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Discussion in '1994-2004 V6 Mustang Tech' started by skatefreak, Apr 23, 2007.
That's ****ing awesome!! I thought it was just a snap on thing (easy to do).
Just a thought for those with a Windstar upper intake and also using a blower and running boost pressures. A bank to bank air flow issue will occur with the Windstar intake itself which was specifically designed for a normally aspirated motor which sucks air. By design, the Windstar intake has no way to balance air flow from one bank to the other bank because each side is not connected to the other. Thus, there is no issue with an NA motor. In a boosted motor setup however, air is being pushed (not sucked) into the motor and the shape and angle of the intake tube before the throttle body will shove more air into the driver’s side or the passenger side. More air to one side or the other creates a more lean or more rich condition on one side of the Windstar intake vs the opposite side.
The best fix would be to re-work the final intake tube that connects to the throttle body. IF the intake tube was perfectly vertical before the last bend to enter into the throttle body, the air flow would be balanced from one bank to the other. This would require making the bottom of that intake tube long enough to where the intake tube would be exactly perpendicular to the plenums of the Windstar. Think of the shape of a the letter T, with the top of the T being the Windstar intake and the bottom of the T being your intake tube. If the bottom of the T has been skewed to either the right or the left side, more air will be pushed to one side or the other. Air entry currently coming in at about 12:30 to 1:00 o’clock, or the 11:30 o'clock position will cause bank to bank air flow imbalances. Pushed air needs to be coming in at an exactly 12:00 vertical position for the air to be balanced from one bank to the other.
Data logs show this issue clearly when the short term fuel trims from one bank to another show a difference above 3 percent of each other. The differences can be as high as 10-15% or more which makes for an untunable motor. This issue only occurs in the lower half of the throttle range when the motor is NOT running in boost and the PCM in closed loop is trying to fine trim the A/F ratios for smooth running.
Interesting point of view. I'll have to look at some logs and study the o2 voltage from bank to bank.
Just look at the STFTs at any one point in the data log when the throttle counts are less than about 50%. One bank may be showing 5-10% higher than the other or conversely 5-10% lower than the other. Think about how the PCM will decide which bank to trust or trim A/F numbers. For example, bank 1 may be 1.05 Lambda and Bank 2 could easily be 0.95%. Which way would you adjust the MAF to change the A/F ratio when the wideband is showing 13.2:1?? And, by how much??
Thought of an easier fix to the Windstar upper in lieu of modifying the intake tube. Remove the Windstar intake and drill a 1/2” or better 5/8” hole in each end of the plenum runners. Get two 5/8” 90 degree brass barb fittings and epoxy the hell out of them into the Windstar intake holes. Make sure that the 90 degree elbows are facing each other. Connect the two barb fittings with a piece of hydraulic quality hose (300 psi hose) from a hydraulic hose repair shop. Clamp the rubber hose ends to the barb fittings. The imbalance of air flow will be neutralized by allowing a little amount of air to flow from one plenum (mainly the driver’s side back to the passenger side) continuously to equalize the pressure in both banks 1 and 2.
Think the fix would be under $25 and a lot less hassle than modifying an aluminum intake with multiple bends.
The dominant bank is bank 1 or bank 0 as it's written in my tune (cylinder 1,2,&3). If there is that much fluctuation between banks the ecu will disregard bank 2 o2 sensor and likely throw some codes. I think there is another issue you are having. I would look at vac leak, o2 sensor, or a bad injector. The stock mustang upper intake is very similar to the ws as each bank has it's own plenum, the mustang intake is just top entrance where the ws is fed from the front.
There is one big difference between the two uppers--The V-6 Mustang upper has a large area at the back of the intake where the incoming air does a U-turn. In this area, boosted air can equalize a balance to some degree due to its large size. On the Windstar however, the incoming air hits a wall just behind the throttle body and must do a split, the area for equalization (balance) from one side to the other is probably about only 25% of the area of the Mustang upper. If the throttle body is removed on the Windstar, one can see two tiny Vee's sticking straight out toward the throttle body which helps air decide which direction to go to. If the incoming air is entering from a straight line into the throttle body, think the incoming air would be balanced, side to side. Now, if the inlet tube was coming into the throttle body at say the 1:00 o'clock position, more air would be sent to the drivers side than the passenger side. The reverse would be true if the inlet tube were aimed at the 11:00 o'clock position where more air would be pushed toward the passenger side.
I see the picture you are painting but do not agree fully. Think of what's going on in that intake while the valves are opening and shuting. The pulsating air plays a big role in intake design also. One thing you could do is get the data to support your claim and I think the most accurate way to do this would be wire up a map sensor on each bank. I think a common and larger plenum volume is a good idea but only after a certain point. From all my data I believe the composite intake is done a little over 6000rpm due to insufficient plenum volume. I did the testing for vap some years back with a procharger and the gains I saw over the stock were pretty good.
Mine runs very well.
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