Coilover Confessional
I get a lot of questions about Coilovers and I think it’s time that we devote a thread to coilovers, so this post will be an in depth look at them, the following posts will be community forum of questions and projects.
What are coilovers?
Coilovers are defined as coils over strut design; they provide a definite advantage over your typical strut/spring combo. A typical coilover setup can provide the options that many are looking, those options include strut dampening, spring rate, ride height, and camber adjustments.
Wikipedia:
Coilover - Wikipedia, the free encyclopedia
Cool, this sounds awesome, what are our options?
Well….not a lot sadly when compared to other cars. There are two types of coilovers: Full setup or Slip over. We are unfortunately at this point in time stuck with slip-on coilovers. So we only get about half the fun: ride height, spring rate (although this would require a realignment of the vehicle), and dampening adjustments. More on what is available in a little while. The two general ideas to use coilovers are to improve handling dramatically or slam the car. Pick one. Why? Because you can’t technically slam a car and expect the car to handle at optimal performance when your LCA’s are point straight up in the air.
Well it doesn’t totally blow, I can still drop it like it is hot…Right?
Yes and no. This comes down to how much you want to spend and how creative you feel like being. When dealing with slip-on style coilovers, you are limited to what struts are available to us aftermarket wise, basically the struts you would use with regular springs. The strut options here are KYB AGX, Bilstein B6 (HD), and Koni (Koni idea: ClubGP:). These seem like good options and they are, but you cannot technically “slam” your car. Why? This comes down to using struts that match the same length as stock struts (with some negligible differences). Why is this bad? Because as we adjust the ride height lower on a slip-on style setup we lose suspension travel, meaning that every inch you drop, the less travel you have for the bumps and thus the ride starts to get really rough. A full coilover setup allow you to adjust strut height without sacrificing strut travel, here is how you adjust full coilover setups to give you an idea of how they work:
On top of the fact that full coilover setups tend to also have a shorter strut, meaning that even if you set them at the highest height, the car can typically appear to be lowered. We can do the same with slip-on coilovers, it just requires some engineering. Your option here is to shorten the whole strut length about 2” to 2.5”; but you can’t just shorten the rod (otherwise you defeat the purpose and still bottom out your strut), you would need to shorten the body too, giving you the total shortened length of 2” to 2.5”, so essentially shorten the rod and the body about 1”-1.25” each. Ideally you would want to shorten the rod less than the body just to give a little extra cushion…for the pushin’
Alright, well maybe I won’t slam the car, what do you think the best strut option is?
Well if you are being reasonable about ride height (less than 2.5” drop) and still want control and comfort, I would probably suggest running Bilsteins B6s with a reasonable spring rate (Less than 300# springs), but these will not offer any form of dampening adjustment. KYB AGX’s will give you dampening adjustment and the ability to do a little more than the Bilsteins, although I personally don’t like KYB’s, we are limited and this is what I currently run. With these you can run a variable amount of spring rates, but keep in mind the higher the spring rate the rougher the ride. And last but not least, the best option in my opinion is the Koni’s. You can either run the above setup with the Koni’s with the stock strut length or give Koni a shout and have them make you some custom strut inserts. If you go for the stock length struts you can run them like the KYB AGX’s and vary the spring rates, the more you want to drop the higher you want to ramp up the spring rate. If you go all out and have Koni make you some struts, you will want to have them shorten the strut altogether, along with this option of shortening Koni even offers the ability to have them valve for a spring rate you are choosing. (Koni North America - Racing Division) This is ultimately the best option by far since you can get the correct dampening for high spring rates and a shortened strut, it’s a win WIN!....but it comes at a price, Koni quoted me almost $1000 just to do all this work, without even buying the struts. **I contacted KYB and they said they couldn’t do it because that would than divulge their strut dimensions that are apparently a closely guarded secret**(I’m serious I have the eff’n email from these guys, another reason why KYB blows, but it is all we have).
Spring Rates…Why do you keep saying that?
Spring rates are important because this is what it takes to compress the spring, when lowering a car it is common for the spring rate to increase, especially when you begin to lose strut travel. This is really not an ideal way to do things for handling since sometimes you can exceed the struts ability to work the higher spring rate. So a 250# spring will take 250 lbs to compress it one inch and a 400# spring will take 400lbs to compress it one inch. So for handling what you will want to do is pick a spring that already works with current strut valving or have something custom made and matched to a high spring rate (kill the body roll). For slamming or dropping low, you will just have to mismatch the spring with the valving, the general idea is run 400# front springs and 350# rear springs or maybe one step higher at 425/375, but be forewarned, your ride will not be the most comfortable, but it is “livable” (depending on your definition of “livable”, if you like your car to feel like the axles are pretty much bolted to the frame, then you can do it…okay it’s not that bad, there is some give). Another heads up that when you do drop stupid low and mismatch out of optimal spring rates for a strut, you are shortening its life dramatically, you can expect the strut to only last a fraction of its life expectancy.
Alright I get it you Saab humping asshole…so where do I buy these?
Well, you can buy these all completely made for you or you can make your own
Buying:
ZZP (made by HT Motorsports, so if you want to pick your spring rate, you need to go direct to the source): **and yes, you need the rear brackets**
ZZPerformance - Coil Over Strut Package for Wbody #ZZ-COVRSRT-WB
Intense: (They don’t have the custom top mounts like HT makes)
INTENSE-Racing.com: INTENSE Coilover Pair for 97-03 W-Body
HT Motorsports (now Arraut Motorsports…I guess):
W-Body Products |
You said make your own, what does that take? Well I will include some links to various threads to give you an idea of what you can expect. I see that Arraut Motorsports now sells kits, where they sell you the springs and top mounts, which I recommend because those top mounts are worth their weight in gold, which is to say that doing the completely custom route isn’t any less impressive either.
Links:
ClubGP Message Forum troubleshooting
Grand Prixs Of North America • View topic - My homemade DIY coilovers *lots of pics*
My DIY coilover swap thread!!! Update: Got my springs in!!!
So this rear bracket…wtf is it?
The rear bracket is so you can keep your rear sway bar, you NEED TO KEEP YOUR REAR SWAY BAR. Plain and Simple.
This is what it looks like (click, cause picture is huge):
http://arrautmotorsports.com/files/2...over-G.M.1.jpg
Okay I bought the coilovers, what else do I need?
Well, these coilovers leave the strut a little exposed in my opinion, which can also shorten the strut life if debris can contaminate the oil in the strut. So I recommend getting some coilover covers, I tried a couple different options and these are the ones that I currently run and seem to work well (IIRC, I ran the one they marked Rear in the Front and vice versa):
Gearheads Online :: HRP :: HRP Coilover Covers for Evo X
Sorry, I don’t have any pictures, but it will come up a little short so it will wrap around one of the rungs of the spring but the Velcro on these things are awesome so it will hold.
I also suggest lubing the crap out of the thrust bearings since they are open to the elements, I used white lithium grease and have yet to go back in there to relube them (hehe Lube…Here is an amazon listing to a 55 gallon tub of lube for no reason (no don’t buy this…it’s a joke): Amazon.com: Passion Natural Water-Based Lubricant - 55 Gallon: Health & Personal Care
There were some sealed thrust bearings, but someone ordered them and I think they ended up finding out that they were discontinued.
I’m a 2004/2005 Grand Prix…can I do this? (and I think some 2006’s)
Yes, you just have to swap out your LCA’s to ones with the sway bar mounts built into the LCA, which looks like these (see the little tabs):
You will also have to swap out to a 97-03 style sway bar, the dorman sway bar is the best option since it is solid.
If you aren’t sure what you have for a setup, a quick look through the wheel should tell you. If you see a long skinny bar connecting up to the strut, then you need to swap it all out. Otherwise you should be good to go. GXP’s and post 2006 GP’s should not have to do any of this stuff, these coilovers should be a direct drop in.
Okay enough talk, show me some pictures of the car dropped as low as possible.
Unfortunately, I never dropped all the way. When I started with the install, I started with the rear and I dropped them setup all the way and it wasn’t going to work. See the white line on the tire, that’s how much of the tire that is covered on a drop all the way:
This is how much more I could drop the front spring (but at this point I tend to bottom out the strut with a decent bump, also notice what happens to thrust bearings when exposed to the elements):
And what that looks like on the outside:
So do you regret buying these?
Nope, I’m glad I bought them. I do wish the ride wasn’t so rough and I could get some of the adjustability like the full coilover setups. But it’s not all that bad, the car feels great and feels like it’s on rails; despite the fact that my LCA is pointing straight up in the air (the idea is to keep the LCA parallel with the ground as much as possible for optimal handling).
Another member on this forum bought coilovers and realized quickly that these do have limitation, unlike air suspension which he has now. Read up on his thread:
http://www.grandprixforums.net/baker...nce-63328.html
So I bought these Coilovers and when I jack up the car, do my ****, then lower the car back to the ground, I hear a loud bang. What is that?
Because these are slip-on coilover setups, the spring dismounts from the top mount and when you lower the car back down it “snaps” (bangs or pops) back into place, it really doesn’t hurt anything and over time it seems to slip in place easier. This is another reason to get coilover covers, they help hold the spring in place so 9 times out of 10 you don’t get the “Bang” into place effect. I also found that lowering the car slowly tends to help.
Can I daily drive these?
Sure, but be aware they are “exposed” to the elements between the strut and thrust bearing. Also if your slamming, you have to weigh the options between being able to adjust on the fly with air bags or be static and risk taking some serious damage at some point, of course if you’re riding lower on air bags going down the road, you risk not reacting fast enough debris or pot holes. So understand the risks of being low and daily driving…**** can happen.
For others who would like to post, they can talk about their experiences with coilovers or their build ups or if you have questions, ask them here!
Thanks for reading…and I apologize for grammar and spelling mistakes.
Originally Posted by deadwoodspecial
