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-   -   AFC - Lo Throttle Knocking? (https://www.homemadeturbo.com/engine-management-10/afc-lo-throttle-knocking-4329/)

Chacko Apr 28, 2003 03:10 AM

AFC - Lo Throttle Knocking?
 
I'm just curious if anyone out there has experienced any knocking under very lo throttle (like 20-30%) at around the 2-4k RPM range... I'm only pushing about 2 psi and spiking to 3 in this range... but every now and then I swear to god I can hear a little pinging.

Anyone else have this problem? no its not intercooled, I'm using the water injection but it only kicks on at 4 psi otherwise I'd waste to much water. This may be a reason to use an intercooler on top of water injection ;)

fork Apr 28, 2003 11:12 AM

Re:AFC - Lo Throttle Knocking?
 
If your using 450cc injectors and the hack it's probably because this setup advances your timing. also a hotter intake charge (no intercooler) can cause detonation. I'd say retard the timing or get an intercooler or both. If your worried about cash pick up an eclipse or saab intercooler from a boneyard. or a starion one if you could find one, but I sure can't.

gtcali Apr 29, 2003 06:48 PM

Re:AFC - Lo Throttle Knocking?
 
Whoa - Maybe this is similar.

I'm getting my car ready to be turboed (its ready).

Anyways. A first I installed the vafc just for a vtec switch. Stock injectors. Everything at 0%. Everything is fine.

I figure I'm close to putting the turbo on so I install 450 injectors (no turbo yet). Now I'm knocking just like you said. Between 2-4k. I thought maybe I just started noticing the knock since I installed something new and I have forged pistons.


Dr.Boost Apr 29, 2003 07:04 PM

Re:AFC - Lo Throttle Knocking?
 
What is your timing set at?
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fork Apr 30, 2003 11:00 AM

Re:AFC - Lo Throttle Knocking?
 
Read the post afc advanceing my timing. When you use the afc hack and 450cc injectors when you lean out the afc this also advances your timing so retard the timing at the distributor.

gtcali Apr 30, 2003 12:25 PM

Re:AFC - Lo Throttle Knocking?
 
Fork, OK, I thought you meant under boost. I'm currently not boosted. I didn't however check my timing. I'll check it tonite. Makes sense now.

Chacko Apr 30, 2003 02:49 PM

Re:AFC - Lo Throttle Knocking?
 
I am fully retarded in timing. Its not a cooling issue I don't think, because if I drive under full throttle or even less throttle there is no problem. Its only around the 30-40% and its a very light knocking...
I think one injector may not be flowing as well as the others.

Chacko May 2, 2003 12:43 AM

Re:AFC - Lo Throttle Knocking?
 
Nope its not the flow is it possible that the AFC Hack is just advancing my timing to much for low throttle driving?
What chip can I get to get around this crap?

Chacko May 3, 2003 12:38 AM

Re:AFC - Lo Throttle Knocking?
 
Someone use their infinite wisdom to aid chacko!

Semnos May 4, 2003 08:29 AM

Re:AFC - Lo Throttle Knocking?
 
This has already been talked about over and over again.
It's the 10+ degree in timing advance that the AFC hack has at low boost 1-4 psi.
After that the timing goes back to normal. There is no way to retard it that much unless you chip your ECU.
If you're OBD1 you have to get Uber's chip if you OBD0 you can download GeorgesBINHAck from the PGMFI Forum and burn the chip yourself.
With this you don't need the AFC anymore, because you can tune your fuel delivery with Ghettodyne.


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