Mazda Rotary Club

Cars by Model Type => 3rd generation RX-7's => Topic started by: gandyRX on March 07, 2009, 11:18:53 AM

Title: Exhaust question
Post by: gandyRX on March 07, 2009, 11:18:53 AM
right i have a jpracing exhaust from the down pipe with no cat, i need to take my car to work early in the morning but it is rather noisey and i dont really want to upset the neighbours, it came with a baffle cone type thing that you can put in the end of it or leave it out, it does quiten it down quite abit but i was wondering
 
if i do put the baffle in and drive it around will it damage the engine at all?
 
thanks
Title: Exhaust question
Post by: Macer on March 07, 2009, 02:31:41 PM
I\'m sure someone with a more expert opinion will answer this, but I\'m led to believe they are not a good idea as they\'re effectively choking the exhaust.

Proof of the amount of pressure that builds up is if you\'ve ever seen one come loose - they come out with a hell of a lot of force. I was traveling back with a friend of mine after he picked up his S15 - and that had a baffle fitted, but it wasn\'t screwed in properly. The thing shot out of the exhaust like a missile!! It was lucky it didn\'t go through the windscreen of the car behind :eek

I wouldn\'t want to use one, but that\'s just my opinion.
Title: Exhaust question
Post by: Timmy on March 07, 2009, 03:16:29 PM
I had a bung for my kakimoto which i got to appease the neighbours but it gets to hot to pull out very quickly. I don\'t think the bung is to bad for the engine but i couldn\'t be bothered anymore and got a new exhaust.
Andy i didn\'t think your was that loud or maybe i\'m just immune to the noise now.
Title: Exhaust question
Post by: gandyRX on March 07, 2009, 06:02:46 PM
lol last time you heard it, it was just a cat back, got a full 3.5 inch jp racing exhaust on there now, then it was remaped and pops and crackles like mad
Title: Exhaust question
Post by: clive on March 07, 2009, 06:08:11 PM
A restricted exhaust is o/k as if anything it will not let you reach the boost levels that your car would have been mapped at and their for be safe,

If it was the other way around and you fitted an exhaust that flowed  much more freely then you would risk over boosting and detonation if the air fuel mixture and boost levels were not calibrated / controlled properly,

In other words, strangling to a certain extent is O/K as all you would do is restrict boost and make the engine run richer, but making it breath easier potentially is not,

Hope this helps,
Title: Exhaust question
Post by: Timmy on March 07, 2009, 08:26:08 PM
Quote from: gandyRX;589479lol last time you heard it, it was just a cat back, got a full 3.5 inch jp racing exhaust on there now, then it was remaped and pops and crackles like mad

You drove past me the other day on a23 when i was walking up to the cafe, it is louder. I didn\'t think it was to bad as far as rx7\'s go, tho i could still hear you when you were out of sight.
Title: Exhaust question
Post by: gyles18 on March 07, 2009, 08:32:22 PM
i drove my rx7 from bognor regis to courchevel in the alps and back (about 860 miles 1 way) none stop (asides from petrol of course) and it was fine mate. i did take it out for the last part on the mountain roads just to hear it sing.
Title: Exhaust question
Post by: CharlieP on March 07, 2009, 09:35:38 PM
I think it depends on mapping- bleakboys was mapped for straight through...then it really struggled to start up when we put the bung in!!!