Suspension/Wheels/Tires/Brakes

cornerweighing my FD - a work in progress

Thread Tools
 
Search this Thread
 
Old Nov 5, 2007 | 07:11 AM
  #1  
2MCHPWR's Avatar
Thread Starter
FD / LSX
Tenured Member 15 Years
iTrader: (2)
 
Joined: Jun 2004
Posts: 1,359
Likes: 0
From: wawayanda, NY
cornerweighing my FD - a work in progress

The new coilovers are in and I took car for a spin today and they felt insanely great. I can't believe 900 lbs springs can feel so good. Not jarring at all. The car needs an alignment but it still felt good enough to drive around. No pulling or shaking.

So I put her on the corner scales tonight to check the starting points.
Notes:
-ride height is off as you'll see, mostly in the right rear. That is because I just bolted them in from the car I got them from.
-sway bars need to be disconnected before doing any adjusting. So these numbers are skewed slightly.

Results:


I will use this page as what steps to follow on how to adjust (I posted 2 links in other thread but they are good): Understanding Corner Weights - How To - Hot Rod Magazine

This one looks good too:
Grassroots Motorsports » Understanding Corner Weights

I'll update this week with how I adjust and how it changes the weights.
Reply
Old Nov 5, 2007 | 07:37 AM
  #2  
BoostedRotary's Avatar
Junior Member
 
Joined: Mar 2007
Posts: 44
Likes: 0
From: SA
I have also recently corner weighted my track FD, I dont have my sheet with me for exact measurements but with myself and 1/2 tank of gas it weighted in at 1278 kgs with a perfect 50/50 distribution and 320,5kgs on each wheel.
Reply
Old Nov 5, 2007 | 08:40 AM
  #3  
ptrhahn's Avatar
Lives on the Forum
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (11)
 
Joined: Feb 2002
Posts: 9,282
Likes: 703
From: Arlington, VA
Where'dya get those savory JRZ's?
Reply
Old Nov 5, 2007 | 10:19 AM
  #4  
cabaynes's Avatar
Old and grumpy
Tenured Member: 20 Years
iTrader: (4)
 
Joined: Mar 2002
Posts: 2,600
Likes: 6
From: San Francisco, CA
please do update this thread.

also, which scales are you using?
Reply
Old Nov 5, 2007 | 10:24 AM
  #5  
aznpoopy's Avatar
strike up the paean
Tenured Member 20 Years
 
Joined: Aug 2003
Posts: 2,495
Likes: 2
From: fort lee, nj
Originally Posted by 2MCHPWR
The new coilovers are in and I took car for a spin today and they felt insanely great. I can't believe 900 lbs springs can feel so good. Not jarring at all. The car needs an alignment but it still felt good enough to drive around. No pulling or shaking.
congrats!

i believe it. get quality shocks and you'll have a quality ride, even with stiff *** springs

are you doing this yourself or at a shop? i've been looking for a local shop in jersey that does corner weighing
Reply
Old Nov 5, 2007 | 11:09 AM
  #6  
ptrhahn's Avatar
Lives on the Forum
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (11)
 
Joined: Feb 2002
Posts: 9,282
Likes: 703
From: Arlington, VA
Oh yeah, FYI, you probably don't really need those helper springs, the car will never see full droop condition on the road... I had the same question when I first put the GC's on.
Reply
Old Nov 5, 2007 | 11:29 AM
  #7  
2MCHPWR's Avatar
Thread Starter
FD / LSX
Tenured Member 15 Years
iTrader: (2)
 
Joined: Jun 2004
Posts: 1,359
Likes: 0
From: wawayanda, NY
anzpoopy - i'm doing it myself. i borrowed a friends long acre scales. i have heard Will DiGiovani from Precision Motorsports is very good at this (908 832 - 6572). also TTP in northern NJ has started corner weighing too. www.ttperformance.net

http://72.14.209.104/search?q=cache:...lnk&cd=5&gl=us

thanks ptrhahn
Reply
Old Nov 5, 2007 | 08:43 PM
  #8  
Troux's Avatar
Senior Member
Tenured Member 15 Years
iTrader: (6)
 
Joined: Jun 2007
Posts: 698
Likes: 0
From: Tampa, Florida
Where did you get those coilovers? And how much were they?
Reply
Old Nov 5, 2007 | 08:46 PM
  #9  
2MCHPWR's Avatar
Thread Starter
FD / LSX
Tenured Member 15 Years
iTrader: (2)
 
Joined: Jun 2004
Posts: 1,359
Likes: 0
From: wawayanda, NY
i got em used. but you can get em new:
http://www.jrzusa.net/products/

although an FD application isn't listed on the price list, they do make them special order:
http://www.jrzusa.net/prices/jrz_prices.pdf
Reply
Old Nov 6, 2007 | 09:33 PM
  #10  
2MCHPWR's Avatar
Thread Starter
FD / LSX
Tenured Member 15 Years
iTrader: (2)
 
Joined: Jun 2004
Posts: 1,359
Likes: 0
From: wawayanda, NY
First Adjustment: I was told motion ratio was .6, so I took a guess on how many turns to lower the rear coilovers. There are about 10-12 rotations per inch. I took a guess to lower the Left Rear 5 turns and the Right Rear 6 turns, and it turned out perfect. Ride height at every corner is now 25.25 inches. Rear sway bar is disconnected but front is still connected. Still 1/4 tank of gas and I will put more in tomorrow night. That will improve the distributions I believe.



The main improvement is that the Cross weights ((RF + LF)/ttl weight) went from 47.8% to 50.2%:coolugh: As per those articles I listed, this is hugely important to be as close to 50% as possible. Mission accomplished.
Tomorrow I hope to do one more measurement by adding more fuel so its a real world weight, and by disconnecting front sway bar (in case there is preload).

I put all the measurements in a spreadsheet here:
www.ponycars.net/cornerweights.htm

I almost got killed because as I was jacking up the rear (fronts already on the scales), the front wheels were being pulled back and fell off the scales and the car rolled back and pinned my shoulders and head against my garage door. I wiggled out. Luckily the door is weak aluminum and dented in easily
Reply
Old Nov 7, 2007 | 10:30 AM
  #11  
adax's Avatar
Senior Member
Tenured Member 15 Years
iTrader: (2)
 
Joined: Aug 2001
Posts: 340
Likes: 1
From: Atlanta
You're probably having the same problem in the rear that I had with my JRZ's in that the lower shock bolt is too short. I'd recommend the following solution before you loose it at a bad time.

https://www.rx7club.com/suspension-wheels-tires-brakes-20/custom-fd-rear-sway-bar-end-links-how-695989/

Alan
Reply
Old Nov 7, 2007 | 11:29 AM
  #12  
aznpoopy's Avatar
strike up the paean
Tenured Member 20 Years
 
Joined: Aug 2003
Posts: 2,495
Likes: 2
From: fort lee, nj
be careful man.

you should really throw some kind of ballast in the driver's spot to simulate your own weight.

edit: nevermind i see it says with driver. i'm seriously having a problem with glossing the reading. i blame school.
Reply
Old Nov 7, 2007 | 09:36 PM
  #13  
2MCHPWR's Avatar
Thread Starter
FD / LSX
Tenured Member 15 Years
iTrader: (2)
 
Joined: Jun 2004
Posts: 1,359
Likes: 0
From: wawayanda, NY
done finally.
added 9 gallons of fuel (gained 58 lbs).
no driver, all swaybars disconnected, 2825 lbs, 49.9% front, 50.1 rear.
With driver, 3033 lbs, 49.2% front, 50.8 rear.
did it on garage cement slab floor. i think its pretty flat. i'll check on another spot but for now, its good enough. rearward weight bias
Reply
Old Nov 8, 2007 | 09:09 PM
  #14  
2MCHPWR's Avatar
Thread Starter
FD / LSX
Tenured Member 15 Years
iTrader: (2)
 
Joined: Jun 2004
Posts: 1,359
Likes: 0
From: wawayanda, NY
ponycars.net

the yellow highlights are when i took the measurements front headed in versus backed in. since floor isn't flat. i took the averages and with me in, front is 49.45% and rear is 50.55%.
Reply
Old Nov 9, 2007 | 10:18 AM
  #15  
owen is fat's Avatar
Rotary Freak
Tenured Member 05 Years
 
Joined: Apr 2004
Posts: 1,579
Likes: 0
From: Rochester, NY
Originally Posted by 2MCHPWR
I almost got killed because as I was jacking up the rear (fronts already on the scales), the front wheels were being pulled back and fell off the scales and the car rolled back and pinned my shoulders and head against my garage door. I wiggled out. Luckily the door is weak aluminum and dented in easily
holy crap man that must have been not fun.
at least throw a tool on the scales to act as a wheel-chock the next time you do any stuff like that, wow.

gives me the shivers.

nice final results though, awesome, you have to be totally stoked on those coilovers, such a nice product.
Reply
Old Nov 9, 2007 | 12:16 PM
  #16  
student13b's Avatar
poor student!!
 
Joined: Oct 2007
Posts: 25
Likes: 0
From: boston
nice good thread im planning to do the same this next year!
Reply
Old Nov 10, 2007 | 12:13 PM
  #17  
adax's Avatar
Senior Member
Tenured Member 15 Years
iTrader: (2)
 
Joined: Aug 2001
Posts: 340
Likes: 1
From: Atlanta
I PM'd 2MCHPWR my cornerweights but I also thought it might be helpful to post here as well for others. This data is for a single turbo '93 with 3/4 tank of gas, me (180#) in the driver's seat, and a Kirk roll bar as the only weight-adding mod. Sway-bars disconnected. Sorry it's not in the cool spread-sheet form but you get the idea.

Weights in pounds

LF = 739 RF = 673
LR = 830 RR = 763

LF + RR cross = 1502 (49.9%)
RF + LR cross = 1503 (50.1%)

L = 51%
R = 49%
F = 47%
R = 53%

Total weight = 3006

F = 5 caster, -1.8 camber, 3 mm toe in
R = -2.0 camber, 5 mm toe in
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ItsJBohmzB
Build Threads
171
Apr 24, 2017 01:11 PM
mazdaverx713b
Build Threads
48
Apr 21, 2016 06:45 AM
Ciclovnz
Build Threads
18
Nov 26, 2015 04:35 AM
CaptainKRM
2nd Generation Specific (1986-1992)
14
Aug 26, 2015 09:52 PM




All times are GMT -5. The time now is 09:59 AM.