I plan on doing a custom exhaust on my 07 G35x and have an exhaust shop bend/weld some stainless up for me. My exhaust guy has made all of my exhaust on all 3 of my cars/trucks I have ever owned and does really good work. So why spend the money on costly exhaust systems when I can have him make whatever I want.

First I'm going to replace the Y pipe and see how that sounds. Then if I want more sound I'm going to replace the cats with high flow cats. If I want more after that I will get some magnaflow mufflers and have him complete the cat back. Has anyone done something like this yet? What size stainless pipe should I use?

The reason I'm doing this in steps b/c I dont want it to be to loud b/c its her DD. Plus I have heard videos of Gs that are raspy and I dont want that.

 

Reason for spending a bit of cash more is for the R&D that goes into the parts IMO. Motordyne for example is IMO one of the best exhausts that ive heard in person and also shows fair gains on the dyno.

Not saying custom made wont make it sound good but usually its a trial and error with that. Plus you dont know any numbers until you dyno. Ive definitely heard some good custom made exhausts just for me i'd probably spend the money to get something thats been proven to give great gains and has great reviews Good luck!!

 

Kenny Da Mayor on here had a custom exhaust on his '07 Sedan 6mt, and another friend of mine is running a custom on his second gen and honestly if done right sounds absolutely perfect. Also my first gen is running a custom exhaust with Resonated TP's and I love it.

To answer your question use the stock size tubing 2.5" you can make the outlets for the mufflers a tab larger, but for quality sound usually it's best to stay within stock piping width.

 

Not worried about hp gains right now so really just want it to sound good. Also dont want to shell out $1500 for exhaust system when I can get what she wants for a few hundred. The car is fast enough for her right now.

When I get this car I will get a full exhaust system made from the turbos back...

Tried to search for Kenny Da Mayor with no luck. But I found another Kenny person that started an exhaust thread and never finished. He did post some pics of a y pipe though. I figured 2.5" would be good just wanted to check. Once I take it to my exhaust guy I will update this thread.

Thanks guys!

 

Took the G to get the exhaust looked at today. Man that thing has one of the most restricted stock exhaust systems I have ever seen. Manifolds --> Cats --> Tiny Y pipe --> Resonators --> Mufflers. Most of the pipe is 1.75" but I bet there are some parts where it is less than 1.5". I'm going with a Magnaflow X pipe in place of the factory Y pipe to see how that sounds. This will also make it a true dual setup. I'll get pics and vids up after it is done later this week but here are some pics from today.

 

Couldn't connect the X pipe where we wanted b/c needed to keep the flex joints after the cats. He cut both Y pipes and replaced with a magnaflow X pipe. Wasn't much sound gain so ended up cutting the rear mufflers off and welding the stock tips back on which makes it still look stock. No rasp at all and it sounds really good. Also at 70mph-80mph on the interstate with the windows up and radio off it sounds a little louder then stock with no drone. Later down the road I'm going to do the whole cat back but for now I really like this setup. I'm going to have him order 2 flex joints, 2 resonators and 2 magnaflow mufflers then complete the cat back using 2.25" stainless piping. Here are some pics of what was done today:







video will be up later.

 

Sound clip? People are saying that the stock exhaust sounds better without muffler. Would be nice if you can have 2 sound clips to compare.

 

Don't have a before video but when the exhaust was stock you could not hear the exhaust over the intakes even at the rear of the car. I'll try to get a good video with my go pro in the next couple of days.

 

Here's mine. Only thing done is intake and muffler delete, still trying to figure out what kind of tips I want put on before I visit a shop

http://www.youtube.com/playlist?list=PL0D6B2F9A5A373B83

 

I also have the rear muffler delete with a straight pipe however I am getting a lot of cabin drone, especially between 1700-2200 rpms. At first it was manageable but now it is getting quite annoying. Do you get any drone with this custom setup with the X-pipe? You mentioned you do not at higher speeds but how about at lower rpm's like from a take off?

 

very similar to what i did,,,my x pipe is just a little bigger,, cause my guy " made" it, and just plumbed it back into stock system and stock mufflers,,, actually had pics on here of the job,,, but was from 2 years or so ago.... also NO resonators on my car, and no drone....

 

I am running Megan HFCs with custom 2.5 piping back to 2 Magnaflows with resonators because it sounded hideously loud without them. Now it sounds meaner but not overly loud. No rasp or drone.

 

^^ do you have a sound clip by chance?

 

i love how people look at the stock exhaust and think its so restrictive. Like Nissan/Infiniti didnt spend months and/or years developing and testing their systems for efficiency

 

The stock Y is very restrictive--two pipes get pancaked into one. Infiniti cares more about excessive noise than performance in the sedan. Even going back to my Maxima days, you could extract a sizeable amount of power with the down pipe (what we called a Y pipe).