An interesting Q&A

Taken off the SG Evo Club Forum:

cavallino wrote:

guys, what's the difference between:
1. slapping a HUGE turbo onto a stock engine
2. stroking up the engine to 2.4L and using a stock turbo.

Response by a senior member with a very good understanding of tuning principles:

Area under the curve.

You NEVER look at just peak figures. You want to know what's the percentage of peak torque available throughout the rev range.

A small turbo with large engine will give you peak boost from a lower rev and sustain that through a pretty large rev range. Think GTR 2008 or 997 Turbo engine for instance. Peak torque from <2000rpm style="font-weight: bold;">heating and reliability

both have shares of issue in terms of reliability. Basically once you modify, be prepared to reduce yr service interval periods

Depending on who builds yr stroked up engine, you may have reliability issues.

Big turbos will need a lot more upgrades to cooling as well.


torque curve (one is better at low end and the other at higher end?)
See earlier paragraph


fuel consumption
As usual it depends on how you drive. If you need to hit the high torque range all the time, the stroked up engine is probably better since you get it at lower revs. If you are a more disciplined driver, and can drive the car offboost, the larger turbo is better for FC.

As usual, I find it silly to discuss FC when you are concerned with power.


pick up, response, lag
Torque under the curve. Bigger engine better


noise
Depends on whether you put stuff like external wastegates, BOVs etc