Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: matto on March 07, 2007, 06:25:33 PM

Title: is 70mm big enough for an exhaust
Post by: matto on March 07, 2007, 06:25:33 PM
at what point power wise would 70mm exhaust bore become a restriction?
thanks
matt
Title: is 70mm big enough for an exhaust
Post by: RobbieRX-7 on March 07, 2007, 06:37:38 PM
the standard system is 65mm so your only going 5mm bigger, not really worth it imo
Title: is 70mm big enough for an exhaust
Post by: probedb on March 07, 2007, 07:16:07 PM
3" (76mm) is good for well over 300 @ the wheels apparently.
Title: is 70mm big enough for an exhaust
Post by: TRex on March 07, 2007, 09:43:05 PM
A 70mm bore is v.good for a stock car and for a small/fair increase in mods.
As a matter of fact, I would say more than good enough for the twins at most stage of the cars mods.  
 
 But saying all this depends highly on the type of Exhaust system you want.  You can have a 70mm quality built, with very good flow characteristics exhaust that will out perform a bigger bore exhaust.

 Remember, Size does not matter! :Nono!
Title: is 70mm big enough for an exhaust
Post by: stylus350 on March 07, 2007, 10:57:12 PM
I have 3" EXTERNAL bore and make 500+ fly at 1.1 on a single, so think your ok, depends what mods you are considering/running.
Title: is 70mm big enough for an exhaust
Post by: matto on March 08, 2007, 09:27:39 AM
thanks for the replies the exhaust in question is the gram lights weight concept:
//www.mackinindustries.com/md/rays/57dragonexhaust.html
i plan to run a single turbo and break the 400bhp @ wheels barrier i liked the looks of it and it seems fairly quiet at 92db so would it be up to the job?
Title: is 70mm big enough for an exhaust
Post by: TRex on March 08, 2007, 12:02:50 PM
Hhmmmm, nice choice. :Thumbs-up

 I don\'t see why not, once the rest of your system is set up to match this.. then you should have the best of both worlds.  

 Stylus has giving a very good example....