Do you take into account the effects of the change in the roll couple and other characteristics? Are there any guidelines on the point where the Z/G can get so low that the drawbacks outweigh the benefits? Has anyone done any calculations/ estimates on this? Thanks

 

if you are out to lower your car for looks than the cons do not matter


as far as lowering to gain performance , i would guess that buy reducing your center of gravity ,might help in cornering at high speed , other than that i can't see a benefit to lowering

i can think of many cons to lowering

cons>pros

 

my understanding is that as you lower the car you do have benefits but you also increase some negative handling characteristics.. and i was wondering if anyone has estimated this, and to what extent it is applicable. in particular, i am asking about the effects of changing the roll center/coupe..and accounting for it either static or otherwise

 

i guess i drive my to conservative to feel these enhanced characteristics found thru lowering

i have owned the below slammed

1987 Iroc Z slammed
1989 Mustang GT slammed
1992 Iroc Z slammed
1992 Mustang GT slammed
2006 Nissan 350z Slammed

always i find the negs outway the pos

but i will follow thread to learn what they have to say

 

Sometimes there are aerodynamic advantages to be gained by lowering a car. Cars that can benefit from this will have a "sweet spot" amount of ground clearance that will decrease drag. I'm not sure what height this is for the Z. Being a sports car, I would imagine that stock height is already pretty close to this.

 

Those kind of measurements are only really necessary on the track. I don't know if anybody can even afford the equipment to track or simulate car behavior at the limit.

I doubt you will notice any aero benefits to your car either.

 

go to the motorsports section. ask the guys in there, they'll know alot more about performance enhancing suspension changes than the guys in this section of the forum.

 

i definitely recognize benefits of lower cg, and could buy a little aero benefit too.

but im skeptical that you have to be on the track to consider these issues. i think there are some who would like to know they have a well setup car for their money, for any kind of driving.

For example, bump steer can be an issue. Also, as i understand it, if you lower your car you have to stiffen your springs because if you don't, you will end up with more body roll. so that would mean you have to stiffen your springs to break even on body roll. then if you wanted to limit body roll from stock you have to stiffen further from there. but how much are we talking about? or does this apply to the suspension on the FM platform? if it does apply, at what point would the incremental benefit of a slightly lower cg be offset by a other poor handling characteristics? (i would imagine this may depend on personal taste to an extent)

i agree that the equipment to do live testing is probably expensive.. however maybe there are ways to understand and approximate various scenarios?

 

on mine 2006 350z

hotchkis F & R sways
Megan Racing coil overs
Volk 19x9 and 19 x 10.5
245-30-19 & 265-30-19

i can't notice any benefit on the street

 

What the F are you smoking???

If the wheels don't hit the fender liners and speed bumps aren't killing you then the Z car is a screamer. Lowering the car with coilovers will still allow for adjustability at the track on the city streets.

How can this not be good, unless you don't align the front end after the mods & you are having tire feathering.

 

coilover!

personally got Stance!

 

I lowered my Z a total of 1". Some of the lowering (.4") was due to slightly shorter tires, and the other .6" came from RS-R Ti2000 springs.

Even thought the springs were very close to sotck spring rates, both the wife and I noticed a handling benefit imidiately.

The best way I can describe it is by using a crowbar analogy. Before the .6" drop the weight of the car seemed to have a longer "crowbar" with which to apply forces on the suspension in a turn. This made the Z "throw its weight around" more than after it was lowered. Lowering the Z brought that point on the imaginary crowbar lower to the ground, effectively shortening the "crowbar" and making the Z feel lighter on its feet.

The difference was not dramatic, but it was noticeable for both driver and passenger alike.

The only downside was an increase in negative camber. Total of -1.4 front and -2 for the rear.

Many would not be happy with the way those numbers would wear tires. But I autocross a lot, and the negative camber works well in turns. I go through two sets of tires a year anyway, and my autocrossing wears the outsides of the tires enough to even out the inside wear caused by DD on -2 degrees of camber.

 

Tekk, try checking if Bosch Motorsports still has their LapSim demo. That might help a little. But in all honesty, roll couple is nothing to look at on a DD and would be a waste of time and money. I guess I didn't know whether you are talking about a track setup or a daily driver

Here's another way to look at things:

http://e30m3performance.com/myths/We..._transfer2.htm

 

thanks. yes i will look for that demo. and yes i saw that link...you're saying you think the impact on the car is minimal unless you are doing 10/10ths at the track?

another question.

i have a g35. its lowered. but while the handling feels very good and stable at high speed, ive noticed bumpsteer when im turning hard over rough surfaces. any thoughts?

 

I can tell you that lowering my car by whatever (haven't checked), I have not noticed anything negative other than my Amuse exhaust getting scraped to hell once in a while. My car looks a lot better. It corners a lot better too; the cornering speeds I have noticed are a lot higher. All on a daily driving basis. These kind of improvements are enough for most drivers.

The stuff you want to know (I'm nowhere near an expert) is more oriented getting the most grip out of your tires, and attaining the balance you want at the limit. Just a quick surfing on the internet, bump steer is more of a geometry thing. If you are prepared to spend the money then do it. I have noticed a lot of bumpsteer, but it's at controllable speeds. If I was going 150 mph, I would be concerned.

 

looks nice, whats your drop?