Any pricing?
I wonder why Top Secret's pipe is a ~45 degree Y whereas these are more like an ~80 degree shape.
I suppose we still shouldn't buy since Y-pipes are making the Z run reeeal lean.

 

who cares? these won't make any considerable power over stock. stock is already a good enough design. unless of course what you're looking for is to waste money. the whole stock exhaust system after the headers is already great, and about the best stock exhaust system out there. fully mandrel bent ss, you can't do much better than that.

 

Like Victor says, there is room for improvement over stock, I have seen it personally how a y-pipe and staright pipe will increas HP and once the ECU reprogram is out then it will be even better for those with aftermarket mods already on.

 

ummm....im sure there will some difference considering the stock pipes are pretty small and restricted.

 

Daytona: can you say more about Y pipes making the 350 run lean? I've not seen that mentioned here before. Thanks

A friend is making several Y-pipes and we plan to dyno next week. I'll keep the one that shows the most improvement.

 

Im not sure what your basing this on. Granted there have been only mixed results with the few replacments muffler sections available, there have not been enough commercialy available full cat backs around to determine the real efficency of the stock cat back. Keep in mind that the Z is still relativly brand new and there is ALWAYS room for improvment over stock with proper design.

 

Totally off topic, but how long has that Back to the Future quote been in your sig? Can't believe I've missed it if it's been there. Love that movie

 

heh, about a week Ive been keeping them fresh weekly lately, think I'll start a contest to see who can identify the most obscure quotes

 

a) i cant wait until mine's releases a total car project. so cool.

b) there is always room for improvement, but remember than with an NA motor you dont want a 4inch pipe like a turbo. NA motors benefit from a little back pressure.

c)i want to know what daytona is talking about the y pipe making the z run lean, too. anyone care to drop some knowledge?

 

The idea I have as to why the Y-pipe would make the car run lean is if it eliminates the cats so the O2 sensors are not getting the correct info. A similar thing happened on my 240SX when I removed the close-coupled cat except that the car ran richer than stock. If this is the case, O2 simulators should cure this problem.

 

the stock pipes are smaller but they are by no means a restriction. you can't just look at something and say it's small therefore it's a restriction. the exhaust doesn't flow enough for it to be restricted. increasing the cross sectional area will not give you additional power. it's like adding lanes to a freeway that barely has any cars on it, it's not going to make traffic faster. if you want power get aftermarket headers, that is the biggest and pretty much only restriction on the exhaust or intake side. i suspect upcoming ecu's won't be able to do much to lean out the fuel mixture because of how the stock intake manifold is designed. the im design leaves the forward cylinders suspectible to leaning out.

 

The Y-pipes posted by VQ both have the catconvert still in place.
They even keep the flex-pipes. So I guess running lean would not result from either of those mods.

 

I could be wrong but I think they're resonators, not cats in the pics above.

 

What is "im"?

 

My guess would be intake mainfold and the theory could be correct in extreme applications IMO.

 

I think you're right apsilon. The cat is upstream from the Y pipe.