Jump to content
SAU Community

Recommended Posts

Hi all

This afternoon I went to the trouble of cleaning my iridiums and regapping them as the car has a slight miss above 4k revs on high boost. I thought re-gapping the plugs to .8m may make it go away. On low boost the car has HEAPS more grunt, but when you switch it to high boost it is actually worse. Very bad miss mainly around 5-7k. What is the reccommended gap to stop the missing? Its either plug gap or coils, but I dont think its the coils as the missing got worse :headspin: after the re-gap.

Any thoughts or suggestions/reccommendations?

Cheers

Link to comment
https://www.sau.com.au/forums/topic/70998-miss-at-high-revs/
Share on other sites

How much boost are you running? What engine and mods?

I have Iridiums gapped at .8 and have never had any misses throughout the rev range on my RB25. I bought my plugs pregapped at .8 and they havn't moved in 12 months or gotten excessively dirty even after running a 10% toluene mix.

You may have damaged the Iridium tips when you cleaned or gapped them?

Try a new set of copper plugs gapped at .8, its alot cheaper that getting new coils.

going to try .7 too see if it works. tried 1.1 which is the factory setting on the iridiums in the NGK book at work. That really sucked ass. Will let you know how the .7's go. I will also be trying some of the old plugs that i have to see if its a ****ed plug.

By making the gap smaller you are just hiding that fact your ignition system cannot ignite the larger gap of spark. Bigger spark means bigger power. I had to gap my down to .65 with the stock ignition system (obviously they where faulty) but now with spitfires, ive increased my gap to .9. Also the stock ECU maybe dumping too much fuel in for the plugs to fire, hence the miss. Check it out on a dyno for A/F ratios

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

    • One other question, is there a chance that changing the idle speed can lead you down a rabbit hole and is the reason the tuner didn't touch it? Reason I ask is because if that's the reason the tuner avoided it then I probably shouldn't be touching it lol.
    • Pfft. As if I'd ever point a high pressure washer at my car.
    • The nature of my commute has changed. Way back then it was traffic lights all the way, for ~28km. It sucked. When they finally stitched the expressway together I could do a good 15+km of it at a steady 80-100 with no stopping. That alone has gotten me down to flat 10s. Prior to that it was mid-high 10s. I can't remember the delta that I saw when I got the idle down. It was only ~150 rpm, because the idle speed was never terrible, but for the delta in consumption to be noticeable it would have had to have been at least 0.2-0.3 L/100km - which is not to be sneezed at when it comes for absolute free. It's only about 50L per year, but that's ~$100. A few extra pizzas is always welcome. Note that I have a record of every tank of fuel that has ever gone through my car except for a handful put in by someone else, like my mechanic. I can show you the difference between stock RB20 and tuned RB20, stock RB5Neo and tuned, winter and summer fuel blends, winter and summer fuel blends when the ambient temperature is not appropriate for the blend, working O2 sensor, blown O2 sensor, boosting f**k out of it and frightened to boost it because it is pinging, and so on. OK, I probably can't do all that now with 100% clarity - but at the time when any of those things were in event, you could see it in the records. There's 25+ years of simple tank after tank records, so you have to look for landmarks to work out approximately how old any single record is. What's really important is the meta data and that lives in my head.
    • If you're claiming the issues are not skyline specific, then either the USA is living in the 90s / early 2000s, OR you have the issue of "survivor bias". Which is you're mainly hearing and listening to those with terrible experiences, and haven't found the guys who have cars with good decent builds and no problems. It happens in AU too, that plenty of people keep having issues, and they keep going to the workshops that are known to be shit "because I read on the internet". Even worse, are those who keep posting on the internet as though they know for a fact what something is, when they've never touched/looked at said item in their life, and again are making assumptions, based on something they read, or because it's a certain way in other cars. It's even funnier when those same people debate the facts with the people who've lived and breathed this stuff for over 15 years. Example, I've had someone tell me you can't do something with a Skyline, because they read it on the internet, except I can tell they're wrong, as I did that exact thing back in 2008 with my Skyline.
    • The funniest part I saw, was someone would bitch and moan on FB about something, Andy would be the one to respond, asking for more info, if he could contact them, what the engine setup is, what their config file was, and 95% of the responses were people just going "der! It doesn't work" and Andy going "What doesn't work?" And then going "The firmware!" And they'd go around in circles as no one could ever give information, and Haltech couldn't fault things on the bench, (especially when people wouldn't give any specifics).   Many moons ago, when Andy was back at e420c stage, he reached out to me, and asked me to test different plug and play looms for him (already had an e420c in the car on his V1 PNP loom). And he kept asking me, as I was competent enough to be able to give him some specific feedback on what was/wasn't working, how to replicate the faults etc, and work through things with him. Most people are terrible at answering the questions they're asked, or being able to provide quality feedback other than "it doesn't work".
×
×
  • Create New...