"OD"= overall diameter.

25/25.5 is prefered to give the car a rake forward. Although, scales are the only way to be sure, 25" all the way around will probably make the rear a little light.

With a .75" change the spring plates will have to come off for re-indexing on the torsion bars.