UTEC & Tuning Questions

[chuglobal]

The multiplier is the speed as which the ECU "learns." Then if you try the "Vishnu Reset," it would only affect the rate at which the ECU learns but not to actually fool the ECU into switching to its more aggressive map sooner? So the car would still run "rich?" So this whole theory is another "catch 22" because the car will not run any faster sooner?

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[Chi]

From the EcuTeK site:

The actual ignition timing used is the is a value from the base ignition map, plus a proportion of the ignition correction map (determined by the advance multiplier), plus a fine knock learning value from the above table.

So the advance multiplier is not the speed at which the ECU learns. It determines the amount of ignition correction advance that will be applied to the base ignition map. The higher the advance multiplier is, the more advance you will have. The reason for using the Vishnu Reset is because the ECU starts at a multiplier of "8" after a reset and takes it's time to reach a maximum of "16".. ie. if it ever gets there. The Vishnu Reset basically fools the ECU into jumping to it's maximum advance multiplier of "16".

There are 2 ignition correction maps besides the base ignition map. A high octane ignition map and a low octane ignition map. If you are running good gas along with the absence of knock, the ECU will happily advance your ignition using "a proportion of the ignition correction map (determined by the advance multiplier), plus a fine knock learning value". The fine knock learning value comes from a table which the ECU uses to store info regarding where knock as occurred in the past and uses this table to decrease your ignition timing where necessary.

Chuglobal, after doing the Vishnu Reset, your car should be in it's most aggressive mode.

I'm simplifying things a lot here. It's no wonder they patented this. I've never seen such an active ignition before...

Cheers!

[chuglobal]

1. So there a basically 3 main maps stored in the ECU: base, aggressive, and reserved. With a normal ECU reset, the ECU switches to the original base map w/ a multiplier of 8. The multiplier is used to take a "porportion" of the aggressive or reserved map and add it to the base map to give it an overall more aggressive calculation. The "Vishnu Reset" actually fools the ECU and tries to set the multiplier to 16 or as close as possible so the ECU will take a "larger" proportion of the aggressive map sooner. The ECU also inlcudes a table where past knock has occurred and applies less timing in those certain areas. Am I correct now?

2. Does the "aggressive" map include more timing and less fuel or just more timing?

3. How many cycles should I do of the 2500-4000rpm @ 2-5psi for 5-10 sec runs to finalize the "Vishnu Reset?"

[Chi]

1. You're almost correct on this. The "formula" is:
Base ignition map + proportion of the agressive map using the advance multiplier + reserved map. What you are refering to as the reserved map is actually the knock table.

2. The "aggressive" map = timing only. There are 2 separate maps for fuel; Lo Det Fuel Map and Hi Det Fuel Map. The engine runs on the Lo Det Fuel Map by default and when it detects excessive detonation, switches to the Hi Det Fuel Map.

3. One should be enough.

Some notes:
Base = Main Ignition Map
Aggressive = Ignition Correction Map
Reserved = Learned Ignition Correction Map

[chuglobal]

Thanks ... I theory was "close." Also after holding the revs at the certain rpm for the "Vishnu Reset," do I go WOT till redline or do I let it go back to idle then turn off the car then restart the car and drive normally. Does any of it matter?

[Si2WRX]

I suspect it starts on the hi-det map by default. The WRX clearly runs pig rich after a reset. As it's run, it switches maps to the low-det (slightly leaner) map.

[Chi]

No, it starts off with the low-det map.

IMHO, the stock low-det map is pig rich already. When it switches to the hi-det map, it basically drowns the engine.

chuglobal, after the Vishnu Reset, just drive normally.

[chuglobal]

1. Is there a way to make the ECU run leaner "quicker?" I know the majority of my knocks were due to too much fuel because I ran a test and the only variable was the way extra fuel which caused knock. Is the "Vishnu Reset" is only good for timing then how does fuel correlate?

2. My "normal" driving is redlining when I have a chance, it's too much fun. Should I just drive "normally" then w/out having shut off the car? I'm going to be doing to "Vishnu Reset" tonight. I have the day off work tomorrow.

[Chi]

1. There is no way to make the ECU run leaner "quicker". If you are knocking because of excess fuel, I suggest that you take your car to a tuner and have it tuned. A EcuTeK reflash goes great with a UTEC!

2. Yes, just drive normally after performing the Vishnu Reset. Don't hit the rev limiter...

Cheers!

[chuglobal]

1. I also heard the EcuTek works well w/ the UTEC. I have a theory base on my "normal" driving expereinces; everytime I reset the ECU, thus richer mixture, I get "more" knock till after 150miles which is when the ECU leans out the A/F. Also if I do the EcuTek reflash, will I not need to retune the UTEC again?

2. Too late, I already did some quick runs tonight. I have 2 sets of nice hills near my place. I did 5+ runs at 2500-3000 rpm @ 3-5psi for 5+ secs each in 4th gear. It's so nice to do some road tuning and know I'm not breaking any laws. I'm driving home a few minutes later and took 1st gear to redline twice ... humm I wonder if it'll change the "Vishnu Reset" process any.

[chuglobal]

1. I really hate getting bad gas. I figured a gas station would have a new batch of gas more than once a week; I've now gotten 2 tanks of bad gas from BP on Johnson Ferry near Lower Roswell w/in the last week. Now I have to burn through this tank then go to QT where "so far" I've been successful w/ them.

2. I just added the NOS Octane Booster from Autozone. It really killed me last night when I went "street racing" and I've never seen that many knocks since I had the UTEC, I got knock in every 2nd, 3rd, and 4th. Does anyone know how long the octane "booster" takes before it dilutes into the gas? I read some of the other bottles and hey say usually near an empty tank but isn't that ironic since if I had an empty tank then I just get more fuel and hopefully solve the bad gas problem? I ran the car hard after adding it and it still knocks like crazy when WOT?

[Chi]

Man, you must have a real problem with gas in your area...

Don't know what to say... except try some gas stations farther away?

[chuglobal]

1. It was definitely a bad tank of gas from BP Oil. I'm very disappointed that it caused me this magnitude of problems. The knocks are definitely decreasing now. I had to drive around for like 5+ hrs to burn off the gas yesterday ... I never circled 285 till yesterday.

2. The knocks now are because of overboosting situations ... what's weird because the ECU seems "more" sensitive to the UTEC control of the FBC. I did "NOT" touch the boost settings and now I'm suddenly getting 18psi+ which I use to only get 16.5psi? I have a feeling by resetting the ECU many times recently caused it to learn "something" which I can't figure out. I got a bunch of knocks this morning but the majority was due to the overboosting situation.

3. Also I was looking over the knock log and noticed that the Injector Duty hit 100% at some points. I don't remember it being so high, I remembered low 90s% sometimes but 99-100% was weird? Why is this happening?

[mbiker97]

When you reset your ECU the fuel trims went to 0. After driving a couple days the ECU will learn new fuel trims (hopefully less fuel) and you should be fine.

[chuglobal]

1. Honestly, I never looked at a log after a fresh ECU reset. I just happened to notice the Injector Dute Cycle at some really high number at or near 100% when glancing at the knock log.

2. Why would the the FBC start acting weird and causing overboosting? "Nothing" was touched in the UTEC boost variable, it just started to climb to 18psi+ ... yes it was real cold this morning ... low 40s ... but that was a little extreme. I saw my analog boost gauge go past 18+psi when it usually use to only go to 16psi?

[PaulRex]

Originally posted by chuglobal
1. Honestly, I never looked at a log after a fresh ECU reset. I just happened to notice the Injector Dute Cycle at some really high number at or near 100% when glancing at the knock log.

2. Why would the the FBC start acting weird and causing overboosting? "Nothing" was touched in the UTEC boost variable, it just started to climb to 18psi+ ... yes it was real cold this morning ... low 40s ... but that was a little extreme. I saw my analog boost gauge go past 18+psi when it usually use to only go to 16psi?

Perhaps just the weather, I had to lower my open loop boost settings in my map by over 15 across the board above 4,500rpms this past week it has gotten so cold here. Now i just made two identical maps one with cold weather boost setting and one with normal weather boost settings

[chuglobal]

So if you were running say "85" in the boost above 4500 rpm, now you're running "70" in those ranges? it should be in the 60s by the time I get off work so I do some WOT and see what the boost changes to, I assume the low 40s were that optimal for the UTEC and how it was orignally tunned for mid 50s.

[PaulRex]

Originally posted by chuglobal
So if you were running say "85" in the boost above 4500 rpm, now you're running "70" in those ranges? it should be in the 60s by the time I get off work so I do some WOT and see what the boost changes to, I assume the low 40s were that optimal for the UTEC and how it was orignally tunned for mid 50s.

Exactly, I also have my ABC closed and just use the boost map for boost tuning so maybe my values higher than most peoples. Once i saw the boost getting up to 18-19psi in 4th and 5th gears i just made another map with the lower boost values..

[chuglobal]

1. I took me 1/2 of the new tank to almost completely get rid of the "bad" gas from BP Oil. I don't know the exact timing however I started to get 0 knocks, which is normal, around 1/2 a tank of gas. I still can't believe what happened.

2. I think the bad gas + extreme change into cold weather caused my knocks. I was hitting 18psi+ which is NOT a good thing. I turned the ABC 1/4 turn in and things seem to be at 16.5-17psi in the low 50s which is fine w/ me.

3. I also noticed today the Injector Duty Cycles are going back to 80s-90s once again, I hit 100 miles today since my ECU reset two night ago so I'm assuming the ECU is changing the maps to be less rich.

4. I also really think that my previous knocks on the base Stage 2 map was caused mainly due to the rich A/F variables. I did pull timing which now going back and thinking, I should have tunned for correct A/F then change timing either up or down ... up is what is preferred.

[mbiker97]

4. Generally the tuning order is boost -> fuel -> timing. So now your getting a hang of things. I'm glad your IDC's went down. That could have definately been causing some knock.

[chuglobal]

1. Why didn't some mention to me earlier that the order for tuning was boost > A/F > timing? I was gathering my conclusion on what I have read and seen.

2. I wish I had a dyno or something to truely measure everything w/out the worry of cops doing 128mph runs in 4th. I really want to test my knock theory on the base Stage 2 map is caused more by rich A/F then too advanced timing.

[dosage0]

Originally posted by chuglobal
I just added the NOS Octane Booster from Autozone. It really killed me last night when I went "street racing" and I've never seen that many knocks since I had the UTEC, I got knock in every 2nd, 3rd, and 4th. Does anyone know how long the octane "booster" takes before it dilutes into the gas? I read some of the other bottles and hey say usually near an empty tank but isn't that ironic since if I had an empty tank then I just get more fuel and hopefully solve the bad gas problem? I ran the car hard after adding it and it still knocks like crazy when WOT?

1) That NOS Octane Booster from Autozone adds POINT 7. Which is pretty crappy for the 10.99 that it costs. That basically changes your 91 octane (or whatever) to 91.7. Even that is probably stretching it because it is a generic figure that is supposed to cover every size of gas tank. Next time, add a gallon of Toulene. You can find it at Sherman Williams. Ask for the contractor discount and they sell it to you 5 gallons for 27.00. Toulene is 114 octane and will up your tank ~ 1.5 for each gallon in a Subaru. Basically you can dump in two gallons of toulene for a bottle of that NOS stuff. That would make 91 octane gas ~ 94 (93.9).

Hope that helps,

Rob

[chuglobal]

1. I never had a serious problem w/ a "bad" tank of gas until this past weekend. I was in a panic and thus the reason why I did not know the OTC Octane Booster suck. If I knew I would have tried another avenue.

2. What exactly is "Toulene?" Is it "race" gas being it's 114 Octane or just some chemical additive? Is it bad for the engine to add Toulene? My next question is why Sherman Williams carries "race" gas? Since the Subaru carries a 15.9 gallons capacity, 114 Octane would change the Octane on average 1.5+ increase for each gallon of 114 added?

[Si2WRX]

Toluene is pure 114 oct and is a main ingredient in gasoline. It is also a paint thinner So yes, Sherwin Williams carries it and you can run it in your gas tank.

If you put in one gallon of Toluene in with a tank full of gas, you'll get an octane rating of somewhere around 95.

[chuglobal]

So why wouldn't people just fill up w/ 93 Octane at 11 gallons for $15 then go get 4 gallons on Toulene and run on average 101 Octane for <$35 instead of just buying "race" gas would is like $70+?