#11
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Re: Using water-only system year-round? Feedback?
You don't blindly advance ignition timing because you risk unnecessary excessive cylinder combustion pressure past MBT...
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#12
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Re: Using water-only system year-round? Feedback?
Agreed. But What if you don't have access of a dyno or knock control system, how would you tune for w.i?
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#13
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Re: Using water-only system year-round? Feedback?
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First of all and despite my original post, I was only a noob with WI, not tuning or FI per-se. And that label is rapidly wearing off at this point anyway. Timing is not being advanced past MBT. That is an adjustable parameter as well - I just failed to mention it. When you advance, you adjust them both by the same amount. My settings are really: I can go up to 10 degrees of advance or retard: WOT MBT SPARK 1-3.8krpm +8* WOT MBT SPARK 4-4.8krpm +6* WOT MBT SPARK 5-7krpm +8* WOT SPARK 1-3.8krpm +8* WOT SPARK 4-4.8krpm +6* WOT SPARK 5-7krpm +8* The settings were not blindly changed at all. Not sure how you got that impression. The motor was well tuned before I started spraying with the HFS4 and we are talking about a stock motor with an aftermarket supercharger here. The MBT is determined by the PCM based on the given conditions. WOT MBT had to be lowered already to start with when the blower was installed by retarding the ignition timing (hard coded in the tune supplied by the Supercharger vendor). What I see myself as doing here is uninstalling the spark retard more so than just randomly cranking up the ignition timing by loosening a bolt and then twisting the distributor some arbitrary amount by hand to make power. I was actively logging the appropriate PIDs as well as monitoring them real time to see what the motor was doing. I could see if and when the PCM was pulling timing. WBO2 is monitored as well. I was most concerned with Long Term Spark Retard and backed off the spark advance in the appropriate RPM range when any hint of it is registered. The PCM adjusts in half degree increments. If we were in the danger zone, this reading would be going crazy - meaning that the PCM is going crazy by pulling the timing in response to the crazy knock. Advancing the WOT & WOT/MBT timing in 2 degree increments is also far from blind. That was the approach I took with the assumption that I would probably stop at 7-8 degrees of advance. I have read enough about WI/WMI to see that folks tend to get 6 to 10 degrees of ignition advance over not having it so used that as my ceiling - along with the device's limit of 10 degrees of advance or retard over the loaded tune. Bottom line is that I tuned the WOT spark advance with a target of 2-3 degrees of short term retard under extreme conditions and absolutely zero long term retard under all conditions. And like I mentioned, I eased into those settings. The other tack I took was to ease into the higher RPMs and boost levels as well. In fact, I now keep the tuner device on all of the time now with the following 4 soft gauges loaded (I'll try to post a pic later): ST SPK RETARD degrees LT SPK RETARD degrees AFR/WBO2 Percent (via analog input) WMI CCs (estimated - via analog input) I am also monitoring MAP and BARO on another gauge page - among other things. Until now, I was not considering an EGT sensor and controller but now that I am I am in this deep, it does seem like another great (off-dyno) tuning tool. With the tools that I have available, I feel that I do not really need a dyno to come close to ideal. That is not to say that an experienced tuner could not extract even more HP on a dyno because I believe that they can. it is just a question of how much more. Last edited by FI_Rubicon; 24-03-2016 at 06:51 PM. |
#14
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Re: Using water-only system year-round? Feedback?
I tuned my engine like FL_Rubicon mentioned here, the only difference is that I tune via ecu directly into the map not using knobs.
I set a fuel base map and an ignition base map with an amount of water/meth mixture and flow and make several WOT runs especially on 4th gear datalogging every run. After these runs I check all the plugs and see any signs of over advanced timing or detonation kinda old fashion style. If plugs look clean and engine felt torqy and responsive basemap is saved and used as it is. Regarding EGTs, I have one for every cylinder (4) and kinda seem like a waste of money since over advance show cooler egts while retard shows higher. Infact currently I just log the hottest cylinder only and study effects. Never had any help tuning the engine with them just knowing the values... Quote : "Advancing the WOT & WOT/MBT timing in 2 degree increments is also far from blind. That was the approach I took with the assumption that I would probably stop at 7-8 degrees of advance. I have read enough about WI/WMI to see that folks tend to get 6 to 10 degrees of ignition advance over not having it so used that as my ceiling - along with the device's limit of 10 degrees of advance or retard over the loaded tune." I was in that feeling for long time myself and I felt exactly how you feel like now. Until there was a day and decided to go my way and trial my own findings. The result, got about 10-15 Degrees of ignition timing on boost over the folks while running 14AFRs on low to mid-range boost (1-14psi) and 13.5AFRs on high boost (14-22psi) and injecting 44% W.I . The engine came so powerful that I needed to upgrade bigger and stickier tyres to WOT the car ! |
#15
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Re: Using water-only system year-round? Feedback?
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That would put excessive stress on the engine without any audible or knock sign. The PCM or ECU would not know you have past MBT because it would not knock given enough effective octane increase brought by the WI... The MBT is NOT determined by the PCM. It remains in open loop only to be modified by a few timing tables. For maximum engine performance and durability it is important not to exceed MBT and having the right timing tables set on the safe side of things. So yeah, sorry but I still consider yourself as a newbie based on your tuning strategy and explanations. |
#16
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Re: Using water-only system year-round? Feedback?
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This thread is completely off topic and I am on WM49 now anyway - not pure water. I found a local source for methanol that is not over priced so will start mixing my own (50/50 by weight). While there may be excess stress being put on the engine, it is really not clear what actual harm will be caused here without registering detonation. I feel that I am sized correctly and not overspraying. I have gain set to zero (12 o'clock). How many engines have you actually seen or heard of that failed as a result of not getting MBT correct where there was also no trace of detonation? How does one determine the correct MBT? Are you able to do this yourself or enlighten those of us who are interested? Do you have an ability to conduct a spark sweep process and can you possibly explain to the noobs how to do this without a dyno? That would be fantastic. I have definitely heard of an engine fail a swift death by detonation when the stock tune was left in place after a supercharger install. It was ugly. Catastrophic failure, requiring a complete engine replacement. In that case, the person posted about hearing a can of marbles when he hit the throttle (boost). The engine was toast in something like 50 miles. Fortunately he paid a shop to do the install and the shop goofed by forgetting to load the tune so the new motor was on them. Still - failure by messing up the MBT... Any actual cases? How does getting it wrong manifest itself short term? Lower HP? What about long term? Any documented cases? |
#17
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Re: Using water-only system year-round? Feedback?
To begin with could you post pictures of your plugs?
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#18
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Re: Using water-only system year-round? Feedback?
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A dyno is truly the best way to find optimum advance since the conditions will be perfect to measure. When you don't have access to a dyno you are required to tune on the same day, same stretch of road, same wind condition and start each run at an exact same speed. Some guys also use an accelerometer to complement tuning. That's how I started until I realised I could not get accurate enough. It was also very time consuming to reach a good tune. I know you spray a lot yourself so you could even have past MBT. If that is the case then expect the engine bearings and headgasket to be short lived just like FI_Rubicon... |
#19
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Re: Using water-only system year-round? Feedback?
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#20
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Re: Using water-only system year-round? Feedback?
More than likely the crank pulley bolt was improperly torqued to the right value or the bolt is the wrong type and or wrong steel used.
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