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I am considering putting in adjustable air ride suspension from Air Lift Performance over this winter and was wondering if anyone has done this. There are 2 main goals. The main being to improve ride quality. When I did the engine swap for the LS3 it lighted the front end so much I had to cut 2 coils to lower it. If I go with an off the shelf setup for the 928, I do not think I will have enough adjustability to lower it. Also, I want to have a nice low stance and also be able to go over speed bumps when needed. The Michigan roads around here are not the best.
My main question is around the need to "settle" the suspension when you lift the car. I am not sure if the car will just stay up high when I air down the system.
That's a great question based on what you're looking to do. Unfortunately, I think your answer with a stock setup is yes, it will stay up because of the way the upper and lower control arm bushings work.
If you swap those out for Powerflex.kits and lubricate all the surfaces so they rotate more freely instead of binding and functioning as secondary springs, I think your idea will work.
I am considering putting in adjustable air ride suspension from Air Lift Performance over this winter and was wondering if anyone has done this. There are 2 main goals. The main being to improve ride quality. When I did the engine swap for the LS3 it lighted the front end so much I had to cut 2 coils...
When you cut coils you are increasing spring rate. Generally speaking, increasing spring rate will decrease ride quality. This effect will be more pronounced if you have lower weight. A better idea would have been to use a different spring with a lower spring rate to better match the reduced weight of the engine. There are not many spring choices for the 928 so you would most likely need to fashion new spring plates and use a standard spring which are usually available in 50lb/in increments. To tune it further, you may want to use shorter spring, this will effectively increase your rebound damping and that is generally associated with better ride quality. There is a relationship between spring rate and length and you may find a bit of trial and error is required to get it right if you don't have the experience to calculate a better fit. I f I was in your situation I'd start with a front spring with 50 less lbs/inch each than stock and with a 1 inch shorter free length. I've done many SB Chevy and LS swaps on non Porsche cars and I'm always surprised how little an alu LS weighs when considering the smoothness and power.
What shocks? What wheels and tires? For ride quality, generally speaking, you want 16 or 17 wheels and tires, OE Boge shocks, a GT focused quality tire with a load index around 92 to 95 (not UHP tires), and a spring to match the reduced weight of the LS swapped 928.
Many ride quality issues are helped with new bushings. Have a careful look at the main components of your font suspension and unless everything is relatively new it all may need to be replaced.
The correct ride Height for a 928 gives it a nose up disposition many think looks un-sporty but that nose-up setup is right. Have a look at early 928 press photos. One trick you can do to keep the correct ride height at the suspension and reduce the wheel gap for a better look is to use a slight taller tire (increase aspect ratio) . This would also help toward your ride quality problems. For example. A stock size for a 928 up front 225/45/R17. Using a 245/45/R17 or 225/50/R17 would net you more side wall and retain the wheel well filling look. That additional sidewall compliance will greatly improve ride quality. If you keep going with this idea you'll have have a Safari 928 and Safari / Dakars are all the rage, for now. A matching tall tire out back will also help and effectively increase your diff ratio but I don't think that's an issue with the torque of an LS3. This will also lower the RPM at cruising speed for a more relaxed ride.
Personally I don't like air ride, too complex and just seems to be the cop-out, I don't want to think too hard solution to every suspension problem. The folks at SEMA have done a good job in this regard. They'd bundle air ride with every LS if they could.
Last edited by icsamerica; 09-19-2023 at 11:42 AM.
The correct ride Height for a 928 gives it a nose up disposition many think looks un-sporty but that nose-up setup is right, go have a look at early 928 press photos. One trick you can do to keep the correct ride height at the suspension and reduce the wheel gap for a better look is to use a slight taller tire (increase aspect ratio) . This would also help toward your ride quality problems. For example. A stock size for a 928 up front 225/45/R17. Using a 245/45/R17 or 225/50/R17 would net you more side wall and retain the wheel well filling look. That additional sidewall compliance will greatly improve ride quality.
'80 auto with optioned 225/50-16 tires all round (nonadjustable front springs)
'89 auto with oversized tires, 225/55-16 and 245/50-16
Here's a picture of how the car sits right now. I know I need to fix something with the suspension. The big draw for air is that I can have it sit nice and low while driving but still raise it up to clear speed bumps or the occasional Michigan pothole. My current tire size is 225/45ZR17 in the front and 255/40ZR17 in the rear.
Here's a picture of how the car sits right now. I know I need to fix something with the suspension. The big draw for air is that I can have it sit nice and low while driving but still raise it up to clear speed bumps or the occasional Michigan pothole. My current tire size is 225/45ZR17 in the front and 255/40ZR17 in the rear.
Easy, get over "looking good" and set it to perform good...and you wont have to worry about it.
Also, looking good can crack blocks.
Wear a big ol blingy ring or something to take the car's place.
Here's a picture of how the car sits right now. I know I need to fix something with the suspension. The big draw for air is that I can have it sit nice and low while driving but still raise it up to clear speed bumps or the occasional Michigan pothole. My current tire size is 225/45ZR17 in the front and 255/40ZR17 in the rear.
Rear looks good. I like the visual look of 1-2 fingers between the top of the tire and the fender wheelwell at the front....I can't do the 4x4 front 928 look. Black car is where I like it - bronze car will be set at that same height once I redo my LCA bushings.
I use 928MS frame bash plates and the stronger Jerry Feather stainless belly pan to help protect the pan, alternator, and AC compressor, but honestly at this ride height, I've never hit the front bash plates.
I know but it can also help the car slide over something less impactful like a tire gator or similar.
....no it wont.
Tell you what, go jack up the car by that pan, report back how it works with just the _static_ weight of the car, not something moving at relative speed, with the mass of the car to shift in order to protect other equipment.
This is better than OE, it will resist deforming from human interaction..but it's a fart in the wind to road speed debris.
Probably so. The bash plates on the frame rails are the real protection pieces, but obviously leave a fsiley large gap between them so need some aim to line them up with whatever you're going to hit.
I've hit the ones on the Spyder on an raised manhole cover before and not a mark under the car except on the plates.
Probably so. The bash plates on the frame rails are the real protection pieces, but obviously leave a fsiley large gap between them so need some aim to line them up with whatever you're going to hit.
I've hit the ones on the Spyder on an raised manhole cover before and not a mark under the car except on the plates.
FWIW those protective plates could potentially cause more unseen damage
What happens when they hit a fixed object is that the force is sent right into the frame rails.
This has the effect of hitting the frame rail with a big sledge hammer and will bend your frame upwards.
The best way to avoid this is to put the car at the factory ride height make sure the motor mounts are good,
and don’t try to find the curb or parking bumper with the front end
Note engine damage can also occur, usually to the AC compressor or the alternator ,
and or their mounting points this can crack the engine girdle.
Note the frame damage can also be visible as a crack between the front and rear lower control arm anchor points along the side of the frame bolster,
this requires a patch to be welded onto the frame.
Note its prudent to inspect the frame after any impact is imparted to the front frame hold downs,
or the added on frame protectors, as frame cracking is very possible.
FWIW those protective plates could potentially cause more unseen damage
What happens when they hit a fixed object is that the force is sent right into the frame rails
This has the effect of hitting the frame rail with a big sledge hammer and will bend your frame upwards
The best way to avoid this is to put the car at the factory ride height make sure the motor mount s are good and don’t try to find the curb or parking bumper with the front end
Note engine damage can also occur usually to the AC compressor or the alternator and or their mounting points this can crack the engine girdle
I had a parts car that nailed the tie down anchors so hard, it pushed back the LCA's 3-4mm and put an 'S' bend in the front bolts for them.
09-17-2023, 10:24 AM
Air ride suspension
