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Discussion Starter · #1 ·
What would be a good air fuel ratio for daily driving vs full boost/ full throtte?

I am currently running 12.8 daily driving and 10.5 full throttle and am seeing a little black smoke out of my exhaust. I leaned it out to 10.9 and now only a little puff.

Also is it safer to run too rich or too lean. Oviouslly you wanna stay away from either.
 

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turbo94supra said:
running to rich is safer, gas milage wise with my car A/F is around 14
wtf????

running to rich is as bad.as running lean. I would not run anything below 11:1 at wot and that number would be at 1000+ HP. anything lower would be at 11.7:1.
 

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Boost4fun
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right. Too much unburnt gas is washing the oil film in the cylinders away. Try to never go under 11:1.. Better between 11.5 and 12 under boost, of course.
Under cruising conditions 14.7:1 is good.. Then the higher the richer..
 

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teh DJ
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just curious....what gear are you guys pulling when you're tuning the A/F?
 

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Boost4fun
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I do it in the higher gears like 5th or 6th.. Best way is with a datalogger and an O2 like Zeitronix or similar.
@Winnipegman
If you are rising the boost I think it´s pretty normal that it´s pig rich up there. You could tweak that out with a AFC or MAP ECU or so...
Gerd
 

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Winnipegman said:
Any reasons why my car would be running this rich stock?? Stock twins and injectors.
It is supposed to run rich in stock form!! Toyota runs the supra in the 10s A/F at WOT.

Rich is safe....... and you wont wash your rings away contrary to an above post.
 

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Boost4fun
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So you are saying that 10s are good for the engine?
I doubt it and it is also a big hp loss. The AFR is (in my opinion) always a balance between burn temps and power.. The richer the less power. The leaner the more power.. Right?
I still think that with a very rich conditions unburnt gas will go into oil and thin it and wash it also away of the cylinder walls partially. Am I wrong?
 

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Discussion Starter · #9 ·
@ 10.5 A/f Ratio 13psi my car does a 13.8 1/4 mile
@ 10.8 A/f Ratio 13psi my car does a 13.5 1/4 mile

I have an emanage Ultimate for tuning purposes.
Am currently going single so the car is out of commission.

Will a higher A/F ratio at full throttle be good for all gears?
Or should it be richer the higher the gear?
like 12.0 in first
11.8 in second
11.6 in third
11.4 in forth
11.2 in fifth
 

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Boost4fun
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I don´t know how you will handle a different A/F in different gears....
Sure thing is: At WOT the higher the gear the greater the load and so the heat will be. In principle your thought is good but I doubt it can be managed.. At least not with stuff I know.
I have experienced that at AFs over 12 the EGTs are popping the roof and endangering the pistons and turbos...But also here-This is not such a big deal in the lower gears since the WOT conditions there lasts only seconds and not a minute or more.. Different thing on a track of course..
Gerd
 

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Old School
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Winnipegman said:
@ 10.5 A/f Ratio 13psi my car does a 13.8 1/4 mile
@ 10.8 A/f Ratio 13psi my car does a 13.5 1/4 mile

I have an emanage Ultimate for tuning purposes.
Am currently going single so the car is out of commission.

Will a higher A/F ratio at full throttle be good for all gears?
Or should it be richer the higher the gear?
like 12.0 in first
11.8 in second
11.6 in third
11.4 in forth
11.2 in fifth

Your trap speed would be a much better indicator of power differences between various A/F ratios.
 

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i try to run an 11.5-11.7 on a street tune at WOT, on race gas and higher boost at the track i always want it somewhere around 11.9-12.1
 
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