First thing is first I installed some HKS 272's Friday and the car pulled very different meant that in a good way, Saturday I decided I would put in the Greddy upper intercooler piping but before I filled up some gas and did not notice any difference. Later in the day after installing the piping I carried the car for a spin check the wideband setting and saw the AFR's off the scale 10.0 where it was normally 11.5 fustrated I checked over the piping and said flick that maybe I hitting a different area on the map so I retuned and the car felt weak. Sunday I checked over the piping again and went for a spin it was now lean I reloaded my previous map and the afr's were right back on target where I had before 11.5 however I am now getting plenty knock like 13 counts and the car is falling flat on its face I cannot understand what the frick is going on. My main question is after installing 272's do you have to retard some ign timing? my cam settings are -4 -1.

 

I see increased knock activity too with my cams. I think it has to do with lifter tick.

 

ok I notice something in the logs just now where I normally see 100% in octane its showing up 98.4% now where I live they claim we get 95ron at the pump would 1.6% drop in octane cause this? don't know if I working it out correct but it would mean that instead of 95 I would be around 93ron.

 

If you installed piping and your AFR's went really rich you most likely have a boost leak.

This would also causing knock as well. Turbo over spins to keep up and you get hot air.

 

I agree. It's almost impossible to find a pesky leak without a compressor.

 

I just installed my HKS 272's not to long ago and I am very pleased with the results! I'm curious as to the gains or losses from installing them -4-1? I put mine in straight up and have had great results.

I also had a slight boost leak when I went with a different pipe setup and once I got that fixed and my latencies dialed in a little better all is good now!

Josh

 

Octane 100% is not telling the ron/octane fuel you were using. It should be 100% until you hit knock, the value will reduce... for example if you hit 13 knock, octane might drop to 99.6%

 

Your theory did not apply to my situation I got a lab to test the gas and it did show water in it therefore resulting in lower octane I have attached a log where you could see even on idle with no load the octane is 98%.

update on this thread my car is running stronger then ever at same boost loads since I filled at a different service station.

 

It is a learned value, it probably had knock before the idle situation.

octane % is not measuring actual octane rating whatsoever.