"feeling" the torque curve

[xluben]

are you supposed to be able to "feel" the torque curve as you drive?

i just got my intake put on and it seems like i can feel the torque drop off after 4k rpm's.

i have an ebay model but it feels like this (aem cold air intake):

it's like i'm getting good pull until just over 4k and then it seems to almost level off.

i can only feel this in 1st gear, i don't think the rpm's rev quick enough past that.

is this normal?

would converting to SRI config. help the top end level off?

or is this all in my head?

 

[shavedaccord]

typically SRI gives you better low end and CAI is top end.

 

[angelplus]

typically SRI gives you better low end and CAI is top end.

+1 on that

On my car, I feel that little torque curve at like 4500 - 6000rpms its a great feeling lol most of the time you dont feel it though

 

[Totalimmortal]

My car rips past 4000RPM

 

[BlkCurrantKord]

4k is the magic crossover...yay!

Mine peaks in tq before 5k rpms but holds over 110lb/ft fromjust past 4k rpms to 5300 rpms.

 

[Totalimmortal]

I wasn't always that way. I'd say I noticed it being more pronounced after the header install.

 

[xluben]

i can definitely feel the torque peak and then drop off just before 4.5k

it's like the push-you-into-your-seat feeling (not a lot, but you know what i mean) and then it feels like i let off the gas (a little bit)!!!

i sure hope my top end didn't actually decrease with the intake!

maybe that peak just got better, so the drop off is more noticeable. once the roads dry i'll do some 0-60 runs to see if anything's changed.

i remember before it used to seem like the acceleration kicked up a notch right were it seems to be decreasing now

also, i'm having a CEL keep coming on that read "too lean/rich fuel mixture"

my mechanic thought it could be dirty injectors not giving me enough fuel. could this be causing the drop off?

 

[Totalimmortal]

I doubt the dirty injectors idea, check your plugs.

 

[xluben]

I doubt the dirty injectors idea, check your plugs.

you mean for the code or for the torque?

i don't see any way the plugs would have anything to do with the CEL code

 

[AFAccord]

typically SRI gives you better low end and CAI is top end.

In fact, the opposite is true.

Take a trombone for example. Pull the slide almost all the way out and you have a long tube. Send reverberated air through this tube, and you get a low pitch sound. Now pull the slide all the way in, and your tube is much shorter. Send that same frequency of reverberated air through the shorter tube, and you have a much higher pitched sound.

This is the EXACT same effect different intake lengths (SRI vs CAI) have on a motor, but to understand this, you have to understand harmonic resonance. There isin't a very easy way to describe this, but there is an exerpt that you can read below to possibly help you understand, or just possibly confuse you futher. You can read it and learn, or otherwise just accept it as fact.


" If, at any one constant throttle and constant rpm, you could adjust the LENGTH of the intake system, you could find a correct length so that the REFLECTED pulse of air from a closed valve, hits an open intake valve at an exact moment as a normal incoming pulse of air. This will have the effect of boosting power, as more air will be forced into the cylinder...at NO cost whatsoever in loss of energy."

This example is for a CONSTANT throttle and RPM, so a typical well designed intake has a particular frequency (engine rpm) that its harmonic resonance is most effective for the overall motor. Several car manufacturers have made attempts at 'adjustable' intake lengths, including Honda. This is where engines like the F22A6 get their dual runner intake manifolds from.

So how does this affect you? Well, if you choose to use a SRI on your 2.3L accord, the piping is shorter, with less volume, and has a higher effective harmonic resonance. Likewise, with a CAI, the effective resonane of the intake is lower. So those with a CAI will experience better low and mid-range torque, whereas those with SRIs will experience a seemingly better top-end experience.

I say 'seemingly' because the 2-3hp top-end gain you feel is exagerated by the 4-5wtq loss in the mid-range.