dak911

Still "pondering" the Gundo Hack
What size "connector pipe did you use?
Are you happy with it?
Too soft. too loud?
Local shops want about $300 to do it...does that seem high?

z driver 88t

RE. Pricing - I have not seen anything new on this lately. There are several posts that are a few years old indicating shop costs of less than $100. I presume this means you bring them you muffler. Obviously labor costs will be higher if the shop has to pull and remove both mufflers. Some posts indicate mufflers can be removed with the rear bumper cover on, but most indicate it is much easier with the rear bumper cover off. So all that together can tack on a couple hours of labor.

RE Size - I think I've read threads with ranges from 1.25 to 1.75. The 1.75-inch seems to leave very little room for error in terms of clearing other components when putting it back together depending on your routing.

I had some concerns over the potential loss in torque in the lower RPM range by going with too large of a bypass pipe. I've seen a number of dyno plots with guys running straight pipe muffler bypass systems like those from Fabspeed and the result seems to be a nominal increase in top-end power with a significant loss at the bottom end. I've never seen any dyno plots of Gundo hacks using different size pipes - it may be negligible - but in my mind, going to too large of a pipe starts to put you in that scenario. This is just my theory - no testing involved.

With all that in mind I planned to duplicate this set-up using a 1.25 inch pipe. It's on the small side, but I tend to err on the side of caution and the post indicates it made a really nice improvement in sound - which is really all this hack is good for. There are several audio clips on this thread that you can download of before and after.

https://rennlist.com/forums/996-foru...haust-mod.html

I've ordered some used mufflers on EBAY and a mandrel bent piece of 180 degree, 1.25 inch pipe (like the one shown in the link above) last week that are supposed to arrive tomorrow. I'm hoping to have the Gundo hack done next week and install them by mid-May. I'll report back in a separate thread with pricing and impressions once I do.

twitchett

Just had mine done. I had mine done for $260 CAD and I think they did great work. Car sounds excellent! I used a 1.5" pipe and everyone on the Canadian forum said I was crazy for not going 2". Either way, I prefer the higher pitch at high rpms I get with 1.5".

Here is the work I got for $260.. no messy welds like I have seen in other cases. I believe this is the Fister style rather than Gundo, but I figured it was relevant enough.

rockhouse66

I had the Gundo done with a 1.5" diameter pipe. I believe the Gundo is more work than the Fister, since you have to cut out that "blank". I think the sound is perfect. Very quiet at idle and cruise, no drone, but a nice robust sound on acceleration.

parris

I had the gundo done and I barely can notice the difference with the stock sound. A little louder at idle, but not much more than that.