Why only 2.4 quarts of oil?

[theaveng]

Every 4 cylinder car I've owned used 4-5 quarts. Therefore I would expect a 3 cylinder car to use 3 to 3.7 quarts (three-quarter as much lubrication). Instead the insight uses much less than that. I'm surprised the oil does not wearout early.

How do engineers determine how much oil to supply an engine?

[Need4Speed]

Most older American v8 cars used 5 quarts, about a quart per liter displacement......the insight should use about a quart doing the math that way.....based upon horsepower.....maybe a quart also.....

[spets]

Lubrication would be the same whether you had a 10 qt capacity or a 2 qt capacity.

Smaller engine with less horsepower, lower friction, and less wear and tear with the IMA assist. The only thing more oil in the sump gives you is a greater heatsink and more oil additive capacity before you have to change the oil.

With the lower amount of wear, I'm sure Honda decided that 2.6 qts would provide enough room for 7,500 mile oil changes.

[Cobb]

Good question, good answers. I only know high rpms can pump the oil to the top of the engine faster than it can drain back to the pan as to why they increase the capacity or use a remote sump for race engines. Also the G forces can move the oil to one side causing the system to get air in it. Some have a sump with a moving pickup or dual pick ups for the pump.

Too much oil and the rods will sling it all over the place, cause some leakage and loose some hp and mpg.

[Eli]

My guess is that the things Spets mention allowed Honda to get 7,500 miles out of only 2.6 quarts, and thus go green in a way most of us have never considered: A smaller oil sump. Less oil consumption!

If the Insight had a 4 quart sump I bet you could get 20k out of a change easily under good conditions.

[samwichse]

On the other hand, my '66 Beetle also only took about 2.5 qts, but I had to change it every 1500 miles!

Hot-running aircooled engine, no filter (except the sump screen), and a splash-lubrication system.

Of course, I adjusted the valves every 6k miles too, and greased all the grease points every 12k (there were a lot!), and don't forget adjusting/replacing points and condensers, copper spark plugs only last a couple 10k miles, and constantly tinkering with idle screw through the year to keep it from dying/racing depending on the temperatures.

Hondas are like appliances compared to the old days.

Sam

[ganseg]

I am new here, so please forgive me. For people who are at 300 or 400k, do they run the semi-synth for 7,500 oci and this has worked? The 2005 car I bought had 175k and dealer oil changes on schedule. It is a southern car, so that should help. It freaked me out when i learned there was 2.6 qts and that it was semi synthetic. TIA!

[Willie Williford]

I always used full synth in mine. Starting at the second oil change, 15K.

[Eli]

Run whatever, it doesn't matter as far as engine longevity goes. Just be sure and change it.