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Progress Tech Springs + Koni = 2+ inch drop in the rear

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Old 02-23-2010, 02:03 PM
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Progress Tech Springs + Koni = 2+ inch drop in the rear

Okay, so I have spent the better part of two days reading here, and haven't come across an answer (that I can understand at least) to my question yet.

I installed a set of Progress Tech Sport Springs and a set of Koni sport shocks and the rear suspension dropped a lot more than I expected (a little more than 2 in). the front ended up right where i expected it to (down about 1.5 in). Everything seems to be working fine, and the car doesn't bottom out on uneven pavement or when running over bumps in the road, it is just sitting crazy low in the back. After reading through these two threads I am even more confused.
https://www.rx8club.com/showthread.p...nsion+problems
https://www.rx8club.com/series-i-wheels-tires-brakes-suspension-55/rear-too-low-stock-spring-koni-shock-wtf-131498/
My question is: Is anyone else running this Koni + Progress combo with diferent results from what I have. It seems (from reading through the threads above multiple times) that some springs don't work with other struts, and I wanted to know if that is the case with my combo.

I definitely didn't do enough research before I made this switch (I did read a few threads here, but not enough of them I guess).

I will post some exact measurements when I get home tonight (measured from the ground to the wheel well) and plan on jacking the car up to see if the rear springs are binding.

Any thoughts would be welcome.
Old 02-23-2010, 02:10 PM
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Lets see some pictures.
Old 02-23-2010, 02:31 PM
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Did you load the suspension before you tightened the upper mounting points?
You can manipulate the ride height quite a bit that way.
Old 02-23-2010, 02:41 PM
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Wow, thanks for the quick responses.

Originally Posted by TopGear8
Lets see some pictures.
I will take some when I get home from work.
Originally Posted by MazdaManiac
Did you load the suspension before you tightened the upper mounting points?
You can manipulate the ride height quite a bit that way.
No I didn't. I can't get under it when it is on the ground. I have a few cinder blocks at the house and I was thinking about jacking the car up and setting both the rear wheels on the blocks to allow me to get under it while having the suspension sitting with the weight on the wheels. Does this sound like it will work? However I would think that not preloading the rear would cause it to ride to high, which is opposite of the problem that I am seeing. Or are you thinking that the front is not dropping and that is what I am seeing and misidentifying as the rear being too low?
Old 02-23-2010, 02:48 PM
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You don't need to get under it - just put a jack under the wheel spindle and crank it up before you tighten the bolts on the upper arms. That'll drop the front.
Old 02-23-2010, 04:19 PM
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Thanks again for the quick response. I can't find my camera but I did take some measurements out on the driveway (pretty level). All measurements were taken from the ground through the center of the rim and to the bottom of the wheel well. Not scientific I know.

Front Left: 26.5 inches (about 1 in gap between wheel and wheel well)
Front Right: 26.5 inches

Rear Left: 26 inches (no gap at all)
Rear Right: 26 inches

The whole set up appears to have settled in the front a bunch since I saw it yesterday. It was dark this morning when I went to work so I didn't get a good look at it until this afternoon. I did the work on Saturday and I remember the front measuring at least an inch higher (I didn't write it down). I came home to a garage in shambles, it seems my wife chose today to clean out and reorganize it, so I doubt I will have a chance to work on the car this evening. She is wait on me know to help with the rest of the cleaning/reorganizing. Married life is bliss! Her timing is amazing, I can't even get my car in the garage right now. Did I mention that its like 30 degrees and the forecast calls for snow tonight.

Last edited by Solidtrance; 02-23-2010 at 04:25 PM.
Old 03-04-2010, 11:08 AM
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Update: the front has settled fully now, and it is sitting much more level. there is still a slightly larger gap in the front, but it not noticable at all. i had an allignment done last week and everything is good. I will put up pics as soon as I take some. Thanks again for the help.
Old 03-04-2010, 11:15 AM
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There is supposed to be a slightly bigger "gap" in the front than the back.
That is how the car is designed.
Old 03-06-2010, 10:18 AM
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put some 20s on the front, problem solved ...
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