Knocking

When tuning...you can knock the fuel or something like that right?What is knocking?And how do i do it?

A 10 second search using knock and my user name found this:

http://www.automotiveforums.com/vbulletin/showthread.php?t=164870&highlight=knock

It also on my website... Hope it helps. Just ot clarify, its a bad thing ;)

GSXracer...i dont mean to ask more questions but i need your help.You sound like you what your talking about so please help me.Take a look at this site.

http://www.roadraceengineering.com/newafc.htm

As you can see its the apex'i safc.I like the system.But i have questions on it.They say they set they're low for 30% and high for 80%.What are they talking about...high and low for what?Throttle position?How does that work?Also...the first pic you see shows this...(Hi) 1000 rpm -10%.I dont get that.They also have a pic for the low.It saying.(Lo) 1000 rpm +39%.Is the -10% and +39% the leanness and richness?Or what?You can set the low tuning and high tuning of your tuning.In the pics befor it showed low 1000 rpm and high 1000 rpm.What the diff?Can you help me out with my questions and a all around telling of how air flow works.

On the AFC, there is a high and low "cutoff" point for throttle psotion. There are a high and low "map" as well that corresponds to the settings. So anything below 30% will use the correction you set for the low map, and anything over 80% will use the settings you enter for the "high" map. In betweem the AFC will do some interpolation and the setting applied will be somewehre in between your high and low settings, at the particular rpm you are at. So its a gradual transition from one map to the other, as opposed to a sharp jump from one to the other. I hope that makes sense! :) If not let meknow.

So in summary all the AFC does is intercept the airflow signal to the ECU. It know what rpm you are at. It will apply the correction you set at that rpm, based on what you enter for that rpm, and what your throttle position is. This will alter your airfuel mixture. The advantage to two maps is that you can tune idle and cruise seperately from wide open throttle, which is a good thing.

And feel free to ask questions, by all means. Thats what I'm here for ;)

Ummmm...i dont get what you mean by that.The first part.If i put the gas to the floor...will the low setting jump to the high?How much the throttle is open is the throttle position right.So do i have to tell it to go to the high setting or what?Does it do it by it self?So if i have it set on high my settings wont turn on tell 80%?Is that what your saying?If so...if its on high...what happens to the other 79%?If my settings does work then...does it use the stock settings?Thanks for you help.

Shoot dude...i'm sorry...i get it now...you still can awnser my questions just so that way i know that i'm right.But when you are at lower the 30% in uses my settings and from 30% to 80% it equals out the low and the high.So that way its not a big jump from the two...just as you said.But i still want to know about the throttle position and what that mean?Like if i have the throttle at 30%...that 30% of the way open right?

Oh yea...when i'm setting each rpm...when you have it at lets say...+39 at 1000 rpm.Thats what the MAS see right?And whats like -10?What the +39 mean?Do you get what i'm saying?

Here's a quick MSpaint drawing I just made to help visually see how the "HI" "LOW" settings work on the AFC.
The blue area is designed for daily street driving, the pink area is when you hammer on the gas. You're in the gray area during the time when your foot is mashing the gas. You will probably spend no more than a split second in the gray area in most cases.... well, I do anyways.

http://files.automotiveforums.com/gallery/watermark.php?file=/503/120493AFC.jpg

If anyone sees any discrepencies in this, lemme know. This is just how I've come to understand the HI LOW part of the AFC. The graph is kinda messed up since there are actually 3 variables (throttle %, RPM and correction) but I crunched it down to fit on a X/Y graph.

BTW, How do I get images to show up in my post? instead of using a link

use the and tags around the url. btw you have a lot of nice cars :)

Oh yea...when i'm setting each rpm...when you have it at lets say...+39 at 1000 rpm.Thats what the MAS see right?And whats like -10?What the +39 mean?Do you get what i'm saying?

+39 at 1000rpm is not what the MAS sees. That's what you're telling the ECU sort of. You're telling the ECU to add 39% MORE fuel at 1000 RPM.

Without an AFC, here's what happens:
For example, if the MAS is seeing (X) amount of air at 1000 RPM, the ECU says,
"ok, X amount air is coming? then I'll add (Y) amount of fuel to match the air coming in."

Since the AFC is there here's what happens:

The MAS says "I see (X) amount of air".
The AFC intercepts that message and tells the ECU,
"The MAS sees (X +39) amount of air.)"
The ECU says, "Oh, X+39? Ok, Here's the fuel to match"

That's how we get more fuel to dump into the engine.

In some cases you'll need LESS fuel, so sometimes you'll have a (-) minus setting there. My old set-up wouldn't idle well till I took it down to -8 at 1000 RPM on the "LOW" setting.

Hope this helps.

use the and tags around the url. btw you have a lot of nice cars
thanks

well done rysbrnr. No problems with the picture, and I think thats a good way to show people how it works. ;)