Whenever I throttle-off in gear at medium or high rpm, the car abrubtly decelerates

Also whenever i am in 2nd or 3rd at say 3-4k rpm and put on the gas, there's the slightest of hesitation instantaneously right as i do so. so the car doesnt really seem to respond for a small but noticeable fraction of a second. When it does respond, it seems initially stronger than proportional to throttle input, but then settles down. This all happens very fast but is noticeable.

This is my first rotary but I've had the car for over a year now. Up till now I figured that I would just adjust to these issues, which dont' happen often in daily driving.

HOwever, I was wondering if anyone can tell me if these are normal phenomena, normal for rotatries or normal for just any manual transmission?

I never really associated throttle hesitation and the rotary when i was thinking about buying the car, but then again im not sure as to what constitutes normal hesitation. If possible can someone explain whats going on in the engine to produce these phenomena?

The reason I bring this up is that it was raining at the track the other day, and I wasn't really driving the car hard, so it was in 3rd at ~30mph on an acute right hand turn, when i started to put a little gas on right after apex, that small jump in response spun a rear wheel for a tiny bit.

 

doesnt sound especially unusual to me. what cars are you used to driving that dont do this?

james

 

well its my first mt car. the auto trans ive driven, i couldnt tell

 

that explains it! you will adjust in no time.

james

 

The deceleration sounds like engine braking which is normal in manual transmissions (I don't know of many if any auto trans that do it).

 

its incredibly abrupt after i let go of the throttle... the car sharply jerks forward

 

normal...you have flywheel, clutch, gears, and wheels all locked together. no rubber banding torque convertor.

 

not sure about the whole decelleration thing.....sounds weird....but ive experienced a little bit of abruptness when i accelerate....basically when i start accelerating and initially get off the brakes and role on the throttle, the car tends to jerk a bit as i first push the throttle down, its kind of unsettling. Havent had a chance to track it yet, this is just day to day......ive raced competitivly for 9 years....never really felt this before....not a big problem....just something ive noticed.

 

just try accelerating to 60 in 3rd, then removing your foot off the throttle quickly... thats when i get the abrupt deceleration thing. im thinking more and more thats just a normal part of manual transmissions...

the nonlinear acceleration thing after small throttle input, however, im not as sure about.

 

its probably amplified from throttle by wire system. I know the PCM has algorithms to prevent bucking, but it doesnt work well. It may only activate between shift, I'm not sure. I drove my roomate's STi all day today (my car is AWOL at the moment :-/) and it was much smoother. Tap the gas on a toe-heel downshift and it's smooth as hell, something that takes awhile to learn on the 8.

If what you getting is what I'm talking about, you'll get 2 or 3 good "bucks" out of it at mid-rpm's if you dont modulate the clutch, not the "nosedive" you get from a high-rpm throttle release.

 

Can't speak for the 8, but I don't think your problem is related to the engine. I don't have the hesitation you speak of when I autocross in my 7. I do have 3000rpm hesitation sometimes, but that's an FD specific problem.

 

Ok, the deceleration is engine braking in a MT car.

As far as the non-linear acceleration, I've noticed this, too. The throttle is drive-by-wire, which means that you don't have a cable from the gas pedal opening the throttle body. Instead, you have a sensor finding out how much gas you want to give it and then the computer opens the throttle a certain amount based on that.

What I've found is that as you roll on linearly from no throttle to full throttle, the throttle body opens much more quickly, much sooner. It really aggrivates me, to be honest. My suspicion is that Mazda was trying to trick dumb consumers into believing that the car was faster than it was. See, a lot of people would never consider putting the gas pedal all the way to the floor, even in an RX-8. When they're at partial throttle and it accelerates well at lower rpms (like if we were at full throttle at low rpms), they'll think "wow! this car must be fast! I can't imagine what it would be like if I pressed the pedal all the way down! I shouldn't do that, it might be dangerous...".
Where it really aggrivates me is when I go from full throttle (lower rpm acceleration) and roll back as I approach the speed I want to level at, it keeps accelerating like I'm still at full throttle until I just about pull my fool all the way off the pedal. I don't like the non-linearity one bit.