Thinking outside the block
 

OK a cheap play on words i know.
I was reading a few threads here about the use of low pressure turbo and gearing to put the engine is a better "sweet spot". BSFC plateau. I have not been able to find one for my engine (KA24DE) but still searching

I was out cutting grass last night - neighbor came home - he drives a Sentra.
1.8L 4cyl engine. and i start to think... Could i downsize my 2.4L engine for a 1.8L engine - add a LP Turbo to give me the same basic torque value?

So i seached Wikipedia for the 1.8L engine info.
"The 1.8 L (1769 cc) QG18DE was designed for Nissan by Aichi Machine Industry, Japan. Bore is 80 mm (3.1 in) and stroke is 88 mm (3.5 in). The engine is tuned to achieve most of its torque at low revs at the expense of raw power at high revs making the engine very responsive in day to day driving. It has a cast iron engine block and aluminum DOHC cylinder head. It uses MPI fuel injection, and features forged steel connecting rods, a one-piece cast camshaft, and a cast aluminum intake manifold. It also features NVTC (Nissan's Variable valve Timing Control technology)."

WHat caught my Eye was the phrase "tuned to achieve most of its torque at low revs".

KA24DE
Power: 157 hp (112 kW) @ 5600 rpm
Torque: 160 ft·lbf (217 N·m) @ 4400 rpm

QG18DE
Power - 126 hp (94 kW) @ 6000 rpm
Torque - 129 lbf.ft (174 nm) @ 2400 rpm

Besides the Multiple issues with making a smaller engine fit and the overall cost of this - Would there be a siginifit FE impact here?

I would have to think going from 2.4L to 1.8L if i can "match torque" would have a huge impact. but how much?

Besides - at the end of the day - doing all this effort - why not just "Swap Cars" instead of "Swap Engines"

I will think of it as a mental exersize for the moment.

(Besides i can probably find a Ricer who wants to put the 2.4L in his sentra and give me is 1.8L engine.)

I would do it if it's an easy swap. The don't appear to be the same series motor, so I doubt the mounting points will line up, and there might be other issues, but if you can find a cheap motor why not? Or better yet, a cheap sentra, :p

IMO you wouldn't even need the turbo. Your only loosing 20% of your maximum horsepower. When is the last time you needed that extra 31 horsepower?

Swapping cars would be much easier.