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.

sounds awesome.. i got to do this mod.. I am just afraid that i am going to run into a problem since my exhaust tip is welded on and I won't be able to get the right angle with the drill bit. The extra long drill bit might work but not sure..

I propose that Crios gets to name this mod - all cool mods have catchy names that sounds better than "I drilled two holes in my muffler."

Suggestions:

Crios Bilateral Exhaust (CBE) mod
Center Baffle Bypass mod
CTA exhaust mod (cheaper than aftermarket)

Others?

CDM Crios Drillout Method

SD, this is a WONDERFUL idea! I'm so glad you thought of it. Crios deserves to go down in history as the guy who came up with a totally cheap and easy way to make a factory muffler sound better without removing much of anything to do it.

I may just try it on my non-S muffler.

LOL, I guess I better start writing that speech for this year's Porsche Parade in Colorado. :dance:

http://pca.org/paraderegistration/as..._2009_logo.gif

Thanks guys! Just keep mod'ing and sharing!!!

last night i had a chance to listen to sd_boxster's car in person.

I took some quick videos of the sound and when time permits I'lll try to upload them. I have to say the sound was pretty good. I would descibe the actual sound as being almost the same as stock in the WAY it sounds, just louder.

I've heard online/youtube clips of aftermarket exhausts, and some of the pedro systems and the sound of the car is "different". some of the pedro exhausts have what I would categorize as a "raspy" sound at higher rpm.

sd_boxsters car did not sound raspy at all. I got a chance to take a quick spin in his car, both with the top up and down. I never heard ANY resonance. When the top was up, I honestly had a hard time telling that the exhaust was ANY louder than stock while we were just cruising.

if you are outside of the car while the throttle is blipped, or the top is down and the car revved up toward redline, ,then there was a noticeably increase in the sound - but again, I'd say it was similar in overall sound to stock, just maybe 20% louder.

i like this because I honestly like how the boxster sounds, I just think it would be great if it was a bit louder.

I could tell it was louder and sounded better but it was NOT objectionable. You will not get dirty looks from the neighbors, and this would easily pass the all important "wife" test. I am almost certain my wife would not complain about this exhaust - which many of you will understand / appreciate. :)

I am now VERY tempted to try this on my car. I was staring up my exhasut pipe wondering how long of a drill bit I am going to need...as I have the older style welded on tip - it won't be quite as easy, but I still thinkI can do it. I can see the exhaust pipes inside there, I just need to figure out how far/how long of a drill bit I'd need and exactly what angle.

does anyone know if there is any difference internall between a 2000 muffler and the 2003 mufflers that are on crios' and sd_boxster's cars???

I am in the same problem as it would be a different angle to drill the muffler since i have the welded tips even with the extra long drill bit.. i have a little torch do you think it would be easier to just remove the tip and the re-weld it. and could i just screw the tip back on instead of welding it back?

Just wondering if there are any HP, Torque gains, or losses from this mod....Keep in mind the internal bafflings are there NOT just for sound but to promote efficient backpressure for optimum HP gains...Probably ask Mr. Raby to do some study on this mod.

i'd be suprised if two little holes make a whopping difference in back pressure - sufficient to lose power. i think the little holes just let enough extra sound out to make it "noticeable"....

but what do I know... I'd love to hear from an "expert" if any of these "DIY" exhaust mods add or lose power - my guess is that they do nothing detectible except make nice sound.

clb0099-

i am in the same boat as you - I have a welded on muffler. on the cars with the welded on oval tip - if you look *WAY* deep inside the tip - you can see that there are actually TWO separate tubes that essentially join together at the tip - if you look at the picture that crios posted - of the muffler which is opened up /cutaway - you see two distinct internal tubes - and at the exit where they turn into tip s- there is at least an inch or two of space between them - hence he drilled toward the center of the tips - but on OUR Mufflers, there is NO space in beteween those tips.

if you drill "inward" like he did you just drill into the other tube...and it won't work.

i am tempted to drill the opposite direction - OR just drill straight back. i can actually see the "bend" in the back of my tip.... if you shine a flashlight straight back, you can see the tube bend toward the outer portions of themuffler... much in the same way that the cutaway picture shows...it's just that they start much closer together..so you can't drill inward...you need to either drill upward, outward, or just drill in the very back and punch through that way.

i have a very very long drill bit - almost 12" long and it easily reaches that back portion.

i'm very tempted to just start drilling right now. :)

Do it! That's what I did. :D

Installed headers today. Wow - it is MUCH louder. Wonder how the wife is going to feel about this. :D

what kind of headers?.. the ones from ebay?

I picked up the MaxSpeed headers that Rareair was selling. I grabbed 'em from Rareair this AM, installed this afternoon, drove around more this evening, and just finished reinstalling the stockers.

Lots of loud - more than I want. It definitely sounded awesome, but over the top for my tastes. So I'll be reselling 'em...

It was worth a try for the $75 Rareair was selling them for...

do u have a clip of how they sounded.. and i am doing the pedro mod myself ..

I'm impressed - you installed headers, then took them off and resintalled - all in a day. not bad!! I think that is a job that is over my head.

well I took the plunge and I drilled into my muffler and did the "crios" mod.

I just took it out for a quick spin but didn't have time to take any video. My initial impression is that it is a little louder/ throatier at upper rpm, and a little louder at full rpm. I notice more of a change at low rpm than I do at higher rpms. overall the change is not drastic.

I will drive it around like this for a week and see what i think. It was pretty easy. the drill only took about 10 seconds to punch trhough each side. I started with a small bit - a 3/8" and honestly - nothing changed. that hole was too small to notice anything. I then used a 1/2" bit and opened up the smaller hole into a 1/2" hole. when I fired it up after THIS hole, then I noticed a louder sound at idle. at low rpm....you notice it's throatier. like if you were just rolling through a parking lot, you can tell there is a bit more depth to the sound.

immeidately after I did this, and I took it out for an initial spin - one thing I immeidately noticed was the possible thought that i lost low end..... I can't say for sure, but I am wondering if I lost a bit low low end power by doing this.....it may just be all in my head, because of people saying how a high flow exhaust can cause you to lose low end...but one of the first reactions I had as I drove away froma stop was "did I lose soem low end power"....so the next few turns I took, i hammered the gas, and I can't say that I thought it was any slower...

it clearly is NO faster...and I don't think it's any slower....but can anyone suggest their thoughts - could this mod cause you to LOSE low end power?

I'll drive it around for a week - see what I think. I figure if I hate it - I can always tell my wife I broke the muffler and now I NEED to buy afull Fabspeed sytem...

hahahahhhahhha.

i htink she'll tell me to just sell the car... . :)

Without a Dyno, it would be very hard to notice a loss or gain.

To me, my car seems "faster" as it is simply "louder".

I'm into enjoying the way my car sounds and drives around curves, and not so much the actual seconds it takes from 0-60 mph. If this was my concern I woundn't have a spare tire, heated seats or a Bose system in the car :D

My suggestion, if you like the sound then enjoy the mod. :dance:

Some more sound clips, theses taken with professional equipment:

http://www.ppbb.com/boards/ppbbphp/showflat.php?Cat=&Board=ARCHIVES&Number=1480272

http://www.tripdevice.com/bryan_temp...k/IMG_4734.JPG

Drilling straight back with extra-long bit
 

What happens if you drill straight back and only penetrate the relatively narrow space of the central outer shell, missing the inner metal tubes? The result is an opening both through the exhaust tips and at the rear outer casing of the muffler.

Good? Bad? Little or no difference?

I have opted to do the pedro mod on my exhaust..... i like the sound it gives the car.. since i am spent so much money on mods of my car I figure while it is dismantled to just get it done they way i like it so i am happy with it.

Are you running OEM Headers and Midpipes with all cats intact? Just curious.

I just got a new OEM S muffler on Ebay so I may try this with my current muffler to see how it sounds with my performance headers and secondary bypass pipes. Might get too loud.

I tried the mod with a 1/2" bit. The largest I have. It did make a little bit of an improvement. Impressed for 2 mins worth of work.

What do you think would work better. Expanding the hole with a larger bit or maybe drilling another couple more holes in the pipe? Or would both accomplish the same task?

I'm glad you like!!!!

Add a second 1/2 to each side to make louder.....here's a thread on this:

http://www.ppbb.com/boards/ppbbphp/showflat.php?Cat=&Board=ARCHIVES&Number=1487599

Sound clip:
http://www.tripdevice.com/bryan_temp/ppbb/cse_exhaust_hack/cse_exhaust_hack_long_4holes.mp3