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Discussion Starter #1
I know guys have argued about different systems controlling coil activity and which system can control a smart coil at 200+hp per cylinder. My question is regarding the wiring itself. Say for instance, a car like my own. It makes 60+ psi boost, 393ci, 11:1 compression with an AFR between 2.8-3.0AFR. We run a gap of .016" and dwell in the vicinity of 7Ms. My current wiring is a 10 AWG from battery split with 10awg to two 40 amp relays, into the 4 power wires for the coil on the holley harness which appears to be 20 awg at each coil. The head grounds are wires the same way with a 10 AWG to each head. There was talks recently about wiring being too small, and current draw being 20-30amps or more on each bank with 5 ms dwell on other combos, so you would figure mine would consume more current being 7ms) ? I had some time on my hands and opened the relays to see if there was any signs of heat, and they look brand new. As do the pins on the coils and the pins on the connectors. My reason for checking all this is a small surging miss that i have noticed down track and am ruling things out one at a time. We haven't yet tested again this year, but it has 100 more psi valvespring pressure now, and a few other things to rule out mechanical possibilities. We are going to also try using a tighter gap to see if it promotes completed spark better. I look to upgrade to a cdi deal at some point but for now, i would like to see if this will get the job done. Am i wasting my time on overthinking my wiring? is there any signs that could elude to the wiring not being good enough? not trying to start a pissing match between companies here, just wouldnt mind some electrical input?
 

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Discussion Starter #3
I sure seems less apparent around 50-55psi vs 60
 

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Hey Nick,
Tightening up the gap is a good idea. I know a guy here in NC that went 186mph 1/8th mile with a MSD-7531 box with .011" plug gap. If he would have asked 100 people if it would work probably 100 people would have said no including me, LOL. Definitely better ways to accomplish this. Just a FYI, M&W now has a 1000mJ CDI ignition that is similar in operation to the FT or Holley in that it can be run at lower output for continuous duty or at full output for short duration applications like drag racing. Not saying its necessary but it can definitely compete with a 44 amp Pro Mag. None of them can maintain spark output for 26* of crank rotation like the mag can. I'm assuming you are already on a 16V battery?? Have you logged coil input voltage during a run??
 

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Discussion Starter #6
We do run a 16v battery and no i havent had a chance to check my input voltage yet, although this season i am logging it. Havent had a chance to test yet because of this stupid corona crap. The holley does a voltage based compensation for the dwell so its actually around 6.2MS corrected when this is all happening. Im definetly gonna try the spark plugs tighter as well. I also switched from the 4 magnet to 12 magnet crank sensor deal which may not do anything for us, but its in there now, and people seem to think its a better route. I wish i could lean it out a bit more but this chamber isnt softened and its bordering 3/4 a ring if i get after the AFR a bit, with little to no change in performance. I like the misfire log stuff and internal can stuff with the MSD system, and was going to wait to see a few other cars run it before i spent the $$ on it, but if it still does this, im gonna likely bite the bullet and put something on it.
 

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Discussion Starter #9
It does have a much hashier RPM signal when this is occurring. The AFR goes hashy pretty good when this is happening as well. I have set up log channels from my 5v source voltage and 12v source to log as well. Just haven’t had a chance to make any hits as I grenaded my converter in Vegas SCSN on the stands before my first run and haven’t had a track open nearby to test :( hoping after a few test hits I can get to the bottom of it. It’s gone 4.05 181mph with the problem present from .5 seconds onward and I can’t help but think just making it smooth out would be worth some ET, hopefully enough to get the elusive 3 second pass...
 

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Are you showing any noise on the data logs ?
I ran into this issue two years ago as well. Beginning of the spring the car started too surge as all the boost and load came in. We traced it to two things. When the car came apart over the winter, all the wiring, and boost control reference lines, did not go back into the same places as the year before (where the car ran without issue) and as well, we added a driveshaft sensor, and the harness that was built was creating a lot of noise from that sensor, and effecting how everything else felt. It showed up especially clear in the rpm stream, and the 02 stream on the datalogs, as well as the waste gate pressure stream. I am no where near the power levels you're at, but to me, noise is noise.
 

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Discussion Starter #12
I have a set of both MSD and Magnecore 10mm wires. Both are less than 10” long as coils are mounted on double frame rail under headers.... we run a -11 NGK 6596 plug. I’ll admit I have never taken the dwell that high. Worth a shot regardless, especially if I am not seeing any negative side effects in any of the wiring.
 

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Discussion Starter #13
As far as electrical EMI noise, i would like to believe I have done everything possible to prevent any. I run Hall effect crank and cam sensors as well as shielded cable on every single sensor and input. It has the shield drains going to the ecu filtered ground for every input to the ecu. Injectors are wired with 70 amp 10awg direct to the battery as are the coils. Ground from block/heads direct to battery with 0awg and nothing is chassis grounded. Everything is battery grounded basically. I had lots of RFI issues with my fast XFI that I had to remove because nobody could get to the bottom of it. I took every single possible measure to make sure no electrical noise could come from it lol.... even my transbrake and bump inputs are 2 wire shielded...
 

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I have a set of both MSD and Magnecore 10mm wires. Both are less than 10” long as coils are mounted on double frame rail under headers.... we run a -11 NGK 6596 plug. I’ll admit I have never taken the dwell that high. Worth a shot regardless, especially if I am not seeing any negative side effects in any of the wiring.
I would use the magnecore, they are 30x better than MSD, I use firecore on everything now with no issues, I use the r5671a-10, never tried the 11, never had anything that needed a plug that cold,
I doubt it is a RFI issue you would see that in the data logs
 

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Arent you suppose to use resistor plugs with efi? I have read you dont but when i ran the typical ngk race plugs everyone runs i had a weird blip at 5500 rpm, you can hear and feel a hesitation that did not seem to be fuel related. I put in resistor plugs and it went away
 

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Discussion Starter #16
I don’t know of a resistor plug in the #11 heat range that we use? I haven’t seen anyone really using a resistor plug at this boost/power level? fortunately being coil near plug, EMI is far less troublesome. We remove the cap and rotor from the equation and shorten the plug wires a TON. The coils were also mounted specifically below all the main efi wiring to avoid any chance of EMI as well. My magnecor wires are specific EFI wires made for EMI resistance and were spec’d to be by Fast when I had EMI issues in my mustang. Any other wire would make my mustang shut off on its own randomly. They must do a better job lol. The next two steps in my equation would be a tighter gap and stepping the dwell up slightly to see if it helps. I still can’t rule out valve springs, and a couple other small things until we test again.
 

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Discussion Starter #18
Yeah, we came up with a better valve lock combo that got us a closer to optimal coil bind distance at full lift, and equates to about another 100 over nose psi as well. Springs all tested better than rated. Better than the new set i have sitting here to replace them when needed. We had a few issues with some valves that were heavier than the average by 10% and have since changed those as well... If a track would open up so i could test this thing, it would sure rule out the things i HAVE done in an effort to remedy it. Probably about a month out at least with how this virus crap is going :(
 

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Discussion Starter #20
Roughly 320 seat, 780 over nose. 8mm valve, with .660 lift with the 1.6 rockers we run. Last season we were about 260 on the seat and about 700 ish over the nose. WIth the 8mm valve we are a bit gun-shy about putting much more spring pressure on it. Especially with standard 7/16" stud mount rockers and 5/16 pushrods (albeit thick wall). Valves weight roughly 115 grams +- 1 gram
 
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