dovla

With good 93-octane gasoline, 2 degrees should not be an issue, and there is a knock sensor there. With FI would be different story. But once with half a tank of 91-octane (Sunoco mistake) I received P0303 on the road and once with bad 93-octane (corn?) I had P0300 while on Pocono track. So now that you have Cipher watch out which one of the California finest gasoline you will be pouring into your tank

Cats will probably lean you out more than plenum.

Wired 24/7

iTrader: (2)

We only get 91oct around here. And 100, but that's like $5.75/gallon. You lucky bastid, with the 93

I have some updates with cipher.....

I reset the fuel maps and did some more runs. Next step: install cats (hopefully this week) and do some more runs. Then, tune.

It looks like the reset did not really touch any of the open-loop fueling (after 4k rpm), but as you can see the timing is different by about 1 degree and it's really lean early on in the closed loop part.

Silo

iTrader: (1)

I find it strange that timing goes up at over 6k rpm... shouldn't it be going down? And then I remember the issue with non-revup engines using the MREV2 + 5/16 spacer when the power fell below stock - incidentally also at >6k rpm. Anyone care to comment?

dovla

Wired 24/7, you keep repeating about close-loop part and open-loop part, both at WOT, I assume. Is that a fact? Ever since I get the Cipher I was suspecting this and it was only explanation I have why would ECU cut the fuel at ~3450 rpm on my second chart in post #15. Is 4K rpm ECU border of closed/open loop at WOT, as per cams curve? None of this is in the service manual and contradicts with what is written about WOT and open loop there.

All intake cams logs that I have seen, angle went up to 37-38 degrees at 2K rpm, stayed there until 4K rpm and then gradually fall down to –2 degrees at 6K rpm and then stayed there until rev. limit. Shouldn’t ideal intake cams curve be like a straight line from 45 (?) degrees at 2K rpm falling down to -2 degrees at rev. limit?


Silo, do I remember correctly, you have NA Z with 300+ HP on the wheels?
Above 6K rpm intake cams are stable at around -2 degrees and injectors pulse is NOT raising, so I think you are right about ignition timing. I never spotted this.
I must have missed that post about loosing power on non-RevUp above 6K, please provide pointer if not too much trouble. Thanks

Can someone please suggest me a good book on NA tuning? Thanks

Wired 24/7

iTrader: (2)

It sounds like upRev may be working on a tuning solution that lets you tune cam timing.

I guess that would be an ideal situation for people with the revup motor...

Anyway dovla I don't know for certain about openloop/closed loop but it seems pretty solid reasoning from everything I've seen. I believe it's due to emissions since most people will be cruising at under 4k.

I suppose I could try some not-quite-WOT runs and see if it does closed loop all the way to redline. That would be a good experiment...

Hydrazine

iTrader: (53)

Below stock?... Not possible unless something else is very wrong.

Wired 24/7

iTrader: (2)

maybe he meant rev-up going below stock up top. which is true.

nismology1

Not quite. It's showing cam angle advance relative to the crank angle. Essentially cam advance angle multiplied by two.

nismology1

Nope. Exactly the opposite. The closer it gets to zero the less overlap there is. The ECU retards the intake cam at high rpm to keep the intake valve open later in the stroke. This boosts high end power by taking advantage of the inertia of the intake charge.

nismology1

Why do you say that?

dovla

Interesting. Thanks

dovla

miamimax96, does INTK_CAM_TIM-B1 [or B2] (Deg CA) represents value of (c) in above pic?

Why multiplied by two?

In above SM chart, OEM (c) value is –6 and mine goes up to –2 degrees, would power increase if somehow I could change it to –6 degrees above 6K rpm? And similarly, if maximum advanced cam angle is 45 degrees (big if) should it be changed to 45 degrees below 3K rpm?

Thanks

Somewhere on the net I read following:

There are two easy ways to change the characteristics of your cam. Advancing and retarding the cam can move the power band up or down a few hundred rpm. Advance for more bottom end and retard for more top end. It usually takes about a 4-degree change for a driver to feel it. The second way is to change the valve lash.

nismology1

I don't know what the first part of your post means but value C in the chart is the crank angle at which the intake valve opens. -6 means the intake valve is opening at 6 crank degrees ATDC (after top dead center).
Because the cipher program expresses cam angle in crank degrees. Remember that the cams spin at exactly half the speed of the crank, so if the cipher says the cam angle advance is 20 degrees, this means the VTC sprocket is advancing the cam 10 degrees. Hope that makes sense.
When you say "goes up to -2" are you referring to the cam angle?
The -6 in the chart and your -2 are two seperate values.
The only way that question can be answered is on a load-based dyno where you can hold the RPM steady and tune the cam timing for peak torque.

Thanks

Wired 24/7

iTrader: (2)

Great info in my post, thanks guys! (Not being sarcastic)

dovla

miamimax96, thank you very much for answers. Finally some good info about cams, it seems to me that you know about cams. This is all Greek to me (no offense to Greeks). Please answer what you can, or how much your patience allows .

I always thought that Cipher parameters INTK_CAM_TIM-B1 (Deg CA) and INTK_CAM_TIM-B2 (Deg CA) represent cams angles at which they open intake valves. I had no clue that these Cipher degrees are actually half the TDC degrees values.

Yes, cam angle as reported by Cipher. I am lost again. First I though that in my Cipher logs above 6K rpm C is –2 degrees. Then, after reading your reply, I though that C is actually not –2 but -4 degrees in my chart. Both represent cams angle at which intake valves are open?




If the cams spin at exactly half the speed of the crank, why would VQ35DE cams angles separate like on this chart?



Are VQ35DE cams driven by VTC solenoids (oil pressure to the cams sprockets) and 0 degrees being solenoids are off?

Thanks again.

Nathan

I have just removed the front plate from VCT sprocket & can confirm miamimax's statement that the cypher cam log is expressed in deg of crankshaft position not camshft.
There is only about 20 deg max rotation inside the sprocket.

Wired 24/7

iTrader: (2)

Well... that's one way to do it!

myZter

iTrader: (7)

im reading all this and im just but its interesting..

Silo

iTrader: (1)

I was refering to this dyno:

http://motordyneengineering.com/imag.../Andy-Dyno.jpg

It is listed under MREV. Than there are some better ones under MREV-PLUS but the currently offered version is MREV-2 - I must admit, I have lost track! Enlighten me...

dovla

Thanks Nathan.


I am visual kind; here are the pics also for others