Lets See Those Custom Parts v.2023
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2winscroll (Sep 23, 2021)
Sep 22, 2021, 06:50 PM
#857
Normally a spherical has 3 degrees of freedom (yaw, pitch and roll). This has just 2 degrees of freedom, the slot allows it to yaw (if you were looking at it from top down view) and of course it can pitch to allow arm motion. When you articulate the entire suspension the trailing arm has an ever so slight amount of yaw movement to accommodate the arc swings of the other arms. I could've definitely used a smaller slot but I figured having extra space for movement wouldn't hurt anything.
I'd have to double check a stock arm but I recall the SSB arm being wider than stock because the poly bushings we used have a thinner flange than stock. Regardless, yes I could've done something similar to the stock design even if the stock pieces didn't fit but those pieces would still create some amount of bind in the suspension and would alter wheel rate because they're made of rubber. With an all metal suspension I know that there's no rubber or poly to muck up wheel rates.
Here's a video with all the sphericals installed. Can articulate the entire suspension with 2 fingers. The limiter is the toe arm hitting the chassis (which is long after the tire has hit the chassis). It all feels very smooth so I'm pleased with how it turned out.
http://www.youtube.com/watch?v=xmD9knHyU7o
I'd have to double check a stock arm but I recall the SSB arm being wider than stock because the poly bushings we used have a thinner flange than stock. Regardless, yes I could've done something similar to the stock design even if the stock pieces didn't fit but those pieces would still create some amount of bind in the suspension and would alter wheel rate because they're made of rubber. With an all metal suspension I know that there's no rubber or poly to muck up wheel rates.
Here's a video with all the sphericals installed. Can articulate the entire suspension with 2 fingers. The limiter is the toe arm hitting the chassis (which is long after the tire has hit the chassis). It all feels very smooth so I'm pleased with how it turned out.
http://www.youtube.com/watch?v=xmD9knHyU7o
I guess my main question is why design a custom spherical bearing even if you can prove the arm at that point has two degrees of freedom while assembled? Why pinch pennies when leaving it a true spherical is also possible?
Looking forward to seeing some data or results on suspension charateristics with this modification.
Sep 22, 2021, 08:46 PM
#858
Thanks for confirming my suspicion that your spherical bearing is 2 degrees of freedom. That's the first time I have seen that and I have reverse engineered countless products since its my job. I dont know how that it would work in a rear suspension setup because of suspension adjustability as a whole assembly.
I guess my main question is why design a custom spherical bearing even if you can prove the arm at that point has two degrees of freedom while assembled? Why pinch pennies when leaving it a true spherical is also possible?
Looking forward to seeing some data or results on suspension charateristics with this modification.
I guess my main question is why design a custom spherical bearing even if you can prove the arm at that point has two degrees of freedom while assembled? Why pinch pennies when leaving it a true spherical is also possible?
Looking forward to seeing some data or results on suspension charateristics with this modification.
The fact is, you can't leave that joint as an unconstrained spherical because of the high likelihood of wheel contact. The purpose of the video was to show that the suspension is functioning properly with sphericals at every joint. As for "pinching pennies" it actually would've been cheaper to leave it an unconstrained spherical. Since I had to have the slot it meant making the housing on a lathe and then machining the slot in on a mill. Even having them go through 2 machines the housings still cost me under $100.
It's no different than when you put a spherical in the lower shock mount on the lower control arm in the rear. Since all 3 joints are sphericals in that situation the arm is able to freely roll around its axis parallet to the length of the arm because all three sphericals have 3 degrees of freedom. With the arm able to freely roll it will slap back and forth in the lower shock fork.
Keep in mind, when I'm talking about this trailing arm yaw motion, it is very minor, just a few mm of movement. Even though it's a small amount it's still necessary since the trailing arm sits mostly perpendicular to the upper and lower arms. Imagine you're looking at the rear suspension from behind, when the upper and lower arms are parallel to the ground they are at the most outboard point in their travel arcs, and when they're at max or min distance (in terms of wheel travel up or down) in either direction from parallel they are at their most inboard points in their arcs. Since these arcs cause the wheel to move inboard and outboard, the trailing arm must be able to yaw to account for that displacement. If you don't let the trailing arm yaw it will bind pretty quickly and your suspension travel would be severely limited.
One of the least brought up concepts about suspension is the fact than every measurement and calculation you make at your static ride height will change as the car moves through a corner. Many people understand this with camber curves but more than just camber changes. For example, when you go through a corner your roll centers are moving, your contact patches are moving, and your track width is growing or shrinking depending on how much the suspension is being displaced. Understanding these dynamic kinematic relationships is crucial to having a suspension system that functions well.
These things can be pretty hard to demonstrate without a physical model or picture presentations so I'm sorry if my explanation comes across poorly.
Last edited by Ayoustin; Sep 22, 2021 at 09:14 PM.
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Sep 23, 2021, 05:14 PM
#859
The bearing isn't custom, it's a standard sized bearing that is available from any pillow ball/spherical bearing manufacturer. I'm not quite sure what you're asking when you say "true spherical". It is required to eliminate roll out of the trailing arm or it will be allowed to flop into the wheel and tire, hence the constraining slot. The factory achieves this constraint by putting rubber pucks on both sides of the arm which keeps it from rolling but the rubber can compress as the arm yaws while the wheel goes up and down.
The fact is, you can't leave that joint as an unconstrained spherical because of the high likelihood of wheel contact. The purpose of the video was to show that the suspension is functioning properly with sphericals at every joint. As for "pinching pennies" it actually would've been cheaper to leave it an unconstrained spherical. Since I had to have the slot it meant making the housing on a lathe and then machining the slot in on a mill. Even having them go through 2 machines the housings still cost me under $100.
It's no different than when you put a spherical in the lower shock mount on the lower control arm in the rear. Since all 3 joints are sphericals in that situation the arm is able to freely roll around its axis parallet to the length of the arm because all three sphericals have 3 degrees of freedom. With the arm able to freely roll it will slap back and forth in the lower shock fork.
Keep in mind, when I'm talking about this trailing arm yaw motion, it is very minor, just a few mm of movement. Even though it's a small amount it's still necessary since the trailing arm sits mostly perpendicular to the upper and lower arms. Imagine you're looking at the rear suspension from behind, when the upper and lower arms are parallel to the ground they are at the most outboard point in their travel arcs, and when they're at max or min distance (in terms of wheel travel up or down) in either direction from parallel they are at their most inboard points in their arcs. Since these arcs cause the wheel to move inboard and outboard, the trailing arm must be able to yaw to account for that displacement. If you don't let the trailing arm yaw it will bind pretty quickly and your suspension travel would be severely limited.
One of the least brought up concepts about suspension is the fact than every measurement and calculation you make at your static ride height will change as the car moves through a corner. Many people understand this with camber curves but more than just camber changes. For example, when you go through a corner your roll centers are moving, your contact patches are moving, and your track width is growing or shrinking depending on how much the suspension is being displaced. Understanding these dynamic kinematic relationships is crucial to having a suspension system that functions well.
These things can be pretty hard to demonstrate without a physical model or picture presentations so I'm sorry if my explanation comes across poorly.
The fact is, you can't leave that joint as an unconstrained spherical because of the high likelihood of wheel contact. The purpose of the video was to show that the suspension is functioning properly with sphericals at every joint. As for "pinching pennies" it actually would've been cheaper to leave it an unconstrained spherical. Since I had to have the slot it meant making the housing on a lathe and then machining the slot in on a mill. Even having them go through 2 machines the housings still cost me under $100.
It's no different than when you put a spherical in the lower shock mount on the lower control arm in the rear. Since all 3 joints are sphericals in that situation the arm is able to freely roll around its axis parallet to the length of the arm because all three sphericals have 3 degrees of freedom. With the arm able to freely roll it will slap back and forth in the lower shock fork.
Keep in mind, when I'm talking about this trailing arm yaw motion, it is very minor, just a few mm of movement. Even though it's a small amount it's still necessary since the trailing arm sits mostly perpendicular to the upper and lower arms. Imagine you're looking at the rear suspension from behind, when the upper and lower arms are parallel to the ground they are at the most outboard point in their travel arcs, and when they're at max or min distance (in terms of wheel travel up or down) in either direction from parallel they are at their most inboard points in their arcs. Since these arcs cause the wheel to move inboard and outboard, the trailing arm must be able to yaw to account for that displacement. If you don't let the trailing arm yaw it will bind pretty quickly and your suspension travel would be severely limited.
One of the least brought up concepts about suspension is the fact than every measurement and calculation you make at your static ride height will change as the car moves through a corner. Many people understand this with camber curves but more than just camber changes. For example, when you go through a corner your roll centers are moving, your contact patches are moving, and your track width is growing or shrinking depending on how much the suspension is being displaced. Understanding these dynamic kinematic relationships is crucial to having a suspension system that functions well.
These things can be pretty hard to demonstrate without a physical model or picture presentations so I'm sorry if my explanation comes across poorly.
Sep 23, 2021, 05:52 PM
#860
Its all about degrees of freedom. If you have nothing controlling rotation then it can do what ever it wants and in the case of the trailing arm shape gravity will pull it down till something stops it. This is bad cause if its hitting something hard then suspension travels may decide to pushing it against a hard point on the chasses. Or it may sit against one of the sphericals limits. Rubber isolators to keep the arm clocked is totally fine too.
The arm itself moves along a couple different planes. If you clock the origin of the spherical you have the plane it moves vertically, the in/out relative to the car (this may seem minor but its not, camber, toe, suspension travel all do this), and then the plan orthogonal to those two. It cant translate on that plane but it can rotate. This is what the slots on Austins bushing control. It lets it move on the two planes needed but stops the rotation on the last plane. I can confirm, it is correct and also what I would do.
The arm itself moves along a couple different planes. If you clock the origin of the spherical you have the plane it moves vertically, the in/out relative to the car (this may seem minor but its not, camber, toe, suspension travel all do this), and then the plan orthogonal to those two. It cant translate on that plane but it can rotate. This is what the slots on Austins bushing control. It lets it move on the two planes needed but stops the rotation on the last plane. I can confirm, it is correct and also what I would do.
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alpinaturbo (Sep 24, 2021)
Sep 23, 2021, 08:57 PM
#861
Evolved Member
It’s preturbo water injection. You get all the benifits of post turbo water injection with the added benefit of improving compressor efficiency by cooling the charge inside the scroll. It’s been proven to shift the compressor map to the right, increasing airflow capabilities up to fifteen percent while lowering intake charge temps. The only downfall is if the water is not well atomized it can erode the compressor wheel. The system is simplistic and uses boost pressure to supply water and atomize the water through an HVLP spray nozzle. Another issue is since it’s straight water you need a very good ignition system to light the mixture. Tractor pullers have been using similar setups for years on limited inducer class racing, most use a pump instead of boost pressure to supply the water.
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alpinaturbo (Sep 24, 2021)
Sep 24, 2021, 08:19 AM
#862
It’s preturbo water injection. You get all the benifits of post turbo water injection with the added benefit of improving compressor efficiency by cooling the charge inside the scroll. It’s been proven to shift the compressor map to the right, increasing airflow capabilities up to fifteen percent while lowering intake charge temps. The only downfall is if the water is not well atomized it can erode the compressor wheel. The system is simplistic and uses boost pressure to supply water and atomize the water through an HVLP spray nozzle. Another issue is since it’s straight water you need a very good ignition system to light the mixture. Tractor pullers have been using similar setups for years on limited inducer class racing, most use a pump instead of boost pressure to supply the water.
Sep 24, 2021, 08:23 AM
#863
Normally a spherical has 3 degrees of freedom (yaw, pitch and roll). This has just 2 degrees of freedom, the slot allows it to yaw (if you were looking at it from top down view) and of course it can pitch to allow arm motion. When you articulate the entire suspension the trailing arm has an ever so slight amount of yaw movement to accommodate the arc swings of the other arms. I could've definitely used a smaller slot but I figured having extra space for movement wouldn't hurt anything.
I'd have to double check a stock arm but I recall the SSB arm being wider than stock because the poly bushings we used have a thinner flange than stock. Regardless, yes I could've done something similar to the stock design even if the stock pieces didn't fit but those pieces would still create some amount of bind in the suspension and would alter wheel rate because they're made of rubber. With an all metal suspension I know that there's no rubber or poly to muck up wheel rates.
Here's a video with all the sphericals installed. Can articulate the entire suspension with 2 fingers. The limiter is the toe arm hitting the chassis (which is long after the tire has hit the chassis). It all feels very smooth so I'm pleased with how it turned out.
http://www.youtube.com/watch?v=xmD9knHyU7o
I'd have to double check a stock arm but I recall the SSB arm being wider than stock because the poly bushings we used have a thinner flange than stock. Regardless, yes I could've done something similar to the stock design even if the stock pieces didn't fit but those pieces would still create some amount of bind in the suspension and would alter wheel rate because they're made of rubber. With an all metal suspension I know that there's no rubber or poly to muck up wheel rates.
Here's a video with all the sphericals installed. Can articulate the entire suspension with 2 fingers. The limiter is the toe arm hitting the chassis (which is long after the tire has hit the chassis). It all feels very smooth so I'm pleased with how it turned out.
http://www.youtube.com/watch?v=xmD9knHyU7o
Sep 24, 2021, 08:59 AM
#864
Evolved Member
I ran a distilled water injection system on my Gen 2 Eclipse turbo years ago for road/race. It does displace the air/fuel with water, but the water makes up for it in HP by allowing more timing/boost. It does this by cooling the charge, the combustion event, and slowing the flame front (making the fuel burn at a rate like a much higher octane) The setup shown above in that picture however has a LARGE contraption blocking the airflow into the turbo inlet. My setup only had a small nozzle after the intercooler. That setup shown is going to block airflow pretty badly IMO. I would burn through a washer tank of distilled water in a 30-40min track session at the Glenn. It was the only mod that I could feel the increase in power, but my EGT gauge would DROP....
Sep 24, 2021, 09:05 AM
#865
On octane limited setups the various forms of water/alcohol injection are great (assuming there are safeties built in). But to Marshals point, on E85 or Race gas there's little benefit because you're not gaining much in the way of boost or timing above what you already can get. So you get cooler charge out of a turbo but is that gain offset by the displaced oxygen? Marshal says no. My gut says the squeeze isn't worth the juice here with the added complexity and potential for failure.
Sep 24, 2021, 10:12 AM
#866
- 1.25" bar, comes in 5 different wall thicknesses
- Adjustable arms, 4 (may change to 5) points of adjustment, give a total of 7 (or 9) stiffness settings
- Adjustment points on a fixed radius keep endlink lengths consistent and makes for quick setting changes
- Mounted on bearings, no deflection and minimal friction
Just put in the order for metal prototypes this week. Should have more fun photos to share soon.
The following 5 users liked this post by Ayoustin:
alpinaturbo (Sep 24, 2021),
Construct (Sep 24, 2021),
MrAWD (Sep 27, 2021),
RSMike (Mar 18, 2022),
Segfault (Sep 26, 2021)
Sep 24, 2021, 11:07 AM
#867
Evolved Member
It’s preturbo water injection. You get all the benifits of post turbo water injection with the added benefit of improving compressor efficiency by cooling the charge inside the scroll. It’s been proven to shift the compressor map to the right, increasing airflow capabilities up to fifteen percent while lowering intake charge temps. The only downfall is if the water is not well atomized it can erode the compressor wheel. The system is simplistic and uses boost pressure to supply water and atomize the water through an HVLP spray nozzle. Another issue is since it’s straight water you need a very good ignition system to light the mixture. Tractor pullers have been using similar setups for years on limited inducer class racing, most use a pump instead of boost pressure to supply the water.
man, I used identical setup in the early nineties on my turboed high compression bmw 732i to solve det problem... worked a treat
Sep 24, 2021, 12:20 PM
#868
Evolved Member
On octane limited setups the various forms of water/alcohol injection are great (assuming there are safeties built in). But to Marshals point, on E85 or Race gas there's little benefit because you're not gaining much in the way of boost or timing above what you already can get. So you get cooler charge out of a turbo but is that gain offset by the displaced oxygen? Marshal says no. My gut says the squeeze isn't worth the juice here with the added complexity and potential for failure.
Sep 24, 2021, 12:39 PM
#869
Yeah me too. Back in 04-05 I had water/meth and it was great for making power but it was pretty janky cause there was a delay between pump on and water spraying. I know now they have better solutions but then I had to prime the pump before a pull. I did wire a hobbs switch in the water line run to a boost solenoid to run WG pressure till the water had enough pressure. Like I said, janky.. But it was better than straight pump.
E85 totally changed the game. I tossed that old kit with a quickness and never looked back.
E85 totally changed the game. I tossed that old kit with a quickness and never looked back.
Sep 24, 2021, 03:34 PM
#870
Evolved Member
Here is a simple question for you, does E85 have a boost limit? (You know, those nasty two words called Detonation and Preignition)
Oh and another one, how much boost do you run and what horsepower are you making?
Last edited by 2winscroll; Sep 24, 2021 at 03:55 PM.