Out with the old, in with the GT4202R
08-11-2008, 04:02 PM
#23
The Dmax guys love that turbo for making good power, you have the same cubes as us now and its supposedly slightly laggy but has great top end. If that rubo can put a big heavy diesel into the high 10s it should have no problem getting your lightweight truck into the 10s. 
08-11-2008, 11:25 PM
#24
Question...if your using the same turbo as the Diesel's and have the same cubes as they do, won't you be spinning that turbo out of it's efficiency range? You'll most likely be spinning your truck way faster than a diesel...I would hope. Then again I guess it's more about exhaust flow and volume of the exhaust that matters I would assume. And HP is HP any way you cut it so would the volume of exhaust be the same for a gasser putting out 1000 crank hp the same as a diesel pushing out 1000 crank hp?
08-11-2008, 11:36 PM
#26
Here's the compressor map for this turbo. It's the 102mm wheel.
Here's an airflow table for a 408ci LS1...mine should be pretty close to this.
At 15 psi (2.02 pressure ratio) and 5700 RPM (which is where I plan to shift) it looks like my engine should consume roughly 76lbs/min of air. At 76lbs/min and 2.02 PR I will be close to the last efficiency line of the turbo.
I'm not sure what RPM the diesels usually run to, but I'm guessing it's somewhere around 4000. If you looks at 4000 RPM, you can take a linear extension of the chart out to 30 psi, which should give you about 82 lbs/min at 30 psi, which is about 3.04 pressure ratio. Looks like that's right in the meaty part of the table for the diesel guys.
I may try short shifting the engine and running more boost....should put the turbo more into it's efficiency range.
Here's an airflow table for a 408ci LS1...mine should be pretty close to this.
At 15 psi (2.02 pressure ratio) and 5700 RPM (which is where I plan to shift) it looks like my engine should consume roughly 76lbs/min of air. At 76lbs/min and 2.02 PR I will be close to the last efficiency line of the turbo.
I'm not sure what RPM the diesels usually run to, but I'm guessing it's somewhere around 4000. If you looks at 4000 RPM, you can take a linear extension of the chart out to 30 psi, which should give you about 82 lbs/min at 30 psi, which is about 3.04 pressure ratio. Looks like that's right in the meaty part of the table for the diesel guys.
I may try short shifting the engine and running more boost....should put the turbo more into it's efficiency range.
Last edited by thunder550; 08-12-2008 at 12:13 AM.
