quadra
Part of things
Posts: 162
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Hi Phil, I fully expect it to fail on the first attempt, but I'd like to get it as close as possible as it may fail on something big that requires a lot of work. You are right - having a real list of genuine fail items will make it far easier to hopefully get it passed. My local station is Hayes. A lot of the kitcar guys present a car that they know will fail, just to see what it fails on. Then they have a definitive list to work on. As Darkspeed has said, just make it functional the pretty stuff can come later. |
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Phil H
Posted a lot
Posts: 1,448
Club RR Member Number: 133
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If you haven't already had a look, there's a whole IVA section of the Locostbuilders forum.. Somewhat biased towards Locosts but the same test applies.
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Jan 10, 2017 22:42:13 GMT
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Darkspeed, Bias bar - they now require welding, but I don't want to do this as it would mean never being able to get the brakes undone for servicing again. Another dumb rule. They wont allow split pins through the locking nut but I think a roll pin through the nut should suffice - it's removable but only with specialist tools. Your thoughts? Yes this has been OK in he past, drill the nut and bias bar and fix with a roll pin. Sweet! thanks for that, another solution ticked off  |
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Jan 10, 2017 22:44:51 GMT
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Had a nice long chat with Darkspeed tonight - feeling a lot better now as he has put my mind at (almost) rest over several issues I was very worried about.
You guys are the best - thanks for all the support.
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Jan 10, 2017 23:05:47 GMT
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Nice to see a little optimism creeping back in!
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Jan 11, 2017 13:01:44 GMT
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Some goodies arrived today from a friend Ross (thanks mate) - Supertrapp ends - will have a play with these.  Also punched out some ally baffles at work today - Will see how these affect sound by fixing them to some 10mm studding & poking up the exhaust - theoretically they should offer considerable reductions.  |
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vulgalour
Club Retro Rides Member
Posts: 7,283
Club RR Member Number: 146
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Jan 11, 2017 17:32:39 GMT
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That's more like it  |
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Jan 11, 2017 19:21:01 GMT
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Keep plugging away - It is so close now!
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Jan 14, 2017 17:57:25 GMT
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Some good news today. I'n going to remake my nice stainless exhausts ends in mild steel in a new design - see photo below. The old design is on the left and the new on the right. The right angles in the exhaust will reduce noise as they will bounce the sound waves back againt each other compared to the smooth radius bends, this will reduce the noise output significantly according to advice by people who have done this. Pig ugly, but it will pass the test.  Next prong of attack is the baffling I got made at work, a quick bodge on some studding made this;  Which for a quick test got poked up the exhaust tip like this;  Now I only got 5 plates in the exhaust before it fouled on the weld line but a quick unscientific test in the garage showed idle Db's reduced from 96 to 92 and 3000 rpm Db's from 106/108 to 102!! YAY!!!!! So a combo of 90 degree bend exhaust and more baffling with maybe the Supertrapp ends as well should get levels down where they need to be Next was the MSD units - sharp edges again - velcro strips are for fixing the cover on;  So an aluminium cover was made up which will need to be covered in a thin foam layer (required) and a quick bit of trim to match rest of dash.  |
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jonomisfit
Club Retro Rides Member
Posts: 1,788
Club RR Member Number: 49
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Jan 14, 2017 18:03:19 GMT
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I'm another looking to see how to get through the IVA.
Car is fantastic and finish is amazing.
Keep up the great work.
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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Jan 15, 2017 15:50:31 GMT
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Nice to know that the sound reflective plates had such an immediate and positive result. As a simple demonstration of how effective absorption type silencing is to get a drinks bottle and speak into it. ![]()  Then put a sheet of kitchen towel in the bottom adding a sheet at a time up to 3- 5 sheets and speak into the bottle as each one is placed in the bottom. ![]()  If you build the log type section and it's not quiet enough, or you wish to put a bit more effort in with a few drill holes/mesh and a small folded sheet of steel you can modify it into a small rear box. Yellow is packed in rock wool, black shades are area's where you would drill or chop out and tack in punched mesh. Red outlines the sheet casing - pack in the rock wool as densely as possible.  The combination of reflection and absoption methods is very effective. |
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Last Edit: Jan 15, 2017 15:54:54 GMT by Darkspeed
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Jan 15, 2017 16:56:31 GMT
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if you extend the first tube as a dead end until it almost touches the exit one then pack it with glass wool it should absorb a lot of the energy coming from the downpipe in the same way as the drink bottle example.
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Jan 15, 2017 17:10:30 GMT
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Cheers Andrew - yes very positive results from the plates. Not quite getting the diagram - is the black part folded sheet like a zig-zag? Is the red line inside the casing or the new exterior?
Kevins, good call - what sort of glass wool? loft insulation? or special stuff? (got a spare roll of loft insulation)
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Darkspeed
Club Retro Rides Member
Posts: 4,878
Club RR Member Number: 39
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Jan 15, 2017 18:10:05 GMT
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Hi Mark,
The black is just to indicate the area which would be drilled or chopped out and replaced with mesh tacked in, like stuff you used to make the db tube - The red line is the outer edges of a piece of sheet steel to enclose all of the perforated parts and retain the rock wool - The two side red lines and the upper will be edges to weld to and the lower would be a folded radius that wraps around to enclose the other side where you would have a similar weld requirement. It allows a much greater volume of wadding and hence better absoption - Rock wool, wall/roof insulation material is what you want - the high density stuff.
You didn't have to use glass in the windows - You can use plastic - potentially cheaper but it also has to be correctly marked for automotive - plastic may save a few pounds - weight and cash and be available quicker.
Tyneside are probably one of the cheapest suppliers of specialist glass and can do heated front screen as well which may assist those who have removed heaters and lost the screen demist functions.
Sorry if teaching granny etc.
Your concern about emissions and the mods creating back pressure and messing up the mixture - Idle and 3000/4000 RPM without load is only using enough power to overcome the frictional losses of the internal components and the power required to drive the oil pump / water pump etc. - No power at all - This requires a tiny amount of fuel and therefore a tiny amount of air as the throttle is virtually closed at idle and just about open at 3/4000 rpm. The manifold will still be under a good high vacuum and be able to atomise the fuel very effectively (Providing the cam is not silly wild - but that's a very different subject to the exhaust) - So at idle and 2/3 test( or whatever it is) there is only a fraction of the exhaust gas volume that there will be under full power. The changes made should have no effect on the carb setting.
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Last Edit: Jan 15, 2017 18:32:47 GMT by Darkspeed
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Jan 15, 2017 20:28:04 GMT
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Thanks Andrew,
Just found a nice cheap supplier of mild steel tube, so will get that in a few days - will have a think about which way to build it after more testing with the baffles - I'll try putting them on the studding twice as close together so I can get approx 10 in the exhaust - see what effect that has.
Ref windows - Tyneside said they did not do it - apparrently it depends on who picks up the phone there? They are only marginally cheaper than Pilkingtons though.
Plastic would be cheaper but I did not want to swap the windows back after - to much messing around and it damages the window rubbers, also the plastic is not a lot less than the glass so I thought get it right and they last forever.
Good to learn about the emissions side of stuff - like I said, you have taken a big weight off my mind with your help.
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Jan 16, 2017 23:03:02 GMT
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Steering wheel now has a plastic cover with high density foam bonded on, so another job ticked off.   Ignition cover is also clad with high density foam,  and trimmed to match the car, not my best bit of trimming but it will do for the test.  |
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and trimmed to match the car, not my best bit of trimming but it will do for the test.
Thats the spirit!
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Jan 17, 2017 12:15:32 GMT
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One spoonfull at a time :-)
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Jan 22, 2017 21:06:24 GMT
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I finished one side of the new 'log' style exhausts today - it wont win any beauty competitions and the welds are not the prettiest (some big gaps to bridge on the fishmouths) but should be a bit quieter.  I say 'should' as it has not made a huge difference. Idle Db's are now reduced a little, but the 2500-3000rpm Dbs are still unchanged at around 108 which is a bit dissapointing. Poking my disc rod below into the exhaust brought the idle Db's to 92 and the 2500-3000rpm Db's to 102 so getting there.  The first big dead end will have rockwool with a mesh over it next to see what that does, then it will be a case of adding cuts into the exhaust and welding in half moon blanking plates untill it (hopefully) gets quiet enough. I still have the supertrapp ends to play with as well, last resort will be wire wool stuffed into it. |
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sonus
Europe
Posts: 1,392
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Have you measured which frequencies are the loudest? If you know this it would be easier to find a solution. A frequency sweep measurement of the car idling would tell you this. Doesn't need to be done using high end measuring device. An app for you smartphone should give you an idea. When you know the frequencies you can then make a helmholz resonator by lengthening one of the tubes as appendix. What it basically does is 'trap' certain frequencies in the appendix. EDIT: think of it as a trombone that alters frequency when you start playing. You could make an adjustable bit of pipe and alter the volum/distance by changing the length of the appendix. Oh and by the way do you measure the sound pressure outdoors or in the garage? Hope this helps some |
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Last Edit: Jan 23, 2017 10:00:50 GMT by sonus
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