4G63 Big Turbo Selection – 600BHP
Compressed by jpeg-recompress
This 4G63 big turbo selection guide follows the usual template. Let’s get into it.
VE
Step 1, what’s the VE of the motor at the RPMs we’re interested in. Dyno graph is here for stock turbo car, with a tune, we’ll use this to get the data for the VE calculator.
| RPM | Boost | BHP | VE |
| 3000 | 12.5 | 120 | 0.76 |
| 5500 | 24 | 330 | 0.78 |
| 7500 | 21 | 310 | 0.59 |
CFM and Pressure Ratio
Bolting those numbers into the turbo calculator to get the flow numbers
| RPM | VE | Boost Target | CFM | PR | lbs/min | Power (est) |
| 3000 | 0.76 | 5 | 107 | 1.34 | 8.3 | 88 |
| 5500 | 0.78 | 30 | 460 | 3 | 35 | 370 |
| 7500 | 0.59 (0.78) | 30 | 628 | 3 | 48 | 504 |
| 7500 | 0.85 | 35 | 761 | 3.4 | 59 | 611 |
Turbo Compressor Maps
Good, but I think we can do better
4G63 Big Turbo Calculation – Conclusion
The older turbos that can do the business up top, but lose out down low to the G-Series turbos. And the old turbos that can do the bottom don’t have the head room of the newer gen turbos.
Dynograph
Here is a dynograph of a 2.2 litre, EVO 8, with this Gen 1 G30-770 turbo. It’s revving to 8500RPM. At the top end I think the Gen 1 G30-770 is maxxed out and probably over speeding. For this 2.2 motor, the Gen 2 G30-775 probably a better fit. Gen 1 turbo probably a bit small for this motor.
Be that as it may, I think it’s a good example showing how the calculations in this article compare to reality.
