Which AC Delco Spark Plugs on TA Alum Intimidator Headsfor street use?

[trick86]

Hello All,
TA Perf recommends NGK R5671a7's as the hottest plug availbe, some have suggested it's a little on the cool side for street use and has a tendency to fool. I'm in search of a equalent to the following as I've had good luck with R43TS in stock heads and FR3LS's(41-629) in MA Aluminum heads at 17 psi on pump 94 octane. As a die hard AC Delco fan what is the hot' ticket for AC Delco plugs in TA Aluminum Intimidator heads?(street use)...Bison feel free to chime in.
Thanks guys

 

[turboclam]

I'd like to know too.

 

[forzfed]

Doesn't NGK make AC Delco?

 

[CGASTON]

You need to run a non projected tip plug. I run AR 134 in my iron heads, but will work for you.

Sent from my iPhone using Turbo Buick

 

[Nick Micale]

I know this does not answer your question, but after having MANY issues with AC Delco plugs in street and strip cars years ago, that is one brand plug I will never use again.

First, never use an extended tip plug in a turbo engine.

Second, the TA heads require a 3/4" reach plug, which is not the same as an iron head.

I know TA recommends the NGK plug, but I actually use Autolite race plugs as they have always performed well, and I am not going to cheap out on a set of plugs with a set of heads which are usually in excess of $2500.

The Autolite race plug series for these heads is AR 393?. The numbering starts at 3931 which is the very cold plug which we use for high HP E-85 applications.

The numbering runs 3932, 3933 and up to 3934 which is a normal street plug. We always start with a cold plug, and carefully move up to a hotter range as we determine it is safe for a specific build and HP level.

 

[RIFF RAFF]

NICK , ONE MORE THING . EXPLAIN WHY YOU START COLD THEN MOVE TOO HOT . PEOPLE NEED TO GET THIS INFO .

 

[Nick Micale]

NICK , ONE MORE THING . EXPLAIN WHY YOU START COLD THEN MOVE TOO HOT . PEOPLE NEED TO GET THIS INFO .

A plug that is too hot is the primary cause of pre-ignition as the electrode will be the hottest place in the combustion chamber which can light off the charge before the piston is up in place for proper ignition.

In many cases of too hot a plug, especially at high boost, the side electrode and part of the ceramic tip will be gone.

A cold plug will make it more difficult to light off the charge, and the downside is the plug will foul quickly, or not last very long. A plug is less expensive than a piston.

If alky injection is being used, plug selection is VERY critical and necessary to avoid disastrous results. When injecting 100% alky, this mixture is very susceptible to hot spots, especially the spark plug. This is one reason most users, other than turbo Buick owners here, use a 50/50 mix so it is less likely to cause pre-ignition.

The proper plug and gap also applies very much to E-85 use as well.

Unlike most owners here, I have seen and repaired MANY 100's of damaged engines over the years, and it is important to find the cause so we can learn how to prevent future disasters.

 

[Boostdeznuts]

Nick for 3933 what is the gap for them ?

 

[RIFF RAFF]

A plug that is too hot is the primary cause of pre-ignition as the electrode will be the hottest place in the combustion chamber which can light off the charge before the piston is up in place for proper ignition.

In many cases of too hot a plug, especially at high boost, the side electrode and part of the ceramic tip will be gone.

A cold plug will make it more difficult to light off the charge, and the downside is the plug will foul quickly, or not last very long. A plug is less expensive than a piston.

If alky injection is being used, plug selection is VERY critical and necessary to avoid disastrous results. When injecting 100% alky, this mixture is very susceptible to hot spots, especially the spark plug. This is one reason most users, other than turbo Buick owners here, use a 50/50 mix so it is less likely to cause pre-ignition.

The proper plug and gap also applies very much to E-85 use as well.

Unlike most owners here, I have seen and repaired MANY 100's of damaged engines over the years, and it is important to find the cause so we can learn how to prevent future disasters.

THANK'S NICK .. IF MOST PEOPLE UNDERSTOOD THIS .. WE WOULD HAVE LESS TECH QUESTIONS TO ANSWER . OR WHAT CAUSED THIS TO BLOW APART ? I USE AUTOLITE ALSO .. NEVER ONE PROBLEY .UNLESS IT WAS MY FAULT .

 

[GBGN1]

So why do champion heads and ta heads take different plugs?

 

[Quik Six]

I ran Autolite 23's for several years and switched to AR23's a couple of years ago. They did very well at the track but were a little too cold for street use so switched to AR24's. Running 93/alky combo and it works pretty good.

 

[forcefed3.8's]

The Autolite race plugs wear out quickly. They have a cut back ground strap that wears the center electrode on one end, causing an increased gap. I haven't fouled an AR3932 yet, but have worn out a few sets.

 

[Quik Six]

The Autolite race plugs wear out quickly. They have a cut back ground strap that wears the center electrode on one end, causing an increased gap. I haven't fouled an AR3932 yet, but have worn out a few sets.

Very fast car!

Thanks for the heads up. I'll watch the plugs for the wear you described. They've performed well so far with 93/alky and not more than 25#'s of boost. C-16 fuel and 28+#'s of boost will probably change the ball game and based on what you've said and Nick posted, I'll go the AR3932.