New NASA Class for 2012: Spec Z
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Joined: Mar 2011
Posts: 717
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From: SC
It translates the spring rates into terms that explain how much of the springs energy actually makes it to the wheel to perform work.
In the oem location's front and rear, a pretty high percetage is leveraged out. On a true coilover rear setup, the spring is almost directly connected to the wheel hub. So it almost transmits 100% to the wheel.
To calculate wheel rates you use the following motion rates
Front .688
Rear oem location .649
True coilover rear location .97
Example
Nissan Motorsports T2 springs
Front 690lbs x .688 x .688 = wheelrate 327lbs
Rear 690lbs x .649 x .649 = wheelrate 291lbs
Hope that helps
In the oem location's front and rear, a pretty high percetage is leveraged out. On a true coilover rear setup, the spring is almost directly connected to the wheel hub. So it almost transmits 100% to the wheel.
To calculate wheel rates you use the following motion rates
Front .688
Rear oem location .649
True coilover rear location .97
Example
Nissan Motorsports T2 springs
Front 690lbs x .688 x .688 = wheelrate 327lbs
Rear 690lbs x .649 x .649 = wheelrate 291lbs
Hope that helps
I am the new NASA_SE SpecZ Director 
I have a set of four 18x10 RPF1s, so that gives me two sets of rears (dry and wet). I still think the 18x9 RPF1 flies. Some wheel weights aren't published, and the wheel has to weigh 18.45# to qualify. With a wheel weight and valve stem, the "18.4#" RPF1 will easily weigh 18.45#. We are talking about .05#, 23g, or less than 1oz.
I have a set of four 18x10 RPF1s, so that gives me two sets of rears (dry and wet). I still think the 18x9 RPF1 flies. Some wheel weights aren't published, and the wheel has to weigh 18.45# to qualify. With a wheel weight and valve stem, the "18.4#" RPF1 will easily weigh 18.45#. We are talking about .05#, 23g, or less than 1oz.
I thought the 18x9 would be too light. Has anyone confirmed what weight they are going on? Published weight? Pop the wheel off when you come off track and weigh it weight? It will clear min weight because of wheel weights and all the rubber stuck up in there.
????
edit...I thought the wheel weight minimum was 18.5 lbs?
????
edit...I thought the wheel weight minimum was 18.5 lbs?
Last edited by Fixxxercask; Feb 16, 2012 at 07:15 AM.
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Joined: Jul 2007
Posts: 43
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From: Gainesville, GA
I will try find out who in NASA is doing what and where and report back on a regular basis here..same goes for any rules and technical questions.
But I don't know yet...but I hope to get a meeting together pretty soon with the NASA staff to get some more info...
But I don't know yet...but I hope to get a meeting together pretty soon with the NASA staff to get some more info...
I thought the 18x9 would be too light. Has anyone confirmed what weight they are going on? Published weight? Pop the wheel off when you come off track and weigh it weight? It will clear min weight because of wheel weights and all the rubber stuck up in there.
????
edit...I thought the wheel weight minimum was 18.5 lbs?
????
edit...I thought the wheel weight minimum was 18.5 lbs?
Has anyone ordered the parts recently? I'm told the pricing has gone up by my local dealer that I had placed the order with.
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Joined: Sep 2010
Posts: 57
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From: Baltimore, MD
I emailed Jeremy at NASA last week noting that the wheel weight restrictions would exclude the very popular 18x9 RPF1 and for them to consider lowering the limit. I have no indication if anything will be done however.
I have written something similar to Paul St. Clair at Nissan. I expressed to him that the RPF-1 wheels are very popular and a lot of people already have them.
b) No wheel permitted for competition use can weigh less than eighteen point five (18.50) pounds.
9.2 Tolerances
a) All published measurements infer a tolerance of +/- one-half (1/2) of the last specified decimal place. All rounding will be done to the nearest decimal place that is specified by the manufacture or these rules. In a case where a measurement falls exactly on the halfway mark, it must be rounded up or down in favor of the competitor. This section does not apply whenever the manufacturer specifications, or these rules, specify a tolerance.
I've been lucky enough to be around some chief engineers of some series like F1 and IRL. According to how they interpret their rules this would mean you can use a wheel that weighs no less than 18.45lbs. So you can include your wheel weights, valve stems and caps, because they all become part of the wheel. According to these guys "if it doesn't say you can't do it in the rules than have at it." Most of the race engineers that design these cars are very creative and fully understand every last word in their rule books. If someone is doing something that creates a huge advantage, either the sanctioning body bans it or everyone else copies what that car is doing also.
9.2 Tolerances
a) All published measurements infer a tolerance of +/- one-half (1/2) of the last specified decimal place. All rounding will be done to the nearest decimal place that is specified by the manufacture or these rules. In a case where a measurement falls exactly on the halfway mark, it must be rounded up or down in favor of the competitor. This section does not apply whenever the manufacturer specifications, or these rules, specify a tolerance.
I've been lucky enough to be around some chief engineers of some series like F1 and IRL. According to how they interpret their rules this would mean you can use a wheel that weighs no less than 18.45lbs. So you can include your wheel weights, valve stems and caps, because they all become part of the wheel. According to these guys "if it doesn't say you can't do it in the rules than have at it." Most of the race engineers that design these cars are very creative and fully understand every last word in their rule books. If someone is doing something that creates a huge advantage, either the sanctioning body bans it or everyone else copies what that car is doing also.
As we now know for sure, the NISMO is allowed. Has anyone actually looked at a NISMO? I bet there is very little done to it. Someone prove me wrong!
Latest pricing (!?): $3602
Spec Z shocks/springs: $3189
Shocks
• Front Left Shock Part# E6110-SZ350
• Front Right Shock Part# E6111-SZ350
• Rear Shock Part# E6210-SZ350
Springs
• Front Spring Part# 54010-SZ350
• Rear Spring Part# 55020-SZ350
Coil-Over kit
• Front/Rear Part# 5600S-SZ350
ARBs $413
Anti-Roll Bars
• Front Progress Part# 54611-SZ350
• Rear Program Part# 56230-SZ350
Wavetrac Diff: $1400 ($300 higher than previously quoted)
So - in total - they have added almost $1k to the suspension package pricing over the last week.
Agreed (w/r to the wheel weight based on the tolerances)!
I just got off the phone with Nissan have some clarifications for you guys:
Suspension kits must be purchased from Nissan. They will be stamped/marked in some fashion. Despite the KW part number that was on our shipping, they are not standard as they appear - the spring rates are 800/600 as the kits are assembled specifically for Spec Z. The shock valving was left up to KW to assure they are appropriate to the spring rates so those may not be standard either. Bottom line is - get the kit from Nissan directly.
Pricing I was told is $2599 for the Shocks/Springs. $185 for each swaybar.
That's $2969 total for the entire suspension kit.
Brian
Suspension kits must be purchased from Nissan. They will be stamped/marked in some fashion. Despite the KW part number that was on our shipping, they are not standard as they appear - the spring rates are 800/600 as the kits are assembled specifically for Spec Z. The shock valving was left up to KW to assure they are appropriate to the spring rates so those may not be standard either. Bottom line is - get the kit from Nissan directly.
Pricing I was told is $2599 for the Shocks/Springs. $185 for each swaybar.
That's $2969 total for the entire suspension kit.
Brian
Spec Z shocks/springs: $3189
Shocks
• Front Left Shock Part# E6110-SZ350
• Front Right Shock Part# E6111-SZ350
• Rear Shock Part# E6210-SZ350
Springs
• Front Spring Part# 54010-SZ350
• Rear Spring Part# 55020-SZ350
Coil-Over kit
• Front/Rear Part# 5600S-SZ350
ARBs $413
Anti-Roll Bars
• Front Progress Part# 54611-SZ350
• Rear Program Part# 56230-SZ350
Wavetrac Diff: $1400 ($300 higher than previously quoted)
So - in total - they have added almost $1k to the suspension package pricing over the last week.
b) No wheel permitted for competition use can weigh less than eighteen point five (18.50) pounds.
9.2 Tolerances
a) All published measurements infer a tolerance of +/- one-half (1/2) of the last specified decimal place. All rounding will be done to the nearest decimal place that is specified by the manufacture or these rules. In a case where a measurement falls exactly on the halfway mark, it must be rounded up or down in favor of the competitor. This section does not apply whenever the manufacturer specifications, or these rules, specify a tolerance.
I've been lucky enough to be around some chief engineers of some series like F1 and IRL. According to how they interpret their rules this would mean you can use a wheel that weighs no less than 18.45lbs. So you can include your wheel weights, valve stems and caps, because they all become part of the wheel. According to these guys "if it doesn't say you can't do it in the rules than have at it." Most of the race engineers that design these cars are very creative and fully understand every last word in their rule books. If someone is doing something that creates a huge advantage, either the sanctioning body bans it or everyone else copies what that car is doing also.
9.2 Tolerances
a) All published measurements infer a tolerance of +/- one-half (1/2) of the last specified decimal place. All rounding will be done to the nearest decimal place that is specified by the manufacture or these rules. In a case where a measurement falls exactly on the halfway mark, it must be rounded up or down in favor of the competitor. This section does not apply whenever the manufacturer specifications, or these rules, specify a tolerance.
I've been lucky enough to be around some chief engineers of some series like F1 and IRL. According to how they interpret their rules this would mean you can use a wheel that weighs no less than 18.45lbs. So you can include your wheel weights, valve stems and caps, because they all become part of the wheel. According to these guys "if it doesn't say you can't do it in the rules than have at it." Most of the race engineers that design these cars are very creative and fully understand every last word in their rule books. If someone is doing something that creates a huge advantage, either the sanctioning body bans it or everyone else copies what that car is doing also.