Chassis bushings, why no manufacturer or vendor just make higher durometer?

[OICU812]

@Racecomp Engineering @CSG Mike


Ok hard to get proper point across in a thread title so here it goes.

I've been thinking about this..

We all have seen and know how products like Whiteline Sub frame bushings take up the slack and gap compared to OEM. We see the benifits and I have them and even in first spirited drives they're evident. However I am also very aware of how them being made of poly/hard plastics they transmit more nvh.

Then I get to thinking... Why has no after market manufacturer or specialist in such things not made basically a copy "size/thickness" of WL or variant (thicker/larger then stock)..wise of these products but simply in a more durable and possibly slightly higher durometer? Seems that would remove gap as the existing products do, and also transmit no more or very little more nvh?

Wondering what I might be missing in this logic? Sorry if this seems silly, but it's been bugging me abit.

[OrbitalEllipses]

The inserts are your standard street performance upgrade. Whiteline makes stiffer full replacement bushings that would be considered the "race" upgrade.

The first has less NVH, the second has more.

A third option for NVH is rubber - high duro rubber actually requires less maintenance than urethane and has lower NVH properties...but I've only ever seen one manufacturer of upgraded rubber mounts: the OEM (STi Group N, etc.). There's not really a way to get less deflection/squishyness AND less NVH.

Unless I misunderstood your question, that's my two cents.

[Racecomp Engineering]

I think Orbital got it. The other thing, inserts are cheap and easy to install.

The Group N STI stuff is good...sometimes expensive and/or hard to install. But good.

[OICU812]

Originally Posted by OrbitalEllipses

The inserts are your standard street performance upgrade. Whiteline makes stiffer full replacement bushings that would be considered the "race" upgrade.

The first has less NVH, the second has more.

A third option for NVH is rubber - high duro rubber actually requires less maintenance than urethane and has lower NVH properties...but I've only ever seen one manufacturer of upgraded rubber mounts: the OEM (STi Group N, etc.). There's not really a way to get less deflection/squishyness AND less NVH.

Unless I misunderstood your question, that's my two cents.

I should have been more specific yes I suppose I was speaking of the inserts themselves being rubber instead of poly, or as you're speaking of a full replacement but thicker and rubber. STI Group N for those specifics being the two diff points, cross member, and forward axle inserts in the Group N I had no idea existed??... I'll need to browse for these, thanks!!

[OrbitalEllipses]

There's not Group-N parts for this car to my knowledge, @OICU812. As a part of Group-N rally, Subaru had to offer the bushings it made for the WRX STI. These were hard durometer rubber replacements available to the market in the exact spec the race cars used as Group-N is a homologation production class of rally.

There was a whole catalog of bushings for the Impreza that STI offered.

EDIT: For this car they offer the trans support, engine mounts, rear subframe bushings, steering rack bushings, differential carrier bushings (all high duro rubber), several rear suspension arms.

On the Impreza they had a majority of the bushings in the suspension: http://www.rallispec.com/mou_bush_rstbk1.html

[OICU812]

Originally Posted by OrbitalEllipses

There's not Group-N parts for this car to my knowledge, @OICU812. As a part of Group-N rally, Subaru had to offer the bushings it made for the WRX STI. These were hard durometer rubber replacements available to the market in the exact spec the race cars used as Group-N is a homologation production class of rally.

There was a whole catalog of bushings for the Impreza that STI offered.

Ahh ok gotcha, thanks for all that clarification. So really in simplicity deal with stock or just do the existing insert or full on and all it a day I suppose. Most accessible cost effective route anyhow.

I've been considering just taking out my subframe inserts, installing stock back in..and trying the cusco bottom rear tie bar to reduce nvh to cabin but I've never seen or heard of a direct comparison of inserts/bushings vs tie bar either, so not sure if that's even worth time or money...

Thanks again guys.

[mrk1]

I had the whiteline full replacement bushings in my 08 sti, same style rear end. I put them in with my subframe completely off the car and in a press. It was still a juggle to install them. So on my brz I just went with the inserts.

[OrbitalEllipses]

Originally Posted by mrk1

I had the whiteline full replacement bushings in my 08 sti, same style rear end. I put them in with my subframe completely off the car and in a press. It was still a juggle to install them. So on my brz I just went with the inserts.

I was talking with the boys down at the shop and they said unless you can do it yourself it's just not worth it labor-wise. They did it for someone and it ended up being something like 6 hours of labor PLUS the alignment for dropping the sub-frame. Inserts are the winner for 95% of people.

[7thgear]

i bought group-n bushings for almost all the point of my impreza, they were cheap

then i found out about the labout involved of pressing things in and out... now i have them in a box somewhere

instead i just got STi components (aluminum front control arms and rear lateral links) as well as an 04 STi rear crossmember, which comes with solid aluminum inserts mounts (no rubber what so ever) still came out cheaper than if i would have had soemone do all teh pressing and fitting.

so yeah, unless you have the time, the space, and the equipment, the market is very poor for this type of upgrade

[Racecomp Engineering]

Originally Posted by 7thgear

i bought group-n bushings for almost all the point of my impreza, they were cheap

then i found out about the labout involved of pressing things in and out... now i have them in a box somewhere

instead i just got STi components (aluminum front control arms and rear lateral links) as well as an 04 STi rear crossmember, which comes with solid aluminum inserts mounts (no rubber what so ever) still came out cheaper than if i would have had soemone do all teh pressing and fitting.

so yeah, unless you have the time, the space, and the equipment, the market is very poor for this type of upgrade

This is a good way to go. More upfront cost but piece of cake install.

- Andy

[unsurety]

Anyone have STI diff mount bushings? Or anything similar, like higher durometer as mentioned in the OP?



RCE made a thread on these, though I don't see them on their site nor do I see anyone comment about them.

http://www.ft86club.com/forums/showthread.php?t=33512

I figure, STI engine + tranny + diff mounts would be expensive, but the best compromise for a daily/weekend warrior.

[Captain Snooze]

http://www.powerflex.co.uk/black-ser...Z+-2825/1.html <---- harder/stiffer (that's what she said) than ---->
http://www.powerflex.co.uk/road-seri...RZ-2817/1.html

I have purchased, not yet installed, Megan Racing front lca bushes. Unscientific test: pushing in a Phillips head screwdriver into the Megan unit offers a metric truck load more resistance than stock.

[Jive Turkey]

the other reason stuff like this doesn't really exist is because well...not many would buy it.

to install the bushings and not hte inserts you need a press and some technical know how. the bushing wouldn't cost a lot but the labor would be immense to have a shop put them in. thus most customers dont even bother because the return on the mod/$ spent isn't that high.

so basically this type of mod/install is tailored to a very select group of owners, most people who mod don't even understand how bushing would even help let alone theres no scene points awarded for stiff chassis mod you cna't see

[Captain Snooze]

Originally Posted by Jive Turkey

let alone theres no scene points awarded for stiff chassis mod you cna't see

Unless you have this mod on the side of your car: