Megasquirt 6 port bridge NA help
07-31-16, 11:37 AM
#101
so i am local and will being doing my best to guide the car into a good running machine.. these guys are new to me, and i am new to them..
i was able to listen to it and poke at it on friday.. you can hold the throttle steady after a few seconds of it running at 3k rpm it goes into one rotor and and tryies to die when you open the throtle more you can hear it fire back on both of them again, and both to one as you close the throttle..
he has a bridge port, and a magnaflow muffler, i am waiting to hear if this is a chambered muffler, and i want yank it off and see if it helps.
i really think the motor should have been left stock ports if he wants to turbo it, there is no reason to bridge and turbo. now that it's bridge im going to do my best to convince him of how to maximize it as an n/a bridge, but i have a feeling once we get the exhaust bridge friendly, he won't want it at all. i blame this forum and yalls bridgeport hype for this. i don't know if he understands the motor will never cruise at a steady state. like you will be speeding up, or slowing down... always. i dont know if he would believe me if i told him. thats why i state my observations and look to you peejay, and aaron.. to back me up
it's my opinion that a bridgeport is only good when youre class says you can't peri port. and if your class says you can't turbo.. a stock motor can make well over 700hp without any porting, and probably up to 800-900 on a street port, unless you want make a drag car with 1100 hp, why on earth would you put yourself thru a bridgeport turbo nightmare is beyond me.. im looking at you aaron
or am i getting the running properties of a peri port mixed up? does or does not a bridgeport steady state cruise? dont you need wide open exhuast, no chambers?
i was able to listen to it and poke at it on friday.. you can hold the throttle steady after a few seconds of it running at 3k rpm it goes into one rotor and and tryies to die when you open the throtle more you can hear it fire back on both of them again, and both to one as you close the throttle..
he has a bridge port, and a magnaflow muffler, i am waiting to hear if this is a chambered muffler, and i want yank it off and see if it helps.
i really think the motor should have been left stock ports if he wants to turbo it, there is no reason to bridge and turbo. now that it's bridge im going to do my best to convince him of how to maximize it as an n/a bridge, but i have a feeling once we get the exhaust bridge friendly, he won't want it at all. i blame this forum and yalls bridgeport hype for this. i don't know if he understands the motor will never cruise at a steady state. like you will be speeding up, or slowing down... always. i dont know if he would believe me if i told him. thats why i state my observations and look to you peejay, and aaron.. to back me up
it's my opinion that a bridgeport is only good when youre class says you can't peri port. and if your class says you can't turbo.. a stock motor can make well over 700hp without any porting, and probably up to 800-900 on a street port, unless you want make a drag car with 1100 hp, why on earth would you put yourself thru a bridgeport turbo nightmare is beyond me.. im looking at you aaron
or am i getting the running properties of a peri port mixed up? does or does not a bridgeport steady state cruise? dont you need wide open exhuast, no chambers?
Last edited by lastphaseofthis; 07-31-16 at 12:13 PM.
08-01-16, 10:02 AM
#102
Engine, Not Motor
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Now all that said, I invite you to try a few bridgeport cars I have tuned that cruise happily all day long at 2K RPM with only the slightest pulsation detectable, idle at 14:1 non-stinky, creep in traffic by letting the clutch out at idle, and run down the highway at leaner than 16:1 getting actual reasonable fuel economy (though not in the city).
That said again, the bridgeport is the most difficult port to tune for a number of reasons. Not the least of which is a very ambiguous vacuum signal compared to ports with less overlap that tends to overlap multiple operating points and behaves somewhat like a sine wave in cases. Cause the vacuum is terrible at low RPM due to the overlap but even with linear application of throttle starts to increase at high RPM. Plus the overlap creates so much intake pollution that there is a fine line between getting a stable idle, being too lean, and just tossing fuel out of the tail pipe. Not to mention the amount of fuel needed at low RPM. That's an odd one as well, that the engine consumes more fuel at idle than at cruise so the non linear fuel map takes some getting used to. Peripheral ports tend to pollute the intake charge far less than high overlap side ports and have a more manageable vacuum signal. Behaving somewhat more like a side port with less vacuum that goes away much quicker. Oh, that's another thing. There is very little room on the bridgeport between full vacuum and no vacuum, unlike a side port that is at least mostly linear.
Unfortunately it's just the worst port to learn EFI tuning on. We haven't got into timing yet but bridgeports love it. Lots of timing at idle, bring in a lot of advance mid range for cruise then end up in the high 30s under WOT at high RPM.
Of course there are some advantages to the bridgeport. Mostly the fun factor. One thing a bridgeport does is really make the car raw. One feels the engine, it makes all the noises, and of course just keeps making power at the high RPM when all side ports tend to fall off.
In the turbo realm, the overlap really helps spool large turbos quicker than stock ports can hope of. But with modern turbos, that's less of an advantage coupled with the disadvantages of the bridgeport (fuel economy being the big one). Turbo bridgeports are actually rather quiet. The turbo is a very convenient muffler.
Now back to the problem of the thread. I can't think of mechanism that would make the car run on one rotor after a few seconds of being held at 3K. A datalog would REALLY help. But, it can really sound like a bridgeport is running on one rotor if it's just too lean. Which is possible. Engine gets revved up to 3K, that area of the map is lean, the transition fuel runes out and the engine moves into a lean bin then starts misfiring. Could be very confusing for the first time tuner as bridgeport will consume less fuel at 3K unloaded than at idle!
That said again, the bridgeport is the most difficult port to tune for a number of reasons. Not the least of which is a very ambiguous vacuum signal compared to ports with less overlap that tends to overlap multiple operating points and behaves somewhat like a sine wave in cases. Cause the vacuum is terrible at low RPM due to the overlap but even with linear application of throttle starts to increase at high RPM. Plus the overlap creates so much intake pollution that there is a fine line between getting a stable idle, being too lean, and just tossing fuel out of the tail pipe. Not to mention the amount of fuel needed at low RPM. That's an odd one as well, that the engine consumes more fuel at idle than at cruise so the non linear fuel map takes some getting used to. Peripheral ports tend to pollute the intake charge far less than high overlap side ports and have a more manageable vacuum signal. Behaving somewhat more like a side port with less vacuum that goes away much quicker. Oh, that's another thing. There is very little room on the bridgeport between full vacuum and no vacuum, unlike a side port that is at least mostly linear.
Unfortunately it's just the worst port to learn EFI tuning on. We haven't got into timing yet but bridgeports love it. Lots of timing at idle, bring in a lot of advance mid range for cruise then end up in the high 30s under WOT at high RPM.
Of course there are some advantages to the bridgeport. Mostly the fun factor. One thing a bridgeport does is really make the car raw. One feels the engine, it makes all the noises, and of course just keeps making power at the high RPM when all side ports tend to fall off.
In the turbo realm, the overlap really helps spool large turbos quicker than stock ports can hope of. But with modern turbos, that's less of an advantage coupled with the disadvantages of the bridgeport (fuel economy being the big one). Turbo bridgeports are actually rather quiet. The turbo is a very convenient muffler.
Now back to the problem of the thread. I can't think of mechanism that would make the car run on one rotor after a few seconds of being held at 3K. A datalog would REALLY help. But, it can really sound like a bridgeport is running on one rotor if it's just too lean. Which is possible. Engine gets revved up to 3K, that area of the map is lean, the transition fuel runes out and the engine moves into a lean bin then starts misfiring. Could be very confusing for the first time tuner as bridgeport will consume less fuel at 3K unloaded than at idle!
08-01-16, 11:40 AM
#104
Old [Sch|F]ool
Now all that said, I invite you to try a few bridgeport cars I have tuned that cruise happily all day long at 2K RPM with only the slightest pulsation detectable, idle at 14:1 non-stinky, creep in traffic by letting the clutch out at idle, and run down the highway at leaner than 16:1 getting actual reasonable fuel economy (though not in the city).
Now back to the problem of the thread. I can't think of mechanism that would make the car run on one rotor after a few seconds of being held at 3K. A datalog would REALLY help. But, it can really sound like a bridgeport is running on one rotor if it's just too lean. Which is possible. Engine gets revved up to 3K, that area of the map is lean, the transition fuel runes out and the engine moves into a lean bin then starts misfiring. Could be very confusing for the first time tuner as bridgeport will consume less fuel at 3K unloaded than at idle!
Another thing I have long noticed is that TRAILING ignition is critical with a high overlap engine at low load. It can run great at WOT on leading only but barely run at all at idle or cruise. A bad trailing plug/wire or distributor cap (if present) can really throw a monkeywrench into tuning. Ideally all of these parts will be "proven good used parts" but this is not always possible.
08-03-16, 11:29 AM
#105
Ratchet_Brap
Thread Starter
Update: I played with the fuel map and ignition map some and now I have the car not missing at idle and pulling somewhat smooth, (it's not fast by any means but im getting the Fuel map sorted out) fuel map was dumping fuel, (back from me being stupid and not realizing I had a bad fuel pump so I tried to up the fuel map to see if AFRs changed) it still dies during deceleration at times but it's getting there, I just have a little bit more cleaning up to do on the map and then I have to find a place to get some dyno time, my buddy Austin has been giving me lots of knowledge and has been tinkering with the maps as well, I am just a little hesitant to street tune it because I fear the car stalling out and me being stranded 3-4 blocks away (which doesn't sound like much but is a hell of a push when it's 106° heat index in the Ohio valley haha
08-06-16, 10:26 AM
#106
Engine, Not Motor
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Glad to hear it! If the map is truly messed up, then you can re-import the VE table from my website to give you a starting point that is smooth (just really rich). If you can, just lapping the block with autotune turned on for the cruise regions will make a big difference. Most of the tuning you can do on the street to avoid costly dyno time. In fact, assuming you can stay within local laws (or have an area which can become a SAFE "test track") you can do almost all of your tuning including the WOT runs with the dyno only needed to finalise things.
08-09-16, 12:36 PM
#107
Ratchet_Brap
Thread Starter
My buddy and I are going back at it on Sunday, I'll keep you in the loop! I'll look at me VE table and see if it's butchered or not, if so I'll hit your website up, send me good vibes fellow Ro-Tards, I'm gna need it hana
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