s55 coils in an n54?
- Thread starter tisdrew
- Start date
I tapped this thread to see if more feedback exists (and seems to occur both over time and as new people join.)
I don't don't doubt the PR solution (and BL) is a more powerful solution, and more resilient to tuning for lack of a better way of saying it. I trust @V8bait on this - he's done the heavy lifting on that aspect.
I tickled this thread because from what I have seen, both of these solutions are better run by people that have a DIY clue or are closely attached to a highly skilled mechanic (I say highly skilled because your average import shop that does competent changes on motor mounts, plugs, and shocks is insufficient). I get people asking me questions about their setup who, in my opinion, are better off sticking with "stock" solutions from an end-user perspective. They are also people doing FBO-ish kind of things (sub 500whp). Such folks are not in the position to gauge how well these installs are performed - either by doing it directly or by assessing their installer's chops. In other words, IMHO, trying to keep ownership complexity down while they still do some FBO modding. Hence the question.
Filippo
Last edited:
Hi, OP here. So I finally logged in to see all these notifications
So I actually went through a few stages here:
OE coils from the factory These had approximately 65k miles on them when I replaced them, had two go bad and has some misfire issues while completely stock and on a mix of injectors (1,2,4,9).
OEM replacement bosch coils
These worked fine from totally stock, FBO+e60+custom 24psi tune @ 455whp and even once I upgraded to MMP turbos and port injection, the tuners reached the limits of my setup as my sig suggests at 625whp. Those dyno runs were done on these bosches.
OEM delphi aka s55 coils
These didn't give me any improvement at these 500+ power levels and honestly the bosch ones were better all around. The bosch ones (with 30k+ miles on them at this point) idled and did cruise control smoother whereas the delphis (new from FCPeuro) would stumble during cruise control and I noticed more variance at idle. No tune changes, just hardware changes.
PR coil kit
One of my tuners (Wedge/Ken) recommended these (and new spark plugs just to test) for seeing if I could inch my way up to 700whp, but I continued to receive misfires if we pushed past 28psi and so the bosch coils made the same power with less headaches. The PR coils did idle just as smooth as bosch so any improvement was beyond what I could notice in person or via logs. My second tuner (Twisted/Justin) believes this is likely due to a harmonics issue as I still retained my original dual mass flywheel. As I was still on stock internals and open diff and having traction issues, I accepted this was the limit of my setup.
So I actually went through a few stages here:
OE coils from the factory These had approximately 65k miles on them when I replaced them, had two go bad and has some misfire issues while completely stock and on a mix of injectors (1,2,4,9).
OEM replacement bosch coils
These worked fine from totally stock, FBO+e60+custom 24psi tune @ 455whp and even once I upgraded to MMP turbos and port injection, the tuners reached the limits of my setup as my sig suggests at 625whp. Those dyno runs were done on these bosches.
OEM delphi aka s55 coils
These didn't give me any improvement at these 500+ power levels and honestly the bosch ones were better all around. The bosch ones (with 30k+ miles on them at this point) idled and did cruise control smoother whereas the delphis (new from FCPeuro) would stumble during cruise control and I noticed more variance at idle. No tune changes, just hardware changes.
PR coil kit
One of my tuners (Wedge/Ken) recommended these (and new spark plugs just to test) for seeing if I could inch my way up to 700whp, but I continued to receive misfires if we pushed past 28psi and so the bosch coils made the same power with less headaches. The PR coils did idle just as smooth as bosch so any improvement was beyond what I could notice in person or via logs. My second tuner (Twisted/Justin) believes this is likely due to a harmonics issue as I still retained my original dual mass flywheel. As I was still on stock internals and open diff and having traction issues, I accepted this was the limit of my setup.
Just my 2c- I have run bosch all the way up to 600hp without issue.
I have been tuning with a friend's car on Delphi- to BL- PR and there were ZERO improvements to timing corrections.
If a plug fires and sparks, then it sparks, I really don't think the coils will make any difference to power or timing corrections and have seen no evidence of this.
I have been tuning with a friend's car on Delphi- to BL- PR and there were ZERO improvements to timing corrections.
If a plug fires and sparks, then it sparks, I really don't think the coils will make any difference to power or timing corrections and have seen no evidence of this.
I don't understand how coils help timing corrections either. The DME does monitor spark duration and there's a little feedback from the ignition system in theory (unproven if n54 uses the ionic combustion analysis or whatever they call it though), but really you shouldn't upgrade coils for timing corrections. You should upgrade them because you're at the power limit for reasonable gaps, because you want stronger sparks to power through e85 at low temps, reduce the chance of ignition breakup for whatever setup you're running, because heat concerns with single turbo, or other things. I've seen cars gain midrange power and smoother idle and starts but that, imo, shouldn't be the only goal. Coils don't fix every misfire, in fact the injectors are way more commonly the culprit, as is bad tuning, bad PI setup etc.
