Knicksfan

For those that have driven both, do you feel the difference between the 2005 (270hp) and the 2003/2004 (235hp) engine?

yaro1

New engine?

I thought they just changed a little gearing or timing or something. Maybe I'm wrong, but I don't think its a new engine.

Sorry to nit pick, just a little

bareyb

Well it's not a BRAND new engine, but they did finally upgrade it to include variable valve timing. I've driven both vehicles and I can't tell any difference at all.

looknow12

They added variable valve timing which increased horsepower to 270hp. VVT should make the engine much smoother all around. It also improved engine emissions from LEV to ULEV II.

bunka

The only change is the variable valve timing, right? So, this is the same engine and the only difference is that as the RPM's increase, the valves are now dynamically adjusted so I doubt there would be any instantaneous feedback. Rather, the power increases would simply occur a little earlier in the RPM range and more power on the top end, right? So, from zero to 3,000RPM you probably would not see any difference. Anyone have a 2003 and a 2005 they could test this with? Maybe a Luz SUV drag race to see if there really is any difference from (say zero to 1/4 mile)? From reading the specs it seems like the new one is faster but that a "hot" unit from the facotry may perform as well. If you guys do "race em" please take some pics and maybe a video or two. It's getting a little dull over at teh Acura TL site and I nbeed something to post...

TeCKis300

The addition of VVTI allows for improved volumetric efficiency across the powerband. No longer are the cams statically timed. They can be optimized for different loads and fuel efficiencies in differenct parts of the powerband.

What does that give you? Improved torque production throughout the powerband. Prior to VVTI, the cams were probably timed for torque in the lower rpm band. With VVTI, the cams can also be optimized for better VE, hence torque in the upper RPM band. It is in the upper RPM band where peak HP is made (torque * rpm / 5252). With more high rpm torque, more peak HP is made which reflected in the HP increase.

These improvements can best be appreciated during spirited highway passing, hill climbing, or full throttle acceleration where the higher rpm band is utilized.

looknow12

Doesn't the GS300 or 430 have direct injection now also?

looknow12

Oops wrong forum room :-)