Lowering '84 911
05-28-2005, 05:39 PM
#1
Wallflower
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Lowering '84 911
The more I look at my '84 vs. others here, I'm thinking I'd like to lower it a bit (per several suggestions on my initial post when I bought her). I can't go too low as I do have a pretty steep driveway, but I am interested in seeing what it takes.
I ordered 2 books when I got the car... the Bentley manual and 101 Projects... 101 Projects seems to be on backorder and I'm not sure when it'll be here. While I'm waiting, I've been trying to find more info on what it takes to lower an '84, but I haven't found much info on the steps to take... lot's of discussion regarding what the height should be and the difference between front and rear. I have noted that I should look at turbo tie rods and perhaps a bump steer kit.
Just wondering if anyone has any links to some writeups on the subject.
TIA!
I ordered 2 books when I got the car... the Bentley manual and 101 Projects... 101 Projects seems to be on backorder and I'm not sure when it'll be here. While I'm waiting, I've been trying to find more info on what it takes to lower an '84, but I haven't found much info on the steps to take... lot's of discussion regarding what the height should be and the difference between front and rear. I have noted that I should look at turbo tie rods and perhaps a bump steer kit.
Just wondering if anyone has any links to some writeups on the subject.
TIA!
05-29-2005, 10:42 AM
#3
Properly lowering your 911 is a fairly complex endeavor. When I say "properly", I mean the lowering should be done in conjunction with a corner-balance and a 4-wheel alignment.
I lowered my '84 Carrera about 5 years ago. I then took it to a shop to be corner balanced and aligned. I got lucky, my corner weights were fairly close, so the technician was able to tweek the corner heights using the front adjusting bolts and the rear height adjusting eccentric on the radius arm.
In summary, the actual lowering involves lowering the suspension height at all four courners. In addition to the basic handtools, you need a accurate protractor that reads angles and you need a good steel tape measure. Start by taking baseline measurements - I measured the height from the garage floor to the apex of the fender lip at each corner. I then measured the rake of the car using my angle protractor on the door sill; I had a 1% rake (nose down) that I wanted to maintain. Finally, determine how much you want to lower the car. I my case, I dropped each corner about 1 inch.
The front corners are relatively simple. There is a adjusting bolt on each torsion bar end cap. You turn the adjusting bolt in either direction to adjust the front corner height up or down.
The rear height is much more involved because you must re-index the rear torsion bars. This step is all about angles. You need to take a baseine measurement of the loosened radius arm angle (i.e. 37 degrees). Based on a trig formula, you can determine what new angle you need to achieve the desired rear height (i.e. 34.5 degrees). When you remove the radius arm off the end of the t-bar, carefully count the number of splines you rotate the radius arm. There is documentation on the web as to how many degees of angle each spline repesents. Keep in mine there are a different number of splines on the inside vs. outside of the t-bar. As you can imagine, lowering the rear is very time consuming and takes a lot of patience.
Once you get the rear radius arm angles where you want them, put the rear suspension back together, lower the car and bounce the suspension around to settle things. Then measure the corner heights again...I had to go back and do the rear height again because the car settled more than I anticipated. Lastly, I took the car to a Porsche shop to be corner balanced and aligned.
This project is doable for the average home wrench with the proper tools and a lot patience. It would make things go smoother if you had someone helping you that had experience in lowering a 911.
Look around the web, because I have seen several tech articles that take you through the process step-by-step. Have Fun!
I lowered my '84 Carrera about 5 years ago. I then took it to a shop to be corner balanced and aligned. I got lucky, my corner weights were fairly close, so the technician was able to tweek the corner heights using the front adjusting bolts and the rear height adjusting eccentric on the radius arm.
In summary, the actual lowering involves lowering the suspension height at all four courners. In addition to the basic handtools, you need a accurate protractor that reads angles and you need a good steel tape measure. Start by taking baseline measurements - I measured the height from the garage floor to the apex of the fender lip at each corner. I then measured the rake of the car using my angle protractor on the door sill; I had a 1% rake (nose down) that I wanted to maintain. Finally, determine how much you want to lower the car. I my case, I dropped each corner about 1 inch.
The front corners are relatively simple. There is a adjusting bolt on each torsion bar end cap. You turn the adjusting bolt in either direction to adjust the front corner height up or down.
The rear height is much more involved because you must re-index the rear torsion bars. This step is all about angles. You need to take a baseine measurement of the loosened radius arm angle (i.e. 37 degrees). Based on a trig formula, you can determine what new angle you need to achieve the desired rear height (i.e. 34.5 degrees). When you remove the radius arm off the end of the t-bar, carefully count the number of splines you rotate the radius arm. There is documentation on the web as to how many degees of angle each spline repesents. Keep in mine there are a different number of splines on the inside vs. outside of the t-bar. As you can imagine, lowering the rear is very time consuming and takes a lot of patience.
Once you get the rear radius arm angles where you want them, put the rear suspension back together, lower the car and bounce the suspension around to settle things. Then measure the corner heights again...I had to go back and do the rear height again because the car settled more than I anticipated. Lastly, I took the car to a Porsche shop to be corner balanced and aligned.
This project is doable for the average home wrench with the proper tools and a lot patience. It would make things go smoother if you had someone helping you that had experience in lowering a 911.
Look around the web, because I have seen several tech articles that take you through the process step-by-step. Have Fun!
05-29-2005, 12:08 PM
#4
Wallflower
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Thanks! I could have sworn I looked on Pelican too, but didn't see it.
Bruce... good summary. I lifted my Jeep with the help of a friend, but that was incredibly simple. I figured this would be a bit more involved, and it sounds like the rear definitely is. I'll have to mull this over a bit and decide if I want to tackle it myself or get my mechanic to handle it for me.
Bruce... good summary. I lifted my Jeep with the help of a friend, but that was incredibly simple. I figured this would be a bit more involved, and it sounds like the rear definitely is. I'll have to mull this over a bit and decide if I want to tackle it myself or get my mechanic to handle it for me.
05-29-2005, 07:30 PM
#5
Legacy Flounder
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So Bruce, need any friends? 
The way you describe sounds an awful lot like trying to adjust reground camshafts timing in a multi-cam engine, with sprocket "A" controlling in ±7°, Sprocket "B" controlling ±3°, and you tweak them each accordingly to get the overlap you want - not much fun while you're doing it, but rewarding when completed.
The way you describe sounds an awful lot like trying to adjust reground camshafts timing in a multi-cam engine, with sprocket "A" controlling in ±7°, Sprocket "B" controlling ±3°, and you tweak them each accordingly to get the overlap you want - not much fun while you're doing it, but rewarding when completed.
05-29-2005, 08:16 PM
#6
Fred,
You are so right, lowering the car is tedious work. But the end result is well worth it!
I think adjusting reground cams is a tougher job though. If you can properly time your cams, lowering your ride height will be a "cake walk".
You are so right, lowering the car is tedious work. But the end result is well worth it!
I think adjusting reground cams is a tougher job though. If you can properly time your cams, lowering your ride height will be a "cake walk".
