Cam timing chart

[bleunetizen]

I got bored and thought this might bring some good info for those with different cam shafts..

attached chart is a log from cipher when I had my car dyno tuned a while back, we were fiddling with the cam timing for some time and that was the final result we got. But I think there is a bit more power to be had up top with more time spent on the tune.

that is running significantly more advanced cam timing over stock cam timing map. stock cam pulleys are known to be limited at 35degrees but it seems to go a little bit further (37~39, each banks were a little bit different dunno why). we couldn't get any more advance regardless of how much we told the ecu to advance the cam timing, what shows in the chart is a hardware limit of how much it can advance using stock pulleys.

i understand that there are many people with different camshafts in this forum, but they all seem to keep their tunes so secret. I think it will help the whole Z scene to evolve with better information when people starts sharing their maps and settings etc etc..

so here goes my chart. my engine is VQ35DE non revup. tomei 268cams, jwt valve springs, revving to 7200rpm, cheap headers and y pipe with stock cats, fujitsubo catback. it made a significant gain over stock cams.

the chart shows intake cam timing advance for both banks, afm voltage and ignition timing.

any input/info would be great

[Jime]

1. What are you using to adjust cam timing, Osiris?

2. Also, your engine timing is in the mid 20's up to about 3700 then goes up to high 20's to 5000 and then back down to 25 unti it raises again when you hit 6500. Is that where you got the best gains on dyno?

3. I have the V-Manage to adjust my cam timing but I just took it a bit higher than stock, it hits 0 around 5600 I really haven't tried it any higher but I sure will now.

First time I have seen anyone post their timing, good job.
This is where mine is now. a little hard to see using the V-Manage chart but its not much higher than stock. The blue line is the stock cam timing from the Maxima ECU which is much less agressive than the Z. I have a 3.5 swapped into a 95 Maxima using UTEC and V-Manage.

[bleunetizen]

1. Yes, Osiris

2. Yes, we spent some time trying to find the best ignition timing for the engine. We kept the timing down low to minimal as it did not give us any additional power, and the engine was a bit noisier between 5000 and 6500 so we retarded the timing there, and it actually increased the power a little bit.

3. Are you running stock cams or aftermarket?

[Jime]

Originally Posted by bleunetizen

1. Yes, Osiris

2. Yes, we spent some time trying to find the best ignition timing for the engine. We kept the timing down low to minimal as it did not give us any additional power, and the engine was a bit noisier between 5000 and 6500 so we retarded the timing there, and it actually increased the power a little bit.

3. Are you running stock cams or aftermarket?

I am going to do a bit more tuning today on the road so will give the cam timing same as your chart and see if there is any change. Just using utec charts to compare acceleration as well as maf voltage.

Cams are JDM 260's.

[bleunetizen]

Great, will be good to see if its gonna help with your setup.

I use maf voltage as it reflects pretty closely on how my powerband showed up in my dyno chart. 0.1 volt of maf difference resulted as quite a bit of power.

I used to run UTEC in the past which I do not anymore, for some reason it showed me higher maf voltage with UTEC (it went over 4.9 volts!) but maybe its got something to do with my car being jdm, stock ecu didnt like UTEC and threw a CEL even though the car was driving just fine.

look forward to your update

[QuadCam]

Advancing cam timing is for gaining power sooner in the RPM band, not for making power later in the rpm band (higher up.) You'd want to retard the cam timing in the upper rpms (to open the intake valves later) to make more power up high. In the higher rpms, there is so more more psiton speed and port velovity, that opening the intake valve later allows you to take advantage of the momentum of the air entering the chamber.....even as the piston pases BDC, the momentum of the air coming through the heads will still make its way into the cylinder.

Of course, I am speaking in generalities and am not sure of how much the stock ecu cam programs are doing.

[rednezz]

Originally Posted by QuadCam

Advancing cam timing is for gaining power sooner in the RPM band, not for making power later in the rpm band (higher up.)

Depends on the cams...the stock ECU goes to zero cam advance too soon for the Tomei 272 cams. I need to keep around 10 degrees after 6000 rpm and slowly bring it down to about 5 degrees at 6600 rpm where as stock it would be at zero by 6500 rpms.

[QuadCam]

Originally Posted by rednezz

Depends on the cams...the stock ECU goes to zero cam advance too soon for the Tomei 272 cams. I need to keep around 10 degrees after 6000 rpm and slowly bring it down to about 5 degrees at 6600 rpm where as stock it would be at zero by 6500 rpms.

ahhhhh.........I am not aware of how the stock ECU controls the cams.

are the Tomie cams ground around the stock centerlines? or do they have either advance or retard built into the location of the lobes?

[bleunetizen]

i think tomeis got same centerlines.. i didnt measure it carefully but they were very close anyway so yeah.

[Nathan]

Originally Posted by bleunetizen

I got bored and thought this might bring some good info for those with different cam shafts..

attached chart is a log from cipher when I had my car dyno tuned a while back, we were fiddling with the cam timing for some time and that was the final result we got. But I think there is a bit more power to be had up top with more time spent on the tune.

that is running significantly more advanced cam timing over stock cam timing map. stock cam pulleys are known to be limited at 35degrees but it seems to go a little bit further (37~39, each banks were a little bit different dunno why). we couldn't get any more advance regardless of how much we told the ecu to advance the cam timing, what shows in the chart is a hardware limit of how much it can advance using stock pulleys.

i understand that there are many people with different camshafts in this forum, but they all seem to keep their tunes so secret. I think it will help the whole Z scene to evolve with better information when people starts sharing their maps and settings etc etc..

so here goes my chart. my engine is VQ35DE non revup. tomei 268cams, jwt valve springs, revving to 7200rpm, cheap headers and y pipe with stock cats, fujitsubo catback. it made a significant gain over stock cams.

the chart shows intake cam timing advance for both banks, afm voltage and ignition timing.

any input/info would be great

The stock VTC pulley only has a rotation of 20 deg which = 40 at the crank
With a little bit machined of the front face of the vane to allow it to rotate 25 deg, I beleive there could be a fair bit more power to be made in the midrange

[Hal@IP]

Originally Posted by Nathan

The stock VTC pulley only has a rotation of 20 deg which = 40 at the crank
With a little bit machined of the front face of the vane to allow it to rotate 25 deg, I beleive there could be a fair bit more power to be made in the midrange

Nismo offered the same thing: 50deg cam sprockets

[rednezz]

Originally Posted by Nathan

The stock VTC pulley only has a rotation of 20 deg which = 40 at the crank
With a little bit machined of the front face of the vane to allow it to rotate 25 deg, I beleive there could be a fair bit more power to be made in the midrange

Yes I am sure you would make a significant amount of power. I picked up around 10+ rwhp in the midrange just going from 36 degress to the maximum of 40 degrees in the midrange.

Can you explain further where you machine? Did you machine the outer housing or the center assembly that rotates?

[Nathan]

Originally Posted by rednezz

Yes I am sure you would make a significant amount of power. I picked up around 10+ rwhp in the midrange just going from 36 degress to the maximum of 40 degrees in the midrange.

Can you explain further where you machine? Did you machine the outer housing or the center assembly that rotates?

I have not done any modifications to the VTC pulleys.
When my motor was apart close to three years ago I was thinking of doing something, but at that time I had no way of controlling them short of a very expensive MoTec. There is no one in Oz that could reflash & Haltech was still 2 years away.
If you look at the photo, the part that needs machining is on the rotating vane where I have placed the tip of the pen. Just a small amount here would allow another 5 deg.
The other photo shows the centre vane in the retarded position & you can see some black dots under the protractor that there is only 20 deg of rotation available.
At the time I was thinking of doing it, I contacted Ritchi (350Z Lover) to see if his mechanic could take the front plate off his Nismo pulley & take a photo so I could see what Nismo had done too them, but his motor was by then reassembled.
I also contacted Adam from Z1 to see if he would do the same to his Nismo pullys, but he declined as they were new product still in there box for sale.
I nearly went ahead but without control I was concerned that the extra advance may throw a CEL not to mention possible valve to piston clearance as I am using 12mm lift & 290 duration Inlet cams.

[QuadCam]

good stuff Nathan!

conversely, it appears that there's room to machine off the other end so that you could retard the cam timing slightly for more top end power.

Jeremy Tibbs and I took one of these apart awhile back and I recall all sort of springs and sort popping out of the pulley. Once apart, it might be quite a chore to get it all back together.........correctly.

[Nathan]

Originally Posted by QuadCam

good stuff Nathan!

conversely, it appears that there's room to machine off the other end so that you could retard the cam timing slightly for more top end power.

Jeremy Tibbs and I took one of these apart awhile back and I recall all sort of springs and sort popping out of the pulley. Once apart, it might be quite a chore to get it all back together.........correctly.

It's very simple to pull apart, the vane just comes out complete
The spring & seat not showen in my photo,is used to lock the vane in the retard position so that there is no movement when the motor is cranking over on start up & no oil pressure.
As soon as there is oil pressure the the plastic lock valve is lifted away allowing the vane to turn if the ECU so directs.
There is no need to have any more retard as the fully retarded inlet cam is there for emissions & idle (no overlap)

[rednezz]

Nathan, thanks for the info!!!! I think I'm going to order me a extra set of VTC pullies and give it a try.

[Z1 Performance]

yep these are very easy to take apart.

[Nathan]

Originally Posted by rednezz

Nathan, thanks for the info!!!! I think I'm going to order me a extra set of VTC pullies and give it a try.

If you are going to purchase new pulleys why not save yourself a lot of time & trouble & just get the Nismo set.
If you do, take off the front plate & take a photo.
If the Nismo ones are manufactured as I suspect, that is a vane with that extra few mm missing off the leading edge, there could be a good market in exchange modified pulley sets.

[QuadCam]

I just took one of mine apart today. I think I know what it was that fell out last time............it was all the little "scrapers." this time, I was very carefull to take it apart and examine.

I am still not sure how exactly the motion is controlled. it seems more like it would be either fully advanced or not.

What controls the amount of motion on the phasers? Is it the oil pressure that rises as rpms rise, or is it just the pulsing of the oil contorl solenoid. Either way, I'm not picking up on it yet........I think I need to stare at it longer!!!

[Nathan]

Originally Posted by QuadCam

I just took one of mine apart today. I think I know what it was that fell out last time............it was all the little "scrapers." this time, I was very carefull to take it apart and examine.

I am still not sure how exactly the motion is controlled. it seems more like it would be either fully advanced or not.

What controls the amount of motion on the phasers? Is it the oil pressure that rises as rpms rise, or is it just the pulsing of the oil contorl solenoid. Either way, I'm not picking up on it yet........I think I need to stare at it longer!!!

There is a good general description on how they work in the Workshop manual.Maybe someone can post it up.
Basically the oil pressure is = each side of the vane, when the solenoid receives a pulse code from the ECU more oil is directed to 1 side of the vane & the other side has it's pressure released so it will now turn.
Say if it only has to turn 10 deg, once the ECU has received the feedback from the cam angle sensor that this has been achieved the solenoid will be instructed to equalise the pressure again.