Poly Exhaust Mount Kit - Any Feedback?
Discussion
I've also used poly exhaust bushes for a couple of years and they hold their shape much better especially as they are resistant to oil.
Please everyone keep sharing your techie experiences to keep Pistonheads valuable resource alive that’s been built up over the last 20 years.
RV8 - I'm doing my bit for Global warming
ChimpOnGas said:
I would never fit polyurethane suspension bushes but I have run polyurethane anti-roll bar bushes front and rear for over 7 years now and they have been perfect, even though they've seen a lot of oil over that time.
I'm a polyurethane fan now, but my suspension bushes will always remain metastatic with nylon thrust washers as they give great handling and excellent ride quality, polyurethane suspension bushes can in my experience give a harsh ride and I've even seen them melt too (upper wishbone bushes close to exhaust manifolds).
I’ve used Powerflex suspension bushes for 10 years and I’d be surprised if you would notice any difference, Powerflex suspension bushes for our cars now have nylon thrust washers like metastatic bushes and come with small heat reflective mats for the two directly under the exhaust manifolds.I'm a polyurethane fan now, but my suspension bushes will always remain metastatic with nylon thrust washers as they give great handling and excellent ride quality, polyurethane suspension bushes can in my experience give a harsh ride and I've even seen them melt too (upper wishbone bushes close to exhaust manifolds).
ChimpOnGas said:
Sadly its quite clear our precious TVR PH forum and information resource we've built together as a community is slowly dying, and thats very sad 
. Face Book being a key part of the problem, personally I remain committed to keeping PH alive by sharing information because on FB information is shared then lost to the wind in seconds.
Clearly the PH forum information resource is only as good as the constructive contributions freely made by the enthusiast who post, you'll always get the idiots who contribute nothing other than sarcastic comments but I bet they are searching for information and benefiting from it like us all, they are the leaches, but you find leaches in all walks of life so I guess it's to be expected... but never tolerated!
For the record I will continue to share my experiences even if that does mean answering by own post, I'm not embarrassed by that one bit because I genuinely believe the sharing of information is what being part of a community is all about.
I genuinely hope this post is helpful to someone, the rubber exhaust bobbins on our cars do get covered in oil and being rubber that means they do go soft, exhaust knocks and low tail pipes being the inevitable and extremely common consequence. If you go with these polly bobbins and hanger you fix that problem in a stroke, that's all I'm pointing out here so if it helps just one fellow enthusiast my work is done
I consider Facebook and Pistonheads as two different tools for two different jobs. Pistonheads with its individual threads per topic builds up a valuable resource of information that's perfect to refer back to, whereas Facebook is ideal for general social chat that’s rightly “lost to the wind in seconds” as you point out. For example comments “like meet you at the pub at 9:00“ or “I spotted a red one yesterday speeding towards...” deserves to be lost in the wind especially in this day and age with all the privacy issues.. Face Book being a key part of the problem, personally I remain committed to keeping PH alive by sharing information because on FB information is shared then lost to the wind in seconds.Clearly the PH forum information resource is only as good as the constructive contributions freely made by the enthusiast who post, you'll always get the idiots who contribute nothing other than sarcastic comments but I bet they are searching for information and benefiting from it like us all, they are the leaches, but you find leaches in all walks of life so I guess it's to be expected... but never tolerated!
For the record I will continue to share my experiences even if that does mean answering by own post, I'm not embarrassed by that one bit because I genuinely believe the sharing of information is what being part of a community is all about.
I genuinely hope this post is helpful to someone, the rubber exhaust bobbins on our cars do get covered in oil and being rubber that means they do go soft, exhaust knocks and low tail pipes being the inevitable and extremely common consequence. If you go with these polly bobbins and hanger you fix that problem in a stroke, that's all I'm pointing out here so if it helps just one fellow enthusiast my work is done
Please everyone keep sharing your techie experiences to keep Pistonheads valuable resource alive that’s been built up over the last 20 years.
RV8 - I'm doing my bit for Global warming
stevesprint said:
I’ve used Powerflex suspension bushes for 10 years and I’d be surprised if you would notice any difference, Powerflex suspension bushes for our cars now have nylon thrust washers like metastatic bushes and come with small heat reflective mats for the two directly under the exhaust manifolds.
I think the debate over polyurethane vs metalastic suspension bushes will rage on forever, personally I'm a metalastic fan because nothing isolates high frequency vibration better than rubber which is why it remains the go to suspension bush material still universally used by all car makers to this day.My theory is if the big car makers wanted to switch to polyurethane they would have done so a very long time ago, there's clearly very good reason why they all universally still use rubber. And I'm not just talking about soft everyday cars, Porsche, Aston Martin, Ferrari, Lamborghini have all stuck with rubber bushes when they easily could have switched to polyurethane, even smaller makers of more hard edged sports cars like Lotus have remained committed to the venerable old rubber suspension bush.
I was also warned off polyurethane suspension bushes by a host of well respected TVR specialists, when people like Jason Clegg from Str8ght Six and Mat Smith advises you against them you have to listen, these people are hugely experienced having the benefit of up close intimate experience working on literally thousands of TVRs. These guys will have seen hundreds of cars with polyurethane suspension bushes through their doors, they also very likely fitted them themselves early on before forming their opinion.
With all this in mind and the fact I want my TVR to be a compliant great handling road car not a stiffened up hard as nails ride track focused weapon I decided a long time ago to stick with metalastic bushes, actually if you study a Chimaera metalastic suspension bush there isn't a great deal of rubber in them, I just can't see them promoting any meaningful deflection even under severe loading, what the rubber will do however is isolate high frequency noise, harshness, and vibration (NHV) better than any polyurethane bush will.
Finally on the subject of longevity you could argue the case either way, while metalastic bushes do wear out polyurethane bushes are themselves not completely immune to wear and there's always the well documented melting issue, I'm not sure I'd want to use a bush that needs to be wrapped with a bit of heat reflective material to survive. It's hardly a quality engineering solution now is it, to me the melting issue and the need for a section of heat reflective material to protect them just raises a clear question over the fundamental suitability of polyurethane as a bush material in areas where they run close to the exhaust manifolds.
Over the ten years I've owned my TVR I've driven tens of thousands of miles in the car and paid properly experienced TVR specialist to conduct three full geometry check had adjust sessions, basically the car enjoys this important maintenance work every three three years on average.Twice this work was completed by Str8ght Six and once recently by Mat Smith, as part of this work the experienced TVR specialist also checks for wear in all my metalastic suspension bushes.
So in all those miles over all those years how many metalastic suspension bushes do you think I've needed to have replaced?
Well the current attrition rate stands at just four worn metalastic suspension bushes that demanded replacement, the new metalastic bushes were cheap to buy themselves and it was not expensive to have the TVR specialist remove the old worn bush or bushes and fit new replacements before they concluded the work with a full geometry adjust and setup.
If I compare what I've paid to have these four metalastic bushes replaced with what it would have cost to fully polyurethane bush the car it becomes quite clear I could keep replacing the odd metalatic bush every three years for the next 10 years before I'd even come close to the cost of fully polyurethane bushing the car.
For all the above reasons I'm sticking with my genuine OEM TVR metalastic suspension bushes, I have fitted polyurethane ARB mounts, diff bushes and now a polyurethane exhaust mounting kit so I'm not entirely anti polyurethane bush, it's just I genuinely believe metalatic suspension bushes are a better choice for me and my needs than polyurethane ones.
This is of course just my personal opinion, others may choose to disagree
Sardonicus said:
As much as I prefer the metalastic variety and mine are still going strong 
anyone that states poly bushes give a noticeable harsher ride is talking b
ks with these cars 
the bushes are in pivot positions only for starters
Perhaps its because people fit poly bushes at the same time as fitting rose jointed track day suspension Simon, and sometimes also in conjunction with bigger wheels and low profile tyres which can make the ride even worse? anyone that states poly bushes give a noticeable harsher ride is talking bks with these cars the bushes are in pivot positions only for starters 
Perhaps it's these so called upgrades done at the same time as poly bushing the car that are the real reason the car became crashy?
However, I remain in the metalastic suspension bush camp and for all the reasons I've already covered, I'm also in the rubber bushed coil over camp which is why I went back to Bilsteins. I also like a decent bit of tyre wall height on my TVR, pneumatic tyres were a game changing invention so on the road all this trend towards low profile tyres on a road going TVR with less and less air in them is just wrong.
Modern cars have far far superior suspension than a TVR Chimaera so modern cars can often get away with lower profile tyres that would massively upset a TVR. The uncomfortable truth for us all is a modern Ford Fiesta, Polo or the like is actually often much faster than the far more powerful TVR when scratching on the back roads, a good example of this was when I had a Prius, yes I had one (well three actually).
People can take the pish but one day I was being followed by my mate in his mighty five litre Chimaera, I decided to nail it in the Prius on a nice winding road and absolutely left the TVR for dead, he was trying but I was way faster, on entry the Prius brakes scrubbed off speed insanely well and the suspension helped greatly here too, I could stand on the brakes safe in the knowledge the ABS and traction control were there to save me while my mate in the TVR needed to be a lot more cautious, the Prius then absolutely annihilated the TVR in the bends to the extent it simply wasn't a contest.
Its a painful story none of us want to read but its also 100% true, my point is things have moved on, the Prius suspension and geometry was so much better than the TVR the Toyota could wear low profile tyres without the ride become painful, in turn you could actually enjoy the benefits of the stiffer side walls. You could never fit such tyre to a Chimaera without expecting it to become a really nasty crashy experience that actually handled worse.
Back to my TVR I want my suspension to actually suspend, I also want my tyres to be part of the suspension system just as the designer intended. I've had rose jointed Gaz Gold Pros in the past and they we're not for me, I need the car to ride nicely and handle well, and I absolutely reject the idea that these two expectations should be in conflict with each other. Quite the opposite in fact, because without any shadow of a doubt I can 100% grantee you all on UK roads were we must often suffer terrible broken surfaces my TVR Chimaera on big rubber bush Mk4 Tuscan S spec Bilsteins is now a country mile faster and better handling than it was on rose jointed and much firmer damped/sprung Gaz Gold Pros.
Its all about the better Bilstein suspension soaking up the bumps rather than crashing into or skipping over them as with the GGPs, as we should all know the design objective for suspension is for the trye to remain in contact with the road for as much time as is physically possible. This is because a tyre in the air and so not in contact with the road (even for a split second) offers no grip whatsoever, and there's absolutely no question my Mk4 Tuscan S spec Bilsteins do a way way better job of keeping my tyres in contact with the road than my Gaz Gold Pros did.
As Colin Chapman taught us some 60 years ago when he developed the 'Chapman Strut', suspension should suspend and almost always a longer travel and better damped suspension unit will make the car far faster than a rock hard setup. We can still see this principle used to great effect by Lotus today, just take a ride in an Evora and you'll soon see what I mean
ChimpOnGas said:
Perhaps its because people fit poly bushes at the same time as fitting rose jointed track day suspension Simon, and sometimes also in conjunction with bigger wheels and low profile tyres which can make the ride even worse?
Perhaps it's these so called upgrades done at the same time as poly bushing the car that are the real reason the car became crashy?
This ^ Perhaps it's these so called upgrades done at the same time as poly bushing the car that are the real reason the car became crashy?
lancelin said:
Interesting, that picture from Stevesprint shows the top left bush is deformed where it hits the top of the plate!!!! its possible exhaust heat has caused it or the bolt has been over tightened! bit of a worry if its a heat problem.
Your right and its a worry, probably a combination of being too close to the exhaust and I remember re-tightening them mid-summer when I had an annoying rattle that turned out to be something else but interestingly they were very loose again.You can see the poly is dangerously close and fried
The other side and rear are ok.
Despite the above Powerflex’s suspension bushes are still a no brainer for me for the following reasons.
1. Life time warranty https://www.powerflex.co.uk/lifetime_warranty.php
2. Installation & removal without a press or hacksaw
3. My top suspension poly bushes are still perfect without the heat shields and I know because I’ve had my front suspension arms off this winter for powdering coating.
Furthermore I’m currently faced with the fun challenge of cutting out my rear diff metalastic bush in the chassis and once removed I will never install a metalastic bush.
COG
I respect your points regarding suspension bushes so please lets just agree to differ and hope we can still be friends
stevesprint said:
Your right and its a worry, probably a combination of being too close to the exhaust and I remember re-tightening them mid-summer when I had an annoying rattle that turned out to be something else but interestingly they were very loose again.
You can see the poly is dangerously close and fried
Hmmm, poly and heat are definitely not happy bedfellows, I'll keep an eye on mine You can see the poly is dangerously close and fried
Still look way better than these though
.....
So I'm happy the poly exhaust bobbins were the right choice on my oily gas bag
stevesprint said:
COG I respect your points regarding suspension bushes so please lets just agree to differ and hope we can still be friends
I just can't see our relationship ever recovering from this poly vs metalastic suspension bush debate Steve, I think its best we never speak again 
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