TronDD Tim Meunier Mega Moderator Location: Boston, MA Join Date: 10/27/2011 Age: Midlife Crisis Posts: 252 Rally Car: 96 Subaru Impreza |
Question one, why is there a bushing on every connection in the rear? I mean the diff mounts. Is there any real reason not to have solid mounts for the diff, crossmember, and "t-bone"? Is it just vibration dampening?
Question B, is it a good idea to make tubular rear arms with spherical rod ends? Eliminates the rubber, looks like it can be done cheaply. I've also seen some people recommend leaving rubber bushings to absorb impacts. Looks like it would be a fun project, though. Tim. |
john vanlandingham John Vanlandingham Senior Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
1) NVH---engineers spend millions reducing it
2) you would be very smart to explore that idea...anything would be better than the OEM curtain rods being passed off as "links" I suggest you think about 3/4" rod ends because there just might be people making Subie width plug in spacers copied from Fords brilliant design. The pre swaged tubes cost jus a few dollars each--27" ones are like 14 bucks, Subies are all shorter, so even less. It is madness that every Subie doesn't have something like this---and if they're not bending them every 203 SSs then ---well we know how the average car is "driven" John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
Reamer Jeff Reamer Infallible Moderator Location: Marlette, Michigan Join Date: 08/14/2010 Age: Midlife Crisis Posts: 489 Rally Car: Subaru |
The diff and t bar need to still move some that helps with traction. Every thing else I would make solid. Hiems do tend to rattle after they get a thous or to loose.Never tried high dollor teflon heims but the cheap aurora hiems and the $150.00 ebay adjustable links will make noise. So if you cant handle the noise I would go polly.
First rally 2013 Rally car type AWD subaru Total rallies as driver 6 Total rally cars built 2 Total rally cars caged 3 Total rally cars repaired from offs 4 Total years racing exp other then rally 19 yrs Like 31motorsports on FB! Check out 31motor sales on ebay for used Subaru parts |
TronDD Tim Meunier Mega Moderator Location: Boston, MA Join Date: 10/27/2011 Age: Midlife Crisis Posts: 252 Rally Car: 96 Subaru Impreza |
How so? Noise isn't an issue unless you mean I might think the joints are broken. Obviously annoyance noises are exceptable in a rally car. I've heard speculation that the teflon bearings can have the teflon beaten out of them in rough conditions and then you will get some rattling. Tim. |
mke723 Mike Lindenfelser Mod Moderator Location: Minnesnowta Join Date: 10/17/2012 Age: Midlife Crisis Posts: 154 Rally Car: 1995 Impreza L |
Also interested in how letting the diff twist under torque load would HELP with traction? Loss of power to the wheels means less loss of traction? I be sorry as a muthafucka I did, still sorry I did n' hustled ta peep what tha fuck I holla'd a lil' bit better, or at least try to. |
Reamer Jeff Reamer Infallible Moderator Location: Marlette, Michigan Join Date: 08/14/2010 Age: Midlife Crisis Posts: 489 Rally Car: Subaru |
When you hit the throttle the pinion gear tries to climb the ring gear on the rear diff. when this happens the dif,pig will try to flip over. the mounts stop this fromn happening. so when it lifts it tries to lift at the center of the car. Thats why the t-bar hooks tawards the center of the car. If it is solid that load goes straight to the tires and breaks them loose. By giving the diff some give it will help slow down the inital shock and help the tires make traction on acceleration. This goes both ways thow. when you let off the throttle in theory it will try to lift the rear tires off the ground.
First rally 2013 Rally car type AWD subaru Total rallies as driver 6 Total rally cars built 2 Total rally cars caged 3 Total rally cars repaired from offs 4 Total years racing exp other then rally 19 yrs Like 31motorsports on FB! Check out 31motor sales on ebay for used Subaru parts |
TronDD Tim Meunier Mega Moderator Location: Boston, MA Join Date: 10/27/2011 Age: Midlife Crisis Posts: 252 Rally Car: 96 Subaru Impreza |
Coming from muscle cars and listening to drag racers, this sounds like a similar scenario.
On a muscle car, live rear axle, the pinion climbs the ring gear pointing the pinion up. So drag racers use the force by installing traction bars or ladder bars or what have you sort of in the lower control arm area going towards the middle of the car. Same concept as the t bar? However, these bars are usually solid because we use the movement of the twisting diff to push down, via the bars, on the tires, *increasing* traction. Opposite of your assertion with the Subaru. Even if does work differently on the Subie, does it even matter outside of a hard launch on pavement ? Tim. |
Reamer Jeff Reamer Infallible Moderator Location: Marlette, Michigan Join Date: 08/14/2010 Age: Midlife Crisis Posts: 489 Rally Car: Subaru |
Solid for pavement rubber for dirt. Dirt cars have all sorts of gismos to try to keep the tire planted on the ground. any shock will break traction.Its still lifting like the drag car just softens the initial hit. I believe even drag cars at a slick trac would benifit from some movment. Thinking more along guys crying that the right lane sucks or if a guy were street racing where traction is iffy. Now if you have a huge tire and traction isnt an issue then yes movment up isnt movment foward. so solid would be better.
Lots of guys with the sti subarus call it the sti clunk. its when theres tons of traction and it sounds like it bangs the floor boards. In 08 they did away with the t bar and mounted it at the front of the diff. Where the bar mounts also affects how the car brakes slows. high speed with sweeping easy corners will be more stable with the longer t bar. shorter bars closer to the pionion responds faster but can break traction easier. The car will rotate easier under braking and be more ready for throttle quicker. WHEN theres traction with a shorter arm. For rally I would maybe go with polly but I wouldnt go solid. First rally 2013 Rally car type AWD subaru Total rallies as driver 6 Total rally cars built 2 Total rally cars caged 3 Total rally cars repaired from offs 4 Total years racing exp other then rally 19 yrs Like 31motorsports on FB! Check out 31motor sales on ebay for used Subaru parts |
TronDD Tim Meunier Mega Moderator Location: Boston, MA Join Date: 10/27/2011 Age: Midlife Crisis Posts: 252 Rally Car: 96 Subaru Impreza |
After thinking about it some more, I see what you're saying. We want the pinion to move a little otherwise the shock goes right to the tires. The example for a drag car would be wrinkle wall slicks. You let the tire deform a little to absorb the shock.
I guess I'll default to, leave well enough alone. Don't change it just because. Back to thinking about some tubular arms, then... Tim. |
john vanlandingham John Vanlandingham Senior Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
You get that stupid long bolt out of the bottom of the knuckle? PB Blaster and HEAT....
And anti-seize on the reassembly. (was that you?) John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
TronDD Tim Meunier Mega Moderator Location: Boston, MA Join Date: 10/27/2011 Age: Midlife Crisis Posts: 252 Rally Car: 96 Subaru Impreza |
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john vanlandingham John Vanlandingham Senior Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
PB Blaster and heat and Bronze or aluminum drift...that bolt is expensive and you mooosh over the end and it hain't comin out. John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
Greg Donovan Greg Donovan Elite Moderator Location: Fargo, ND Join Date: 04/12/2007 Age: Midlife Crisis Posts: 423 Rally Car: 95 Impreza Sedan |
that bolt can suck it. Words cannot express my full hatred of that long bolt. |
john vanlandingham John Vanlandingham Senior Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Dude, you may have noticed I have use a phrase before "engineering fads", right? well engineers hang out with other engineers and (who else would!!!) read engineering journals where they drone on in stultifyingly boring tones about idiotic trivialities and so further destoy their already Abbey Normal Brains, and so its not surprising that you see the same "ideeers" or "solutions " popping up suddenly in nearby areas.. That dumb way long bolt passing thru cast iron rear knuckle thing is one such sudden fad and appeared on way too many Japonaise cars all of a sudden...and they seize in place on all of them... The honorable thing to do would be for people to forward their stories to the companies in Japan and offer to act as the engineers who designed those things "Second",or kaishakunin that's the guy standing just behind the disgraced engineer in the photo...You job will be to end things before the guy has dishonored himself by crying or crapping his pants or starts explaining what they were thinking when they designed this abomination that always rusts solid---or whatever.. There will be blood.. John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
Reamer Jeff Reamer Infallible Moderator Location: Marlette, Michigan Join Date: 08/14/2010 Age: Midlife Crisis Posts: 489 Rally Car: Subaru |
We all hate those damn bolts! Here in Michigan your lucky if they break loose on a car with 10k miles on it. I literally have at least 14 spindles sitting here needing the damn bolts taken out. Ive been trying to come up with a good plan that doesnt wreck the arms and that damn bolt. still seems that a torch,pb and burning out the rubber is the only way. You still need new bushings and at that point im loosing $ on trying to resell the lateral links.
First rally 2013 Rally car type AWD subaru Total rallies as driver 6 Total rally cars built 2 Total rally cars caged 3 Total rally cars repaired from offs 4 Total years racing exp other then rally 19 yrs Like 31motorsports on FB! Check out 31motor sales on ebay for used Subaru parts |