first350

iTrader: (24)

So I've been kicking around a lot of ideas on some active intake and/or exhuast systems...what I haven't found is:

1) What is the Intake manifold pressure
-vs. RPM @ WOT
-vs. RPM @ 3/4 throttle
-vs. RPM @ 1/2 throttle
-at idle
2) What is the exhuast pressure (near y-pipe or mid-pipe)
-vs. RPM @ WOT
-vs. RPM @ 3/4 throttle
-vs. RPM @ 1/2 throttle
-at idle

**I'd love info for the 350z, but other NA applications would also help.


any help or a 'point in the right direction' would be greatly appreciated

thanks,
Peter

Wired 24/7

iTrader: (2)

Wow... no idea whatsoever.

Intake manifold pressure vs. RPM you could do with an engine management system and a pressure sensor. But usually just F/I guys care about manifold pressure. N/A guys can get by with MAF signal and don't care about MAP.

Exhaust pressure... GOOD LUCK, I'm not aware of anyone ever measuring it.

It's not impossible, you could just drill into the y-pipe and get a capacitance manometer from MKS, along with a digital readout. But then you wouldn't have much datalogging capability.

first350

iTrader: (24)

I thought about that...I should have tried this stuff before I switched jobs - my last company had a portable temp/pressure data logger that I could have used.

*I know that the new corvette exhaust has an some butterfly valves that open up to allow for more flow (and power) based on throttle position...I'm not sure exaclty how they're doing this, but was wondering if they were using something like a BOV (blow off valve) to magnify the difference between the intake manifold pressure and exhaust pressure to open the valves..

my general understanding is that @ WOT, NA intake manifold pressures drop and exhaust pressure increase...I just don't know by how much and how they relate more precisley to RPM.


I've been tyring to come up with a design that will keep my exhaust really quite when I'm not on the throttle (around my neighbors), but will open up when I want some fun.

jdemos

iTrader: (1)

00-03 Maximas had a dual valve muffler. One opened at partial throttle and both opened under full throttle giving more flow. Im sure they werent linked to the throttle body, merely the exhaust pressure. Dont know if that helps but thats my $.02

-Chris

Wired 24/7

iTrader: (2)

Just would like to point out that while your idea is interesting and I don't it's been done before on a Z, you will probably spend far more time and money pursuing this project than if you just go with a nice exhaust with proven results.

There is not that much N/A power to be had with JUST exhaust mods on the 350Z. To make serious N/A power you need headers, cams, and tuning at least.