Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: Mark_A on September 23, 2010, 10:21:15 PM

Title: Quieter exhaust??
Post by: Mark_A on September 23, 2010, 10:21:15 PM
Hi all,
 
I\'ve just bought a 92 Type R in Montego Blue, pretty pleased with it so far apart from one aspect - the volume of the exhaust!
 
I found this thread http://mazdarotaryclub.com/forums/showthread.php?t=31170 which is a bit old but suggests that the Racing Beat is one of the best choices for a fairly quiet system without strangling the engine - is that still the case or would anyone recommend a better alternative?
 
The car is going for mapping at WGT next week, and I see they do their own systems - anyone able to comment on how loud they are?
 
Alternatively has anyone running the HKS "Silent Hi-Power" system and does it live up to it\'s name?!
 
Thanks
Mark
Title: Quieter exhaust??
Post by: Nik da Greek on September 23, 2010, 10:25:23 PM
No! "Silent" in this instance is Japanese for "indescribably fduking loud". I had one on my first FD (admittedly with a decat) and it was deafening. It\'s got a 120mm outlet FFS!

Racing Beat is the quality quiet backbox to get tbh, I had one before the HKS and it was a great tone but loads quieter
Title: Quieter exhaust??
Post by: Mark_A on September 23, 2010, 10:55:29 PM
Quote from: Nik da Greek;717809No! "Silent" in this instance is Japanese for "indescribably fduking loud"
:rollin Thanks and nicely put!!
Title: Quieter exhaust??
Post by: dthebuk on September 23, 2010, 10:59:18 PM
best way to do it would be to go down the racing beat route. Though that will be very expensive. Or you could just have a look at the system for space to fit another silencer. Propper silencer\'s shouldn\'t restrict very much at all
Title: Quieter exhaust??
Post by: stylus350 on September 23, 2010, 11:33:09 PM
Said it then and I\'ll say it now - the RB was the muts nuts!
Title: Quieter exhaust??
Post by: efiniste on September 23, 2010, 11:36:29 PM
I\'ve got a WGT catback for sale at the moment. It\'s one of the quieter ones available, I\'d say it\'s on a par with the Racing Beat (which is what I replaced when I put the WGT on) and passed no problem on trackdays. I only did 600 miles with it before going V8 so it\'s barely used. £150 if you\'re interested
Title: Quieter exhaust??
Post by: Mark_A on September 24, 2010, 08:01:36 AM
Quote from: efiniste;717826I\'ve got a WGT catback for sale at the moment. It\'s one of the quieter ones available, I\'d say it\'s on a par with the Racing Beat (which is what I replaced when I put the WGT on) and passed no problem on trackdays. I only did 600 miles with it before going V8 so it\'s barely used. £150 if you\'re interested
Hi, yes I might be interested in this - what size bore is it, and does it have twin tailpipes please? Thanks
Title: Quieter exhaust??
Post by: efiniste on September 24, 2010, 09:05:37 AM
No, it\'s a single 4" slash cut tailpipe. 3" bore I think. I\'ll check and take some pics tonight.
Title: Quieter exhaust??
Post by: Mark_A on September 24, 2010, 09:42:27 AM
Could you email me a contact number please
 
"go dot mango at btinternet dot com"
 
Thanks
Mark
Title: Quieter exhaust??
Post by: efiniste on September 24, 2010, 10:08:11 AM
Done, Mark. Give me a ring whenever, I\'m available all day at the mo.

Steve
Title: Quieter exhaust??
Post by: SiH on September 24, 2010, 11:08:51 AM
Quote from: Nik da Greek;717809No! "Silent" in this instance is Japanese for "indescribably fduking loud". I had one on my first FD (admittedly with a decat) and it was deafening. It\'s got a 120mm outlet FFS!

Racing Beat is the quality quiet backbox to get tbh, I had one before the HKS and it was a great tone but loads quieter

The greek dude tells the truth :)
I had a Silent Hi Power on my Dirty Nissan - it was proper quiet. I test drove an FD with one on, and I thought it must be broken :Talking1
It\'s NOT silent at all!

I have a Racing Beat dual and I freaking love it - beautifully made, incredibly well fitting, and with a lovely tone. With a Tiger decat silencer, it tested 92dB at 4.5k at Combe, while still making 360 odd. Minty!
Title: Quieter exhaust??
Post by: probedb on September 24, 2010, 01:13:28 PM
Another alternative is SMB in Australia. I have one on mine and it\'s super quiet until I put my foot down :D
Title: Quieter exhaust??
Post by: Bulla on September 24, 2010, 02:38:35 PM
Mark do you have a silenced mid pipe ? If not thats the reason your exhaust is so loud, if you do then the Racing Beat or Amemiya Dolphin are nice a quiet at idle and not too noisy WOT.
Title: Quieter exhaust??
Post by: Mark_A on September 24, 2010, 02:59:51 PM
Quote from: Bulla;717941Mark do you have a silenced mid pipe ? If not thats the reason your exhaust is so loud, if you do then the Racing Beat or Amemiya Dolphin are nice a quiet at idle and not too noisy WOT.
I think the car is running 1 cat and the backbox (it was sooo wet when I viewed the car that I took the sellers word for this..)
 
I\'m pretty sure the current system is HKS (again sellers word, but everything else non-standard on the car appears to be HKS) and the tail pipe is huge - to the point of almost making the car look like a cartoon from the back!
 
I\'m going to take Steve up on his offer of a used WGT catback for now as he\'s quite local and it\'s a hell of a lot less than buying the Racing Beat.. I can hopefully get it fitted at the weekend and then if it\'s still too noisy I\'ll ask WGT to chuck another / better box on mid-pipe next week prior to mapping.
 
Thanks for all the replies
Mark
Title: Quieter exhaust??
Post by: Mark_A on September 28, 2010, 09:43:09 AM
Quick update, got the WGT catback from Steve on Friday and fitted Saturday. Confirmed the car is running both cats still but no centre silencer.

It\'s still loud!! It is a touch quieter and sounds a little deeper perhaps, and the smaller tailpipe looks better imho so I\'m pleased with it but as has been suggested above, it\'ll need an extra silencer before I\'ll be happy with the volume..

Taking it to WGT this eve so will add that to the to do list. I sense a big bill coming on!!!
Title: Quieter exhaust??
Post by: Nik da Greek on September 28, 2010, 09:47:45 AM
Both cats? :confused: Is it a UK car then, they had a pre-cat in the downpipe. Jap imports usually only had a single big cat under the car. You can only really fit a centre silencer by replacing the cat section with a sliencer section :3Confused

Big bills is part of FD ownership, sadly :(. Or life as a pelican :rollin......
Title: Quieter exhaust??
Post by: SiH on September 28, 2010, 09:57:48 AM
Yup - get a decat silencer. Or get a normal decat and a decent silencer welded into it. Will make all the difference. I\'m a a little tentative about what MY RB dual will sound like now I\'ve replaced the centre silencer with a straight through pipe.
Title: Quieter exhaust??
Post by: Mark_A on September 28, 2010, 11:34:42 AM
Quote from: Nik da Greek;718537Both cats? :confused: Is it a UK car then, they had a pre-cat in the downpipe. Jap imports usually only had a single big cat under the car. You can only really fit a centre silencer by replacing the cat section with a sliencer section :3Confused
Ah ok, you\'re probably right about the pre-cat then - I had a bit of a peer up that side of the engine whilst the cat-back was being fitted and it looked like there was something there more than just a downpipe, but it could easily have just been heat shielding around the pipe...
 
Hmm, not sure I want to decat though - I hate the exhaust smell you get without one and then it\'s the hassle come MOT time too...
 
Will have a chat to WGT and see if they can do anything creative?
Title: Quieter exhaust??
Post by: DrDan on September 28, 2010, 02:01:50 PM
Quote from: SiH;718542Yup - get a decat silencer. Or get a normal decat and a decent silencer welded into it. Will make all the difference. I\'m a a little tentative about what MY RB dual will sound like now I\'ve replaced the centre silencer with a straight through pipe.

Well, if it\'s anything like my "Racing Cat" (A euphamism for "cat shaped straight-through pipe" I suspect)... it\'ll sound excellent :)
My FD sounds a bit TVRish... but with added rotary excellence :)
 
Quote from: Nik da Greek;718537Big bills is part of FD ownership, sadly :(. Or life as a pelican :rollin......
The man speaks the truth... welcome to the Pelican Club :)
 
DrDan.
Title: Quieter exhaust??
Post by: SiH on September 29, 2010, 07:59:49 AM
Quote from: DrDan;718576Well, if it\'s anything like my "Racing Cat" (A euphamism for "cat shaped straight-through pipe" I suspect)... it\'ll sound excellent :)
My FD sounds a bit TVRish... but with added rotary excellence :)
 

Ubnfortunately it doesn\'t :( Turns out it sounds like a chicken chaser :( :( :(
Title: Quieter exhaust??
Post by: Mark_A on October 01, 2010, 08:36:16 AM
Well the car is back from WGT and I\'m very :):):)
 
Turned out the main cat was completely empty anyway, so they\'ve swapped that for a silencer and it\'s much, much better now.
 
Mapped to 280rwhp, which Pip seemed to think was quite decent given it\'s standard apart from PFC, filters and exhaust..
 
Oh and sorry to be dense, but the Pelican comments have gone Woosh! right over my head!! :3Confused
 
Cheers
Mark
Title: Quieter exhaust??
Post by: turbotoaster on October 01, 2010, 08:56:28 PM
hey mark, noticed your in longton, im in hanley, did you knock on my house a couple of weeks ago about my bonnet?
Title: Quieter exhaust??
Post by: Mark_A on October 01, 2010, 11:15:14 PM
Hi, no t\'wasn\'t me. Didn\'t have an rx7 to put a bonnet on a couple of weeks ago!! :D
Title: Quieter exhaust??
Post by: turbotoaster on October 02, 2010, 01:33:17 AM
ah fair enough, we should meet up though and chat rotary stuff, my car is always parked next to mango tree near northwood, you should pop over so we can compare notes :)

my email is turbo-toaster@hotmail.co.uk (turbo-toaster@hotmail.co.uk), send me a message and we will sort something out
Title: Quieter exhaust??
Post by: Mark_A on October 02, 2010, 03:09:16 PM
That would have been good, but.... you\'re Longton Staffs and I\'m Longton Preston, so not quite so local!! :(
 
I didn\'t realise there was more than one!! I\'ll have to revamp my sig now!
 
:cheers
Title: Quieter exhaust??
Post by: FD3S Efini on October 02, 2010, 03:51:18 PM
hey dude quick question you were mapped at 280 RWHP what was it at the Fly and what mods are fitted?
 
Cheers
 
Kris
Title: Quieter exhaust??
Post by: ro284 on October 02, 2010, 04:32:51 PM
Mark ,the quiet one is the Re Am Dolphin, i have one that has been re-packed and re-enforced, £100 but P&P would be costly,
Email ro284b@aol.com if you want to know anything, i sadly no longer have the car and it\'s in the way,
Bob
Title: Quieter exhaust??
Post by: davyv on October 02, 2010, 06:18:29 PM
Quote from: ro284;719222Mark ,the quiet one is the Re Am Dolphin, i have one that has been re-packed and re-enforced, £100 but P&P would be costly,
Email ro284b@aol.com if you want to know anything, i sadly no longer have the car and it\'s in the way,
Bob

What power is it good for 450+ .
Title: Quieter exhaust??
Post by: Mark_A on October 02, 2010, 08:00:48 PM
Quote from: FD3S Efini;719220hey dude quick question you were mapped at 280 RWHP what was it at the Fly and what mods are fitted?
 
Cheers
 
Kris
Kris, it made 280 at the wheels, 305 fly on WGT\'s rollers.

As far as I know the car is stock other than a WGT exhaust, twin mushroom filters, HKS hard pipes and a Power FC..
Title: Quieter exhaust??
Post by: FD3S Efini on October 02, 2010, 09:00:28 PM
Thats good figures for a pretty stock car it gives me high hopes for mine
 
Kris
Title: Quieter exhaust??
Post by: turbotoaster on October 03, 2010, 02:35:12 AM
i think one of your figures is wrong mate, if its 280whp it wont be 305bhp fly, an rx7 looses more transmission losses than that, 280whp is more like 330bhp fly
Title: Quieter exhaust??
Post by: Mark_A on October 03, 2010, 11:01:29 AM
Well I did think that 25 hp was quite a small amount to lose in transmission losses, that\'s why I quoted the wheel hp originally as that\'s what the dyno actually measures..

Less than 10% loss does seem low but WGT are very experienced in dynoing these cars so I would expect there to be some logic behind the conversion figures they use??

Anyway the car feels nice and quick and more importantly to me is delivering the power really progressively and from quite low down so it\'s really driveable - which it wasn\'t pre-mapping so I\'m more than happy for now :burnout
Title: Quieter exhaust??
Post by: turbotoaster on October 03, 2010, 12:39:44 PM
ive got a feeling i know what your looking at and it isnt the wheel hp, on pips graphs it produces one power with is yellow and another which is green, the green one is the power at the flywheel, the yellow isnt the power at the wheels, its on a seperate graph

there isnt any logic in the figures you have got mate

this is SiH graphs which was done at WGT

power at flywheel 362bhp
(http://i140.photobucket.com/albums/r30/Simon_r_hill/FDProject/PostMapping/IMG_1608.jpg)

seperate power graph for wheels 302.9whp
(http://i140.photobucket.com/albums/r30/Simon_r_hill/FDProject/PostMapping/IMG_1610.jpg)

so 59bhp losses which is about right, not having a go at you mate, just trying to help so you know what you have got, most likely you have 305bhp at the fly as your not far off a stock car, which is about 250whp
Title: Quieter exhaust??
Post by: Mark_A on October 03, 2010, 03:27:33 PM
No worries, I\'d rather understand the figures correctly and I think you\'re right - I\'ve got 2 graphs too and the green figures are 258.8 and 305.4 which makes more sense.
 
Question is then - what the hell are the yellow figures??!! :xconfused
Title: Quieter exhaust??
Post by: Mark_A on October 03, 2010, 04:18:29 PM
(http://www.bun.btinternet.co.uk/scan0002.jpg)
 
(http://www.bun.btinternet.co.uk/scan0003.jpg)
Title: Quieter exhaust??
Post by: SiH on October 04, 2010, 07:37:02 AM
It\'s the figures for a couple of different runs IIRC :)

Flywheel figures are sort of pointless anyways - they are all extrapolated unless the engine\'s been out of the car and on an engine dyno - I love how people quote an extrapolated figure to 1 decimal place, like they can be that accurate!

Can\'t remember as it was a goos while ago, but I think Pip\'s is a hub dyno, which means it\'s even more accurate than a wheel one :)

At the end of the day, if it\'s fast enough for you, then awesometown :) TBH there was only 20bhp ish between a couple of my mapping sessions, but what made the difference was all the bits in between - the throttle adjustability and general driveability - you\'re in safe hands with Pip :)