1. Will they produce as much spark as the Irridiums?

2. Will they provide the same performance or better as the Irridiums?

That'* really all I need to know about them. I know they won't last as long as the Irridiums, but it would take me a long time to rack up 20,000 miles anyway.

I do believe they offer just as much performance as any one would realisically want. I have had mine installed now for about 8 months/9k and they are still going strong.

About as much as I know is that they are one heatrange colder than stock.

I hope that'* not the case because I'm N/A'd and don't need it.

Not 100% positive on that, but I do know that less heat is good in ANY engine. it prevents preignition and allows your engine to advance timing. inducted engines just benefit more because their bigger predisposition to KR

1.) Yes, although they will not last nearly as long as Irridium
2.) Same performance, they is no performance to be gained from any sparkplug. At most it just will restore what may have been lost. ie from old plugs, wrong gap, wrong heat range


Ed

Copper based plugs (TR55 non Iridiums) will produce the same if not a slightly better spark. This is especially useful in force inducted applications. They will not last as long as an Iridium though. Iridiums will stand up to many more miles.

However.... My experience with both is this:
Iridiums will not break down at the same rate as a copper based plug. Over mileage plug gap increases in both copper and iridium plugs. The iridium plug costs more than double the copper plug and should be removed at about the same intervals and regapped whereas the copper plug would be replaced with a newly gapped plug.

Therefore I see the choice as this, buy iridiums and remove about every 30,000 miles to gap or buy copper and replace every 30,000 miles with freshly gapped. Over the life of the plugs, the cost and effort will be about equal.

At O'reilly'* in Ames, NGK copper-cores sell for 1.59 - iridiums sell for 6.99. $10.21 with tax to change out the coppers. $44.88 to change out the iridiums.

I believe the 55'* are a heat range cooler. You will want the stock heat range, stock gap for your n/a car.

I found the TR-55xi'* to be a great upgrade over OE Delco plugs. Midrange to upper RPM'* improved. The AC'* only had about 25k on them IIRC..

i just took out my iridiums @ 100,637 miles, i did not re-gap the plugs at all in that time.
the gap did open up but i did not get any loss of power or MPG(tells you how good the stock coils are).
the iridiums do provide a better spark at less volts than a standard plug, just read the ads on
the Denso or Ngk web sites. i will bring the old plugs to WCBF '07.
i did get a high RPM(over 5000 RPM) miss the last 100 miles but just on
one cylinder, so i changed all the plugs. i could have fixed the gap on the old plugs
and put one new plug in and be good to go.
the center electrodes look like new on 5 of the old plugs.
old technology vs new technology, i'll take the new technology.
i won't get into the extra power thing, but if you get a better(hotter) spark
at the same volts then thats a good thing. back in the mid '70s my drag car
put out 16.5 volts just to get a hotter spark(plug gap no more than .040)
i woud burn up my plugs(side gap) in 2 or 3 meets and that is with 40 or 50,000 volts.
that is a standard '70s plug that i made into a side gap plug.

ROD

GOD I HATE TYPING