I gave this to Jake and Martial in November but no idea if it made it live. Should probably check and find out lol.
VTT / Precision Raceworks Coil install / Results thread
- Thread starter Tony@VargasTurboTech
- Start date
I gave this to Jake and Martial in November but no idea if it made it live. Should probably check and find out lol.
Longevity of what? The coils or plugs or both. After replacing the old harness and making minor physical modifications on the coils, my car runs perfect... on my third tank of gas and still no problems. Neither with 93 or e85 are there any issues at all.
With the old harness and unmodified coils the car ran .030 for one week and then started to misfire.
Unfortunately given the date of the post, we know that the coil setup Alex was testing with wasn't touching the plugs, so I wouldn't put much stock in the observations. For longevity, I'd recommend not having the coil tip jump the air gap to the spark plug on its way to the electrode tip.
Frankly I've seen no explanation that I've understood relative to plug gap, beyond some comments from tuners that over 0.022" seems to have no effect on performance, so no reason to have the ignition system work any harder than it has to.
We've seen people here run from 0.016" to 0.030+" ... with varying experiences of no misfires to misfires. Including ... "it ran fine for a while, then started misfiring" ... then we get into the plugs. Unfortunately not very cut and dry. I think the guys doing lots of tuning have the best insight, which may be from repetitive feel, but that's just my guess.
For now I returned to Eldors with 97550s ... and will leave it alone until turbos go on the car.
Filippo
From my understanding easiest thought experiment to explain is imagine gal of water water being ignition energy. Now as your spark gap increases you require a larger hose to fill that gap with water from your gallon . So in essence a larger gap uses up all your water quicker meanwhile a smaller gap requires less energy ex smaller hose and your gallon will last longer . Basically you need more voltage for larger gap leaving less amperage for duration. This is why larger gap has diminishing returns even if not misfiring cause you get more complete burn with longer spark duration
Yes ... but another factor is the insulators are like your garden hose - the higher the pressure build up, the more wear and tear on your insulators. So diminishing returns there as well.
Filippo
Filippo
without wishing to stray too far off topic, but what are your thoughts on running Delphi GN10571 coils? After all, these standard fare on the S55 which runs up to 22psi + water injection in an OE application with OE durability. Best of all they're cheap and fit perfectly...
People have been using them for years, they're the same coil that the PR and BL set are upgrades from. The Delphi are really no different for our application than the old Bosch ones that originally came on the N54 aside from aesthetics.
Why is it then that these run without issue on the S55 and S63tu (which uses a very similar looking version with probaby detail differences) ?
It's the plug that's diff that's why s55 plugs can be run at stock gap for many. Also 22lb on one car doesnt equal 22lb on another car stock, we may be seeing higher cyl pressure. If car is modded and putting down over 500 hp it's fair to say it has higher cyl pressure
S63 is way less power dense than n54 or s55, and the plugs do make a difference. Also factory coils do ok with power levels up to and over 500hp in the higher cylinder pressure inline 6's nobody is saying they don't, but it does take increasingly smaller gaps as you get higher, and the coils aren't really all that reliable. Bosche did the original design and was succeeded by delphi as the oem manufacturer with the n55 and s55 which was then replaced by eldor as the new oem distributor, all using the same design from the n52. Only design change was like 10 years ago when they changed the way the coil engages the plug to the flat spring thing. They are adequate sure. But they are definitely not a high performance coil or a benchmark for reliability lol.
Yeah but keep in mind that these coils have no issue with 600+ whp tuned S55s and S63s still running the stock plug gaps. Also FWIW, GN10571 is the latest OEM design, and not Eldor.
Wait you're using factory s55 plugs? You really shouldn't, they kinda suck and are failure prone with cracking, seen it a few times. I recommend colder plugs on the s55 and n55, and I recommend .018" gap for over 25psi just like on the n54. I've not seen as many misfire issues on the s55 but it's a totally different engine. I haven't tuned one in a while but I'm pretty sure things haven't changed on that front. The s63 is a v8 and much more forgiving.
Like he said, the coils work. If you want to run them, go ahead. But there's several threads in these forums (including the one you're reading) where there is solid data showing there's gains to be had from moving to a better coil setup than what came from the factory. Not to mention needing to replace them a lot less often. Since I started really modding the N54 coils have been changed just as often as plugs for me, because just doing plugs didn't restore the car to how I wanted it to run.
The golden question what plug would you rec @v8 for fbo or fbo plus n54
