Wasted fuel, cam timing, and injector phasing
03-11-2013, 04:57 AM
#1
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Wasted fuel, cam timing, and injector phasing
Since my experience in FI is limitted, and I haven't ever messed with fuel injector phasing, I'm curious if some of you can help me out. While testing my mid-pipe in different configurations on my car, I found that if I combined my mid-pipe with a large diameter muffler and a good CAI, I would lose a lot of fuel into the exhaust system. I wouldn't get any extra power, but I did have to increase the amount of fuel delivery in order to compensate for the fuel that was being over-scavenged into the header before the exhaust valves fully close. If you want to read more about how I tested this, you can find it between here and here.
Unfortunately for me, FlashPro doesn't provide any functionality for altering the injector phasing, so if I wanted to reduce the amount of wasted fuel, I needed to either restrict the exhaust flow a bit more OR reduce the amount of overlap in my cam timing. I wound up going with a more restrictive muffler.
However, one of my customers installed one of my mid-pipes in his car, which also has an Endyn F23C with LOTS of upgrades. While updating the tune for the new setup, he noticed that his AFR wasn't responding to his fuel adjustments as much as it should have. We discussed it, and decided that it was probably due to the mid-pipe over-scavenging the cylinders, and causing unburned fuel and air to be pulled into the exhaust before the exhaust valves close.
To prove it, he advanced his exhaust cam a bit, which reduced the overlap. The result was what we thought, and the AFR did richen up. He said power was the same at full throttle, but it was reduced at partial throttle. After setting the exhaust cam back to where it was, he tried increasing the delay in the injector phasing, which also caused the AFR to richen up. In the end, it seems that the best approach for him will be to adjust the cams to whatever gives best power, then increase delay in the injector phasing more and more until AFR quits getting any richer.
So I'm curious how many of you guys have played around with your injector phasing to reduce wasted fuel? I'm also curious to know how many have tried adjusting cam timing in order to reduce the amount of boost that "leaks" through the chambers during valve overlap. Have any of you datalogged boost level across the RPM range on the high and low cam? For example, if your boost is 5 PSI at 4K RPMs on the low cam, but drops to 4 PSI at the same RPM on the high cam.
Unfortunately for me, FlashPro doesn't provide any functionality for altering the injector phasing, so if I wanted to reduce the amount of wasted fuel, I needed to either restrict the exhaust flow a bit more OR reduce the amount of overlap in my cam timing. I wound up going with a more restrictive muffler.
However, one of my customers installed one of my mid-pipes in his car, which also has an Endyn F23C with LOTS of upgrades. While updating the tune for the new setup, he noticed that his AFR wasn't responding to his fuel adjustments as much as it should have. We discussed it, and decided that it was probably due to the mid-pipe over-scavenging the cylinders, and causing unburned fuel and air to be pulled into the exhaust before the exhaust valves close.
To prove it, he advanced his exhaust cam a bit, which reduced the overlap. The result was what we thought, and the AFR did richen up. He said power was the same at full throttle, but it was reduced at partial throttle. After setting the exhaust cam back to where it was, he tried increasing the delay in the injector phasing, which also caused the AFR to richen up. In the end, it seems that the best approach for him will be to adjust the cams to whatever gives best power, then increase delay in the injector phasing more and more until AFR quits getting any richer.
So I'm curious how many of you guys have played around with your injector phasing to reduce wasted fuel? I'm also curious to know how many have tried adjusting cam timing in order to reduce the amount of boost that "leaks" through the chambers during valve overlap. Have any of you datalogged boost level across the RPM range on the high and low cam? For example, if your boost is 5 PSI at 4K RPMs on the low cam, but drops to 4 PSI at the same RPM on the high cam.
03-11-2013, 02:53 PM
#2
I know the aem ecus allow adjustment, what are you wanting to do? tell it at what point you want the injector to spray.
Think you will use the Injector advance map.
That's all I know sorry.
Think you will use the Injector advance map.
That's all I know sorry.
03-11-2013, 04:09 PM
#3
Former Sponsor
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It's not really what I'm wanting to do as much as what I'm wanting to know. I'm not going to install an AEM EMS on my car, so I just need to live with the injector phasing I have. However, I want to know how well it works to adjust injector phasing on FI applications so that I can have a better idea how my mid-pipe will work with FI applications. My concern has been that my mid-pipe might increase the fuel that's wasted too much to justify the gains.
03-22-2013, 06:44 PM
#4
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Gernby,
in your car, when installing the larger injectors, you essentially changed the injection phase. Not sure which way, I would imagine retard it if the stock ecu logic is to inject as late as possible (to avoid waste, preignition and backfires) and by increasing the duty cycle it just starts spraying earlier so in this case you have retarded your inj phase(because you almost halved your duty cycles).
The Greedy eManage Ultimate piggy back has an option that is supposed to compensate for injector response time (and flow rate), so it might be altering the phasing in some way, but I would not know for sure. Not appropriate to you, but to someone with a GEMU maybe. (thinking again about it, it does not make much sense to be using this for the inj phase, as it is probably used to calculate the differences in flow rate between two different injectors at the same pulse width.)
So perhaps an easy way to play with phasing would be to increase your fuel pressure and proportionally reduce your pulse width to maintain afrs and just spray later and for shorter time.
hope I have been of some help.
in your car, when installing the larger injectors, you essentially changed the injection phase. Not sure which way, I would imagine retard it if the stock ecu logic is to inject as late as possible (to avoid waste, preignition and backfires) and by increasing the duty cycle it just starts spraying earlier so in this case you have retarded your inj phase(because you almost halved your duty cycles).
The Greedy eManage Ultimate piggy back has an option that is supposed to compensate for injector response time (and flow rate), so it might be altering the phasing in some way, but I would not know for sure. Not appropriate to you, but to someone with a GEMU maybe. (thinking again about it, it does not make much sense to be using this for the inj phase, as it is probably used to calculate the differences in flow rate between two different injectors at the same pulse width.)
So perhaps an easy way to play with phasing would be to increase your fuel pressure and proportionally reduce your pulse width to maintain afrs and just spray later and for shorter time.
hope I have been of some help.
02-26-2014, 09:10 AM
#5
Registered User
I'm also curious to know how many have tried adjusting cam timing in order to reduce the amount of boost that "leaks" through the chambers during valve overlap. Have any of you datalogged boost level across the RPM range on the high and low cam? For example, if your boost is 5 PSI at 4K RPMs on the low cam, but drops to 4 PSI at the same RPM on the high cam.
02-26-2014, 09:57 AM
#6
Yes the FI guys (more specifically the Supercharged guys) have experimented with reducing the valve overlap with a simple offset cam key the member Sideways introduced about a year ago. The results seem to favor it overall, with some reporting little to no gains. I think it’s a sound modification that makes sense. I’ve however stayed away from them myself at this point, just for sake of simplicity. But at $50 a key, you can’t beat it. You can spend 10x + for cams or gears to deliver much the same thing.
As far as the injector phasing, ive never messed with it. I don’t think the E manage has that capability but then again ive never explored that aspect. I believe its just as blade 954 mentioned, just for scaling from stock to over sized injectors. It does that surprisingly well, going from 360cc stock to ID 1000cc and still running like stock NA, so I never stumbled on the need to analyze it beyond that. Always great to find some added efficiency, but I figured I gave that up a wile ago when I added a SC and one that’s over doubled my WHP.
Gernby, if im not mistaken your mid pipe has some form of catalyst incorporated into it does it not? The issue with running one of these on an FI car is the longevity before failure. It will simply melt down. So I don’t think its a compatible exhaust system to incorporate on an FI car if you want to insure any kind of longevity and reliability. A strait through TP is the most logical way to run an FI exhaust system.
As far as the injector phasing, ive never messed with it. I don’t think the E manage has that capability but then again ive never explored that aspect. I believe its just as blade 954 mentioned, just for scaling from stock to over sized injectors. It does that surprisingly well, going from 360cc stock to ID 1000cc and still running like stock NA, so I never stumbled on the need to analyze it beyond that. Always great to find some added efficiency, but I figured I gave that up a wile ago when I added a SC and one that’s over doubled my WHP.
Gernby, if im not mistaken your mid pipe has some form of catalyst incorporated into it does it not? The issue with running one of these on an FI car is the longevity before failure. It will simply melt down. So I don’t think its a compatible exhaust system to incorporate on an FI car if you want to insure any kind of longevity and reliability. A strait through TP is the most logical way to run an FI exhaust system.
02-26-2014, 11:17 AM
#7
Former Sponsor
Thread Starter
My exhaust system does have an HFC core integrated into the expansion chamber. However, it is much farther away from the motor than the OEM cat, so the EGT's are much lower. I suspect that the catalyst will be less likely to melt.
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02-26-2014, 01:04 PM
#8
^^^ You need to find a test car with a 400whp+ Supercharger set up and see how long it takes before it melts or blows out. Personally I wouldn’t be interested in paying to be a test subject on your System. I’ve been on the same stock header TP and 60mm after market duel for 7 years issue free. If you can provide some good test data that shows the reliability of your system on a higher level Supercharged car, along with any power improvement over a more traditional system such as mine (which would be the whole point anyway) then you would have something. In N/A form your system is proven to deliver what you advertise.
I suggest finding a member in your area that you have a report with, dyno his supercharged car, then install your system on his car for free and dyno again, assuming it makes more power, let him use it indefinitely and see how long it last and then advertise the results. If you want to dive into a new facet of the market, it shouldn’t be unexpected that you might have to make some level of investment again. The product is already there IF it works out. If it doesn’t, you may learn something and be able to make some revisions to the current system easy enough that will, if your lucky.
I suggest finding a member in your area that you have a report with, dyno his supercharged car, then install your system on his car for free and dyno again, assuming it makes more power, let him use it indefinitely and see how long it last and then advertise the results. If you want to dive into a new facet of the market, it shouldn’t be unexpected that you might have to make some level of investment again. The product is already there IF it works out. If it doesn’t, you may learn something and be able to make some revisions to the current system easy enough that will, if your lucky.
02-26-2014, 04:32 PM
#9
Former Sponsor
Thread Starter
^^^ You need to find a test car with a 400whp+ Supercharger set up and see how long it takes before it melts or blows out. Personally I wouldn’t be interested in paying to be a test subject on your System. I’ve been on the same stock header TP and 60mm after market duel for 7 years issue free. If you can provide some good test data that shows the reliability of your system on a higher level Supercharged car, along with any power improvement over a more traditional system such as mine (which would be the whole point anyway) then you would have something. In N/A form your system is proven to deliver what you advertise.
I suggest finding a member in your area that you have a report with, dyno his supercharged car, then install your system on his car for free and dyno again, assuming it makes more power, let him use it indefinitely and see how long it last and then advertise the results. If you want to dive into a new facet of the market, it shouldn’t be unexpected that you might have to make some level of investment again. The product is already there IF it works out. If it doesn’t, you may learn something and be able to make some revisions to the current system easy enough that will, if your lucky.
I suggest finding a member in your area that you have a report with, dyno his supercharged car, then install your system on his car for free and dyno again, assuming it makes more power, let him use it indefinitely and see how long it last and then advertise the results. If you want to dive into a new facet of the market, it shouldn’t be unexpected that you might have to make some level of investment again. The product is already there IF it works out. If it doesn’t, you may learn something and be able to make some revisions to the current system easy enough that will, if your lucky.
What I want to know MOST about SC applications with my system is whether it provides the same performance benefits. I'd pay money for that, but I'm totally fine with just "guessing" that my system will increase the longevity of the catalyst.
02-26-2014, 04:39 PM
#10
Former Sponsor
Thread Starter
BTW, I don't know if I mentioned it earlier in the thread, but I actually installed 2 EGT sensors in one of my prototype systems just to make sure that the HFC was getting hot enough to ignite. I put 1 EGT immediately in front of the HFC, and put another immediately behind the HFC. I did quite a bit of testing with this to see how long it took for the HFC to ignite, and also how hot it got under the most extreme circumstances.
What I found was that it took over a minute to hit the minimum temperature required to ignite it, and NEVER came close to a temp that would damage it. The temperature of the OEM cat hits temps about 1000 F higher than mine even on a stock car.
What I found was that it took over a minute to hit the minimum temperature required to ignite it, and NEVER came close to a temp that would damage it. The temperature of the OEM cat hits temps about 1000 F higher than mine even on a stock car.
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