Urgent Flex pipe question

[projectmx]

My flex pipe snapped and so my exhaust is pretty much gone... i found someone who will do a stainless 2" from the flex point back for $200 and i was going to just buy a new flex pipe from mazda but it is $160 .... i need other options plus i read in here that the flex pipe is very restrictive... can a muffler shop take the two flanges from the flex pipe and make a new better one? can i get a replacement piece at a part store? any help or advice would be greatly appreciated

[ryanlindenberg]

jegs and jcwhitney carry them...i don't know if they have the right diameter for your application but the one i bought from them didn't look restrictive at all.

[93SOHC]

Most exhaust shops with a Walker or Gorelich exhaust catalog should be able to get you a universal flex section for about 1/4th of the Mavda price.

[JWMotorsports]

http://www.atpturbo.com

on the left side, click "our catalog"

got to "Flex Bellows"

2" Flex pipe is $18

2.25" is $21

2.5" is $32

They have a lot of handy universal parts, pipes, connectors, turbo's, etc...

[freyguy_412]

Flexpipe is restrictive, it's just the nature of the beast. They cause so much turbulence in the exhaust path it's unreal. I read about a guy using some kind of spring loaded studs on his header on his focus... didn't need a flex pipe after that.

Anyway, I'd say get a cheap universal one, have them weld some flanges on it and bolt it up... Dealership markup's suck a-- and your gonna get ripped hard for a "Genuine" Mazda exhaust product.

[JWMotorsports]

The style your referencing is like a ball joint style flange. I've seen them before. JEGS has something like it made by Flowmaster. You'ld have to have pretty stiff motormounts for this style though. Speaking of restrictive flex pipes....thats what caused the head on my car to lift before I tore it down for this build up (it's been over 1.5 years now). Good ole muffler shop used a 2.5" flex pipe....which was fine....EXCEPT inside it only had a 3/4" opening for exhaust to flow through! 14psi on a VJ-14 makes a LOT of heat even with the large APEXi front mount IC I'm using.

[Yoda]

There are several aftermarket replacement mfg that make a replacement flex pipe for you car. Bosal, Lapointe and Walker to name a a few. They usually retail for around $60-80. You are correct if that the flex joint is a source of major restriction due to 80% flexi joints are of the bellows. I started making my own a flexpipes a few years ago. I have a bunch of scrap mandrel bent pipe and steel plate in the corner of the shop. Recently I found a Canadian mfg near Toronto that make flex joints that have a smooth continuous diameter. With a 2" pipe and flex joint you should see about 4 to 5 hp at the wheels. The last pipe I made combined the outside radius of a 2.0" c/r bent pipe with the inside radius of a 2.5" c/r bent pipe grafted together to improve flow around the bent. To improve the volume of flow threw the pipe even more I added a merge reducing the diameter by about 1/3 the back to the original diameter within about 5-6" of the length of the pipe. This reduction in diameter improves low speed power and throttle response plus creates an effect that causes more volume of exhaust gases to flow through the pipe at a higher velocity than if it was a continuous diameter. On the dyno I saw another 3-4hp at the wheels over the previous tests. The total cost of material was probably $57. If matched to a chamber resonator and straight flow chamber muffler this will also have a positive effect on exhaust flow, SPL drop and can also extend this positive effect to the intake side of the engine drawing in more air that what could normally enter the engine.

[Tunes67]

Yoda.. will you make me an exaust system for my car please? LOL

Tunes67

[Devilhog]

Aye, same here


Wonder if a yoda exaust system would give your car force powers

[Yoda]

The only Star Wars movie I ever watched was the original when it was originally released in theaters way back when. I didn't pick the screen name it was given to me by the online MX-3 community long ago.

There is no magic power to getting these numbers. As rule of thumb reducing exhaust gas back pressure at the exit of the exhaust manifold = 1hp for every 3/4-1psi of reduction. More importantly velocity + a transition from a high to low pressure area creates a scavanging pressure wave. Throwing a bigger pipe on will reduce back pressure but at the same time reduce exhaust gas velocity which means the exhaust gases need to use energy for the intake air to push it out the exhaust pipe which reduced the amount of incoming air filling the cylinder before the intake valve closes. The goal is to create a strong enough negative exhaust pressure wave that it will draw more air into the engine than will naturally flow through the intake under normal atmospheric pressures.
In some classes of racing engine builders have been get up to 13 psi of positive intake manifold pressure this way for years.

[Ateana]

you pretty much need the flex pipe on the front of your exhaust its there to absorb shock and you can get flex pipe anywhere... grab yourself some flex pipe for like 10 bucks then a sawsall and a mig welder from a buddy and you can fix it yourself.

[forcedairram]

well actually you dont absolutely need a flex pipe, ive been running my exhaust now for like two or three weeks with no problems, well exept for the first day when i kind of sat the exhaust on a set of RR tracks, just welded it back up and havnt had a problem since, plus i have some pretty stiff motor mounts and plenty of slop in the exhaust anyway.