spark plug gapping

dark_knight

dark_knight

Member +
uncertain if this is the right section for this but it's the closest.. :)

searched for a bit but most people are talking of plug heat ranges and not gapping. so, if running near-stock parameters, what's the recommended plug gapping..?
i'm running 0.8mm on NGK BKR 6E1X but have been reading around that i need to be gapped at 1.1mm if running stock turbo, 0.9mm if running up to 1bar and 0.7mm if running up to 1.3bar.

my base spec list is: blitz air element, kakimoto exhaust (de-cat), ct9b @ 0.75bar.
so.. what's recommended..? for the stock setup that is, since i think i classify as running stock..
 
dac69er

dac69er

Super Moderator
i would run 1.1mm. bigger gap gives a stronger spark, but it higher boost levels you can get spark blow out problems, so a smaller gap is sometimes needed. obviously a larger gap requires your ignition system is 100% and you have good ground points around the engine.
 
dac69er

dac69er

Super Moderator
Paul_JJ said:
Bigger gap more economical, smaller better performance -) I would stick to factory 0.8 mm Iridium
Click to expand...

this is not strickly true. and the factory gap is 1.1mm on a GT. i have seen people say it should be 0.8 on a glanza, but due to never owning a glanza i dont know. all 4efe's are 1.1mm too.
 
spuddy

spuddy

Ulster Area Rep.
1.1 should be fine, never had any issues on the stock ignition system up to around 1.7bar on a TD05.

Even now I run 1.1 tested up to 2.45bar on a larger turbo again, on coil packs though.
 
dark_knight

dark_knight

Member +
thanks folks

thanks all for all your input. re-gapped mine to 1.1 from 0.8mm so will see how that turns out.. :)
repped all, just for being a sport..
 
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Paul_JJ

Member +
dac69er said:
this is not strickly true. and the factory gap is 1.1mm on a GT. i have seen people say it should be 0.8 on a glanza, but due to never owning a glanza i dont know. all 4efe's are 1.1mm too.
Click to expand...

Performance plugs have smaller gap, every major spark manufacturer company sell 0.8mm for both 4efe and 4efte

EP82 and EP91 - pretty much the same engine, just slight difference.

http://www.custom-car.us/ignition/spark-plug/gap.aspx
"Ironically, the car manufacturer's recommended spark plug gap is not optimal! The recommended spark plug gap is designed to be adequate for cold starting and smooth driving on a car that is in need of an engine tune up. If you drive your car normally and tune the engine regularly, you can increase the spark plug gap by about 0.010" for better performance and better fuel economy. However, if you drive at full throttle most of the time, you should reduce the gap by about 0.010" for better performance. Ultimately, you'd need to run your car on a dynameter to find the best spark plug gap, and the right ignition timing for your engine."


http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp
Gapping

Since the gap size has a direct affect on the spark plug's tip temperature
and on the voltage necessary to ionize (light) the air/fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability
in these denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.
 
dac69er

dac69er

Super Moderator
yes, but you should try and run a larger gap if you can. you do often need to run a smaller gap when modified, but for alot of people on here the standard 1.1mm gap is fine.
 
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Paul_JJ

Member +
dac69er said:
yes, but you should try and run a larger gap if you can. you do often need to run a smaller gap when modified, but for alot of people on here the standard 1.1mm gap is fine.
Click to expand...

I have tried both -) I had standard plugs 1.1 and put Iridium 0.8 the difference was minimal, but 0.8 felt a bit quicker.
 
Chris@CCM

Chris@CCM

Member +
1.1 if it misfires at high load (if ur running big boost ) start taking the gap down I've had to run .6 a few times on high boost cars
 
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Paul_JJ

Member +
spacecraft said:
0.6mm sounds a tad small, but i'm guessing this is for super-modded engines..
Click to expand...

You can read a lot of literature about it. not many tuners will know about this kind of tuning. We're all know that Chris@CCM is a real pro!

Everyone knows that the spark plugs are one of the most important part in the whole engine, but how many people apply the correct torque [which is CRUCIAL] when changing them, using the torque wrench?
 
dark_knight

dark_knight

Member +
arm wrench

@ Paul_JJ: what if i don't have a t/wrench..? can i use my trusty arm that's been torquing stuff for 3+ years now to gauge how much force i'm putting in..? :) hehehe
 
dac69er

dac69er

Super Moderator
you dont need to torque down spark plugs if you know what you are doing. just do it by feel ;)
 
R

Rev

Member +
I find a big difference with different sparks. Have heard .6 to .8mm give no problem with copper plugs I am currently .9 mm copper . Good to hear spuddy input that 1.1 mm is OK at high boost I am all for a bigger spark surface as possible but I guess that 1.1 mm is with low temp irridiums ? I used irridiums at about .8 with 20psi boost the tips seems to wear to about 1.2mm over time. It is my understanding the irridiums will have less surface area than a similarly gapped copper core so the copper core will give more low rev torque. I increased fuel consumption going to copper with new leads because I was having so much fun driving harder. Auto usually revs much lower than manual box so notices the low rev torque. I have heard more torque properly applied should give better consumption.
 
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Paul_JJ

Member +
Do you seriously think that you know more about the spark plugs then NGK or Denso or Bosch or Champion?

http://www.ngksparkplugs.com/techinfo/spark_plugs/installation.asp

1. Installing spark plugs

Torque is one of the most critical aspects of spark plug installation. Torque directly affects the spark plugs' ability to transfer heat out of the combustion chamber. A spark plug that is under-torqued will not be fully seated on the cylinder head, hence heat transfer will be slowed. This will tend to elevate combustion chamber temperatures to unsafe levels, and pre-ignition and detonation will usually follow. Serious engine damage is not far behind.

An over-torqued spark plug can suffer from severe stress to the Metal Shell which in turn can distort the spark plug's inner gas seals or even cause a hairline fracture to the spark plug's insulator...in either case, heat transfer can again be slowed and the above mentioned conditions can occur.

http://www.globaldenso.com/en/products/aftermarket/plug/basic_knowledge/installation/index.html
"use a plug wrench to tighten them accurately to the torque"

http://www.boschsparkplugs.net/charglossary.asp?kw=Plug+torque+settings
http://www.championsparkplugs.com/charglossary.asp?kw=Plug+torque+settings


Of course it will be ok if tightened by hand, but for the best performance.....
 
dac69er

dac69er

Super Moderator
i dont claim to know more than spark plug manufacturers. but if you read any manual you get with almost anything nowadays it states that everything should be done a certain way to stop plebs fucking things up.

if you over torque the plugs in an alloy head to the point of damaging the plug you will most likely rip the thread from the head first. if you undertorque them, then you will probably eventually have the plug come loose.

if i remember correctly. ngk sparkplugs come with a little diagram on the side of the box. shows that you do the plug up until the washer is compressed and then an eighth of a turn or something like that. no mention of torque. once the washer is compressed doing it by feel is not a problem if you know what you are doing.
 
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