Manual A/F manipulation

[SicSE]

Before all the haters come out of the woodwork, I want everyone to know that this was experimental and happened by chance.

I ran the SE on the dyno today and got this;

I have reinstalled a CAT, and changed intakes & PCV configuration since my 200/201 run, so I expected some losses, but this was a bit much. Thankfully, I also redid my air inlet today to run a different MAF, (not the newest card styles, but the plastic style before that, which was used in multiple platforms from about 02-04), inserted into a 3" CAI, (more on that another time), which gave me that horrific A/F curve... and where I figured most of my losses came from. I just couldn't leave it that way. So after much trial & error reshaping the MAF, and about 14 runs later, I ended up with this;

I'm sure I'll get sh*t for the way I got there, but I'm pretty damn proud of that resulting A/F curve.

 

[gorman]

interesting ... you didn't seem to get any benefit while the A/F was over stoic... but once you dropped below it , you seemed to gain some power for maintaining a higher A/F. Serendipity ... a win is a win .. congrats. All these A/F traces seem to be proportional and linear in the way they fall off. I wonder if it is possible to jerry rig the regulator to close the fuel return more as the rev's climb ... a sort of exponential curve not a linear one ....G.

 

[cichlidbob]

I am not sure what A/F these motors like but seems that you are a bit rich for NA application. My NA Cobra liked 12.5:1 A/F but was also a heavier vehicle. My FI Cobra likes 11.5:1 A/F but is much heavier and has boost and nitrous.

I would be willing to bet there is some power to be had under the curve with added timing and adjusting your maf transfer functiona nd fule tables to reflect 13:1 - 13:5 A/F ratio.

Nice numbers for a Contour... I bet that 3L feels peppy.

 

[SicSE]

If I could figure out a way to lean it out a bit more, but only at 5k+, I would definitely try it. But the changes that I made pretty much just moved the whole curve up or down and I don't think I want to move it any higher for now.

 

[cichlidbob]

I use the SCT PRP software on my Cobra. It can be pricy, however, I learned a lot by tuning my own vehicles. It actually saved me money becasue I do not have the urge to buy bolt-ons. I have the urge to improve on my tune and make minor adjustments as the mood strikes me. I have been contimplating on buying the database for the Contour. I do not plan to add or mod the motor so no need for my application. Only way I will get a 3L is if I buy a swap that has been completed. I am not changing a motor int this car again...f$%& that.

 

[striker2]

you need a proper tune so you can richin it up to about 13:1 below about 4700 and then lean it out above that, again to around 13:1. you should see some gains across the board by doing that.

 

[biminiLX]

How are you measuring the A/F? tailpipe or exhaust bung?
-J

 

[SicSE]

you need a proper tune so you can richin it up to about 13:1 below about 4700 and then lean it out above that, again to around 13:1.

Yeah, I could definitely stand to gain a bit with a tune. But, I have more faith in the factory programming than any tuner, (other than maybe Jerry - the guy that started SCT, but only because he used to do factory programming!). No offense intended to any tuners that may read this... that's just me. In other words, a tune is still pretty low on my list of priorities.

How are you measuring the A/F?

Tailpipe. I've been wanting to do a comparison between the two different spots, especially since I AM running a CAT, but just haven't gotten around to it yet. Have you seen a comparison & how much of a different reading you get from one way to the other?

 

[biminiLX]

Tailpipe. I've been wanting to do a comparison between the two different spots, especially since I AM running a CAT, but just haven't gotten around to it yet. Have you seen a comparison & how much of a different reading you get from one way to the other?

Very good tuners that do my cars and those I trust all favor an 02 bund welded into the exhaust to use a WB there.
Not saying the tailpipe is bad, just not as good.
However, if you look at track results vs. dyno numbers at various A/Fs, I've found alot of Mustang guys go faster at the track (make more power) by adding fuel over what proved best on the dyno.
Use the dyno to get it close and then add/subtract fuel at the track and compare the trap speed.
-J

 

[KAOS_3.0]

interesting ... you didn't seem to get any benefit while the A/F was over stoic... but once you dropped below it , you seemed to gain some power for maintaining a higher A/F. Serendipity ... a win is a win .. congrats. All these A/F traces seem to be proportional and linear in the way they fall off. I wonder if it is possible to jerry rig the regulator to close the fuel return more as the rev's climb ... a sort of exponential curve not a linear one ....G.

this is going to get a lot of hate, but you can use a socket to "squish" the FPR down to get richer. it's a jack leg trick the turbo 2.3 guys use

 

[gorman]

this is going to get a lot of hate, but you can use a socket to "squish" the FPR down to get richer. it's a jack leg trick the turbo 2.3 guys use

thanks for the tip... but my FPR has plenty of adjustment on it. What i really need is some discussion on tuning strategies... like, what would a perfect A/F trace look like ? ... G.

 

[SicSE]

like, what would a perfect A/F trace look like?

That is going to depend on your individual setup and goals... and even then you may get differences of opinion as to what is "perfect". Most tuners I've talked to, or heard discussing the issue, like to flatten the A/F curve, and keep it leaner than 13:1 NA, and richer than 13:1 in boosted applications... as a generalization. Spark timing, compression ratio and fuel octane all affect a good tuner's desired A/F ratio for a given platform. If you're looking for max power, the numbers would typically be leaner, but it gets to a point where going leaner yields only a tiny amount of additional power at the expense of greatly increasing the chances of detonation.

 

[gorman]

That is going to depend on your individual setup and goals... and even then you may get differences of opinion as to what is "perfect". Most tuners I've talked to, or heard discussing the issue, like to flatten the A/F curve, and keep it leaner than 13:1 NA, and richer than 13:1 in boosted applications... as a generalization. Spark timing, compression ratio and fuel octane all affect a good tuner's desired A/F ratio for a given platform. If you're looking for max power, the numbers would typically be leaner, but it gets to a point where going leaner yields only a tiny amount of additional power at the expense of greatly increasing the chances of detonation.

Thanks SicSE; low pressure FI is my goal... so i need sufficient fuel flow to maintain 13:1 A/F all the way to 270fwhp... G.

 

[striker2]

Thanks SicSE; low pressure FI is my goal... so i need sufficient fuel flow to maintain 13:1 A/F all the way to 270fwhp... G.

If your going FI then you want to shoot for 12:1

 

[biminiLX]

Need to clarify FI as forced induction (boost) or fuel injection.

thanks for the tip... but my FPR has plenty of adjustment on it. What i really need is some discussion on tuning strategies... like, what would a perfect A/F trace look like ? ... G.

No real perfect A/F as SicSE mentioned.
Also, reread this:

However, if you look at track results vs. dyno numbers at various A/Fs, I've found alot of Mustang guys go faster at the track (make more power) by adding fuel over what proved best on the dyno.
Use the dyno to get it close and then add/subtract fuel at the track and compare the trap speed.
-J

So, just because it makes the best power on the dyno, doesn't make it the the best A/F.
-J

 

[gorman]

Also, reread this:

So, just because it makes the best power on the dyno, doesn't make it the the best A/F.
-J

this i read earlier and thought.. my cold air feeds work better at speed... if i was having a remap done on a dyno, i would not be getting the air i would get at speed, so i understand why the mustang guys get different results when stationary with a fan and running at speed. I haven't seen under a mustang race car hood ... but i bet they have proper cold air intakes like WRC cars do .. G.