Damping Adjustments?
05-12-2011, 10:35 AM
#41
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MY350Z.COM
MY350Z.COM
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NT01 , my bets are Spring rate needs to increase. 12 to 14k up front, but then you would probably need to send the dampers off for revalve.
05-23-2011, 08:26 AM
#45
You actually need a lot more spring, but since it appears yours is a street car I would go full stiff on the front bar first and see how that works. Also, increase front track width with spacers. It looks like you have enough room to add at least a 1/2" spacer on each front wheel.
You might also want to raise the car up a bit. If your roll centers are underground you're not getting much geometric roll resistance out of the suspension.
You might also want to raise the car up a bit. If your roll centers are underground you're not getting much geometric roll resistance out of the suspension.
I've posted the following before, time to repost it.
What spring rates to run ultimately comes down the math being right AND proving the math with actualy testing. The following give's some insight to a winning Grand-Am teams testing on the 350Z in terms of spring rates.
The following quotes comes from a interview of the owner of Unitech Racing Jackson Stewart, the crew chief for the 350Z Grand-Am team Jeff Wisener and the owner of Perfomance Nissan, Michael Cronin.
SZM: "I noticed a trend that many Z owners are putting coil-over suspension systems on their cars, but you mentioned today on the track that many people are putting too stiff a suspensin and actually making the car handle less effectively. Is that true and can you comment on that again, please?"
Stewart: "Yes, it is absolutely true. Most of the aftermarket suspensions sold for the car are way too stiff. More often then not, for actual track performance, a lot of upgrades are hurting the performance of the car."
Cronin: "The common perception is you don't want a car to sway in turns, squat during acceleration, or dive during bracking, but those are things you need to have the car do to handle correctly."
SMZ: When setting up your race cars, did you use or try any of the common aftermarket suspension kits that are avaliable?"
Stewart: We looked at then in a sense that we wanted to know what was out there, but we also had gone through a range of springs on the car and if we went siffer, we lost performace. We have a range of a few pounds we use in the rear to make it oversteer or understeer. So if we see a spring someone is running on the street that is 50 percent stiffer *, they are losing overall performance."
* His use of the 50% number is a somewhat ironic number to toss out given that 314lbs upped 50% is 471lbs and yet they went with 525lbs or +67% in the front then Unitech did the R&D for the Truechoice 350Z coilover system and that setup uses 525/425 spring rates.
Same interview makes mention of the following,....
Future parts for sale:
Moton Club Sport suspension package
To comment on the above, they switched to a Koni 2822 4-way monotube setup
IIRC the Ohlins PCV setup has a rate capacity of 611/504, that's what I remember from seeing the Carrozzeria spec page. Ironically IMO, I feel that it's real limit should be 672/448 (based on having owned the setup and having dyno'd them, and no I can't post them).
05-23-2011, 10:29 AM
#47
FYI... the above assumes springs in the stock locations. Also the Nissan Comp spring rates are 690/690 which work out to wheel rates around 475F and 447R.
As always, YMMV and the tires will tell you where to go on spring rates.
05-23-2011, 03:39 PM
#48
Is it possible that comment was made in reference to various tracks around the country that have less than ideal surfaces and really benefit from the lower spring rates. I can't imagine the Fontana Nissan and the Unitec guys running that light of a spring on some of So Cals tracks, CA Speedway Roval, WSIR, BW (Note: they run on a tire that would vastly benefit higher rates). Or maybe the rates they were talking about to were at the wheels like Beta suggested.
Last edited by Zazz93; 05-23-2011 at 03:43 PM.
