[buster]

Hi all. My 05 now has 155k on it. Car runs great, but I have a question about the torque/hp/Vtec.

A friend of mine at work had an 03 Accord with the same engine. I let him drive mine and he said it felt sluggish at low rpms (between 2-3k). The car has always operated the same from when it was new.

I told him that I get the VTEC surge in the upper RPM range, around 4,500-5k rpms (approximate). He was telling me that most of the power in the 2.4L occurs at low rpm and that it should be smooth all the way through the RPM range. He was surprised there wasn't more power in the low RPM range.

It's always been my understanding that this engine, like many Hondas, don't see their true power until you are in the upper rpm range. Any truth to this? Thanks!

 

[outersquare]

the K24A4 and K24A8 had very even and wide powerbands, surging into higher RPMs is not really normal.
The current K24Z3 has true 3 lobe VTEC and thus it has a more peaky power curve.

you can try changing your air filter, spark plugs and maybe some injector cleaner.

 

[buster]

Thanks. I had all of that done. I'm going to check the plugs again. It's always been like this, I just thought his opinion was interesting being he had one before and thought my car responded differently.

 

[outersquare]

i see, how is your transmission fluid?

 

[buster]

The MT fluid should be changed. That is the one thing I need to have done. Car runs excellent, it's just something he noticed. I do notice a surge in power though around 4.5k rpms or so. Just a slight surge.

 

[outersquare]

that may not be a big deal then, plus automatic will feel different from manual anyways

 

[Fabb Capo]

Hi all. My 05 now has 155k on it. Car runs great, but I have a question about the torque/hp/Vtec.

A friend of mine at work had an 03 Accord with the same engine. I let him drive mine and he said it felt sluggish at low rpms (between 2-3k). The car has always operated the same from when it was new.

I told him that I get the VTEC surge in the upper RPM range, around 4,500-5k rpms (approximate). He was telling me that most of the power in the 2.4L occurs at low rpm and that it should be smooth all the way through the RPM range. He was surprised there wasn't more power in the low RPM range.

It's always been my understanding that this engine, like many Hondas, don't see their true power until you are in the upper rpm range. Any truth to this? Thanks!

Wait a minute I once read the Vtec in our cars was only for fuel economy, and didnt really have anything to do with power. I also have never noticed any surge of power when driving 4,500-5k rpms before. How come?

 

[Offbeat Oddity]

I always thought this engine had a pretty broad power curve and felt powerful at lower rpms.

One thing I'm curious about is the RPM range people typically are in and the usefulness of peaky power curves. I live and drive mostly in town with a speed limit of 35mph, so I rarely go past 2000-2500 RPM. Unless I take the highway to the city, I don't really experience 3000 RPM+, though on roads around here with higher speed limits, I do enjoy taking the engine near 4000-4500 RPM because the engine sounds and feels great there.

I guess unless you do a lot of highway driving/passing, a really peaky power curve wouldn't make sense, and though I've read a few people thought the 2.4 was peaky, I'd disagree. Perhaps it does make more power on top, but I'm rarely left wanting when I accelerate from a stop.

 

[Toshbar]

I feel a noticeable surge in power right at 2500 in my 2004 4cyl MT.

Does the guy with the '03 have AT or MT? AT will smooth everything out by design....being a slushbox.

 

[Keystone]

Your friend doesn't know what he's talking about. Internal combustion engines make more power at higher RPMs because the faster they're spinning, the more power strokes you get per second. Just look at a printout from a dyno run. More RPM = more power. Here's an example:

[/IMG]

 

[jshaw]

He may be thinking of torque, which for a 2.4L and this long a stroke, should be mid RPM range where it peaks.

 

[GenXer]

Yes, torque curve depends on the engine. I used to drive a car with a straight 6 which developed max torque at 1600 rpm!

My wife has an Element with the A8 engine and it definitely feels different than my A4 engine. Her truck seems to have smoother power delivery. Maybe it is due to the different cam and intake manlfold design in the A8. My car is more peaky...2800 rpm is when my intake cam makes the switch.

 

[04blkpearlcoupe]

Hi all. My 05 now has 155k on it. Car runs great, but I have a question about the torque/hp/Vtec.

A friend of mine at work had an 03 Accord with the same engine. I let him drive mine and he said it felt sluggish at low rpms (between 2-3k). The car has always operated the same from when it was new.

I told him that I get the VTEC surge in the upper RPM range, around 4,500-5k rpms (approximate). He was telling me that most of the power in the 2.4L occurs at low rpm and that it should be smooth all the way through the RPM range. He was surprised there wasn't more power in the low RPM range.

It's always been my understanding that this engine, like many Hondas, don't see their true power until you are in the upper rpm range. Any truth to this? Thanks!

It could just be the quality of the gas you're using. I've noticed over the years that sometimes the gas I get makes my car run sluggish. Costco gas used to be the worst but that was years ago. I almost complained to costco once because my valves started tapping loudly right after I got gas from them. I threw in some gas treatment ASAP and that fixed it.

 

[outersquare]

Yes, torque curve depends on the engine. I used to drive a car with a straight 6 which developed max torque at 1600 rpm!

My wife has an Element with the A8 engine and it definitely feels different than my A4 engine. Her truck seems to have smoother power delivery. Maybe it is due to the different cam and intake manlfold design in the A8. My car is more peaky...2800 rpm is when my intake cam makes the switch.

The K24A8 has an extra resonator chamber attached to the intake manifold plenum, yes it was supposed increase midrange power.

there's a bit more here about the manifold resonator design;

http://asia.vtec.net/Engines/K20Z/index.html