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| iCorvette | does lowering any amount and nothing else make for a better handling Vette? | ||
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Senior Guru
 
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Or does the lowering cause weird geometry changes resulting in inferior handling.
not to mention giving up the beautiful ground clearance... |
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Posted on: 2010/11/14 22:23
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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The Stig Moderator
 
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While a lower Center of Gravity does make for better handling, it also changes the geometry some. Depends on how much lower. And yea, ground clearance comes in there especially for the street.
Lowering the car will affect the alignment too since a C4 has bump steer built into the geometry with the dimensions where the suspension attaches. And if you lower the car, it's wise to put on stiffer springs (ground clearance) and match some good shocks to them. C5's are almost worse, if you lower it too far, the handling really goes to hell. |
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Posted on: 2010/11/14 22:33
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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what is bump steer?
contrary to what some of my frienemies say, I kind of like the wide gap between the tires and the fender lip of the C4's. In my future? suspension upgrade, hence my asking, and since the suspension will be apart, the question to lower or not to lower comes to mind. If the effort to lower does not yield a better handling machine, forget about it. and I if will scrape stuff then really forget about it. I already have 32mm fronts and 26mm rears with polys, the car does not pitch or lean... and for legal speeds it's is fine, but I have the Corvette sickness like everyone else. at most it would be 1/2 inch to a 1 inch drop. |
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Posted on: 2010/11/14 23:03
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| bogus | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Grand Imperial Pooh-Bah
 
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bump steer... when the suspension is in compression, how does it effect the alignment?
Will the tire toe-in or -out when the suspension is compressed. I don't like lowering for street use, at least not on the Vette. It is already pretty low... and remember, contact patch! It is so very important to remember that if the suspension is too stiff, what does it do when it hits a rough patch? It skitters... and then you lose traction. Do I need to elaborate more?  |
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Posted on: 2010/11/14 23:19
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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The Stig Moderator
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Bump is when the suspension moves up, i.e. when you go into a left hand corner, the right side suspension moves up (and compresses the shock). Droop is when the suspension moves down.
Bump steer is the change in toe-in from static ride height. This happens because of the difference in the arcs that the upper & lower a-arms and the tie rods go thru. Since the a-arms and tie rods are different lengths and don't have symmetrical attachment points, they travel thru different arcs, this usually causes more toe-in in bump. It depends on the suspension design but usually you see more bump steer (toe-in) as you get higher & higher in the arc. Like you may see .050 from 0 (static ride height) to 1 inch of bump and quite a bit more from 1 inch bump to 2 inches. So, lowering the car may cause a bit more bump steer, again depends on the design. The only way to really know is to do the measurements and that is a lot of work. You may want to ask Jon (Spectator Racing) how much his car is lowered. Also, DRM (Doug Rippie) makes brackets for the rear that keep the bump steer to a minium. |
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Posted on: 2010/11/14 23:35
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| bogus | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Grand Imperial Pooh-Bah
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several years ago, the last generation Honda Prelude offered a package called "SH" for Superior Handling.
The option included an eletronically controlled active differential. It used a yaw sensor to direct power to the inside tire in a turn to help overcome the inherent push of a FWD car. The problem? To use it required you to really dive into a corner... after a few laps, the setup would then throw a code! Oh, good. One other feature of the option was an articulated lower control arm. This extra leverage did wonders for bump steer and other nasties that effect tire contact patch in corners. |
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Posted on: 2010/11/15 2:17
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| cuisinartvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Elite Guru
 
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Id leave it at stock height and enjoy the car
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Posted on: 2010/11/15 2:39
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| Dale1990 | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I lowered my 90 with longer bolts in the rear and trimming of the front rubber mounting pads with wedges. I wish I hadn't. The ride quality suffered, I have problems with speed bumps and the handling on poor roads is significantly worse. Some of that is probably from the poly bushings I also installed, though.
If I were to do it over again I would have just found a matched set of springs, sway bars and shocks and called it a day. |
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Posted on: 2010/11/15 14:03
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| biggrizzly | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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2011 Memorial Day Car Show Winner!
 
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How about lowering with coilovers and QA1s? Any bad side effects? I was considering doing the poly-bushing kit and lowering, but now you have me thinking about that.
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Posted on: 2010/11/15 14:09
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Don, the coilovers won't change the geometry at all but, they will let you set the ride height where you want it. And you can get progressive rate springs that will be softer on the street bumps and stiffer on the Autox yurns. Also, the individual adjustment will let you take out the left side sag that many C4's have. And, if you get serious about autox/track, you can lower the car for the events and return it to "street height" fairly easily, probably just by jacking up each corner ( I don't think you'd even have to pull the wheels). But you should have a second set of wheels with autox tires anyway. And the QA1's give you the rebound adjustment on the shocks too. But, I'd still add the DRM rear bracket. No, no bad side affects at all. |
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Posted on: 2010/11/15 14:36
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| bogus | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Grand Imperial Pooh-Bah
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I don't like rear bushings... There is an inherent preload designed into the rubber bushes. Install unforgiving poly, and you really preload the links.
I have the Banski Kit; did an install story for Corvette Enthuasist. I did the install just over a year ago and it is working brilliantly. I love the ride quality, I love the immediate response. Just awesome! It is more expensive, but it is the best way to fly. Check with Banski and see if they have a GP going on somewhere. |
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Posted on: 2010/11/15 17:30
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I decided not to lower, I like the looks both ways lowered and not, so that's not the concern. as far as the polys, you are saying keep the rubber ones, or skip straight to this? but never polys correct? VBP is having a major sale http://www.vbandp.com/C4-Corvettes/Su ... -Combo-w/Racing-ends.html how is just doing the rears and leaving the front's alone, or is going with the Delrin banski fronts and leaving the rears alone better? |
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Posted on: 2010/11/15 20:36
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| Steve40th | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Elite Guru
 
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You will scrape more once you get past 1 inch lowering. But it all depends on your roads, driveway etc etc. C4's seemed to get higher and higher throughout the years, just look at an 84 next to an 96.
The only way to truly tell if lowering does any harm or good is to run your car on a timed course. Then lower it, using the same alignment specs as before and see if the car handles better. I dont think it will make any major differences. But, the C4 Challenge cars were lowered, rather uniquely , so maybe it does help. Attach file:  BAKER%204%20CAR%20018.jpg (276.40 KB) BAKER%204%20CAR%20005.jpg (317.92 KB) |
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Posted on: 2010/11/15 20:38
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| CentralCoaster | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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FWIW I've found it to be about impossible to keep the lowering pads glued in place up front. When I have some free time, I'll give it a 3rd (or 4th?) try at regluing them.
Dale, lowering on its own should not effect ride quality as long as it's not bottoming out. I would suspect your stock rubber bushings have turned to rocks. This will really stiffen up the suspension. Also if the front wedges and shims aren't setup right the spring can contact the frame. I'm not sure if the lower CG counteracts whatever worse suspension angles it causes, but I doubt a single person on this forum is a talented enough driver to tell the difference. |
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Posted on: 2010/11/15 20:40
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| Steve40th | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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CC, I agree with the bushings being old and hard. When I put poly bushings in and ball joints, the ride became much better. And I lowered 2 inches.
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Posted on: 2010/11/15 20:45
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| CentralCoaster | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I don't understand why anyone would bother with coilovers in back. The only benefit I see is ability to run progressive rate springs. Yet most aftermarket coilovers I've seen don't have that.
The rear spring is a pure cantilever setup, so there isn't any binding like the front one. Another thing to keep in mind is when going coilover in front you're losing the front springs anti-sway ability, which according to GM engineers makes up something like 25% of the total anti-sway. I think a sway bar with adjustable end lengths would be bitchin on these cars. |
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Posted on: 2010/11/15 20:45
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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To this day GM believes in leaf springs, they are still in the ZR1 correct, so how bad can that be, that car is awesome. there is alot going for that design... |
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Posted on: 2010/11/16 1:35
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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There's nothing wrong with the leafs. But the coilovers are much easier to work with if you're going to compete. Note that the Z06X at SEMA had coilovers and the C6Rs. |
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Posted on: 2010/11/16 1:45
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| Dale1990 | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I don't want to hijack but... The front and rear control arm bushings on my car are poly - I used the whole kit from Energy Suspension sans the steering rack bushing. Sway bar bushings and endlinks are still OE rubber circa '90. I'm contemplating getting NOS replacement arms from Corvette Recycling for the front and going Banski for the rear. Shocks are new Bilsteins, too. I flat out do not like the way the car handles right now. I haven't stuck my head under the car to check out the wedges lately but I wouldn't be shocked if they became unglued, too. |
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Posted on: 2010/11/16 4:53
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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sounds like what was done to the care is classic and basic, handling oriented mods, elaborate on the "flat out don't like it", does it swerve? bottom? hop? skip? jump? dive? skid? push? tail happy? stiff? soft? twitchy? creak? rattle? squeak? moan? groan? slide? jar? fwiw, I have VBP 32mm front bars with poly and rear 26mm with poly and this transformed the car. I am surprised you went the other way first, everything but the bars... |
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Posted on: 2010/11/16 5:51
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| CentralCoaster | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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BTW dale, even the steering rack poly bushing from Energy fucked me.
The inner sleeve wasn't long enough so when I tightened the bolt down, it just clamped down on the poly. Of course over time the poly compressed a little, so it loosened up and moved with whatever slop was there between the bolt and sleeve. This made for about a few inches of play right in the center of the wheel... completely annoying. So I'm left to either pull the rack out again to shave the bushing or rack, or else just keep tightening it every 8 months until the bushing compresses enough to actually allow the bolt to clamp onto the metal sleeve like god intended. *Sigh* |
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Posted on: 2010/11/16 8:04
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| Dale1990 | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Quote:
There's quite a few things that I don't like about it. The only car I have to compare it to is an 86 w/ Z51, aftermarket shocks (can't remember the brand) and less than 60k miles. By comparison, the 90 feels very loose and seems to wallow - not unexpected for 180k miles I suppose. It doesn't respond well at all to bumps. The body seems to jump up too far (like it overreacts) then drop back quickly and settle almost immediately - very disconcerting. I could provide a better comparison when I get the 86 back on the road this weekend, hopefully. The poly squeaks but it isn't bad enough to bother me over the rest of the rattles, creaks and buzzes in the car (exhaust is rubbing on the x-brace). As to the order of mods, I had a diff seal start leaking and it dissolved the rear bushings. Since I also had a ujoint on its way out at the same time I decided to just get the kit and do the whole rear end. When I did the lowering (purely for aesthetics) it was only a few more bolts to get to the front bushings and I already had the shop press. This isn't really at the top of my fix-it list so I am not planning on working on it anytime soon. |
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Posted on: 2010/11/16 14:02
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| cuisinartvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Dale my 90 used to do the same porpoising you described, it was the shocks. Night and day diff.
They appeared Ok but in reality were shot to hell. |
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Posted on: 2010/11/16 18:17
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| Dale1990 | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I replaced these either last year or the year before if I recall. New Bilstein sport shocks. They have maybe 10k on them by now but he ride has not changed noticeably. |
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Posted on: 2010/11/16 18:39
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I understand the "while your in there" doing other stuff, "you might as well" go for the polys since it's "only" $180 bucks, mine squeaks like hell, and they are only on the bars that's another thing to consider.otoh some people boast how instantaneous the reaction to driver input is with polys and that overriding sensation negates all "minor" problem associated with the polys. |
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Posted on: 2010/11/16 18:59
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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good to know first hand; the broad statement that these things work is simply too general, It's like sleeping on a massive wet spot all night; cold and clammy. something that is performance and suppose to make your handling better makes it worse, is downright a crime. perhaps Prothane or VBP did more R and D with their products, what did ES have to say about your damages? |
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Posted on: 2010/11/16 19:04
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| CentralCoaster | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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After a few phone transfers I was able to get in touch with someone in the engineering department regarding the sleeves being too short. I explained to him my concerns and he agreed that yes, the bolt needs to clamp the inner sleeve in place for the bushing to work as intended. He offered to send me a new set of sleeves.
Then I asked him how new sleeves would make any difference if they're coming off the same assembly line as the ones I already had installed. He didn't have an answer for that. Basically unless they're willing to get a Corvette in their hands and retool the parts properly, it'll never fit right IMO. Or maybe it's GM that's tolerances are way off on production. Who knows. Either way it's not something that's high on anyone's to-do list at Energy Suspension. And unfortunately many customers installing them have no idea how the bushing is supposed to work and don't question it. |
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Posted on: 2010/11/17 6:24
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| Steve40th | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Posted in wrong thread, oops
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Posted on: 2010/11/17 6:36
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| iCorvette | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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seems to me to have that kind of product, like Haynes repair manual co. they would have a car to take apart and take specs off of and offer a product that works. instead of just saying it works and cast it in some cute color to seduce the public, oh well, no steering bushings for me.
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Posted on: 2010/11/17 9:23
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| SpectatorRacing | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Quote:
Sorry I'm late, I just got back from Japan and missed this thread. You guys covered most of it, but I can at least address Bill's question. The car is fairly low, but I have an extremely stiff suspension set-up to counteract it. It's aligned statically (obviously) and the stiff springs prevent ~85% of the roll. I'd have to check, but off the top of my head I think they're 450 lb front and 300 lb rear. (which does not translate well to a leaf spring rating...) I don't have any ride height measurements from when it was stock, but I can go measure the car as it sits if anyone needs the information. I would NOT recommend this set up on the street. I used to street drive my car with these spring rates. Once I hit a bump and snapped the rear suspension knuckle shock mount... Here is a shot of how little roll there is. These ere taken in the same corner, inside and outside shot. This is a fairly slow corner, but on camber so I'd guess about 1.2 g's. There is probably less than an inch of ride height change overall. Attach file: Turn 2.JPG (0.00 KB) |
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Posted on: 2010/11/17 19:01
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Thought I saw 650 suggested for autox on a set somewhere on a web site. Interesting, I'm running 350 front and 400 rear.....on a 950 lb car.  |
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Posted on: 2010/11/17 22:22
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| CentralCoaster | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Here's a lowered Z51 with poly bushings at maybe .9 something G's on street tires. It can't be much because there's an instructor in my passenger seat. These cars just don't lean much.
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Posted on: 2010/11/17 22:44
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| SpectatorRacing | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Nice ass
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Posted on: 2010/11/17 22:56
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| SpectatorRacing | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Here's an old one I found with some lean. It also shows off my sweet rattle can paintjob after the fire.
Attach file: C4 roll.JPG (0.00 KB) |
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Posted on: 2010/11/17 23:00
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Looks better without thet rookie plate.   |
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Posted on: 2010/11/17 23:02
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| Steve40th | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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ZO7 suspension with poly bushings, camber bar (LOL), S/T Frame, BFG KD'S, and large ZO7 sway bars about 35 mph. Also, lowered 2 inches
Attach file: SCCA 12509.jpg (117.13 KB) |
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Posted on: 2010/11/18 3:21
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| Steve40th | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Nissan GTR in same spot.
Attach file: NissanGTR.jpg (104.73 KB) |
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Posted on: 2010/11/18 3:22
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| SpectatorRacing | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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I drove that rookie plate for years. People gave me more room if they thought I would lose it and hit them when they tried to pass Plus, I was pretty proud of my orange spraypaint job! |
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Posted on: 2010/11/18 16:38
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| BillH | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Yea, coming up on one of them does make you say "Ah Crap". |
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Posted on: 2010/11/18 16:46
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| 93Moneypit | Re: does lowering any amount and nothing else make for a better handling Vette? | ||
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Guru Newb
 
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I lowered my 93 about 1 inch sanded down the front rubbers and cut the same amount off the aluminum blocks with the longer bolts in the rear.
It handles about the same as stock but it looks a hell of a lot better but I'm also using all stock suspension parts + fx3 select a ride shocks. I do have to pay attention to steep driveway's and speed bumps or ill drag my glass packs and those dam cement wheel stops they hit my front skid plate. I'm glad i only dropped it 1 inch. |
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Posted on: 2010/11/19 11:10
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