Why do people use a C20LET and not put a turbo on a 20XE?
I've been thinking again (don't laugh) and was wondering why people go to the trouble of taking an engine out normaly working perfectly well and put a C20-LET in when it is in essence a very similar engine. I assume there are differences in the cams, head (I know there is in the head), pistons etc... but what exactly are they and why is it better to swap rather than wiring and plumbing in a turbo on an XE?
Re: Why do people use a C20LET and not put a turbo on a 20XE?
Because it already has the sensors, ECU, peripherals, compression ratio and timing.
It certainly isn't an impossible task to turbocharge an XE properly, but it would cost a few grand. In today's market, you can pickup an LET engine for the same or less. 10 years ago this was prohibitively expensive though!
Yep, you can slap a turbo on to a 20XE cheaply. BUT, it's reliability and performance will be nowhere near that of the GM developed 20LET.
Secondly, even if you pay the money, and get a 20XE turbo'd properly, with mappable ignition/fueling etc, and moved to the Motronic 2.7 system, and used the correct sensors you will have
(a) spent more money than a 20LET will have cost you, especially as you can sell the XE for £500 still.
and (b) you still won't have a system that is proven to be reliable, such as the 20LET.