Tasmin Trailing Arm Design Improvements
Discussion
Hi Wedgies,
As you all know I love a nice Wedge & all my Wedgie mates, so please take all this in the constructive way it's intended.
I was having a look under Solitudes 350i the other day and started to get a proper understanding of what's going on with his rear suspension.
Pretty quickly I came to the conclusion that even with perfect new trailing arm bushes the design is never going to give proper axle location.
From a fundamental engineering perspective the design just doesn't seem right to me, there's simply way too much leverage on that big squishy bush & it really doesn't help that the arm itself is so efin long.
Just looking at the design & moving the system with a pry bar left me in absolutely no doubt...
Replacing that big old squishy doughnut with a properly bracketed bush would transform the the handling of these fantastic & very underrated cars ;-)
If you have even the slightest imbalance in the rear wheel, a worn/loose wheel bearing or a shagged UJ it's going to be massively amplified with the current design, not to mention the impact on handling such poor axle location will generate.
So I did a bit of PH research on the Tasmin trailing arm set up, and it came as no surprise to me that you clever Wedgies identified this design weakness years ago & have developed some sensible modifications to solve it.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
One guy even describes the bronze bush mod I came up with while discussing the system with Solitude, others seemed to have employed a rose joint when they raced these cars.
So my question is...
"Is there a bush & bracket kit available to solve the trailing arm design weaknesses?"
In my opinion every trailing link Tasmin out there would benefit massively from such a mod.
If a kit is not available perhaps one of you clever Wedgie boys could fab up a copy of their solution and make it available to the community?
Can anyone help?
As you all know I love a nice Wedge & all my Wedgie mates, so please take all this in the constructive way it's intended.
I was having a look under Solitudes 350i the other day and started to get a proper understanding of what's going on with his rear suspension.
Pretty quickly I came to the conclusion that even with perfect new trailing arm bushes the design is never going to give proper axle location.
From a fundamental engineering perspective the design just doesn't seem right to me, there's simply way too much leverage on that big squishy bush & it really doesn't help that the arm itself is so efin long.
Just looking at the design & moving the system with a pry bar left me in absolutely no doubt...
Replacing that big old squishy doughnut with a properly bracketed bush would transform the the handling of these fantastic & very underrated cars ;-)
If you have even the slightest imbalance in the rear wheel, a worn/loose wheel bearing or a shagged UJ it's going to be massively amplified with the current design, not to mention the impact on handling such poor axle location will generate.
So I did a bit of PH research on the Tasmin trailing arm set up, and it came as no surprise to me that you clever Wedgies identified this design weakness years ago & have developed some sensible modifications to solve it.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
One guy even describes the bronze bush mod I came up with while discussing the system with Solitude, others seemed to have employed a rose joint when they raced these cars.
So my question is...
"Is there a bush & bracket kit available to solve the trailing arm design weaknesses?"
In my opinion every trailing link Tasmin out there would benefit massively from such a mod.
If a kit is not available perhaps one of you clever Wedgie boys could fab up a copy of their solution and make it available to the community?
Can anyone help?
Edited by ChimpofDarkness on Thursday 4th October 13:12
SporttiJanne said:
I fitted these polyurethane bushes instead of the original rubbers: http://superflex.co.uk/proddetail.php?prod=SF111-1...
Interesting, as a rule I'm not a huge fan of poly bushes but I'm open to it in this case.How are you finding them Jean?
Is the movement greatly reduced compared with the standard rubber ones?
How are they lasting?
How long/many mile have they been on?
Any excessive wear in the poly bush yet?
Sorry for all the questions, I'm just curious
Yep, get all that Ian, & I knew the history & origins already.
The important bit we shouldn't overlook within the history is both Lotus & TVR moved away from the design as quickly as they could.
This alone should tell us something, but all this was never meant to be about slagging off the Tasmin or upsetting my Wedgie mates.
I love Wedges, period.
Have a look at my intro, I was very careful to point this out right from the start, it's just all car design can be improved, lord knows I've spent nearly 4 years getting my Chimp as I want it, & it isn't over yet
Now all that's clear lets get real.
We can pretend the Tasmin semi trailing arm set up is a good design, but the fact is from an engineering perspective it simply isn't.
We could dream up all sorts of sliding drive shaft solutions, but lets be honest they aren't really practical or cost effective.
What I was hoping for from this post was some simple ideas that offer a measurable improvement on a budget.
So thanks to Steve Evans & Jean Niemi for their real world solutions
Big up the Wedgies
The important bit we shouldn't overlook within the history is both Lotus & TVR moved away from the design as quickly as they could.
This alone should tell us something, but all this was never meant to be about slagging off the Tasmin or upsetting my Wedgie mates.
I love Wedges, period.
Have a look at my intro, I was very careful to point this out right from the start, it's just all car design can be improved, lord knows I've spent nearly 4 years getting my Chimp as I want it, & it isn't over yet
Now all that's clear lets get real.
We can pretend the Tasmin semi trailing arm set up is a good design, but the fact is from an engineering perspective it simply isn't.
We could dream up all sorts of sliding drive shaft solutions, but lets be honest they aren't really practical or cost effective.
What I was hoping for from this post was some simple ideas that offer a measurable improvement on a budget.
So thanks to Steve Evans & Jean Niemi for their real world solutions
Big up the Wedgies
hallsie said:
Hey Big Chimp Man, why dont you mosey on over to the classifieds and have a look at the wedges for sale, go on, you know you want to!!
Ill do you a good deal!!
Stu
I'd love it, but my TVR funds are earmarked to give the Chimp a blow job..........Ill do you a good deal!!
Stu
Did I just say that
I'll explain............
Aiming for 350hp (300 at the boots) on LPG.
Already have the Canems dual fuel engine management system in place.
We already have GasWedge, soon you will have GasChimp
One day I'll get me a Wedge
SporttiJanne said:
I like them a lot!
The old rubber ones had some play on them and the car felt nervous when there were imperferctions on the road (even the painted road markings were easy to feel). Now the the ride is precise and smooth. Being a US-version the springs are not very hard, car feels very comfortable to drive. One might say: soft, but car steers where I want it to.
My car is standard Federal 280i model waiting for a fitting of a newly built 4 litre Cologne engine, so time will tell how well they cope the added power.
This summer I had two other TVR's on the road (Cerbera and 350i), so the mileage with this 280i was not much. But still, I am not expecting them to wear too much, as with my other cars that I have used SuperFlex bushes, the longest experience is a 400hp Cortina based Pilgrim Sumo kit car still on the same bushes fitted some 10 years ago.
See some shots of the 280i project: http://jannenr1.kuvat.fi/kuvat/Projektit/TVR+280i/
Perfect Jean, many thanks for answering all my questions.The old rubber ones had some play on them and the car felt nervous when there were imperferctions on the road (even the painted road markings were easy to feel). Now the the ride is precise and smooth. Being a US-version the springs are not very hard, car feels very comfortable to drive. One might say: soft, but car steers where I want it to.
My car is standard Federal 280i model waiting for a fitting of a newly built 4 litre Cologne engine, so time will tell how well they cope the added power.
This summer I had two other TVR's on the road (Cerbera and 350i), so the mileage with this 280i was not much. But still, I am not expecting them to wear too much, as with my other cars that I have used SuperFlex bushes, the longest experience is a 400hp Cortina based Pilgrim Sumo kit car still on the same bushes fitted some 10 years ago.
See some shots of the 280i project: http://jannenr1.kuvat.fi/kuvat/Projektit/TVR+280i/
Great photos too, I'll bookmark your link for future reference.
I also like Steve Evans's billet ally bush cage on the standard rubber bush.
Perhaps Steve's idea could be used on the SuperFlex poly bush for a completely fit & forget super well located solution?
I'm thinking a two part kit here.
Poly bush plus billet ally cage?
A complete DIY solution in one box, with no need to completely re-engineer the rear end of the car.
Edited by ChimpofDarkness on Friday 5th October 14:36
Wedg1e said:
ChimpofDarkness said:
real world solutions
If you want a proper engineered solution than you aren't going to find it in bodged-up brackets and a 'looks about right' approach; all you're doing is reducing the compromise(s) of the original setup. So when you've quite finished with the digs, carry on bodging.
If I want a car that handles well, I'll buy something other than a TVR. If I want to go really fast, I'll buy a (faster) bike.
I'm happy to live with my compromised TVR because... well phuckit, at the end of the day, does it really matter? It is what it is and it does what it does and my penis is quite large enough, thanks.
Yes.
Is that practical for the average Wedge owner that just wants to improve & enjoy his car on a realistic budget?
No.
"All you're doing is reducing the compromise(s) of the original setup"
Excellent, exactly what I was looking for
Believe it not, between the irrelevant worn out Chimp suspension point & bizarre penis reference we still ended up with some simple cheap ideas that should make an improvement on a compromised design.
I wouldn't call them "bodged-up brackets".
That would be disrespectful & rude to the nice people that were kind enough to add their constructive input.
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