detonation with unichip

M

msp_213

Member
:
09 mazdaspeed3
ok need a little help. i have been hearing some detonation at about 5k rpm when im at w.o.t so i took it to a dyno shop to check it out and same thing when it hit about 5k it was detonating loud and the a/f was 12.1 from 5k till redline.on map A and stock boost. i dont know too much about what causes the detonating. did some searches but got no help. any help would be great.

what would caues the a/f to be 12.1 and how do i change it
and does that cause detonation or are they 2 seperate issues

mods:
turbo back exhaust, short ram intake, 1 step colder plugs, unichip
thanks
 
whats the timing like? I know you cant look at it, but maybe your unichip tuner could tell you.
 
when did you change your plugs? i would say the colder plugs maybe the culprit as you aren't running high boost or racing and they may have fouled with just daily street driving. switch to stock stepped plugs and see the diff.
 
What octane are you running? Are you flashed, and if so, did you specify that when you got the Unichip? 12.1:1 isn't necessarily bad, but it will depend on many things.

I would recommend running stock heat range plugs if you are at stock boost. I run stock plugs at 7.5-8 psi without any problems. They will give you a better burn and less chance of fouling.
 
First of all colder plugs (especially just one step colder) will NOT cause detonation. If they were fouled you'd get misfire and rough idle before you'd get detonation.

His AFR's are fine... I run as lean as 12.8 under boost for better power... this just goes back to the fact that you can't tune it yourself so you are stuck with what they put on. You need to get the tuner to pull some timing out.. and/or spend 500 bucks and get a JandS and not have to worry about detonation anymore as well.
 
Yeah... if you do it right you can run REALLY lean under boost and be fine... again all goes back to whoever tunes the vehicle, and I have to say that the more exposure I get to other tuners the more frightened I am for everyone who has their car tuned... a lot of people and places are "tuners" but don't know a cam sensor from a crank sensor... scary to trust that much investment over to someone else!

The best thing you can do to quell the detonation is go to the higest grade gas you can find, and try switching gas stations from where you usually buy it... Other than that, get it retuned. As long as your plugs aren't fouled I'd stay cold.. DON"T use a fine wire plug though... plain and simple only plug you should use in these motors in my opinion is the NGK BKR6E gapped to about 30 thousandths.
 
where you using 91 or 93+? not sure if it matters, but did you tell unichip if you were flashed? do you have a boost gauge? Have you tried the setup with the stock airbox?
 
Does anyone know if Mazda put a different plug in the MSP model? I would assume they put in something colder, but I have not confirmed that.


(very doubtful the plugs are the issue, even at stock boost)
 
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I agree that colder plugs won't cause detonation, but I do think that the stock plugs work much better at stock boost. I had horrible fouling issues with the BKR7E plugs.

Turf, what's bad about using a fine wire? Does it have something to do with quench areas?
 
thanks for the help. i run the ngk iridium plugs think they are bkr7iex. i run 91 thats the best we have i am going to try and take the intake off. the rep from unichip said that that it was tuned with the cai and not a short ram. as for timing what should it be? i have one of those programs to read the ecu's codes and it will read timing
 
Spooled said:
I agree that colder plugs won't cause detonation, but I do think that the stock plugs work much better at stock boost. I had horrible fouling issues with the BKR7E plugs.

Turf, what's bad about using a fine wire? Does it have something to do with quench areas?
Click to expand...

BKR7E is a little too cold and those will foul badly at low temperatures... you need to tighten your gap some when you get that cold... race engines actually use one plug for warming up and one for running... I use the BKR6E and obviously run large injectors (550's) and run rich when tuning or testing a new unit or so forth and have never fouled them out... so I know they hold up well under poor circumstances.

Fine wires tend to foul out very very quickly.. and once fouled can't be remedied... the iridiums are some of the worst plugs out there from a standpoint of that fine tip can lead to a hot spot and pre-ignition which is even worse than detonation. They also tend to foul quicker... and frankly when compared against a BKR6E plug at 2 bucks each there is NO reason to run them when they cost 8 or more times as much.
 
What are you guys running colder plugs at (gap wise I mean)...?
 
msp_213 said:
thanks for the help. i run the ngk iridium plugs think they are bkr7iex. i run 91 thats the best we have i am going to try and take the intake off. the rep from unichip said that that it was tuned with the cai and not a short ram. as for timing what should it be? i have one of those programs to read the ecu's codes and it will read timing
Click to expand...

The ECU code thing doesn't read fast enough to get a good timing reading.. and it will only read what the stock ECU thinks it is doing.. not what the Unichip is putting out...

The unichip claim blaming it on your SRI versus a CAI is a little bunk as they should have it tuned properly based on air temp and CAI or SRI won't matter if you are referencing temperature properly... You may get lucky and the SRI may help by being taken off.... but I don't think the stock airbox will be significantly cooler or that much closer to a CAI that the problem will go away... but anything is better than detonating... our stock internals are not very strong and it won't take much det before you'll be needing a new block.
 
HorsepowerFreak said:
What are you guys running colder plugs at (gap wise I mean)...?
Click to expand...

I run 26-29 thousandths on my plugs... never higher than 32 if I can help it.
 
TurfBurn said:
I run 26-29 thousandths on my plugs... never higher than 32 if I can help it.
Click to expand...

Do you run that small because of your boost level? I would think that as long as the plug can dissipate the heat quick enough to avoid hotspots, and it has enough power to jump the gap, that you'd want the largest gap you can for a stronger spark. I remember that I always gapped my colder plugs on the larger side to get a bigger spark. Was I wrong for doing that?
 
I always gap tighter because it helps keep plugs from fouling and it helps as boost rises... i only run a max boost of 14 psi right now... so I'm not doing anything crazy until the spring (then I plan to run minimum boost of around 20 psi and top boost of about 26 psi). By gapping them tight I make sure it runs well and never misfires, and overall I am very happy with the peformance. I've been leaving my car out at night and it has been getting into the 20's around here and the car starts on the first try most mornings, and the second try on the days it wants to be difficult. So I wouldn't call that much of a starting problem :).
 
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