[monsterdog]

I'm trying to design a new muffler for my n/a 78 280z. Here is my thoughts the muffler will regulate back pressure. I want more back pressure at lower RPM and low to no back pressure at higher RPM.

I've seem to have lost some zip from accelation and gain a whole bunch of power from midrange to higher RPM. This has happen since I install the Flow Master muffler, cold air induction system and big throttle body set up. I replace the Flow Master with a Dynomax turbo muffler with much more back pressure and wow accelation from the start was much improved. Wheels chirp in the first two gears. However, mid to upper range Power has dropped off .

1.Give me your thoughts on back pressure..

2.My second question has been answered. There is a new muffler comming to market to address this issue for the ricer crowd. I'm going to find out who make this product and what is the design. Maybe we can adopt the application to or z cars.


Peace

Monsterdog...

 

[EagerCrow]

This has been done on Motorcycles for some time. You could most likely get some info from the crotch rocket crowd out there. My friend has a muffler that does this on his Yahama R1, I believe that is what the bike is called, it's got a blue paing scheme and fast as ****.


Josh

 

[BleachZee]

the newer Nissan maxima has had this style of muffler for a couple years. I think since 1999. It has a single input and chambered exhaust. At a certain pressure a second hole opens allowing a straight through design with two outputs.

 

[Andrei]

If you want to really save money, use the muffler that provides the most backpressure to get the best acceleration, and then install a Y pipe before the cat, that you can flip from muffler to open air. that will give you the best top end, but might give you problems with smog regulations.

 

[avernet]

I was going to say the same thing about the Maxima muffler. I wonder if it would work well on the z's???

 

[monsterdog]

Re: Thanks

You all have been helpful. I'll keep you all in touch..

 

[beaterZ]

Another idea on this

You could always have a 3-into-2 system that goes all the way back (with an X-pipe so all the exaust could go out of one pipe if the other one was shut off), and then have a flap at the very end of one of the pipes that is opened and closed via a small silinoid at a ceratin RPM that is read off of the tach.

That way you would have to worry about any smog regulations as one of the other people mentioned in a previous post.

Seems like a pretty simple solution to me

 

[Unknown User]

Re: Another idea on this

there are rpm activated switches in jeg's. also the muffler bypass valve, which comes with a choke style wire to activate it. i'd imagine if you put an electric silinoid on the bypass, and hooked the rpm switch through a relay to it, it would work. pushing and pulling that cable every time you shift would really get old, and one more thing to worry about when racing. just lube it often to make sure the plate in it don't hang up enough to block the silinoid,,,,,,,,,