Helo58

After previously running a best of 13.2@111.9mph in the quarter mile, I replaced the K&N setup that came on the car when purchased. The stock intake, afe dry drop-in, and stock MAF sensor (cleaned) were installed by the dealer during an oil change at no charge to me.

During my most recent time at the track, I ran a 12.7@109 in the quarter mile on the same track with a DAs within 200ft of each other. My 60ft times improved 0.2 seconds to 2.0 flat with the same air pressures and launch method and my ET improved 0.5 seconds.

Some of this I expected, but I was disappointed to see the drop in trap speed (which was unexpected). To the best of my knowledge, nothing but the intake changed. The car hooked up, my shift points were the same, same fuel, same amount of fuel in the car, etc.

Most drag racers say that a drop in trap speed means a loss in HP. I thought that the stock intake was supposed to be better than a cone filter. Time says it is, trap speed says I lose power... I am sure there is a logical reason for this, so anyone with lots of experience and knowledge in drag racing please explain how my ET can improve but my trap speed gets worse. I don't have the experience to come to a definitive conclusion.

Sylvan

iTrader: (6)

So it looks like you may have lost top end horse power but gained some low/mid range torque that helps get you off the line quicker.

Ltaboso

maybe it is:
K&N filter=more air,breathes better...but sucks in hot air after a while so power loss....

drop in=less air,but sucks in a bit colder air because of the enclosed design,no power loss.....

i wonder if having a takeda intake set up would be having the best of both worlds?

Helo58

Sylvan, those were my thoughts as well. Many years ago in the Honda community, this effect of more torque/less HP was noticed when changing intakes.

Ltaboso, I would agree that the K&N likely breathes MORE but probably not better. The heat soak idea has been one that has been hard for me to accept personally because I have never noticed it quantifiably. During track days after multiple runs, some with cool down, some without, my times sometimes improved after prolonged idling in the staging lanes on 90+ temp days. I think the car prefers consistency in sensor parameters as much as a range of ideal sensor parameters. Hot to cold seems to throw the car off more than all cold or all hot. I think with huge swings in parameters (going from hot to cold), the car "plays it safe."

It is my suspicion that turbulence in the intake over the MAF sensor has some part to play in things. Aftermarket intake airflow not being equal to stock airflow.With returning the stock intake, shifts, downshifts, throttle response, etc. have all improved at all rpms. I am sure various drivers have their own experiences that may differ from mine, but I think that Sylvan's interpretation of more torque/fewer HP is where I am leaning.

FFM

So you ran a half a second faster in the 1320, not seeing a problem here haha. But yeah, generally a tenth reduction in 60' lends to two tenths in the ET so by shaving that 60' down I would have expected the results you are seeing. Wouldn't be overly concerned with the trap, track times don't lie, cars quicker

Helo58

TRUST ME, I am not complaining about picking up half a second in the 1/4 haha! I am just trying to understand why I am quicker (acceleration) but not faster (velocity).

Nice to know the rule of thumb regarding 60' times. Now if I could only get a sub 2 60' time... That means a 1.8 60' would put me at 12.3-12.4. I can deal with that!!

caymandive

iTrader: (2)

Have you considered wind speed and direction? With some tail wind I pick up a few mph. That could explain your trap speed differences.

Quadrphnia

There is only one solution.




Sell me your stock intake.

Helo58

Thanks for the reply. I don't remember it being that windy, but I suppose that could be a contributing factor. Historical weather shows a wind of 3mph gusting to 6mph blowing NNE. The track runs from east to west, so if anything it was a headwind.

I have been searching for possible solutions and I really do appreciate constructive suggestions. I believe the considerable amount of input here on the forum regarding intakes not making power, but I am hard pressed to find another cause. I love RR Racing's suggestion of using a VBox coupled with some 60-120 pulls to evaluate the engine, but I don't/won't have a VBox to use.

The variance in quarter-mile speeds and vehicle weight can be used to approximate the horsepower difference and it is at least 25-30 horsepower. I don't know how much hp can be potentially lost due to the ECU managing parameters, but I would be very interested to know.

Helo58

Haha, I like the tenths I picked up in the quarter more than I dislike the loss of trap speed. I wish I could have both.

Maybe when/if I get headers, I will part with the stock intake.

zazzn

When you get a better 60 foot, I usually see slower MPH, but better ET. Seems normal to me

Quadrphnia

I hear ya and totally understood.
I adore the sound of the K&N but I've never experienced otherwise as mine was on the car when I bought it.

Helo58

Yeah, I loved it too. Mine came with the K&N, and a Borla cat-back with no resonator. I found the airbox/intake from an 09 ISF in a salvage yard about 70 miles from my house and bought it. I also called Borla to order the resonator and then had it installed. It is now proper for daily driving duty, but I occasionally miss the "loudness."