jester
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 posted on 24/7/21 at 01:19 AM |
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Track Day Striker to loud
I have tried twice so far to pass the dB noise test at Castle Coombe
The first time I booked a slot it failed as it the was to noisey.
On getting the striker home I tuck the riveted Exhaust/Can apart it was like brand new
In there it was rammed with flat sheet packing.
The can had not long been brought for the car buy the last owner.
He said it was brought from RAW
The second time I Booked a slot a I fitted a dB killer in the pipe it still failed the dB test
The only mod's That the owner had done is to have the full bonnet hindge from the front
Picture 1 shows a cut out a hole in the bonnet
Picture 2 shows the cut out inside of the bonnet
Picture 3 shows a filter to a fiberglass box to the twin 40's
Picture 4 shows the fiberglass back plate on the twin 40's
The last picture shows the standard exhaust/Can
Would this make the striker to noise for a dB test.
The striker does have two stickers from old tracks day.
So all I can guess is that fiberglass box & hole in the boonet have made the striker to loud now 
 
Striker Bonnet Top
 
Striker Bonnet Underneath
 
Striker Carb Fiberglass box
 
Striker Carb Back Plate filter
 
Striker Stand alone F Filters
 
Striker stand alone B Filter
 
Striker Exhaust
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cliftyhanger
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| posted on 24/7/21 at 05:16 AM |
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The airbox and filter will be quieter than the twin sock type filters, and release more power. Plus teh induction is teh opposite side and a fair way
from the exhaust where tested.
99% you need a better exhaust.....
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pigeondave
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| posted on 24/7/21 at 08:05 AM |
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quote:
Originally posted by jester
In there it was rammed with flat sheet packing.
Hmm could be the problem. I was told 150-125g/litre for the packing, threads on here use the quilt stuff which expands due to the threads melting and
releasing it.
I cant remember the name, but I do remember most say use less than they say in the calculator. Do a search on here for repacking exhausts and
it'll show.
My exhaust repack is on JPSC forum "Stuffing the can".
Sound like a repack with possible slightly less material is your next option.
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JMW
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| posted on 24/7/21 at 08:42 AM |
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Acousta-fil?
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jester
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| posted on 24/7/21 at 10:38 AM |
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quote:
Originally posted by cliftyhanger
The airbox and filter will be quieter than the twin sock type filters, and release more power. Plus teh induction is teh opposite side and a fair way
from the exhaust where tested.
99% you need a better exhaust.....
That's a bit gutting as when I looked at the spare parts list on the Raw web site.
After I brought the striker for a price for a windscreen full or half size.
The can was listed at £250.00 Then to find out now that it's not fit for a track day
Glad I never brought the can myself.
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jester
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| posted on 24/7/21 at 10:40 AM |
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quote:
Originally posted by pigeondave
quote:
Originally posted by jester
In there it was rammed with flat sheet packing.
Hmm could be the problem. I was told 150-125g/litre for the packing, threads on here use the quilt stuff which expands due to the threads melting and
releasing it.
I cant remember the name, but I do remember most say use less than they say in the calculator. Do a search on here for repacking exhausts and
it'll show.
My exhaust repack is on JPSC forum "Stuffing the can".
Sound like a repack with possible slightly less material is your next option.
Thanks for the spec's & other links 
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jester
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| posted on 24/7/21 at 10:44 AM |
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quote:
Originally posted by JMW
Acousta-fil?
Found a good post on the web about this stuff
https://www.lotus7.club/forum/techtalk/acousta-fil-exhaust-packing?page=1
Looks to be the stuff
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adithorp
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| posted on 24/7/21 at 12:22 PM |
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Sounds like your exhaust might be over packed, as others have said.
I'd repack with acoustafil. Use the online calculator but then put in 25-30% less than it suggests. That's what's been found works
best in practice. It'll look pretty empty but once the quilting tread melts it'll expand to fill the space. You won't need the
stainless wire wool as pigeondave used if using acoustic.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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jester
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| posted on 25/7/21 at 12:19 PM |
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Here is some pictures of the currant packing that is in the Exhaust/Can
That was brought by the last owner from Raw
 
Description
 
Description
 
Description
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Sanzomat
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| posted on 25/7/21 at 01:30 PM |
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Just wondering what figure they gave you when you failed? If it was a long way over then it'll take a lot to bring it down (obviously) but if
not a lot over then tweaks might get you there. Remember it is a logarithmic scale so every ten dB is double the sound so if you were testing at, say,
108, then I doubt that repacking an existing can will get you below 100 but if you got, say, 103, when you failed you might get there.
If you are after a big reduction it'll have to be a longer and wider can.
Also worth trying (if you don't already have one) a 90 degree bend on the outlet pointing slightly downwards. I've heard just that alone
saving a whole dB and hardly any back pressure.
I've been to Combe a lot as it is only 11 miles from home. I've always found the guys to be friendly and helpful and they can often give a
bit of advice. For my BEC they accepted my saying I was trying a new map so was going to keep it below 10,500 so let me test at 7500rpm instead of 8k
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pigeondave
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| posted on 25/7/21 at 03:52 PM |
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quote:
Originally posted by jester
Here is some pictures of the currant packing that is in the Exhaust/Can
That was brought by the last owner from Raw
Ah well you got it open now, might as well carefully pull it out and weigh it and put in slightly less if its over.
Or go straight for the Acustafil (sp) option ?
Then again is it a case of the can is too small?
I'm limited of what I can fit in the side pod of the Fury. I've seen many a Stylus owner cut the side pod and have a bigger can exposed.
Horses for courses I think, if you want to do a lot of track days, massive can and you wont have the bother. Occasional track days, try repacking what
you have.
[Edited on 25/7/21 by pigeondave]
[Edited on 25/7/21 by pigeondave]
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jester
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| posted on 25/7/21 at 04:51 PM |
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quote:
Originally posted by Sanzomat
Just wondering what figure they gave you when you failed? If it was a long way over then it'll take a lot to bring it down (obviously) but if
not a lot over then tweaks might get you there. Remember it is a logarithmic scale so every ten dB is double the sound so if you were testing at, say,
108, then I doubt that repacking an existing can will get you below 100 but if you got, say, 103, when you failed you might get there.
If you are after a big reduction it'll have to be a longer and wider can.
Also worth trying (if you don't already have one) a 90 degree bend on the outlet pointing slightly downwards. I've heard just that alone
saving a whole dB and hardly any back pressure.
I've been to Combe a lot as it is only 11 miles from home. I've always found the guys to be friendly and helpful and they can often give a
bit of advice. For my BEC they accepted my saying I was trying a new map so was going to keep it below 10,500 so let me test at 7500rpm instead of 8k
dB reading was 108 the first time.The guy testing said this is a bike engine right I said no it's a 1700-Xflow
The second time I went it had a dB of 103 with a muffler in the exhaust end.
The exhaust has a 90 degree bend on the outlet all ready. As in the first lot of pictures.
I am booking the striker in for it's second mot shortly so I will ask them if they have a dB tester on site.
as the speedo has started running out now after 30ish miles@hr now so maybe the rev's are out as well now
So I may have been over reving the striker for the dB testing a Castle Combe
Its running motorbike digi dash for everything the fuel gauge has allways been a bit hit and miss
So fingers crossed on this. if not then repacking might help as other have said
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jester
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| posted on 25/7/21 at 05:19 PM |
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quote:
Originally posted by adithorp
Sounds like your exhaust might be over packed, as others have said.
I'd repack with acoustafil. Use the online calculator but then put in 25-30% less than it suggests. That's what's been found works
best in practice. It'll look pretty empty but once the quilting tread melts it'll expand to fill the space. You won't need the
stainless wire wool as pigeondave used if using acoustic.
You won't need the stainless wire wool as pigeondave used if using acoustic.
That's good to no.
That I dont have to buy the wirewool as well as it starts to get a bit of a dear job other wise
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bi22le
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| posted on 25/7/21 at 10:32 PM |
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What a pain.
If you are getting 108 static they is quite alot. I doubt it's intake side as you are not trudging on a drive by and as mentioned they box
should get the noise down.
I have a RAW exhaust and get about 98 static with acoustafil. Certainly worth repacking.
Also check for and holes in your exhaust.
Focal tip, unsure how you are getting your dB tests done but if you ask a day of so before you will be allowed to rock up at a track day and just get
it tested.
The marshals, if good ones, are often very experienced and helpful.
I hope you get it sorted and get to go out and play
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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Rich J
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| posted on 26/7/21 at 07:57 AM |
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Made the mistake of using the Acoustafil calculator so have a 2 foot by 4 foot piece left over if it's of use to you
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ttalps2000
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| posted on 26/7/21 at 10:00 AM |
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i have the same silencer. At IVA it was 99 and flickering to 100. After i repacked it with Acoustafil and was tested a few weeks ago at castle coombe
and is 96db, massive improvement. Just have to drive it hard and get it bloody hot to expand etc, i did about 150 miles non stop to get mine to where
it needed to be!
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perksy
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| posted on 26/7/21 at 09:09 PM |
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Repacked my SBD silencer with Acostafil and was very impressed with it
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jester
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| posted on 26/7/21 at 10:50 PM |
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quote:
Originally posted by bi22le
What a pain.
If you are getting 108 static they is quite alot. I doubt it's intake side as you are not trudging on a drive by and as mentioned they box
should get the noise down.
I have a RAW exhaust and get about 98 static with acoustafil. Certainly worth repacking.
Also check for and holes in your exhaust.
Focal tip, unsure how you are getting your dB tests done but if you ask a day of so before you will be allowed to rock up at a track day and just get
it tested.
The marshals, if good ones, are often very experienced and helpful.
I hope you get it sorted and get to go out and play
That it is.
They only have a few dates left at Castle Combe that can be booked this year as well
I missed out on two dates all ready trying to get this sorted
The testing has been done at Castle Combe on both times.
Have to book the time's as well
98dB sounds good
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jester
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| posted on 26/7/21 at 10:54 PM |
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quote:
Originally posted by Rich J
Made the mistake of using the Acoustafil calculator so have a 2 foot by 4 foot piece left over if it's of use to you
OMG 
Other post have said get the size then take off X-mount
Is it that far out
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jester
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| posted on 26/7/21 at 10:56 PM |
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quote:
Originally posted by ttalps2000
i have the same silencer. At IVA it was 99 and flickering to 100. After i repacked it with Acoustafil and was tested a few weeks ago at castle coombe
and is 96db, massive improvement. Just have to drive it hard and get it bloody hot to expand etc, i did about 150 miles non stop to get mine to where
it needed to be!
That sounds good.
150 Miles Tyres should last 
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jester
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| posted on 26/7/21 at 11:02 PM |
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quote:
Originally posted by perksy
Repacked my SBD silencer with Acostafil and was very impressed with it
Sounds like this is the stuff to get
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ttalps2000
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| posted on 27/7/21 at 07:31 AM |
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Dont tightly pack it though as it expands! It stinks for a while too, but the key is to get it hot. Wasnt until i went out on the motorway where it
got some decent heat into it that it began to quieten down
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