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Rear suspension setup. (let's settle this)
03-23-06 | 01:28 PM
#1
Thread Starter
Rotary Freak
Joined: Dec 2003
Posts: 2,117
Likes: 2
From: Waukesha Wisconsin
Rear suspension setup. (let's settle this)
With the auto-X season on the horizon, I am becoming more and more pressed to make this decision.
What is the optimum rear suspension setup for and FB?
--Stiff front end with sway bars and polly bushings, and soft rear end with no sway bar and new (effective) rubber bushings.
OR
--Stiff front end and rear end, with both stock sway bars or larger aftermarket bars in place and polly bushings all around.
I have a full RB susspension setup (uninstalled) for my car. this kit came with larger front AND rear sway bars. It also included polly sway bar bushings for both the front and the rear.
This leads me to believe that as a matched set, front and rear bars work well togeather and are more desireable than no rear bar at all. The inclusion of polly bushings in the kit leads me to believe that stiffness in at least some (and perhaps all) locations of the rear suspension is also benificial.
Is racing beat selling a poorly matched setup for our cars and calling it a ballanced system comprised of pieces chosen to work well togeather?
I'd like input from all of you with experiance in this area (I'm also including a poll).
Testimonials from those who have run one or both setups would be great.
And feed back from those running the racing beat package would be particularly of interest to me.
I'd love to get the general consensus of the FB community in one thread. I hope it works.
Thanks,
--Alex
What is the optimum rear suspension setup for and FB?
--Stiff front end with sway bars and polly bushings, and soft rear end with no sway bar and new (effective) rubber bushings.
OR
--Stiff front end and rear end, with both stock sway bars or larger aftermarket bars in place and polly bushings all around.
I have a full RB susspension setup (uninstalled) for my car. this kit came with larger front AND rear sway bars. It also included polly sway bar bushings for both the front and the rear.
This leads me to believe that as a matched set, front and rear bars work well togeather and are more desireable than no rear bar at all. The inclusion of polly bushings in the kit leads me to believe that stiffness in at least some (and perhaps all) locations of the rear suspension is also benificial.
Is racing beat selling a poorly matched setup for our cars and calling it a ballanced system comprised of pieces chosen to work well togeather?
I'd like input from all of you with experiance in this area (I'm also including a poll).
Testimonials from those who have run one or both setups would be great.
And feed back from those running the racing beat package would be particularly of interest to me.
I'd love to get the general consensus of the FB community in one thread. I hope it works.
Thanks,
--Alex
Last edited by Alex-7; 03-23-06 at 01:33 PM.
03-23-06 | 02:02 PM
#2
real solution: http://www.gforceengineering.net/products.htm
or Cheap compromise setup:
--Stiff front end with 1 1/8" front sway bar and poly bushings, and soft rear end with no sway bar and new rubber bushings everywhere in the rear. Make sure you get a good alignment with as much negative camber and positive caster as possible, set Toe to 1/8" IN.
or Cheap compromise setup:
--Stiff front end with 1 1/8" front sway bar and poly bushings, and soft rear end with no sway bar and new rubber bushings everywhere in the rear. Make sure you get a good alignment with as much negative camber and positive caster as possible, set Toe to 1/8" IN.
03-23-06 | 04:09 PM
#3
Full Member
Joined: Apr 2003
Posts: 163
Likes: 0
From: San Ramon, CA
Depends on the type of differential you have--open or limited-slip. If open, then DriveFast's solution is the way to go. The car will understeer and you'll have to muscle it through the course, but acceleration out of the turns is everything.
03-23-06 | 04:57 PM
#4
Thread Starter
Rotary Freak
Joined: Dec 2003
Posts: 2,117
Likes: 2
From: Waukesha Wisconsin
Originally Posted by DriveFast7
real solution: http://www.gforceengineering.net/products.htm
or Cheap compromise setup:
--Stiff front end with 1 1/8" front sway bar and poly bushings, and soft rear end with no sway bar and new rubber bushings everywhere in the rear. Make sure you get a good alignment with as much negative camber and positive caster as possible, set Toe to 1/8" IN.
or Cheap compromise setup:
--Stiff front end with 1 1/8" front sway bar and poly bushings, and soft rear end with no sway bar and new rubber bushings everywhere in the rear. Make sure you get a good alignment with as much negative camber and positive caster as possible, set Toe to 1/8" IN.
The gforce stuff is very nice, but I really don't want to get that deep into things.
Nick: what would be the choice for a limited slip car then?
I'd love to get a little input from the guys who have voted for stiff/stiff. Please elaborate.
Last edited by Alex-7; 03-23-06 at 04:59 PM.
03-23-06 | 05:12 PM
#5
racing beat springs are a nice kit. non-progressive so the suspension sets quickly (unlike eibach pro kit which is progressive but a smoother ride on the street).
I had RB springs in my rx7 for years. Cut several coils off, real stiff and LOW. Handeled good, took offramps at nice speeds. Of course it is a compromise; g force sells the real deal stuff but is pricey.
As for LSD, have it rebuilt with new clutch discs and even an oversided disc. Tighten things right up.
I had RB springs in my rx7 for years. Cut several coils off, real stiff and LOW. Handeled good, took offramps at nice speeds. Of course it is a compromise; g force sells the real deal stuff but is pricey.
As for LSD, have it rebuilt with new clutch discs and even an oversided disc. Tighten things right up.
03-23-06 | 07:57 PM
#6
Just a suggestion for the front
www.racersareme.com
The advantage of soft rear is squat, which allows the car to launch quickly so it is good for autocrossing, hard rear is better for fast corners not very helpful for autocrossing
www.racersareme.com
The advantage of soft rear is squat, which allows the car to launch quickly so it is good for autocrossing, hard rear is better for fast corners not very helpful for autocrossing
03-23-06 | 08:25 PM
#7
Old [Sch|F]ool
Joined: May 2001
Posts: 12,634
Likes: 464
From: Cleveland, Ohio, USA
The overriding concern IMO is launching the car out of corners. You want to be able to put the power down to the ground to blast out of a corner harder, sooner.
This generally means the rear is softer than the front, so the majority of the total vehicle roll stiffness is at the front end. Roll stiffness is "weight" transfer, and weight transfer means poorer traction.
In a nutshell, and overlooking about a bazillion other things.
This generally means the rear is softer than the front, so the majority of the total vehicle roll stiffness is at the front end. Roll stiffness is "weight" transfer, and weight transfer means poorer traction.
In a nutshell, and overlooking about a bazillion other things.
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03-23-06 | 09:13 PM
#8
Lives on the Forum
Joined: Jun 2004
Posts: 11,359
Likes: 14
From: Grand Rapids Michigan
Racing Beat has been in the business for a long time, and have a pretty good reputation as far as knowing what they are doing. Are there better setups out there? Sure there are, but they will involve dishing out much more $$$.
I would install the entire setup as is, and then try it out and see if you like it. If you end up with too much oversteer then you could either disconnect the rear sway bar or put the old one back on (depending on how bad it is).
I would install the entire setup as is, and then try it out and see if you like it. If you end up with too much oversteer then you could either disconnect the rear sway bar or put the old one back on (depending on how bad it is).
03-23-06 | 09:30 PM
#9
keep it original!!
iTrader: (3)
Joined: Oct 2005
Posts: 1,329
Likes: 8
From: SF Bay Area, California
i dont know much about drifting well but from my little experiences with my stock gsl it did fine losing traction by hitting the gas and turn hard... or maybe im think of power sliding
03-23-06 | 09:32 PM
#10
Full Member
Joined: Feb 2006
Posts: 195
Likes: 0
From: Chicago Suburbs, 815
Originally Posted by bwaits
First, ANY suspension system and setup is a compromise. Even a F1 car's suspension has elements that are a compromise. Each style of suspension, each method of attaching and each material choice used are compromises. As long as everyone realizes this simple fact we can start to understand why it takes race teams years to "develop" a seemingly simple tin top race cars suspension.
Second, production cars are mass produced for the general population. The general population wants to fell comfortable driving their car. Comfortable in two way as well. The first way is a comfortable ride without harshness. The second way is to feel comfortable and not scared when turning. These two facts are why most production cars have understeer built in to the suspension design and why the suspension bushings are soft and compliant.
Third, only believe 10% of what you read and hear. This will work, that won't work, my guy said this, his dad once did the other thing......Most of the time these statement come from people who are just passing off bad information and do not understand the concept themselves anyways. Besides the fact that the average person will not feel the difference on most minor suspension changes.
You should now understand that the first generation rx7 has a suspension design under it that has built in understeer, a soft feeling comfortable ride and the entire system is a compromise. We have all heard the tail that Mazda did not use a pan hard bar because it would have made the car bla bla longer. This is an example of a compromise in the design stage.
Now that we understand the above information we can start to figure out the suspension of the rx7. The rear setup is a 4 link setup. There are 4 arms that server to locate the axle front to back as well as to keep the axle from rotating. These 4 arms are not the same length. These 4 arms are not mounted to the chassis in the same location from side to side. This means when the suspension moves in bump and droop the axle is moving along an arc. This is a fact. You can not do anything about this unless you move the arm pickup points to better locations and use better designed arm lengths. If we are talking about street cars I doubt you are ready to change those aspects of the suspension system.
The axle also needs some device to locate it from side to side. Mazda chose the Watts linkage to do this. Mazda made a compromise and used a offset mounting for this device. It controls the side to side movement with a price though. The price we pay for the use of the stock watts is that the axle is bound to move up and down vertically. Remember from before the 4 link design has the axle moving in a arc and now the watts linkage makes it want to only move vertical. There you have the "Bind" always talked about.
The reason the binding is not a big deal in the stock form is due to the second statement from above. Production cars use soft rubber bushings to give comfort. These comfortable bushings just so happen to also give the compliance needed to let the axle not bind when moving. Now if we were to replace all the stock bushings with a much harder rubber the compliance would be gone and the system would bind up. If we strategically replace bushings we can obtain a firmer location of the axle and still have the compliance needed to not bind up. Start with the lower arms. If we replace these with firmer bushings the suspension will still move freely and the axel would be located front to rear firmer than factory. If we replaced the watts linkage bushings the axle is now located side to side firmer than factory. We start to see a small amount of tension (I did not want to say bind) in the system. We are still at a good point though because some of the arc movement is taken up by the soft upper arm bushings. Now if we leave one of the stock bushings in the watts pivot point the arc motion would be taken up by the soft bushings in the upper arms and the axle can pivot slightly on the watts bracket. We have located the axle firmer than factory but not introduce a severe amount of bind doing it.
We have just had to compromise our suspension bushings choice due to circumstances we can not easily change. Every suspension system is a compromise.
-billy
Second, production cars are mass produced for the general population. The general population wants to fell comfortable driving their car. Comfortable in two way as well. The first way is a comfortable ride without harshness. The second way is to feel comfortable and not scared when turning. These two facts are why most production cars have understeer built in to the suspension design and why the suspension bushings are soft and compliant.
Third, only believe 10% of what you read and hear. This will work, that won't work, my guy said this, his dad once did the other thing......Most of the time these statement come from people who are just passing off bad information and do not understand the concept themselves anyways. Besides the fact that the average person will not feel the difference on most minor suspension changes.
You should now understand that the first generation rx7 has a suspension design under it that has built in understeer, a soft feeling comfortable ride and the entire system is a compromise. We have all heard the tail that Mazda did not use a pan hard bar because it would have made the car bla bla longer. This is an example of a compromise in the design stage.
Now that we understand the above information we can start to figure out the suspension of the rx7. The rear setup is a 4 link setup. There are 4 arms that server to locate the axle front to back as well as to keep the axle from rotating. These 4 arms are not the same length. These 4 arms are not mounted to the chassis in the same location from side to side. This means when the suspension moves in bump and droop the axle is moving along an arc. This is a fact. You can not do anything about this unless you move the arm pickup points to better locations and use better designed arm lengths. If we are talking about street cars I doubt you are ready to change those aspects of the suspension system.
The axle also needs some device to locate it from side to side. Mazda chose the Watts linkage to do this. Mazda made a compromise and used a offset mounting for this device. It controls the side to side movement with a price though. The price we pay for the use of the stock watts is that the axle is bound to move up and down vertically. Remember from before the 4 link design has the axle moving in a arc and now the watts linkage makes it want to only move vertical. There you have the "Bind" always talked about.
The reason the binding is not a big deal in the stock form is due to the second statement from above. Production cars use soft rubber bushings to give comfort. These comfortable bushings just so happen to also give the compliance needed to let the axle not bind when moving. Now if we were to replace all the stock bushings with a much harder rubber the compliance would be gone and the system would bind up. If we strategically replace bushings we can obtain a firmer location of the axle and still have the compliance needed to not bind up. Start with the lower arms. If we replace these with firmer bushings the suspension will still move freely and the axel would be located front to rear firmer than factory. If we replaced the watts linkage bushings the axle is now located side to side firmer than factory. We start to see a small amount of tension (I did not want to say bind) in the system. We are still at a good point though because some of the arc movement is taken up by the soft upper arm bushings. Now if we leave one of the stock bushings in the watts pivot point the arc motion would be taken up by the soft bushings in the upper arms and the axle can pivot slightly on the watts bracket. We have located the axle firmer than factory but not introduce a severe amount of bind doing it.
We have just had to compromise our suspension bushings choice due to circumstances we can not easily change. Every suspension system is a compromise.
-billy
he posted that in the "im ordering bushings" thread
03-23-06 | 11:40 PM
#11
OK, well I know the poly bushings arent best suited for all the links in the rear, but howcome no one ever talks about the PB&J mod? Is it just not known about? or is it just a cheap fix? I have a set of poly bushings and I would like to use them all if I possibly can, anyone care to pipe in about the PB&J mod?
(for those that dont know, their fix for the poly bushings being to hard for the upper links, is to drill 8 holes right through the bushings before installing them, easing up on just how firm the bushings are when the geometry fun kicks in)
(for those that dont know, their fix for the poly bushings being to hard for the upper links, is to drill 8 holes right through the bushings before installing them, easing up on just how firm the bushings are when the geometry fun kicks in)
03-24-06 | 09:58 AM
#12
Thread Starter
Rotary Freak
Joined: Dec 2003
Posts: 2,117
Likes: 2
From: Waukesha Wisconsin
Originally Posted by Gen1onr
anyone care to pipe in about the PB&J mod?
(for those that dont know, their fix for the poly bushings being to hard for the upper links, is to drill 8 holes right through the bushings before installing them, easing up on just how firm the bushings are when the geometry fun kicks in)
(for those that dont know, their fix for the poly bushings being to hard for the upper links, is to drill 8 holes right through the bushings before installing them, easing up on just how firm the bushings are when the geometry fun kicks in)
Thanks for all input so far.
03-24-06 | 10:07 AM
#13
Thread Starter
Rotary Freak
Joined: Dec 2003
Posts: 2,117
Likes: 2
From: Waukesha Wisconsin
Originally Posted by boyee
i dont know much about drifting well but from my little experiences with my stock gsl it did fine losing traction by hitting the gas and turn hard... or maybe im think of power sliding
T
F
?
03-24-06 | 07:12 PM
#14
03-24-06 | 08:25 PM
#15
Old [Sch|F]ool
Joined: May 2001
Posts: 12,634
Likes: 464
From: Cleveland, Ohio, USA
Originally Posted by Gen1onr
OK, well I know the poly bushings arent best suited for all the links in the rear, but howcome no one ever talks about the PB&J mod? Is it just not known about? or is it just a cheap fix? I have a set of poly bushings and I would like to use them all if I possibly can, anyone care to pipe in about the PB&J mod?
(for those that dont know, their fix for the poly bushings being to hard for the upper links, is to drill 8 holes right through the bushings before installing them, easing up on just how firm the bushings are when the geometry fun kicks in)
(for those that dont know, their fix for the poly bushings being to hard for the upper links, is to drill 8 holes right through the bushings before installing them, easing up on just how firm the bushings are when the geometry fun kicks in)
Oh yes, the "PB&J Mod", because nobody had ever drilled holes in bushings before.
No matter what you do, the upper links are going to suck hardcore. Making the bushings floppy just invites other problems. What is needed is the... ultimate solution. *cue dramatic music*
But seriously... nobody could have prepared me for how much flat-out BETTER a 3 link is than the bindfest that is the stock 4-link. I had to experience it for myself.
The only downside is that, now that the rear suspension is free to move, you *really* notice how short the links are.Er? Let's review. Roll steer is provided by the outermost links, when the car leans the suspension arms don't move straight up and down at the axle ends, they move in arcs, and this arc pulls the ends of the axle fore or aft, depending. With the stock 4-link, even when the suspension moves, the geometrical bind caused all of the bushings to kinda mush around and the roll steer is muffled. Throw the upper links away and the roll steer is 100% determined by the lower links. Then you notice it. On bumpy roads, the car kinda gets antsy as the rear axle steers one way or the other depending on which wheel is on a bump or in a depression.
I'd noticed this a little with the 200 pound springs in the rear. When I put the stockers back in, it got *reeeal* noticeable.
I plan on replacing the stock 19" lowers with arms as long as i can physically package in the car.
03-24-06 | 09:21 PM
#16
That crazy Peejay... only a bazillion other things? 
Before you hang any parts on the car take the 'cliff notes' way of learning about the FB suspension and buy the GForce book by Susko that will explain everything. The $75 you will spend can be made back by selling some of the RB stuff you won't want after reading the book.
Before you hang any parts on the car take the 'cliff notes' way of learning about the FB suspension and buy the GForce book by Susko that will explain everything. The $75 you will spend can be made back by selling some of the RB stuff you won't want after reading the book.
03-25-06 | 08:31 AM
#17
Originally Posted by Alex-7
Is racing beat selling a poorly matched setup for our cars and calling it a ballanced system comprised of pieces chosen to work well togeather?
Racing Beat has always been notorious for being on the conservative side.
-billy
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