EDenney

I'll start with link to the before and after video since some people were missing it at the bottom of the post: (Sorry, couldn't figure out how to insert it into the page): http://www.youtube.com/v/wDwfAt337pY


A number of people have inquired about doing the exhaust bypass mod to their stock C5 exhaust including myself. While it's much more popular to do it with the Z06 Titanium exhaust (Ti's) because they have a better sound to begin with, it's still a worthwhile and very inexpensive mod to do to a stock C5 exhaust to beef it up a little under throttle, while retaining a near stock sound at idle and no noticeable change at cruise.

I've been searching for the perfect aftermarket exhaust for weeks now and I've yet to find one that has the complete package I'm looking for, so before making a purchase I decided to go ahead and do the bypass mod on my stock system since there was literally nothing to lose. I'm fine with the look of my exhaust with the Corsa tips on it, and I have brand new muffler and tips compliments of the insurance company after getting rear ended coming home Christmas night. I'm only looking for a better sound and perhaps a little additional HP, though there isn't much to be gained from an aftermarket exhaust anyway so it's mostly about sound.

Unfortunately not many people had done this mod to a stock C5 exhaust and there was only one video I could find of how it sounded after it was done, so I took a number of pictures and made a before and after video to try and help others who might be considering this. I hope somebody finds this information useful.

I decided to go with a 1.5" bypass pipe and a 1.25" hole, with the bypass pipe mounted very close to the elbows of both pipes. The size of the hole and the location of the bypass pipe relative to the muffler will affect the volume and sound of the exhaust. I really didn't want my exhaust to be too loud or too rough, the one video I saw had a little bit of that motorboat sound to it at idle and I didn't want that, so I went with a slightly smaller hole than some others have drilled. Having done this and hearing the result, I definitely would have gone with a 1.5" hole and I think that would have been perfect.

I should also mention that I had a Borla X-Pipe installed at the same time, just before the bypass mod was done. The "before" video of the exhaust was taken with the X-Pipe installed, and of course the X-Pipe is also on for the "after" video. Other than that my car and my exhaust is completely stock except for a Vararam VR-B2, Corsa chrome exhaust tips, and (irrelevant) C6 chrome reproduction wheels. Note that the small amount of smoke in the video was the residue burning off of the newly installed X-Pipe.

In the end, I definitely liked the sound of the exhaust better, but I'm not sure if I'm going to keep it yet. Total cost for the X-Pipe install and the exhaust bypass mod was $120 at a local muffler shop I like to use. Total time for both jobs was about 2 hours, about 1 hour for each job, taking his time and making sure to do everything right. They only billed me for an hour and a half though. Most of the bypass mod time was spent measuring and fabricating the bypass pipes, the cutting and welding didn't take too much time.


Pics (yes I know my car is filthy :o, it's getting detailed this week):

View of the left muffler before starting the job


Close-up of the left muffler before starting the job


Close-up of the left muffler after cutting the 1.25" bypass hole


Welding the right bypass pipe


Close-up of the left muffler after bypass is completed


View of the complete exhaust system before the bypass


View of the complete exhaust system after the bypass


Just a pic of my finished car

MagneticRed1977

How does it sound compare to before mod?

EDenney

(Edit) I moved the link to the video to the top of the post for those that weren't reading through the post to find the link to the video at the bottom. I didn't know how to embed the video itself into the page so it's just a link that launches the video. You can tell the difference in the exhaust pretty clearly before and after the mod even though it's a short clip. Definitely a difference I could notice after it was done. Nothing but an improvement for sure.

00 Rooster

It sure sounds better. One question though, is it more raspy now? I think it might be an function of the mic rather than the exhaust. I like the new sound either way

EDenney

Not sure if I would describe it as raspy or not. The sound is different depending on the RPMs, and whether it's being revved/accelerating, or holding at a constant RPM. It's a short video and it doesn't pick up everything since I wasn't very close to the exhaust, so I'll say that at idle it sounds a little 'meatier', a little more of a V8 type sound, but only a little bit. When I just start to rev it at idle is when I notice the biggest difference, and you can hear the difference in that rev after the mod in the video. Definitely a little more 'throaty'. At higher RPMs after the mod it seems to me to sound a little more like the Corsa exhaust does in terms of pitch, a little more of a formula/indy type sound. In fact I would say that in all respects this mod brings the sound closer in line with the Corsa.

If I couldn't afford to change out my stock C5 exhaust or if I were really attched to it for some reason, I would definitely do this inexpensive mod and I'd be pretty happy with the results, but I would definitely do a slightly larger, 1.5" bypass hole. I only did this mod though as a precursor to buying an aftermarket exhaust or a set of TIs. I figured for $75 or so it was worth seeing if I could get the sound out of it that I wanted, and either way it would be worth the money. I'm still looking for a little more though, so I'm almost definitely going to get something else, quite possibly a set of TI's and then do the bypass mod to them, which I think would probably be PERFECT with those. Only problem is I don't think my muffler shop can work with Titanium, so I may have to go elsewhere.

screw991le

Before and after of my AA by pass mod clips are below.

The sound depends on where to put the by pass. The farther away from the muffler you go the louder the exhaust gets.

Before

http://s34.photobucket.com/albums/d1...eAAexhuast.flv

After

http://s34.photobucket.com/albums/d1...rAAexhaust.flv

jtkeller

Great job! I did my Ti's and love the sound. I've got a few extra pieces of Ti pipe if there are any Ti owners out there looking.

Osyrepel

So there is no way to know if the x-pipe is creating the rumble, or the mod.. should have done them seperate to make it worth the post. Sorry

damilleniumboy

I did that mood a while back, and it does make the exhaust louder. I have a few clips, but I have been too lazy to upload them to the computer. The exhaust is all stock.

EDenney

The X-Pipe doesn't create rumble, it smoothes the exhaust. That's the whole reason of purchasing an X-Pipe and replacing the inefficient stock H-Pipe, it allows a smoother flow of exhaust between the two sides since it isn't trying to make a 90 degree turn and squeeze through a dime sized hole. I didn't want my exhaust to sound like a motorboat, which IMO is a bit like what some of the stock C5 bypass mods sound like without an X-Pipe. Sorry that you didn't find the post helpful, but for the rest who have junked the crappy stock H-pipe it is.

EDenney

Actually as I already mentioned in the initial post, I only did this as an off handed test before scrapping my stock system and purchasing an aftermarket system, or a set of Ti's and doing the same mod to them. I'm going to be looking at a set on Monday that they're polishing up right now, if I buy them I would definitely like the Ti pipe you have leftover. To be safe I guess I'd need about 6" on each side to start with, do you have that much? PM me and let me know please.

1slowFRC

That little mod really make a pretty big difference on a stock exhaust. Definitely going to consider this due to the fact that a. I'm in college and broke, b. I just bought my car and am paying off the loan, and c. actually like the sound. How far away from the muffler do you think I should go???

1slowFRC

DID the exhaust by-pass mod today and it makes a pretty big difference...I LOVE IT

EDenney

Can't go wrong with it, it's practically somethin' for nothin'. Perfect for a college student lucky enough to have a Vette .

How big did you make the hole, and did you have them inset the pipe at all toward the muffler, or basically mount it as close to the elbows as possible? I went with 1.25" on the hole and 1.5" pipe and had it placed closed to the elbows. I Should have gone with a 1.5" hole.

Please post a video of how your exhaust sounds after the mod if possible, there aren't many around for people to listen to. Everybody pretty much knows what their stock exhaust sounds like before the mod so no biggy if you don't have a "before" video.

Fasthotrod

I did this mod last Friday.

I used 1 7/8" pipe from my local auto parts store. Dropped the exhaust, cut a 'template' out of a cardboard tube from a paper towel roll. Transfered the shape to the exhaust pipe, made some corrections, and welded them in.

The biggest PITA was cutting a hole in the stock exhaust. I used a DeWalt hand drill and a Uni-Bit at first, but I ended up switching to a Dremel and used a few cutting discs to get the job done. The stock exhaust is THICK compared to 'regular' exhaust pipe.

Overall I was pretty impressed. It's slightly louder, has a lower tone, and is a little raspy. Perfect until I upgrade the stock exhaust. (I'll probably go long tubes, high flow cats and x-pipe before replacing the stock system.)

Oh yea... the pipe cost less than $5. Simple, cheap, and easy.

Mark

FASST LN

Thought I would chime in and post a link to my video with the exhaust mod. The second video is the exhaust mod with the addition of shorty headers.

Mine is a 2000 with the stock x-pipe. I have no idea what size pipe they used.

http://forums.corvetteforum.com/show....php?t=1986203

EDenney

Thanks for posting the videos, definitely a difference before and after the shortys. FYI the stock pipe is an H-Pipe (very inefficient), the aftermarkets are X-Pipes (see pics below for a comparison). If you replace your H-Pipe with an X-Pipe you'll get rid of a lot of that "motorboat" sound that IMO is so distinctive with the stock C5 bypass mod with the stock H-Pipe (not in good way IMHO). You'll keep the "good" sound benefits of the mod. Purely a suggestion though, and of course it's all about dollars .

Oh, and don't be fooled by the size of the connecting pipe on the stock H-Pipe. It looks nice and big but the hole itself is only about the size of a dime! That's one of the reasons the X-pipe helps so much, not only because of the X design.

Stock H-Pipe, cut behind the Cats


Borla X-Pipe

EDenney

Kudos . Ironically, cutting the holes was the easiest part for the guy at the muffler shop, took him about 10 seconds per hole whatever he was using. The longest part was fabricating the bypass pieces and welding them.

B-Vette

Nice job you did there, the stock TI is worth keeping (especially the weight factor and cost savings that can be achieved).

I didn't have that option for my 2000. The base stock muffler and H-pipe was a piece of crap right from the get-go and quickly found it's way in to a trash bin.

1slowFRC

Hey I had the hole cut to a little over 1.25" because like you I was using a 1.5" pipe and the guy didn't want to cut it much bigger. I don't have a before sound clip, but I will see if I can post an after clip. I just drove down to Shreveport for my internship and after I get situated I will see what I can do. Also how do you post pictures because I did take those