Nissan 370Z Forum  

Front Upper Control Arms...

I currently have the SPL front upper control arms. With the way they are designed, they change the SAI angle and hence the scrub radius as you adjust the camber.

Go Back   Nissan 370Z Forum > Nissan 370Z Tech Area > Track / Autocross / Drifting / Dragstrip


Like Tree15Likes

Reply
 
LinkBack Thread Tools Display Modes
Old 11-03-2017, 11:33 PM   #1 (permalink)
Enthusiast Member
 
ValidusVentus's Avatar
 
Join Date: Jun 2011
Location: Washington State
Posts: 400
Drives: #18 Z34
Rep Power: 22
ValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond repute
Default Front Upper Control Arms...

I currently have the SPL front upper control arms.

With the way they are designed, they change the SAI angle and hence the scrub radius as you adjust the camber. As the SAI increases with the camber increase, and working with the caster, it creates more jacking of the car on the inside tire when the wheel is turned, effectively leaning the car away from corners. I tend to view this negatively. (although I do like the increased steering effort and feedback)

Does anyone have any thoughts on this or comparisons to other FUCA designs for the 370 in regards to this line of thought?
__________________
Mods: Dedicated caged track car, lots of things. ||| Valkyrie Autosport |||

Last edited by ValidusVentus; 11-04-2017 at 04:55 PM.
ValidusVentus is offline   Reply With Quote
Old 11-04-2017, 03:10 AM   #2 (permalink)
A True Z Fanatic
 
jchammond's Avatar
 
Join Date: Nov 2014
Location: South Carolina
Age: 57
Posts: 15,204
Drives: 13’ 370Z TS 7A/T
Rep Power: 2684394
jchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond reputejchammond has a reputation beyond repute
Default

I can't personally answer these question's, but from everything i've heard about the SPL brand parts-is nothing but exceptional.
You currently have the best product on your Z...People whom track their car will chime in & give details about the (Steering Axis Inclination) & any other concern's.
You may need some additional part's to achieve best result's.
__________________
MazWorx built long block | FI-TT-100 Stage 2.75 | IPT built 7A/T

http://www.the370z.com/members-370z-...s-musings.html
jchammond is offline   Reply With Quote
Old 11-04-2017, 03:37 AM   #3 (permalink)
A True Z Fanatic
 
Join Date: Dec 2009
Location: 03350 Australia
Posts: 1,502
Drives: 09 Nissan 370Z M6
Rep Power: 29907
BGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond repute
Default

The situation you describe puts more weight on the inside tyre which means it contributes more grip towards turning the car rather than the alternative which places more load on the outside tyre.

remember you get lateral weight transfer when rotating the car and the problem is how to "share" the effort across both front tyres.

I actually think that SPL have it "right" .......

As the car rolls onto the outside front tyre with weight transfer, the effect of the FUCA with increased lock puts more weight onto the inside tyre and so it is able to share more of the available grip rather than letting the outside tyre do "all the work".
DarkJak, GaleForce, Rusty and 3 others like this.
BGTV8 is offline   Reply With Quote
Old 11-04-2017, 04:46 PM   #4 (permalink)
Enthusiast Member
 
ValidusVentus's Avatar
 
Join Date: Jun 2011
Location: Washington State
Posts: 400
Drives: #18 Z34
Rep Power: 22
ValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond repute
Default

Quote:
Originally Posted by BGTV8 View Post
The situation you describe puts more weight on the inside tyre which means it contributes more grip towards turning the car rather than the alternative which places more load on the outside tyre.

remember you get lateral weight transfer when rotating the car and the problem is how to "share" the effort across both front tyres.

I actually think that SPL have it "right" .......

As the car rolls onto the outside front tyre with weight transfer, the effect of the FUCA with increased lock puts more weight onto the inside tyre and so it is able to share more of the available grip rather than letting the outside tyre do "all the work".
Thanks for the reply, you may be correct. But my thoughts are along the following line: in order to increase the actual weight over the inside tire the car has to actually push into the ground harder... and to generate a force its got to be pushing against something else. And the amount of weight transfer is only affected by the CG height, track width and weight of the car. All other factors just affect the roll angle attained. I'm thinking that just because the car raises on one side, that doesn't mean its pushing into the ground harder, the only factor changed by the weight transfer would be how hard it has to work to raise one side of the car or another. ...Or would that force possibly even be transmitted back to the outside tires via the roll bars and springs? My head is starting to hurt.

Admittedly though, only in the very tightest of on track corners would this effect possibly be significant I suppose. With its noticeable effect on the steering weight and self centering I was also considering if it would contribute to almost a pendulum like effect with larger quick corrections; which seems to be something I do feel a bit of. Tough to say.

jchammond I would say I've tracked the car quite a bit but I still like to ponder some of these more difficult to measure things (especially while I don't have access to my car or track time) and was just looking for other's thoughts about it. I agree about SPL, have several of their products on my Z
__________________
Mods: Dedicated caged track car, lots of things. ||| Valkyrie Autosport |||

Last edited by ValidusVentus; 11-04-2017 at 04:51 PM.
ValidusVentus is offline   Reply With Quote
Old 11-05-2017, 01:08 AM   #5 (permalink)
Ronin Samurai - Assassin
 
Rusty's Avatar
 
Join Date: Dec 2011
Location: Fayettenam,Pennsyltucky
Age: 68
Posts: 34,812
Drives: 2011 Nismo GM 6M
Rep Power: 2684436
Rusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond repute
Talking

What are your alignment specs?
__________________

浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html
Rusty is offline   Reply With Quote
Old 11-05-2017, 01:30 PM   #6 (permalink)
A True Z Fanatic
 
Join Date: Dec 2009
Location: 03350 Australia
Posts: 1,502
Drives: 09 Nissan 370Z M6
Rep Power: 29907
BGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond reputeBGTV8 has a reputation beyond repute
Default

Quote:
Originally Posted by ValidusVentus View Post
Thanks for the reply, you may be correct. But my thoughts are along the following line: in order to increase the actual weight over the inside tire the car has to actually push into the ground harder... and to generate a force its got to be pushing against something else. And the amount of weight transfer is only affected by the CG height, track width and weight of the car. All other factors just affect the roll angle attained. I'm thinking that just because the car raises on one side, that doesn't mean its pushing into the ground harder, the only factor changed by the weight transfer would be how hard it has to work to raise one side of the car or another. ...Or would that force possibly even be transmitted back to the outside tires via the roll bars and springs? My head is starting to hurt.

Admittedly though, only in the very tightest of on track corners would this effect possibly be significant I suppose. With its noticeable effect on the steering weight and self centering I was also considering if it would contribute to almost a pendulum like effect with larger quick corrections; which seems to be something I do feel a bit of. Tough to say.

jchammond I would say I've tracked the car quite a bit but I still like to ponder some of these more difficult to measure things (especially while I don't have access to my car or track time) and was just looking for other's thoughts about it. I agree about SPL, have several of their products on my Z
We are talking about "jacking". If you can use suspension setting to "jack" the inside of the car when turning, especially when you are starting the turn and wanting the car to rotate, the act of arranging suspension to "push" down on the road with steering input (eg: LHF with turn to the left), then there will be an equal and opposite reaction of the road surface pushing against the tyre which will improve grip available from that tyre until the roll moment starts the take over.

Take a peek at the smithees website (URL) below where he goes into it in some depth.

Race Car Suspension Set-Up
ValidusVentus and Rusty like this.
BGTV8 is offline   Reply With Quote
Old 11-05-2017, 08:43 PM   #7 (permalink)
Enthusiast Member
 
Join Date: Aug 2016
Location: SoCal
Age: 31
Posts: 383
Drives: Infiniti FX35
Rep Power: 35
MaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond repute
Default

The SR does not change in this situation. Only the SAI. The SR would only change if you changed the angle of the upright and not the camber and caster.

The only way you'd change the SR is if you change the wheel offset, or somehow modify the upright to change inclination.

Jacking would be increased during turning if you increased caster angle. In this case, don't increase caster.
MaysEffect is offline   Reply With Quote
Old 11-06-2017, 02:35 PM   #8 (permalink)
Enthusiast Member
 
ValidusVentus's Avatar
 
Join Date: Jun 2011
Location: Washington State
Posts: 400
Drives: #18 Z34
Rep Power: 22
ValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond reputeValidusVentus has a reputation beyond repute
Default

Quote:
Originally Posted by MaysEffect View Post
The SR does not change in this situation. Only the SAI. The SR would only change if you changed the angle of the upright and not the camber and caster.

The only way you'd change the SR is if you change the wheel offset, or somehow modify the upright to change inclination.

Jacking would be increased during turning if you increased caster angle. In this case, don't increase caster.
The design of the SPL FUCAs is such that it adds camber by changing the actual length of the upper A arm.

And I tried to go to the link above but it doesn't seem to work on the gov computers unfortunately, they never seem to like links that end in a foreign abbreviation.
__________________
Mods: Dedicated caged track car, lots of things. ||| Valkyrie Autosport |||
ValidusVentus is offline   Reply With Quote
Old 11-06-2017, 04:04 PM   #9 (permalink)
Enthusiast Member
 
Join Date: Aug 2016
Location: SoCal
Age: 31
Posts: 383
Drives: Infiniti FX35
Rep Power: 35
MaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond repute
Default

Quote:
Originally Posted by ValidusVentus View Post
The design of the SPL FUCAs is such that it adds camber by changing the actual length of the upper A arm.
Right. This only changes the SAI. Because the change in geometry also changes the wheel center line angle, there is no change in SR.

If you increase caster along with camber you will have increased rise and fall.

Adding stiffer components won't help much here. It would mostly just make steering more sensitive.
ValidusVentus likes this.
MaysEffect is offline   Reply With Quote
Old 11-06-2017, 05:56 PM   #10 (permalink)
Ronin Samurai - Assassin
 
Rusty's Avatar
 
Join Date: Dec 2011
Location: Fayettenam,Pennsyltucky
Age: 68
Posts: 34,812
Drives: 2011 Nismo GM 6M
Rep Power: 2684436
Rusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond repute
Talking

Quote:
Originally Posted by ValidusVentus View Post
The design of the SPL FUCAs is such that it adds camber by changing the actual length of the upper A arm.

And I tried to go to the link above but it doesn't seem to work on the gov computers unfortunately, they never seem to like links that end in a foreign abbreviation.
Any adjustable control arm for the Z will change the distance between the ball-joint and the control arm pivots. If you want to change the camber. There is no way around it. You have to live with it. The only way to get around what you are describing, is to move the control arm pivots in or out. Ain't going to happen. With the SPL's. Now you can change the caster too. Slicks need caster. Go to Hooser's web site. They will tell you to run as much + caster that you can. When you start making changes, you will have to live with the compromises.
ValidusVentus likes this.
__________________

浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html
Rusty is offline   Reply With Quote
Old 11-06-2017, 07:47 PM   #11 (permalink)
Enthusiast Member
 
Join Date: Aug 2016
Location: SoCal
Age: 31
Posts: 383
Drives: Infiniti FX35
Rep Power: 35
MaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond repute
Default

Quote:
Originally Posted by Rusty View Post
... . With the SPL's. Now you can change the caster too. Slicks need caster. Go to Hooser's web site. They will tell you to run as much + caster that you can. When you start making changes, you will have to live with the compromises.
That's an extremely vague suggestion that should be taken with a grain of salt.

Racing tires needed additional camber, adding positive caster is another way of getting more camber with additional steering lock. The tires dont need caster, in most cases its worse for the tires as it pulls the tire away from the road.

Increased negative scrub and wider tires is necessary if you increase camber and caster.
ValidusVentus and Brendan like this.
MaysEffect is offline   Reply With Quote
Old 11-06-2017, 08:02 PM   #12 (permalink)
Ronin Samurai - Assassin
 
Rusty's Avatar
 
Join Date: Dec 2011
Location: Fayettenam,Pennsyltucky
Age: 68
Posts: 34,812
Drives: 2011 Nismo GM 6M
Rep Power: 2684436
Rusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond repute
Talking

Quote:
Originally Posted by MaysEffect View Post
That's an extremely vague suggestion that should be taken with a grain of salt.

Racing tires needed additional camber, adding positive caster is another way of getting more camber with additional steering lock. The tires dont need caster, in most cases its worse for the tires as it pulls the tire away from the road.

Increased negative scrub and wider tires is necessary if you increase camber and caster.
A little info from Toyo tires.

Toyo Tires recommends the following general set-up guidelines for the Proxes R888:

Operating Temperature: 160°F to 220°F
Hot Inflation Pressures: 32 to 38 (psi)
Camber: -1° to -3°
Caster: As much positive as possible
__________________

浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html
Rusty is offline   Reply With Quote
Old 11-06-2017, 08:54 PM   #13 (permalink)
Premium Member
 
Hotrodz's Avatar
 
Join Date: Aug 2012
Location: NW, AZ
Posts: 9,330
Drives: 10 Nissan 370z Nismo
Rep Power: 2684384
Hotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond reputeHotrodz has a reputation beyond repute
Default

Quote:
Originally Posted by Rusty View Post
A little info from Toyo tires.

Toyo Tires recommends the following general set-up guidelines for the Proxes R888:

Operating Temperature: 160°F to 220°F
Hot Inflation Pressures: 32 to 38 (psi)
Camber: -1° to -3°
Caster: As much positive as possible
My r888 setup:
Hot Inflation Pressure: less than 36 psi tire will get squirrelly 36 psi or better.
Camber: -2.26 front -2.00 rear
Caster: 6.5 and I think 7 to 8 would be better

There was another member here running -3.3 front and -1.8 rear with caster at 8 for the same tire. He was running 18x315 and I am running 18x295.
Rusty likes this.
__________________
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|
Hotrodz is offline   Reply With Quote
Old 11-06-2017, 10:59 PM   #14 (permalink)
Ronin Samurai - Assassin
 
Rusty's Avatar
 
Join Date: Dec 2011
Location: Fayettenam,Pennsyltucky
Age: 68
Posts: 34,812
Drives: 2011 Nismo GM 6M
Rep Power: 2684436
Rusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond reputeRusty has a reputation beyond repute
Talking

Quote:
Originally Posted by Hotrodz View Post
My r888 setup:
Hot Inflation Pressure: less than 36 psi tire will get squirrelly 36 psi or better.
Camber: -2.26 front -2.00 rear
Caster: 6.5 and I think 7 to 8 would be better

There was another member here running -3.3 front and -1.8 rear with caster at 8 for the same tire. He was running 18x315 and I am running 18x295.
Yeah, I'm running -2.0 camber and +7 caster front and -1.75 camber rear.
__________________

浪人 - 殺し屋
"The Difficult Anytime, The Impossible By Appointment Only"
http://www.the370z.com/members-370z-...o-journal.html
Rusty is offline   Reply With Quote
Old 11-07-2017, 12:27 AM   #15 (permalink)
Enthusiast Member
 
Join Date: Aug 2016
Location: SoCal
Age: 31
Posts: 383
Drives: Infiniti FX35
Rep Power: 35
MaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond reputeMaysEffect has a reputation beyond repute
Default

Quote:
Originally Posted by Rusty View Post
A little info from Toyo tires.

Toyo Tires recommends the following general set-up guidelines for the Proxes R888:

Operating Temperature: 160°F to 220°F
Hot Inflation Pressures: 32 to 38 (psi)
Camber: -1° to -3°
Caster: As much positive as possible
That is equally vague. 32-38psi covers a huge variety of load ranges of about 300ibs per axle. 2 degrees of camber variation is also a huge margin for both steering geometry and tire contact. Changing the caster by that amount (4 degrees to 6 degrees) would possibly change your camber at full lock by 1-4 degrees.

This also doesn't take into account the wide variety of suspension setups these tire companies are advertising to. Cars without sway bars, cars with solid rear axles, cars with McPherson struts.

None of this is a problem for the Z. So additional caster AND camber is not a necessary change, its the reason nissan knocked the Z34 down to -+5 degrees of caster. If you want more response out of the tires, properly match the SR for the given wheel/tire you are trying to use. Not an easy thing to do when dealing with clearance and fitment issues (brakes or fenders). So yes, this is the ultimate compromise. Adding caster and camber ruins your instantaneous roll center. Something that will severely compromise how the suspension balance SHOULD be setup.
MaysEffect is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[FOR SALE] SPL Front Upper Control Arms Dirk McGurck Parts for sale (Private Classifieds) 16 05-26-2017 09:11 PM
[FOR SALE] SoCal: SPL Rear Camber Arms, SPC Front Upper Control Arms, and 20mm/25mm Spacers NoHyperbole Parts for sale (Private Classifieds) 7 01-27-2017 09:41 AM
[FOR SALE] Front upper control arms guzmanb66 Parts for sale (Private Classifieds) 1 11-08-2016 10:23 AM
Spl Front upper control arms! xxZxx Wanted 5 04-05-2016 09:51 PM
[FOR SALE] SPL Front upper control arms xxZxx Parts for sale (Private Classifieds) 7 01-19-2016 10:17 PM


All times are GMT -5. The time now is 03:38 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 PL2