2.5 or 3" exhaust piping
2.5 or 3" exhaust piping
whats the best pipe diameter for your TBE if you don't plan on changing the stock turbo?
Last edited by veilside prius; Dec 27, 2007 at 07:52 PM.
Alright, I hit my goal of 150 mph trap speeds with my RS. I was happy......for about a minute
Now I am on my winter quest to gain even more horsepower than I had.
Last week we re-installed my SSR wheels and Toyo tires, the car is much nicer on the dyno with these tires.
Then last Friday I brought the car in and built a complete 3.5" V-band exhaust for it. I wanted the lightest muffler I could find so I ordered a 17" long Burns Stainless muffler, weighed about 4.5 pounds. When it was all finished the entire 3.5" mandrel bent stainless exhaust system came in at 38 pounds from the turbo back. This is 8 pounds heavier than our 3" system I took off the car.
I loaded the car on the dyno, made no changes to the tune or boost and made two back to back pulls.
We then took the car off the dyno, put the 3" exhaust back on the car and did two more back to back pulls.
Below are the two dyno sheets. The #1 run on each one is the 3.5" exhaust, #2 is of course the 3" exhaust.
First dyno sheet is:
3.5" made 661 whp and 620 torque
3" made 669 whp and 617 torque
2nd dyno sheet is:
3.5" made 669 whp and 603 torque
3" made 659 whp and 599 torque
The testing, as far as I am concerned was a complete wash and I can't call either system a winner in the testing. As far as what I am going to do, I am leaving our 3" system on the car, it's quieter, lighter and I see no power gains averaging the two charts.
I did go back and measure the outlet size of the GT35r turbine housing, it is only 2.5". I know for certain that as the exhaust wheel/housing gets larger going up in the exhaust size is going to help but for a GT35r or smaller and from what looks like 700 whp and under there just isn't any change in power to say it does or does not help.
BTW, for the haters, it would be very easy to change the testing results (as would any other test I have ever done) to show that EVERYONE needed to upgrade their current 3" exhaust to a 3.5". I have (15) 3.5" exhausts on our shelf right now. That's not how I operate, never has been, never will be. The test is what it is and I guess it is going to take a few years of installing GT42r's on street cars to use up this tubing I have................
Now I am on my winter quest to gain even more horsepower than I had.Last week we re-installed my SSR wheels and Toyo tires, the car is much nicer on the dyno with these tires.
Then last Friday I brought the car in and built a complete 3.5" V-band exhaust for it. I wanted the lightest muffler I could find so I ordered a 17" long Burns Stainless muffler, weighed about 4.5 pounds. When it was all finished the entire 3.5" mandrel bent stainless exhaust system came in at 38 pounds from the turbo back. This is 8 pounds heavier than our 3" system I took off the car.
I loaded the car on the dyno, made no changes to the tune or boost and made two back to back pulls.
We then took the car off the dyno, put the 3" exhaust back on the car and did two more back to back pulls.
Below are the two dyno sheets. The #1 run on each one is the 3.5" exhaust, #2 is of course the 3" exhaust.
First dyno sheet is:
3.5" made 661 whp and 620 torque
3" made 669 whp and 617 torque
2nd dyno sheet is:
3.5" made 669 whp and 603 torque
3" made 659 whp and 599 torque
The testing, as far as I am concerned was a complete wash and I can't call either system a winner in the testing. As far as what I am going to do, I am leaving our 3" system on the car, it's quieter, lighter and I see no power gains averaging the two charts.
I did go back and measure the outlet size of the GT35r turbine housing, it is only 2.5". I know for certain that as the exhaust wheel/housing gets larger going up in the exhaust size is going to help but for a GT35r or smaller and from what looks like 700 whp and under there just isn't any change in power to say it does or does not help.
BTW, for the haters, it would be very easy to change the testing results (as would any other test I have ever done) to show that EVERYONE needed to upgrade their current 3" exhaust to a 3.5". I have (15) 3.5" exhausts on our shelf right now. That's not how I operate, never has been, never will be. The test is what it is and I guess it is going to take a few years of installing GT42r's on street cars to use up this tubing I have................
Last edited by RoadSpike; Dec 27, 2007 at 11:08 PM.
