Poly Exhaust Mount Kit - Any Feedback?

[ChimpOnGas]

Checking the car over at the weekend it looks like my old rubber exhaust mountings are shot, they've gone soft!

While I'm typically a metalistic bush man when it comes to wishbones, diff mounts, ect... I have fitted poly bushes on my ARB which seem to work fine. I'm now tempted to try poly on the exhaust as I see you can buy undertray mounting bobbins and the hanger bush in and poly, so I'm thinking as these will be unaffected by oil like rubber they may be worth a try?

Is anyone using poly on their Chimaera exhaust, if so what is your opinion, my concern is they may cause squeaks and allow more vibration into the car?

Here's what I'm considering...





Or am I better off just sticking with good old fashioned rubber?

[ChimpOnGas]

I'll answer my own question then

The above polly exhaust mounting kit works really well, unlike rubber that swells and splits polyurethane is completely impervious to oil.

I can also confirm they do not promote squeaks, they are completely silent in fact.

https://www.outlawmotorsport.co.uk/product-page/tv...

And....

https://www.outlawmotorsport.co.uk/product-page/tv...

Outlaw Motorsport offer lots of colour choice, but being a conservative chap I just went with black.

Recommended

[ChimpOnGas]

Classic Chim said:

Only time heat and miles will tell.
I replaced my rubber ones and it only took about a year before they were looking very second hand so you can’t loose much.

Four months fitted and 3,000 miles covered they seem spot on so far Alun, there's also no argument rubber swells and splits, compared with rubber polyurethane is known to be very long lasting and is of course completely impervious to oil.

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.

Along with my 7 year old polyurethane ARB bushes I now have polyurethane diff bushes and the polyurethane exhaust mounting kit we're discussing here so I'm confident they will last at least as long as my ARB bushes have which actually still look new. For the listed areas but not suspension bushes where I've stuck with metastatic, polyurethane looks to be the ideal material especially where there's oil and other contaminants present.

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).

1. Anti-roll bar bushes = Polyurethane

2. Diff bushes = Polyurethane

3. Exhaust mounting bobbins and hanger = Polyurethane

4. Suspension bushes = Metastatic with nylon thrust washers

5. And a set of Ben Lang's excellent Mk4 Tuscan 'S' spec big bush Bilsteins to complete the job

[ChimpOnGas]

phazed said:

Dave, we must do a back to back someday as my car is full poly and it would be very interesting to see if there is much of a difference.

Apart from.......my rubber exhaust bobbins.

Thanks for the heads up, I'll order a set now.

It’s the Bicester Heritage Sunday scramble tomorrow Peter, I’ll be there from 9.00am if you fancy it?

[ChimpOnGas]

phazed said:

ChimpOnGas said:

It’s the Bicester Heritage Sunday scramble tomorrow Peter, I’ll be there from 9.00am if you fancy it?

Defo not! I've other problems to sort first..........

I'll sort a late spring/early summer bbq...with a bit of driving.

BBQ sounds great

Hope you get your other problems sorted, shout if you need any help mate?

D.

[ChimpOnGas]

Jobster said:

motul1974 said:

Is replying to your own post a first on here I wonder????

...thanks for the replying, I looked at these before but just went back to rubber.

And such a short answer to his own post too. Remarkable....

For the avoidance of any doubt, I've answered my own post in the spirit of sharing information.

I do so in the hope it may be of help to the community, this is the foundation concept behind all the PH forums and is especially true of the TVR forums where decent right minded enthusiasts freely share information in the hope it may help their fellow TVR enthusiasts in some way.

Rightly of wrongly this has always been my approach to Piston Heads, so feel free to ridicule me for that .

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

[ChimpOnGas]

A friends discovery today, mine were the same if not worse, totally shot!

This is what happens to the rubber bobins when oil gets on them, the polly ones completely solve this problem so are well worth considering.

[ChimpOnGas]

phazed said:

Fitted them today.

Test drove car and all good.

Looks good Peter

I'm assuming you went with blue because its faster

[ChimpOnGas]

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

[ChimpOnGas]

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 bks 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?

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]

Over tightened surely

Sorry Steve

[ChimpOnGas]

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

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

[ChimpOnGas]

lancelin said:

Thanks for publishing my pic Dave! :-) A result of oil damage and being tightened up too tight.