Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB
Page 1 of 2 1 2
Show 40 post(s) from this thread on one page

Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB (https://www.ft86club.com/forums/index.php)
-   Suspension | Chassis | Brakes -- Sponsored by 949 Racing (https://www.ft86club.com/forums/forumdisplay.php?f=59)
-   -   Rear end hop (https://www.ft86club.com/forums/showthread.php?t=66846)

sprintamx 05-28-2014 07:51 PM
Rear end hop
 
Anyone experience the rear end skipping sideways over bumps under acceleration, or just a relatively "large" bump and moderate throttle? If so, any solutions other than struts and springs? I'm wondering whether stiffer bushings, mounts, LCAs, etc. will keep the rear planted.


Thanks.

ramiram1984 05-28-2014 07:54 PM
the miata was worse...had a 95.

MyEvilMonkeys 05-28-2014 08:25 PM
The coilovers didn't seem to make that much of a difference. I feel the sub-frame bushings may have helped some. Any mods or completely stock?

NLSP 05-28-2014 08:40 PM
Subscribed.

I'm hoping Whiteline's rear sub-frame bushing inserts will help alleviate that.

Nevermore 05-28-2014 08:43 PM
A lot of the roads I commute on are in pretty rough shape, and it always seems to be in the turns. I hate that sensation of bouncing along around when I turn, makes the car feel unbalanced. It seems dangerous too. I'd love a solution for it.

Turdinator 05-28-2014 11:25 PM
I suspect it is more due to the lack of rear suspension travel that people talk about. If you are willing to experiment you could trim you rear bumpstops down and see if that helps.

NissanGuy 05-28-2014 11:38 PM
I bet it's the ultra soft bushings deflecting violently. When I did the Whiteline subframe inserts it helped a bit.

I believe the rest of the skipping around comes from the differential bushings. I hope to do the whiteline diff insert bushings eventually.

gramicci101 05-28-2014 11:48 PM
The Whiteline diff carrier inserts make a huge difference. You can see how much they deflect in the video on FT-86SF's positive traction kit page. Even though the page is for different bushings. http://ft86speedfactory.com/whitelin...n-kit-287.html

They're an easy install, you just need to make sure the diff is supported when you pull the front two bolts.

radroach 05-29-2014 12:06 AM
I feel the car hop around when I go around corners, if my rear tires go over a bump in a corner it will sometimes want to slide out and TC will come on.

NissanGuy 05-29-2014 12:21 AM
Quote:
Originally Posted by gramicci101 (Post 1765335)
The Whiteline diff carrier inserts make a huge difference. You can see how much they deflect in the video on FT-86SF's positive traction kit page. Even though the page is for different bushings. http://ft86speedfactory.com/whitelin...n-kit-287.html

They're an easy install, you just need to make sure the diff is supported when you pull the front two bolts.
That video was what sold me the subframe bushing inserts. Subframes should NOT move around! I work on MINIs for a living, and none of the current cars even have subframe bushings. That's why they handle so well. That, and very nice shocks.

I wish I could find a similar video for the diff bushings, I absoluetly hate the jiggling feeling when going over bumps. Is it completely gone with the inserts installed?

gramicci101 05-29-2014 12:28 AM
Honestly, that video sold me more on the diff carrier inserts than the subframe inserts. I couldn't really see the subframe flexing on its bushings, but the diff carrier was bouncing around like crazy.

The polyurethane itself is very slightly flexible, but not very compressible. There are the two big bushing inserts on the back of the carrier and two smaller sets of collars/inserts for the front of the diff. It's an easy install. Once they're all in, there's a noticeable difference. There's no *thunk* from the rear end when you shift hard and get on the gas. A lot of the slop in the drivetrain has been removed. It's definitely worth the money.

sprintamx 05-29-2014 11:43 AM
Quote:
Originally Posted by MyEvilMonkeys (Post 1764995)
The coilovers didn't seem to make that much of a difference. I feel the sub-frame bushings may have helped some. Any mods or completely stock?
I've installed full Ground Contorl Koni coilovers; 375 lb springs front, 350 lbs rear. Rear shocks are at their lowest/softest setting. I experienced rear hop on the stock suspension and tires, which I reduced a bit with moving to Michelin PSS2s (softer tire). I have had the Konis at a stiffer setting in the rear and still experienced the hop.

sprintamx 05-29-2014 11:49 AM
Quote:
Originally Posted by Turdinator (Post 1765297)
I suspect it is more due to the lack of rear suspension travel that people talk about. If you are willing to experiment you could trim you rear bumpstops down and see if that helps.
When I installed the GC Konis I lowered the rear height 1 1/8 inch (sorry, no metric measurements) and the fronts 1 1/4. All the strut assemblies came with GC bump stops that I "believe" have a lower profile (are shorter) than stock. I would say that I maintained "adequate" travel with the setup, but maybe not?

I do plan on calling GC for some guidance, but I think we're starting to develop a little knowledge base that subframe and diff bushings/mounts are an integral part of this movement; which makes sense.

sprintamx 05-29-2014 11:53 AM
Quote:
Originally Posted by gramicci101 (Post 1765406)
Honestly, that video sold me more on the diff carrier inserts than the subframe inserts. I couldn't really see the subframe flexing on its bushings, but the diff carrier was bouncing around like crazy.

The polyurethane itself is very slightly flexible, but not very compressible. There are the two big bushing inserts on the back of the carrier and two smaller sets of collars/inserts for the front of the diff. It's an easy install. Once they're all in, there's a noticeable difference. There's no *thunk* from the rear end when you shift hard and get on the gas. A lot of the slop in the drivetrain has been removed. It's definitely worth the money.
This describes some of the particular effects I feel when the rear is "displaced": slop in the drivetrain. There's only so much I can ask shocks, springs and a sway to do if the diff isn't well isolated and/or the subframe has too much movement.


All times are GMT -4. The time now is 04:49 AM.
Page 1 of 2 1 2
Show 40 post(s) from this thread on one page

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2026, vBulletin Solutions Inc.
User Alert System provided by Advanced User Tagging v3.3.0 (Lite) - vBulletin Mods & Addons Copyright © 2026 DragonByte Technologies Ltd.


Garage vBulletin Plugins by Drive Thru Online, Inc.