DIY Exhaust Mod – Gain of 10+ HP!!!

[Violinman]

For those in the UK that feel the factory standard exhaust is a little too subdued, Hayward and Scott do a superb "bypass" modification which replicates the factory switchable sports exhaust tone -

Porsche 996 and 987 Boxster Stainless Steel Exhausts - Hayward and Scott

You can either drive your car to them and have your existing backbox modified or send them another backbox (like I did) and they mod. it and send it back in a few days ready to be fitted. That way you get to keep the original just in case you or the next owner don't like the finished result! The sound is gorgeous, rich and rumbly but no resonance or droning at cruising speeds. Really reasonable cost as well compared to other sports exhaust options.

[SKOOSH1970]

Carried out this mod yesterday and took her for a blast this morning, can't say the exhaust is much louder but there's definately a frequency change, noticeably below 3000 rpm, almost BMW note to the exhaust, especially a 3L beemer..... went to 13mm diameter on both sides with no drone and the ocassional blip and fart on overrun......what a ******************** to get the tailpipe bolt off from underneath...... she's a 2.7 so not welded on...pretty pleased overall

[Giller]

Originally Posted by SKOOSH1970

Carried out this mod yesterday and took her for a blast this morning, can't say the exhaust is much louder but there's definately a frequency change, noticeably below 3000 rpm, almost BMW note to the exhaust, especially a 3L beemer..... went to 13mm diameter on both sides with no drone and the ocassional blip and fart on overrun......what a ******************** to get the tailpipe bolt off from underneath...... she's a 2.7 so not welded on...pretty pleased overall

You're pleased you made your Porsche sound like a Beemer? Isn't that a step backwards?

[Slate 01]

Originally Posted by Giller

You're pleased you made your Porsche sound like a Beemer? Isn't that a step backwards?

He's working his way up (or down) to the exhaust note of a HOnda Civic with the tomato can muffler, lol.

[particlewave]

This is a great mod. Sounds great and no drawbacks.

Don't take it personal, Skoosh.

[silver-S]

I finally got out the extra-long drill bits and gave it a try. I went with 3/8" holes (9mm) because that is the largest reamer size I have.

The effect is subtle but pleasant. I can now hear some engine noise over the whine of the belts and transmission, but it's nothing the neighbors are going to complain about, or even notice. I'd say I got 10dp (dogpower) increase, max. Maybe.

[benstaples]

I was wandering if the "angle" of the hole makes a difference in the sound. Such as bending the lip nearest the rear inward to catch more exhaust. Thought maybe that would help a smaller hole (avoid the drone) pick up more exhaust consequently more sound? Anyone tried it??

[tommy583]

I have drilled a one inch hole in both sides and have NO hint of a drone.

[Specwar]

I drilled used a .50 bit and then opened it up a bit more to around .75 inches.
Sounds great I don't know about the HP but it leaves things "stock" visually for the CA smog test.

[Dzl210]

Only difference I notice is below 3k rpms and it's a drone. I'm not personally a fan of this mod, but gave me something to do this afternoon.

[silver-S]

Dzl210, that sounds good -- sporty but not obnoxiously loud. What size holes did you make?

[KRAM36]

I did this to my car today, except I used too long of a drill bit and went all the way through the muffler.

Actually sounds pretty good lol

[tommy583]

Wow that must have been a long bit

[KRAM36]

Originally Posted by tommy583

Wow that must have been a long bit

Wanted to make sure I got far enough into the muffler lol.

Craftsman 1/2 in. Extra-Long Drill Bit - Tools - Power Tool Accessories - Drill Bits

[tommy583]

How long is it? I used a multi bit on a 12 inch extension and had just enough length to drill the hole. Are you saying you went thru the pipe and out the muffler somewhere?

[Nine8Six]

Originally Posted by tommy583

How long is it? I used a multi bit on a 12 inch extension and had just enough length to drill the hole. Are you saying you went thru the pipe and out the muffler somewhere?

Just borrow your wife's 45 magnum mate, does the same trick

A mod done in 0.0023 second

[KRAM36]

Originally Posted by tommy583

How long is it? I used a multi bit on a 12 inch extension and had just enough length to drill the hole. Are you saying you went thru the pipe and out the muffler somewhere?

Yep, I sure did. I was counting the number of times the drill bit would hit metal after cutting after the first opening. I figured 3 times would be it. Didn't realize til afterwords that you actually go under the first pipe in the picture.

I got my 3 hits, right out the backside of the muffler.

[sjbox]

The tip on my '02 non-S Boxster is welded. I got myself the extra long 1/2" drill bit from Sears and managed to punch a hole on one side with a long screwdriver but just couldn't get the 1/2" bit to bite The screwdriver hole is shaped like the screwdriver's flat end and the drill bit wants something circular so no go (and, I am not very skilled at wielding a drill).

Tried to drill a pilot hole with a smaller bit and broke it and then couldn't find the broken end!! Hope it doesn't shoot out like a projectile on the freeway.

Maybe I need to get a smaller extra long drill bit to first drill a pilot hole?

[KRAM36]

Originally Posted by sjbox

The tip on my '02 non-S Boxster is welded. I got myself the extra long 1/2" drill bit from Sears and managed to punch a hole on one side with a long screwdriver but just couldn't get the 1/2" bit to bite The screwdriver hole is shaped like the screwdriver's flat end and the drill bit wants something circular so no go (and, I am not very skilled at wielding a drill).

Tried to drill a pilot hole with a smaller bit and broke it and then couldn't find the broken end!! Hope it doesn't shoot out like a projectile on the freeway.

Maybe I need to get a smaller extra long drill bit to first drill a pilot hole?

Muscle, you have to use muscle to keep the drill bit from bouncing around. My drill bit was bouncing around and I just laid the muscle to it. Just don't go all the way out the backside like I did lol.

[01BOXYS]

I just want to clarify that you just need to punch a hole in the same position as Crios and Particlewave mention then using the drill bit step up to the size you want to achieve? You don't have to drill any further into the muffler than just the hole?