can someone help me clarify this, i asked if someone could post my dyno chart..but,no one offered?..so i asked if someone could tell me what the a/f ratio should be ?.whats considered high and whats considered low?..mine is right around 12.1 to 12.5.til 6500 then 12.0...all the way across the board..i made sure when i had the car tuned i asked for a conservative tune,,but it seems that after i have read all,, many many threads..that the best a/f/ ratio is around 11.6 across the board..sooo i am wondering why mine is where its at? thanks to anyone that could help me figure this out?..if its not right i want to take it back to where i had it tuned,,plus i hope i have not done any thing that would hurt my motor,,i only hit wot a few times after i had it done just to feel the difference,,,it does not ping at all...i know that when i had it tuned the person used a thesascope to listen to the motor just to make sure...i think the place does good work i just want to claify things ..thanks,,
a/f ratio i really need to know,,,
- Thread starter redfire004
- Start date
The 12 to 12.5 readings, how were they taken? If a tailpipe sniffer was used, the actual readings are probably a little richer than shown, up to .5 point,
so your 12.0 reading could actually be 11.5.
12 is not bad.
These motors run well in that range, but 11.5 to 11.8 is safer and many people are more comfortable with this number.
I wouldn't worry about any damage because of this setting now.
Last year I ran mine for months up near 13 and it's still running fine.
Dana
so your 12.0 reading could actually be 11.5.
12 is not bad.
These motors run well in that range, but 11.5 to 11.8 is safer and many people are more comfortable with this number.
I wouldn't worry about any damage because of this setting now.
Last year I ran mine for months up near 13 and it's still running fine.
Dana
I think its just personal preference from the tuners standpoint. personally, I like to be below 12. I think all will agree though that above 12.5 is bad news.
peace
peace
for some reason I am running at 10.0
12.0 - 12.5 throught the tailpipe is plenty safe IMHO. Like said earlier, that would be closer to 11.5 - 12.0 if taken before the cats. I like to see cars in the 12.3 range or so from 2500-4500 and then get a little richer up top. This way you'll get maximum torque and have great driveability.
lightning@jack said:
I'd look into that.
If the measuring instrument is correct, the tune is WAY fat.
Dana
Does the cobra have oil squirters? If so I'd say 12.5 is fine top end... Might be a little on the lean side but I wouldn't think you'd detonate until 13.2 or so -
Also, at what temperature did he tune?
Also, at what temperature did he tune?
SICKBOY said:
I believe it's a technique used by some rice rockets and well designed motors designed to be blown or turbocharged. Oil squirters provide oil at the bottom of the pistons and is used to cool them in high boost applications. Personally I've never had a motor apart that had them, but I believe the Mazda Miata motor is built like that.
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Dana said:
I was in the 10s stock at the dyno last year. I assume that my cat back and FIPK has leaned that out a little. I need another dyno....
In general,
10s- way too rich
11s- most people's A/F of choice
12s- for the gamblers
13s- Engine death is near.
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Joe D said:
I'm not sure about the miata motor, but yeah you're correct it's a technique used on high boost applications to keep EGT's down. It's on a lot of first generation DSM engines, the SRT-4 engine, and a few other here and there. They do provide a lot of protection for bad tuning, overboosting, and general engine protection.
If the cobra had oil squirters I'd imagine the 7 and 8 piston would be a lot more durable.
so ... sickboy, if you were trying to make me sound like a dumbass then position yourself directly in front of the mirror.
I am in the 10s with a ported blower,pulley, tune, etc. Running way rich, suppose its better than real lean.
ttt
i believe he removed one of the o2 sensers and put the sniffer there before the cats, i will give him a call tomorrow and ask him to redo it and richin it up a tad..i would think his dyno machine would have told him if it was running kinda lean?.but who knows,,i think its probably ok but i agree i would rather be a the safe side thanks for the replys,,,
i believe he removed one of the o2 sensers and put the sniffer there before the cats, i will give him a call tomorrow and ask him to redo it and richin it up a tad..i would think his dyno machine would have told him if it was running kinda lean?.but who knows,,i think its probably ok but i agree i would rather be a the safe side thanks for the replys,,,
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