I was wondering if any of you have a performance or MPG comparison over stock plugs?











"For the strength of the pack is the wolf, and the strength of the wolf is the pack"

 

I don't have a before/after comparison, but after installing Bosch Platinum 2 plugs I get 32 mpg on the highway at 70 mph with the air conditioning on. The engine is also quite responsive. Seems the plugs certainly have not hurt! By the way, I have 6600 miles on my xB. No problems so far.

 

imo, plugs won't do much at all if you're running basically stock. Just a placebo lol.

 

Guess it could be in my head! Oh, well - I'm still very happy with my Box. I traded a 230 horse '04 Galant GTS in on mine. I don't miss the power or the premium gas bill!

 

I work for a dealer and IME
all aftermarket plugs suck.....
Have seen many problems with bosch plugs...misfire codes plug falling apart in cylinger head etc.....

 

well i like to drive faster than 70 on the highway. I have dc ceramic headers. since here in dekalb illinois we do not have any emission test i have a dc full exhuast system minus the converter.oh yeah a AEM CAI cold air intake. I keep hearing about OBX IRIDIUM SPARK PLUGS and wanted to know if i should believe the hype? thanks

 

I just put the Denso Irridium plugs.....I have to clock a few tankfuls before I know the results.....wouldn't claim any performance gains at this point...

 

Me too. I installed Denso iridium plugs a week ago.

I -think- the car runs better than ever.
btw: I opened the gap to a very wide .055". This will strain the coils. However, I have no trouble as yet and maybe never.

Brent, this is a pretty iffy thing to do so I don't advise others to gamble.

The spark of a platinum or iridium plug propagates differently and 'better' than that of a conventional plug.

A wider gap tends to make a hotter spark and a physically longer spark. This sets a marginal mixture off on fire better.

Denso, if they are to be believed, state modest claims both for improved power and fuel milage. Modest is the keyword.

All I know is that my box zips much better than Ray's stock box down the street. But I've done other things to my car to account for its definitely superior acceleration and braking.

OEM plugs are fine but iridium is better "science". I don't know of any defects yet in the Densos. My running a wide gap will help to provoke any weakness of insulation in the plugs and the coils. Testing one two three four (grin)

 

Moved to PH

 

If you want iridium plugs go with the Denso or NGK. They work for me.

Now with the OBX plugs, tried those, they suck. Even with a 60k warranty they went bad and the company won't honor it. I had them in for 500 miles and the took a dump. Set off a CEL, had a mis-fire on 2 of them.

Better to go with the Denso or NGK, haven't heard of any problems with them yet.

 

exactly...
I gapped mine at .042 I figure 1/2 way between the .055 you set it at and the standard .032.....
with the few mods I have done it is zippier.......can't claim the plugs were a performance upgrade as earlier stated

 

if you get ngk plugs at advance autoparts they warranty them with no questions asked.

 

Wide Gapping

OK, so up front let me state that I am no expert at all. I don't even know the exact relationship between -ionization threshold re: gap.

However, the wider the gap the higher the voltage (pressure) must built -before- the spark begins.

Early autos with magnetos tended towards quite narrow gaps of .015" to .020". This was to lower the voltage requirement to spark the plug. For a magneto is a sort of generator and as such it does not produce very much current at low turning speeds, as when cranking up an early automobile engine.

With battery and coil sytems, wider gaps, usually .030" are permissible because the battery makes a constant quality of current regardless of engine rpm.

The wider gap of going from .020 to .030 definately makes for less trouble with fouling plugs and misfires due to carbon fouling in old engines.

The model T engine is more prone to soot-fouling its plugs than more sophisticated engines of that period. I drove Model T for nearly 25,000 miles in Miami city traffic. I know Model T intimately in every detail.

Doing research for a better spark plug for Model T than the poor repro plugs available today for that engine, I determined to fit a modern plug, using plug adaptors readily available to the hobby market. But what plug to use?

I investigated and found the Bosch single side electrode #4203 to be the best deal. At that time, about five years ago this Platinum plug cost less than two dollars at local auto parts stores.

It featured a very long, extended nose which put the flame kernel well out into the combustion space of primitve cylinder head.

I experimented with various gaps. In my engine I found the wider the gap the stronger my engine ran. I was using a single coil igntion with Pertronix electronic breaker in a Bosch VW type distributor.

Because the T engine is of such low power but high torque, small inprovements in power delivery are quite surely felt by the driver attuned to his car's habits.

Widening the gap made the car start better from cold, and accelerate faster. Ultimate top speed was not much or any affected. But throttle response seemed much better.

Also, throttle-closed, with a wide gap, the engine did not afterfire in the muffler anymore. Key point: this demonstrated irrefutably that a wider gap made a better spark and this better spark was much more capable of igniting a marginal quality mixture successfully, to burn completely while in the cylinder space instead of sending raw fuel out the exhaust manifold to pop off there.

-I ran the T with Bosch single platinum plugs with .090" gap in the final year. I did spoil a plug or two by insulation breakdown. It was worth it though. For the wider the gap, the more smartly the engine ran. Now, that won't apply so clearly to a refined modern Toyota engine, but it does prove the trend:

a wider gap makes a hotter, higher current spark of greater physical length which will set off the combustion in a surer, more consistant way each cycle.

(essay not proofed)

 

Let me add some more difficulties introduced by a wider gap (not necessarily applicable to the Scion engines:

-the spark plugs, even though well ribbed, would snap off to ground if wet or damp from dew. This meant: WD40 could be needed to spray on the Bossh plug's external porcelains some of the time. To displace the water film.

Also it was most definitely required to "fly" the spark plug leads using stand-offs.

All in all the setup worked much better than with narrow gap

The Scion engine does not have plug wires to short nor can water get on the porcelains and leak off the current. Therefore, IF the scion's plug-coil units can stand the strain that a regular 12V single coil withstood taking the guff of like 40kV, then ok! I -could- gap my Scion's irridiums even wider.

but would there by any point to it? Dunno. I would want a dynamometer to separate reality from placebo effect.

 

the the slightly bigger gap I am running I don't see much difference yet.....do see any SciFly?

 

I -think- so but I will not say definitely. Placebo effect rules us all.

Objective tests properly conducted are the only true determinant.

I definitely can run circles around a stock box though. (my car is stripped of excess seating and is on smaller diameter tires than stock). Plugszez prolly add a bit more sugar to the real Pill now but hell, I don't need more power. I just like to ensure best operating efficiency.

 

i installed the iridium sparks also. they gave me an extra gallon's worth of fuel or about 30 miles. its true i clocked my fuel since the first fill up.

also about gapping it..my understanding is that you are not supposed to gap the iridium sparks.


overall..yes it does work..let me know if you need any.

 

it said on the box..no need to gap...mine measured .042 so I left them there based on all the info I read...

 

I've got about 12,000 miles on my NGK Iridiums so far. A couple days ago I pulled them to see how they look and decided to increase the gap per what I've read here recently. MAN!!! Are those side electrodes tough!! I had a hard time getting them to move in order to make the gap larger. Finally got them all to .050 as near as I could read/feel (feeler gauge??) While I was at it I also marked the plugs so I could check the indexing. Two are perfect and two are 180* out. I did not try swapping plugs to see if the index moved. Wouldn't have done me any good as I don't have spares, and at 7.00 each I'm not buying any either!
The plugs appeared to be burning properly, not too hot or cold. No deposits/soot to speak of. Earlier experience with small car engines/plugs I felt they were usually too hot. Even had aluminum deposits on one Datsun with normal heat range plugs.
I think SciFly is probably right... it's a placebo effect!!!