: It's been asked before, but more specifically.ACD 41-OEM Sparkplugs vs Denso Iridium

04-17-11, 05:12 PM
Im at 109K miles....

Denso is the OEM for the N* double platinum spark plugs (AC Delco 41987 double platinums are EXACT same plug as DENSO PT16EPR13 aka 5092).

As per the Denso site (http://goo.gl/TyKuB ), their Iridium plugs are compatible with the N*

Rock Auto page for AC Delco 41-987 http://www.rockauto.com/catalog/moreinfo.php?pk=89945
Rock Auto page for DENSO 5092 (same spark plug as above) http://www.rockauto.com/catalog/moreinfo.php?pk=993026

Here's the Rock auto page for the Denso Iridiums: http://goo.gl/24G7u

So what's your take? Not worth the extra dollars or not a noticeable upgrade? Reducing the load on something so repetitive would have some kind of advantage, or a fiasco like Bosch plugs in the Northstar?

My reasoning is the original plugs are DENSO and these are DENSO too--not just a gimmick, same engineering.

Also, would there be a noticeable improvement in MPGs with new plugs?

04-17-11, 06:54 PM
I seriously doubt you'd see any difference in mileage.

04-18-11, 02:19 PM
Stick with the factory recomendations and put another 100K on it.

04-18-11, 03:33 PM
Well they were only $12 more than the factory ones for the whole set. I'll report back if they fail to perform.

04-18-11, 03:34 PM
I just ordered 8 AC Delco 41-987 from ebay. ~$4 each. Trying to stick with AC Delco, proven...

04-18-11, 04:12 PM
I just ordered 8 AC Delco 41-987 from ebay. ~$4 each. Trying to stick with AC Delco, proven...

Yeah can't go wrong. That's what I was going to do, but since the AC Delcos are made by DENSO and according to them their Iridium is one up on their double platinums I took a chance for $1.50 more each than the AC Delcos. $3 more each than the DENSO label double platinums.

I got them from retailer in case they are a fiasco, I can get a refund/exchange for the ACDelcos/stock DENSOS.

I notice only the escalade is using Iridiums, all the Cadillacs still use the double platinums when I checked (I hope that's not a sign).

johnny kannapo
04-18-11, 04:21 PM
The Iridium plugs are a teeny bit less demanding on the coils and that is the advantage to them.

If a Denso Iridium plug fits the spec. coil life maybe extended by using them. You really can't go wrong using the OEM plug.