musdavis

Ok, so I've decided I want to up the performance of my96 uk by adding a new exhaust, however in order to keep the mrs happy I ideally don't want it to be any louder, though I appreciate that higher performance also comes at a price (in decibels!).

What's therefore the best exhaust that won't make your ears bleed?

harvey

iTrader: (48)

Revolution.

theotherphil

Ditto. I have the Revolution 3" decat system and downpipe and it sounds great without being overly loud inside the cabin. It's very easy on the ears on a long motorway journey also!

musdavis

Thanks guys, looks like the Revolution is a clear winner for this poll.

Jay m A

iTrader: (2)

However.

It would be fair to say the Revolution is the quietest single box 3" full decat system, capable of flowing 400+ BHP, therefore "the best"

But if your aspirations are never going to that level, say 300 BHP max then I think there are quieter full decat systems, 2.5" with 2 silencers, that do not flow quite as well as the Revolution - but has more than enough flow to do the job.

I'd give H&S a ring, they do 'quiet' versions that do not comprimise flow too much.

BTW, i have a H&S 3" downpipe, with the Revolution centre and backbox.

Another point is to get stainless steel headers. More power AND quieter!!

Mick

iTrader: (1)

Jay - which stainless headers? presumably not just a copy of the original as that wouldn't affect power or noise. Do you mean the equal length headers which give more power but lose the 'Scooby beat' from the exhaust?


Mick

Jay m A

iTrader: (2)

I can only go from personal experience with the Megans. They are unequal length, but less unequal than OE IYSWIM. This helps, but I believe the difference in materials also has an effect (steel vs iron). You can still have the burble and reduce the noise, although the Megans give a sound more like a bike engine on full chat!

Houghton

iTrader: (1)

Who sells the revolution system and what sort of price are they? I've tried search engines without success.

I had a noise test at Bedfs Autodrome today and got an 85 on drive by, limits 87db. Is the Rev. much quieter?

Thanks

theotherphil

http://www.revolution.eu.com/

Houghton

iTrader: (1)

Thankyou. I'll give them a call for noise levels.

Still don't come up on a search though

StickyMicky

revolution system seams to be on most of the TTS cars

its not to loud at all when your in the car, although it does get a bit more noisey with a decat downpipe

its easy enough to drive down motorways and such, without it destroying your ear drums after a while

peachy wrx

i have a power engineering full system and thats not very loud.......which suits me just fine!

911

My Sti v3 has a Magnex 3'' full decat, back box only system with wrapped Gruppe S headers and measures 87 dB on the race track.

Only comments i get about noise is

'Sounds like there is pleanty of room for more development!'

This system will drone though at 75mph....rummm...rummm..rummm......rummm

Super.

Graham

Houghton

iTrader: (1)

I personally don't have a problem with the noise, 3" H&S down pipe, Gruppe-S headers, Scoobymania 3" resonated centre and what I think is a 3" Magnex box. I happily drive the 400 miles to Dundee about 3 times a year and have done 750 miles in a day without a problem (how many cars can you say that about?).

Just don't want to get kicked off track for being too noisy.

Spoke to someone at Revolution and was told it's 96db drive by

I phoned H&S last week and was told they quieten theirs by reducing the bore.

Maplin do a noise meter for 30 odd quid so I think I'll get one. It may not be too accurate (not calibrated) but at least it will be OK for comparisons.

Gerry

911

Gerry:
Noise testing at a hill climb:

Car static and hot.
Noise meter microphone 1 meter from exhaust tip
Engine held at 2/3 max rpm (66% of red line) for 3 seconds
Peak reading indicated is what you are judged against.

Graham.

Houghton

iTrader: (1)

Hi Graham,
Track day testing, depending on circuit (some don't bother),
Noise meter 0.5M at 45o from exhaust tip, at 3/4 of red line

But they also have drive by meters at various points around the track.

My gut feeling, after Saturday's test, is it'll be OK for most. Goodwood & Bedford are the most stringent I'm likely to encounter. G/Ws a 98db static test.

Suck it and see I suppose but at £200 for the day, I'd hate to be just a spectator

Peanuts

iTrader: (15)

hayward and scott downpipe, revolution centre and silencer, GT spec headers.

very quiet, lovely

john banks

Goes without saying that the more airflow you make the more noise it will make. Mine sounds quite civilised until you turn the boost up... I have Revolution 3" with plumbed back in external wastegate, with three (yes 3) extra resonators in the exhaust.

Houghton

iTrader: (1)

I've noticed you tend not to do things by halves John

john banks

I do cut a lot of corners I am afraid in the interests of keep the costs down (standard Subaru parts bin stuff wherever possible) and it sensible on the road. This exhaust was AlanG's.

ScoobySport (SdB)

Gents

We are a about 2 weeks away from launching our new exhaust system.

It contains an advanced performance cat in the downpipe, a resonator in the centre section, and revised scoobysport rear silencer.

I am currently running this on my car, and whilst I am bound to be biased I can honestly say it is the nicest sounding scooby exhaust I've ever heard. It is a bit louder than standard, but the exhaust note just sounds stunning.

It will not be for those who want decibels... but for those who want a legal exhaust which sounds beautiful without being intrusive to the cabin, or the neighbours, it will be ideal.

I am dreading saying this next part due to the possible responses, but we have also reached a stage with the classic shape car (and are currently very close on the new-age car) with the development that the full catted system performs all but a tiny measurement as well as the de-catted system.

This was something I didn't appreciate was possible, but was convinced of it by our engineers after being told about the work they did on the rally cars to produce the same result.

Its a risk for us as we've spent a lot of money developing it, but I am hoping that there is a demand for it, and to be honest, also just felt it would be a good fun project - which it has been.

All the best

Simon

StickyMicky

will it pass the ruthless scottish police test?

ScoobySport (SdB)

lol

currently it looks like it will. We'll publish figures once its finalised.

911

this is very interesting.
Will you be brave enough to give the 'loss' of bhp/torque through the rev range between decat v cat versions?

I want a quiet system and one that will run as well as a decat.

Currently have 407 bhp x 340 2 litre, can you flow well enough to keep it (very old style Magnex 3'' decat at present.
I hill clinb my Sti v3 and need all the performance AND the low noise level. Current dB is 87 with this system.

I hope you can put the icing on the cake and offer a 3'' at a good cost.

Good luck!

Graham

Floyd

iTrader: (9)

Will this be launched before or after the suspension system?

F

ScoobySport (SdB)

Hi Graham

Honest answer is that I couldn't be sure that the standard system would work as well as a de-cat on your spec car until we conduct proper tests - but I would hand on heart say that it is very likely to actually improve performance rather than reduce it.

Is the turbo standard? or at least the exit mouth?

We have found that our new 2.5" design actually flows and performs better than any 3" systems we've tested with, and certainly improves turbo response.

Regarding whether we would publish the full rev range. Absolutely. The peak horse power figure is a nice easy way to market a product, but as most people on here realise, the true performance benefit comes from the torque curve, rather than the peak, and turbo response on the open road, rather than a flat throttle on a rolling road.

If your turbo is standard, or at least has standard fittings, I'd be happy to look into testing it with you. Let me know, as it would be interesting to see.

If the turbo is non-standard, it may mean a very big development job to get it all working correctly, but you never know.

Cheers

Simon

911

Simon:
Good (but rare) to see a supplier with such an open attitude!
This is how to sell product!

The turbo is a 'straight' AndyF TD05 20g with all the classic mods on a stock Sti v3 engine.
I actually do not like driving the car with a decat for fear of the law but also a twinge of 'Green' in my heart!
My car will cut about 9 mpg at full chat in the push for racing performance, but if I keep my place in the class this weekend I will probably fit the Jap sports cat back on and see if that affects the performance of the car on track.
Blasting around on the road is not really of much interest tbh but a good cruising system that flow very well when all is let loose on a hill climb is interesting.

I find it intreging that the 2.5 flows as well as the 3'' (presume the 2.5 has the cat), as the car will deliver 407 bhp(340 lbft) on the RR (probably more realistically 380/390) on the old Magnex system, so to get a benefit, your new system would need to be prety good.

Also, do you loose much ground clearance on your system if you have staightened the pipe as much as possible.

Again, great to see a supplier talk in the open; join the ranks of Powerstation, API, LEDA and AndyF, most welcome.

Graham

FASTER MIKE!!

tsl group n system is fairly quiet too but only a 2.5inch

mike

ScoobySport (SdB)

Hi Graham

Thanks for the kind words mate

Regarding the 2.5 performing better than a 3". I don't even pretend to fully understand all of this, but aparently the deal is ...

A bigger diameter has more gas in it, and therefore requires more effort to accelerate that gas out of the tube (through all the bends, silencers, etc).

This means a smaller diameter is generally better at low revs.

The problem with smaller diameter exhausts is that once you get to high boost / high revs, there is such a massive pressure advantage from the turbo exit compared to the back pressure in the exhaust that all you really want is as much room as possible to get rid of the gasses.

The "special" (for want of a better word) thing about the scoobysport 2.5" system is that it takes advantage of "scavenging" which is effectively a culmination of reflected sound waves through the entire system, and remarkably (aparently this is incredibly rare) creates true negative pressure at the turbo exit. This means that once the revs get into their "sweet range", the gasses are actually "sucked" out of the turbo rather than just being allowed to escape.

This is believed to be the most fundamental difference which give the scoobysport system its turbo response advantage over other exhausts.

In top level motorsport, this scavenging effect is the holy grail of exhaust design. Its not always actually possible to achieve, and even if it is takes significant development and extensive testing to stumble across it. You can computer model your way part of the way there, but the rest comes from good old fashioned trial and error.

Since running scoobysport, I have discovered that there is a big difference between making an exhaust which works, and making a serious performance exhaust system. Its been a bit of an eye opener to be honest

Cheers

Simon

Agressive

I got a HKS HI Power Silent Exhaust and its excellent! Absolutely love it