Suspension: When to adjust what? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Race Prep Miata race-only chat.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 02-22-2011, 05:47 PM   #21
Elite Member
iTrader: (2)
 
Join Date: Jun 2006
Location: ABQ, NM
Posts: 1,850
Total Cats: -8
Default

Quote:
Originally Posted by hustler View Post
...and the corner with all the weight is the corner that doesn't steer, correct? If my front left is heavy, could that explain why steady-state right-turns are a story of miserable understeer?



If you have pronounced and miserable understeer turning in only one direction, while the other direction feels great, you have something else going on.
BenR is offline   Reply With Quote
Old 02-22-2011, 06:59 PM   #22
Senior Member
iTrader: (1)
 
Join Date: May 2008
Location: south texas
Posts: 1,419
Total Cats: 9
Default

Quote:
Originally Posted by hustler View Post
...and the corner with all the weight is the corner that doesn't steer, correct? If my front left is heavy, could that explain why steady-state right-turns are a story of miserable understeer?
not necessarily. if your corner balanced it should steer roughly the same in either direction. corner balancing doesn't mean the weights are gonna be equal at all corners. only that the lf & rr , and rf & lr are similar in weight.
which means you could have 150lbs. lf / 50lbs rr = 200lbs.
then 125lbs rf / 75lbs lr = 200lbs. and hypothetically have similar steering left or right. in this example the lf has more weight than any corner, but it shouldn't steer differently. what could, especially at that track cw, is higher temps from all the right hand turns. it could raise the tire psi, more on one side and that could affect the handling. on jakes car we ran 2psi less cold on the left and after the session they were all equal.
spoolin2bars is offline   Reply With Quote
Old 02-23-2011, 09:48 AM   #23
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

This Mark Ortiz stuff is awesome.
hustler is offline   Reply With Quote
Old 02-23-2011, 11:08 AM   #24
Elite Member
iTrader: (2)
 
Join Date: Jun 2006
Location: ABQ, NM
Posts: 1,850
Total Cats: -8
Default

If you haven't already you should subscribe to racecar engineering, if for nothing else but the ****.


http://www.racecar-engineering.com/


This is supposed to be a very good book. A bit heavy on the maths, keeping your college texts nearby would be helpful.

http://www.millikenresearch.com/rcvd.html
BenR is offline   Reply With Quote
Old 02-23-2011, 02:38 PM   #25
Elite Member
iTrader: (13)
 
Join Date: Nov 2006
Location: Tigard, Oregon
Posts: 3,908
Total Cats: 0
Default

Quote:
Originally Posted by hustler View Post
This Mark Ortiz stuff is awesome.
Holy crap he's got a lot of information. I figured it would all be FWD stuff since they run Hondas but it's not. Definetely worth spending time looking through.
cueball1 is offline   Reply With Quote
Old 02-23-2011, 07:32 PM   #26
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

Quote:
Originally Posted by cueball1 View Post
Holy crap he's got a lot of information. I figured it would all be FWD stuff since they run Hondas but it's not. Definetely worth spending time looking through.
Mark's a Racecar Engineer / Consultant. I think those Honda guys are just storing some of his material on their site.

Seriously guys…at first some enthusiasts buy a cool car…many do some bling mods…a few do motor mods…some learn to drive…some modify the suspension…combinations. There are many ways to enjoy automobiles. If you get into track / autocross, it really pays to learn the fundamentals of suspensions and handling, keep records, try to improve your setup, datalog, make parts, video, read, discuss.

Miatadotnet is pretty much for everybody…CR more for the bling/slam crowd…this place (to me) seems mostly about the motor, engine, boost etc (which makes sense given the forum name and the interest of many posters). It's nice to see a few here showing interest in learning more about suspension and handling rather than the latest boost mod. After all…it's not hard to hold the gas pedal down

Now…Mark is mostly used to dealing with experienced and pro drivers. I point this out because some enthusiasts leap to making all sorts of changes to their car to get rid of problems the car may or may not really have. You can really get lost if you go down that path. It's pretty common.

See…the driver can experience a car and then when trying to produce a good result may need to develop a driving strategy which may or may not be as expected. Since they will do things like take different lines, enter corners certain ways, give it up in other places than others. That's part of how the SM guys can produce quite decent lap time results on about any track.
sjmarcy is offline   Reply With Quote
Old 02-23-2011, 09:09 PM   #27
Elite Member
iTrader: (2)
 
Join Date: Jun 2006
Location: ABQ, NM
Posts: 1,850
Total Cats: -8
Default

Quote:
Originally Posted by sjmarcy View Post
Mark's a Racecar Engineer / Consultant. I think those Honda guys are just storing some of his material on their site.

Seriously guys…at first some enthusiasts buy a cool car…many do some bling mods…a few do motor mods…some learn to drive…some modify the suspension…combinations. There are many ways to enjoy automobiles. If you get into track / autocross, it really pays to learn the fundamentals of suspensions and handling, keep records, try to improve your setup, datalog, make parts, video, read, discuss.

Miatadotnet is pretty much for everybody…CR more for the bling/slam crowd…this place (to me) seems mostly about the motor, engine, boost etc (which makes sense given the forum name and the interest of many posters). It's nice to see a few here showing interest in learning more about suspension and handling rather than the latest boost mod. After all…it's not hard to hold the gas pedal down

Now…Mark is mostly used to dealing with experienced and pro drivers. I point this out because some enthusiasts leap to making all sorts of changes to their car to get rid of problems the car may or may not really have. You can really get lost if you go down that path. It's pretty common.

See…the driver can experience a car and then when trying to produce a good result may need to develop a driving strategy which may or may not be as expected. Since they will do things like take different lines, enter corners certain ways, give it up in other places than others. That's part of how the SM guys can produce quite decent lap time results on about any track.



So the point of this post is to yet again claim you know a lot and we dumb powerheads not only don't know much, but can't drive, and we should be glad you're part of this forum? Way to stick on topic.
BenR is offline   Reply With Quote
Old 02-23-2011, 09:50 PM   #28
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by BenR View Post
So the point of this post is to yet again claim you know a lot and we dumb powerheads not only don't know much, but can't drive, and we should be glad you're part of this forum? Way to stick on topic.
Again, rather than contribute to the thread, he "listens to the sound of his own voice". He also fails to notice that roughly 100% of the fastest Miatas in the nation are on this board, and we didn't get here without fundamentals.
hustler is offline   Reply With Quote
Old 02-24-2011, 12:06 AM   #29
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

Quote:
Originally Posted by sjmarcy View Post
four paragraphs of the same elitist bullshit nonsense I normally post and nobody reads
Go ruin a thread on M.net with this crap. Race Prep is sacred ground and you're incapable of doing anything except shitting all over it.
Savington is offline   Reply With Quote
Old 02-24-2011, 12:31 AM   #30
Senior Member
iTrader: (5)
 
Join Date: Jan 2008
Location: Central, TX / Bay area, CA
Posts: 1,272
Total Cats: 3
Default

Quote:
Originally Posted by sjmarcy View Post
Mark's a Racecar Engineer / Consultant. I think those Honda guys are just storing some of his material on their site.

Seriously guys…at first some enthusiasts buy a cool car…many do some bling mods…a few do motor mods…some learn to drive…some modify the suspension…combinations. There are many ways to enjoy automobiles. If you get into track / autocross, it really pays to learn the fundamentals of suspensions and handling, keep records, try to improve your setup, datalog, make parts, video, read, discuss.

Miatadotnet is pretty much for everybody…CR more for the bling/slam crowd…this place (to me) seems mostly about the motor, engine, boost etc (which makes sense given the forum name and the interest of many posters). It's nice to see a few here showing interest in learning more about suspension and handling rather than the latest boost mod. After all…it's not hard to hold the gas pedal down

Now…Mark is mostly used to dealing with experienced and pro drivers. I point this out because some enthusiasts leap to making all sorts of changes to their car to get rid of problems the car may or may not really have. You can really get lost if you go down that path. It's pretty common.

See…the driver can experience a car and then when trying to produce a good result may need to develop a driving strategy which may or may not be as expected. Since they will do things like take different lines, enter corners certain ways, give it up in other places than others. That's part of how the SM guys can produce quite decent lap time results on about any track.
This section is mainly for those who run faster times than spec miata, and who think out side of the box, not those who drive what comes out of a box.
Gotpsi? is offline   Reply With Quote
Old 02-24-2011, 01:02 AM   #31
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,105
Total Cats: 518
Default

Quote:
Originally Posted by hustler View Post
...and the corner with all the weight is the corner that doesn't steer, correct? If my front left is heavy, could that explain why steady-state right-turns are a story of miserable understeer?
Have you tried this?

http://www.flyinmiata.com/projects/OTC/race.php?day=5
curly is offline   Reply With Quote
Old 02-24-2011, 01:11 AM   #32
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

You have to be careful with generalizing all right turns too. I spent some time trying to figure out why the black car wouldn't turn in for T10 at Laguna, until I realized that it was perfect everywhere else and T10 just naturally causes understeer from the terrain.
Savington is offline   Reply With Quote
Old 02-24-2011, 09:39 AM   #33
Elite Member
iTrader: (7)
 
Join Date: Jan 2008
Location: Knoxville, TN
Posts: 2,118
Total Cats: 44
Default

Quote:
Originally Posted by sjmarcy View Post

After all…it's not hard to hold the gas pedal down

It is coming down T11 at Road Atlanta!
flier129 is offline   Reply With Quote
Old 02-24-2011, 10:08 AM   #34
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by Savington View Post
You have to be careful with generalizing all right turns too. I spent some time trying to figure out why the black car wouldn't turn in for T10 at Laguna, until I realized that it was perfect everywhere else and T10 just naturally causes understeer from the terrain.
Yes, my tears result from one corner. The difference is that 17-year-old children in $$$ SM's were trouncing me through here and I could not go fast on the rest of the track due to the tears clouding my vision.

What did you do to add some speed in this turn? Hotter entry and harder trail brake?
hustler is offline   Reply With Quote
Old 02-24-2011, 01:44 PM   #35
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

Quote:
Originally Posted by hustler View Post

What did you do to add some speed in this turn? Hotter entry and harder trail brake?
Yep. Move the braking point up ~75ft and ride the brakes the whole way through turn-in until it's basically over-rotated. There's so much camber in T10 that if you don't over-rotate on entry, you'll be fully hooked before the apex and pushing on exit. I got through there fast one time at my last Laguna day, and the steering wheel was straight the entire time.
Savington is offline   Reply With Quote
Old 02-25-2011, 03:26 PM   #36
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

So today, I read this and it blew my mind
http://www.eviltwinmotorsports.com/w...ter-2006.6.pdf :
Quote:
As to the effect of shocks, yes stiffening the fronts will add understeer during entry and stiffening the rears will add oversteer, provided that the road surface is smooth. This effect requires that the car have a roll velocity outward, and that this be the main source of suspension movement. When the car is cornering steady-state on a smooth surface, the roll velocity should be zero, the suspension should have displacement from static but not velocity, and shocks shouldn't matter. During exit, the car has a roll velocity inward (it's de-rolling). In this situation, the effect of the shocks reverses. Stiffening the fronts adds oversteer; stiffening the rears adds understeer.

So to add understeer or oversteer overall, we use the relative stiffness of the front and rear springs (and/or bars, if present). To change entry and exit properties in opposite directions, we use the relative stiffness of the front and rear shocks (remember, only on smooth surfaces).
I'm suddenly unsure which way to turn the rebound ****.
hustler is offline   Reply With Quote
Old 02-25-2011, 03:29 PM   #37
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by Savington View Post
Yep. Move the braking point up ~75ft and ride the brakes the whole way through turn-in until it's basically over-rotated. There's so much camber in T10 that if you don't over-rotate on entry, you'll be fully hooked before the apex and pushing on exit. I got through there fast one time at my last Laguna day, and the steering wheel was straight the entire time.
This feels applicable to my thread. Man, I'm getting to a point where sometimes I feel like I'm overdriving when I do stuff like this, but people like you agree it's faster. I do something similar at Hallett at #1 and #5, MSR-C CW through the triple apex, and now MSRH Sugar and Spice. This is specifically pertinent to Hallett where some of the DFW crew attempted to give me advice, while they're 5-seconds behind of course.
hustler is offline   Reply With Quote
Old 02-25-2011, 03:34 PM   #38
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

A damper's job in high shaft speed is to keep the tire on the surface, and in a perfect world over bumps with no change in load. What is the damper's job in low speed, glass smooth weight transfer?

I know low-speed compression is there to control roll to the magical number that works on every track, but what does rebound specifically do?

I'll ask questions later about the gray area between high and low speed, and the magical shim-stack transitions from high to low. This is getting scary, I may want 3-way adjustables soon.
hustler is offline   Reply With Quote
Old 02-25-2011, 03:36 PM   #39
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

Quote:
Originally Posted by Savington View Post
Yep. Move the braking point up ~75ft and ride the brakes the whole way through turn-in until it's basically over-rotated. There's so much camber in T10 that if you don't over-rotate on entry, you'll be fully hooked before the apex and pushing on exit. I got through there fast one time at my last Laguna day, and the steering wheel was straight the entire time.
Yup, I'd do the same. By getting more rotation earlier on such a turn, mid and and corner exit understeer and steering lock is reduced, and powerdown can be earlier. This is a key autocross driving skill too BTW. Combine with well timed throttle kicks for alien driving at those speeds. It helps alot to have good brake bias here.
sjmarcy is offline   Reply With Quote
Old 02-25-2011, 03:38 PM   #40
Tour de Franzia
Thread Starter
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by sjmarcy View Post
Yup, I'd do the same. By getting more rotation earlier on such a turn, mid and and corner exit understeer and steering lock is reduced, and powerdown can be earlier. This is a key autocross driving skill too BTW. Combine with well timed throttle kicks for alien driving at those speeds. It helps alot to have good brake bias here.
hustler is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Someone help me with AE ihiryu MEGAsquirt 33 10-08-2015 05:56 PM
MSPNPPro-MM0105: Coolant Temperature Output slomiata MEGAsquirt 5 10-07-2015 02:11 PM
Twitchy car (tail happy problem) bigben Race Prep 16 09-11-2015 04:41 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:37 PM.