Jump to content
SAU Community

Recommended Posts

today i've installed SACFII and AVCR. i'm going to run 1.0 bar pressure on stock turbo, but there is some kind of a sound like iron knock... is it a detonation? i've also a backfire always above 0.5 pressure... hope the spark plug gap to 0.7 will fix it.

what i would like to know is will the lower gap (0.7) fix my problem of backfier or not?

btw, i'm trying to measure the A/F ratio with Apexi turbo timer :) thanks.

Link to comment
https://www.sau.com.au/forums/topic/22768-avcr-and-safc-install/
Share on other sites

Originally posted by Robo's

Check your A/F ratios, this could be your backfire.  Too much unburnt fuel.

can the detonation happen on rich mixture? because it backfires on 1.0 bar too but it looks like it detonate... it also backfires on 0.5 bar. i thought that detonation happen only when the fuel mix is too lean, but how then the backfire happens?

i thought audible detonation sounded like a tin can shaking around with nutz and bolts in it. could that sound be just vibration noise from the exhaust or turbo heat shield?

does your check engine light come on when you hear this noise? i've registered 150+ on my powerFC for knock and i've still not heard detonation. i believe you're alot more susceptible to detonation when you start advancing ignition timing.

i just can't imagine how an increase in boost and some fuel adjustments could be making the car detonate (unless you've taken out alot of fuel and your running a shitload of boost).

i wouldn't trust a/f ratios from a turbo timer. you are best to get it tuned on a dyno with the sniffer up the exhaust.

Originally posted by INASNT

LOL

How exactly are you measuring the a/f ratios??

My Apexi turbo timer shows it... but it actually sucks, i tried to make a very rich mixture, there is a black smoke from the exhaust, but Apexi still shows 14:1 :) no Dynos here....

Franks, check engine didn't flash - should it? but yes, i think it "sounded like a tin can shaking around with nutz and bolts in it". just didn't know how to describe it... i will try to configure the knock sensor on the SAFC and see if it is a denotatation or not.

Guest INASNT
Originally posted by Vovan

My Apexi turbo timer shows it... but it actually sucks, i tried to make a very rich mixture, there is a black smoke from the exhaust, but Apexi still shows 14:1 :D no Dynos here....

Franks, check engine didn't flash - should it? but yes, i think it "sounded like a tin can shaking around with nutz and bolts in it". just didn't know how to describe it... i will try to configure the knock sensor on the SAFC and see if it is a denotatation or not.

your turbo timer has a sensor plugged into the oxygen sensor??

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...