Proof of larger DP/ Fluid Dynamics

[rst95eclipse]

Yes yes yes. I agree with all of you, but this isn't a "Why not go 4" all the way back" question. I drew up a scenerio. I would like answers, not suggestions. I believe the post that started this thread indicated that.

Sport Compact Car's September 2004 issue has WOTM's Supra featured. It states in the article that he had a 3" exhaust and was running 10.2 in the quarter. He bolted a 4" downpipe and midpipe and immediately ran 9.9. Has anyone else done this and seen this result?

[Shane@DBPerformance]

I have seen people pick up 3 tenth in the quarter by changing nothing.

WOTM used to fight about something on Supraforums a lot about downpipe size, but I think Sound Performance proved him wrong a few times.

[1ViciousGSX]

Larger is usually better up to a point, but remember that your turbo is your biggest restriction in your exhaust system. :cool:

[rst95eclipse]

Larger is usually better up to a point, but remember that your turbo is your biggest restriction in your exhaust system. :cool:
Yes, but technically you want it to be the restriction.

[Goat Blower]

A turbo is a restriction to the engine itself, but since the turbo makes positive pressure, it's technically not a restriction. The less restriction after the turbo is best.

You're clearly asking this question in the wrong place, there's only about 5 DSM'rs in the country that'd have a solid answer for this. You're asking the 16G crowd here, thereby wasting yours and our time.

[Jakey]

but since the turbo makes positive pressure, it's technically not a restriction.

Huh? The entire exhaust "track" of an automobile, whether it is turbocharged or not, is one big pressure differential. It is that pressure differential which causes the exhaust to flow because of your tailpipe being at atmospheric pressure and the exhaust exiting through your exhaust valves is at a much higher pressure. Since gases flow from high pressure to lower pressure, that's why automobile exhaust flows the way it does.

I wish I had a better handle on my fluid dynamics because I do not believe the crude calculations associated with the original question in this thread to be very complex.

[rst95eclipse]

A turbo is a restriction to the engine itself, but since the turbo makes positive pressure, it's technically not a restriction. The less restriction after the turbo is best.

You're clearly asking this question in the wrong place, there's only about 5 DSM'rs in the country that'd have a solid answer for this. You're asking the 16G crowd here, thereby wasting yours and our time.
I think you're wrong on both ends here. From what I can see, there are about a half of a dozen (at least) running GT35+ series or SCM61 in this forum.

I wouldn't know why a turbo wouldn't be a restriction.
1. Generally the pressure in the exhaust side is about double of what is in the compressed side.
2. The combustion chamber divides the intake and exhaust tracts. More pressure is caused by the explosion (expansion).
3. The turbines are spinning, but they're creating some backpressure. Which is why after the turbo, the best exhaust system is no exhaust system.

[Kracka]

By "16G crowd" I don't think Steve was referring to the turbos people are running. Maybe I'm the only one who laughed after reading that ;)

[niterydr]

By "16G crowd" I don't think Steve was referring to the turbos people are running. Maybe I'm the only one who laughed after reading that ;)
No, I chuckled as well.

[TalonFiero]

No, I chuckled as well.

I cried. :(