Replacing o/e bushes is it generally true that induce vibration & harshness for a road car? Has anyone fitted them to their wishbones or arms & regretted it?
Upsides?
Tyres used to be x-ply and that dictated high sidealls, all giving a lot of deformation, flexibilty.
The Michelin puoneerde the radial tyre with the way more rigid circumferance and more liberty for the sidewall.
The upside of the radial was and is more directional satbility, the downside was and is more vibrations from the road surface transmitted to the car.
Manufacturers/designers were ´forced´ by consumer expectations of comfort to incorporate rubber somewhere in the suspension, trying to find a design compromise between rigidity (directional stability) and comfort (isolation from high frequency vibrations).
Lowering of the sidewall, increasing directional stability goes the same direction. Ditto the need for sóme rubber in the suspension.
Replacing rubbers by poly bushes is adding rigidity at the price of transmitting high frequency vibrations.
Now, although our Mk.3 is an over 20 year old design, remember that 50-55 section tyres are only half as high as wide.
Please do not mix older rubbers in the mix. That only confuses the matter.
Look at the engine mounts; old ones sag, get sloppy. Replacing them by new rubber restores the original compromise. Replacing them with poly is changing the design really.
Same thing suspension.
Imo good for race use only, ruining the car for the open road. That is however just my personal opinion.
All I can say is that the cars I have driven/been in with full hard polyurethane bushes have been quite "racecar". It's not the harshness but more the vibrations.
It does depend on which ones you replace with harder ones. Maybe it's more the solid engine mounts.
On other cars I've replaced the bushes with OE rubber and it's transformed the car. In fact I distinctly remember on my vx220 driving and thinking this feels so precise I don't know why people even make polybushes? Have you ever test driven a brand new sports car and thought you know what this needs, new bushes? Not me...
Car is very race car with them fitted.. I have fully poly bushed mine and and poly inserts in new front and rear engine mounts.
Car is super responsive, but yeah it rattles.. but it's used by myself 95% of the time as a commuter car and I have fun doing it..
Quote from: jvanzyl on February 23, 2020, 22:27Car is very race car with them fitted.. I have fully poly bushed mine and and poly inserts in new front and rear engine mounts.
Car is super responsive, but yeah it rattles.. but it's used by myself 95% of the time as a commuter car and I have fun doing it..
Did you do suspension or engine 1st?
Suspension wise - I have fitted poly bush and Coilovers at the same time. It went from a nice comfy car to a car that you would notice if you go over a penny on the road. At the end of the day its your choice but id not do it again if id be using it for a daily. Different ppl will tolerate things differently and if you can, try a car with suspension mods prior to spending your hard earned cash.
and keep in mind that stiffer, less conforming, is NOT quicker on the far from perfect real world surfaces.
Quote from: Nvy on February 24, 2020, 08:06Suspension wise - I have fitted poly bush and Coilovers at the same time. It went from a nice comfy car to a car that you would notice if you go over a penny on the road. At the end of the day its your choice but id not do it again if id be using it for a daily. Different ppl will tolerate things differently and if you can, try a car with suspension mods prior to spending your hard earned cash.
I won't have the opportunity to try a modded car. Like you I fitted the Meister. It's taken a while for them to bed in, but I've already bought Koni's. Have you kept your polybush suspension & what kind of shocks are you using now.
Quote from: Gaz mr-s on February 23, 2020, 22:43Quote from: jvanzyl on February 23, 2020, 22:27Car is very race car with them fitted.. I have fully poly bushed mine and and poly inserts in new front and rear engine mounts.
Car is super responsive, but yeah it rattles.. but it's used by myself 95% of the time as a commuter car and I have fun doing it..
Did you do suspension or engine 1st?
I did suspension first.
1 - did front strut brace
2 - did front polys
3 - later did rear polys
4 - put Matt TTE brace on
5 - then did coilovers with edfc
6 - replaced front and rear engine mounts with new ones and added poly inserts (they take about 50+ miles to bed in)
7 - at the time of #6 I put in a lightened flywheel, and the zero manifold.
8 - then putt snelbaards corky reproduction brace on.
The biggest differences I experienced was with #1 it was like night and day.
#2 made things harsher, but at the time I didn't know you could replace the front arms for £40...
#3 & #4 together made the car feel like a go kart, the garage loved it.
#3 completely removed any possible feeling of nervousness at high speeds.. (you know the one where your sphincter goes so tight it could resemble Gandalf saying "YOU SHALL NOT PASS!"
#3 drastically reduced wheel spin when pulling away.
#5 drastically reduced body roll, I could throw the car into corners more confidently, and i could switch between highway cruising and "race" and " there is no suspension" mode with a push of a button.
#5 finally exposed the weak point in the whole setup for corning which is the T1R's and their softer sidewall.. BUT I get punctures a fair bit, and have had to replace two rears so far... it's a much cheaper game.
#6 & #7 was interesting. The break in period of the inserts gave me a headache as combined with the lightened fly wheel I was ready to pack it all in when it came to traffic stop start. Having come through it, the lightened flywheel is a blast and my gear changes are than much exact due to the lack of engine movement. I do think replacing the side mounts will help the gear change with lateral g's as well.. But at the end of it all, the engine spools up so much quicker.
#8 was a big improvement on cabin rattle and ability to cope with bumps again. Highly recommend it.
Hope this helps...
In answer to your question, if you want to treat your road car like a race car then I'd say you could do it.
If you're more inclined to take the occasional corner a bit faster and otherwise enjoy cruising then I wouldn't.
What I WOULD recommend is replacing all bushes regardless of which route you take. The youngest cars will be going on 14 years now and the general rule of thumb is around 10 years or 100 000 miles before oem bushes start to deteriorate. Don't get me wrong, you can get away with knackered bushes for quite some time, but it's like being a slow boiled frog.
In terms of sources for OEM bushes for the rear, I'm not sure anyone has found and exact source..this is why people fall into the polybush route.
Where abouts are you based, you're very welcome to check my car out for how it feels before you make choice?
I would avoid poly bushing on a road car/occasional track car unless you dont mind it feeling like a race car with more vibration, noise and rattles and its awful!, just fit new oem bushings if worn.
Quote from: Gaz mr-s on February 24, 2020, 09:11I won't have the opportunity to try a modded car.
Then putting 3,5 bar in the tyres will be a good replication of the level of high frequency vibrations.
And if stability, or a perception of it, at speed is the issue; go for some aero mods. Those are cheap, have no draw backs and are surprisingly effective. If you have any doubt about the effectiveness of even minute changes, ask about Mongos....
You'd be OK with just wishbone and arm bushes with 60-70a bushes. I done this with my old Clio 182 track car and didn't notice much difference in noise and vibration. It's when you start adding them to engine/gearbox mounts that noise and vibration starts to appear.
My 2zz is fitted with them nose to tail and it's very load and you get crazy vibrations at certain idle rpms. All adds to the track car experience for me, but as a daily would become tiresome very quickly.
I do wonder sometimes about taking them out of the engine mounts... I'm just tired of crawling around under the car..
The one at the rear isn't too bad.. it's the one by the firewall that I'm not looking forward to.
oneday I'll get round to it.. I'll be well annoyed if the engine starts moving so much more that it affects the gear change badly, but it shouldn't as they're new mounts.. and at least I'd be able to say for definite if they're worth it.
Ok folks, thanks for your inputs. I've decided against going for them. They might be advertised on here later..??
Quote from: Gaz mr-s on February 24, 2020, 09:11Quote from: Nvy on February 24, 2020, 08:06Suspension wise - I have fitted poly bush and Coilovers at the same time. It went from a nice comfy car to a car that you would notice if you go over a penny on the road. At the end of the day its your choice but id not do it again if id be using it for a daily. Different ppl will tolerate things differently and if you can, try a car with suspension mods prior to spending your hard earned cash.
I won't have the opportunity to try a modded car. Like you I fitted the Meister. It's taken a while for them to bed in, but I've already bought Koni's. Have you kept your polybush suspension & what kind of shocks are you using now.
I have everything still fitted and I crashed because of my tired rubber bushes so I wont be going for rubbers anytime soon but like you ill have Koni's with refurbed TTE springs. Just to save up a bit more, will order them at the beginning of next month.
More on the crash - when I had the car I replaced everything you have to when buying 2nd hand car - oil, water pump, etc, etc. I had good tires and the 4 wheel alignment. What happened is when I drove in a rainy weather when I was changing gears the tail would try to catch the front. Once it got me and I over corrected so I ended in a ditch. Pretty happy that I didnt hit anybody and went out to tell. Now after the new bushes everything holds pretty good, I once went through a oil puddle and it was stable.
Quote from: Nvy on February 24, 2020, 13:31I have everything still fitted and I crashed because of my tired rubber bushes
...
when I was changing gears the tail would try to catch the front. Once it got me and I over corrected so I ended in a ditch.
Hmmm.... ;-)
Glad you are happy now, but néw rubbers would be just as safe.
Quote from: Petrus on February 24, 2020, 13:37Quote from: Nvy on February 24, 2020, 13:31I have everything still fitted and I crashed because of my tired rubber bushes
...
when I was changing gears the tail would try to catch the front. Once it got me and I over corrected so I ended in a ditch.
Hmmm.... ;-)
Glad you are happy now, but néw rubbers would be just as safe.
True but at least I wont be scared to drive. Its one thing to drive on the edge but another to be on the edge every time there are 2 drops of rain.
Quote from: Nvy on February 24, 2020, 13:48Quote from: Petrus on February 24, 2020, 13:37Quote from: Nvy on February 24, 2020, 13:31I have everything still fitted and I crashed because of my tired rubber bushes
...
when I was changing gears the tail would try to catch the front. Once it got me and I over corrected so I ended in a ditch.
Hmmm.... ;-)
Glad you are happy now, but néw rubbers would be just as safe.
True but at least I wont be scared to drive. Its one thing to drive on the edge but another to be on the edge every time there are 2 drops of rain.
I like that; ok to drive on the edge, not ok to be on the edge whilst driving
Going against the grain here, but my car is fitted with all the bushings from here:
https://www.polybush.co.uk/shop/toyota/mr2-roadster
I couldn't be happier with them. NVH has barely increased, and the car feels considerably more precise.
I would however, NEVER fit poly engine mounts to a road car. EVER.
The vibration is absolutely horrendous.
Anyone found a good source for (rubber) front ARB stabiliser bushes?
I ordered these on ebay...
https://www.ebay.co.uk/itm/2x-NEW-J72049YMT-YAMATO-FRONT-ANTI-ROLL-BAR-STABILISER-BUSH-KIT-I-OE-REPLACEMENT/352974577545
After another user on another post linked to them.
Rather annoyingly, they cancelled my order and refunded me saying they're no longer in stock.
And yet, they still list them as available on ebay when I check today.