Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: Sonic on July 16, 2015, 08:50:10 PM

Title: Which exhaust for track use?
Post by: Sonic on July 16, 2015, 08:50:10 PM
I'm picking up my rx7 next week and I'm keen to get straight on track with it.  The problem is its very loud,  it's a single turbo with a full bridge.  What exhaust system do I need to be buying? I need it to be at least under 100db. My local track cadwell has a 105 limit. Are the hks silent power any good?
Title: Re: Which exhaust for track use?
Post by: Rzla on July 17, 2015, 10:21:48 AM
Email address?
Title: Re: Which exhaust for track use?
Post by: C J R on July 17, 2015, 12:47:20 PM
Had same problem. I used Craig at TGS (Top Gear Stockport.) Brilliant quality and under 95dba.
Title: Re: Which exhaust for track use?
Post by: Alexsavv on July 17, 2015, 01:42:21 PM
I have the perfect exhaust for you

It's a 3.5" system, with a silencer in the middle and a hks ti-carbon back box (with a bung silencer)

Should bring you down to the recommended sound level!

Text me on 07972197435, Alex
Title: Re: Which exhaust for track use?
Post by: Mazdarotaryparts on July 17, 2015, 06:43:23 PM
Many many people over the years have used the Racing Beat 3" cat back that we supply with no noise problems,

Available as a Single tip and also as a twin tip, which  sells particularly to the stock cars  as the closest looking to stock you can buy.

http://www.racingbeateurope.com/bfd-ex001-racing-beat-single-tip-cat-back-exhaustb-1178-p.asp

http://www.racingbeateurope.com/bracing-beat-dual-tip--cat-back-exhaust-for-rx-7-fdb-1168-p.asp



Title: Re: Which exhaust for track use?
Post by: Sonic on July 17, 2015, 07:57:47 PM
Wow, thank you all for  the responses.  My email address is lukestorer4168@hotmail.com
Is good to see that I have options
Title: Re: Which exhaust for track use?
Post by: Casey on July 17, 2015, 11:23:00 PM
If you haven't got one, also worth picking up a cheap noise meter to do your own test. Make sure it measures dB(A) and not just dB(C) weighting (some do both). Nothing worse than travelling a long way to a trackday and finding they won't let you on track due to noise  :(

Something like this one, at £10.99 (might find one cheaper still if you look around);

http://www.amazon.co.uk/Digital-Decibel-Sound-Noise-Tester/dp/B009O5WXM0/ref=pd_cp_23_1?ie=UTF8&refRID=0BPFJS06VZB6R85511KV (http://www.amazon.co.uk/Digital-Decibel-Sound-Noise-Tester/dp/B009O5WXM0/ref=pd_cp_23_1?ie=UTF8&refRID=0BPFJS06VZB6R85511KV)

Be aware most tracks insist on you passing the "static" test at the start of the day (typically 105dB(A) at 2/3 of max revs, but could be as low as 89 at some events), but also have several "drive-by" microphones situated about 20m from cars around the circuit with a lower noise limit. Some cars will pass the static at 2/3 max revs but may trigger the drive-by if max revs produces a much louder output.

Good luck, and hope you might come along to one of the trackdays we organise throughout the year for MRC and RX8OC members.
Title: Re: Which exhaust for track use?
Post by: neil_jdmr on July 18, 2015, 03:06:43 AM
I use the RB single tail i bought from Clive above with a 3" straight centre pipe and 3" KSP downpipe and am usually around 94Db or less for static tests before the sighting lap.

when i used the car on the road i had a nurspec R back box and loved it unfortunately it was 122db so it was sold. The difference over just changing a backbox is remarkable.
Title: Re: Which exhaust for track use?
Post by: Sonic on July 18, 2015, 07:36:50 AM
I've already got a noise tester as I've had this problem before at Blyton with the drive by system they run. I usually do 8-10 track days a year so I'd love to join you guys on one. Just got to make sure the cars up to the task first. Looks like racing beat is the way to go. I do like the look of the hks silent power though but from the videos I've seen it doesn't sound that quiet
Title: Re: Which exhaust for track use?
Post by: neil_jdmr on July 18, 2015, 09:11:57 AM
I was in the same boat pal doing 8-10 trackdays a year and was concerned about the restriction for boost by using a more silenced exhaust. The RB single has been the perfect solution for me. All this year i have used the RB backbox with every other exhaust component as free flowing as possible and it doenst seem to have restricted exhaust flow even at high rpm.

Like i said ive never had an issue at croft since, as croft is renowned for being very strict on noise due to the high profile and very costly court case a few years back.

The other option is the TGS exhausts which ive only heard good things about but it wasnt feasible for me as he is 200miles away and would need the car for 3-4 days to fab it up.
Title: Re: Which exhaust for track use?
Post by: Casey on July 18, 2015, 12:33:27 PM
Quote from: Sonic on July 18, 2015, 07:36:50 AM
I've already got a noise tester as I've had this problem before at Blyton with the drive by system they run. I usually do 8-10 track days a year so I'd love to join you guys on one. Just got to make sure the cars up to the task first. Looks like racing beat is the way to go. I do like the look of the hks silent power though but from the videos I've seen it doesn't sound that quiet

Great stuff - we've got a trackday (am) + sprint (pm) event at Blyton in September (Sat, 19th);

http://mazdarotaryclub.com/forum/index.php?topic=83065.0 (http://mazdarotaryclub.com/forum/index.php?topic=83065.0)

We're hoping it will be mostly Mazdas (MX-5's, RX-7's and RX-8's) in the main, with a smattering of other cars to add some variety. The event is being mainly promoted through various Mazda online forums. Be great if you could join is. The discounted price EXPIRES TOMORROW  ;)
Title: Re: Which exhaust for track use?
Post by: Sonic on July 18, 2015, 01:24:53 PM
Yeah I'll be there,  a couple of my friends are booked on already.  One of them with a skyline powered escort cosworth. It's a really interesting bit of kit
Title: Re: Which exhaust for track use?
Post by: Casey on July 18, 2015, 01:26:49 PM
 :13: :13: I look forward to seeing you there (and I'll add you to the list!)

Have you paid up already?
Title: Re: Which exhaust for track use?
Post by: Sonic on July 18, 2015, 01:30:08 PM
Not yet,  I don't pick my 7 up till next week so I need to check it over first