# advancing timing



## Sergei_dekker (Jun 4, 2005)

guy I heard of a few fellas talking about advancing timing for their engines...how do u do that? do u have to change cams etc?


----------



## ValBoo (May 19, 2003)

*A.T.*

Sergei,

Terranismo gave me a few tips how to go about this and I had it done at a dealership where you can have a good rapport with the mechanics themselves.

If you decide to do it it will be advisable to run with 91 octane minimum.

Please read the attached link:
http://www.b15sentra.net/forums/showthread.php?s=&threadid=65279 

BTW it is not one of the most noticeable improvements, so don't expect too much.


----------



## Sergei_dekker (Jun 4, 2005)

ValBoo said:


> Sergei,
> 
> Terranismo gave me a few tips how to go about this and I had it done at a dealership where you can have a good rapport with the mechanics themselves.
> 
> ...


not aq problem since i use 98 octane all the time


----------



## manuelga (Dec 14, 2003)

ValBoo said:


> BTW it is not one of the most noticeable improvements, so don't expect too much.


QR25 computers adjust timing way too much, because knock sensor (that thing is ultra sensitive), I've seing at Sport Compact Cars how to isolate knock sensor & turning the engine a very stable one.


----------



## ValBoo (May 19, 2003)

manuelga said:


> QR25 computers adjust timing way too much, because knock sensor (that thing is ultra sensitive), I've seing at Sport Compact Cars how to isolate knock sensor & turning the engine a very stable one.


From what I read and discussed...
Lets not confuse things: when we talk about setting more timing advance it is only a couple of degrees of the basic timing which is noticeable when you then get in the car and drive normally.

Your knock sensor (which will retard timing) only kicks in when it hears knocking (or lots of vibration from the engine e.g.: high Rev with BSR mod).
True enough the knock sensor on qr25de 2002 and 2003 was over sensitive, BUT from recent reports Nissan had corrected the problem on the 2004 and 2005. So for later models moving the knock sensor may be an unnecessary mod (and may be risky IF in fact your engine starts knocking).

just reporting my findings...

also see thins nice link:
http://auto.howstuffworks.com/engine3.htm


----------



## thetimster (May 6, 2005)

*Moving KS and Advancing Timing: Hand-in-hand!!*

This is how I understand things... advancing timing can cause the air:fuel ratio to favor knocking. Therefore advancing timing can potentially cause more knocks and if so, it will end up robbing you of power rather than adding to it, especially if it is advanced too aggressively. When the KS is activated, timing is actually retarded.

On a related point, the KS of the QR25DE engine is located in an area that has a lot of vibration. Since the stroke of the engine is long (which is how the QR20DE engine became a higher displacement QR25DE in the first place... by lengthening the stroke rather than increasing the bore), the engine has a higher tendency to vibrate. This vibration and engine movement in general CAN be sensed as a knock by the KS thus falsely robbing the engine of power. 

Since the KS is ALREADY too sensitive, you don't want to advance timing without first moving it. In fact, based on posts in other forums, KS relocation alone seems to free of some extra HP. 

Now even if you use higher than 91 octane gas and prevent detonation, advancing timing alone can still activate the KS because you will have more aggressive combustion with advancing timing and thus more vibration will be produced which CAN be falsely sensed as a knock. 

Since all of us are using more than 91 octane gas anyway, there theoretically SHOULD be little to no knocks, so the KS can be grounded (a la Terranismo). Once that is done, then and ONLY then would advancing timing really help.

Anyway, here is a little info on relocating the KS as well...

http://www.nissanperformancemag.com/december02/knock_sensor/


----------



## ValBoo (May 19, 2003)

*Knock-knock !*

Tim,

some good points...

The idea that I don't like about defeating the knock sensor altogether is that it is there for protection (I know.. I know.. it shouldn't be a problem with higher octane, but still, knocking will not only rob you of power but it will damage your engine).

Now if one could only get a knock sensor "just perfect" then that would be great!

And as I said: true it was proven to be too sensitive on 02-03, BUT it was found to be very good (not too sensitive) on 04-05 model years.

since you mentioned this before:
I already have my SAFC II, and have already got all connections points to the ECU ready. I will then have tuned by an expert here in Montreal.

*And after that, hopefully, I can report back also about the sensitivity of the knock sensor in my 2005 X-trail*. I will let you guys know my findings. (I will also try to post pictures about the installation and wiring connections if you are interested in doing it yourselves. 

Also had my air fuel ratio evaluated before purchasing my SAFC II...
It was found to be running "PIG RICH" about 11 to 11.5 versus a better ratio of 13.5.


----------



## thetimster (May 6, 2005)

Valboo... you are moving too fast! SAFC-II already in!! YES, YES! Please post pics and give advice on the SAFC-II installation. I am curious to find out WHERE in the vehicle you installed it. 

11.5!! Yes indeed that is, as you put it, pig rich. 13.5 might be a tad too "poor" though, don't you think? Most forums seem to suggest 13 to 13.2.

Let us know how it goes. My AFC should be arriving next week. But I don't want to install it until AFTER my header installation is completed. Unfortunately, that will be another month or so. As I said in other posts... no X-trail parts here in the Philippines!!!!  

And oh yeah... to stay within topic... you are absolutely right about certain DISadvantages to moving the KS. Just like the speeding thread though, this is a forum for discussion and our talking about it will not make us responsible for any engine damage anyone might encounter from trying it!  

I for one have decided to do it. As you mentioned in your post, it IS a problem in '03... which is the year model of my X. So it will certainly help to try it in mine.

Thanks Valboo!


----------



## ValBoo (May 19, 2003)

Tim,

my SAFC is located in the hidden compartment (the one with the two sliding doors) below the radio (I can't tell from your pictures if you have the same layout as canadian version). I'll post when I get my pics (still no digital camera  )

You are right, yes, I'll see about the ratio, probably my "Chemist" will decide, (while HP is nice, I might get better torque at 12.8)

AH now I get it... I was sure you had a 2005 edition. Sorry ! go ahead move that knock sensor 

Later,


----------



## thetimster (May 6, 2005)

Advancing timing shouldn't take long, should it? If I can (finally) work on the KS this weekend, I'm hoping to do the timing this coming week.

I'll be sure to let you all know how it goes, whether it changes anything perceptibly, or (hopefully not) whether it completely shuts down my X!


----------



## ValBoo (May 19, 2003)

Really quick!
When the technician actually started with my car, it took him a whole 5 minutes to do the ta. 
Tim, when you get it done could you report back on what your figures were? (mine was dead on -15 deg BTDC as per specification, and was put to -17 deg).
But some people report their initial setting figures at -14 or -13 BTDC !

I guess in this case it does not really matter which you do first KS or TA.
Enjoy your mod!


----------



## thetimster (May 6, 2005)

Yes ValBoo... I will be sure to do report what my timing is. Per specifications, mine is also SUPPOSED to be at -15 (as will almost all other QR25DE engines I gues).

I have all the stuff I need (or at least I think I will need) for relocating the KS. I will try to do this tomorrow and will try to get some pics. Once my hands are dirty I don't know how good the pictures will be but will try my best to be thorough. It will remain to be seen whether it is as easy as they make it look on that webpage I referenced to. 

Then Wednesday I'll try to see if my timing can be advanced.

Now I'm excited!


----------



## Sergei_dekker (Jun 4, 2005)

well mine is 17BDTC already...so does that means its already advanced??? and whats the highest u can go??? is 19 okay?


----------



## thetimster (May 6, 2005)

We're now :topic: but I guess its still somewhat related...

ValBoo, here is a pic of my console. It doesn't sound like we have the same one. So I still need to search for a place to put my SAFC when it arrives.


But you can help me another way though... Who installed your SAFC for you? If you did it yourself, what wires did you connect it to? Do you have a code for our wires? If you DO have pics of the install, it will be extremely helpful to see it. Maybe in a separate "How to" thread?

Thanks!!


----------



## ValBoo (May 19, 2003)

I installed it myself.

I have all the wire code numbers and colors (for our canadian version) and it shouldn't change too much (still would be nice if you can get your hands on an ESM for your version to double check wire numbers)

No pics yet but I will get them eventually and make an info post.
But lets close this now since :topic: and start a new thread.

Later,


----------



## Sergei_dekker (Jun 4, 2005)

dude can anyone answer my qn?? is 17BDTC okay? can it be advanced to 19?


----------



## ValBoo (May 19, 2003)

Here are some facts based on a few QR25DE engines in SpecV 

Just like X-Trail the "specification" for basic timing advance is 15 BTDC.
These engines have been found to be set at 15, 14 and 13 BTDC.
Further advancing basic timing a couple of degrees is ok (bringing it to 17 BTDC). *Again from experience it seems that the ECU will not accept input timing more advanced than 17 BTDC*.

(however, Terranismo had proven this wrong since he told me his total advance was now set at 18 BTDC)

I would not go any further than the above, if the ECU will even let you get to 18 at all (I think you are already maxed out at 17 BTDC, as I am)


I also see you did not bother reading the "linked post" I provided you in my first reply, you would have found the same explanation!

Later,




Sergei_dekker said:


> dude can anyone answer my qn?? is 17BDTC okay? can it be advanced to 19?


----------



## thetimster (May 6, 2005)

I had my timing advanced today. ValBoo... reporting figures as promised.

Mine was dead on 15 as well. It could only be advanced 2 degrees. It wouldn't take 18. So now I am also at 17.

Haven't had a chance to really drive it with 17. But with the computer left on, I revved the engine a bit and it hit a maximum of 18. So that's good... revving it up didn't retard timing but actually made it better. During idling, it would read as low as 13.

Hope others report their experiences, too.

And oh yeah... it was a 2-minute job. The guy plugged in the computer (to a slot underneath the steering wheel) with the engine running and all accessories off. Took a reading, adjusted the timing and that was it!


----------



## ValBoo (May 19, 2003)

Thats great Tim!

I am glad to see that at least the numbers are consistent! Thanks for reporting 

( Sergei: I hope you are reading this  )

Now when you get a chance to drive around you will get to experience the little added punch.


----------



## thetimster (May 6, 2005)

This is the picture of the computer console after correction. As you can see, it was corrected by 2 degrees and is now 17.


I took the X out this afternoon. There IS some punch!!.. particularly when you want a little sudden burst of speed. I think despite the fact that the increments are in small amounts, they are really perceptible. First a little boost with the drop-in AF, then some more with moving the KS, and now even more with advancing timing. You picked the right word that I was searching for to describe it ValBoo... it is punch!  :thumbup:  :cheers:


----------



## Sergei_dekker (Jun 4, 2005)

what octane for petrol are you using???


----------



## thetimster (May 6, 2005)

Using 95 minimum octane rating fuel, Sergei.

If you are already running 17BDTC, I don't know if you can still advance past that. If you pop your hood and look at the specs written there, I'd be willing to bet you would have 15 as recommended. If so, you might not be able to get it to 18, much less 19. If you do try to do it, I'd like to know if you were successful... and whether the change results in improvement of your perception of your car's handling after that.


----------



## mamalik1 (Jul 4, 2009)

Hi, 
does anyone know where I can get a timing diagram for my 2003 nissan primera 2.0 petrol, enging QR20DE


----------

