KingBaby

iTrader: (3)

Negative megatron, I haven't reach the level of Garage Scientist yet...just the inner fender has been trimmed away

terrasmak

iTrader: (8)

The geometry of the arms will be way out of wack

kilogram

iTrader: (1)

Pretty much. Loss of travel isn't nearly as bad as putting the arms in the portion of their travel where they gain significantly more camber than the degree to which the car is rolling. Watch a lowered 2g dsm on the highway once and see how much camber the wheels gain even on small bounces... This is bad for cornering, but it also castrates the car under acceleration and braking since it's trying to generate force using only the inside edges of the tires.

Has anyone on here mapped the pickup points and run the numbers through an analysis program like susprog3d or the like? Seems to me it would be useful to know what is actually happening when we lower the car. We did it with the MR2 suspension (granted, it's a much simpler suspension) and found not only the point of diminishing returns on lowering, but also found a few minor tweaks that improved the stock setup. I'll have to talk to the FSAE guys at school and see if they have any of the higher level suspension programs like Milliken..

350Zdj

iTrader: (3)

I have not seen any in-depth reviews/discussions or positive reports on here regarding the Megan Roll Center Adjusters.

My car is lowered like 1.2" and adjustable camber/toe kits all around.

I am wondering if this would help us with the lowered ride height

http://www.meganracing.com/product.a...d=850&catid=26

kilogram

iTrader: (1)

The problem I've seen with RCAs is that they rarely correct the roll center without butchering bump steer. If you move the pivot point of the lower arm, you need to move the pivot of the toe arms to match or you start inducing weird bump steer characteristics. I wouldn't put them on the car unless you could predict exactly what they'll do.

On that site, Megan also describes roll center correction for macpherson strut suspension. You can't "correct" the roll center on a-arm suspension just by moving the lca outer pivot. It will MOVE the roll center, sure, but it also changes the length of the virtual swingarm which has serious effect on the camber curve. The reason RCAs are so effective on a mac strut suspension is because the strut is effectively the upper control arm**. Moving the single pivot point can put the roll center back to where it was before the car was lowered. It still screws up the bump steer curve, and that needs to be addressed before it's an effective "correction."

**That's actually the difference between "shocks" and "struts-" a strut actually controls the motion of the knuckle. The Z uses shocks, not struts- even on the front. I don't know how many times I've read the term used as if it were interchangeable when it's not. Struts are not just coil-over shocks, they act to define the motion of the hub.

gotama

Hey all, I hope im posting in the right thread. Basically I want to pick the right suspension for my FI setup which will be done next year. First I will be running about 400-450 whp. For this power band (correct me if im wrong) I guess this should not have a major impact on the car's handling/cornering 3rd gear onwards.

However the following year I will do a full engine build and will be running 600whp. Here i need to do some changes with my suspension, brakes and tyres.

With regards to suspension what suspension mods would you guys reccomend ? By the way my Z will not be lowered (standard chassis clearance).

Cheers

MicVelo

The first thing one needs to do to get any real advice on this is to:

DEFINE your driving habits, how you drive and where.

Secondly, be honest about your skills. Handling 500+ ponies isn't just how fast you can catch the wheel. It doesn't matter if you have 287bhp or 600bhp and a suspension system if ya can't handle it. (NOT suggesting anything about your skills, just a necessary preach.)

I would say "driving school" but people make fun of me. Heh heh.

Once that's all done, you can start making choices about hardware.

The mandatories:

1. Good tires. Light wheels optional.

2. Good alignment. (Between each step... pays to get one of those "lifetime alignments" at a good shop.)

3. Anti-sway bars - preferably adjustable to match your venue of choice, abilities, and a way to tune your chassis

That's it for mandatory stuff.

The optionals - depending on need:

4. Good shocks - - If your originals or whatever you already have need replacing, go for new ones. If you track occasionally, consider adjustables, e.g. Koni Sport ("Yellows") OR...

...If you are a serious track junkie then consider a good set of coilovers for the full adjustability of height, jounce, rebound - and be ready to learn how to (and/or invest in) corner balance/weight jacking. Bilstein, Stance, KW, etc... your choice.

5. Adjustable alignment components - mandatory if you are that serious track junkie, above - but mostly for specific alignment tuning to suit a track, racing wheels/tires, or just to save tires on the street. SPL, SPC, Kinetix, to name a few.

6. Springs - if you have exhausted the capabilities of your stock set-up (and don't go with coilovers) then MAYBE springs depending on your need for eventual lowering (or not) and increasing roll stiffness to keep your spoiler off the ground. Haha.... but more for chassis tuning.... and unless you buy a set of Bilsteins (best all around shock) which are non-adjustable, you'll definitely thank me about getting adjustable shocks to tune for the springs, wheel and other unsprung weight, etc.

Did I mention "good alignment"? (I know I did.) But, this is CRITICAL for ANY suspension set up to work properly. And necessary between EACH step. Seems trivial but there is NO BETTER WAY to maximize whatever you're using.

That's it. Nutshell.

Mic

PS You'll note, I said NOTHING about the suspension's relationship to horsepower. It's not about that, it's about getting the most out of the car whether it's stock or pumped full of positive air pressure.

gotama

thx for awesome info. First of all I am a newbie when it comes to z car mods as ya probably noticed should have said this earlier :P Mainly I drive in the street and very rarely some 1/4 mile drags. Sadly in my Country (Malta) we have no track. Would be great to tune the car for track driving.


So basically in my case (for street faster cornering) apart from the mandatory things from the points mentioned above, how else can I do improve grip & handling ?


Would wider tyres help rear wheel grip on low gears & would they help with speeding faster through corners ?
if yes, what is the maximum width I can go for (front & rear) without having fender rubbing issues ? (on standard stock suspension). 19's (profile 30)

Cheers

terrasmak

iTrader: (8)

Stock suspension would probably fine for your needs. Cruise over to the wheel and tire section for your wheel and tire needs. A 305/30-19 on a 19x11 will easily work with a roll.

gotama

cheers

gotama

by the way what is a roll ?


thx

travlee

iTrader: (8)

gotama

awsome. thx

travlee

iTrader: (8)

dont think you will be happy with s-techs, i had them and dumped them within a year.

Do you mean in general, or in combo with the Tokico? I can’t go that low where I live, crappy streets. In fact, I just had the bottom of my car tore up by the rollers at the state inspections, wheel to wheel under the doors, and they said they wouldn’t pay! Aside from that, on my spirited drives so far, together with the WL sways, it feels pretty incredible. You think the above springs are better?

MicVelo

Sorry, comments above supposedly by Travlee are actually from Wet feet. (I fat fingered the move. My bad.)

Wet feet was asking about why Trav said the S-Tech were "no good"...

Wet feet

Thanks MicVelo!

MicVelo

NP.

I'm curious as to why Trav said that too. Most everyone I see that comments on the S-Techs seem to be positive about them. H-Techs maybe not so much but S-Techs...

Wet feet

Yeah, after reading that I’ve literally spent the last 2 hours drinking coffee and reading up on springs/suspension all over again!
My limited experience with the Tein so far has been positive. Usually with the wife in the car I can’t take corners/curves as aggressively as I’d like, but last week we took a very spirited drive up a curvy, scenic mountain road. The car felt great, well planted, predictable, fun as heck! So now I’m kind of interested in getting upgraded shocks just to see what the next level feels like.

If those Tokico don’t sell separately I’ll probably just get the Bilstein/Koni shocks, though I did see a set of PSS10 in the FS thread from a couple months ago 🤔

travlee

iTrader: (8)

I didnt like the stance or ride, now i will say i had them on stock shocks. I put on eibach pro kit an was happy all around, then i put on the dspecs and was in heaven.

just wasnt my liking, you may love them though

Wet feet

Understood. And I am on stock shocks too, but only 18k miles, so that might help. Plus the sways. I’m sure it can be improved upon. Certainly I believe/feel the Tein are an improvement over stock suspension. If by stance you mean lower, I would love lower, but just can’t. I wish there were a way to use "economical" air bags (not the full on air suspension) to raise the car temporarily over speed bumps, steep parking entrances etc, then I’d go lower. Love the way a reasonably lowered Z looks.

Wow, just looked at you’re profile, awesome Porsche! Dream car. I had a white 1972 914 if you know what those are, was a blast to drive. Nothing like that beast you have though. I was so close to getting an older Porsche before the Z, but I decided that ultimately the care/maintenance would be easier for the Z, here in CR.