Hi all!

I'd be really apreciate if somebody who understands more than i do in logs would look into my logs to possibly get an idea of what is wrong with the car/map.

The problem is that the car jerks considerably in low gears (especially 1 and 2) when i'm easy on acc pedal and low on rpms, when it is basically changing between braking by the engine and slightly pulling (read cruising).

The setup:
Cobb AccessPort (MazdaManiac tuned map 4.0.5)
HJS Motorsport Metal cat
GReddy SP2 Catback
K&N Dropin filter replacement (recently cleaned and reoiled)
new coils
new ignition wires
new Exedy OE clutch kit
the rest is stock

AccessPort log attached.

The problem can be seen between 0:40 and 0:46 seconds and than again between 0:59 and 1:10.

Actually it jerks once between deceleration and immediate hard acceleration and vise-versa.

Any input would be greatly appreciate!

 

Who are you calling a car jerk? :P

Also, I see no logs.

 

no logs.
When did you install the most recent tune?

 

LOL

Yeah, my bad. Attachement was filtered, because it haven't been packed into .zip

 

Re-attached the log.

Last map was loaded rougly a year ago. Why?

 

a lot of cars do that when you are at idle, there was no slight cruising about it

which maps did you modify?

 

I didn't modify anything - Cobb doesn't make Access TunerRace for European cars, only pro tuners with appropriate software can do that. So it is a MazdaManiac's tune.

 

So are you saying it can't be cured?
It was not an idle cruising, but a close to idle cruising if that makes a difference.

 

Is this a new thing? It looks like you're lugging the engine.

 

Regarding the jerkiness on throttle tip-in and tip-out, I think that can be changed slightly with the rpm delta tables, but mostly it is the nature of the car.

 

How long did you wait before putting the K&N back in, and how much filter oil did you use?

 

You mean the engine? No, it is the original engine with 43k km on it.

 

The filter was dryed for 24 ours after wash. We've oiled it with enough oil for it to change the color to red on both sides.

 

Yes it makes a difference: use a lower gear.
Did you ever clean the MAF\Iat sensor?

 

jerking is at 1st and 2nd gears, it will be hard to use lower than that

I recently cleaned the throttle body, it helped a bit, but it still jerks.

If you give me some link to a MAF/IAT cleaning instructions - i'd give that a try as well.

 

http://www.rotaryheaven.net/showthre...ighlight=clean

Driving below 2000rpms is highly discouraged anyway. Useless stress on the engine.

 

Thanks for the link - will do that over the weekend.

 

We're here to help, mostly!
It takes less than 5 minutes to do it.
How are your engine mounts?

 

It won't make any difference. You are transitioning from very lean decelleration with very small throttle angle input and the engine management system cannot pickup and respond to that quick enough. The answer is to stop doing it and use your clutch foot instead.

 

Hence the previous comments. Nobody cleans the MAF here so it's good practice anyway.

 

Clutch is the way i do it to prevent jerking, but since 8 is not the only car i drive (drove) i know that with the other cars it is not normal.

 

That is normal for the RX-8. You are terribly lugging the engine since it produces no torque down there.

 

Thanks for your feedback, Jeff!

Have you looked into actual log attached above? There's a WOT in 2nd gear and i can be wrong, but i think it should read 100% calc. engine load, right? and it is not 100% until mid or mid-hi revs...

P.S. Love your avatars

 

BTW, I've sent you a new set of logs for your review like 3 weeks ago, will you have a chance to look at them any time soon?

 

CalcLOAD can be as low as 88% at WOT on some cars.
There are several parameters that go into calculated load.