It's about time, gutting the Nismo suspension.

Spooler

Any reputable companies you can recommend in case I want to upgrade?

MaysEffect

Kind of hard to make a generalized answer without knowing price and usage.

But i don't think you can go wrong with most of the companies in the 1500-3000$ range, certainly if it comes with a good spring setup. I personally dont think any kit is worth over 4k for this chassis suspension design unless you are going 4-way adjustable with adjustable blow-off. And TBH, thats not necessary for the street on normal tires.

Spooler

I am not very happy at speed on a bumpy rd. The car get's unstable/loose. The Nismo suspension did an excellent job in the triple digits. I am continuing to up the damper settings. I need to get ahold of the rear. I will do that this weekend. I am going up 1 more click in the front and 2 clicks in the rear. 18 clicks front and 17 clicks rear. It appears I need more spring front and rear. CRAP!!! I am thinking I may be upgrading again. We shall see. I will need an expert suspension guy to help get the feel I want, if it is possible.

Hotrodz

I got personal driving instruction from Steve Doherty, one of the first winners of the Nissan Challenge and IMSA race car drive for Doran Racing and after hitting the bump stop on different parts ot the track he suggested I increase my rear spring rate and get rid of my rear sway bar. I asked him about increasing the damper stiffness and he it's fine you need more spring. So I happen to have 11k spring set and will change the 10k out and remove the sway bar as recommended.

Sent from my SM-N910P using Tapatalk

__________________
Fast Intentions TT Installed and Tuned by Seb at SpecialtyZ 610whp 560tq:|Fast Intentions 3" TT-TDX|SpecialtyZ/Fast Intentions 72 Row Oil Cooler|SZ 6 Puck Clutch & Flywheel|3GsCustoms|Z1|Wavetrac|Hotchkis|Whiteline |Blitz|Fortune Auto 500|Fujimura|SPL|H&R|TK|TWM|RPM Rollbar|Sparco|Next Level Performance|TrackSpec|AeroFlow Dynamics|Pioneer|

Jhill

This sounds a bit odd and forgive if I've missed something but I went back a couple pages to try and catch up. If the car is loose/skippy on bumpy roads that would imply your too stiff and now deflecting off of stuff rather than absorbing it. If your trying to achieve a zero roll ride in high speed turn and at the same time eat bumpy roads up then I would say don't waste your money "upgrading" again because no suspension will achieve that otherwise every race car would just be a rally car because why bother making a rally car and a road course car when the rally car could just to it all just as well.

If you want the traction over bumpy surfaces then really a more progressive setup is desired but then you lose turn in response etc.. but that is truly the best way to get bump compliance without blowing through travel and keeping mid travel support which is why it's popular in off road applications.

Spooler

Yeap, I agree. The thing is you can only go up around 1Kg/mm on spring rates before you need a re-valve. I can't get 13Kg/mm Swift springs in the 10" length. I can only get 14kg/mm. Increasing the damper stiffness just masks the issue. This is an issue. I guess I will have to figure this out.

Spooler

Maybe I am not describing it correctly. Let me see if I can put it a different way. The dampers are doing too much work trying to control the compression.

Jhill

Well this is where I'm confused. You say it's unstable on a bumpy road but then use hotrodz track bottoming as an example which I'll bets it's safe to say isn't a bumpy road. So hitting bump stop repeatedly is not really a good thing so you have three options a stiffer linear spring for more support, a firmer high speed compression damping, or a progressive setup. Setting a stiffer linear spring will give more support and not bottom at the cost of a harsher choppy ride over bumpy surfaces (why I said I think you going the wrong way), a former high speed compression will ride the same over low speed shaft movement but be firmer on high speed impact (and can feel spikey), or a progressive setup that keeps the same small bump low speed traction but resist bottom out in a smoother motion than a firmer high speed compression, usually more ideal for off-road and not as great for smooth track

MaysEffect

I agree with Jhill. Your tuning parameters is amplifying your problem. You previously stated several reasons led you to increasing damper stiffness. If the dampers are doing too much work and you increase the rate, i don't see how this is going to improve anything. You'll be increasing heat build up and making the rebound duration longer. This would lead to increase roll and sag in the rear which would initially feel unstable. Then after increased heat it will stiffen up and increase understeer.

Is it your opinion that if you remove damper stiffness that the car bounces more?

Is the car sagging more over bumps now with increased damper stiffness? Also are you experience bumpiness or bounciness?

The difference being bumpiness results in faster and harder body movement (less than 1hz) or bounce which is more of a longer wobble and roll?

What happens when you brake hard from say 80mph and then quickly slip off the brakes around 40-50mph? Does it snap back or slowly return with a bit of lag? Also at what speed do you feel bumps are the hardest? Greater than 70mph or below? During acceleration or cruising or braking?

MaysEffect

Another question about the Aragosta's. Did they come with a dyno sheet and manual about the design? The lack of information online behind these kits is a bit discerning given the price.

Jhill

I should also mention there is no way to adjust high speed compression externally for most of our dampers (your arrogostas included) and most don't really have a low speed compression either (it is much more a rebound adjuster than a compression adjuster). Another trick that can maybe be done is IFP chamber volume (using less volume makes the ifp chamber act as a secondary air spring), not the most ideal though as I believe it can have a negative effect on overall damper performance and not as common as it once was.

Spooler

That is a noop.

Spooler

Let's just say both of you do not understand what I am trying to say. I can't tell you exactly what I am trying to do and why because of forum rules. I can say that the factory Nismo suspension is 10 times better at speed. Yes, I want the hard to achieve, but I am willing to work for it.

Spooler

Guys, this thread is about my suspension tuning process and the learning that goes with it. I have re-read some of the post above and I have to question the reason for some of the responses and the quality of them. There is not doubt you totally missed what I was trying to say and that's OK. Let's just leave it at that.

MaysEffect

100% lost me now. I'm not privy to the forum rules that won't allow you to explain the correct problem, i'm sure you guys know better than me. I never came across such a rule in any other forum though...

In response to your pm. I believe you are dealing with the typical problems of a single adjustable damper. If you were to "revalve" these dampers, you would probably want to go with tighter compression shim stacks, and possibly leave the rebound stacks alone. This should allow you to run at lower adjustment levels without restricting the rebound flow.