370Z Motion Ratios

PharmDZ · 08-01-2019, 02:01 PM

Hey everyone - did a good bit of searching but couldn't find a clear answer. Has anyone calculated the motion ratios for the 370Z? From what I can see there are obviously some factors which may change it from car to car, but overall for a street car I can't see it being too far off if someone has measured it near-stock. Speaking to someone from Hyperco trying to figure out what spring rates would be right for my track/autox Z. Thanks for your help!

Andrew / PharmDZ

cv129 · 08-01-2019, 03:27 PM

This article mentions OEM Z34 motion ratio

https://www.edmunds.com/car-reviews/...alkaround.html

osbornsm · 08-01-2019, 03:27 PM

I've been a car-nut for most of my life... and i have never heard of a Motion Ratio. WHAT, exactly, is that?

SouthArk370Z · 08-01-2019, 03:30 PM

Don't know if this will help but here it is:
Measuring the Motion Ratio

cv129 · 08-01-2019, 03:39 PM

Quote:

Originally Posted by osbornsm

I've been a car-nut for most of my life... and i have never heard of a Motion Ratio. WHAT, exactly, is that?

My simple brain understanding in the form of a question...when the wheel moves up by one inch, how much does the spring and/or shock move up by?

Rusty · 08-01-2019, 05:57 PM

I gave this thread a 5 star rating.

PharmDZ · 08-01-2019, 07:20 PM

Thanks everyone for your help!

Brendan · 08-01-2019, 07:40 PM

That article is wrong. Motion ratio is about where the control arm has leverage over the spring. Where the strut attaches has nothing to do with it in a divorced setup like what is on the 370. The front is .65 and the rear is .55. This is from my independent measurements and I found it elsewhere as well.

edit: .55 rear motion ration if you are still divorced spring. if you are true type then it is in fact 1:1 (like a .98 or something if you want to get really particular)

gomer_110 · 08-01-2019, 08:03 PM

Quote:

Originally Posted by Brendan

That article is wrong. Motion ratio is about where the control arm has leverage over the spring. Where the strut attaches has nothing to do with it in a divorced setup like what is on the 370. The front is .65 and the rear is .55. This is from my independent measurements and I found it elsewhere as well.

edit: .55 rear motion ration if you are still divorced spring. if you are true type then it is in fact 1:1 (like a .98 or something if you want to get really particular)

@OP, assuming you're running the "full" suspension math the other big thing you'll need to know are the weights (corner and unsprung corner). These will most likely vary from car to car depending on what type of weight reduction methods you've done.

PharmDZ · 08-04-2019, 11:07 PM

Quote:

Originally Posted by gomer_110

@OP, assuming you're running the "full" suspension math the other big thing you'll need to know are the weights (corner and unsprung corner). These will most likely vary from car to car depending on what type of weight reduction methods you've done.

I have my corner weights from corner balancing the car, but how can I more accurately get the unsprung corner weight? What does that include anyways?

gomer_110 · 08-04-2019, 11:20 PM

iirc, the unsprung weight is everything from the chassis connection out. That would be control arms, upright, brakes, wheel, and tire.

PharmDZ · 08-05-2019, 09:43 PM

Quote:

Originally Posted by gomer_110

iirc, the unsprung weight is everything from the chassis connection out. That would be control arms, upright, brakes, wheel, and tire.

Hmmm okay. I'll have to see how to get the weights for a couple of these parts. The rotors/wheels/tires are easy. The rest I'll have to dig a bit. Thanks again Gomer.

Brendan · 08-05-2019, 10:17 PM

Quote:

Originally Posted by PharmDZ

Hmmm okay. I'll have to see how to get the weights for a couple of these parts. The rotors/wheels/tires are easy. The rest I'll have to dig a bit. Thanks again Gomer.

Take the wheel assembly off and weigh that. Take the damper and spring assembly out and weigh that. Then, use a bathroom scale to weight the unsupported suspension parts left on the car. you want to hit the scale at close to full droop to make sure most of the suspension is supported by the scale.

It won't be as accurate as weighing off the car, but we are talking a pretty minor margin of error difference.

08-01-2019, 02:01 PM	#1 (permalink)
PharmDZ Track Member Join Date: Jul 2012 Location: New Jersey Posts: 997 Drives: 11 Nissan 370Z BS M6 Rep Power: 14	370Z Motion Ratios Hey everyone - did a good bit of searching but couldn't find a clear answer. Has anyone calculated the motion ratios for the 370Z? From what I can see there are obviously some factors which may change it from car to car, but overall for a street car I can't see it being too far off if someone has measured it near-stock. Speaking to someone from Hyperco trying to figure out what spring rates would be right for my track/autox Z. Thanks for your help! Andrew / PharmDZ Rusty and Hotrodz like this.

08-01-2019, 03:27 PM	#2 (permalink)
cv129 A True Z Fanatic Join Date: Jul 2011 Location: Dallas, TX Posts: 3,222 Drives: 09 Nismo, 16 Nismo Rep Power: 163995	This article mentions OEM Z34 motion ratio https://www.edmunds.com/car-reviews/...alkaround.html Rusty and PharmDZ like this. __________________ Setrab \| RE-71 \| SPL \| JRZ \| Nismo \| ARK \| Whiteline \| RacingBrake \| CJM Oil Pan \| Ti shield

08-01-2019, 03:27 PM	#3 (permalink)
osbornsm A True Z Fanatic Join Date: Jun 2011 Location: WHAT Posts: 2,551 Drives: 2018 Camaro SS 1LE Rep Power: 424	I've been a car-nut for most of my life... and i have never heard of a Motion Ratio. WHAT, exactly, is that? Rusty likes this. __________________ 2018 Camaro SS 1LE (455hp) - 2011 Nissan 370z (333hp) - 2004 VW R32 (240hp) - 2000 Civic Si (160hp)

08-01-2019, 03:30 PM	#4 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324198	Don't know if this will help but here it is: Measuring the Motion Ratio Rusty, PharmDZ, Hotrodz and 1 others like this. __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

08-01-2019, 05:57 PM	#6 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 35,180 Drives: 2011 Nismo GM 6M Rep Power: 2684437	I gave this thread a 5 star rating. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

08-01-2019, 07:20 PM	#7 (permalink)
PharmDZ Track Member Join Date: Jul 2012 Location: New Jersey Posts: 997 Drives: 11 Nissan 370Z BS M6 Rep Power: 14	Thanks everyone for your help!

08-01-2019, 07:40 PM	#8 (permalink)
Brendan Track Member Join Date: Apr 2013 Location: Colorado Posts: 640 Drives: Poor man's Porsche Rep Power: 542	That article is wrong. Motion ratio is about where the control arm has leverage over the spring. Where the strut attaches has nothing to do with it in a divorced setup like what is on the 370. The front is .65 and the rear is .55. This is from my independent measurements and I found it elsewhere as well. edit: .55 rear motion ration if you are still divorced spring. if you are true type then it is in fact 1:1 (like a .98 or something if you want to get really particular) gomer_110, Rusty, Hotrodz and 2 others like this. Last edited by Brendan; 08-01-2019 at 07:46 PM.

08-04-2019, 11:20 PM	#11 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	iirc, the unsprung weight is everything from the chassis connection out. That would be control arms, upright, brakes, wheel, and tire. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

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