AFR's vs rpm... And timing
03-14-2008, 05:49 PM
#1
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AFR's vs rpm... And timing
So I got my civic tuned last week. Its a stock d16z9 (same as d16z6) with a saab t3, log mani, fmic, blah blah, the usual stuff. I use crome free, freelog and a lc-1 wb. At the dyno we mostly tuned the boost part, and made sure there was no knock (dont have money to sit on the dyno tuning all part throttle maps). I have tuned most of the low cam part throttle myself, around 14.5-15 at cruise, rising ut to about 12 into boost transition. However the high cam part throttle maps are pig rich (mostly 11's, but also even 10's). I did most of the tuning in the low cam maps ust by adjusting the offset, so I wonder why the high cam maps are so rich? Are they supposed to be this way? All I can find when I search is AFR vs MAP never anything about AFR vs rpm. Am I blind, or is it just a dumb question? Should the AFR be the same at every rpm through the whole column?
Another thing that makes me wonder a bit is that we detected a slight trace of knock at 10 psi at the first pull with my basemap. I had pulled 1.1* per psi, so I was at 16* at redline. AFR were good, maybe a bit on the rich side, about 11. So we pulled 3* through the whole map, and the knock was gone, the power still the same. We pulled another 3*, and I had lost a whp or two, so we left it there, thought it should be on the safe side of the flat spot. I come home and take a look at some of the bins at xenocron, and I have 6* less timing than the most conservative map I can find. WTF? Are there so much difference between engines, or are there something weird going on? I set my base timing before I went to the tuner, so it should be ok. Is this ok, or should I start worrying about my valves?
Another thing that makes me wonder a bit is that we detected a slight trace of knock at 10 psi at the first pull with my basemap. I had pulled 1.1* per psi, so I was at 16* at redline. AFR were good, maybe a bit on the rich side, about 11. So we pulled 3* through the whole map, and the knock was gone, the power still the same. We pulled another 3*, and I had lost a whp or two, so we left it there, thought it should be on the safe side of the flat spot. I come home and take a look at some of the bins at xenocron, and I have 6* less timing than the most conservative map I can find. WTF? Are there so much difference between engines, or are there something weird going on? I set my base timing before I went to the tuner, so it should be ok. Is this ok, or should I start worrying about my valves?
03-15-2008, 05:29 AM
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Re: AFR's vs rpm... And timing
i have not tuned a cr but am somewhat knowledgeable in the theory. you don't do arf vs rpm because that doesn't make sence because at the same rpms you can have your throttle open a lot or a little. the map uses your pressure and the temp of that air to figure out exactly how much air is there.
03-17-2008, 12:39 AM
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Re: AFR's vs rpm... And timing
Originally Posted by confUsed
and I have 6* less timing than the most conservative map I can find. WTF?
how were you actually detecting knock?
03-17-2008, 12:10 PM
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Re: AFR's vs rpm... And timing
The tuner had some kind of electroinic detcan, dont know the brand. He has a very good name in the business here, so I trust him that he knows what a knock sounds like. But I guess I wasted my money anyway if something is off 
Could a bad tank of gas cause this? Because I dont think many people tank the higher octane stuff here in the winter, so the gas might be old or full of water from condensation...?
Could a bad tank of gas cause this? Because I dont think many people tank the higher octane stuff here in the winter, so the gas might be old or full of water from condensation...?
03-19-2008, 01:49 AM
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Re: AFR's vs rpm... And timing
mid 11's on NA pistons is where you want to be typically, 10's are too much.
buy and EGT gauge and set the timing yourself. dyno's do not come close to loading an engine like moving on the road will. If you're boarderline on a dyno, you'll be past it on the road.
buy and EGT gauge and set the timing yourself. dyno's do not come close to loading an engine like moving on the road will. If you're boarderline on a dyno, you'll be past it on the road.
03-19-2008, 02:36 AM
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Re: AFR's vs rpm... And timing
Originally Posted by Toysrme
mid 11's on NA pistons is where you want to be typically, 10's are too much.
buy and EGT gauge and set the timing yourself. dyno's do not come close to loading an engine like moving on the road will. If you're boarderline on a dyno, you'll be past it on the road.
buy and EGT gauge and set the timing yourself. dyno's do not come close to loading an engine like moving on the road will. If you're boarderline on a dyno, you'll be past it on the road.
03-19-2008, 07:05 AM
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Re: AFR's vs rpm... And timing
Originally Posted by Toysrme
mid 11's on NA pistons is where you want to be typically, 10's are too much.
buy and EGT gauge and set the timing yourself. dyno's do not come close to loading an engine like moving on the road will. If you're boarderline on a dyno, you'll be past it on the road.
buy and EGT gauge and set the timing yourself. dyno's do not come close to loading an engine like moving on the road will. If you're boarderline on a dyno, you'll be past it on the road.
03-19-2008, 10:22 AM
#9
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Re: AFR's vs rpm... And timing
Toysrme: I dont think I will be so long in constant boost on the road as I was at the dyno, so I dont know what you mean? And I doubt its hurting anything to be at low 11's/high 10's (not so sure, though). Thought you needed like 9's to start worry about bore wash? I think most subaru guys around here tune to low 10's without problems with bore wash.
Anyway, when I get time I'll double check everything, make a cheapy DIY detcan and just try it myself. Might as well start now with my stock engine. I was thinking about using a inductive clamp and try out the powerdyn software as well. http://jcdperformance.free.fr/ . Supposedly lots of people run it with very good results... I dont know (or care) about the whp part, but it looks like it can be accurate enough to compare torque graphs for tuning timing.
IDK, just need to figure out a way to tune this thing safely without having to go to the dyno every time...
Anyway, when I get time I'll double check everything, make a cheapy DIY detcan and just try it myself. Might as well start now with my stock engine. I was thinking about using a inductive clamp and try out the powerdyn software as well. http://jcdperformance.free.fr/ . Supposedly lots of people run it with very good results... I dont know (or care) about the whp part, but it looks like it can be accurate enough to compare torque graphs for tuning timing.
IDK, just need to figure out a way to tune this thing safely without having to go to the dyno every time...
