ECU rule thoughts
- Thread starter C. Ludwig
- Start date
Chip.
Thanks for adding fuel to the fire. But can I ask you a question? Or serveral?
Do you really think you are done? With the amount of dyno time you did, it sounds like quite a simple fuel and ignition map, do you belive their is no room to improve?
What kind of Dyno? Did you do adjustmets for top HP, or did you adjust to improve the total area under the curve?
Is any of this going to need to change when you change headers? Fuel?
Stock computers generally bow out a Full Throttle. An aftermarket computer doesn't have to. Can the gains be great? It would depend on how you measure great. But if you and a buddy race the same cars and he gets 1% more power/torque under the curve than you, you lost.
Thanks for adding fuel to the fire. But can I ask you a question? Or serveral?
Do you really think you are done? With the amount of dyno time you did, it sounds like quite a simple fuel and ignition map, do you belive their is no room to improve?
What kind of Dyno? Did you do adjustmets for top HP, or did you adjust to improve the total area under the curve?
Is any of this going to need to change when you change headers? Fuel?
Stock computers generally bow out a Full Throttle. An aftermarket computer doesn't have to. Can the gains be great? It would depend on how you measure great. But if you and a buddy race the same cars and he gets 1% more power/torque under the curve than you, you lost.
Ok, now see, here is where I am trying to get down to earth with this question. I know you just threw out the 1% figure, but let's say an E36 can make an additional 1%. That's a smidgeon above 2 bhp. My answer is "so what?" There are so many little things in an engine build if you don't get them exactly right, even an experienced builder could lose more than that in a engine build. Or any of a number of things. Differences in drivers can make a bigger difference.
So what is the real number? What is the real world difference over a remapped factory ECU (not a stock mapped one)?
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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Joe Harlan
New member
George, I would challenge to do a little research on your own here.
http://www.motec.com/definitions.htm
I am not certain you can have an general estimate of performance gain. Peak HP gain has never been the issue as far as I am concerned.
http://www.motec.com/definitions.htm
I am not certain you can have an general estimate of performance gain. Peak HP gain has never been the issue as far as I am concerned.
Banzai240
New member
WOT doesn't have as much to do with winning races as you guys are making it out too. Anybody can hold their foot down on the gas on the straight. Usable HP and were you get it is what wins races... You know, the times when you are balancing the car on corner exit and using something OTHER than WOT... Think about it for a moment... The ONLY time the computer goes into WOT mode, is when the throttle-position-sensor (TPS) is signalling it to do so. Otherwise, you are in whatever other map curve the ECU has selected. THIS is where the finer granularity comes into play. WOT maps have little to do with this mode, and this is where you are going to spend a descent % of your lap...
If it were Drag Racing, you guys would have a point, but it's not...
Go do some research on what you can do with one of these things (MOTEC), and it might open up some ideas on what you might be able to do, and not to do, with your modified stock piece...
A modified stock piece can be good, but a MOTEC, et.al., can be made to be GREAT...
Think about that 2hp you mentioned above... In a class like ITB or ITC, that's worth about 38lbs of weight... In ITA or ITS, about 30lbs...
How much would you have to spend on wheels, or other weight savings measures, to get that much weight off the car?? Or, perhaps a better question... how much would it be worth if your car was at it's minimum weight, but had the benefit of having the additional power to accelerate as if it were 38lbs lighter, assuming only a 2hp increase at any point in the curve???
As an example... assume that an car makes 150hp at the flywheel and is spec'd at 2380lbs. That's a 15.86 wt/pwr ratio. 152hp would make that a 15.66 wt/pwr ratio... 0.2 better... I think that's significant... Now, imagine being able to fine tune your system to have that kind of gain over the entire map? To be able to finely optimize EVERY point...
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Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
[This message has been edited by Banzai240 (edited November 19, 2004).]
If it were Drag Racing, you guys would have a point, but it's not...
Go do some research on what you can do with one of these things (MOTEC), and it might open up some ideas on what you might be able to do, and not to do, with your modified stock piece...
A modified stock piece can be good, but a MOTEC, et.al., can be made to be GREAT...
Think about that 2hp you mentioned above... In a class like ITB or ITC, that's worth about 38lbs of weight... In ITA or ITS, about 30lbs...
How much would you have to spend on wheels, or other weight savings measures, to get that much weight off the car?? Or, perhaps a better question... how much would it be worth if your car was at it's minimum weight, but had the benefit of having the additional power to accelerate as if it were 38lbs lighter, assuming only a 2hp increase at any point in the curve???
As an example... assume that an car makes 150hp at the flywheel and is spec'd at 2380lbs. That's a 15.86 wt/pwr ratio. 152hp would make that a 15.66 wt/pwr ratio... 0.2 better... I think that's significant... Now, imagine being able to fine tune your system to have that kind of gain over the entire map? To be able to finely optimize EVERY point...
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Darin E. Jordan
SCCA #273080, OR/NW Regions
Renton, WA
ITS '97 240SX
[This message has been edited by Banzai240 (edited November 19, 2004).]
Bill Miller
New member
George,
There are folks out there running $30+/gallon fuel to get those extra 1-2 hp. You keep dismissing small hp gains as insignificant. Also, as others have pointed out, it's really the area under the curve, not the peak value.
Even if you got no more hp from a MoTec system, but you broadened your powerband by 1000 rpm, it would be a significant advantage.
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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
There are folks out there running $30+/gallon fuel to get those extra 1-2 hp. You keep dismissing small hp gains as insignificant. Also, as others have pointed out, it's really the area under the curve, not the peak value.
Even if you got no more hp from a MoTec system, but you broadened your powerband by 1000 rpm, it would be a significant advantage.
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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
Joe Harlan
New member
Thanks Bill,
If I knew how to communicate I could have said that well.
Joe
If I knew how to communicate I could have said that well.
Joe
John Herman
New member
George, if its any consolation, I understand what you're trying to get at. Unfortunately, I don't know that I can ask your question(s) any better to get a better understanding/response.
I'm with George on this one. If you're not at WOT, then you either need to be, or you have more than enough power at that time. If you improve the power at that throttle position next time (assuming you're fully at the limit) you'll need even less gas. The tires can only handle so much force.
If this is what people are buying MOTEC for I'm amazed...
Grafton
If this is what people are buying MOTEC for I'm amazed...
Grafton
My data aq showed that in my Rx7 I was at 100% throttle over 85% of the time at WSIR. In the Vee it is probably closer to 95% (no DA yet). That is about 12% of the time during braking and 2% during shifting, 1% where my foot and brain had different ideas.
As far as George's argument I see the logic. If you aren't at full throttle because your tires/chassis can't handle the application of more power, then when you make more power you are going to have to give it less throttle netting the same HP.
But now you have the same HP at less throttle, so even with the same HP at full throttle you will be making more power everywhere in between.
Who has dyno runs at 3/4 throttle anyways?
[This message has been edited by Quickshoe (edited November 19, 2004).]
As far as George's argument I see the logic. If you aren't at full throttle because your tires/chassis can't handle the application of more power, then when you make more power you are going to have to give it less throttle netting the same HP.
But now you have the same HP at less throttle, so even with the same HP at full throttle you will be making more power everywhere in between.
Who has dyno runs at 3/4 throttle anyways?
[This message has been edited by Quickshoe (edited November 19, 2004).]
shwah
New member
It has a nearly stock motor, it has stock carb or fuel injection system (and computer), it has better shocks/springs/anti-roll bars, it has less weight than stock and lots of safety equipment. Again, I enjoy the class as it is, but it is my opinion that the allowance of any engine control that fits in a certain box is too far for IT cars.
Unfortunately I don't really know. I know that sucks but I'm really far from an expert on this subject.
I am one of those guys who does not want to cheat. I believe that the majority of my competitors are those kinds of guys too. So with the old rule I like to think that most cars were 'clean'. I am sure some of them were not, and I have no idea how to fix that - but I imagine that those people will do, or are doing other things beyond the rules (intentionally) becuase they place less value on the integrity of following the rules, and more value on winning plastic trophies.
There is a big difference between interpreting a rule differently, or doing something illegal out of ignorance and actively trying to cheat without getting caught. I think (maybe hope) that the vast majority of IT racers are in the former rather than latter category. If you look at this without assuming that everyone will be cheating then enforcement does not become as big of an issue in my mind (I am not saying it is not required).
Of course having said that...The more I think about it, I guess If I were smart I would be pulling for a more open rule. If I could run a MAP based Meqasquirt system, I could ditch the massive restriction that is the CIS air meter in my intake tract. OTOH when you consider that plenty of people have seen 160+ whp with this system on modified engines it makes you wonder if the fuel injection system would make much difference with stock head, valves, cam.
Chris
[This message has been edited by shwah (edited November 19, 2004).]
Thank you for that lead-in. Let's talk about this for a moment. You're balancing the traction at corner exit. You're at part throttle. Why part throttle? Because WOT will deliver more power to the tires than they can use and you will lose traction. So what good does having 2 or 20 more hp at part throttle do for you? Nothing, because you CAN'T use it. The only thing that will make a difference is throttle tip-in response. Think about it.
But if you cannot use the power on tap already at part-throttle, what good is another X hp?
I looked at the web site Joe posted. The only thing I see that you can do is traction control. But since the ECU gets no chassis info, it's pretty rudimentary. The only thing you can program it for is to keep the rpm from climbing at too fast a rate. In some situations that could even be a disadvantage. This is not full-on road racing traction control with feedback from all four wheels.
Some of the Motecs can use a wideband O2 sensor. But that is ilegal in IT unless the car came with said wideband O2 sensor.
Data logging is already legal.
Why? Because of the finer resolution in the map points? If so, how many hp is generated from this greater resolution. Unless I misread that website, a stock Nissan ECU has 256 rpm points. With an 8000 rpm redline, that is a point every 31.x rpm. Again, I know I don't have experience with this, but I'm dubious about how much hp can be found between the points, especially since all ECUs that I know of interpolate between the points.
Thirty pounds. That's finer resolution than we can make in estimating a car's potential. I understand your point. And many people spend thousands chasing 2 hp. But is it truly significant. Botch one corner per lap, just a little, and you've lost more than you would gain from 2 hp. In a lot of cases, 2 hp is within the margin of error of a dyno or the error window of the person running the dyno.
I'm not saying 2 hp is nothing, but it's hardly worth screaming about.
I'll say again, I AM and always have been against the wording of the current rule that allows the Motec to be used. I don't think it fits the class philosophy. What I'm trying to get down to is how much real world difference does a Motec make over an equally well remapped factory ECU? I further have said that I think the real advantage of the Motec is the ease of adjusting it (tuning). The other advantage is that it offers a solution for some cars that otherwise have no aftermarket solution.
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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Our engine application, Ford Contour/Mercury Mystique, never came from Ford with any aspirations other than dependable transportation. Testing in 2003 we hooked an OBD scanner to the car on track and learned it went open loop, retarded timing and increased fueling at WOT. While these changes were happening, the car fell on it's face and, really...no kidding, other competitors would hit us in our butt....
The stock system is a VCT on exhaust only that maintains a large overlap at low RPMs (reducing emmissions) and a small overlap on midrange and higher (maxing torque). Great for a 4-door grocery getter, but not anyting any self respecting IT competitor would ever consider for sprint racing. That was our lot and the engine was codified by the CRB in 2001(?).
The ECU rule and the "or replace" language was a God send for us. Where before the stock rev limiter kicked in at 6900 RPM we now pull cleanly to 7300. And the Ford techs designing the system, knowing the engine would never see anything other than 6900 did not work on tables beyond that figure...why bother? It will get the kids to soccer practice just fine.
Am I avoiding the direct question....Yep. Lets just say that it's good for 400 RPM and peak Hp is several times the 1-2 HP increase. With a Cd of .62 our lap times at Summit and Mid-O are about a second quicker. It's a bunch.
Will it work for you in the same way? I think most of the modern IT entries were designed and sold as performance sports cars or sports salons. Their design teams envisioned something much different than the mini-van motor we are required to run. I don't know, but I'd expect that you typically would not see the same gain we have. You will see some... and the benefits don't stop there. Go to Colorado and throw an overall fuel factor decrease of -15% at it, it will probably like it. Takes about 3 minutes. Check plugs (or EGT's or wide-band O2) and see you are still fat, go to -18%. You won't miss a session trying to adjust the fuel pressure regulator or change out a resistor in the coolant temp circuit. Running too hot? throw a litte more fuel at it and turn on the fan at 160. Another 2-3 minutes.
I've rambled. Thanks for listening. Cheers.
Chip Bond
The stock system is a VCT on exhaust only that maintains a large overlap at low RPMs (reducing emmissions) and a small overlap on midrange and higher (maxing torque). Great for a 4-door grocery getter, but not anyting any self respecting IT competitor would ever consider for sprint racing. That was our lot and the engine was codified by the CRB in 2001(?).
The ECU rule and the "or replace" language was a God send for us. Where before the stock rev limiter kicked in at 6900 RPM we now pull cleanly to 7300. And the Ford techs designing the system, knowing the engine would never see anything other than 6900 did not work on tables beyond that figure...why bother? It will get the kids to soccer practice just fine.
Am I avoiding the direct question....Yep. Lets just say that it's good for 400 RPM and peak Hp is several times the 1-2 HP increase. With a Cd of .62 our lap times at Summit and Mid-O are about a second quicker. It's a bunch.
Will it work for you in the same way? I think most of the modern IT entries were designed and sold as performance sports cars or sports salons. Their design teams envisioned something much different than the mini-van motor we are required to run. I don't know, but I'd expect that you typically would not see the same gain we have. You will see some... and the benefits don't stop there. Go to Colorado and throw an overall fuel factor decrease of -15% at it, it will probably like it. Takes about 3 minutes. Check plugs (or EGT's or wide-band O2) and see you are still fat, go to -18%. You won't miss a session trying to adjust the fuel pressure regulator or change out a resistor in the coolant temp circuit. Running too hot? throw a litte more fuel at it and turn on the fan at 160. Another 2-3 minutes.
I've rambled. Thanks for listening. Cheers.
Chip Bond
Ok, I can understand this one.
Chip, don't forget, I'm not talking about 1-2 hp over a bone stock ECU. I'm talking about over and above what an equally remapped factory ECU can make. I strongly suspect you're comparing to a bone stock ECU (but certainly could be wrong). It's quite possible the additional 400 rpm yields a greater hp increase, but most IT spec engines don't make additional hp above the stock redline. They just get more range to work with. Can you tell me if my guess above is correct? You don't have to reveal any secrets.
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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Geo
Fair question. The cam phasing issue on our engine may contribute 50% or so. We did not spend a lot of time on the dyno with permutations. I cannnot speak to any gain from a "remapped" to a "replaced" ECU.
We never had any success with remapped ECUs (though several were provided by persons within the Ford loop).Driver feedback was always that it was a tad better in midrange, but nothing up top. No hard dyno numbers were obtained. Understandable, since it was the WOT tables when it went open loop. And we did not find anyone who would take a crack at the tables. Nor did we see any help with resistors.
Please keep in mind I'm here from a unique perspective. We are production and our spec line overrides some IT build specs. Issues here affect us, but maybe not as directly as the rest of the IT community. Twice in the last 5 years rulings have made all the Caterhams illegal...now...right NOW and in any form. It's not that the CRB intended it. More, its an oversight where we fell between the cracks..because we are working two separate rule sets. And, brother, if you want complexity, well...
I'm off the box now.
Best
Chip Bond
Fair question. The cam phasing issue on our engine may contribute 50% or so. We did not spend a lot of time on the dyno with permutations. I cannnot speak to any gain from a "remapped" to a "replaced" ECU.
We never had any success with remapped ECUs (though several were provided by persons within the Ford loop).Driver feedback was always that it was a tad better in midrange, but nothing up top. No hard dyno numbers were obtained. Understandable, since it was the WOT tables when it went open loop. And we did not find anyone who would take a crack at the tables. Nor did we see any help with resistors.
Please keep in mind I'm here from a unique perspective. We are production and our spec line overrides some IT build specs. Issues here affect us, but maybe not as directly as the rest of the IT community. Twice in the last 5 years rulings have made all the Caterhams illegal...now...right NOW and in any form. It's not that the CRB intended it. More, its an oversight where we fell between the cracks..because we are working two separate rule sets. And, brother, if you want complexity, well...
I'm off the box now.
Best
Chip Bond
ShelbyRacer
New member
And thank YOU for that lead in...
I program my own ECU's. Granted, not for any IT cars, but for something much more interesting.
Point is, transition *response* is much more important than horsepower. Even with the typical mods allowed in IT, the stock computer can make mistakes on transition. This is because of a lower number of waypoints and BLM (block learn module or mode) regions. On transition from one region to another, you can have, um, hiccups at times. If this happens coming off the turn while applying throttle at traction limit, your results may vary
Most of all, there's the issue that all stock ECU's require closed loop to function even reasonably well at part-throttle, and if you're running leaded fuel or something exotic, your O2 sensor may not be, shall we say, reliable. Mapping solid forms on all open loop mode allows the car to run very consistently (even if it may not be optimized at that moment) and therefore make it be subject to the driver, rather than vice-versa.
With stock style ECU's, emissions, part-throttle driveability (with stock parts only), and component longevity were the primary concerns, so closed loop is the best choice. Under racing conditions with modifications, the lack of processing power, low number of modifyable blocks, and the interconnection of all feedback systems are all limiting factors, and using an aftermarket ECU allows you to take control of the situation, rather than having to work against the instincts of the car system.
Make more sense?
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Matt Green
"Ain't nothin' improved about Improved Touring..."
[This message has been edited by ShelbyRacer (edited November 19, 2004).]
Actually Chip, you've provided some excellent insight. In some ways, what you've just provided makes me much more open to believing the Motec does have a place in IT. For cars that you can't get a remapped ECU or one that works worth a damn, the Motec (or something similar) may be the only option. Either way it's a really tough call.
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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
Indeed it does. Thank you Matt.
I understand throttle response (transients) are an issue and figured a remapped factory ECU could be mapped to work nearly as well. Perhaps not. I get what you're saying.
Care to take a guess at the hp differences between a stand-alone and a well remapped factory ECU, driveability aside? It also sounds like you're saying that in open loop there is more than one map. Is this correct? If so, can you explain or if not can you correct me?
I know the Motec is more powerful (not talking ECU, talking mapping and processing) than factory ECUs. The real question for me remains just how much additional power can be made over an equally well remapped factory ECU. I mean, basically you have air, fuel, ignition advance, and in some cases, cam timing to work with. Thanks for hanging in there.
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George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com
ShelbyRacer
New member
Well, again, I'd say it's not so much of a power issue, as much as it's a consistency issue. While there is only one real WOT map, it can change on the fly on a stock setup from changes to the long-term block learn numbers. Now, this adaptability can be good because if the stock system is tuned properly, it will actually try to keep the car in optimal tune. Problem is, if conditions vary drastically from, say, qualifying to racing, the car will be trying to adapt while you're racing, and as it does, it will change data points. If they don't all change at the same rate (and the NEVER do), you'll get weird reactions from the car on transients, which is just the time you don't want the car to be unpredicatable.
One other issue I didn't think to mention is that early ECUs will run a 2D table map with scaling modification of values, while I would assume MOTEC runs a 3D surface map. With this difference alone, you're talking about a system that operates much more smoothly. You need three axes because your lookups are TPS vs. MAP vs. RPM. The 3D tables make a surface plot that allows the ECU to direct read a value, while the old systems use multiple 2D tables and make the ECU jump back and forth comparing values.
Again, I'd say it's not about power. but to put it in those terms- I'd say both systems are capable of making a smooth curve which makes. lets say, 200hp at a certain point. Difference is, on a day where conditions are not perfect, the MOTEC may make 195hp at this point and be happy with that (actually, it just won't care). The stock ECU will attempt to get you back to where you were, but it doing so, might make 190hp one time, 196hp the next time, 194hp the next time, 201hp the next time, 198hp the next time, etc. and by the way, that imagine that 194-201 jump happening while feathering the throttle at the limit of traction while coming out of the infield onto the bowl portion of your typical oval/road course track...
Oh, and now imagine having a turbo car that does that through a corner, but the difference now being 250hp-290hp since the boost curves are also affected...
DISCLAIMER- I am very aware of the difference between torque and HP, but since the question was asked in terms of HP, that's what I used.
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Matt Green
"Ain't nothin' improved about Improved Touring..."
I know that this strand isn't about carbs but part way through Matt's last explanation, it struck me that anyone with OE management systems who thinks that advanced technology systems aren't fair should really sympathize with the "carb guys" argument against FI tweaks being allowed in the first place.
I think it's a safe summation to say that the difference between a plain-Jane OE system (diddled or otherwise) and a really good race system, boils down to "faster and more often." Stock injection's advantage over a carb is that adjustments happen "faster and more often," too.
This doesn't mean that I don't think a more liberal rule might be a better answer, if we are truly as constrained as it seems, of course.
K
I think it's a safe summation to say that the difference between a plain-Jane OE system (diddled or otherwise) and a really good race system, boils down to "faster and more often." Stock injection's advantage over a carb is that adjustments happen "faster and more often," too.
This doesn't mean that I don't think a more liberal rule might be a better answer, if we are truly as constrained as it seems, of course.
K