Initial build mods.
Discussion
With hopefully just less than four weeks to delivery, I have had a couple ideas which I thought it best run by the builder-gurus here.
Mostly to do with cabin noise improvement.
Firstly I'll be fitting a double skin and was thinking of including a cavity insulation system. Having looked at several types of vehicle and building construction insulation I'm favouring 25mm kingspan (used 100mm stuff on the house extension last year). It a sort of flameproof foam sheet bonded inbetween tinfoil.
I know Ted is not a fan and said that this was not the main area of possible noise reduction. However, I'm sure any background noise reduction must help to reduce fatigue on longer trips.
Secondly, Ted did say that one of the main sources of noise transmission into the cabin is from the solidly connected gear linkage.
Now as I'm not familiar with the G50 box yet, how fussy is the linkage/rod/selector connection to achieve satisfactory gearchange. (side mounted gearshift).
My idea was to insert a rubber bobbin somewhere along the length of the gear linkage rod. (a similar sort of thing that in the past was used to support the damper weight in a washing machine, or hold a Mini rear silencer up). When I was a youth we raced RC powerboats and decided to use these things as engine couplings on 25cc two strokes turning 2 1/2 inch waterscrews at 20'000 +rpm. They made a vast difference to the noise produced and coped well with the slight torque mis-alignment when under load.
Lastly, with all the very justified effort going into rivetting, (deburring, waxoil etc) has anyone used blind pop rivets in order to re-seal the chassis rail from the elements? (the factory demonstrator seemed to be built with stock 1/8th pop-rivets)
Mostly to do with cabin noise improvement.
Firstly I'll be fitting a double skin and was thinking of including a cavity insulation system. Having looked at several types of vehicle and building construction insulation I'm favouring 25mm kingspan (used 100mm stuff on the house extension last year). It a sort of flameproof foam sheet bonded inbetween tinfoil.
I know Ted is not a fan and said that this was not the main area of possible noise reduction. However, I'm sure any background noise reduction must help to reduce fatigue on longer trips.
Secondly, Ted did say that one of the main sources of noise transmission into the cabin is from the solidly connected gear linkage.
Now as I'm not familiar with the G50 box yet, how fussy is the linkage/rod/selector connection to achieve satisfactory gearchange. (side mounted gearshift).
My idea was to insert a rubber bobbin somewhere along the length of the gear linkage rod. (a similar sort of thing that in the past was used to support the damper weight in a washing machine, or hold a Mini rear silencer up). When I was a youth we raced RC powerboats and decided to use these things as engine couplings on 25cc two strokes turning 2 1/2 inch waterscrews at 20'000 +rpm. They made a vast difference to the noise produced and coped well with the slight torque mis-alignment when under load.
Lastly, with all the very justified effort going into rivetting, (deburring, waxoil etc) has anyone used blind pop rivets in order to re-seal the chassis rail from the elements? (the factory demonstrator seemed to be built with stock 1/8th pop-rivets)
One comment: There is a foam product that is distributed by profesional body shops that is called out for in the voids in both Lexus and Infiniti cars. It is a structual foam and actually does increase the rigidity of said cars when applied correctly. I filled all of the double walled areas in my GTR. Did it help? No way to know because I have nothing to compare it with. But.... when you wrap on the floor with a coin the sound that emits is very dull and dead sounding rather than live. If you get what I am trying to say with that discription. Now the last time I posted this suggestion some loon commneted that he would never do that to his car because if the car caught fire the foam would out gas and explode! Really, I'm sure that two no account makers like Lexus and Infiniti never thought of that. Any way for what irts worth I thought it was probably a good idea... But then so far I haven't caught the car on fire so I guess I don't no if the 16 gallons of gas or the foam would explose first. Lee
One comment: There is a foam product that is distributed by profesional body shops that is called out for in the voids in both Lexus and Infiniti cars. It is a structual foam and actually does increase the rigidity of said cars when applied correctly. I filled all of the double walled areas in my GTR. Did it help? No way to know because I have nothing to compare it with. But.... when you wrap on the floor with a coin the sound that emits is very dull and dead sounding rather than live. If you get what I am trying to say with that discription. Now the last time I posted this suggestion some loon commneted that he would never do that to his car because if the car caught fire the foam would out gas and explode! Really, I'm sure that two no account makers like Lexus and Infiniti never thought of that. Any way for what irts worth I thought it was probably a good idea... But then so far I haven't caught the car on fire so I guess I don't no if the 16 gallons of gas or the foam would explose first. Lee
738 driver said:
Firstly I'll be fitting a double skin and was thinking of including a cavity insulation system.
Yeah I used a sticky backed foam, which had a sound deadening mat against one side, and the heat proof foil the other side.. on the side panels i used the sound deadening mat i think rowdy is talking about.. I think I bought the foam from car builder soulutions, and the mat from acoustic solutions?..
I posted details before on here.. ill try and find them later!
738 driver said:
Lastly, with all the very justified effort going into rivetting, (deburring, waxoil etc) has anyone used blind pop rivets
Ive used waxoil and blind rivits everywhere ive drilled into the chassis..that'll teach me to answer before looking it up!!
http://www.pistonheads.com/xforums/topic.asp?h=0&a...
it was woolies and noisekiller in the end..
http://www.pistonheads.com/xforums/topic.asp?h=0&a...
it was woolies and noisekiller in the end..
would not recommened any rubber in the gear linkage ,you want a nice feel through the leaver and no play if you want good quick shifts !!!! a rubber would allow flex in the system which i think you would loose the feel .
To be honest the best way to reduce sound is going to be better exhaust boxes as this is were most of the noise comes from !!! Hydrolic lifters also help as there is lass mechanical noise from the engine ..
To be honest the best way to reduce sound is going to be better exhaust boxes as this is were most of the noise comes from !!! Hydrolic lifters also help as there is lass mechanical noise from the engine ..
LET ME EXPAND: I should have wrote this the first time. The product I used was SEM 39997 Rigid Urethane Foam "fills pillars, posts, box sections and around gas filler necks" "Set time is 1-2 minutes". This product requires a specail two tube applicator costs about $45. The foam in semi liquid form in two parts is mixed by the applicator and injected from the end of the tube into the cavity provided by the two paneled floor section. Small holes most be drilled to allow acsess. The foam will expand into the nooks an cranies of the space and a small amount will extrud out of your entrance holes. This can be trimed and sanded later. The panel will be very dead acousticaly when you are done. Several racers I have met have indicated that this process will cause these panels to also be more rigid after application. I will not argue that case, I have no scentific evidance to back it up, just the input of some knowledgeable racers. What I really like about this is that the dynamat is absoultley a great product but it is heavy. The foam is very light. Lee
Did you try soaking a sample of this foam beforehand.
The product does sound interesting, Ford used to use something similar the only thing was, after 12-24 months it could eventually become saturated and very heavy. That was many moons ago though and I'm sure expanding foam products have improved dramatically.
Lots of it is used in the UK window installation industry now!
I'll certainly have a look. Cheers.
The product does sound interesting, Ford used to use something similar the only thing was, after 12-24 months it could eventually become saturated and very heavy. That was many moons ago though and I'm sure expanding foam products have improved dramatically.
Lots of it is used in the UK window installation industry now!
I'll certainly have a look. Cheers.
This is what you want for combined sound dampening/fireproofing. It's self adhesive and I used it to good effect on the Can-Am and GTR:
http://www.woolies-trim.co.uk/pc-1619-129-foil-coa...
http://www.woolies-trim.co.uk/pc-1619-129-foil-coa...
Sir a little bit of this stuff seeped out were the cabels for the shifter went through the fire wall and was exsposed to the engine area. I recently had the motor out to dry sump it and took the time to clean up the little spot that was there.beleive me this stuff is like molten glass when it cooks off absorbtion will not be a problem. As to the comment about window sealents. I know exactly the product that you are talking about we built this house and got to watch that being applied. Great stuff for a house and reasonably cheap. The product I listed above is way differnt and certainly not cheap. Hope all this helps. Lee
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