IgorT.455/406

Hey guys. I need some help in understanding these new coilover kits for third gen cars.

What is the advantage/dissadvantage of switching to front coilovers vs. stock style spring/strut separate? Will my existing third gen struts work?

I am looking at different K-member options, and there is those with and without coil overs. Not sure which would be better, the price difference is not huge, so what would be better? What would be lighter? Would I have to get coilovers in the rear as well? Good idea anyway?

What about selecting coilover spring rate. Option is from 80-1000, kind of a big range. Is it possible to run this coilover kits with "soft" springs in conjunction with the regular coil springs in the car? Thanks guys, forgive my lack of knowledge.

85TransAm406

coilover kits place the spring load directly on the strut towers, as opposed to how they are designed from the factory with the spring loads on the k-member. they do, however, eliminate the bulky factory lower a-arm, as the spring isn't directly located on it anymore. You have to use their struts as they should be adjustable.

You may have to try a few different spring rates with the coilovers, but some places will let you put them on the car and see if they're ok and send them back if they aren't right, but the techs or someone else with a coilover setup could get you in the ballpark.

IgorT.455/406

Hmm, I might stick with the stock style setup, but get a new k-member and a-arms. Still not sure, but I really don't want to stress my strut towers any more, as the body is not new these days.

85TransAm406

That's the route i'm going, as i'm going for a road race setup in my 85. I'm waiting for spohn to come out with his version, but they're taking a while. Some of the other companies, i.e. Pro-fab racing and PA racing will reinforce thier k-members for use is a street/road race car, as they are mainly designed for drag racing. I know pro-fab usually does it for free, but they have to build it when you order it.

kandied91z

try asking people who own them. spohn has been stating he'd make a set forever now.

the tubular k-members are lighter in general, the chromoly versions are that much lighter. going to coilover struts on the car will remove the springs and perches naturally with the proper a-arm/kmember upgrade. yes originally the k-members were designed for dragracing in mind as the purpose was weight reduction, suspension adjustment and more room in the engine bay for headers, turbos or any other accessory needed.

as far as their worth. no one on the internet has shown a strut tower that has broken from the weight of travel. many say they won't work for roadracing...understandable that they may fatigue over time but the extra bracing that is an option should be added for those who have a sole purpose of auto-x only. many who drag race, some who attempt 2-3' drops 2-3 times a week at the track have not complained of any problems. neither have those who work with them on the street.

advantages: less weight, more room, better adjustment and looks cool.

disadvantages: cost, tricky to setup (need to learn proper spring rates and decide dia strut housing to use) you will loose some inner wheel well area so those who want to run an exceptional wide wheel above 9.5-10" will need to consider against the idea.

out of all the versions that are available today no one has shown proof of one having problems. however a few who abuse their cars regularly have shown upper strut plates that have bent over time particularly the billet aluminum versions through the extra weight. art morrison makes upper spring perch plates for the coilover springs that help disburse the weight much more evenly that can be had for roughly $35 a piece. highly recommend getting these just as added precaution.

with that said most coilover setups come with a sleeve that slips over the strut housing. typical strut housings are 2.5" od like koni, kyb, gabriel, monroe. there are a few exceptions with models. bilstein being one which will need a larger 3" od sleeve that is hard to track down. spring rates come in various sizes and heights like described and many many companies make them. choose your brand. i prefered eibach ers over my hal versions. hal is what comes with the pa racing and art morrison setups. finding the proper spring rate is crutial as well as the right valving for the typical ride height you plan to leave it at so strut/spring choice is essential to this, more so then stock.

as far as your last question. no you do not have to run coilovers in the rear. i didn't and it worked perfect. i liked the coilovers in the front for adjustment where it was needed by my car was strictly a street/weekend warrior so i didn't care about auto-x professionally and dailing all 4 corners. this is something that is available though if that interests you, many have done it with complete success.

would i do the coilover conversion again...probably not. only because i love my airstrut which is essentially the same exact design but uses an air bag instead of coilspring. the adjustment and ride is uncomparable to the coilovers. however the cost is 2 times. the coilovers once properly adjusted rode better then stock, but nothing like air.

good luck.