Mods are:
No cats
HKS SAFR
Upgraded fuel pump
Open Air Intake
450cc injectors
boost set at .95 bar

Just installed a set of 450s in my car because one of my old stock injectors was filling up my oil with gas due to it being stock on or dripping. I have it leaned out to about -15% across the rpm range. It should be more than enough fuel since it should be leaned out at around -20% for those injectors. Since I installed the injectors I get constant knock if I go anything past 50% throttle, so I havent even attempted to go WOT. Here is the datalog.

Wouldn't it be nice if all you had to do was set everything at an even % across the board and forget about it? Unfortunately, that's never the case.

The ECU is telling you it wants less feul. I'd start by leaning it out 2-3% every 1000rpms starting at 3K. .94 o2s are still kinda rich. Yes, running too rich will also give you knock.

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06 Blue EVO 9

~~Insert dumb question here~~

How is it that running to rich will also cause ka-nock?

Is it igniting early because of the excess fuel being compressed?

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Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!

When you put it that way, my last statement is misleading. You can't burn a piston from having a rich fuel mixure because not all the fuel would burn during combustion. It would actually cool the cylinder and help prevent knock.

However, I've found that the answer for tuning out knock in our motors is not to simply dump a crap load of feul in because that puts the ECU into a different timing map which then creates the knock. I believe that to be the case here. It's easy to find out.

If that's not it, we need to confirm if the knock is "real" or not. Mike, do you have a way of getting any race feul?

So what your saying is that the oxygen sensors are seeing a "way to rich" setting and so the ECU is switching to a leaner fuel map and giving it timing advance, which is causing the knock by making the car lean itself out to far?

So by putting race fuel in the car you will have approximatly the same O2 readings, so the car will attempt to do the same fix, but the higher octane will lower the ka-nock count. And that will tell us if the car is counting it's ka-nock correctly? - because we will se a lower count...

Where as if it has the same ka-nock count with race fuel we know that the car is seeing a different problem.

Anywhere close to the correct line of thought?

_________________
Bad decisions make good stories.
Look at it! LOOK AT MY @SS AND TELL ME IT'S PRETTY!

Doesn't work that way. The ECU is seeing the altered signal from the AFR and is applying the maps for that hertz amount. The o2 trims will show a rich condition and the ECU will compensate for that a little. The problem might be the timing advance for that level. That's what leaning it out will tell us.

As for race feul, an engine can only stand so much boost, spark advance, compression ratio, and mixture leanness before it begins to detonate. If the knock is indeed "real", adding race feul will show this to be the case if it goes away. It could be something like excess carbon build-up in the heads, bad gas, faulty injectors/ignition, or.... could be lots of things.

If the knock does not go away, then we know it's something with the mechanics of the motor like a bad/loose knock sensor, worn motor mounts, or any of the other 100's of causes of false knock.

Greg has earned a great reputation for his knowledge, and I'd like to just back him totally on his thoughts here. I talk to people who routinely try to drown knock with fuel (not necessarily what you're doing), and can't understand why their car isn't fast. The key for me was to chase after a particular A/F ratio and try to hit it throughout the RPM band. Sometimes you'll get a little lean and find knock, but the "race gas" test is the best way to determine if pre-ignition is the cause of the knock readings.

Good luck, I think Greg has given some great info here.

Matt

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1993 Sandstone Gray Metallic VR-4 (1 of 56)
11.77@122
11.76@119

Well got my cleaned injectors back. They all had good flow #s but 3 of the end caps were broken. He replaceds those for me, but dont know if those affect spray patterns or not, but it guess they would becuase it would cause a huge boost leak right next to the spray. Well anyways, got a new datalogger and did some logging. No knock at all no matter how much I beat on it. So.....problem solved.

Glad to hear it!

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06 Blue EVO 9