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they run the best in my 12v V6. I tried the Bosch
multi-electrode plugs, and my engine didnt like'm.
Tried the NGK's, and my engine liked'm better than the Bosch's, but still had issues. Tried the A/C's, and all was well. Especially if I run my Nology wires. They are one of the few plugs that will survive on the Nology wires.

At the time, their price was more reasonable than many of the other plugs.

I like their design, as they closely resemble the Iridium plugs, but without the cost.

I gap mine slightly more than OEM spec's.

Recently, I found'm on Ebay for $2 each, so I bought several sets. ;O)

I ran that for almost every car I owned. For me, they have better throttle response than platinum +4s and smoother idle.

Too bad they don't make it for my 30v, or else I would be running them.

ever tried beru ultra x?

.

Motor ran better than with all other spark plugs I've tried, but I suspect the 5/6 heat range was a tad too cold for my stock motor. I didn't want to risk carbon build-up, so I went back to the NGK plugs. JWG runs the Ultra-X, and he loves them, but his engines puts out significantly more that stock. If I were to try the Ultra-X again, I'd feel safer with one heat range up (7/9): Ultra X-UXF7.9

..They have those Delcos on Ebay right now for $2, my plugs are due and I'm tempted to fit them in my A4. Interestingly the AC Delco doesn't list a plug for the 90 or A4. So how did you figure out they would work?

A couple years back, the A/C Delco #9's were sold thru AutoZone, for the Audi 12v v6. Thats where I first acquired them...

IMO, a bit excessive for non-turbo motors...

Has anyone tried the HKS Iridium Plugs?

However, they will sell you a set, at over $12 each, and tell you they install in anything...

When Iridiums first came out they were soley intended for turbo motors, but have seem'd to migrate over to the NA motors.

Again, IMO, a spark plug costing over $12 each is overkill for the Audi 12v V6. Especially a "bone-stock" 12v V6.

However its your cash...

Would they be a good buy?

I don't even see any advantage in running platinum plugs. Electric conductivity of platinum plugs is actually lower than those of ordinary copper plugs. Platinum is just longer lasting. As for iridium, doesn't that stuff belong in satellite phones? ;-)

Just wait till the makeup comes off -- and likely some parts. :-P

To buy the lowest cost/best performing spark plugs I can find.

Why?

You can easily spend the cash on a set of Iridiums, and find out they wont give you anything more than the $2 sparkplugs...

<ul><li><a href="http://www.sparkplugs.com/results_app.asp?productTypeID=1&amp;AAIA=1008694">http://www.sparkplugs.com/results_app.asp?productTypeID=1&amp;AAIA=1008694</a</li></ul>

Which ones would you get?

Denso
or
HKS

I'm done wasting my cash on those type of plugs.

I cant recommend one, as I have never bought either, so I cannot say which is the one to buy.

I endorse the A/C Delco's because I've run them for years. ;O)

With the OEM wires, .042-.045.

With the Nology wires, .050-.052

All though I have run the OEM wires on a set gapped to .051, as I changed over from the Nology wires, and left the plugs in. ;O)