How restrictive is the stock boxster muffler?
 

from the looks of it it has to go through 3 chambers before it exits through the tail pipe that seems like a lot of looping around for no reason. I guess they do this to not only restrict exhaust flow but to muffle the sound a little. Gains from just bypassing the muffler or straight piping it looks like it would free up some horsepower.

The stock headers (or exhaust manifolds) all the way to the tail pipe is a realtively small distance, this makes me think that porsche did this on purpose to muffle the exhaust and the flow otherwise it would be too loud or too efficient in exhaust flow.

I've thought about doing the Pedro sport exhaust a little differently, there's a guy that will do the exhaust work for me for a decent price. I was thinking maybe putting something into the stock muffler inlet to lessen the flow into the 3 chamber system and allowing it to go straight through to the tail pipe through the bypass pipes.

I'll post pics later i'm at work and can't do it right now but it might clear up some confusion.

Would this be too loud for the street? Would this be a worthwhile mod hp/tq and 1/4 mile times wise?

You bought the wrong car...

:cheers:

Indeed, you bought the wrong car. However, it's your money to waste.
Don't expect any changes cept sound. You also might end up with less hps.

:cheers:

all that was needed was, "it wouldn't make a difference" thanks "you bought the wrong car" was unneccessary. I bought this car for the wife and she wants it to be "zoomy" I fashioned the Technoflo Air intake for her and she likes it. I was thinking about doing the exhaust to give it a more aggressive sound without being overbearing along with letting the car breathe to free up some horsepower.

I already have a modding machine 2007 honda civic Si that i have done a lot of stuff to already so the boxster is not the "wrong car" for me. I'm not going to mod it out obviously i just wanted to do a few things to optimize the performance of the vehicle in it's stock state. I'm not putting a cat-back on it or putting nitrous on it. It's a daily driver that hardly ever sees the track but letting the car be unique in its own right. It's definately a cruise car but if i could effectively free up the exhaust to allow better flow and better sound i wouldn't mind doing that.

however if there are minimal gains from doing this then i would probably just leave it. Thanks for your input anyways

Yes but you mentioned 1/4 mile times etc. hence the response you got.
A worded differently question would have gotten a different answer.

:cheers:

actually I was trying to figure out the same thing. There is a thread on here (see link below) that has dyno'd his car before and is going to do it after to see the HP increase. Some people think Porsche purposely restricted the boxster's air flow to cut down on HP to make the 911 look faster. I am eager to see the out come

http://www.987forum.com/forums/showthread.php?t=21061

My philosophy is a few HP here and a few Hp increase there start to add up!! *(as long as its cost effective) :cool:

The stock muffler flows pretty well the experts say. Just ask Jake Raby or Charles over at LN engineering or search some of their threads. They have done flow tests and dynoed several so called high flow performance mufflers and many lose hp compared to the stock muffler. The main slap against the oem muffler is that it is heavy.

Now that is a great answer, not just an opinion, but supported by facts. Kudos :cheers: I really would like to know if you gain any resonable HP by bypassing or removing the cats. My first car was a mgb ltd. 1st thing I did was take off the cat and put headers on it. it really put some pet in that tiney engine. I have been following some of pedros mods, but he never tells how much hp you gain or even an estimate. Since I am keeping this I want to squeeze out as much juice as possible.

http://www.pedrosgarage.com/Site/DIY%20Projects.html

that's my thread, middle next month it will be dynoed for the last time and exhaust installed. I will post the numbers. I have different opinions on what to expect, which I won't get into here. We will see.

Cool, I saw you were out until august 15. I was thinking, this guy has to get his priorities straight!! :D Just kiddin. Did you figure out why that guy's dyno was so low in registering your HP? As long as you use the same machine and he doesn't mess with it, it should give you an accurate reading of increased HP. Good luck and keep up the good work!! :cool:

Yeah, unfortunately my job interferes with my projects. but it also funds them as well. :) so got to go when they say go. Well, no never figured out what was up with the dyno. don't think it was my car though, you can see the Video of the car that dynoed after me, he is used to putting down over 350 WHP. You can see and hear his car is a beast, he's hitting close to 30 psi boost. this is a quote from him:

"Yeah I thought yours seemed a little low even for a stocker.. but as they said that dyno is stingy. Dunno, mine dyno'd 90hp and 50ftlb down from last time.. "

sorry for the wait, stayed tuned for the results

I got rid of the stock muffler and put on a top speed muffler.

http://www.topspeedauto.com/ProductCart/pc/viewPrd.asp?idcategory=0&idproduct=1781

I really like the sound and that the top speed muffler is lighter and it doesn't turn my rear trunk into an oven. However, It seems to me that the car did lose some hp. I am going to run my iphone application "dynolicious" on the two mufflers and check my suspicions sometime in the next few months.

:matchup:

Just curious, How is an Iphone going to tell you the difference in HP between the two mufflers??

My car dyno'd in the 5-7 additional peak hp range before/after adding the Fabspeed cat bypass pipes. Better than nothing, but not a lot better than nothing. On the bright side they are a heck of a lot lighter and sound cool. :)

Actually I found a good use for the rear heated trunk, It keeps my pizza nice and hot by the time I get home. :D I actually fitted a family size cooler in the "FRUNK" so i can have hot pizza in the back and cold beer out of the front. :cheers:

On the serious side, I noticed modding a Porsche is as bad as when I had my Vette. I found real quickly that you don;t go in and ask for a corvette altenator, you ask for a GM Altenator. I mean come on you can supercharge a frickin miata for around $2000, but to do a porsche your lookng at a starting price of around $7000. :eek:

Now I didn't buy my Box to street race, but when one of those cocky little kids roll up next to me, reving his engine, in his Mustang gt with spinners and walmart radio cranking out nothing but distortion, I would seriously like to at least show him the superiority of finely tuned German machine. :cool:

If you want to outrun a Mustang, get to your closest road course where you have to turn a bunch. You should do pretty well stock vs stock. A Boxster is the the BIG time wrong car for the stop light grand prix.

On the Miata comment, its not really a fair comparison. Ignoring the fact that there are/were significantly more Miatas sold than Boxsters which means there is more market competition, the older model Miata motors were based off a forced induction motor and were relatively low compression with simple engine management. Pretty easy to slap a basic kit on them and not blow anything up. All Boxsters are much more complicated cars than older Miatas are, especially when it comes to the stock engine management, and all Boxster motors are higher compression that don't take too well to forced induction unless you are very careful. However, that being said, price a base Cosworth supercharger (one of the few units available) for a late model Miata which has significantly more advanced technology than the older Miatas.....you are looking $5k+ starting price.

Mufflers can be tricky on our cars, I have tried four different mufflers, stock, two dansk, and one gembella. I think I ran dynos on two of them. Two of them gave a lot of resonance (gemballa, and one of the dansk) , and at least one cost 3+ hp on the dynojet dyno (gemballa), it felt like it was not as fast on the butt dyno as well.

Jake Raby is comming up with more hard data on exhaust systems for our cars one of these days which should be very useful. That being said, if you can get an muffler, or muffler mod that does not have that resonance, and does not compromise performance, the sound is sure makes it seem like it has more hp and is more fun. Hey, remember, this is all about having fun....

Ed

:dance:

BigBorian,

there is an interesting thread by Bill Pickering on muffler tests on the Boxsterspec.com forum. There are some small gains with certain mufflers however it is evident that they are minimal. The greatest improvement to a boxster as far as pick-up and go is to loose the weight. Spec cars drop close to 500lbs... but comfort takes a hit.
That said, there are claims of up to 50hp gains on a boxster S but it involves aftermarket intake, headers, cats/ muffler and ECU remapping...

how bad do you want it?

Mike