How far can we advance the timing on the 6th gen safely? From all I read and have been told is to advance until you hear a knocking at idle, then retard 2 degrees. Is this a true statement? Also for those of you who have allready advanced your timing are you advancing both the intake and the exhaust timing. I have read that most people are only advancing the intake cycle and not the exhaust cycle, not on purpose, just because they don't know that they should advance both if you want to see any type of gain from doing it. Also in theory if you advance timing for a high compression and shorter ignition cycle then retarding timing should lessen the compression and lengthen the ignition cycle therefor taking some hp and tq away but improving gas mileage. Faster cycle requires more fuel quicker so longer cycle less fuel more time to ignite. I am asking these questions because I am trying to weigh the benifits before attempting this.

 

It seems you have answered your own question ?

 

I see what you mean but I really didn't mean for it to be that way. I wanted to know for those who have advanced their timing did they see any gains? Did they adjust both the intake and exhaust side? Has anyone retarded the timing? If so did they see any gain in MPG? How much? I am asking these questions because I want to retard my timing for now and when I get my internals done I will be considering advancing the timing if it's worth it.

 

ive heard in the 7th gen forums that advancing the timing 2 degrees for the 09s makes a huge difference in pick up. And they had a cai, and an exhaust... A 2 degree advancing with probably deff be my next mod in the future

 

First of all, to my knowledge, the timing has to be advanced through tuning of the ECU. There are products out there (UPREV) which advance the timing up to 2 degrees, to 17 degrees BTDC, up from 15 degrees BTDC). The best way to advance the timing is to have Tadashi at Technosqure dyno tune and set timing and other fuel parameters.
Regarding exhaust and intake timing: This refers to camshaft timing which is an entirely different issue. I believe there are adjustable cam gears but I dont know too much about their applications on the VQ35 engine. I imagine a Cooks tour of my350z.com and other Z and maybe G websites and forums will yield more information.

 

tuning the ECU for timing is a programming thing. I am referring to changing your TDC, "Top Dead Center", which would be a mechanical change that is permanent until changed back. Basically tricks your ecu to thinking the advance/retard is the TDC. I have done this on older vehicles to include a Datson pickup. Made a huge difference for that little old pickup. The tune would work but I would hate to have to keep sending the ecu to Technosquare for upgrades. Tedious and Downtime. When I am done modding I will concider ECU tune but not quite there yet.

 

I actually did it a couple months ago at the dealer. I can't really tell much difference after doing it. Although a 5 hp gain will probably never show up on the butt dyno. I'm pretty much stock by the way,

 

did it? by it do you mean mechanically adjust the timing? If so how did you do it? Meaning both the intake and exhaust side? Or just the intake side?

 

DeusExMaxima is right on with the difference between ignition timing and valve timing.

Most of the timing changes everyone talks about are changes in ignition timing.

I advanced my ignition timing 2degrees. From 15 BTDC to 17 BTDC

You cannot change the TDC of an engine. Its determined by the crank/rods/pistons.

As far as adjustable cam gears, I'm not too sure how that would react with the variable cam phasing that our engine has.

 

I understand that you can not change the TDC, but you can change adjust the cams to thinking the TDC is normal when you change it. I don't know if you understand what I am saying by this. TDC will never change in an engine but the cycle your cams make can be which is what I am referring to. Ignition timing is different but does work in conjuntion with the Cam timing. All of this is controlled by the ECU and several sensors. If you change the Cam position ahead or behind the ECU will relearn the setup in theory and adjust accordingly. I will find the site that explains it later and post it here.

 

Does this site help?

http://www.vishnutuning.com/evo_cam_gears.htm

Read the summary on the right when you enter the site.

And this forum too:
http://www.my350z.com/forum/engine-a...cam-gears.html

 

Thanx deus I think the 350z forum answered my question. Not possible without investing loads of money for new adjustable cams. At the end of it though one of the guys mentioned that the adjustable cams were the same as the oem and he didn't understand why you would need the adjustable cams.

 

I think its because our cams vary. The question is: What makes our cams vary and can we alter that variation to advance it to our liking? Is it controlled by the ECU? Can we fool the ECU if it is controlled by the ECU?

 

it is controlled by the ecu. http://www.quickbrickmotorsports.com/prod_camtool.html this site is mostly for Volvos, however the cam tool can be used for other applications. It is used only when adjusting while engine is off and then taken off when ready to start engine.

 

from everything I keep reading, the conclusion is that the cams can not be adjusted because they will automatically adjust themselves. In the service manual though it tells you when replacing the timing chain to ensure you align for TDC. So if this is the case then you should be able to advance or retard the timing and it must have some effect on the engine. Seems pretty important and listed in both removal and reinstalling procedures. This is making me wonder if you adjust them, then you should just be moving the spectrum to the right or left. The ECU won't know you made the change, it should just operate on whatever map it has for change in the engine speed and load. So with that being said it will go by how many revolutions the camshaft is spinning and the load on the engine, not on the position of the cam. Now I am not sure how this will effect the Camshaft position sensors. http://www.autoshop101.com/forms/h36.pdf found this interesting reading. I think the only way to get what we are looking for is to get new cams that are designed right, or trick the camshaft position sensors somehow. Even if you were able to manipulate the signal the ECU will adjust accordingly. New Cams seem like the only Viable option. Damn engine is smart. Basically the new cams would have to be spaced differently to help gain/advance the timing. I feel like I learn something new about this damn car everyday. Cams will have to wait till my internal rebuild project.