Nissan 370Z Forum - Fast Intentions exhaust is here!

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- - Fast Intentions exhaust is here! (http://www.the370z.com/intake-exhaust/6215-fast-intentions-exhaust-here.html)

Quote:

Originally Posted by XwChriswX (Post 1134552)

First point - The hiss comes from having an X-Pipe. Has nothing to do with Stock cats or HFCs or test pipes. If I recall correctly it is from the equalization of backpressure between the two sides of the system... Tony will have to come in and 100% answer that one. But the only way to defeat the hiss is to have either a complete dual system or have an H pipe as with the Nismo exhaust.

Second Point - The overheating issue... When you installed your CBE/HFCs, did YOU do it or did you take it to a shop and have them do it? In either instance, did you get it tuned afterwards? If no tune did you at least pull off the negative battery terminal for a few minutes to reset your ECU? Adding these breathing mods allows your engine to flow more air = more power. However comma if you haven't reset your ECU to adapt to this, it might still be running the same cooling maps as it would for stock. Which now that you're getting more power your block is heating up faster and the ECU isn't compensating for this. If you haven't done the battery reset, I would suggest to try that, remove the NEGATIVE terminal for about 5 minutes. Then return it and crank. Let it sit and idle for about 10-15 minutes. Then take it around the block a few times without getting on it. And let your ECU learn how your engine reacts with the new mods. Maybe this will help it adapt better and keeps your temps back down where they were. Or it could just be due to the weather getting warmer/more humid...

:tup:

Hey thanks for you information. I did bring it to a shop to have it installed and I did not get a tune. I was under the impression that with just bolt on applications, you wouldnt have to worry about the ECU and that it would adjust itself with some miles. If i dont see a change in the temp after driving it a bit more, I will do as you have suggested and remove the negative battery terminal as instructed. Thanks again for you advice...

Quote:

Originally Posted by XwChriswX (Post 1134552)

First point - The hiss comes from having an X-Pipe. Has nothing to do with Stock cats or HFCs or test pipes.

Hmmm I know of someone that has HFCs with a Y-Pipe and the hiss there.

Quote:

Originally Posted by b1adesofcha0s (Post 1134585)

Thanks :tup:

:tiphat:

Quote:

Originally Posted by Pelican170 (Post 1134609)

A tune isn't completely necessary unless you do full bolt-ons, but it's still good practice to do the battery reset anytime you change any performance mod. The ECU would eventually adapt to the new things over a given amount of time, but instead of the adaptation we want it to have, it would think something is wrong and cut back power. This way you're starting fresh and it takes what it's reading from the engine as 'normal'. :tup:

Quote:

Originally Posted by Ron (Post 1134626)

Hmmm I know of someone that has HFCs with a Y-Pipe and the hiss there.

Do they have the stock exhaust still?

Aftermarket Y-Pipe and HFCs, the rest is stock.

Quote:

Originally Posted by Ron (Post 1134669)

Aftermarket Y-Pipe and HFCs, the rest is stock.

After the Y-Pipe the stock exhaust splits back into two pipes then goes into the muffler, which I believe is perforated to allow the banks to balance out again.

Yep, but if he has hiss with this setup, then hiss is not caused solely by an X-Pipe. I think its the HFCs.

Quote:

Originally Posted by Ron (Post 1134710)

Yep, but if he has hiss with this setup, then hiss is not caused solely by an X-Pipe. I think its the HFCs.

You do realize it's still technically an X even if you install a Y-pipe...??

=>-<=

Is there hiss on a completely stock exhaust on a non-nismo Z?

Quote:

Originally Posted by Ron (Post 1134858)

Is there hiss on a completely stock exhaust on a non-nismo Z?

Believe so, but it's muffled enough you can't tell. I could hear it when decelerating from high rpms, but now it's much more pronounced with the straight through exhaust.

So I guess we can agree that hiss is caused by the extended X-Pipe design on non-Nismo Zs but incremented by the addition of HFCs since they are less restrictive. Less restricion = less muffled sound = more hiss. Same goes for TPs. Yes? No?

Quote:

Originally Posted by Ron (Post 1134897)

I would agree to this. The sound is inherent from an X design, and with the increased flow from HFCs or TPs or LTHs' the hiss is more pronounced... Here check this out:

http://i584.photobucket.com/albums/s...3/image002.gif

See how both pipes come together and even if you get an aftermarket Y pipe, you're still maintaining the X profile.

http://i584.photobucket.com/albums/s...3/image001.gif

Here is the Nismo exhaust, notice the H crossing instead of a Y/X. Very different in terms of how it affects/improves the flow. This is why it's less noticable on a Nismo.

**Pics courtesy of my350z.com

I see what you are saying, but I think that even though the overall shape of the stock exhaust looks like an X, I would not call it an X-Pipe design and don't think it acts the same way.

True X-Pipes are basically 2 tubes with a small opening in the center connecting each other, right after this, they split into separate pipes.

http://www.albertpenello.com/vette/xpipe2.jpg

http://i371.photobucket.com/albums/o...s/IMG_5036.jpg

On the stock design, gases come together on a single relatively long pipe and then it splits again. I think this would have an effect in sound and performance.

http://www.dragtimes.com/images-clas...0491418379.jpg

I guess what I wanna get at is that the hiss is caused by something else. Stock setup uses Y pipe and hiss is there... FI setup uses X pipe and hiss is there. Maybe its something with the engine itself, exhaust valves, gremlins. Lol I don't know.

Well, Chris's explanation about air pressure equalization between banks makes as much sense as anything else I've heard. If that's what causes the hiss, the hiss is probably present on any exhaust setup with a decent connection between the two sides, it's just a question whether and how well you can hear it under what conditions.

Quote:

Originally Posted by wstar (Post 1135096)

This is probably why the base stock exhaust is setup the way it is. To mitigate as much of this hiss as possible.

anyone have FI exhaust with CNT Racing HFC ??