Ignition coil Bosch or HITACHI

I also ordered four (4) new ignition coils from Hitachi, installed them 60 miles ago and it's been smooth since the installation. My car is quieter, more responsive, and idles better. No, check engine lights at all.

Be sure to use a genuine Bosch from a reputable source, or OE from the dealer. DO NOT use a Chinese one from a big-box auto parts store.

Make sure the new coil is a good Bosch, Beru, or OE unit, not parts-store brand junk. I've seen plenty of bad coils out of the box.

Did this conversion on my 2001 Audi A4 with a standalone. I ran it with stock (3ms) dwell and up to 5ms dwell and didnt notice any difference. I was running Hitatchi coils before and would notice slight bumps in idle. Now all I hear is smooth butter at idle.

The old AWD hitachi coils are far more reliable in my experience. I would not change to the awp style from the bolt downs. I have had ~8 failed AWP coils over the years on my 2001 audi/2002 gti and I have 8 hitachis now in my 2 1.8t's for a few years now and no hitachi failures. This is with track days on the gti. They also bolt down so you won't have them popping up on you whack a mole style like the awp ones sometimes do

Don't replace ignition coils until one or more gives out, then I would look into replacing them all with Hitachi E ignition coils (bolt-downs).

To make a story short, and have a happy ending like me , just buy the 1.8 T coilpack (coil-on-plug x 4) manufactured by Hitachi (Japan). They have the top of the plug filled with some ceramic epoxy-like stuff that seems really sturdy and heatproof. I bought them at ECSTuning.com over a year ago, and they haven't failed not even once.

best ignition coils ever. i've been through two other OEM revisions before finally getting the Hitachi bolt-downs from ECS.. and i've been misfire free for about 6 months now!

Performance gains from only a coil, I don't know, probably none, however the car I have it in is completely stock in the engine department. As an addition to mods I think the coil is a good idea because it helps to smooth out these cases when mixture is out of stoich Maybe better throttle response.

Car always kills them. I was the most surprised when it killed the Hitachi coils.