DIY Exhaust Mod – Gain of 10+ HP!!!
 

DIY Exhaust Mod – Gain of 10+ HP!!!
10+, I wish, LOL, but it sure does sound better :)

I’ve thought about doing the PSE mod for a while now, but after doing some research I thought there was a cheaper and easier way, so I tried it.

My theory is this. The inside of a 986 muffler has the exhaust going from chamber to chamber before exiting, what if I could decrease the amount of chambers?

See image below, the RED is the where the exhaust comes in, and then it goes to AQUA, before existing via the TAN.
My mod is allow fumes to exit much faster by opening the exit pipes to the first chamber, see the GREEN line.
http://lh3.ggpht.com/_9sTq_sN1KDw/Sa...r_cutaway2.JPG
Below are directions what I did. Let me know your thoughts:
http://lh3.ggpht.com/_9sTq_sN1KDw/Sa...2009%20001.jpg
Take the Tips off:
http://lh5.ggpht.com/_9sTq_sN1KDw/Sa...2009%20002.jpg
Tool needed, I used a ½ inch drill bit:
http://lh3.ggpht.com/_9sTq_sN1KDw/Sa...2009%20009.jpg
Now drill away:
http://lh6.ggpht.com/_9sTq_sN1KDw/Sa...2009%20010.jpg
Both sides should be drilled into and then would look like this:
http://lh6.ggpht.com/_9sTq_sN1KDw/Sa...2009%20004.jpg
2nd Pic
http://lh4.ggpht.com/_9sTq_sN1KDw/Sa...2009%20003.jpg
Install Tips back on, after cleaning of course…and enjoy the new throaty sound without the deafening/annoying drone!!
http://lh3.ggpht.com/_9sTq_sN1KDw/Sa...2009%20011.jpg
I guess one could try larger drill bits and it would get louder, but I’m sure there’s a point before the drone comes into play.
I don’t have a sound file of the before, but here is the after for your hearing pleasure:
http://www.youtube.com/watch?v=RfRErzkyqNc

Thanks,
Cesar

I have done PSE mod on mine, maybe i should try to do this as well to compliment PSE and if it doesnt work i could weld it back up

Now this is a great little mod. Probably took all of a half hour, right?

I cannot tell from the video just how much louder it is, but it does sound "throatier."

Give us your opinion as to how much better it sounds. Do you still long for a different muffler that's louder if you could get one without the nasty cabin drone?

30 min if that!! I'm wanting to drill wider to make it louder, but scared there might be drone past 1/2 inch. I'll post some more clips tomorrow on how loud it is, but I'd say it probably increased it by 10-20% at the most. Not as loud as PSE for sure, but better than stock.

:cool: :cheers:

Hi all,
Below are some more clips I put together this mornig. I'd say the increase sound is anywhere from 10-20%, not huge, but then again, I only used a 1/2 drill bit. You hear the throaty sound more in the lower RPMs.

Boxster Exhaust Mod - Outside #1
http://www.youtube.com/watch?v=Dt0p0etZt7s

Boxster Exhaust Mod - Outside #2
http://www.youtube.com/watch?v=3uQYZj2xUfE

Boxster Exhaust Mod - Topdown
http://www.youtube.com/watch?v=EDGR78lMLF8

Boxster Exhaust Mod - Top Up
http://www.youtube.com/watch?v=GOumu9oH1pU

Thanks,
Cesar

How did you prove it added HP?
 

And at what RPMs?

Butt dyno doesn't count, BTW.

signed
the resident skeptic

Mike,
I promise not to rev it by your house...lol

It's not that loud, it's 1/2 in hole on each side, perhaps an 1 inch whole would be better, but what if then there is drone in the cabin at crusing speeds, which I've heard first hand and hated.

As for the RPM ranged...you saw the distance I drove to and back, but I would guess between 3-5K. Standing still ones probably went as high as 7K.

This is meant to be a inexpensive hack, I'm not about to fork out $$ for a dyno to prove skeptics. If you are skeptic, don't do it. I'm not selling anyone anything, I have no agenda, other than having fun with my Boxster and sharing the experience with others.

Thanks,
Cesar

******************** i like this idea.. now for my question i have the oval shaped exhaust tip.. does that just come right off ? like is it held on with a screw.. as i have not been underneath the car to know and it is also 12 degrees out with snow on the ground so not sure i am going to venture going under the car right now...

I think this exhaust tip configuration varies by year. Beside the obvious single vs. dual. Mine is a 2000 S, the inner tip extensions appear to be welded to the muffler and the outer polished tip is screwed in AND tack welded. So to do this mod i need a really long drill bit and it would also be hard to get the correct angle to drill into the side.

That's correct. I think the tips were removable starting in 02, so anything prior is welded on and you'll need an extra long drill bit.

All mufflers still had the two pipes exiting, so two holes on each side will still need to be completed.

we need to get someone with a 2.7 who has the "pedro" mod to do some side by side sound comparisons.. :)

I wonder how much louder the pedro mod would be.... your mod seems to be almost the same thing... instead of adding plumbing to the outside - to route exhaust gas around the outside of the muffler, you are instead, letting it just bypass many of the internal chambers - and get out much faster - which is essentially the same thing....

i have a 2.7 2000 - and from listening to your youtube clips - the sound is a LOT different than just bone stock. it sounds louder and throatier. I like it! and it's FREE!!!! i wonder if you can "undo" it if you got sick of it???

what you need to do is find a way to put a "plug" or a bung on that hole - so when you take the wifey with you - you can just "plug" it...and make it sound like stock.. kinda like a cheapo bypass valve... open it for most of the time, and if/when you need to be super quiet...you plug it up.

i wish you lived closer to me, I want to hear it.

hey, in that video when you rolled by i got a nice shot of your yellow calipers. I like 'em!

So i have to get the tip removed and drill the holes ..then have the tip welded back ..Or is the any way i can do the holes without removing the tip?

Started this last night, finished up this evening on my '03 non-S boxster.

The oval tip comes off by removing one 13mm bolt.

I used a 7/8" tapered bit, so the holes I wound up with are quite large - 7/8" by about 1.25 or 1.5" because of the angle at which I drilled.

I have not had a chance to open the throttle up properly - rolling on my spare right now, as I picked up a nail on the way to work today - but once I get a proper tire on, we'll see how it sounds. It currently reminds me of the Injen catback I had on my Tiburon, which I loved dearly.

The best part about this 'mod': if you hate it, pick up a used Boxster muffler for $50. :D

So, no drone with the 1/2" holes?
Really, though, this mod is quite easily reversed.
Thanks for posting the clips.

are you sure that is true about the oval tip as my car is a '97 and i am getting from alot of people that it is welded on and not screwed on.. and i have looked at pictures of mufflers from different yrs and some have the bolt and some looked welded on

Yours are welded on, you need to buy a long drill bit, but you should be able to do without taking anything off.

http://beta.sears.com/shc/s/p_10153_12605_00966164000P?vName=Tools&keyword=1/2+Drill+Bit

None at 1/2 inch, don't know if 1 inch would have....waiting to see if other attempt and what they think before going bigger, but I do want to go bigger!!!

1.5 inches, wow! You have to post some clips!!!! How does it sound just reving it in park?

Video clip, as requested.

There is definitely a difference. My tires are once again holding air, so I went for a drive. There is some resonance at ~2900RPM, but it is not 'drone', and it's only noticeable for a range of about 100 RPM either side of 2900. Most noticeable difference is at low RPM - just sounds a little meaner.

I like it. I paid $600 or so for an Injen exhaust that didn't sound appreciably better than this.

The drill bit cost me less than 30 bucks. Not bad, considering how many people I've seen drop a thousand dollars on an exhaust they wound up hating.