i put in the K&N drop in filter last week and i noticed loss in power, the gas pedal felt heavier and i felt decrease in gas mileage. I did reset the ecu but it still didn't feel right.
Dyno'd my car today
STOCK max= 238.8 hp and 234.6 ft-lbs tourque
K&N =234.3 hp and 228.8 ft-lbs of tourque (= big LOSS)
will post graphs tommorow

i want my money back for the filter

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black

 

Be care ful with dyno info-outside air temp can really affect the readings. I know from experience you can lose badly on a hot day but look like a winner as the day cools down. Its hard to remove the air temp variable.[img]/w3timages/icons/frown.gif[/img]

03.5 Sedan/B. Silver/Prem/Winter/Aero/Tint/Rims
69 Chevelle Hard Top BB/4.11's/Posi

 

I noticed a dramatic drop in fuel mileage and a change
in performance when I put mine in. It wasn't until I did
a 13 hour battery disconnect that the car started running
"right" again. Gas mileage returned also. How did you
reset the ECU?

2003 Twilight Blue Sedan 5AT, sunroof, leather,
splashguards, GG red 7 wire Hypergrounding kit, 350Z intake duct(soon), K&N filter.

 

I build Diesel engines , and when we dyno the temperature and moisture in the air really affect readings as IQ9 mentions, even engine temperature makes a big difference, just before the thermostat opens and fans kick on for engine cooling, up to 10 or 15% power loss is not unussual.
I would re-dyno , and if you can duplicate the same climate as your original reading , it would be a plus.

 

A dyno chart where it made HP?



80829-Dyno G35C KN 3rd gear.jpg

 

i have some (about 30 pulls on 3 different dates with 8 or so different mods) experience with this ECU and this engine on a dyno, and I will tell you that the only way to get an accurate hp reading on a dyno is to reset the ecu and drive for a couple days after a mod before you dyno. this means, run one mod on the dyno, then make another change, run for a few days, then dyno witht eh new mod.

But to get an accurate comparo, you need to do a full reset before each run which can be time consuming on the dyno rack at 30-50 dollars/hour

personally I think I got mo better mileage with my kn drop in as I am seeing 26 mpg in my 6MT sedan now.

Better Life thru Chemistry

 

heres the dyno, run on the same day...............
i had the K&N in for 1 week and reset the ecu but i could tell that the car was not upto par, i was losing at the pump too.
here's the proof

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black

 

how do i post the dyno pic/file?

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black

 

Make sure that the file is under 100K. If you can't do that, then post it on imagestation and make a like to it..

- Don't argue with idiots. They will bring you down to their level and beat you with experience.=P-

 

.

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black

80935-baseline.jpg

 

sorry that was the baseline
here is the K&N run

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black

80940-K&N2.jpg

 

blue is K&N max hp is 234.3 tq and 228.8
red is stock max hp is 238.9 ans tq 231.1ft-lbs
loss of over 4hp and 3ft-lbs

pulls were done on the same day with the K&N being on for 1 week and ecu reset.

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black

 

Be careful jumping to conclusions on a dyno, especially a single dyno on a single day. They're not terribly precise instruments from run to run. Furthermore, the typical margin of error on a dyno is larger than whatever gains you should expect from replacing an air filter (especially if the stock filter was relatively new). That should be 2 or 3hp mod at most. The margin of error is at least twice that. You could have had a reading that gained 4hp and it wouldn't really prove anything, you'd need to get an absurdly high number for this type of mod to feel confident that it makes power. Finally, keep in mind that a dyno does not reflect real driving conditions, especially for a modification to a ram-air intake. On a dyno, there's no air being pushed through the intake by the forward motion of the car, it's all being sucked in by the engine from the back of the filter. One filter might be better suited to "motionless driving" than another, but not as suitable for the road.

I won't go into things like computer chip adaption, or "breaking" the oil-based filter in first. Hell, maybe one filter's material works better in certain temperatures than the other.

In short, the dyno doesn't provide much reliable evidence of anything in this context. There's just too many variables and the difference in power simply isn't going to be large enough to easily discern.

-Jack
Obsidian '03 G35 Sports Coupe
Titanium '03 MX-5 Shinsen #532

 

your points are well taken but allow me to repsonse.
the reason i did the dyno in the first place was because after the K&N was dropped in the car felt sluggish, i felt that i was losing power and torque. Hence i dyno'd the car.
I had 3 pulls with the stock filter and got within 0.1 on every run for HP and only .8 difference on the tourque curve. WIth the K&N, the numbers droped by 4 on hp and the same for torque. The temperature factors are removed since they were done on the same day and reliability of the runs i would say are pretty good since they were within the above mentioned decimal points. Sure there could be many other factors involved but that is conclusive enough for me to remove the filter. I agree with no air being pushed into the car however, 3 large fans were blowing some air, not the same as real driving conditions but some.
From all this, I think that i can say that the K&N drop in filter did not work for me and my car and was a waste of money.

03 G35 coupe SS (GD) 6spd everything but navi
02 QX4 pearl white
00 528 Silver on black