Sensible yet free flow road exhaust

[PhilNic]

So I think I want the impossible. Currently running about 275 BHP with the boost up, colder plugs, FMIC etc. and of course free flow exhaust - HKS Hi-Power silent. I have a decat silencer or a cat for MOT time. Stock manifold and elbow.

BUT - I just don't love the car with the droning, and I want to fall back in love with it.

So can I get something with both freeflow characteristics, but also quieter? I was wondering if a custom build mild steel might be the way - I'd heard that stainless resonates more. I'd also like it to look pretty stock at the back (rather than the 5" bin) as I run the car as a sleeper. Mild steel isnt an issue as it doesnt come out in the winter, or even the rain very often.

If that's the answer then - any recommendations in the Essex/Herts area for someone to do it well (the last thing I want is to spend money and it not be quiet)

[sr20det1]

you are just down the road from me, we're in Bishops Stortford, unfortunately I have pretty much the same setup as you do right now so cant really help!
Quite like it tbh, we did have a couple of japspeed exhausts before that (think I still have the shotgun for sale) but the current setup is a good balance between looks and sound, not too loud but loud enough if you know what I mean!

[Mike41288]

Hayward and Scott are in Basildon and make really high quality exhausts. Might be worth contacting them to see what they suggest to remove the drone

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[BLAKTOOTH]

Lovely exhaust that and certainly the quietest performance exhaust available. I'm not entirely convinced a mild steel steel equivalent would be much quieter. Have you considered adding some sound deadening? You'd be amazed at the difference that would make inside the cabin. I used a little under my shifter to quieten a noisy box and it made a huge difference!

[Sidewaysfun]

Are you 100% sure you have the Silent Hi-Power and not just Hi-Power? I was running Silent Hi-Power, decat, PSM downpipe and Tomei copy manifold on my 180sc and registered under 80dB at Bedford static noise tests and had zero drone. My car was stripped too. You won't get much quieter than Silent Hi-Power. Perhaps you could add some more silencing or as mentioned look to adding some further soundproofing to reduce cabin noise/drone etc.

[Chriscooke]

A mongoose exhaust may be the answer. Possibly the quietest exhaust I’ve heard but it’s also probably not the most free flowing. Should be more than fine at your power level though

[PhilNic]

Hmm, thanks for all the input, good suggestions there. It certainly looks like a hi power silent, sizeable middle box, though struggling for decent pictures of them on the web. I think I might go down the route of consulting someone who makes customs like Hayward and Scott and see what they think. It's definitely way way louder than stock, not measured it accurately, but I would like something that is fruity when accelerating etc but doesn't drone. I have some deadening in the rear wings, I might try the boot floor to see if that helps.

[sx rider]

Get a decat silencer fitted, having been through the drone exhaust issue myself I think this gave a marked difference. I’ve also wrapped the whole system in heat wrap which helped too.

Running an apex twin exit which I think is the same as the mongoose.

There’s also the option the run a butterfly valve, close it on the motorway and open it when you want some noise https://www.ebay.co.uk/itm/333903256...QAAOSw55ZgOfvB

[pb63]

Hmm, thanks for all the input, good suggestions there. It certainly looks like a hi power silent, sizeable middle box, though struggling for decent pictures of them on the web. I think I might go down the route of consulting someone who makes customs like Hayward and Scott and see what they think. It's definitely way way louder than stock, not measured it accurately, but I would like something that is fruity when accelerating etc but doesn't drone. I have some deadening in the rear wings, I might try the boot floor to see if that helps.

I’m running hi power silent and it’s about perfect imo. If yours is a silent it will say so on the exit. It’s engraved on the exit and pretty obvious. The welds and quality of of the build on these is lovely…

[PhilNic]

I’m running hi power silent and it’s about perfect imo. If yours is a silent it will say so on the exit. It’s engraved on the exit and pretty obvious. The welds and quality of of the build on these is lovely…

Right, thanks for this, I think that solves the mystery, mine doesn't say silent! Bum. Does anyone know if both boxes are different? IE could I just change one half.

[leonl]

As above HKS silent has silent engraved into the tip.

Adding a sports cat will help reduce noise instead of the decat pipe.

Your probably find both boxes are different