The EZK computer- safeguarding or self tuning?
10-19-2015, 11:11 AM
#16
Rennlist Member
Thread Starter
Fred,
Are you running the same plugs (heat-wise) across all cylinders? WR7DC is stock, in your climate you probably want WR6DC. Then try WR5DC in the hotter cylinders.
There's nothing wrong with letting the EZK do its job and take out a few degrees on a few cylinders. When it starts retarding all (or nearly all) of the cylinders, then you are not accomplishing anything. And if it is pulling out more than 3-4 deg then you are eating into margin that you might otherwise need.
A couple of interesting data points: Fuel does vary of course, and altitude and temperature are big variables. Heading to Wichita, we filled in Denver and then headed downhill across Colorado and into Nebraska, car running fine in the increasing heat (an decreasing altitude). At one point, when Sharktuner happened to be logging, I nailed it to get around some pesky traffic ... Bwahhhh, lovely sound, but some smoke out the back and when I looked at ST's log it showed shows 9 deg retard on all 8 cylinders. Yikes! Higher-altitude fuel mix (lower octane) and high temps used up 9 deg and then some.
Our GT has been tuned as you suggest for at least the last 100K miles. Louie's theory was to let the EZK do its job and I have followed that also, setting the top-end advance so that the EZK would pull out a few degrees up to 5 deg) from 2-3 cylinders. But as our Kansas trip pointed out, we need margin for varied terrain, temperature and fuel. So I always had this nagging worry about what we were doing to rod bearings.
Another data point: Doing some tuning on a local dyno shop, I am watching Sharktuner and the tech is watching the dyno screen and rearview mirror. "Try taking out a couple of degrees above 5000" he says, sure enough Sharkplotter shows some retard there-- but just the usual 3-4 deg. He is seeing smoke-rings in the mirror, a sign of detonation. I take out 3 deg, we run again, more power-- 4 or 5 more hp, not less. "Try a couple more" he says, another few hp. Interesting, very interesting.
So what about the rod bearings? At 250K miles we disassemble the motor to see what's in there, and the rod bearings are perfect. Never been changed as far as we know, all marked identically with a Porsche logo, can't tell 2/6 from any others and no signs of detonation on bearings or pistons.
So I've got no evidence that letting the EZK do its job on a few cylinders does any harm, but it is also clear that you want a pretty fat margin for the unexpected. And adding timing doesn't necessarily lead to more horsepower. And neither can logging, but it certainly can tell interesting stories.
Cheers,
Are you running the same plugs (heat-wise) across all cylinders? WR7DC is stock, in your climate you probably want WR6DC. Then try WR5DC in the hotter cylinders.
There's nothing wrong with letting the EZK do its job and take out a few degrees on a few cylinders. When it starts retarding all (or nearly all) of the cylinders, then you are not accomplishing anything. And if it is pulling out more than 3-4 deg then you are eating into margin that you might otherwise need.
A couple of interesting data points: Fuel does vary of course, and altitude and temperature are big variables. Heading to Wichita, we filled in Denver and then headed downhill across Colorado and into Nebraska, car running fine in the increasing heat (an decreasing altitude). At one point, when Sharktuner happened to be logging, I nailed it to get around some pesky traffic ... Bwahhhh, lovely sound, but some smoke out the back and when I looked at ST's log it showed shows 9 deg retard on all 8 cylinders. Yikes! Higher-altitude fuel mix (lower octane) and high temps used up 9 deg and then some.
Our GT has been tuned as you suggest for at least the last 100K miles. Louie's theory was to let the EZK do its job and I have followed that also, setting the top-end advance so that the EZK would pull out a few degrees up to 5 deg) from 2-3 cylinders. But as our Kansas trip pointed out, we need margin for varied terrain, temperature and fuel. So I always had this nagging worry about what we were doing to rod bearings.
Another data point: Doing some tuning on a local dyno shop, I am watching Sharktuner and the tech is watching the dyno screen and rearview mirror. "Try taking out a couple of degrees above 5000" he says, sure enough Sharkplotter shows some retard there-- but just the usual 3-4 deg. He is seeing smoke-rings in the mirror, a sign of detonation. I take out 3 deg, we run again, more power-- 4 or 5 more hp, not less. "Try a couple more" he says, another few hp. Interesting, very interesting.
So what about the rod bearings? At 250K miles we disassemble the motor to see what's in there, and the rod bearings are perfect. Never been changed as far as we know, all marked identically with a Porsche logo, can't tell 2/6 from any others and no signs of detonation on bearings or pistons.
So I've got no evidence that letting the EZK do its job on a few cylinders does any harm, but it is also clear that you want a pretty fat margin for the unexpected. And adding timing doesn't necessarily lead to more horsepower. And neither can logging, but it certainly can tell interesting stories.
Cheers,
As always an interesting post that tends to confirm one of my assumptions and that is in some circumstances you can run with too much advance and lose power and that is my dilemma as I do not have access to a dyno.
The problem you explained is in part explained by the fact that at altitude the gasoline is at a lower pressure so low mol weight compounds flash off that much easier so cannot be in the blend to the same extent as they can at sea level. Cannot think why you had a problem with such retard needed as you descended to lower elevations but interesting nonetheless given the reduction in boiling point- I will have to have a think about that one.
On the plug front I currently have WR6's in the central cylinders after a suggestion from Greg, I also have some WR5's to try but at the moment I am off the road pending some maintenance items- when I get going again I intend to try the Wr5's in the central cylinders and the WR6'son the outer four.
One of things I mentioned earlier was that when studying the maps in ST2 I noticed that for cat models the stock maps run more advance. This puzzled me initially until [Ken] advised that because the exhaust is more restrictive with cats it needs more advance to compensate. that logic holding, it thus stands to reason that when running a faster exhaust system with Louie's x-pipe [no front silencer] and a big muffler with a RMB's my timing should logically require less advance than stock non cat maps and this is what ST2 told. Initially I thought it might be a warning that something was wrong but with hindsight probably not.
Just a pity I do not have the luxury of a hands on opinion from folks like yourself but it has been an interesting journey and my motor runs as well as it ever has.
At least our gasoline is pretty consistent in quality as it comes out of one refinery and that runs the same crude mix [Oman Export blend] 24/7.
My current mapping was determined during the hot months [I usually do this] but it might be interesting to try a "winter tune" for the cooler months.
Rgds
Fred
10-19-2015, 12:26 PM
#17
Nordschleife Master
On exhaust changes and ignition timing: It would be very useful to understand by which channel the exhaust changes impact the required ignition timing. The first possibility is that the exhaust change increases the vol-F and therefore the denser charge will require less timing for maximum torque. The second possibility is that the exhaust change hiders the combustion chamber evacuation of exhaust gasses and reduces the knock limited ignition advance. In both cases, you should run less timing but almost everything else that is relevant about the change is diametrically opposite.
If one is really interested in understanding which mechanism is at play, one way to do that is to do test runs before and after with high-octane race gas which largely takes the knock out of play for these tuning levels. Does it still want less timing on race gas? If so, it's a good change. If it actually wants more timing on race gas after the exhaust change, then it's probably a bad change.
If one is really interested in understanding which mechanism is at play, one way to do that is to do test runs before and after with high-octane race gas which largely takes the knock out of play for these tuning levels. Does it still want less timing on race gas? If so, it's a good change. If it actually wants more timing on race gas after the exhaust change, then it's probably a bad change.
10-20-2015, 03:35 AM
#18
Three Wheelin'
A couple of interesting data points: Fuel does vary of course, and altitude and temperature are big variables. Heading to Wichita, we filled in Denver and then headed downhill across Colorado and into Nebraska, car running fine in the increasing heat (an decreasing altitude). At one point, when Sharktuner happened to be logging, I nailed it to get around some pesky traffic ... Bwahhhh, lovely sound, but some smoke out the back and when I looked at ST's log it showed shows 9 deg retard on all 8 cylinders. Yikes! Higher-altitude fuel mix (lower octane) and high temps used up 9 deg and then some.
Cheers,
Cheers,
You may want to carry some Toluol, or Xylene with you for those situations where you cannot get the gasoline you have your car tuned to require. Usually, either product or both can be found a Home Depot. They are 106 to 107 octane so mix 5% to 10% with what fuel you have in the tank. You can determine the end octane by using simple ratio of octane and volume of current fuel with the volume of Toluene at 106 octane added. The engine will be harder to start with either of these added and I wouldn't recommend adding more than 10%. Both of these octane enhancing agents are routinely added to fuel to boost the octane by the fuel manufacturers so you aren't doing anything rash.
10-20-2015, 08:25 AM
#19
Rennlist Member
Thread Starter
Jim,
You may want to carry some Toluol, or Xylene with you for those situations where you cannot get the gasoline you have your car tuned to require. Usually, either product or both can be found a Home Depot. They are 106 to 107 octane so mix 5% to 10% with what fuel you have in the tank. You can determine the end octane by using simple ratio of octane and volume of current fuel with the volume of Toluene at 106 octane added. The engine will be harder to start with either of these added and I wouldn't recommend adding more than 10%. Both of these octane enhancing agents are routinely added to fuel to boost the octane by the fuel manufacturers so you aren't doing anything rash.
You may want to carry some Toluol, or Xylene with you for those situations where you cannot get the gasoline you have your car tuned to require. Usually, either product or both can be found a Home Depot. They are 106 to 107 octane so mix 5% to 10% with what fuel you have in the tank. You can determine the end octane by using simple ratio of octane and volume of current fuel with the volume of Toluene at 106 octane added. The engine will be harder to start with either of these added and I wouldn't recommend adding more than 10%. Both of these octane enhancing agents are routinely added to fuel to boost the octane by the fuel manufacturers so you aren't doing anything rash.
I did not know you were an alchemist as well- [Toluol is an old name for Toluene]!
Toluene was actually used as race fuel by the F1 teams in the "Turbo era" in the early 80's- I seem to remember that they had to cut it back a bit to meet the F1 octane limit. The problem with it is it needs heat to atomise [hence the difficult starting issue] and they routed the fuel flow via a heat exchanger in the exhaust to heat it up so it would atomise.
I have wondered if I can get a supply locally as heat is the least of my problems over here. I have a feeling it may be used in paint stripper or something similar. Given we probably have too much LPG in our fuel, throwing in some toluene might in fact be a good thing. 10% in the mix would take our 95 RON to something just over 96.
The best fuel you can ever get [if you could get it] would be platformate straight out of the refinery platformer unit but you would need to own a refinery to get hold of it!
Rgds
Fred
10-20-2015, 05:37 PM
#20
Three Wheelin'
Hi Louie,
I did not know you were an alchemist as well- [Toluol is an old name for Toluene]!
Toluene was actually used as race fuel by the F1 teams in the "Turbo era" in the early 80's- I seem to remember that they had to cut it back a bit to meet the F1 octane limit. The problem with it is it needs heat to atomise [hence the difficult starting issue] and they routed the fuel flow via a heat exchanger in the exhaust to heat it up so it would atomise.
I have wondered if I can get a supply locally as heat is the least of my problems over here. I have a feeling it may be used in paint stripper or something similar. Given we probably have too much LPG in our fuel, throwing in some toluene might in fact be a good thing. 10% in the mix would take our 95 RON to something just over 96.
The best fuel you can ever get [if you could get it] would be platformate straight out of the refinery platformer unit but you would need to own a refinery to get hold of it!
Rgds
Fred
I did not know you were an alchemist as well- [Toluol is an old name for Toluene]!
Toluene was actually used as race fuel by the F1 teams in the "Turbo era" in the early 80's- I seem to remember that they had to cut it back a bit to meet the F1 octane limit. The problem with it is it needs heat to atomise [hence the difficult starting issue] and they routed the fuel flow via a heat exchanger in the exhaust to heat it up so it would atomise.
I have wondered if I can get a supply locally as heat is the least of my problems over here. I have a feeling it may be used in paint stripper or something similar. Given we probably have too much LPG in our fuel, throwing in some toluene might in fact be a good thing. 10% in the mix would take our 95 RON to something just over 96.
The best fuel you can ever get [if you could get it] would be platformate straight out of the refinery platformer unit but you would need to own a refinery to get hold of it!
Rgds
Fred
I end up being anything and everything to get the job done. Toluene is good stuff and not too expensive when bought in bulk. The really good stuff is nitropropane or propylene oxide. You need to mix toluene or alcohol with it to retard detonation. Other problem is that it will soften flex fuel lines. I've noticed that toluene seems to calm down the burning process to produce a smooth dyno graph where without toluene the torque graph would be quite wiggley. Possibly due to the EZ-K pulling advance on some cylinders.
10-20-2015, 11:55 PM
#21
Just wondering, what is 'magic' about the 9 degrees of retard that the EZK can deliver. Why 9 and not some other number, like, say, 18? If the EZK could be readily modified to pull out a maximum of (say) 18 degrees of advance, then you could set more advance than standard and then still have more safety margin than standard. I guess its not that easy or it would have already been done....?
Dave
Dave
10-21-2015, 03:07 AM
#22
Rennlist Member
Thread Starter
Just wondering, what is 'magic' about the 9 degrees of retard that the EZK can deliver. Why 9 and not some other number, like, say, 18? If the EZK could be readily modified to pull out a maximum of (say) 18 degrees of advance, then you could set more advance than standard and then still have more safety margin than standard. I guess its not that easy or it would have already been done....?
Dave
Dave
The amount of retard is programmed in the software and in stock form is applied in three progressive steps of 3 degrees each step. Presumably someone in Porsche looked at the amount needed to achieve the objective which is to produce a safe running system. From experience 3 degrees of retard can make a big difference in what happens and the max I have seen applied is about 6 degrees so presumably someone rationalised that 9 degrees was a practical margin to sustain operation and it seems reasonable to me.
The proposition I came up with was based on the fact that practical tuning suggested to me that on balance the inner 4 cylinders and 6/2 in particular, seemed to want more advance [about 3 degrees at some operating points] than the rest. To stop the knocks from taking place required pulling 3 degrees across the board but the motor was noticeably "tired" after doing so.
The dyno tells its own story - that is fine if you have access to one! Thus my proposition to try and define this point and add 3 degrees knowing that on some cylinders it will self correct and still leave you with a further margin for events such as poor gasoline. where I am there are two grades marketed- Regular and Super. The regular stuff is **** poor but it is nice to know that if push came to shove I could run on the stuff to get me home if I had to.
Rgds
Fred
10-21-2015, 08:15 AM
#23
Hi Fred
Thanks for the explanation. So if 9 degrees retard from standard is an assumed decent safety margin, and to liven things up a bit one were to set the timing to 3 degrees advanced over standard, then to retain the same total retard 'margin' 12 degrees of ezk-controlled dynamic retard would be desirable. I wonder if a modified Ezk could do this by 3 increments of 4 degrees each, 4 increments of 3 degrees each, or some other combination? Or is my musing nonsense? John Speake, any views??
Dave
Thanks for the explanation. So if 9 degrees retard from standard is an assumed decent safety margin, and to liven things up a bit one were to set the timing to 3 degrees advanced over standard, then to retain the same total retard 'margin' 12 degrees of ezk-controlled dynamic retard would be desirable. I wonder if a modified Ezk could do this by 3 increments of 4 degrees each, 4 increments of 3 degrees each, or some other combination? Or is my musing nonsense? John Speake, any views??
Dave
10-21-2015, 12:17 PM
#24
Rennlist Member
Thread Starter
Dave,
As I am aware John does not modify the coding rather he builds his system around the stock build with specific inputs being user programmable. Whether he could modify the coding I have no idea but ST2 does allow one to specify what size increments each knock step should take out [stock is 3 degrees- I tend to use either 2 or sometimes 1 degree increments].
My approach is to take out advance until signs of knocking stop and then put 3 degrees of advance back in knowing that on some cylinders the system may take some advance out under normal circumstance. This notionally leaves a margin of 6 degrees for safety. Unless you regularly drive into a region with known poor gasoline or initiates a tendency to knock [high altitude] I beleive 6 degrees of margin available should be fine but......?
Regards
Fred
As I am aware John does not modify the coding rather he builds his system around the stock build with specific inputs being user programmable. Whether he could modify the coding I have no idea but ST2 does allow one to specify what size increments each knock step should take out [stock is 3 degrees- I tend to use either 2 or sometimes 1 degree increments].
My approach is to take out advance until signs of knocking stop and then put 3 degrees of advance back in knowing that on some cylinders the system may take some advance out under normal circumstance. This notionally leaves a margin of 6 degrees for safety. Unless you regularly drive into a region with known poor gasoline or initiates a tendency to knock [high altitude] I beleive 6 degrees of margin available should be fine but......?
Regards
Fred
Last edited by FredR; 10-21-2015 at 04:28 PM.
10-21-2015, 04:22 PM
#25
Rennlist Member
I routinely set the retard step size less than the 3deg per step, like Fred. I also reduce the recovery time as the standard system takes many seconds to slowly increase to the pre knock value.
One or two knocks after tuning seems to be a good compromise.
One or two knocks after tuning seems to be a good compromise.