Jump to content
SAU Community

Recommended Posts

On a twin 2 inch system

R = 1 inch X pi (3.14) then square it = 9.88 cubic inches

times 2 pipes = 19.77 cubic inches

On a single 3 inch

R = 1.5 inches X pi = 4.7 squared = 22.22 cubic inches

So a single 3 inch pipe has more volumn then a twin 2 inch.

I rest my case...

Why are you talking about cubic inches?

Cubic = Volume

Volume is dependent on length, as V = Surface area x Length. So, if my 10 inch exhaust is 1 inch long, does that mean that my 1 inch exhaust that is 10 inches long has the same flow rate? No, because flow is more highly based on surface area rather than length (Unless you really want to get technical with gas velocity etc)

Hence, my use of surface area of a circle (exhaust size) as a comparo.

Also, fcruz3r, you will be more than happy with the Apexi muffler, STAGEN has one on his car.....AND I WANNA STEAL IT! :laugh:

Why are you talking about cubic inches?

Cubic = Volume

Volume is dependent on length, as V = Surface area x Length. So, if my 10 inch exhaust is 1 inch long, does that mean that my 1 inch exhaust that is 10 inches long has the same flow rate? No, because flow is more highly based on surface area rather than length (Unless you really want to get technical with gas velocity etc)

You could choose between 1x4" pipe or 16x1" pipes out the back as flow is inversly proportional. But this doesn't take into account the boundry layer separation that would create drag at the surface of each pipe which means the surface area has to be minimised. This means the 4" would outflow the 16x1". But just imagine the chicks you'd pull with 16x1" pipes. It'd be fully sick mate..

I don't think mr plod would be worried about that when he see's the pimpmobile, He'd be worried about db and clearance. Then again if he sees a 4" pipe out the back of a stocker, and a discreet pair of 2" out the back of a 600kW firebreather he's probably gonna pick on the 4" because he looks like jailbait.

One day I'll figure out how to separate the quote from the text. but today is not that day.

Why are you talking about cubic inches?

Cubic = Volume

Volume is dependent on length, as V = Surface area x Length. So, if my 10 inch exhaust is 1 inch long, does that mean that my 1 inch exhaust that is 10 inches long has the same flow rate? No, because flow is more highly based on surface area rather than length (Unless you really want to get technical with gas velocity etc)

Hence, my use of surface area of a circle (exhaust size) as a comparo.

Also, fcruz3r, you will be more than happy with the Apexi muffler, STAGEN has one on his car.....AND I WANNA STEAL IT! :whistling:

Thanks alexcim ...the apexi unit comes with a 4 inch inlet so I'd have to step up the current piping ...although there is a hks super dragger unit on ebay which looks oh so tempting :devil:

http://cgi.ebay.com.au/HKS-SuperDrager-Sta...1QQcmdZViewItem

too bad shipping will cost too much :woot:

You dont want a super dragger eh, went cruising with a mate in his old r33 with one and after 30mins I had to stop and get out, the drone was giving me a headache!

Got the whole end section replaced on saturday...must say that the guy at ian diffens osborne park did a fantastic job ...used 2 mandrel bends, a flange plate and a section of pipe...very pleased indeed.

the muffler does drone quite a fair bit at lower rpms (1.5-2k) but the beauty is at high revs...especially when it pulls past 3k rpm ...the exhaust sound almost completly fades away and all u can hear is the turbo chirping ...and got it mounted high so the body of the muffler is tucked away...very stealthy.

will be looking at a split dump..or a screamer for the next part of my project.

Don't even talk to me bout exhausts I got defected for mine the other week.

While yes I will agree it was loud (altough my kids never complain) the police officer was a dick!!

My exhaust is 3" from the cat bak with a cannon.

Won't even bother to quote the db reading before I got it fixed but it was loud..

Afterwards with the silencer in place and a shit load of steel wool in the guts it still only just passed. (and by saying this the guy felt sorry for and just let it pass)

But now I have the car engineered the Police cannot pick on me anymore.

Now I wish I had just left the car standard would have saved a shit load of money and all the hassles..

Edited by Mum's Taxi

huh?

area or a circle is pie x radius squared

radius of a 2 inch pipe is 1 inch

1x1x3.14= 3.14sq inces x2 pipes is 6.28 sqinchs

radius of 3"=1.5

1.5x1.5x3.14= 7.065 sqinches.

2 2"inches has more cross-sectional area than 1 3" pipe...

you all should go back to school... :thumbsup::)

or am I missing the point....

EDIT - looks like I can't add up either. Changed to correct value...

Edited by chrissso
Don't even talk to me bout exhausts I got defected for mine the other week.

While yes I will agree it was loud (altough my kids never complain) the police officer was a dick!!

My exhaust is 3" from the cat bak with a cannon.

Won't even bother to quote the db reading before I got it fixed but it was loud..

Afterwards with the silencer in place and a shit load of steel wool in the guts it still only just passed. (and by saying this the guy felt sorry for and just let it pass)

But now I have the car engineered the Police cannot pick on me anymore.

Now I wish I had just left the car standard would have saved a shit load of money and all the hassles..

oh sheet...i just got a speed ticket today + 1 demerit....last thing i want is to get my car defected :sleep:

might have my speedo checked....i swear i was doing 70...was picked up doin 78

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • What are we supposed to be seeing in the photo of the steering angle sensor? The outer housing doesn't turn, right? All the action is on the inside. The real test here is whether or not your car has had the steering put back together by a butcher. When the steering is centred (and we're not caring about the wheel too much here, we're talking about the front wheels, parallel, facing front) then you should have an absolutely even number of turns from centre to left lock and centre to right lock. If there is any difference at all then perhaps the thing has been put back together wrongly, either the steering wheel put on one spline (or more!) off, and the alignment bodged to straighteb the wheel, or the opposite where something silly was done underneath and the wheel put back on crooked to compensate. Nut there isn't actually much evidence that you have such a problem anyway. It is something you can easily measure and test for to find out though. My money is still on the HICAS CU not driving the PS solenoid with the proper PWM signal required to lighten the load at lower speed. If it were me, I would be putting either a multimeter or oscilloscope onto the solenoid terminals and taking it for a drive, looking for the voltage to change. The PWM signal is 0v, 12V, 0V, 12v with ...obviously...modulated pulse width. You should see that as an average voltage somewhere between 0V and 12V, and it should vary with speed. An handheld oscilloscope would be the better tool for this, because they are definitely good enough but there's no telling if any cheap shit multimeter that people have lying around are good enough. You can also directly interfere with the solenoid. If you wire up a little voltage divider with variable resistor on it, and hook the PS solenoid direct to 12V through that, you can manually adjust the voltage to the solenoid and you should be able to make it go ligheter and heavier. If you cannot, then the problem is either the solenoid itself dead, or your description of the steering being "tight" (which I have just been assuming you mean "heavy") could be that you have a mechanical problem in the steering and there is heaps of resistance to movement.
    • Little update  I have shimmed the solenoid on the rack today following Keep it Reets video on YouTube. However my steering is still tight. I have this showing on Nisscan, my steering angle sensor was the closest to 0 degrees (I could get it to 0 degrees by small little tweaks, but the angle was way off centre? I can't figure this out for the life of me. I get no faults through Nisscan. 
    • The BES920 is like the Toyota Camrys of coffee machines. E61 group head is cool, however the time requirements for home use makes it less desirable. The Toyota Camry coffee machine runs twin boilers and also PID temp control, some say it produces coffees as good as an E61 group head machine.
    • And yes with a full tank it will hit limiter free revving or driving 6B6CDF6E-4094-426D-A9CB-6C553475FE36.mp4
    • One way of putting the fuel surge idea to rest, is that even when in neutral/clutch in or free revving it still has the same issue, it can’t even get to limiter (7800) so to me that says it can’t be g force, I’m not trying to argue I just want to find the f&$king issue 😡
×
×
  • Create New...