Plug n’ Play

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One of the great things about old cars is you can selectively update them with modern technology without them turning into modern cars.

An overdrive transmission – but not air bags. Better tires for more grip. But not traction control that countermands burnouts.

Another such upgrade can be performed to an older car’s ignition system. For example, you can swap out a points-type distributor for an electronic/transistorized ignition – and a hotter coil – and get faster/easier starts and much less maintenance (though it’ll be vulnerable to an EMP in the event that happens; just hang on to your old distributor and you’ll be able to revert if the world goes dark).

An even easier upgrade is to swap out the old plugs for modern ones, which can give you better – hotter, more consistent – spark and longer life.

For example, these Pulstar plugs, which go platinum-tipped and iridium one better by increasing and stabilizing cylinder pressure during each combustion event, via what the company styles pulse power.

What’s meant by that is that the plug is designed to act as a kind of super capacitor, storing – and building – electrical energy for longer than a conventional plug is able to (chiefly because of heat build-up) and then releasing it in a torrent of energy, which more efficiently burns the air-fuel charge within the cylinder.

The company says the electromagnetic field generated by the plug also ionizes the air-fuel charge just prior to the spark event, further improving combustion and the result is a noticeable improvement in throttle response and a verifiable gain in horsepower and mileage, which the company documents on its web site with before-and-after dyno runs of various cars, including a 2012 Chevy Tahoe equipped with a 5.3 V8 that pulled 7 more horsepower and 8 additional ft.-lbs. of torque after the installation of the Pulstars (see here for more).

Well, I was intrigued and so asked Pulstar for a set of plugs to guinea-pig my 1976 Pontiac Trans Am. I haven’t got a dyno but I do have an extremely close relationship with this car, which I’ve owned for 30 years. I know it like I do my own smell, as El Guapo from The Three Amigos once said.

If these plugs make a difference, I’ll know it.

The 455 V8 takes AC Delco R45TSX plugs. They are as ancient in design as the Trans-Am’s 455, which dates back to the mid-1950s. The center electrode is blunt and the side electrode a large and clunky-looking L-shaped thing.

The Pulstars look sleek and modern, with a center electrode so finely tapered that if your eyes aren’t 20/20 you will need glasses to set the gap. Which turned out to be something of a puzzle since the OE spec for plug gap is .060 but Pulstar says to not exceed .055 gap.

So I set them at .050 and let’s see-what-happens.

I should also mention that my TA’s 455 has a hotter ignition system already – an MSD soft-touch box in place of the factory HEI (High Energy Ignition) distributor. I installed the MSD unit chiefly because it has a built-in rev limiter and that’s important to protect the long-stroke 455 from an over-revving catastrophe.

So, what happened?

The car feels snappier, more responsive to the throttle than before. I can’t quantify the horsepower gains, if any – because I haven’t got that dyno –  but it feels noticeably stronger and I’d be willing to bet it is stronger and probably in the vicinity of the 5-7 hp gain Pulstar documents were achieved in the Tahoe as well as a 2012 Charger.

In fact, the gains may well have been larger since my Trans Am started with plugs much inferior to the platinum/iridium ones that almost all modern cars come with from the factory.

The bottom line is I think the swap was worth doing – in the same way that’s it’s worth going with synthetic oil/lube over the much-inferior (in cold flow characteristics/resistance to breakdown under load/high heat) conventional oil/lube that older cars usually were filled with.

Whether it’s a pour-in or plug-in improvement, the point is it’s an improvement and without altering anything about the car that makes it a neat old car.

Pulstar has some interesting technical materials to back up its claims, which you can read yourself here.  There’s also a video – here – you can view that shows you how it works.

. . .

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  1. One of the best things I did with my ‘68 Olds Delta 88 was to install the Pertronix Ignitor ignition system and a Flamethrower coil…along with Accel wires and what were then called SplitFire plugs. Much better starting, no more misfires, and overall better feel from the seat of the pants.

    Not to mention no more futzing around with points. (I kept the old stuff just in case, of course.)

    And best of all, it all fits and looks stock, so you can get that “stealth” thing going on under the hood.

  2. I’ve always wanted to try these in my car but they’re double the price of NGK irridium plugs. A ceramic capacitor can’t double the price. They mention the use of inconel which is expensive to work with but I really wish they would bring the price down. I can’t spend 100 beans on something that might work for who knows how long.

    • Hi Anon,

      I get that; at the same time, if I got say a 7 hp uptick just by swapping plugs that was a cheap 7 hp. I suspect it may have been more than 7, too – for reasons mentioned in the article.

      • Hey Eric,

        “in the same way that’s it’s worth going with synthetic oil/lube over the much-inferior (in cold flow characteristics/resistance to breakdown under load/high heat) conventional oil/lube that older cars usually were filled with”.

        I’ve heard that it might not be a good idea to switch to synthetics in an older car, any truth to this? I’m considering switching my trusty 2002 Dakota over to synthetics and, maybe, trying these plugs. What do you think?


        • Jeremy, if the seals in your engine are in good shape there should not be a problem. I changed my ancient bus over to synthetic ages ago with no issues aside from having to use a copper washer on the drain plug to stop a slight drip. However if you have worn seals you may get some leakage with synthetic because it flows so much easier than conventional oil.

      • From what I have read on the pulstar plugs they are hit and miss as far as hp gain. Many (not all) of the test results I saw were within the margin of error for dyno runs.
        Lots of speculation about why some motors like them better than others…

  3. Can’t wait to use one in my lawnmower.

    It will shorten the mowing time from four beers down to three, leaving me with one beer to enjoy during cool-down in my rocking chair.

  4. Hi Mith!

    I should have mentioned length; in my case, the Pulstars were almost exactly the same overall and thread/electrode length as my original AC Delco plugs. I wish I had access to a dyno to chart these things… plus I’ve always been curious about just how much power the old 455 makes. I would guess around 320 based on my seat of the pants estimate, which is based on decades of driving thousands of cars. But I’d like to know!

    • Try a stopwatch?
      time to speed or distance
      1/4 mile time & vehicle weight can give a reasonable hp estimate.
      there’s probably a phone app somewhere too…

  5. Looks interesting. Would look a bit more into this to be sure it fits. Somewhere some people complain that plugs were too long.
    I’m not aware of different plugs having different lengths. If the price is within reason they seem good.

    Are they long lasting? At least like 100k plugs.


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