Jump to content
SAU Community

Oh NO! Not another plug choice thread!

rev210

By rev210,
in Engines & Forced Induction

 Share

Recommended Posts

rev210 Grand Master

rev210

Posted
Posted

Thats right it's another thread on plugs!

I have a question about plug choice for those who are reving the engine to a peak power around 7000rpm on the stock turbo:

What plugs have you tried against what you are running and are happy with now?

I have 6ES units at 0.7mm gap, but since I have a S-AFC I was thinking of going to 7's or 8's with a larger gap.

My old rule of thumb for every car from rotory to V8 is 6's for 6000rpm , 7's for 7000rpm and 8's for 8000rpm etc.

For my old ported chooker it was 6's for traffic driving (don't fowl easy) and 9's for spirited driving.

Link to comment
https://www.sau.com.au/forums/topic/11576-oh-no-not-another-plug-choice-thread/
Share on other sites
Steve Grand Master

Steve

Posted
Posted

Rev210, I am using BCPR6ES gapped at 0.8mm. They seem to do a better job than the stock ones that were in there. dont have any probs up to 7250rpm @1bar boost or pulling from low revs in a high gear. Idle quality is good and starts well. I am very pleased with them.

'For my old ported chooker it was 6's for traffic driving (don't fowl easy)'.....hehehehe dont know if a pun was intended, but I found it amusing anyways:)

rev210 Grand Master

rev210

Posted
  • Author
Posted

Steve,

Pun intended.

the 6ES is what I have at the moment, gapped to 0.7mm (0.8mm is not as good with the timing I run). They are a pretty warm plug.

The 7ES equivilents I have in the form of Auto-lite racing plugs proved a better option for higher rpm use, I had them gapped to 1.1mm. The only problem with them was that I had them on the stock ecu with fewer mods than I do now. The plugs became fouled at the lower speeds I used 'around town'.

Steve Grand Master

Steve

Posted
Posted
Originally posted by rev210

.....

The 7ES equivilents I have in the form of Auto-lite racing plugs proved a better option for higher rpm use, I had them gapped to 1.1mm. The only problem with them was that I had them on the stock ecu with fewer mods than I do now. The plugs became fouled at the lower speeds I used 'around town'.

Isnt this the problem with going colder - they work at a higher rpm and better for bigger hp but you get a trade off. Perhaps you could

a. Change them frequently....

b. Get the car down to the plex more often

c. Driving around in first - only in built up areas of course.

Xeron Enthusiast

Xeron

Posted
Posted

hrm i cant remember what the figure is, it could be 150, too much beer in my head lately.

The way i understand it is, a colder spark plug will remove more heat from the combustion chamber, 70-100 degrees more quoted from NGK. What this means is, if your running too hot a plug, it will retain too much heat and cause detonation in your engine. Too cold a plug will foul quickly as it wont remain hot enough to burn off deposits.

A larger gap makes it harder for the ignition system to throw a spark over this gap. This can cause miss fire at higher rpm, so if ur running ur engine at a redline higher than stock, and ur experiencing missfire at wot, u might want to try dropping the gap .1 or more.

Hope i made more sence now that im sober :P

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I neglected to respond to this previously. Get it up to 100 psi, and then you'll be OK.
    • MBS206
      Mistakes were made, my R34 Story

      By MBS206 · Posted

      I agree with everything else, except (and I'm rethinking this as it wasn't setup how my brain first though) if the sensor is at the end of a hose which is how it has been recommended to isolate it from vibrations, then if that line had a small hole in, I could foresee potentially (not a fluid dynamic specialist) the ability for it to see a lower pressure at the sensor. But thinking through, said sensor was in the actual block, HOWEVER it was also the sensor itself that broke, so oil pressure may not have been fully reaching the sensor still. So I'm still in my same theory.   However, I 100% would be saying COOL THE OIL DOWN if it's at 125c. That would be an epic concern of mine.   Im now thinking as you did Brad that the knock detection is likely due to the bearings giving a bit more noise as pressure dropped away. Kinkstah, drop your oil, and get a sample of it (as you're draining it) and send it off for analysis.
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I myself AM TOTALLY UNPREPARED TO BELIEVE that the load is higher on the track than on the dyno. If it is not happening on the dyno, I cannot see it happening on the track. The difference you are seeing is because it is hot on the track, and I am pretty sure your tuner is not belting the crap out of it on teh dyno when it starts to get hot. The only way that being hot on the track can lead to real ping, that I can think of, is if you are getting more oil (from mist in the inlet tract, or going up past the oil control rings) reducing the effective octane rating of the fuel and causing ping that way. Yeah, nah. Look at this graph which I will helpfully show you zoomed back in. As an engineer, I look at the difference in viscocity at (in your case, 125°C) and say "they're all the same number". Even though those lines are not completely collapsed down onto each other, the oil grades you are talking about (40, 50 and 60) are teh top three lines (150, 220 and 320) and as far as I am concerned, there is not enough difference between them at that temperature to be meaningful. The viscosity of 60 at 125°C is teh same as 40 at 100°C. You should not operate it under high load at high temperature. That is purely because the only way they can achieve their emissions numbers is with thin-arse oil in it, so they have to tell you to put thin oil in it for the street. They know that no-one can drive the car & engine hard enough on the street to reach the operating regime that demands the actual correct oil that the engine needs on the track. And so they tell you to put that oil in for the track. Find a way to get more air into it, or, more likely, out of it. Or add a water spray for when it's hot. Or something.   As to the leak --- a small leak that cannot cause near catastrophic volume loss in a few seconds cannot cause a low pressure condition in the engine. If the leak is large enough to drop oil pressure, then you will only get one or two shots at it before the sump is drained.
    • GTSBoy
      Help! Leak coming under transmission

      By GTSBoy · Posted

      So..... it's going to be a heater hose or other coolant hose at the rear of the head/plenum. Or it's going to be one of the welch plugs on the back of the motor, which is a motor out thing to fix.
    • MBS206
      Mistakes were made, my R34 Story

      By MBS206 · Posted

      The oil pressure sensor for logging, does it happen to be the one that was slowly breaking out of the oil block? If it is,I would be ignoring your logs. You had a leak at the sensor which would mean it can't read accurately. It's a small hole at the sensor, and you had a small hole just before it, meaning you could have lost significant pressure reading.   As for brakes, if it's just fluid getting old, you won't necessarily end up with air sitting in the line. Bleed a shit tonne of fluid through so you effectively replace it and go again. Oh and, pay close attention to the pressure gauge while on track!
×
×
  • Create New...