Give us a st-st-stutter and stumble update (K&N owners)

[Grimace]

I was reading some consumer reviews on Edmunds and I saw someone mention the stumble issue at ~3500 RPM that we've all read about here.
Sometimes on an automotive forum, if one person claims to have an issue, everone suddenly has it (the "Chicken Little" syndrome, I like to call it). Please no one take any offence by this. So it picqued my curiousity when I read this review of the car from (I'm guessing) a non-forum member that his car stumbles @ 3500 RPM.
Anyway, long story short, I am curious if those that have done the K&N mod are still hesitation- and stumble-free. Do you believe the problem is cured? How long has it been since you made the mod?

 

[AGR]

There is no question in my opinion; the addition of the K&N has improved that issue. It still shows up sometimes, but I would say 80-90% is gone.

 

[ArkosP5]

Check the Forced Induction Board. The turbo guys have found that the ECU pulls fuel at that rpm. I don't remember offhand why, ...

 

[Grimace]

OK, I did a search (for Mazdaspeed + fuel + ECU) and I couldn't find anything in the 3 threads that popped up in the FI board. Maybe I'm using bad search terms?

 

[Limited Edition]

Grimace.
i wish it was completey gone but for me, with the Ractive Cone Filter, it hasn't been cured yet. I still get the hiccup if i acceleration in 5th gear hard then back off the throttle suddenly. It's a pretty big jerk that everyone in the car can feel.

 

[Grimace]

L.E. -
I would say that is fairly normal in most cars. My car does it too, and so have other standard-transmission cars I've driven. I think it is because of a lack of slop in the driveline (that can be absorbed by a automatic transmission driveline).
Specifically, when you are accelerating through the gears, do you feel a little hesitation/stumbling around 3500 RPM?

 

[OrangeSpeed]

I just put mine in and only had it happen once and it was less noticable than before. It is alot louder as well..... only thing is even though my sensor appears to be all the way in there, it stumbles at idle when the fan kicks on anyone know why?? Im curious why it would do that, i dont feel a loss in power. But I just need a boost controller im tired of these swapped guys beating me haha. Later

 

[HELMET]

I beleive what Grimace is talking about is called backlash. One has to be smoother on the accelerator. I beleave the poly bushing motermount will fix your troubles Thats my next mod.

 

[HELMET]

I'm also going to poly bushings on the sway bars. My ride sounds like a bed in a cheap hotel...

 

[Limited Edition]

L.E. -
I would say that is fairly normal in most cars. My car does it too, and so have other standard-transmission cars I've driven. I think it is because of a lack of slop in the driveline (that can be absorbed by a automatic transmission driveline).
Specifically, when you are accelerating through the gears, do you feel a little hesitation/stumbling around 3500 RPM?

I don't think this normal, because it has never happend to my previous civic 5 spd nor my sister's prelude 5 spd as well. The jerk is pretty noticable if i were to back off the throttle sudden. Anyway, through the powerband, there's no hesitation around 3500rpm, but from 4500rpm to 5500rpm seems like there is a loss isn't much of a power gain in that range. I feel most torque at 3500-4500rpm ~ this range is best for passing on the highway

 

[Grimace]

The Civic and Prelude may have had harder motor mounts. Just a guess.
I know the motor mounts in my car are soft enough that I can REALLY rock the engine back and forth a lot if I play with the accelerator a bit. It can be really bad, snapping your head back and forth and making the whole car buck. I've just learned to not lift off the throttle so quickly, I kind of "roll" my foot back on the ball of my heel.
Of course if its an emergency and you need to get on the brakes quickly, don't worry about being smooth!
(Thanks HELMET, backlash was the term I was searching for.

 

[MikeyG_U2]

are there replacement motor mounts for our MSP's?? Has anybody tried them out yet? I'd be curious about how much more vibration makes it into the cabin. Our engine's aren't the smoothest things out there. Honda 4's are usualy a lot smoother, so they can get away with stiffer mounts....