06black

what i've seen in the past was this.

as the "iruis" modulates its self to control oil pressure to the cam phasers Vs engine oil pressure. they have been known to "freak out" at >+3 deg over OE from time to time as viscosity changes.

this motor was going to be run on a "green" or energy friendly 0w oil at first, but as oil temp rises Vs worn oil that pressure has a vary non-linear, un-charitable pressure loss.

once it started happening, it would continue until it wanted to stop. sometimes it required replacing it.

HPT scans wont show it as it only looks for both CMD'd changes on the CAN and low-speed updates.

it might sound wild, but i've watched this happen on engine stands. you can physically see it go down with a poly-carb valve cover.

this is 2nd on my list of bad **** caused by tunes, only behind people whom don't ramp the cam down from peak advance on throttle lift. that's shattered more phase units, and taped more intake valves then i care to count.


also, watch the lead on this motor(Eco's in general) the pistons are not hot-spot friendly like a forged unit. when you start to get deposits, and you will over time, it'll glow the pistons in the low velocity areas and be a big tuning head ache(random hesitation, plug killing, ect.). and engine killer, the cyl temps are hot enough as-is.

Terminator2

You mean when someone adds -3 to the intake cam warm tables to only the high load areas and doesnt smooth the changes into the lover load areas. I noticed my car can run more timing with less KR on the 0W-30 Mobile1 I was running before.

06black

as you add positive advance (positive in the hpt table) you increase the amount of time and distance the cam has to travel, the car wants to make these changes in a fairly exact time, that's not tied to advance. so the more you increase advance, the faster it travels.

the same goes for its return, however with this faster speed you gain no more "force" to stop the cam, so it back travels more before being caught and re-centered.

do this enough / at the wrong time. you eat the valves.

only way to avoid this is to bump the table at a fairly linear rate as your peak increases. not many people do this. its sad.

as for the oil, well, your catching on more then most people.

Terminator2

That is the only way I cam tune. Small linear changes and I smooth those in so that as the loads decrease as you release the throttle sudden the phasers have to make that change very rapidly so if it is a drastic one appartently that is what is causing the crushed valves.

Iam Broke

iTrader: (10)

I noticed no flow improvements with the 'cam tune' from Term so I reverted back to stock cam tables. Valve damage scared me when I read about it a while back.

I don't follow why oil viscosity would let you run more advance though. Would a 10w30 be advantagous over 5w30 or not? Enlighten me.

P.S. Flogged it on the way home and saw only minor 1* tip in KR tonight. 0KR at WOT to redline in 2nd & 3rd a few times. Crawled around under the hood looking for any rubbing, found where they kissed the firewall putting in the engine. :facepalm: Heat wrapped lines were rubbing the firewall behind the turbo, so repositioned them a bit. Nothing major.

Doc

Always a great night when something is learned.

mkriebs

06 Black or Term... I'm not sure if i follow what you are saying about the cams. I run -3* compared to stock on my warm intake cam, and (not sure if this actually works) +3* on my warm exhaust cam tables. I run these from 2k rpm to redline, at 100% load and up. Is this fatal? I am kinda worried about it now...

If I am understanding you correctly, I should just smooth this out to the rest of the table, correct? I had it that way, but a comment from a fellow member (whom I have come to distrust their advice) brought me to change it back to the way I have it now.

Terminator2

It seems that because of the lower viscosity of 0W-30 over 5W-30 that the cam phasers can react faster to changes in cam angle that helps prevent KR. Also, the 0W-30 reduces internal friction a tad which helps as well.

Make sure you ramp those changes back down especially the high load and rpm areas to the lower load high rpm areas so that when you lift all of a sudden to shift the phasers dont have to make such a drastic change to the cam angle.

mkriebs

Cool, thanks! Would I just step it down 1* at a time? Or should I make it even more gradual than that?

Terminator2

I did mine at 0.5* increments I might even do 0.3* increments just to make sure.

Gimpster

I'm seeing flow improvment with cam timing experimentation. Not leaps and bounds but 1-1.5lb/min VE here and there. I've been mostly focused on the exhaust cam thus far. I have no dyno results to base what I'm doing in reality yet, but I do know whats worked for me on other vehicles. Never saw "massive" gains on the MR2 with cam tuning either, but every little bit counts. Think in the 5-10-15hp range.... also allows you to shift that powerband around too. My focus has been trying to improve top-end performance.

I do a lot of 60-100 and 70-100 comparisons and I feel like I'm making headway, but who knows.

I also happen to run 0W-30, but have been since before owning HPT so I have no basis of comparison for phase change. I'm a firm believer in M1 0W-30 (one of the best oils they have right now IMO) and run it in all of my vehicles.

Iam Broke

iTrader: (10)

Next change I'll go for the 0w-30 Mobil then, it'll be getting cold here by then anyway. I usually change it by 40% life left. I need all the KR help I can get.

My car smells like the past when I get on it now. Been a long time since I ran catless & leaded.

$5.56/gal is too steep a price to pay for the Renegade 110 but at least the experiment showed it CAN run 17* no KR on the right fuel. I'll work on the tune more after I get this tank ran out and keep looking for any vibration issues.

Where are the Knock sensor(s) located?

06black

mobil oil, in general, is total **** here in the states.

the USDM Green/Blue label stuff is utter junk. Grade3 base-stock at best.

the only oil I run in my cars any more is the now Total, used to be ELF stuff. they call it energy 9000 by total here.

5w-40 viscosity and its cheaper then Mobil 1. Not as good as RedLine (best stuff, period. almost 100% caster oil) but its not $12qt eaither.

the only good Mobil here in the state is the euro-car, black label 0w-40. its hot protection and film strength are kinda shitty. but much better then there normal 5w-30, ect.

Gimpster

While I general agree with you on US M1 products, I've done a lot of UOA's on M1 0w-30 and it seems to be a step above their other stuff. Need to do one on this car, but I don't see how they'd come back much different than my Volvo I traded in. You're not going to get super long drain intervals on this oil, but oh well thats not my bag anyway.

Honestly I'm not keeping this car forever, so if its no the purest of pure synth stocks......... oh well. We are talking about a Cobalt here and I'm in BFE Iowa. Besides going into Wal-Mart and getting 5Q of this for $22.00 and shopping/shipping oil around its my best option. I'm doing a lot better than most goons out there who'll pour in Kendall 10w-30 in the car dead of winter.

If you're really bored with life, come on over to bobistheoilguy and check out some of the results of M1 0w-30.

Iam Broke

iTrader: (10)

Today is the last day of my test. I'll be on fumes by the time I hit home to fill up with 93 again. No KR on the ~100 octane blend during many pulls this week. No CEL's. O2 response & fuel trims ok.

Inside of the pipe is grey instead of black when I get home. Renegade 110 octane.

I wouldn't do it often, but 2 gals in a half tank for the track is a possibility in the future.

cobaltltblue

I can't wait to get HPT..... I want to get into all this stuff....