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I'm in the process of building a 402/403 myself and was curious how the s400 turbos work with them cubes. I have a bullseye billet s483/96 1.32 and was getting nervous that it was going to choke it out but seems like your still making it work!
Im using a 5.7 with 317 heads... is the Sniper intake made by Holley? Im already using Holley fuel rails with Racetronics 160lbs injectors. Think I would gain anything over the LS6 intake?
The AUS injectors are working fine and are a nice alternative to the over-priced IDs. Should work even better when I finish sorting out the charging issue.
Sniper is a brand name that Holley puts on their version of the chinese made intakes. Unless you have a big cam and looking for big HP in the upper RPM range, I would stick with the LS6 intake. Just look at what Mark Frederick did with a LS1 intake. I seriously considered a stock LS3 intake, but sorting out the fuel rail/brackets, TB and cable bracket, it was just a tad less than the sniper setup and didn't have the "the look"
I built mine for dyno bragging rights and a highway roller... I'm using twin 61mm turbos and a Comp Cam Intake 227 @50 lift 624, Exhaust 235 @50 lift 610 Lobe Separation 115. And i love the "look" but I'll have to cut my hood which would still look cool haha
I think I've found the problem but haven't gone out yet to test it. I'll test it tomorrow then hit the track Wednesday.
I put a wire on the alt batt terminal and ran into the car to my volt meter so I could see what the alt was putting out at WOT and compare it to the DL. I got into it in 2nd at 4,000 and did the 2-3 at 7,000 and the alt held steady at 13.85V. The DL showed the batt had 13.8V at 4,000 then once I went 100% TPS, it steadily dropped, flat-lined at 12.7V and came right back up soon as I got off throttle. I then moved the wire from the alt batt terminal to the batt itself and the batt held steady at 13.7V at WOT. I could have continued moving the volt meter around but it hit me at what the problem was.
I had the coil 12V and GND coming from the ECU harness and the coils were demanding more voltage than the ECU could provide. Willing to bet if I continued testing with the volt meter I would have seen normal voltage for everything that the ECU was not providing power for. I opened up the coil sub harnesses, separated the 12V wire and provided 12V from a relay for each bank. I also separated the GNDs and connected them to the head just below the big connector on each bank. Now the ECU only has to provide 12V for the injs and the coils and injs should be much happier.
Now when I rap the throttle up to 5,000 (in Park), the engine note has a sharper bark, so I am hopeful. Since I run full sequential, only 1 coil is firing at a time, but these IGN-1As are jokingly called arc-welders. I have a dwell compensation table set up, so it helped compensate for the low-voltage. I would also strongly recommend this mod for anyone trying to make big HP, especially FI, using the D585s.
I will post results after I test tomorrow or at the track Wednesday.
What MS3 harness are you using? I was looking at mine today after reading this. The injectors and coils have a dedicated 30a relay on the EFI Source harness with a 15a fuse. Firing sequentially I cant see the coils and injs needing more than that? Or was your harness not wired this way?
I'll check mine with a meter as u did. Sounds like it was obviously beneficial in your case. Hope mines the same way!
I had annoying voltage drop issues last year, but the 160a alt seems to have fixed it for the most part. Volts still drop to 13.2 or so from 14.4 on both my cars. Also when the fan kicks on the AFR leans out.
It's wired that way. However, the wire supplying 12V to the coils looks like 20g, 18g at best, that splits for the 2 banks and about 8' in length by the time it gets to the big connectors and another 1' or so to get to the coils. They look like the same gauge wires used for 0-5V sensors and these coils can draw as much as 19A. Even 13.2V is not enough when you're trying to push 800-1000hp. From my injector data (DC% and flow) I estimate my 133.2# injs are flowing about 124.8# so I know the coils are not firing as hot as they are suppose to. Willing to bet your voltage drop is like mine, starts dropping as the load increases and immediately comes back up when you get out of it. The voltage being reported by the ECU is measured in the ECU no matter what it is at the battery or any other part of the car outside the ECU.
I built mine for dyno bragging rights and a highway roller... I'm using twin 61mm turbos and a Comp Cam Intake 227 @50 lift 624, Exhaust 235 @50 lift 610 Lobe Separation 115. And i love the "look" but I'll have to cut my hood which would still look cool haha
Which turbos are you using exactly? Have any results for them?
I think I've found the problem but haven't gone out yet to test it. I'll test it tomorrow then hit the track Wednesday.
I put a wire on the alt batt terminal and ran into the car to my volt meter so I could see what the alt was putting out at WOT and compare it to the DL. I got into it in 2nd at 4,000 and did the 2-3 at 7,000 and the alt held steady at 13.85V. The DL showed the batt had 13.8V at 4,000 then once I went 100% TPS, it steadily dropped, flat-lined at 12.7V and came right back up soon as I got off throttle. I then moved the wire from the alt batt terminal to the batt itself and the batt held steady at 13.7V at WOT. I could have continued moving the volt meter around but it hit me at what the problem was.
I had the coil 12V and GND coming from the ECU harness and the coils were demanding more voltage than the ECU could provide. Willing to bet if I continued testing with the volt meter I would have seen normal voltage for everything that the ECU was not providing power for. I opened up the coil sub harnesses, separated the 12V wire and provided 12V from a relay for each bank. I also separated the GNDs and connected them to the head just below the big connector on each bank. Now the ECU only has to provide 12V for the injs and the coils and injs should be much happier.
Now when I rap the throttle up to 5,000 (in Park), the engine note has a sharper bark, so I am hopeful. Since I run full sequential, only 1 coil is firing at a time, but these IGN-1As are jokingly called arc-welders. I have a dwell compensation table set up, so it helped compensate for the low-voltage. I would also strongly recommend this mod for anyone trying to make big HP, especially FI, using the D585s.
I will post results after I test tomorrow or at the track Wednesday.
Pretty interesting. I did run a 10awg wire to each head and tied them to the coils, but maybe the issue is the ~16 awg that is part of the coil harness?
It's wired that way. However, the wire supplying 12V to the coils looks like 20g, 18g at best, that splits for the 2 banks and about 8' in length by the time it gets to the big connectors and another 1' or so to get to the coils. They look like the same gauge wires used for 0-5V sensors and these coils can draw as much as 19A. Even 13.2V is not enough when you're trying to push 800-1000hp. From my injector data (DC% and flow) I estimate my 133.2# injs are flowing about 124.8# so I know the coils are not firing as hot as they are suppose to. Willing to bet your voltage drop is like mine, starts dropping as the load increases and immediately comes back up when you get out of it. The voltage being reported by the ECU is measured in the ECU no matter what it is at the battery or any other part of the car outside the ECU.
Well, it's a theory and hope to test it soon.
Gotcha, good point. I hope that’s it! Relatively easy fix and worthwhile “upgrade” anyway it sounds like.
Originally Posted by 69-chvl
Pretty interesting. I did run a 10awg wire to each head and tied them to the coils, but maybe the issue is the ~16 awg that is part of the coil harness?
Might tap the power supply at one coil with your meter and go make a pull. Let us know what you find? I was going to try this weekend but the weather was nasty. The IGN-1As are on another level, I can’t imagine the foot or less of 18g wouldn’t be enough to power a D585 sequentially if you have 10g to each INJ harness? Defiantly a worthwhile test though! Would be funny if that solved the Holley coil issues so many folks have.
I also had voltage issues at the beginning of last summer.... I thought it was the old fuse box letting me down in my 68 Camaro.... I relocated the battery to the trunk and did not use heavy enough battery cable to the starter.... and also didn’t use heavy enough wire to alternator..... ended up using 2/0 from battery to starter, 2/0 for ground from battery to engine, 2/0 from battery to frame, and 2awg from battery shut off switch to alternator.... if you google wire sizing chart it will tell you what wire to use according to how many feet the run will be.... hope this helps some
Gotcha, good point. I hope that’s it! Relatively easy fix and worthwhile “upgrade” anyway it sounds like.
Might tap the power supply at one coil with your meter and go make a pull. Let us know what you find? I was going to try this weekend but the weather was nasty. The IGN-1As are on another level, I can’t imagine the foot or less of 18g wouldn’t be enough to power a D585 sequentially if you have 10g to each INJ harness? Defiantly a worthwhile test though! Would be funny if that solved the Holley coil issues so many folks have.
I should clarify - I pulled a 10g GRD wire to each cyl head and tied it to chassis grd. I forgot to tighten adequately the 16 or 18g grd Holley harnss grd wire to the head and ended up bending all the rods on that bank! It showed me how important grounding was to the coils. But I'm also losing system voltage like the OP's was as measured by the ECU which connected to the to the battery. Wondering if the low-imped injectors pull that much more? Be nice to get an ammeter installed to see what those coils or injectors are pulling. Might be more than we think!
Well, I did the test and apologize beforehand if I ramble
Even though the car ran a 8.629 last week, it now feels like it has been transformed! I included the DL and the focus will mainly be on the vertical line and the values at the far right. In the top display frame you can see I'm at 6919 RPMs with 12.1psi and 16.5* and the middle frame is all related to fueling. However, we are mainly interested in the bottom frame that shows Batt V at 13.4V. For me, that is an increase of .9V at WOT from the 8.629 pass. Since the voltage being reported by the ECU is measured in the ECU, it's evident that moving the coil 12V/GND made a difference in what the ECU is seeing. As for the voltage at the coils, I don't know, but based on the seat of pants.......
So what was my butt feeling? I picked that point in time to put the vertical line for a reason. I had to pedal and shift because the car was going sideways. RPMs dropped from 7050 to 4855, and boost down to -1.3. Got back in it and it started spinning immediately and I noticed in the DL that the boost came back from -1.3 to 12psi as fast as I could go back to 100%TPS. Never seen it spool back up that fast. Also, at 12psi the DL said the injectors were flowing 675lbs of E70 and with a BSFC of .75, that factors out to 900 fwhp. My converter slip thru the traps was about 3.6%, so make of that what you will.
That's all water cooler talk and we'll see how it does at the track. I am curious to see what the voltage is at the coils but will wait until after track.
Couple of things to finish up. My coil rewiring is total overkill but seems to be working. Making the ECU harness wires a heavier gauge probably won't do anything because I'm pretty sure the 12V circuit on the motherboard is designed to handle less than the max amperage 8+' of whatever gauge wire it is using.
02-02-2018, 08:18 PM
and these coils can draw as much as 19A. Even 13.2V is not enough when you're trying to push 800-1000hp. From my injector data (DC% and flow) I estimate my 133.2# injs are flowing about 124.8# so I know the coils are not firing as hot as they are suppose to. Willing to bet your voltage drop is like mine, starts dropping as the load increases and immediately comes back up when you get out of it. The voltage being reported by the ECU is measured in the ECU no matter what it is at the battery or any other part of the car outside the ECU.
