Jump to content
SAU Community

Recommended Posts

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

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:)

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'.

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.

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


  • Similar Content

  • Latest Posts

    • I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...