Dwight, I've been schooled by experts in engine technology, like my friend who posted just previous to me, that torque doesn't matter, So why should I want an engine that makes more torque if it means I have to run 91 through it instead of 87?
Reg, it's a rework of the existing 3.6 with additional technology and more aggressive power tuning. It's not a whole new engine.
if it requires technology and manufacturing investment, it might as well be a whole new engine. you are talking about switching materials, finishing processes, specifications. generally in manufacturing engines, it sometimes is based on the bore centers and such. you mess with the metalurgy of an engine, and the cam drives / valvetrain, it pretty much is a new engine.
From an operations perspective.....once you have divergent parts numbers, its a whole new engine too, especially for the people who need to stock parts.
...and is also more in tune with what most traditional GM buyers would want in a car.
.............15-20 years ago.............
these days i doubt it matters. people want what is consistent with the times.
Torque does not matter if, and only if, you can change gearing instantaneously, continually and through an infinite range. That is not reality, at least not with today's transmissions. In any particular gear, the torque multiplication is the same throughout the rev range. Today's best automatics only give you about 6:1 to 7:1 ratio spread to play with. An engine whose torque peak is further removed from the cruising rpm is likely to require more downshifts more often.
Reasons for using 91 octane in exchange for higher compression is as follows:-
- A $0.20 difference in gas price (per gallon) at $3 a gallon is quite well tolerated by owners of luxury vehicles.
- The increase in compression yields improvement in MPG numbers
- Higher torque at lower rpms allows the vehicle to accelerate more quickly without having to trigger a downshift. This in turn improves the perceived refinement level by allowing a more relaxed operating speed in typical driving.
and then one idiot pumps 87 in his tank and all hell breaks loose.
the engine must run fine on 87, if it performs better on 91 than so be it. America has too many idiots to trust them to put 91 in consistently or willingly.
Edited by regfootball, 30 October 2010 - 11:53 PM.