Where to buy complete suspension kits w/ shocks, bushings, etc.

brandonvalentin · 01-10-2012, 07:55 PM

So the car must have heard me open my big fat mouth last week Re: suspension upgrades because today I blew the driver's side front shock absorber on one of our local excellently maintained roads. Fun times.

The car has had a mismatched set on it for a while with Koni yellows w/ OEM torsion bars in the rear and Bilstein HD inserts w/ OEM springs up front. I'd like to replace both at some point, but obviously the fronts just became a lot more important.

I'm looking for a recommendation on a place to buy a good pair of front coil-overs w/ all the front suspension parts as a kit (i.e. new control arm bushings, ball joints, tie rods & ends, sway bar bushings). Our host doesn't offer such a complete kit, but I was hoping to find someone who does and would put together some kind of discount for buying everything at once. Does such a vendor exist? Is anyone at Pelican listening and would they consider hooking me up with a package deal?

Thanks,
Brandon

ernie9944 · ernie9944's Garage

^^First try our host here on Pelican "New parts Catalog" if he doesn't sell suspension parts as a kit & you want to go into Koni try Paragon Products - Porsche Parts & Accessories - Koni, Pagid, K&N, Bilstein, Racers Edge, Weltmeister, Porsche suspension, porsche brakes, 911 parts, 944 parts, 968 parts, 914 parts, 930 parts, boxster parts, cayman parts, 968, cayenne

brandonvalentin · 01-10-2012, 09:35 PM

I'm actually looking at the Koni Cup Kit from Paragon now. This seems like a decent, affordable solution to upgrade the suspension all the way around, leaving me options to play with spring rates, add camber/caster plates, upgrade sway bars, etc later as I learn more about my suspension preferences on the car. Does anybody run this kit and can anybody recommend good spring rates for a streetable car that will eventually see the occasional autocross or track day?

Thanks,
Brandon

brandonvalentin · 01-10-2012, 10:20 PM

I would also love to find someone selling a similar kit w/ tender springs included for a dual spring rate. The roads around here can get kind of rough and I think the tender spring setup isn't a bad idea.

brandonvalentin · 01-12-2012, 04:22 PM

For anyone curious, after a bunch of research, I decided to spring for Paragon's 1 Koni Cup kit. I'm going to do a rear torsion bar delete, and a spring rate of 250 all the way around. 250 sounded like a decent compromise for me on a mostly street driven car. I'll also be doing bushings and ball joints while I'm in there. Was able to get to the bushings, etc from our host, but I just couldn't afford their prices on suspension upgrades. I'll be sure to post photos / a build thread for anyone curious when I get in there. Parts should be here next week.

9FF · 04:44 PM

250 is a little soft for the rear, you should look at around a 350 rear with a 250 front or you will totally unbalance the car. Also, check the shock valving on those Cup rears. They were designed to work with the torsion bars so the spring rate was very low and the valving in the shocks might not work as well with bigger spring rates.

brandonvalentin · 01-12-2012, 05:02 PM

Quote:

Originally Posted by 9FF

250 is a little soft for the rear, you should look at around a 350 rear with a 250 front or you will totally unbalance the car. Also, check the shock valving on those Cup rears. They were designed to work with the torsion bars so the spring rate was very low and the valving in the shocks might not work as well with bigger spring rates.

If what you say is true, leaving the 23.5mm torsion bars in place should result in about 375 rear with a 250# spring, but it doesn't match up with my research. Most of the recommended street setups I've uncovered in my research are pretty even front to rear. What makes you prefer the heavier spring rate in the rear?

9FF · 01-12-2012, 05:24 PM

They are even on "effective rate" you are talking "spring rate". You say you want to run 250 springs f&r without torsion bars, that will give you an effective rate of approximately 230 front and 163 rear and a very unbalanced car.

On the Cup suspension that coilover was just a helper spring at a rate of about 100# that increased the effective rate of the rear suspension by about 65#.

Search for "spring rate v. effective rate" and you will get all the info you need.

9FF · 01-12-2012, 05:31 PM

...this might help you: Paragon Products - Porsche Parts & Accessories - Koni, Pagid, K&N, Bilstein, Racers Edge, Weltmeister, Porsche suspension, porsche brakes, 911 parts, 944 parts, 968 parts, 914 parts, 930 parts, boxster parts, cayman parts, 968, cayenne

Your assumption is wrong: a 23.5 torsion bar and a 250# spring will not give you 375# but 262#.

brandonvalentin · 01-12-2012, 06:09 PM

Quote:

Originally Posted by 9FF

...this might help you: Paragon Products - Porsche Parts & Accessories - Koni, Pagid, K&N, Bilstein, Racers Edge, Weltmeister, Porsche suspension, porsche brakes, 911 parts, 944 parts, 968 parts, 914 parts, 930 parts, boxster parts, cayman parts, 968, cayenne

Your assumption is wrong: a 23.5 torsion bar and a 250# spring will not give you 375# but 262#.

Thank you, it helps to know where you're coming from. So what you're saying is that a rear coilover spring is only 56% effective at the rear wheel? Does anybody know if that's true for coilover springs on their own, or only in combination with t-bars? Is there a different effectiveness coefficient for the springs on their own? Using that number, in order to keep the car balanced at 250# up front I'd need a 450# spring in the rear, which seems high to me.

Thanks,
Brandon

9FF · 07:00 PM

Brandon, you really need to think about the whole system as a whole rather than throwing spring rates around. Sway bars, tire size damper valving also play an important part in the overall driveabity of the car. Also, camber plates, solid bushes and spherical bearings in the top mount of your rear coilover might not help you one bit on the roads you describe and will transfer a lot of noise into the cabin.

My daily driver on smooth FL roads handles very well with 250f 350r and 968 M030 sways, coilovers all round with Konis and stock Euro right height. However, I do get a lot of noise/vibration transfer into the cabin from the upper shock spherical rear mount. I use stock top mounts at the front so no increase in noise there.

If I was on any other roads I would look at 200f 300r and would probably stay away from coilovers at the rear and get the rates I want there from a torsion bar change and adjust the handling aspect I want with sways and tire sizes. I also think that the original Boge/Sachs shocks give a better and smoother street driving experience, I find Koni valving a little harsh on the lower >300 spring rates and have mine set full-soft.

My set-up on the dd is from Ground Control, my track car uses KW Variant and is a different story altogether. FYI here are some (bad iPhone) pics of mine:

Front:

Rear:

brandonvalentin · 01-12-2012, 07:24 PM

I think this is starting to get through my thick skull thanks to a very helpful thread over at Rennlist and this post in particular from Brian Broderick that explains the trig that goes into the effective rate calculations.

Here's where I'm at:

Front motion rate on our cars average around .94. Square that to get the multiplier for the front effective spring rate of .88, meaning a 250# spring up front will equate to around 220# wheel (effective) rate (250*.88=220).

The rear motion rate averages around .65 which squared comes to .42 for the rear effective spring rate multiplier. If I want the car to be balanced in the rear at a 220# front wheel rate, I need to work backwards from there.

If I keep my 23.5mm torsion bar, I can subtract it's 126# effective rate from 220, to leave me with 94# to make up for with a coilover spring. Because the multipler for that is .42, that means I need a 225# rear coilover spring to make up the 94# difference at the wheel(94/.42=223.8).

If I want to delete my 23.5mm torsion bar, I need a 525# rear coilover spring to maintain balance (220/.42=523.8).

As my order with Paragon currently stands (250/250) if I keep the rear torsion bar I would be looking at 220F/231R at a ratio of 1.05 back-to-front. That's pretty balanced, but would be almost exactly 1 if I drop the rear spring rate to 225# (not too late to change my Paragon order).

My other option is to change my Paragon order to a 525# rear spring. I will then of course want to double-check with Paragon on the valving for that rear 30-series Koni.

Because the latter doesn't cost me anything more, I think that's what I will be doing. I like the idea of never having to reindex the torsion bar and it'll make it easier if I ever turn the car into a track car and want to be able to easily swap spring rates.

brandonvalentin · 01-12-2012, 07:36 PM

Quote:

Originally Posted by 9FF

Brandon, you really need to think about the whole system as a whole rather than throwing spring rates around. Sway bars, tire size damper valving also play an important part in the overall driveabity of the car. Also, camber plates, solid bushes and spherical bearings in the top mount of your rear coilover might not help you one bit on the roads you describe and will transfer a lot of noise into the cabin.

Thanks for your help here, and for making me think about this all a little harder.

I am thinking of the system as a whole, and I'm not going to monoballs all over or anything crazy like that due to NVH concerns. I'm going with the Weltmeister polygraphite bushings everywhere they were available and OEM rubber where they weren't (just the sway bar bushings). The only reason I didn't go with rubber all the way around is I wanted them to last a little bit longer. I will be upgrading the front shock mounts to the KLA monoballs but only because the original mounts are in pretty bad shape and the KLAs are actually considerably cheaper than new OEM mounts. I'm not adding in a camber plate or anything. I plan to run close to stock ride height with stock 15" phonies and Goodyear Eagle GT V tires for now (in Tennessee we have more than our fair share of wet weather, so I've gotta have decent traction in the wet on a DD).

I'm keeping the factory sways for now: 23x3.5mm tubular up front, 14mm rear (with the early mounting style). I'll learn a little bit more about the handling with a fresh suspension on the car before deciding whether any changes need to be made there. I also have a KLA strut brace I'm going to put on the refreshed car that I hadn't bothered with yet because the suspension on it had been in such questionable shape.

My goal here is a fun streetable ride that I can dial in for an autocross or DE (oh, and also my goal is to have a refreshed suspension system that's reliable, and it's been in questionable shape for some time). To that end, I may keep the Konis full soft most of the time, but if I know I have a track day coming up I may dial them up. 220 effective at all 4 corners seems like a reasonable upgrade from the stock ride without going crazy. I'm basically keeping the car as close to factory as possible, with newer, nicer components and a slightly stiffer spring rate at all 4 corners and leaving myself the option to easily upgrade spring rates later on if I get more serious about the track.

Thanks for all your help,

Brandon

9FF · 01-12-2012, 07:53 PM

Your getting there! I would still keep the rear torsion bars in there and go with a lower spring rate in your helper. You only have to reindex the bars once for your desired ride height and then that's it for a street car, you never have to touch it again.

I would stick to stock Euro ride height which I think is about 1in lower than US. Just make sure your front control arms are parallel to the ground and if there any rake, that the back is higher (1/4-1/2) inch higher than the front, but level is good.

You don't need to match the spring effective exactly right front to rear, just close enough. You can dial in the handling to your preference once you drive it a while on your new suspension using bigger/smaller sways and tire widths. It's a process and everyone will like things a little differently.

Finally, if you do remove the torsion bars make sure you remove the rubber "doughnuts" on the spring plates and fit something like Delrin. You will also need a good alignment after everything is fitted. Lowering will push your tires into positive camber territory and you don't want that. GL

Here's some other reading: Suspension

brandonvalentin · 01-12-2012, 08:04 PM

Quote:

Originally Posted by 9FF

Your getting there! I would still keep the rear torsion bars in there and go with a lower spring rate in your helper. You only have to reindex the bars once for your desired ride height and then that's it for a street car, you never have to touch it again.

Any particular reason for this? Concerns about the strength of the shock mounts? FWIW the Paragon kit does come with the Racer's Edge lower shock mount. I guess the attraction for me is being able to lower the ride on a track day but keep it stock on the street and not carrying the extra weight around if I don't have to.

Quote:

Originally Posted by 9FF

I would stick to stock Euro ride height which I think is about 1in lower than US. Just make sure your front control arms are parallel to the ground and if there any rake, that the back is higher (1/4-1/2) inch higher than the front, but level is good.

That's what I was going to go for and I was going to have the local Porsche shop check the height while it's on the alignment rack and help me dial it in.

Quote:

Originally Posted by 9FF

You don't need to match the spring effective exactly right front to rear, just close enough. You can dial in the handling to your preference once you drive it a while on your new suspension using bigger/smaller sways and tire widths. It's a process and everyone will like things a little differently.

Ain't that the truth. I'm sure for the first six months I'm just going to be thrilled to have something decent on there at all. =)

[QUOTE=9FF;6490550]Finally, if you do remove the torsion bars make sure you remove the rubber "doughnuts" on the spring plates and fit something like Delrin.[\QUOTE]

I've got the polygraphite ones coming for the spring plates. Should I switch to Delrin then?

Quote:

Originally Posted by 9FF

You will also need a good alignment after everything is fitted. Lowering will push your tires into positive camber territory and you don't want that. GL

Yeah the plan is to take it to the local Porsche shop w/ new rubber, have that installed and balanced and then a full 4 wheel alignment done all at once. No sense in wearing new rubber funny.

Quote:

Originally Posted by 9FF

Here's some other reading: Suspension

Thanks again!

Trinidad at Pelican Parts · 01-12-2012, 08:20 PM

Quote:

Originally Posted by brandonvalentin

So the car must have heard me open my big fat mouth last week Re: suspension upgrades because today I blew the driver's side front shock absorber on one of our local excellently maintained roads. Fun times.

The car has had a mismatched set on it for a while with Koni yellows w/ OEM torsion bars in the rear and Bilstein HD inserts w/ OEM springs up front. I'd like to replace both at some point, but obviously the fronts just became a lot more important.

I'm looking for a recommendation on a place to buy a good pair of front coil-overs w/ all the front suspension parts as a kit (i.e. new control arm bushings, ball joints, tie rods & ends, sway bar bushings). Our host doesn't offer such a complete kit, but I was hoping to find someone who does and would put together some kind of discount for buying everything at once. Does such a vendor exist? Is anyone at Pelican listening and would they consider hooking me up with a package deal?

Thanks,
Brandon

Good Evening Brandon,

We'd love to help out a fellow enthusiast, give me a call at the office tomorrow so we can understand your needs and what your looking to get from the car exactly. If we can't get what you need we'll point you in the right direction. (310) 626-8765 Trinidad

Rasta Monsta · Rasta Monsta's Garage

Quote:

Originally Posted by brandonvalentin

As my order with Paragon currently stands (250/250) if I keep the rear torsion bar I would be looking at 220F/231R at a ratio of 1.05 back-to-front. That's pretty balanced.

No it ain't. Car pushes from the factory, that setup (adding 100# of stiffness to the front) will make it push worse. Trust me. . .buddy of mine did exactly this and his car would not turn in.

brandonvalentin · 01-12-2012, 08:33 PM

Quote:

Originally Posted by Rasta Monsta

No it ain't. Car pushes from the factory, that setup (adding 100# of stiffness to the front) will make it push worse. Trust me. . .buddy of mine did exactly this and his car would not turn in.

I'm seeing a lot of people recommend setups that come in somewhere around 1.4 back-to-front. Is that to deal with the understeer?

Rasta Monsta · Rasta Monsta's Garage

TECH FORUM General Suspension Preparation 924 944 968

brandonvalentin · 01-12-2012, 08:54 PM

I guess what I'm hearing here is that if I stay with factory setup (pretty much even at all 4 corners), but stiffer I will keep the factory understeer and possibly make it worse. If I want to loosen up the rear end I need to pick something that's more like 1.4x the front spring rate. (i.e. 9FF's 250/350). That also jives with some data gathered in this Rennlist thread.