Jump to content
SAU Community

Recommended Posts

just thinking about things... my car is knocking way more now than what it did before the tune.... All we did at the retune was pull back the ignition timing (in effect that should lower the knock substantialy) and leaned the Air Fuel Ratio to 12:1. The tempreture outside when we tuned the car was around 28-30 degrees and now that the air is cooler it becomes more dense... therefore the Air Fuel Ratio would lean out, Correct?

I gather this must be the cause of why my car is knocking so much now.... Does a lean AFR make the car knock??

Yes, lean AFR makes the engine knock. There is less fuel in the combustion chambers hence more heat and knock, put more fuel in which reacts as a coolant and then you have less heat and knock. Hence why factory cars are generally run rich from factory to act as a safety measure.

The old saying is, lean is mean!!! Its great for performance but its living life on the edge. But, 12-1 ratio should be what your aiming for, maybe high 11's if you continue to have troubles.

I had my car tuned at ICE with the PFC...

Just PFC, FMIC, Exhaust on 12psi

It was knocking on the top end of 2nd and 3rd so i took it back.. Nigel told me it was totally safe this time (2nd Tune) but the car still shows the knocking light flashing when in low revs in higher gears...

The light comes on even when i lowered the boost to 9psi which to me says the car is running to lean?

Without a Hand Controller and only Nigel telling me it will be fine, how sensitive is the knock sensor on the PFC?

The dyno really graph really doesnt tell me much whit the ratios at 12-12.5:1 on the first tune by ICE...

Any ideas?

well before the tune my car used show a knock level of 15-25 under hard hard acceleration. Today just hard acceleration it pulled way over 65 knock both times i did it... Not particularly pleased. I know from when I was racing my Formula 3 that not everytime you remap the fuel or ignition mapping that you get a positive result. Theres alot of hard work we had to do to sort many dramas out... We are talking about highly tuned cars here - not V6 ecotec commodore engines so im prepaired to play around and see what we can make of it

  • 1 month later...

By the way, & to answer previous questions.. Yes its standard Injectors, Yes its standard AFM, No there isnt a fuel reg and the reason the car made that power is simply because of the person that tuned it! Ben is fantastic and worth EVERY penny...

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

    • The rain is the best time to push to the edge of the grip limit. Water lubrication reduces the consumption of rubber without reducing the fun. I take pleasure in driving around the outside of numpties in Audis, WRXs, BRZs, etc, because they get all worried in the wet. They warm up faster than the engine oil does.
    • When they're dead cold, and in the wet, they're not very fun. RE003 are alright, they do harden very quickly and turn into literally $50 Pace tyres.
    • Yeah, I thought that Reedy's video was quite good because he compared old and new (as in, well used and quite new) AD09s, with what is generally considered to be the fast Yokohama in this category (ie, sporty road/track tyres) and a tyre that people might be able to use to extend the comparo out into the space of more expensive European tyres, being the Cup 2. No-one would ever agree that the Cup 2 is a poor tyre - many would suggest that it is close to the very top of the category. And, for them all to come out so close to each other, and for the cheaper tyre in the test to do so well against the others, in some cases being even faster, shows that (good, non-linglong) tyres are reaching a plateau in terms of how good they can get, and they're all sitting on that same plateau. Anyway, on the AD08R, AD09, RS4 that I've had on the car in recent years, I've never had a problem in the cold and wet. SA gets down to 0-10°C in winter. Not so often, but it was only 4°C when I got in the car this morning. Once the tyres are warm (ie, after about 2km), you can start to lay into them. I've never aquaplaned or suffered serious off-corner understeer or anything like that in the wet, that I would not have expected to happen with a more normal tyre. I had some RE003s, and they were shit in the dry, shit in the wet, shit everywhere. I would rate the RS4 and AD0x as being more trustworthy in the wet, once the rubber is warm. Bridgestone should be ashamed of the RE003.
    • This is why I gave the disclaimer about how I drive in the wet which I feel is pretty important. I have heard people think RS4's are horrible in the rain, but I have this feeling they must be driving (or attempting to drive) anywhere close to the grip limit. I legitimately drive at the speed limit/below speed the limit 100% of the time in the rain. More than happy to just commute along at 50kmh behind a train of cars in 5th gear etc. I do agree with you with regards to the temp and the 'quality' of the tyre Dose. Most UHP tyres aren't even up to temperature on the road anyway, even when going mad initial D canyon carving. It would be interesting to see a not-up-to-temp UHP tyre compared against a mere... normal...HP tyre at these temperatures. I don't think you're (or me in this case) is actually picking up grip with an RS4/AD09 on the road relative to something like a RE003 because the RS4/AD09 is not up to temp and the RE003 is closer to it's optimal operating window.
    • Either the bearing has been installed backwards OR the gearbox input shaft bearing is loosey goosey.   When in doubt, just put in a Samsonas in.
×
×
  • Create New...