Timing question

[Calypso5.0]

Hi All;
I have a 60,000 mile 1993 Calypso 5.0 and a few questions. This car was bone stock until I recently added BBK headers, Mac X pipe (no cats), Mac mufflers/dual and Mac cold air intake. The Mustang ran extremely well for about a month until I recently noticed hesitation and backfire from the exhaust under load...also may have been using more gas. My first assumption was that I was running rich and had been gradually fouling the spark plugs. Additionally, I am pretty sure the wires/cap/rotor are original or OEM so planned on replacing them to eliminate that as a source. I picked up a nice set of 8mm wires, a good cap/rotor and installed. I pulled all plugs and was surprised to find they appear to be running lean - light in color. I gapped all new plugs at .054" and installed cap/rotor/wires. As I had lent my light to my brother, I just started timing out by feel and rotated just slightly clockwise...with better performance results - no backfire, etc. But having changed several variables I am not sure this was the "fix". I typically run 91 octane but in a state that has high use of ethanol so also questioned if that could have impact. Question #1 - does the lean condition make sense given the mods? #2 - is advance clockwise or retard? #3 - Ethanol impact seen by anyone?
Mustang ran great for the first few weeks after exhaust/cold air - no warning lights, etc. Any input appreciated!
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[Vipersix]

Hmm... very intriguing!

So you said that you had no warning lights during the first few weeks but you never mentioned if you eventually got one. Did you? Pull any codes?

Nothing really jumps out at me as a culprit for all this madness. One thing to consider is the lack of cats. Most computers do not like it when you pull the cats away from them and no longer have a signal to bounce off when determining fuel quantities, timing numbers, and all of the other magical things a computer does. Did you simply leave the harnesses dangling or did you hook them up to one of those swoopy cat removal tricksters which send a stoich reading back to the computer? Honestly though, I'm not sure why everyone seems to want to remove the cats all the time. They're not worth the hassle of removal as far as I'm concerned.

Anyway, in an attempt to answer your questions, lean doesn't really mean anything based off the modifications you have listed. Theoretically, opening up your exhaust and your intake ever so slightly would imply you are getting more air volume and therefore should experience a lean condition. However, the lack of cats now gives the computer no way of determining if it is dumping the correct amount of fuel into the motor. Based off MAF readings (assuming a slightly larger volume) the computer should be dumping more fuel in, not the same or less, and therefore should be seeing a rich condition. But there is no way of knowing what the computer is doing.

Second, based entirely from memory, clockwise rotation of the dizzy is advance.

Finally, I have seen plenty of ethanol impacts (though some people like to claim that I just hate ethanol or am crazy or any other excuse). South Dakota has used an ethanol blend in their gasoline for a good ten years if not longer. As such, we have had plenty of time to see the slowly built side-effects of ethanol usage. Obviously the vehicles were not designed to use ethanol back then so this may have something to do with it. The most damaging aspect to the motor I have seen is corrosion and erosion of the valves. For some unknown reason it likes to eat through the valve seats and wreak all sorts of havoc on the heads. Most distinguishable to the driver is the dislike for cold weather. The distributors have reduced the ethanol content in the winter over the past few years to offset this.

That said, ethanol has great potential as a performance fuel provided that a person is not ignorant of the increased volume demanded and changes in timing/ignition needed.

 

[Calypso5.0]

Vipersix;
Thanks for response and feedback...The Mac X pipe has ports to reinstall O2 sensors and I did reinstall accordingly. The X pipe also has port for stock smog pump and I maintained functionality with all that equipment also. Correct I did not have any warning lights at any time - and still have not gotten any...so no codes to decipher. Again to clarify - the 93 Mustang only has 02 sensors before the cats - none after (94 does?) As far as why I removed them...my consideration was based on restriction, sound and the fact I do not have testing in my state.
The car is driven about 1000 miles a year and is currently running good...I plan to set proper timing tonight and see where I am - my assumption is to target 12/13? Based on research this is a good range. I do run 91/93 octane here (currently just over $2.00/gal!) and hoping to put it behind me before I store the car in the next few weeks.
Thanks again for insight and feedback!

 

[Vipersix]

I just assumed that you did not reinstall the O2 sensors. Most people I know who remove their cats also remove the sensors so I just assumed you did as well. Assuming the correct sensor operation and no codes then... You've got yourself an interesting scenario! I'm not sure why you would be running rough as you had experienced with only those changes. Seems rather counter-intuitive!

Get a good tune on it and I'm sure you'll be just fine. It's always a good idea to re-tune after any parts change anyhow.

 

[Calypso5.0]

Timing

Just got timing dialed in at 14 - still seems to be lacking in top end power compared to when I first installed mods. Don't want to go much higher due to detonation potential - but did seem to run stronger when I set it by ear and was calibrated at around 17...have been running 93 octane and had recently added octane boost also. Too much octane for application??? Runs fine but once had a taste of the top end power, is hard to go back.
Have a new set of rims coming this week so will put them on and tuck it away for the winter...
Thanks for the input!