True ... raising the WHp will raise the torque at a given RPM:

Horsepower = (Torque*RPM) / 5252

But gearing has to be factored in. The HR/VHR may have a lower peak torque, but it will pull over a wider RPM range.

Trust me, 6-7 PSI will work fine for a daily driven HR/VHR. 10-11 PSI is on the high side for this motor ... you can always put in a boost controller for the rare occasions you run up against a "tough kill". ;)

Jeremy,
I would be willing to trade my invidia gemini exhaust, as I wouldn't mind super loud and annoying on mine. especially since its too low to clear the speed bumps at work now, and is truly a weekend track and mountain run only car now.

Color me a bit uneducated, but what is the diameter of the Invidia? What model do you have? And do you think it will drone less than the GReddy? I'm interested, but I need to make sure I quite this hooker down without restricting the flow of exhaust.

Guys, terrific job with this car... agree with an earlier comment about it being the best looking street oriented 370z on the board! I look forward to some driving videos! :tup:

60 mm with 101mm rolled tips. muffler and tips are satin black, but I can always recoat to your gray metallic.

Invidia USA.

it should quiet and drone less, it definitely took the rasp away from my test pipes. Since Teresa won't drive the car anymore with the wing, I may as well also make it where she won't ride in it either!

Thanks, Travis! BTW, your name changed color. Gotta make it gold again! AK is counting on you! *lol*


Let me do a bit of research on how the change from 70mm to 60mm piping is going to affect the car. I think I should be ok, but certainly want to make sure. Sam is sending the resonators back for the rear cans and I may want to try popping those in, as well. Either way, I'm going to restrict the exhaust flow of the car.

LOL'ing at your comment re: Teresa. BTW, i'm telling her what you said! :tup:

Hey she has her Beemer... He gets the z lol

Soooo much part pron in this thread. So much hardware, looks nice. Perfect stance on the car and the EVC install looks very clean as well. + 1 on possibly the best street Z on the boards to date.

Clean clean clean

i love the location of that EVC, amazing car dude.

agree! somehow I let things lapse, but AK should have my money by now... if not, will get it soon

let's make a deal, I reinstate my OG and you change your avatar! :tup: I like the one of your 370z coming off the truck!

Drone in the exhaust is due to the engine driving the exhaust system at its resonant frequency. You can't get rid of it, any length of pipe has a natural frequency, but you can change the frequency (RPM) it happens at. Stock exhaust systems are tuned to put the resonant frequencies outside the normal RPM range the engine is run in. Sometimes they add resonators for this purpose. To raise the resonant frequency of a system, shorten its length. To do this, you can try tail pipes that exit by the wheel (like GN's have), or you can try a muffler with a shorter internal flow path. If you have a true dual system, you can change the natural frequency of the system dramatically by adding a balance tube. If you can't shorten the system, then you can add slightly less than one wavelength of pipe. This will also raise the resonant frequency of the system. The wavelength in a single converter system (not true dual) is a little less than three feet at 3000 RPM. Shortening the system by a foot or so will move a resonance at 2000 RPM to about 3000 RPM.


To move a resonance, calculate the wavelength at the RPM that gives the resonance you want to move. Then calculate the wavelength at the RPM you would rather it be at. The difference is the length of pipe you need to add or delete. Add to lower the RPM, delete to raise it. If you want to raise it but you can't cut any pipe out, then add one wavelength of pipe minus the amount you calculated. This will have the same affect. If you add or subtract a multiple of a wavelength exactly, you will not change the resonant RPM.




Wavelength = 1100 X 60 X 1/RPM X 1/4 X 1/2

or

Wavelength = 8250 / RPM

Wavelength = standing wavelength
1100 = speed of sound in air in feet per second
60 = convert RPM to Revs per second
RPM = RPM
1/4 = four cylender firings per revolution (make this 1/2 for "true dual")
1/2 = standing wavelength is half the wavelength of a "normal" wave

I love where GTM put your HKS EVC boost controller, looks like it was made to fit there. Is the fit really as good as it looks?
http://i313.photobucket.com/albums/l...D/P1110372.jpg

Just wondering why you did not go with external wastegates?

Deal. I just needed to get a good pic of my Z before changing the avatar. Now there are so many to choose from!



Thanks for all of the information on resonance. I don't think I can delete any of the length of this GReddy piping, so I will try the resonators they place in the cans at the end and see if that helps. If not, then I think I will just try to stick two bananas in the tailpipes. :)

The EVC's fit is just as good as it looks in those photos. The only caveat is that the angle is a bit harsh for the driver and it takes some maneuvering to read. That and at night, the light from it is in the passenger's eyes. *haha* Who really cares about that, though?

I didn't want open dumps, so no externals. I didn't want to recirc them, either. For the power level that I wanted, internals were perfectly fine. Any possible boost creep/spikes is going to be mediated by the EVC. But, I haven't seen any yet. Even with the more free-flowing exhaust.

Love the picture change! The unwanted sound you are talking about, is it coming from the mid pipe?