Hypothetical Question...
Discussion
Some of you may know the history of my car, some not. You could probably find the story on here still if you want the full details.
Anyway, put simply, I ended up with a T350T when I originally ordered a C. It was my choice, I got some sweetners from the factory, I love my car. Can't complain really.
However, the ongoing issue with wind noise from the panels prompted me to ask at the factory a million dollar question;
Is it possible to convert a T back to a C?
Looking at the difference I don't see what the big deal would be. Obviously it would be fairly costly (or would it?) and fiddly but I can't see that there would be that much compromise in the structural rigidity of the car seeing as it gets that from the roll cage (correct me if I'm wrong). So, by my reckoning you'd do this;
1 - remove the central bar
2 - fill the hole in (its only fibre-glass and glue so it can't be that hard)
3 - sand it down
4 - paint it
5 - upholster the inside
6 - job done
I know i'm being simplistic but imagine this hypothetical situation - you're driving along and a heavy object, say a brick, falls off the back of a lorry and lands on your roof, making a right mess. Surely (a) it wouldn't be a right-off and (b) factory wouldn't build you a totally new body shell? They'd just patch up your roof wouldn't they?
I imagine you can guess the factory's answer? Put it this way, it was preceeded by a sharp intake of breath....but then they would say that I suppose...
Discuss....
Anyway, put simply, I ended up with a T350T when I originally ordered a C. It was my choice, I got some sweetners from the factory, I love my car. Can't complain really.
However, the ongoing issue with wind noise from the panels prompted me to ask at the factory a million dollar question;
Is it possible to convert a T back to a C?
Looking at the difference I don't see what the big deal would be. Obviously it would be fairly costly (or would it?) and fiddly but I can't see that there would be that much compromise in the structural rigidity of the car seeing as it gets that from the roll cage (correct me if I'm wrong). So, by my reckoning you'd do this;
1 - remove the central bar
2 - fill the hole in (its only fibre-glass and glue so it can't be that hard)
3 - sand it down
4 - paint it
5 - upholster the inside
6 - job done
I know i'm being simplistic but imagine this hypothetical situation - you're driving along and a heavy object, say a brick, falls off the back of a lorry and lands on your roof, making a right mess. Surely (a) it wouldn't be a right-off and (b) factory wouldn't build you a totally new body shell? They'd just patch up your roof wouldn't they?
I imagine you can guess the factory's answer? Put it this way, it was preceeded by a sharp intake of breath....but then they would say that I suppose...
Discuss....
Hi Neil,
I take it they never improved the wind noise problem when the car went back to the factory.I have never really noticed a big problem with my panels,in fact their is no noise at all on the passenger side,drivers side no noise until 90+mph.
Have you tried another set of panels?
If not try mine when i get the car back,wait till the summer,you'll be glad you,ve got the T
Rob
I take it they never improved the wind noise problem when the car went back to the factory.I have never really noticed a big problem with my panels,in fact their is no noise at all on the passenger side,drivers side no noise until 90+mph.
Have you tried another set of panels?
If not try mine when i get the car back,wait till the summer,you'll be glad you,ve got the T
Rob
Evening Rob!
No, they just really held up their hands and said there wasn't much they could do with the current design (or the new one either apparently, but that's another story, and wasn't offered as a solution anyway)
I'm not hating the car because of the panels and, as you said, I've yet to drive it a lot in the good weather with them off (really looking forward to Eurohoon with the top off in fact). Its just that I don't feel comfortable in the car when "giving it plenty of right foot" - I find the noise very distracting and I find myself backing off as I can't stand sustaining high speeds with the equivalent of a high pressure air line in my ear.
Perhaps, on balance, the summer experience will convince me otherwise. But I do still, in all honesty, prefer the look of the C, plus you don't get the noise. My mood varies from day to day
No, they just really held up their hands and said there wasn't much they could do with the current design (or the new one either apparently, but that's another story, and wasn't offered as a solution anyway)
I'm not hating the car because of the panels and, as you said, I've yet to drive it a lot in the good weather with them off (really looking forward to Eurohoon with the top off in fact). Its just that I don't feel comfortable in the car when "giving it plenty of right foot" - I find the noise very distracting and I find myself backing off as I can't stand sustaining high speeds with the equivalent of a high pressure air line in my ear.
Perhaps, on balance, the summer experience will convince me otherwise. But I do still, in all honesty, prefer the look of the C, plus you don't get the noise. My mood varies from day to day
Exactly. I do want to discuss it with them sensibly and intend to do so but I want to be armed with some knowledge or ideas to put forward.
But don't misunderstand - the reason for posting on here was not to rubbish them. My idea was that, as there are plenty of people on here with a wide variety of experience, I'm hoping (seeing as the factory, by their own admission, are stumped as to how to solve the problem) some bright spark might come up with a good suggestion about a solution.
To me, the only real way of fixing it is to not have the panels - hence my radical question.
But don't misunderstand - the reason for posting on here was not to rubbish them. My idea was that, as there are plenty of people on here with a wide variety of experience, I'm hoping (seeing as the factory, by their own admission, are stumped as to how to solve the problem) some bright spark might come up with a good suggestion about a solution.
To me, the only real way of fixing it is to not have the panels - hence my radical question.
Just a thought here ... but just do both if you want less wind noise and an open roof! I'm thinking of making the "holes" in the roof smaller and fitting two of those old tilting glass roofs longitudinally.
Fibreglass and epoxy, sanding and painting can be easily done after some practice with a mould (in dry conditions!).
About the glass roofs, they should be manually (weight) tilting only, as sliding will give the car wings like the Looney Tunes Tuscan S.
(Just keep the roofs closed at high speed and there shouldn't be a problem of taking off.)
Hope that was one of those bright ideas. Now, you just got yourself two extra surfboards.
Edited to let you know I have experience with fibreglass, carbon and kevlar fibres for surfboards and sailing boats, so you can trust me on it being doable! ... Maybe you can ask the factory for (a copy of)the moulds of the roof of the T350C?
Good luck!
>> Edited by Waveboy14 on Thursday 25th March 01:05
Fibreglass and epoxy, sanding and painting can be easily done after some practice with a mould (in dry conditions!).
About the glass roofs, they should be manually (weight) tilting only, as sliding will give the car wings like the Looney Tunes Tuscan S.
(Just keep the roofs closed at high speed and there shouldn't be a problem of taking off.) Hope that was one of those bright ideas. Now, you just got yourself two extra surfboards.
Edited to let you know I have experience with fibreglass, carbon and kevlar fibres for surfboards and sailing boats, so you can trust me on it being doable! ... Maybe you can ask the factory for (a copy of)the moulds of the roof of the T350C?
Good luck!
>> Edited by Waveboy14 on Thursday 25th March 01:05
Neil
As you have previously helped me, and I am away on business in San Francisco and nothing to do tonight, as I am regular traveler here, I have dedicated my evening to finding you a solution!
From what I can tell there is a solution. It’s basically a noise canceling system, similar to that used by Bose in their headphones (I can assure you they definitely work). It involves your car stereo and microphones. As far as I can tell Honda's Japanese division have fitted it some cars. Honda's system actually analysis’s the stereo music source and then the noise in the car and then uses white noise to combat/cancel the background noises, so with nothing playing it still cancels the noise. Ironically I am off to Tokyo next week so I will get my Japanese staff to phone them if you want as they know I am a car nut and already think I am mad! In the meantime I have found some links that may help:
www.school-for-champions.com/science/noise.htm
www.ece.ucdavis.edu/~hurst/papers/Le%2CJSSC02.pdf
www.halfbakery.com/idea/Noise-canceling_20car_20stereo
One thing they do all state though is wind noise is hard to cancel but your brain effectively cancels noise itself after about 1 minute.
regards
Simon
>> Edited by maddog[uk] on Thursday 25th March 05:22
As you have previously helped me, and I am away on business in San Francisco and nothing to do tonight, as I am regular traveler here, I have dedicated my evening to finding you a solution!
From what I can tell there is a solution. It’s basically a noise canceling system, similar to that used by Bose in their headphones (I can assure you they definitely work). It involves your car stereo and microphones. As far as I can tell Honda's Japanese division have fitted it some cars. Honda's system actually analysis’s the stereo music source and then the noise in the car and then uses white noise to combat/cancel the background noises, so with nothing playing it still cancels the noise. Ironically I am off to Tokyo next week so I will get my Japanese staff to phone them if you want as they know I am a car nut and already think I am mad! In the meantime I have found some links that may help:
www.school-for-champions.com/science/noise.htm
www.ece.ucdavis.edu/~hurst/papers/Le%2CJSSC02.pdf
www.halfbakery.com/idea/Noise-canceling_20car_20stereo
One thing they do all state though is wind noise is hard to cancel but your brain effectively cancels noise itself after about 1 minute.
regards
Simon
>> Edited by maddog[uk] on Thursday 25th March 05:22
Hi Neil,
I have a T on order for May delivery and although I will be getting the mk 2 roof design I am still concerned about the wind noise issue.
I, and my dealer, have spoken to the factory about this
and the feeling is that the wind noise with the Mk 2 is not air getting into the car but simply the flow of air across the panels- at least at high speed. If this is the case then it will be very difficult to eradicate
Nonetheless I will be talking to the `factory´ about this whenI am up there in April to see my car in build.
Maybe this Japanese idea of cancelling out the noise is a possibility?
I have a T on order for May delivery and although I will be getting the mk 2 roof design I am still concerned about the wind noise issue.
I, and my dealer, have spoken to the factory about this
and the feeling is that the wind noise with the Mk 2 is not air getting into the car but simply the flow of air across the panels- at least at high speed. If this is the case then it will be very difficult to eradicate
Nonetheless I will be talking to the `factory´ about this whenI am up there in April to see my car in build.
Maybe this Japanese idea of cancelling out the noise is a possibility?
The noise is coming from the longitudinal flow down the side of the panels. No air appears to get into the interior of the car. If this was the case then driving in the rain at the sort of speeds that produce the wind noise would mean water finding its way through the seals. This does not happen.
The air flow needs to be disturbed to change the direction it flows over the roof and along the sides of the panels. Try the "open the window an inch" experiment and you can immediately notice the drop in wind noise (yes you get noise from the open window but that is markedly different).
I think the answer lies in the type of seals they are using. Mine I guess are the early type, with a very thin rubber flange around the external edges, with the compression "O" rubber around the underneath edge. I think that if they were re-designed using a wedge shaped external rubber of stiffer construction and maybe 10-15mm in width. I'm sure this would if the rubber is stiff enough, resist lifting and therefore decrease the wind noise.
I've tried - don't laugh... I had to do this in the dark!! - "sealing" the long edges of the panels with the fluorescent yellow masking tape from B&Q and the noise almost totally disappears. So the cause seems to
have been identified in my case.
A different seal could probably be retrofitted so costs are minimal......
The ultimate cure though is good weather and taking the roof off!
Ian
The air flow needs to be disturbed to change the direction it flows over the roof and along the sides of the panels. Try the "open the window an inch" experiment and you can immediately notice the drop in wind noise (yes you get noise from the open window but that is markedly different).
I think the answer lies in the type of seals they are using. Mine I guess are the early type, with a very thin rubber flange around the external edges, with the compression "O" rubber around the underneath edge. I think that if they were re-designed using a wedge shaped external rubber of stiffer construction and maybe 10-15mm in width. I'm sure this would if the rubber is stiff enough, resist lifting and therefore decrease the wind noise.
I've tried - don't laugh... I had to do this in the dark!! - "sealing" the long edges of the panels with the fluorescent yellow masking tape from B&Q and the noise almost totally disappears. So the cause seems to
have been identified in my case.
A different seal could probably be retrofitted so costs are minimal......
The ultimate cure though is good weather and taking the roof off!
Ian
Hello `999´
as I mentioned earlier I will be taking delivery of my T350T Red Rose with Mk 2 roof design in May 2004. I read your comments with interest. According to the factory the road test of the T350T (against Z4 I believe), where the reviewer complained about wind noise was a MK2 roof. I think you are right that the noise has to be to a large extent coming from the external seal not doing it´s job correctly. This could lie on the type of seal as you say and also individual cars-the bodywork and roof panel interface will vary from car to car I am certain. If there is too much variation in the gap bewteen bodywork and roof panel interface then I guess the job of the seal will be made even more difficult. I am sure that there is a degree of fine tuning that can be done on each car.
Look forward to hearing the results of your investigations.
as I mentioned earlier I will be taking delivery of my T350T Red Rose with Mk 2 roof design in May 2004. I read your comments with interest. According to the factory the road test of the T350T (against Z4 I believe), where the reviewer complained about wind noise was a MK2 roof. I think you are right that the noise has to be to a large extent coming from the external seal not doing it´s job correctly. This could lie on the type of seal as you say and also individual cars-the bodywork and roof panel interface will vary from car to car I am certain. If there is too much variation in the gap bewteen bodywork and roof panel interface then I guess the job of the seal will be made even more difficult. I am sure that there is a degree of fine tuning that can be done on each car.
Look forward to hearing the results of your investigations.
Hello `999´
as I mentioned earlier I will be taking delivery of my T350T Red Rose with Mk 2 roof design in May 2004. I read your comments with interest. According to the factory the road test of the T350T (against Z4 I believe), where the reviewer complained about wind noise was a MK2 roof. I think you are right that the noise has to be to a large extent coming from the external seal not doing it´s job correctly. This could lie on the type of seal as you say and also individual cars-the bodywork and roof panel interface will vary from car to car I am certain. If there is too much variation in the gap bewteen bodywork and roof panel interface then I guess the job of the seal will be made even more difficult. I am sure that there is a degree of fine tuning that can be done on each car.
Look forward to hearing the results of your investigations.
as I mentioned earlier I will be taking delivery of my T350T Red Rose with Mk 2 roof design in May 2004. I read your comments with interest. According to the factory the road test of the T350T (against Z4 I believe), where the reviewer complained about wind noise was a MK2 roof. I think you are right that the noise has to be to a large extent coming from the external seal not doing it´s job correctly. This could lie on the type of seal as you say and also individual cars-the bodywork and roof panel interface will vary from car to car I am certain. If there is too much variation in the gap bewteen bodywork and roof panel interface then I guess the job of the seal will be made even more difficult. I am sure that there is a degree of fine tuning that can be done on each car.
Look forward to hearing the results of your investigations.
grigio alloy said:
Hello `999´
as I mentioned earlier I will be taking delivery of my T350T Red Rose with Mk 2 roof design in May 2004. I read your comments with interest. According to the factory the road test of the T350T (against Z4 I believe), where the reviewer complained about wind noise was a MK2 roof. I think you are right that the noise has to be to a large extent coming from the external seal not doing it´s job correctly. This could lie on the type of seal as you say and also individual cars-the bodywork and roof panel interface will vary from car to car I am certain. If there is too much variation in the gap bewteen bodywork and roof panel interface then I guess the job of the seal will be made even more difficult. I am sure that there is a degree of fine tuning that can be done on each car.
Look forward to hearing the results of your investigations.
I'll have a word with my dealer and see if I can speak to someone at the factory. They may respond better to a suggestion that a complaint....
Good news - today I had no wind noise at all
Bad news - I was in the Subaru
and that now has a puncture....again 
My thanks to the local Council for keeping the roads clear of bottles, nails and other detritus. grigio alloy said:
Hello `999´
as I mentioned earlier I will be taking delivery of my T350T Red Rose with Mk 2 roof design in May 2004. I read your comments with interest. According to the factory the road test of the T350T (against Z4 I believe), where the reviewer complained about wind noise was a MK2 roof. I think you are right that the noise has to be to a large extent coming from the external seal not doing it´s job correctly. This could lie on the type of seal as you say and also individual cars-the bodywork and roof panel interface will vary from car to car I am certain. If there is too much variation in the gap bewteen bodywork and roof panel interface then I guess the job of the seal will be made even more difficult. I am sure that there is a degree of fine tuning that can be done on each car.
Look forward to hearing the results of your investigations.
That's my gripe but I suppose I've only myself to blame as TVR did give me the option to take the T or wait for a new body shell. I was too busy drooling and jumping up and down like a kid at Xmas I suppose.
I'm kicking myself because perhaps the singular reason I didn't go for the T in the first place was that, given the less-than-scientific nature of TVR builds (and don't get me wrong, the fact that they are handbuilt is one of the reasons I love the car), I always knew there would be issues with the seals on the panels. You only have to look at other common niggles - door seals, boot seals, window seals - the pattern was there, I knew it, but was seduced by the idea of getting my car a few weeks early....
And, although there are some great suggestions in this thread, I want to drag it back to the original question;
Is it possible to convert a T back to a C?
I'm not about to go and do it, I just want to try and understand the feasibility of this, just in case (and it is just in case) all of mine and the factory's (and PHers) attempts at fixing it doesn't work. I have air con so I don't think I'd be that bothered about losing the panels. However I definitely do know I'd rather NOT have the wind noise, however that is achieved.
So far I've;
- Tried blobbing sealant on the finger brackets to make the panels fit tighter. No effect
- Running a bead of sealant behind and underneath the rubber seal on the panel in order to reinforce it. No effect.
Fish suggested making a hole somewhere in order that the pressure doesn't build up so much in the cabin (given that Ian's dropping-the-window trick does work). I think he could be on to something but how and where, without compromising the water-tightness of the car is the big question.
neil.b said:
Is it possible to convert a T back to a C?
Yes it is possible.
Make a mould using a C, larger than the aperture you need to close. Make a new roof section in the mould from GRP. Lay this over the T's roof and cut through both sections. Grind away the GRP on both the panel and the roof on both sides up to a few inches either side. Bond in the new section using GRP and overlay into the ground down sections. Sand down, fill, repaint, retrim inside.
Quite a lot of work and will make a hell of a mess of the inside of your car.
A simpler solution would be to bond your T panels in place.
griff2be said:
Is it possible to convert a T back to a C?
Yes it is possible.
Make a mould using a C, larger than the aperture you need to close. Make a new roof section in the mould from GRP. Lay this over the T's roof and cut through both sections. Grind away the GRP on both the panel and the roof on both sides up to a few inches either side. Bond in the new section using GRP and overlay into the ground down sections. Sand down, fill, repaint, retrim inside.
Quite a lot of work and will make a hell of a mess of the inside of your car.
A simpler solution would be to bond your T panels in place.
Cheers Andy. Messy but not impossible. Any guesses as to the man hours involved?
And I just checked your profile - my girlfriend is Wayne's neice! Small world eh?
neil.b said:
That's my gripe but I suppose I've only myself to blame as TVR did give me the option to take the T or wait for a new body shell. I was too busy drooling and jumping up and down like a kid at Xmas I suppose.
I'm kicking myself because perhaps the singular reason I didn't go for the T in the first place was that, given the less-than-scientific nature of TVR builds (and don't get me wrong, the fact that they are handbuilt is one of the reasons I love the car), I always knew there would be issues with the seals on the panels. You only have to look at other common niggles - door seals, boot seals, window seals - the pattern was there, I knew it, but was seduced by the idea of getting my car a few weeks early....
And, although there are some great suggestions in this thread, I want to drag it back to the original question;
Is it possible to convert a T back to a C?
I'm not about to go and do it, I just want to try and understand the feasibility of this, just in case (and it is just in case) all of mine and the factory's (and PHers) attempts at fixing it doesn't work. I have air con so I don't think I'd be that bothered about losing the panels. However I definitely do know I'd rather NOT have the wind noise, however that is achieved.
So far I've;
- Tried blobbing sealant on the finger brackets to make the panels fit tighter. No effect
- Running a bead of sealant behind and underneath the rubber seal on the panel in order to reinforce it. No effect.
Fish suggested making a hole somewhere in order that the pressure doesn't build up so much in the cabin (given that Ian's dropping-the-window trick does work). I think he could be on to something but how and where, without compromising the water-tightness of the car is the big question.
I think the roof is already `venting´ at the rear of the panel as it does not have the external seal on this part. Sensible as almost impossible for water to get in.
Getting the panel to mate up exactly with the roof must be a good start then maybe a different thicker external seal as 999 suggested.
I am confident the current situation could be thus improved but nonetheless I am still bricking it in case I get a `bad one´ even assuming the factory´s best efforts to get it right.
I feel for you Neil it is so frustrating-so near yet so far away because of this issue.
neil.b said:
Fish suggested making a hole somewhere in order that the pressure doesn't build up so much in the cabin (given that Ian's dropping-the-window trick does work). I think he could be on to something but how and where, without compromising the water-tightness of the car is the big question.
This can work, and the place to do this would be in the vertical back of the panels. However, as it seAms
to be the seals, the effect will be small. Boring, general theory: it's not reducing the pressure in the cabin, as it doesn't have any effect on wind noise when the car is closed, but building up the pressure on the back of the car. The result is the same, an overpressure on the back of the car, underpressure in the car, which will "suck" the air closer to the back of the body of the car, which will postpone the transition point of laminar flow into turbulent flow (making all the noise).
Practical:
If it's the seams, this solution won't be noticable, well, ... let's just say it won't be worth drilling holes in the body, as the seams will then be the cause of boundary layer transition ... NOISE.
If it's not the seams, it will definitely improve the airflow round the car and thus reduce noise. However, at 100mph+, you should certainly expect more windnoise than a T350C, due to the "bulbs" on the roof.
Another idea is to build some deflectors round the roofpanels, on top of the standard roof, in such a way that you have a nice flow of air round the roof, kinda like the roof of a Porsche Carrera GT.
It will increase downforce, reduce windnoise considerably, you won't have to make adjustments in the interior, and you will have a unique T350. If you don't follow the line of thinking, drop me a line.
Peter
Waveboy14 said:
Another idea is to build some deflectors round the roofpanels, on top of the standard roof, in such a way that you have a nice flow of air round the roof, kinda like the roof of a Porsche Carrera GT.
You could try this first in silicone, which is rather an inexpensive joke, while not destroying the body/paint of your car.
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