http://www.gadgetonline.com/u-tune-aic.pdf

Explanation starts on page 13.

I'm a little fuzzy on how it actually works in regards to advance/retard. All I know is you're supposed to get it back to where it was stock, and for me it was 20.5 advanced at WOT and I had to put a 9 in the 7 psi column to accomplish that. Now my OBDII BR-3 shows 20.5 again at WOT.

 

Oh thank you very much, that is a much better wrire-up than the original u-tune guide I have here:
http://www.gadgetonline.com/U-Tune.pdf

I see where the confusion comes from now, see this quote from Gadget:

In other words the timing has been retarded, but the ECU doesn't know it, so of course the OBDII scan tool can't report it correctly either lol. That clears a lot up with me anyway.

The reason you want to get what the ECU is reporting back to 20 deg advanced is because that puts you back into the middle of the adjustment range or at least where the Toyota engineers had it to begin with.

I also see Gadget recommends the knocklite in this write-up.

If you needed 9 deg of retard with the stock pulley I bet I need to go up to about 12 with my 2.1" pulley. OMG no wonder my knocklite keeps blinking at me with only 6 degs of retard. I hope that auto fill function can get me around the flashing CEL.

 

If the OBDII doesn't know what the timing is, then why does it report 20.5 for me now after adding in 9 degrees? Before it reported 11.5. That's what is confusing me. I didn't think it'd know either, but it does in my case.

Good luck. Let me know how you make out.

How hard is the knock lite to install?

 

Thanks for the explanation Speedy. I am working on retarding out some knock around 3500 rpm too. One thing though, I am using a different unit to control timing (MAPECU2). So when using the RA4 -does a positive value (in your case "7") - actually mean you are pulling 7 degrees? If you are pulling 7 degrees, this then allows the stock ecu to advance back up to 20 degrees where it's happy right? Just trying to get a grasp of it all.

Thanks!

Gregg

 

It's not too hard to install, about like installing an FTC unit.

If I understand it correctly the ECU reports what it "thinks" its setting the timing at, but in reality, the piggy back is intercepting the signal and delaying it. Of course the OBDII just reports what the ECU tells it. I can't explain your stats.

 

That's my understanding. Putting a "7" in retards the ignition by 7 degrees.

Adding boost to an engine makes the combustion process more efficient. Stock ECUs aren't programmed for this more efficient combustion and when they sense knock they reduce the amount of timing advance. However there is only so much range in the stock ECU for timing adjustment. The goal to using a piggyback to help control the timing is to add back in some retard restoring the stock ECU to the range it was programmed to work at from the factory.

That's how I'm seeing it.

 

I think you're right. Stock the ECU wanted 20.5 degrees of advance. I stuffed in 7 psi of boost which dropped the knock threshold to 11.5 degrees of advance. This was probably the max adjustment the ECU had available to it. I then pulled 9 degrees of timing, which changed when the engine might knock pushing it back to near stock levels, so the ECU now goes back to 20.5 degrees of advance.

I think that's correct.

 

I put the URD 2.2" pulley on tonight. WOW huge difference. I didn't think it would be that much, but you get into boost with a lot less throttle. According to my Autometer Mechanical boost gauge I'm seeing 9.5 lbs at full throttle.

Also, I can spin the tires all day now. I left two piles of black powder from the tires (thanks to the TrueTrac) doing a little brake stand testing.

My tune is pretty close. The 2.2 leaned me out to just about a perfect ratio. I need to do some more thorough logging and get somebody to drive the 4Runner while I look at the map.

I'm definitely going to need a tranny cooler. That's next on the list.

 

Not to mention the ipt valve body - thats been on my list for a while.

 

That's on the list as well. I'm going to research that a little more. I've heard some complain of the shifting being harsh after the IPT valve body work. I do not want that.

I've also checked with a local transmission shop who says $600 for a valve body job is WAY over priced. This shop does all the local mail trucks which use the same tranny as our 4Runners and they do them for $200 - $300. I'm gonna have them take a look at mine to see what they think.

 

Tell them that if they know what they're doing, I'm in for a modification too. I'm having serious trouble coming up with $700 for a VB mod while saving for a house and stuff...

 

Will do. I'm going to go down and talk to them in a week or so.

 

I spent a lot of the weekend working on tuning and I've got a good start.

How are you guys listening for ping? I'm not getting any in the high gear low rpm area. It's very hard to tell if I'm getting any in the upper RPMs as the wind noise and intake noise drown out everything.

I'm hearing something that "could" be ping, but I can't tell if it's the SC, intake, belts, etc. It has a whistling noise but it's to a very distinct frequency like a fast ticking sound when I really get into the throttle.

Edit...Here's a screen shot of my timing map...

 

mt_goat got a "knock sensor light" that he is able to use to tap into the factory knock sensor. Seems like that might be the route I wish to go.

 

Speedy how far in the rpm range did you retard the timing? all the way down through all the rpm ranges? or just to like 3500 - 4000 rpm???

 

Look 4-5 posts up and you'll see a screen shot of my timing map. Gadget thinks that's A LOT of retard so I'm gonna do some real work on it this weekend to make sure it's right.

I've been doing the driving AND tuning which is very difficult as you can imagine. I'm gonna have someone else drive while I tune this weekend to make sure I have this correct.

 

go online and get a free program called camstudio. it records your windows screen. I put the obd and r4 tuning software in it and launch the recorder. you can drive and log data for closed loop.

 

That's interesting, do you mean the free 30 day trial?

 

http://www.camstudio.org/

Looks totally free to me. I'm gonna try it out.

 

It works great for a free prog . I record all of my tuning .