Fixing GenPu Magnaflow Catback

[[R]usty]

Many of you who own a Magnaflow know that the design has one big flaw. The flex pipe flange that connects the catback to the racepipe has an opening that is only 2.4 inches wide. This is smaller than the stock exhaust and causes an exhaust flow restriction on a pretty nice aftermarket exhaust that purrs like no other. Some maybe turned off by this since it's not a true 3" exhaust but I have discovered a piece that will fix this issue while remaining under $600 shipped.

This issue has become quite annoying to me so I took action and looked for a part that would fit the stock racepipe and an aftermarket pipe like my Ultimate Racing. My searches led me to this item in the link below. It's a 3" flange that welds perfectly to this magnaflow. It costs $38 shipped and includes a male flange that you really don't need but could be useful to some. This is the lowest priced high quality flange I could find. Magnaflow sells their own but it costs $119 for the same thing. For those who want more info the Manufacturer: Flangex and part: FX8054
3" ExhaustConnector

This is a picture of the new flange directly on top of the old flange. The red outline shows where the old flange opening begins.


Now for some of you like myself who don't have tools to cut and weld a pipe, shop around and find a good quality shop the labor should be cheap and easy. My guy did it for $30 dollars and it only took 10 mins. Here's the finished peice.


Here's pictures looking through the pipe at the openings at the other end (old vs new). The new one as you can see is straight through without restriction.



I was not expecting much of a difference between the two but I was wrong. I took some logs and can clearly see my cars is running better without that restrictive piece. The old piece appears to have been causing my car to miss its boost targets. I'm not running a downpipe so any back pressure relief helps a lot. Before this was installed I was hitting 17 max psi trickling down to 16, now I'm hitting 19 psi trickling down to 17. My VD is showing an increase in HP and torque. FYI, this is my absolute best VD out of 15 logs for my old Mangaflow vs my second run out of 2 on my new one, all logs show the same trend (so I'm not crazy). ALL WERE DONE ON THE SAME MAP, SAME ROAD, ETC. Also, for those that are curious about sound it is a small bit louder which is welcome from a relatively quiet exhaust.

Overall, now, I'm pretty happy with my Magnaflow. It was purchased brand new for $500 shipped. The flange and weld cost $68 for a total of $568 for a great sounding, solid exhaust. For those who are not sure if this is worth the work I tell you the flange change added more power than the exhaust when I first installed it.

Others
$36 + $7 to ship
3" ExhaustConnector

$47 shipped. This one is the same company same flange just a longer pipe, will yeild the same results.
3" Exhaust Repair Spring Bolt Flex Pipe Connector Replacement Coupling FX3000EX | eBay

[Darthspeed3]

wow, I didn't think it would make much of a difference so I never really did much research. glad i found your thread.

[Hal]

Just purchased mine from hottexhaust.com...cannot wait for it to arrive....

[jpfrisch87]

I have the magnaflow as well. While it is a little annoying it's not a full 3" pipe, this is a good solution. Also, if anyone else is planning on buying one, the "vortex" coupon code is still good for 25% off from hottexhaust.com.

I have it with a test pipe, and that WOT sound still gets me every time..

[Kellerspeed3]

Will this work with a Cobb DP, I mean doesn't the Cobb taper down to 2.75 or something like that.

[Darthspeed3]

I was wondering the same thing but it's assume it works. I have a catted cp-e. That also works with the stock catback just like the Cobb. Really tempted to try this.

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[Kellerspeed3]

Originally Posted by Darthspeed3 I was wondering the same thing but it's assume it works. I have a catted cp-e. That also works with the stock cabal just like the Cobb. Really tempted to try this. Sent from my SAMSUNG-SGH-I337 using Tapatalk

Already ordered off the EBay site in the OP's first post, only 2 left.

[Darthspeed3]

Originally Posted by Kellerspeed3 Already ordered off the EBay site in the OP's first post, only 2 left.

Hey what did you pay just out of curiosity? I swear it wasn't $80.95 when I first looked. Now it is....


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[Kellerspeed3]

Originally Posted by Darthspeed3 Hey what did you pay just out of curiosity? I swear it wasn't $80.95 when I first looked. Now it is.... Sent from my SAMSUNG-SGH-I337 using Tapatalk

40 and change shipped.

[Darthspeed3]

Damn...its 80 and change now.

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[[R]usty]

Originally Posted by Darthspeed3 Damn...its 80 and change now. Sent from my SAMSUNG-SGH-I337 using Tapatalk

They are low on inventory so they're hiking the price. There are other vendors. I'll update OP with new links. They will probably lower back down to $38 when they get more inventory.

$36 + $7 to ship
3" Flexpipe Flange

$47 shipped. This one is the same company same flange just a longer pipe, will yeild the same results.
3" Exhaust Repair Spring Bolt Flex Pipe Connector Replacement Coupling FX3000EX | eBay

[Darthspeed3]

Originally Posted by rustysurfsa They are low on inventory so they're hiking the price. There are other vendors. I'll update OP with new links. They will probably lower back down to $38 when they get more inventory. $36 + $7 to ship 3" Flexpipe Flange $47 shipped. This one is the same company same flange just a longer pipe, will yeild the same results. 3" Exhaust Repair Spring Bolt Flex Pipe Connector Replacement Coupling FX3000EX | eBay

Thanks!!!!

[Kellerspeed3]

Came in today, pretty fast IMO, now got to find a shop I trust with my baby.

[ep87]

Man I'm glad I bought mine when they where $38. I cut the stock MF flange and got It tack welded in last night and I'll be burning in flange today, ripping out the stock system up two and including the second cat, and mounting the UR RP and the now much improved Magnaflow system. really great fix

[Kellerspeed3]

I'm running the Cobb DP, which is one piece, will I have to remove the DP to finish this job? Thanks.

[[R]usty]

@Kellerspeed3;

Are you talking about just reinstalling the midpipe, or did you weld the flange on your cobb downpipe as well? You shouldn't have to remove anything, if only reinstalling the midpipe, your cobb downpipe should flex enough to fit the piece back in. If you have to remove anything it would be the magnaflow piping.

[load]

The only thing I'd be worried about is that those flanges are aluminized steel. I had an exhaust done on my last car with that material and it rotted out within 2-3 years (Buffalo, salty ass streets in Winter). I also had to get one of the welds touched up after a year.

[Kellerspeed3]

Originally Posted by rustysurfsa @Kellerspeed3; Are you talking about just reinstalling the midpipe, or did you weld the flange on your cobb downpipe as well? You shouldn't have to remove anything, if only reinstalling the midpipe, your cobb downpipe should flex enough to fit the piece back in. If you have to remove anything it would be the magnaflow piping.

Nope, haven't done anything yet was just wondering out loud so to speak. I was under the impression that the Cobb DP tapered down to 2.75 or something like that where it connects to the exhaust, glad to hear that I don't have to remove that darn DP, thanks appreciate it.

Originally Posted by load The only thing I'd be worried about is that those flanges are aluminized steel. I had an exhaust done on my last car with that material and it rotted out within 2-3 years (Buffalo, salty ass streets in Winter). I also had to get one of the welds touched up after a year.

lol, well down here in Texas not so much, shoot when the roads freeze up a little they shut the whole state down, don't deal with snow very well down here! Lol.

[[R]usty]

Originally Posted by load The only thing I'd be worried about is that those flanges are aluminized steel. I had an exhaust done on my last car with that material and it rotted out within 2-3 years (Buffalo, salty ass streets in Winter). I also had to get one of the welds touched up after a year.

It's not a huge part of the exhaust maybe 2-3 inches long and the flange piping is actually larger than 3 inches and goes over the stainless section of the magnaflow. It's the flange that would have to hold up but I would be to worried about it corroding quickly. It hangs over the midbrace plate so I don't see it picking up a huge amount of debris but I could be wrong. A coat of ceramic paint would probably be a good idea for those in snowy climates. I'm in SoCal so I didn't really consider the metal type. The only weather we have here is the rare rainfall.

For those that are worried that this may corrode there is a more expensive flange made by magnaflow made of 100% stainless steel. I can't really comment on the fitment but I looks like a viable option.

Magnaflow 10745 Magnaflow Ball and Socket Flanges - Free Shipping on All Orders @ JEGS

[Miltron]

Thanks for the thread @rustysurfsa; I didn't like the restriction either, I went about it a little differently. I went to a muffler shop and they heated the restricted spot of the pipe, and then threw it in a hydraulic pipe expander looked completely open after he was done, no cutting required, the shop owner didn't even charge me - he was like it was fun and it wasn't a big deal - Price = $0

Granted most people won't have access to a awesome shop like the one I went to but maybe this will help someone.

[[R]usty]

Originally Posted by Miltron Thanks for the thread @rustysurfsa; I didn't like the restriction either, I went about it a little differently. I went to a muffler shop and they heated the restricted spot of the pipe, and then threw it in a hydraulic pipe expander looked completely open after he was done, no cutting required, the shop owner didn't even charge me - he was like it was fun and it wasn't a big deal - Price = $0 Granted most people won't have access to a awesome shop like the one I went to but maybe this will help someone.

Didn't know that was possible. Any pics of the finished product?

[Miltron]

Originally Posted by rustysurfsa Didn't know that was possible. Any pics of the finished product?

No sorry I don't - I had some pics on my old phone, it had problems so I lost the pics :-(

I do have a dyno pic though after it was done and tuned though.




Tapatyped

Pretty awesome we have about the same power results with the same mods basically


Tapatyped

[Hess22]

Thanks !

[[R]usty]

Original Supplier has restocked the part. Prices are back down to $39 shipped. If you've been holding off now is a good time to buy before they run out again.

3" Exhaust Repair Spring bolt Flex pipe Connector Replacement Coupling quick fix

[Jason43]

Did this on mine today. I used a 3" band clamp since I'm a cheap bastard this close to Christmas. The car definitely sounds meatier at WOT.

[[R]usty]

Originally Posted by Jason43 Did this on mine today. I used a 3" band clamp since I'm a cheap bastard this close to Christmas. The car definitely sounds meatier at WOT.

Any leaks? Did you have to cut slits in the flange pipe to compress with the band clamp?

[turbo test]

Already posted this pic in another thread but it better fits here.



Flange came free with my purchase of the used exhaust, I bought a generic 3in donut gasket from fastwrx.com for about $20 shipped and cost another $20 to cut and weld new piece on.



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[Jason43]

Originally Posted by rustysurfsa Any leaks? Did you have to cut slits in the flange pipe to compress with the band clamp?

I didn't cut slits but I probably should have. The new flange fit pretty snug and I didn't see any leaks. The only drawback I noticed from doing it this way is since the pipe on the new flange is so short, it doesn't give you much to work with. The exhaust ends up being about an inch too short once you've put it back together. I had to loosen the clamp in the middle of the catback and slide some pipe out(giggidy) to make up for it.

[ep87]

Originally Posted by Jason43 Did this on mine today. I used a 3" band clamp since I'm a cheap bastard this close to Christmas. The car definitely sounds meatier at WOT.

I was going to weld mine but I didn't have 309 SS mig wire, I could have used the standard mig wire, but figured I'd wait and see if I could find a flange in stainless vs. the ebay mild steel and take it to a friend and use his Tig.
So in the mean time I used band clamp like you, but a stepped/lap style which is a much better seal. and requires no slotting and eliminates any chance of leaking.
This is the next best thing to welding, super solid, cheap and easy. if you do use this method make sure and torque the clamp to the recommended 40-50 FT.LBS.
Walker/Dynomax part # 33272 $9.97 from summitracing.com

http://www.summitracing.com/parts/wlk-33272/overview/

[Elliott_HoltMZR]

Doing mine tonight! thanks for the great thread!

[Finchee]

The kit on ebay seems to be out of stock. I was looking for an alternative that was also stainless steel and found this one:

Kooks Headers Exhaust Connectors 7106SFEMALE - Free Shipping on Orders Over $99 at Summit Racing

Would the item listed above work?

An extra question is, is anyone who did the exhaust flange fix for their Magnaflow CBE, still running it on their cars? Or did you upgrade to a different, more audible CBE?

[turbo test]

Originally Posted by Finchee The kit on ebay seems to be out of stock. I was looking for an alternative that was also stainless steel and found this one: Kooks Headers Exhaust Connectors 7106SFEMALE - Free Shipping on Orders Over $99 at Summit Racing Would the item listed above work? An extra question is, is anyone who did the exhaust flange fix for their Magnaflow CBE, still running it on their cars? Or did you upgrade to a different, more audible CBE?

I still have mine, the drone (very little) is so much more tolerable than the stock exhaust.

I love the way mine sounds only downside is the slip fit connections but idc enough to swap it out with something louder

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[Finchee]

Originally Posted by turbo test I still have mine, the drone (very little) is so much more tolerable than the stock exhaust. I love the way mine sounds only downside is the slip fit connections but idc enough to swap it out with something louder

Thanks for the feedback. After I changed my tires to the new DWS06 tires, I am actually now able to hear more of the exhaust sound inside the car. I think that once I get the test pipe installed and get the exhaust flange fixed, it will be loud enough for me that I wouldn't want to get another CBE.

[Jason43]

I still run the Magnaflow. I like "deep and aggressive", but not "hey, there goes that asshole in the riced out Mazda" loud. The Magnaflow with a catless downpipe fits the bill perfectly.

[basspunk1001]

@Finchee; did you end up going with the Kooks header solution? I'm looking at picking up the Magnaflow and wondered how it worked out.

[Finchee]

Originally Posted by basspunk1001 @Finchee; did you end up going with the Kooks header solution? I'm looking at picking up the Magnaflow and wondered how it worked out.

I have not. I'm waiting on installing the CS 80mm Racepipe first, but that won't happen until later in the year. I have been told that the Magnaflow CBE will still mate to the 80mm Racepipe though its going to be really tight. Since the CS 80mm Racepipe is larger than 3 inches, CS support is actually recommending to have an exhaust shop come up with a solution for it, to make sure it fits their 80mm flange. This is the route I will probably take.

[basspunk1001]

Good to know, I've actually got the CS 80mm pipe mounted to the stock cat back right now. It doesn't fit well, but it doesn't leak either.

[IT GUY]

So everyone on here has a ball and socket downpipe.... I have a CNT downpipe with a flat 3" flange. I want to cut the exhaust flange and put a flat 3" flange but cannot find one with slotted holes and the holes are not wide enough on the ones I do find. If you look at picture you will see what i mean. Putting the Flat gasket on top of the flange i ordered, holes will not line up. HELLLPPPPP!!!!!!!!!! I currently just stuck a flat gasket on but it will not last long without leaking like that. I am in big time need of a flat 3" flange with the correct bolt distance. Does anyone know the factory bolt distance? that maybe help in finding the right flange.

[WetzMS3]

I ran into this issue when buying new gaskets.

Simple solution, ream or grind out the bolt holes into slots.

It's been a while since I found the right gaskets, so I can't recall numbers off the top of my head. I'll try to look through old invoices and see if I can find the supplier I found them at and a part number for reference and dimensions.

[IT GUY]

I will have to figure out how much room the slots in the down pipe have left or right. You may have a good point if I have room on the downpipe slots to move the bolts closer.

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