Let me see if I can give you guys enough info to help me figure this out. Mods are in my sig.

It seems the knock on my car is not improving. I lowered the boost and added 10% of fuel with knock still present.

It was tuned at 26 psi on 93 pump and methanol with "some" spikes of knock in the 3-3.5 range on that tune.

On my last few logs it showed 4-4.2 volts of knock in about 5 different rpm ranges. I added 10% to the fuel and it lowered "some" of the knock down to 3-3.5 volts, but I still have one or two spikes to 4 volts. A/F's are in the 11.5-12 range in low rpm and once the methanol kit hits the a/f's are in the 11-10.8 range.

Boost hits 26 psi at 4500 rpms and ends up 24 psi at redline.

I even added 1 1/2 gallons of C16 to about 3 gallons of 93 and it is still knocking above 3 volts.

What the heck could be causing this? Could this be a boost leak getting worse?

The car has also had a "hiccup" issue 500-700 miles after changing out the plugs. I just changed the plugs from BR8ES back to BR7ES to see if this remedies the situation.

I have tried gapping the plugs to .026, .024, .022, and .020 and they seem to work good for a while "at any gap", but then it starts doing it again. When I remove the plugs they look good. No detonation at all.

Maybe blowing out the spark because the gap was too small? I am using the HKS DLI 2.

I will be doing a boost leak test and compression test this upcoming week, but I was hoping somebody might have an idea as to what is causing this.

 

Thats a lot of knock. Im not sure what youve changed lately in terms of mods but Id try and take a step back.

 

Post an internal log on the AEM forum.

 

This is a very simplistic response, but could it be that your timing is just too aggressive for the octane/boost you are running? If adding fuel reduces it, it sounds like real knock rather than something else triggering the knock sensor (like valvetrain noise).

 

The timing starts at 2 degs and ramps up to about 8 degs by 7400 rpms. Actually not much timing at all.

 

Anytime you see knock in your logs you should always yank the timing and lower boost first to see if it changes the outcome. It is the best way to help reduce your chances of engine damage. Remove ign timing at the load points that seem to get loud and re-log and look for changes. Continue to go lower until things clear up if possible.

8Deg isn't that much at 7000+rpm at 24psi but there could be several other factors causing your knock (fuel, alky or alky jet problem, headgasket, or others). 3+volts is too high on a stock motor too continue to run safely.

AF's should be 11.0-11.5 once fully spooled on alky or pump (just like you stated above should be fine) Plugs gapped to .024-.022 should be fine.

 

Not running enough timing can cause knock and hiccuping, backfiring as well. Another shop on here "tuned" an AEM EMS for a customer and it was doing exactly what you're talking about. He had timing from 3 degrees to 8 degrees at 7000 rpm. After bumping up the timing to something more resonable the car ran like a champ.

You need to be in the right ballpark with ignition advance. Too much or too little will both cause problems.


Since you mentioned a potential boost leak I'd definitely check that out too. Do you have an EGT gauge? I bet your temps are a bit scary with timing so low.

-Mike

 

How come these people are running such little timing. Im runnin 17 degrees timing at 7300rpm?

I saw a guy on a thread with the 20G saying he was only running 8degrees at 7000rpm? Does it have to do with the turbo? I know my friend is running 17+ above 7000rpm too.
???? Im confused!

 

You can't compare AEM timing numbers to timing numbers from the stock ECU, or a stock ECU with a piggyback. BTW, 17 degrees at 7300 is actually on the low side for the stock computer. I think most people are at 20+ in that RPM range on pump with a Dynoflash. Then again, there's more than one way to skin a cat, so you may have a leaner, higher boost tune with more conservative timing. Whatever works on your car...

 

Oh ok thanks. I thought no matter what tuning device timing was the same. Yeah my timing max goes to 18 at about 7500rpm. However, car is running great and is extremely strong!

 

If they're different then timing wasn't synched properly.

 

The AEM will NOT run the same amount of ign timing compaired to what the stock ECU. Even with the ign timing synced properly, no one that I know of has rock hard evidence as off why but I believe it has somthing to do with the Stock ECU showing its base ign timing table before trims are involved compaired to the AEM showing the raw calcuated amount. (This I don't know for sure, just a theory).

 

Just for reference, I put in some C16 the other day and made some pulls and the only "major" difference I noticed was even if it was still knocking, it was a skinnier spike.


Example: Instead of the spike being between 6400 and 6700 it is now 6500-6600, so not over a wider rpm range. Does this make sense?


----__
--- l----l----------------------------^
--_l----l_ --------------------------l l
--l--------l--------------------------l l
_l---------l__now its like this _l l_ It went from wide to skinny, but still a spike
nonetheless.


Don't make fun of my graph either.

 

^^^Anybody?

 

I never agreed with your theory of the RnR exhaust manifold causing the knock, but have you eliminated that as a possibility in your troubleshooting?