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M2 Exhaust install and review (bonus stock header work)

7K views 11 replies 8 participants last post by  B8_RDC 
#1 · (Edited)
Over the holiday I nabbed some time early AM to install the M2 exhaust. Grabbed it off fleabay since shipped to my house was about same price as Dream1 and came with new piping/tips/etc. Scroll down to bottom for review, install story below:

Tools (IIRC): 10mm/torq bits (various plastic guards), 13mm/15mm (stock exhaust & headers), 17mm (m2 bolts), 19mm (wheels), breaker bar, socket extensions, universal joint, Dremel, hammer, PB blaster and various protection.

The removal of the stock exhaust was brutal. All the bolts off the headers were severely rusted, one nut actually was pure rust (poof). No amount of PB blaster could spare them and had to use Dremel to slice them off. Thus I decided to remove the headers in order to get enough room for Dremel bit. Glad I grabbed an O2 socket when at the parts store.
Before (ah crud):

The remains (hours later...)

Reminder to wear eye, ear and respirator/air filter while doing such work. I then opened up the stock header flange holes so I could get new bolts through and have a bit of "play" for alignment.

Since I had to take headers off, I decided to hit them with wire brush and do some minimal porting. Used the Dremel again to remove large pieces of weld and slag from the exhaust area and then hit them with brake cleaner to get off oil and PB blaster remains. After that I had some 1500* header/heat wrap silicon spray left over from earlier GP install and hit them with two coats.

Glad I read the gaskets were re-usable since that made me decide it was ok to remove the stock headers in the first place. But to be safe I hit the gaskets with copper spray to ensure a good seal.

Reinstalled the headers with ease and tightened down the O2 sensors.

So now after the unplanned mods to the stock headers, I finally could go about installing the M2 exhaust. Surprisingly the fitment of the piping was great, no gaps and the included gaskets and bolt hardware fit well. (after opening up stock header holes)

However, the M2 creators apparently did not make a jig for the mounting section. The alignment on those were very sloppy. See two pics below.

Also another negative IMO was how the planned distance of tips exiting rear of valence. Given the great pipe fitment it appears they thought this would highlight the new chrome but really should be 2" shorter on each side. Going to leave it as is until Dec and see if I feel like chop/TIG them shorter.

Pics of installed results and also temp zip ties (race yellow) until can hit the brackets w/ plasma cutter. The metal on the M2 brackets is amazingly strong and will not allow Dremel or drilling.



Review: Upon start-up I did not get any "snow" or fiberglass out of tips like another post mentioned. The idle is great and sounds just like the stock. Early RPMs have deeper and louder than stock and upper RPMs is screaming. The design appears to mimic borla in having straight perforated piping with sound deadening pack around it, so makes sense in higher exhaust velocity more sound will escape.

Driving on the freeway in 6th around 65+mph or so the exhaust is dead quiet (near 3k RPM). Under load, just like stock on freeway, there is more sound but not the drone I've experienced in past cars that had a flowmaster or such installed. The car was much faster but then again I also swapped air filter, spark plugs and did various fluids at same time.

Bottom line: Hard to beat for price, weight and sound. Others don't even notice the tips sticking out.

Pros:
-Great welds and piping fit
-Strong material used + included hardware
-Price
-Weight + sound

Cons:
-Bracket fitment fail
-Removal of stock headers to enlarge bolt holes
-Tip distance design
 
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#4 ·
#5 · (Edited)
Thank you for documenting your installation. Those flange bolts are a nightmare to remove once the car has a few thousand miles on it.

Seems like you are pretty handy with torches and cutters. It may be worth your while to take a look at this thread and our experience with an aftermarket exhaust and stock headers.

http://www.planet-9.com/cayman-boxs...ed-headers-byproduct-aftermarket-exhaust.html
Thanks for the link. I will let you know how my stock headers fair but appears bad weld would be my guess on that thread. If it is weight related then I think I can sneak by, M2 is so light I have it suspended by zip ties at the moment. I actually coated the stock exhaust to try and keep that area as hot as possible for more gas velocity.
 
#12 · (Edited)
Yes eBay and very inexpensive. If you have the tools to adjust the tip length they are a hell of a deal. I've been out of the country for work so haven't had time to grab sound clip yet. Really great sound but may be loud for some tastes.

If you don't mind the tip placement then using wire should be sufficient on the misaligned brackets. Piping fit great for me so no issues there.

BTW not sure how any aftermarket exhaust could case check engine light since they do not affect the stock exhaust manifolds and primary cats that have the O2 sensors.
 
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