DIY Exhaust Mod – Gain of 10+ HP!!!

[Michiganstar]

Originally Posted by Homeboy981

Cat Back System is a better responding and sounding way to go!

IF you have to do it, and when I was a newer member I did, use a metal punch from Lowes for shipping cement. I found a 1" version and made the holes within a few minutes. No stuck drill bits. For a couple hundred bucks you can chunk the "boat anchor" and get a really cool sounding exhaust…instead of a faint glimmer of one!

Anyone want a boat anchor with a Crios mod?

I will no doubt go for a cat back system at some point but this mod is perfect for those who want a stop gap or dont want to lose the original parts.

[mangoman]

Originally Posted by Michiganstar

3yr old thread resurrection!!

I have just completed this mod on my '03 S and I'm really pleased with the results. The facelift exhaust/combo mean that you have to go in at quite an angle but its still easy enough. I had difficulty getting started with the large drill bit so I went with a smaller one to get the hole in place then went up a few sizes and on the 2nd drill and finally went with the large drill bit and it went through first time.
Really pleased with the throatier sound at idle and also there is a noticeable woofle at around 2800rpm. This is all achieved with no drone at highway speeds. Well worthwhile mod to do IMO.

What about the MOT emissions test? Did it pass?

[sub5kvm]

Originally Posted by Michiganstar

3yr old thread resurrection!!

I have just completed this mod on my '03 S and I'm really pleased with the results. The facelift exhaust/combo mean that you have to go in at quite an angle but its still easy enough. I had difficulty getting started with the large drill bit so I went with a smaller one to get the hole in place then went up a few sizes and on the 2nd drill and finally went with the large drill bit and it went through first time.
Really pleased with the throatier sound at idle and also there is a noticeable woofle at around 2800rpm. This is all achieved with no drone at highway speeds. Well worthwhile mod to do IMO.

Hi Michiganstar
My Boxster is a Facelift S also. Im looking to make this Mod, just interested to know if you drilled just through the end pipes only or through the other pipe in the middle chamber too (as in the picture shown by the green line)?

Ive already done the "de-snorkel" mod but looking for a little more grunt, without going down the by-pass or replacement route.

Im also from Reading too btw!

Cheers

[smygolf]

I have a question regarding the size of the holes.
Now i have around ½", if i go up to 1" does it affect the rpm range where i can hear it?

[germaneighter]

Did the crios muffler mod to my '02 2.7 today. I used a long 3/8" drill bit for initial hole and then used a carbide die grinder bit welded to an 8" piece of 1/4"dia bar stock that would fit my air die grinder. Made an oval about 1/2" X 3/4". I really like the mild sound difference plus I do think it added just a touch to the bottom end to mid range. thanks crios....

[valiantechoes]

Another happy camper! Thanks crios!!

I did the drill mod on my 2003 Boxster and ended up using a 7/8" drill bit as final hole size. I did not have a 1/2" for my heavy drill. Worked as desired with a nice low growl at low RPM"s but no noticeable droning or noise increase at cruise RPM with the top up. I did have to use a cold chisel to start the hole for the drilling and had to step up drill size to make the final hole.

Changed exhaust tips to the two round S type to go with the new sound.

Great Mod!!

[CrashTest]

I know this is an older thread, but I just picked up a 98 2.5L and immediately removed the snorkel and put two ovalized 9/16" holes in the internal muffler pipes as described here. So glad I did. The muffler modification is subtle, mainly deeper and louder right off idle. The snorkel removal is a must. 5000rpm and up is spine tingling now.

I will probably be doing the Pedro's/PSE partial muffler bypass in the near future to give a little more exhaust noise.

[nquintans]

Another Happy User!! Thanks Crios!

It just took me 5 min to make the holes in a '99 2.5 Boxster, and the change is great! I made two holes of 1/2 and the sound is great at idle, a lot better than stock! Did have a chance to try it on the road but it doesn't seem to be any ressonance.

I'm glad i did it!

[chipmunk]

1 inch is quite a big hole. How does it sound?

[particlewave]

Slate - I put this off for the same reason. I finally wound up doing 9/16" holes about 10 months ago. The sound at idle is much deeper and throatier, and a general increase in roar over the RPM range with zero noticeable resonance. Overall, I'm very happy with the sound. I'm even considering enlarging the holes to 1" to get just a little more growl out of it.

I don't think there's much chance of getting a lot of resonance or that annoying "coffee can muffler" racket since you're only bypassing one chamber

[JAAY]

1" sounds glorious. No drone or resonance at all. I may take the car out tomorrow. I'll try and post a video. Stay tuned.

[chipmunk]

OK - here is the sound of the exhaust with 10mm, 13mm, and 15mm holes. Subtle difference in sound - the 10mm is a little more raspy and the 15mm a slightly deeper note. If you go larger I would image it will get even deeper.

Porsche Boxster 986 Crios Mod - YouTube

[jb92563]

Based on the great results I had when I installed the 2nd cat delete pipes on my top speed muffler, im thinking that doing the 2nd cat delete pipes with the stock muffler may also produce the great improvement in exhaust tone and throttle responsiveness.

Has anyone tried that?

[silver-S]

chipmunk, looks like your AOS is going bad.

Thanks for doing the controlled test. It's great to have direct comparison data like that!

[chipmunk]

That's steam - it was less than 2 degrees outside. Although that said, it did smoke when I started it up for a run earlier in the day and I have started to wonder about the AOS - from what I can see it's an easy enough job to do so may give it a go myself.

[JAAY]

Here ya go 1" holes. The password is 986 to watch the video.

[chipmunk]

That sounds pretty good - I am sure that you can hear it when you open up on the road too.

[JAAY]

Yea, you hear it, but no drone at all.

[Benjamin]

I'm a little confused as to why the holes need to be at such a steep angle where lots of people are having trouble getting the hole started. Isn't any place you can reach on that pipe still in the same chamber and would produce essentially the same results? Why not shoot for deeper in the pipe where the angle is much shallower and easier for the drill to start?

[chipmunk]

I see no reason why you can't drill anywhere along the pipe, as long as you are still within the middle compartment and your drill bit is long enough. I drilled roughly in the middle of the bend. I first created a notch with a screwdriver and then used a 6mm drill and worked up.

For info, I have just ordered 20mm and 25mm drill bits and will be amending my video so you can compare the difference in sound between the smaller (10mm, 13mm, 15mm) and the bigger holes.