Lowering Springs Making Handling Worse?
 

Hi guys,

I'm considering getting Eibach Pro-kit or Sportline lowering springs for my car. It's claimed to have a 1" and 1.4" drop, respectively, in case you didn't know.

I was wondering if getting a car lowered that low or with springs in general would have any negative impact on the handling and if it does, how else do I have to change to correct it.

I don't mind if it has no impact on handling whatsoever but I DO NOT want worse handling.

Don't get the sportline unless you're going to get upgraded shocks as well, the drop is too much for stock length shocks.

So just dropping it 1" is fine? That's what I was planning to do anyway. I wanted to get rid of some of the wheel gap and get a different-than-stock look without scraping on every little thing.

1" is fine on stock struts?

Just buy RCE Yellows. They are 250 lbs/in and perfectly matched to the OEM struts, putting them in the 65% critically damped sweet spot. RCE did their homework on a shock dyno with these and focused their efforts on handling instead of looks. A modest 20mm (.8 inches) drop and new bump stops are included. You'll notice more responsive, neutral handling with a sportier ride quality. Great for the street and track.

I'm selling mine pre-assembled with Whiteline Com-C top mounts here: http://www.ft86club.com/forums/showthread.php?t=70288

I'm not a track warrior like some of these other guys. I have gone to a few autoX's, but nothing to talk about. With that said, I have Sportlines. I am on cheap rubber (225/245) for now. I can't say that they have made handling worse. In fact I prefer my Sportlines over stock. They both have almost the same comfort levels, but the drive is a little bit flatter now. They are stiffer than stock to compensate for the change in height. If I have anything useful to say, it would be that my "factory spec" alignment is what's letting me down at the moment. It will wear your shocks out faster though. How much? No idea.

But that's just my opinion.

The car only has about 2.5" of bump travel stock, so taking up 1.5" of that with lowering means running MUCH higher spring rates, or bottoming out too much for good handling (unless where you're driving is glass smooth with no bumps).

For street driving and the odd auto x in a smooth parking lot you won't notice it, but on a less than brand new track you'll DEFINITELY notice it.

Thanks for the suggestion I'll consider these as well.

I don't mind running a higher spring rate, it can't be THAT much worse compared to stock right?

I forgot to mention that both Eibach kits come with shorter bump stops. But still, from what I have learned, going to the edges of shock travel isn't too good.

To run a 1.5" drop on stock shocks without bottoming out, you need way more spring rate than the shocks are happy with. That'll lead to a bouncy ride, and prematurely blown shocks.

Lots of people, including myself, run sportlines with no problems. It's a bit firmer than stock yes - you'll notice it most on bigger bumps like speedbumps and big potholes. Smaller bumps don't really seem much different than stock. I put better rubber on my car and had alignment done with camber bolts, so I can't how handling is affected by just adding springs, but I can tell you the car corners MUCH better than stock now. Don't let the "sky is falling" crew sway you - btw it's not 1.5" drop, and really not even the 1.4" drop Eibach claims, it's more like 1.2", not much more than the prokits etc. And I love the looks!

Exactly. The drop is perfect. Car looks and handles really well. I've pretty much driven the car at the limit around twisty roads and at autocross and haven't had issues.

I do want to install better springs/orshocks/orcoilovers for the future, but I think sportlines are just fine for now.


*UPDATE* This was two years ago. I thought I knew what I was talking about. The springs are just alright, definitely will need Koni Yellows because the ride gets really bad on OEM shocks.
I've been running my Ohlins R&T coilovers for the past year and it's night and day.

Pro Kit: More modest drop, better ride quality, and better chance your stock shocks wont blow.
Sportline: Extra .4" drop, worse ride quality, more of a chance your stock shocks will blow.

Reasons why I went Pro Kit:
- I live in NJ and DD my BRZ so snow/ice is an issue.
- I have a front lip and don't want to break it.
- I didn't want to buy new shocks at the moment. This isn't just for the fact that my stock shocks could blow with Sportlines..I care more about the ride quality.
- I drive 45 miles each way to work and have to keep camber in a stock-like spec for good tire wear.

I'm happy with the Pro Kit, it rides close to stock but definitely a bit harsher--the gf does complain at times. But it gets rid of the fender gap at a minimal sacrifice to ride quality. I will buy a set of coilovers next summer or if my stock shocks blow, whichever comes first.

Here's Pro Kit on 18"s wrapped in 225/40 tires.
https://dl.dropboxusercontent.com/u/...606_105229.jpg

You're missing my point. Will the car work fine on public roads, yes. Is the drop too much for the spring rate and shock travel to work well on a track, also yes. Look at quantitative results (lap times, corner speeds, etc) to see if it actually corners better. An inch of bump travel will be taken up by cornering forces easily, which leaves no bump travel for actual bumps. Any slight bump in a corner (again, on a track... not public roads) is going to upset the chassis in a big way.

You're way wrong if you think you haven't hit the bumpstops at all. The stock (and Eibach) bumpstops are very progressive and designed to be part of the spring rate. On stock suspension there is only like 5mm of bump travel before you touch the bumpstop, which means that with a person in the car you're already touching them. You may not have fully bottomed out, but you're most definitely engaging the bump stops every single time you drive the car.

Here's my car with swift sport springs (1" drop) mid corner in a fairly high g corner, notice how little clearance there is between my bumper and the track on the loaded side. With the tires I'm running (Dunlop ZII's), I really need more spring rate to preserve bump travel with only a 1" drop. If you're not running stick tires on a track, then it's a different story.

https://scontent-a-ord.xx.fbcdn.net/...75917611_n.jpg

[QUOTE=wparsons;1861007]You're missing my point. Will the car work fine on public roads, yes. Is the drop too much for the spring rate and shock travel to work well on a track, also yes. Look at quantitative results (lap times, corner speeds, etc) to see if it actually corners better. An inch of bump travel will be taken up by cornering forces easily, which leaves no bump travel for actual bumps. Any slight bump in a corner (again, on a track... not public roads) is going to upset the chassis in a big way.



You're way wrong if you think you haven't hit the bumpstops at all. The stock (and Eibach) bumpstops are very progressive and designed to be part of the spring rate. On stock suspension there is only like 5mm of bump travel before you touch the bumpstop, which means that with a person in the car you're already touching them. You may not have fully bottomed out, but you're most definitely engaging the bump stops every single time you drive the car.


Here's my car with swift sport springs (1" drop) mid corner in a fairly high g corner, notice how little clearance there is between my bumper and the track on the loaded side. With the tires I'm running (Dunlop ZII's), I really need more spring rate to preserve bump travel with only a 1" drop. If you're not running stick tires on a track, then it's a different story.

https://scontent-a-ord.xx.fbcdn.net/...75917611_n.jpg

No I think I do get your point, I'm just trying to dispel the myths about sportline springs, they work very well:

1) Sportlines won't 'blow' your dampers. It's possible they will shorten damper life yes, but you can probably say that about any lowering springs. As I mentioned before, real life drop between pro-kit, swift, etc and sportlines is not as big as you think.

2) You make the point, with sticky tires and stock suspension, track drivers at the limit are touching bump stops anyway. Yes if the track is rough the shorter springs will probably not comply with the tarmac as well, again this is probably true to a point with any lowering spring, sportlines will be a little worse.

3) Given a good driver who is an experienced track driver, will sportlines be worse than stock all other things equal? Maybe, probably depends a lot on the track. Again one might be able to make the same case about swifts or pro-kits.

4) Comfort level? This is a performance car, pull up your skirt! (just kidding!) The stock car is fairly stiff. Any lowering spring will be stiffer, are the sportline springs stiff? Yes. Do they bother me? Only when I hit tall speed bumps or deep potholes - in reality that bothered me on stock springs, just more so now that I am on the sportlines :) I don't scrape on anything (although I don't have a low front lip).

Lot's of myth out there - sportline springs won't 'blow' your dampers. sportline springs won't *ruin* handling (nor will any other lowering spring). Possible less than ideal in certain situations with rough roads, but nothing that really affects my driving or enjoyment of the car at all (and I live in the north where plows tear up the roads).

My point is, I spend maybe 300 hours a year in my car. If I'm LUCKY, maybe 3 of those hours will be lapping on a track this year, probably will be less than that. So that's 1% where I'd be worried about extracting the ultimate amount of performance, the other 99% of the time I'm enjoying my car on the streets. It handles brilliantly and looks fantastic with the setup I have - for the non-track-junkie (who really should be running on good coilovers tuned for this car) things like tires and a good performance alignment are a bigger concern rather than comparing swift springs (or other) to sportlines.