Screamer pipe

[aybee]

i have a screamer pipe on an external gate on my car. yes it is very loud, and yeah i guess it sounds like a jet. i hope its not 10k fine cause that would be very bad. if cops are around its not a problem because external gates come on big turbos so they open up late. mine opens at around 4500 revs so its quite easy to drive without it openning if you want. and yes you can pipe them up, they pretty much go straight back into the exhaust just before the cat.

[Sydneykid]

Hi guys, on a turbo car, the rapid rotation of the turbine "cuts" up the noise waves. So if you run an open exhaust (no mufflers) the noise from the turbine it is not as loud as that from wastegate. There is no cutting, so the noise is substantially louder (more than 10 db) from the wastegate.

I have never seen any significant horsepower loss from plumbing the wastegate back into the exhaust, if it is done properly.

So it's just noise for noise sake, no performance gain.

[aybee]

Originally posted by Sydneykid

I have never seen any significant horsepower loss from plumbing the wastegate back into the exhaust, if it is done properly.

define "properly"

i am planning on piping up the gate when my car is rego'd. the screamer pipe has a flange on it and my front pipe has has a flange that has been covered just in front of the cat. i assumed that all it needed was a pipe going from one to the other.

[Guest nismo_trip]

So are external wastegates which dump to the atmosphere illegal ?

[akeenan]

obviously!

[aybee]

yeah its illegal, but then agian so is non plumbed BOVs and cooler if have pod, and too low cars, and too loud cars, and big tubos, recaros, metal centred steering wheels, etc. youd be surprised just how many illegal cars are driving around every day.

[Sydneykid]

Hi aybee, "properly" means;

**Joins the main exhaust more than 300 mm from the turbine

**Has allowance for differential expansion (slip joint or flex pipe). Otherwise it will crack due to the different expansion rates, the main pipe expands as soon as hot exhaust, via the turbine, hits. The wastegate pipe doesn't get hot until the wastegate opens. Result = constantly cracking joints. You can help this by wrapping both pipes together with exhaust wrap.

**Has good flowing joints, not a right angle, as I have seen more often than I would have thought possible.

**Is of the appropriate inside diameter.

**The pipe from the joint onwards is of sufficient inside diameter.

Basically standard good sense that any decent exhaust shop should know.

Hope that helps

[aybee]

Thats all cool, except that i assumed you could just use mild steel but i hadnt thought about the heat thing. what are my options?

[aybee]

Cheers sydneykid

[DREMEN]

aybee, thos illegal things that you listed are illegal according to the RTA but the screamer pipe is more to do with the environmental laws and therefore the fines are *HUGE* compared to standard defect fines.