I just took out a 2 1/4 inch section of the factory pipe curve. Left part on driver's side and Rt. part on passenger side, just beyond the inside of the weld seam, and just hit 0.9 Bar for the first time ever with NO other mods (except I do run a toluene/91 pump gas mix). 88 degrees outside. It is not loud at all and has ZERO drone. I can feel the difference instantly. I love the exhaust tone. The removed section is 1 3/4 wide and 2 1/4 long oval. Thanks to 6speedonline and the risk takers who "invented" this easy mod.

here is the link:

https://www.6speedonline.com/forums/...ler-996tt.html

hilar ioush ilarious

 

Glad you like it! What's next on your mod list?

 

EPL tune is next, then I'll see if my clutch brakes or not. I'll be needing some rear tires pretty soon too. Then plan on upgrading injectors, diverter valves, 4.2 bar fuel pressure reg., maybe billet turbine upgrades, intake, plenum, meth injection, Real exhaust, intercoolers, ect, ect, ect,. It really never ends, does it?

 

Good stuff! It seem to never end! I know I keep thinking of things to do!

 

I'm amazed drilling a hole like that would give you noticeable power gains. You still have cats? I would think those would be the limiting factor.

 

I think bypassing the massive secondary cats is where most of the gains are coming from. Sound perfect too. I'm happy.

 

If you have done that mod, you haven't bypassed any Cats at all. what you have done is partly bypass the internals of the muffler and reduced some back pressure from inside there. That mod is good for a standard car, if you want a bit more performance and a better/louder sound.

If you get into changing out Turbos and Injectors your going to have to ditch both those cats and get a decent sports exhaust. I have a Miltek 100 cell motor sports exhaust and is great. But Markski's X flow system is gaining more and more respect over here in the UK.

Bottom line, if you want to take tuning your car seriously you must get a decent exhaust.

 

This picture is from the original post about the mod. It it was posted by the op of the mod. It shows clearly the 2 cats one in front of each other, then the diffuser plate attached to the end of the second Cat, then the hole in the bend of the tail pipe.

As you can see, the exhaust gasses have to pass through both cats first, then a percentage passes into the muffler and the other percentage through the modded hole in the pipe.

 

want to do it
any more photo ? what tools I need?
thanks

 

As you can see above it is on my to do list, but for now I'm happy. If you want to give me an exhaust I would be more than happy to install it. LOL I'm proud of you for your set-up, but I have only owned this car a few months. I most definitely take my set-up/ "tune" seriously, but I do not have piles of money laying around to be able to do all the things I want all at once. I will get there soon enough. as you may have read on the forum, this mod does add HP and TQ, and sounds way better than factory. It cost me like 40 bucks. If I could buy a full 3" through exhaust for 40 bucks, I would have done so. 40 bucks for about 20 Ft. Lbs of extra TQ is not bad. To imply I'm not taking my tune seriously is an insult.

 

NO No no please don't take it as an insult. I meant it as the way to go if your having some big mods done. What I was trying to express is that the hole wont do it for some real power upgrades. So a big hearty sorry for Scotland if you took it as an insult. If you read a few more of my posts you will realise I don't do Intentional insults. So sorry again for any implied insults.

The biggest restriction in the exhaust is the cats , the hole /bypass is in comparison to the cats is only a small back pressure relief. I got interested in the original post because I was thinking about doing the same thing. I even cut my complete exhausts in two and removed the cats and internals, but I decided to go for the miltek because the gain was more tangible.
I understand money constraints but please remember there is no comparison between the bypass hole and a 100 cell sports exhaust. I really noticed the difference. My advice, do the hole mod but save up for a decent exhaust it will pay off in the end.



PS don't forget you haven't bypassed either of the two cats, there still a restriction.

 

I used a 1 3/4" hole saw with an extension. I removed my exhaust tips, made the drill bit extend out as far as I could to get a bite, and then decreased the drill bit depth as the hole saw started to bite in. You need about a 7.0amp drill because its hard to drill through, I then used a grinder on the same extension to smooth out the hole. Took about 30-40 mins total. Here are some pics:

http://i424.photobucket.com/albums/p.../exhaust12.jpg

http://i424.photobucket.com/albums/p...t/exhaust4.jpg

http://i424.photobucket.com/albums/p...t/exhaust7.jpg

http://i424.photobucket.com/albums/p...ecutter1-1.jpg

http://i424.photobucket.com/albums/p...t/exhaust5.jpg

http://i424.photobucket.com/albums/p...dextension.jpg

 

My bad. I knew there was a second cat, but did not know it was directly after the first. I guess that's why it's not too loud. The multiple exhaust bends must be very restrictive. I hear one 90 degree bend is as restrictive as 40 feet of straight pipe, and it looks like this mod eliminates 4 90 degree turns..well the first bend is probably still causing some significant turbulence. woosh did a dyno after this mod, and he proved it does at least help, for nearly no expense. I have a good friend that is a fabricator that is going to build me a complete exhaust that he claims will be better than anything on the market....He has a big head, but really is an amazing fabricator. He has many things he is working on at the moment, so I will have to wait. This is a pacifier, but much better than I was expecting.

 

No hard feelings. I have 3 cars that I'm modding and have my 300ZXTT running 25 lbs of boost and making huge numbers. I have 615HP on that, and it started with 300HP factory. I did a full engine rebuild with all race internals, and have upgraded everything. cams, heads, turbos, downpipes, full 3" through exhaust, injectors, manifold, intercoolers, radiator, oil cooler, electronic boost controller, wheels, tires, suspension, cam gears, custom leather interior, custom fabbed dash face so I could add GPS/DVD, gigantic stereo system, mild ground effects, clutch, flywheel, driveshaft, Drove all the way to LA Cali for my tune from the best, and I'm sure I'm forgetting some other things. I need larger injectors, and larger intercooler piping at the moment. It took me 7 years to build, and parts are 1/8th the cost of Porsche parts. My entire car has about 20K in it, and has much more power than my 996TT. Give me time... My long-term goal is to get 800HP out of my 996TT, but it will take a long time.

 

Nice! Makes me miss my FD