The91kwbeast
Active Member
- Joined
- Jun 12, 2022
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- Age
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- Location
- Sydney
- Members Ride
- VF Calais V
Hi all
As per @RevNev's suggestion at various points in this forum, I have finally found an extremely difficult to find set of large aftermarket rear mufflers, from an old RS Performance system (a rebranded VCM exhaust).
My objective was to fit these large mufflers to achieve:
a) A deep note
b) low or no drone levels
c) a quiet note at cruising and light throttle, and ideally keep total volume below 90db for a noise test
d) still a rorty loud-ish note when you're on the gas
Pics are below so you can see their size, they are actually larger than even the Holden mufflers. They are a 2.5" entry point straight through muffler with a single exit, perforated pipe inside with fibreglass packing, and fit the standard Holden/HSV exit point on the catback although they are the 2 bolt flange style.
The reason for me hunting for these unicorn mufflers, is because almost all aftermarket aftermarket rear mufflers use small oval straight through mufflers. Like this:
www.ultrex.com.au
These are universally terrible for drone at 1800rpm in automatics, and are too loud on most aftermarket systems. This is partially because they use single entry points but a dual outlet, but also simply because the body is only about 6" high so they simply are too small to kill drone and noise. They will usually enable a deep and rorty rumble though.
Note I currently have per my other thread a X Force VF82 system ( 1 3/4 long tube 4-1 headers, 100 cell cats into a 3" catback, which finishes in the standard position to enable Holden mufflers to fit).
The results are in and - they're pretty good!
I've score as follows:
a) 9/10 - nice and deep
b) 7/10 - Fairly good result. I've got a tad more drone than the VF2 bimodals when they are set to open but its pretty manageable. Versus closed there is a bit more, which for anyone who does a lot of highway driving may warrant some thought. As usual at 1,800-2000 rpm is where the drone zone is and when the car is cold, or you're on the highway with constant throttle going uphill it is there a little unfortunately but its much better than any small body diff back mufflers, simply because of the mufflers ability to absorb it. Rule of thumb with these cars seems to be louder muffler = more drone, unless you have bi modals or a J pipe to cancel it out.
c) 10/10 - Perfect. Nice note on idle not too loud, I did a quick rev with my phone to 3.5k rpm to try to test a sound test, and it didn't pass 90db. Its not a professional test but it gives you an idea. Modest volume level, and again nice and bassy but also it in no way sounds restrictive since its straight through
d) 9/10 - great result. As the revs build past 3krpm so does the volume, and it sounds rather good. I'm still getting in my tune the occasional pop which is more of a thunder crack, versus the VF2 bimodal.
I'd really like to put these to the test an have AFM turned back on in my tune to see how they go absorbing that noise also!
As per @RevNev's suggestion at various points in this forum, I have finally found an extremely difficult to find set of large aftermarket rear mufflers, from an old RS Performance system (a rebranded VCM exhaust).
My objective was to fit these large mufflers to achieve:
a) A deep note
b) low or no drone levels
c) a quiet note at cruising and light throttle, and ideally keep total volume below 90db for a noise test
d) still a rorty loud-ish note when you're on the gas
Pics are below so you can see their size, they are actually larger than even the Holden mufflers. They are a 2.5" entry point straight through muffler with a single exit, perforated pipe inside with fibreglass packing, and fit the standard Holden/HSV exit point on the catback although they are the 2 bolt flange style.
The reason for me hunting for these unicorn mufflers, is because almost all aftermarket aftermarket rear mufflers use small oval straight through mufflers. Like this:
HOLDEN COMMODORE VE VF MUFFLERS EXHAUST SS SSV SV6 HSV SEDAN
Ultrex Performance Commodore VE VF mufflers are a high quality polished stainless steel muffler to unleash the rumble of your VE VF V8 - or SV6
www.ultrex.com.au
These are universally terrible for drone at 1800rpm in automatics, and are too loud on most aftermarket systems. This is partially because they use single entry points but a dual outlet, but also simply because the body is only about 6" high so they simply are too small to kill drone and noise. They will usually enable a deep and rorty rumble though.
Note I currently have per my other thread a X Force VF82 system ( 1 3/4 long tube 4-1 headers, 100 cell cats into a 3" catback, which finishes in the standard position to enable Holden mufflers to fit).
The results are in and - they're pretty good!
I've score as follows:
a) 9/10 - nice and deep
b) 7/10 - Fairly good result. I've got a tad more drone than the VF2 bimodals when they are set to open but its pretty manageable. Versus closed there is a bit more, which for anyone who does a lot of highway driving may warrant some thought. As usual at 1,800-2000 rpm is where the drone zone is and when the car is cold, or you're on the highway with constant throttle going uphill it is there a little unfortunately but its much better than any small body diff back mufflers, simply because of the mufflers ability to absorb it. Rule of thumb with these cars seems to be louder muffler = more drone, unless you have bi modals or a J pipe to cancel it out.
c) 10/10 - Perfect. Nice note on idle not too loud, I did a quick rev with my phone to 3.5k rpm to try to test a sound test, and it didn't pass 90db. Its not a professional test but it gives you an idea. Modest volume level, and again nice and bassy but also it in no way sounds restrictive since its straight through
d) 9/10 - great result. As the revs build past 3krpm so does the volume, and it sounds rather good. I'm still getting in my tune the occasional pop which is more of a thunder crack, versus the VF2 bimodal.
I'd really like to put these to the test an have AFM turned back on in my tune to see how they go absorbing that noise also!
