I was about to explain almost the same after getting back home.
That's also what is explained on te Reg Riener site linked some posts before..
That's also what is explained on te Reg Riener site linked some posts before..
Planning 2014 Standalone Upgrade - Question...
- Thread starter Grandavi
- Start date
IndigoMKII;1914671 said:
This is easier to understand than what Reg wrote (for me anyway). From what I now understand, the TCCS functions properly all the way up to about 3500 RPM. At that point, it sees max air incoming so dumps max fuel to keep it from leaning out. With my AFPR setup currently, this is allowing my AFR's to run to 10:1 (could be different, but seems to be the limit of my Wideband reading). If I back off the fuel pressure using my AFPR a couple pounds, this would reduce the pressure going to the 550's so that at WOT I wouldn't be dumping as much fuel when the 550's open fully. (or.. shouldn't be) Playing with the screw is just trying to adjust it from going as heavy until later RPM's.
Do I have that right?
I wont have to worry about running lean and detonating because the TCCS will always run full injectors when it gets to the WOT position. My only worry would be that I dont reduce the pressure so much I cant idle and that my AFR's are approx. 14.7 when running normally.
You do know that running too rich can damage the motor right?
"OK, I’m just going to turn the fuel pressure way up and run extra fat, that way I won’t hurt anything. If you run too rich, you will “wash out” the rings. First, excess fuel will run down the cylinders taking the lubricating oil with it. This promotes direct metal-to-metal contact between the rings and the cylinder wall. This contact does several things. The upper ring begins to wear quickly. The middle ring is actually designed as a tapered oil scraper (it is not used for compression control at all) and the taper will begin to wear down to where it becomes flat rather than angled. When that happens, it can no longer control oil away from the combustion chamber. The last thing that happens is that pretty cross hatch design begins to wear off of the cylinder wall. While most people think that the cross hatch is there to help seat the rings, it also has a secondary purpose. That is to hold microscopic amounts of oil in the grooves to help lubricate ring to cylinder walls. With the walls smooth and no oil control help from the middle ring and a tired upper ring, oil will begin to mix with fuel in the combustion chamber. When this happens, your 93 octane fuel probably hits a value of about 80. Then detonation comes into play and begins to beat holes in the pistons, among other things. "
http://www.laskeyracing.com/shop/breakin.htm
"OK, I’m just going to turn the fuel pressure way up and run extra fat, that way I won’t hurt anything. If you run too rich, you will “wash out” the rings. First, excess fuel will run down the cylinders taking the lubricating oil with it. This promotes direct metal-to-metal contact between the rings and the cylinder wall. This contact does several things. The upper ring begins to wear quickly. The middle ring is actually designed as a tapered oil scraper (it is not used for compression control at all) and the taper will begin to wear down to where it becomes flat rather than angled. When that happens, it can no longer control oil away from the combustion chamber. The last thing that happens is that pretty cross hatch design begins to wear off of the cylinder wall. While most people think that the cross hatch is there to help seat the rings, it also has a secondary purpose. That is to hold microscopic amounts of oil in the grooves to help lubricate ring to cylinder walls. With the walls smooth and no oil control help from the middle ring and a tired upper ring, oil will begin to mix with fuel in the combustion chamber. When this happens, your 93 octane fuel probably hits a value of about 80. Then detonation comes into play and begins to beat holes in the pistons, among other things. "
http://www.laskeyracing.com/shop/breakin.htm
Sees max air at 3500 rpm, huh? The ECU tables are based on load, more accurately volumetric efficiency, which is (measured mass flow per crankshaft rotation / theoretical mass flow). The tables go up to redline and ~100% load, there is nothing special about 3500 rpm.
AFPR is set to stock fuel pressure. The only time I get to 10:1 is at WOT conditions from what I can tell. Didn't think running stock fuel pressure with 550's would damage the engine. (91 Octane here btw)
As I said earlier, I am new to a lot of this, but from everything I have read and the people I have talked with, how I am currently running is perfectly fine. My AFR's are roughly 14.7:1 normally. When I go into boost and WOT is when it drops to 10:1 at about 3500 RPM.
If I said something wrong, its due to my learning, not simply being stupid. I am just getting a grip on playing with the AFPR and AFM prior to adjusting anything. The shop that put the car together tells me I'm fine running as is without any worries. (It's the shop that developed the AFM/550 mod specifications.. so I tend to believe them). I realise that a saturated combustion chamber will have issues especially if the gas goes into the crankcase (thinning the oil). The car never smells rich. It idles correctly, runs correctly. It just goes very rich at full throttle/boost for the couple seconds that I run like that. Doubt it will be enough to do anything harmful to my cylinders.
Going back to tuning with the AFM and AFPR, the only way I see anything being changed (after thinking on it a bit) is at idle. Wont the TCCS relearn whatever change I make and adjust to its internal tables? The whole AFM adjustment seems a little "stop-gap" measure which is why I was asking about the standalone systems. By reducing the fuel pressure, all I am in effect doing is trying to lean out the top end capabilities. In the end.. I keep seeing more and more reasons to be going to standalone.
just as a further note to SC61... this is a brand new engine.. the walls will not be smooth, nor will any of my rings be "tired". Good link regarding the break-in period.. although its talking about a whole different build than mine.
As I said earlier, I am new to a lot of this, but from everything I have read and the people I have talked with, how I am currently running is perfectly fine. My AFR's are roughly 14.7:1 normally. When I go into boost and WOT is when it drops to 10:1 at about 3500 RPM.
If I said something wrong, its due to my learning, not simply being stupid. I am just getting a grip on playing with the AFPR and AFM prior to adjusting anything. The shop that put the car together tells me I'm fine running as is without any worries. (It's the shop that developed the AFM/550 mod specifications.. so I tend to believe them). I realise that a saturated combustion chamber will have issues especially if the gas goes into the crankcase (thinning the oil). The car never smells rich. It idles correctly, runs correctly. It just goes very rich at full throttle/boost for the couple seconds that I run like that. Doubt it will be enough to do anything harmful to my cylinders.
Going back to tuning with the AFM and AFPR, the only way I see anything being changed (after thinking on it a bit) is at idle. Wont the TCCS relearn whatever change I make and adjust to its internal tables? The whole AFM adjustment seems a little "stop-gap" measure which is why I was asking about the standalone systems. By reducing the fuel pressure, all I am in effect doing is trying to lean out the top end capabilities. In the end.. I keep seeing more and more reasons to be going to standalone.
just as a further note to SC61... this is a brand new engine.. the walls will not be smooth, nor will any of my rings be "tired". Good link regarding the break-in period.. although its talking about a whole different build than mine.
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I worded that wrong... but if your here to slap me upside the head for wording... your just wearing out your keyboard. my AFR's are at 10.0:1 at approximately 3500. "Pig-rich". Satisfied?3p141592654;1914790 said:
(All in reference to the dyno sheet)
Yes, in the tuning area (not really tuning with only an AFM), I am quite stupid.
3p141592654;1914790 said:
When does the ecu click over to open loop then?
My car will run 14.7 afr til mid 3000 rpms then will go over to 11.0, all while WOT.
SC61 MK3;1914788 said:
So, how would oil introduce itself into the combustion chamber if the cylinder walls are being washed of all the oil? Also, there's fresh fuel introduced to the cylinder on each intake stroke. How would this affect the octane rating?
Grandavi;1914814 said:
I'm here to correct bad information, and what you wrote is wrong. I'm sorry if I hurt your feelings in the process. I've spent many hours figuring out the ecu code, so I know how it works.
As for the questions about when does the ECU go open loop, I will repost here what I have posted elsewhere on the subject.
3p141592654;1914827 said:
Was just responding to what I took as a typical "omg this guy is stupid" remark, no hurt feelings, they just bug me a bit.
Going to see if I have this figured out correctly....
the 2800 rpm - 48% and 7600 rpm - 0% are basic table values for normal operation, meaning that if I am doing a normal constant acceleration (as in normal daily driving), the map values will respond in a linear curve (more or less).
This generally just reflects engine RPM and what I could consider a "base" model.
When I go WOT, the throttle position sensor will send information to the TCCS causing it to go open loop regardless what the engine is doing (not immediately, but much faster than normal) regarless of RPM. This is why I get 10:1 AFR at WOT when I hit 3500 RPM.
If I want to avoid this, I cant really go over the 48% that you quoted for throttle position.
If all the above is correct thinking, then staying stock fuel pressure with the Lexus AFM setup currently is about as good as it gets. I could lean out the fuel feed by lowering the fuel pressure, I think, although I am a little adverse to doing that because "lean" scares me a little more than "rich". Plus, I don't know if the benefits are worth it.
My only 2 options is to introduce a piggyback fuel management system or to go full standalone. However, I am starting to wonder if the costs involved in going full standalone are worth it relative to the return for my power goals. (I just want a fast street car, not an awesome quarter mile runner). Plus, the stand alone seems to be the "pinnacle" for what I eventually want because once tuned correctly, my car will have its optimum power, fuel economy and longevity as it will be truly reading what goes on in the engine, rather than dealing with "safe" values that have to be bypassed for performance.
Do I have this all correct?
(running rich like I am shouldn't hurt the engine generally speaking)
Sorry to go off topic here then, if I go WOT at say 1800 rpm in 3rd gear, why does my afr stay near stoich til mid 3000 rpms? I thought open loop happened regardless of RPM as well but my afr's are saying it doesn't switch over til mid 3000 rpms, or atleast that's when they go over to 11.0
In order to dial in the engine management with the sophistication of the factory ECU, you would need to spend hundreds of dyno hours in a climate controlled room to cover the operating conditions a car sees in daily operation. The stock ECU (25+ years old now) has over a hundred maps and tables to fixup operating conditions for all sorts of conditions and modes, and to extract the maximum mileage and power while maintaining the drivability people expect, keep the catalyst conditioned for good emissions, and respond to a wide range of fuel quality. You will not get that level of sophistication from a standalone. A very common approach with standalones is to throw fuel at a drivability issue, which results in poor overall fuel economy. This is then sold to the customer as the price of performance when its actually the price of a one-size fits all solution.
Anyway, my intent it not to dissuade you from going that route, just that there is no free lunch, and to go in with your eyes open. Weigh the pros and cons carefully.
Anyway, my intent it not to dissuade you from going that route, just that there is no free lunch, and to go in with your eyes open. Weigh the pros and cons carefully.
IndigoMKII;1914858 said:
Because the ECU will not switch instantly to/from open-loop when conditions are met, there is a count down timer for the switch, and its on the order of a few seconds if I remember correctly. Also, it requires more load to switch over at low rpms. You would have to datalog to capture what is going on, but the decision logic is as I stated. There is also hysteresis built in to prevent rapid switching back and forth when you are on the borderline. Another consideration is that there is an open loop fuel enrichment map. I may have published it in my ECU thread. Anyway, the amount of enrichment is minimal near the switchover, and then fuel is added as you move over to the high load/high rpm region, so going open loop does not imply an immediate rich mixture, it will however start to move away from stoich since it is no longer cross counting the O2 sensor.
Here is the fuel enrichment map for the 7M A/T 90-92 ECU. Other are similar.
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Oh well that makes sense now, so the car is on a few second timer for the open loop at a preset load% and by the time the car clicks over to full open map and high load/rpm the rpms are already near mid 3k rpms. Makes sense.
3p141592654;1914859 said:
Okay, thats a totally new look at standalone systems. I do know that with my standalone system I was planning, Reg Reimer was planning to spend about a week tuning it. The tuning alone cost as much (if not more) than the actual standalone and installation. I watched as he tuned a BMW and was a little overwhelmed at how he could understand the amount of values that he was paging through.
I had thought that a standalone system would have exceeded the stock ECU because it was monitoring things closer and finer and could adjust for more variables. Now I think that I may have that backwards. This makes me rethink things a bit.
So, overall, if a person isn't trying to push the thresholds of a 7MGTE and just looking for a nice 300-350 rwhp runner, is it wiser to stay with the Lexus AFM "lies" and let the stock ECU do its job? The performance of my car is excellent currently as it sit in comparison to what it was before I started, and I probably would have been happy with a 3" exhaust by itself. Just that little change is such a huge difference in feel for the car.
Running 18x10's on the back (no real hook on those tires with such a small sidewall) I break traction in second when boost kicks in as the car sits.
Perhaps I am better off just running as is and let the car do its thing. I do know before I used to get about 25+ mpg on the highway with cruise sitting at 120 kph (about 70 mph I think). The performance used to be nice, but not impressive. Currently I consider it impressive. (for just a normal street car). Im not really happy with the 10:1 at WOT, but from everything I am reading so far, and seeing when that occurs (which is quite rare really) my setup should be safe to run as is. Throwing 3-4000 dollars at a tuner isn't my favorite way to spend money, although I was prepared to do so if it would keep the car running longer.
If you did a little bit of fine tuning yourself with the afpr and the lex afm screw, you can get it a little bit closer to 11.0 at WOT. Mine goes to 11.0 at WOT then slowly creeps back to 10.5 where it settles, but by then I'm shifting.
Gotta wait for a new turbo now, the new one is peeing oil... 600 km on it and the seals are letting loose... At least I fairly certain that's what's happening...
It's getting worse, so the car ain't gonna run until I pull the turbo.
It's getting worse, so the car ain't gonna run until I pull the turbo.
Exactly that, however it is also now smoking on idle. Aaron at Driftmotion told me just to send it back and he'll take care of it.
With a piggyback ecu I would think you could trim the factory settings and still utilize all of its maps.
I'm not sure if that would yield a more accurate and wide ranged output, but I would think so. I'm sure pi could add some insight.
The standalone just isn't going to provide much of a gain unless you have goals well above the Yota ecu.
Sent from my Galaxy Nexus using Tapatalk 2
I'm not sure if that would yield a more accurate and wide ranged output, but I would think so. I'm sure pi could add some insight.
The standalone just isn't going to provide much of a gain unless you have goals well above the Yota ecu.
Sent from my Galaxy Nexus using Tapatalk 2