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ilya's 172 #BECAUSE_RACE_CAR



massiveCoRbyn

ClioSport Club Member
  Several
I can't seem to find the pictures I had under the car unfortunately, but this is the exit:

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IMG_20170507_163653 by Jon Scoltock, on Flickr

You can see in this picture that it drops down to come out under the side skirt on my car. I didn't want to cut the sill on mine, mainly because I was lazy. Something I might do in the future if I can be bothered.

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The 2019 Snetterton Stages 6a by Jon Scoltock, on Flickr

Can't find details of the old silencer I was using, but this is what I have now: https://www.jetex.co.uk/custom-exhaust-parts/U336300/

I also made four of these out of 1mm plate:

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IMG_20181113_171503 by Jon Scoltock, on Flickr

I started with just two, but was still borderline, so added two more. On my car, they are between the silencer and the exit. I just cut a slot into the pipe, slid it in and welded. Then put the next one 3" away, rotated 180 degrees, then another 3", rotated 180 degrees again. As I said, using two got me from 102dB to about 100. The second two got it down to 97dB.

The system itself uses the standard RS2000 4-2-1 manifold, no cat (because Q-plate) and a 2.25" system with the exception of the box, which is 2.5" (because no one did a 2.25" box in the size I needed. It's all heat-wrapped too - the manifold and whole system, excluding the silencer. The main reason for doing the system was to stop the tunnel getting hot, as I don't have any heat shields.

Worth keeping in mind that the MSA Yearbook stipulates that you should be a certain distance from any walls, as it could impact the result, so being near a wall might be influencing things.
 

RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
Oh thanks for that! Yeah car is like 40cm from a wall lol. So sound defo got amplified. Maybe I need to drop it and roll out in to the open. Hmm
Like the baffles! Watched YouTube vid last night guy made few different ones cones, spiral etc. So I knew I could use similar techniques if all fails. But only as last resort as don’t want any restrictions in the system! Because power #becaseracecar flames and shiiiit [emoji1787]

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massiveCoRbyn

ClioSport Club Member
  Several
No problem. Totally different car but hopefully still some use!

Just checked the Blue Book and it recommends that there is nothing within 3 metres of the vehicle to avoid false readings. That's when measuring at 0.5 metres which is the standard.
 

RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
No problem. Totally different car but hopefully still some use!

Just checked the Blue Book and it recommends that there is nothing within 3 metres of the vehicle to avoid false readings. That's when measuring at 0.5 metres which is the standard.

Oh I see. I was measuring a little closer haha. Yeah need to roll the b**ch out. Thanks!


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  Clio Williams
In my car from 101 to 96 db. At low rpm is really silent. We made it from two standard 90degres pipes
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RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
Straight cut dog gears ? Who are they made by ?

Can you not go sequential ? Wouldn't the cost be about the same ?

Yes Dogbox :) made in Holland. Sequential a lot more money. And less tourque. This will handle 600+ nm
Will be beautiful. +cant use sequential in any of the championships. Not that I think I will ever use this car for any. My sole and daughters college invested in this. If I even scratch the fucker I’ll cry for a week haha.


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RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
Quick update. Welded a second silencer in place. It’s 3.5” diameter with 2.5” inlet/outlet. 450mm long.
A quick test is showing its way under 105bd static most circuits use. But only at about 4000rpm as didn’t wait for it to warm up. Pointed the exhaust to the open side of the garage this time so it don’t get amplified. At idle it’s 89-90.
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RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
I've heard all tracks will be dropping their maximum noise limit and 105db wont be allowed any more? Looks like your ok for now though bud

I heard that as well. Let’s hope not. There are a few things I can do further to reduce Db. But think it’s fine for now


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RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
Good thing is, your doing the research and development and head scratching so we can all follow easily [emoji23]

Haha! Really do t mind lol.
This morning woke up thinking it’s still too loud. So decided to add 1 half moon baffle just before secondary silencer.
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Will see. If not enough can always add more. And based on my research this design, angled at 45 deg covering about 40% of the diameter has minimal restriction and negligible impact on power.


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RuskiWeldFab

ClioSport Club Member
  Clio 172, RS4 B7
All done ready to test!
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Sounds awesome. Nice and deep sound on idle. No drone! Inside the car only a tiny bit louder. BUT! According to my Db meter it’s still way too loud! This was out in the open. 5500 rpm. 59cm away at 45deg angle. Maybe my meter is phucked. Or it’s just too loud. Sod it! Ordered 24” 7x4” oval stainless silencer. Clearly 4” Jetex tubex silencer is shiite when it comes to absorbing the sound. Got some cool pic tho [emoji41]
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