Noise levels - HELP!
Discussion
Can anyone suggest a good way of getting the noise level down to Castle Combe limits (100db)? My Spyder came with a second (quiet) exhaust that I'm going to try today, but the standard one that's on it at the moment came in at 113db at 4500 rpm so I get the feeling there's a hell of a long way to go to get to the required 100db! Not sure the 'quiet' exhaust will do it and am aiming for a track day at CC on the 3rd September!
Thanks in advance for any help...
Dom.
Thanks in advance for any help...
Dom.
I have re-packable rear boxes on my exhaust system. If they are empty (which they were when I got the car) it read 117dBa. With new packing, I'm down around the 98-100dBa mark (depending on how well I packed them, and the usual variabilities of measurement).
It only takes about half an hour to re-pack them, and it means that you can vary the noise as so wish
)
It only takes about half an hour to re-pack them, and it means that you can vary the noise as so wish
)I used them on my TVR Cerbera at Oulton. They're ok, but the trouble with all of these bolt on silencers is that they have a tendancy to drop off at the most inconvenient times. I had various types of exhaust inserts, and none of them came up with a really good means of fixing to the tail pipe.
They also increase back pressure, which can have a detrimental effect on power output. I found that the SuperTraps were the worst of the lot for power loss on the Cerbera, as they were so restrictive. My suggestion with the Ultima is to get a set of quiter back boxes for track use (or go for the re-packable option that I have).
James
>> Edited by james on Sunday 24th August 10:31
They also increase back pressure, which can have a detrimental effect on power output. I found that the SuperTraps were the worst of the lot for power loss on the Cerbera, as they were so restrictive. My suggestion with the Ultima is to get a set of quiter back boxes for track use (or go for the re-packable option that I have).
James
>> Edited by james on Sunday 24th August 10:31
I had a system made specifically for the track... it droped the noise at 5200rpm (the track req'd rpm for my AS 500bhp engine) by over 10db's.
It is now a real 98db's and I can not only pass the static tests but also the drive by's...... It was achieved by adding an extra three foot to the exhaust length with different back box's and going into a collector.
My system is still stainless steel so there is still more to be gained if you use mild steel.
See my site for a pic of it off the car.
It is now a real 98db's and I can not only pass the static tests but also the drive by's...... It was achieved by adding an extra three foot to the exhaust length with different back box's and going into a collector.
My system is still stainless steel so there is still more to be gained if you use mild steel.
See my site for a pic of it off the car.
Could always reprogram the rev counter and set it to 10 or 12 cylinders.... Or... get a good mate to noise test his car and then pinch the sticker...
Both versions tried and tested in the last year! Have Supertraps for the Ultima fixed by long bolt from one side to the other and sealed by making a gasket ring out of exhaust wrap. They work but mess the fuelling and sound awful.
Dave
Both versions tried and tested in the last year! Have Supertraps for the Ultima fixed by long bolt from one side to the other and sealed by making a gasket ring out of exhaust wrap. They work but mess the fuelling and sound awful.
Dave
I made a couple of add on sections to the end of each of the 3" diameter pipes on my Spyder. They give me 6dB of noise reduction (thats a lot) with hardly any power loss and simple clamp on to the end of the pipes, plus they look great or rediculus depending on your point of view.
Motorsports.com even had them on their web site for a while.
You just need a sheet of steel with ~10mm holes in it formed into a pipe about 300mm long, and cap the end off with an Aluminium tin (small Tuna fish tin is ideal but take the label off!). It works by distributing the noise over a wide circular area, the exhaust has to exit through a large number of 10mm holes over the 300mm length and not through the end, thus trapping a lot of noise, and also moves the nosie measuring device about 300mm from the end of the pipe - it all helps, sounds good and will set you back a good £5 or so. Tried and tested at several 100dB limit track days. I was 106dB even with a repacked silencer.
>> Edited by ultimanick on Tuesday 30th September 21:18
>> Edited by ultimanick on Tuesday 30th September 21:20
Motorsports.com even had them on their web site for a while.
You just need a sheet of steel with ~10mm holes in it formed into a pipe about 300mm long, and cap the end off with an Aluminium tin (small Tuna fish tin is ideal but take the label off!). It works by distributing the noise over a wide circular area, the exhaust has to exit through a large number of 10mm holes over the 300mm length and not through the end, thus trapping a lot of noise, and also moves the nosie measuring device about 300mm from the end of the pipe - it all helps, sounds good and will set you back a good £5 or so. Tried and tested at several 100dB limit track days. I was 106dB even with a repacked silencer.
>> Edited by ultimanick on Tuesday 30th September 21:18
>> Edited by ultimanick on Tuesday 30th September 21:20
doc_fudge said:Saw a guy in an orange GTR down at Goodwood last week with a pair of SuperTrapps on. After his first session the extra heat caused by the reduced exhaust size badly blistered his paintwork, melted wiring and popped out the rear lights! The inside of the engine bay was a real mess.
Has anyone tried SuperTrapp mufflers?
Does anyone know if they are any good?
I was at Goodwood last Monday and passed - 103/104db. ok, red line was 4.5k(!) so this was at 3.0k. Frankly, they are such good guys that if they want you on the track they'll ask you to rev to what passes! 2 f40's, porkers turbo's, AMGSL55 to name but a few of the exotica (and some Radicals and other single seaters). Lovely having a go against the F40's - what a car the Ult is - no replacement for displacement (I have to say that I have never driven another car which has overtaken an F40!) - late pm was wet - boy what fun!!
Have to agree it can bepend on the bloke on the gate...
My reading at Goodwood was 108db's but I didn't want to go on track just wanted the reading.
However I got stung the other way at Donnington where the guy had decided Ultima's were too noisy for the track (98db's was required) and stuffed the recorder up the pipe and anounced it was too loud defore I had even finished reving it......
He didn't even want to know what the car redlined at to know what revs he needed, shame I didn't turn up earlier as they didn't test the cars in the morning.
At bedford my car was tested at 5250rpm and passed with 99.5db's reading (at same rev the Ultima next to be went past 110db's!)
On the supertraps issue, I personnelly wouldn't fit these to my Ultima as I'm sure it might blow up.... or at the very least blow the exhaust off due to the flames out the back.
My reading at Goodwood was 108db's but I didn't want to go on track just wanted the reading.
However I got stung the other way at Donnington where the guy had decided Ultima's were too noisy for the track (98db's was required) and stuffed the recorder up the pipe and anounced it was too loud defore I had even finished reving it......
He didn't even want to know what the car redlined at to know what revs he needed, shame I didn't turn up earlier as they didn't test the cars in the morning.
At bedford my car was tested at 5250rpm and passed with 99.5db's reading (at same rev the Ultima next to be went past 110db's!)
On the supertraps issue, I personnelly wouldn't fit these to my Ultima as I'm sure it might blow up.... or at the very least blow the exhaust off due to the flames out the back.
I agree and it is a risk to pay and not play! Obviously my red line is 6.9k and not 4.2k! I am fairly sure that the Ult is quieter on drive by than on stand still as I was regularly redlining it past the sound monitors at goodwood and others said that mine was positively quiet in comparison to some of the "screamers".
ds
ds
Gassing Station | Ultima | Top of Page | What's New | My Stuff