Two Fangs Posted November 6, 2012 Author Share Posted November 6, 2012 Silly question: is it possible to get a flex fuel situation on your cars? Or of it only one or the other? There was a lot of work by the EFI Live guys to make Corvette truly flex-fuel using the fuel sensor from the Impalas, not requiring the switching of tunes. I am not sure where it ended up, but it probably landed with what timing tables were available and an unacceptable compromise. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 6, 2012 Author Share Posted November 6, 2012 Thanks to everyone who contributed to this discussion. Throttle body is off and on its way to Houston where my cousin the rocket scientist (no really, he is, for NASA) is going to see what it would take to rewind the motor to change its torque output. Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted November 6, 2012 Share Posted November 6, 2012 Thanks to everyone who contributed to this discussion. Throttle body is off and on its way to Houston where my cousin the rocket scientist (no really, he is, for NASA) is going to see what it would take to rewind the motor to change its torque output. Thats awesome and funny. I know how you feel my brother is a rocket scientist lol. He works for Orbital in Chandler. Most of what he works on is classified so he cant even talk about it with family. Link to comment Share on other sites More sharing options...
NicD Posted November 7, 2012 Share Posted November 7, 2012 Throttle body is off and on its way to Houston where my cousin the rocket scientist (no really, he is, for NASA) is going to see what it would take to rewind the motor to change its torque output. Aww shit that reminds me of the R/C car hobby days and racing "stock" motors. The kind where it was a specific amount of turns on the motor, however you could pop off the end bell and wind your own rotor with thicker wire and less turns and re-balance if you were careful. Sure it uses more current but if you did it right you could still make it last 4 minutes through a race. LOL Link to comment Share on other sites More sharing options...
Grayeagle Posted November 7, 2012 Share Posted November 7, 2012 Oh man .. talk about a blast from the past and converging technology I useda rewind armatures for my slot cars ..the big tracks were 1/24th scale. Had a '23 T-bucket with a swing arm pickup so it could wheelie ..was a plastic model I used for basically showin off.. ..my lil Chapparall was a killer on silicone tires. When I put together that 13:1 (or so) compression L-88 the starter just was not up to spinnin it much, ...so I took it apart and rewired the armature with 2 size bigger copper wire. I could hit the starter and it spun that motor like a smog motor 305 .. down side was if it did not fire, you got 4 tries and the battery was toast. As Dawg said ...did R/C for many years, had a scale spitfire (4' span) that developed elevator flutter in it's later life - was way overpowered with a .35 Enya .. in a full throttle dive after 2 years of hard landings and outright crashes now an then .. the flutter showed up. Had to rebuild the elevator and put in a bit more servo ..corrected it. It sounds like that may be what is required to more accurately control that 102mm blade -Frank aka GE Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 Throttle body is off and on its way to Houston where my cousin the rocket scientist (no really, he is, for NASA) is going to see what it would take to rewind the motor to change its torque output. Aww shit that reminds me of the R/C car hobby days and racing "stock" motors. The kind where it was a specific amount of turns on the motor, however you could pop off the end bell and wind your own rotor with thicker wire and less turns and re-balance if you were careful. Sure it uses more current but if you did it right you could still make it last 4 minutes through a race. LOL Ha ha, yeah We are going to try and change it from a 20 turn single to a 12 turn triple, LOL. Link to comment Share on other sites More sharing options...
HOXXOH Posted November 7, 2012 Share Posted November 7, 2012 Am I seeing this problem correctly now? The throttle plate is fluttering due to sudden high pressure from the turbos and it can't maintain position because the servo motor doesn't have enough power to overcome the airflow. Then the servo motor is overloaded by the pressure which ultimately slams the throttle plate to a closed position and shuts down the engine. Or I'm I still not understanding the problem? Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 Am I seeing this problem correctly now? The throttle plate is fluttering due to sudden high pressure from the turbos and it can't maintain position because the servo motor doesn't have enough power to overcome the airflow. Then the servo motor is overloaded by the pressure which ultimately slams the throttle plate to a closed position and shuts down the engine. Or I'm I still not understanding the problem? You understand about half of it. The throttle is commanded to wide open throttle. The throttle is never 100% open, in other words, the plane of the throttle blade is never actually perpendicular to the centerline of the throttle body bore. Because of this, the forced induction is able to place a load on the throttle blade. With this load applied, the throttle blade cannot maintain its commanded position and once the PCM sends a predetermined amount of current to the motor to try and correct the condition without success, the PCM shuts the throttle and takes control away from the driver. Link to comment Share on other sites More sharing options...
Desertdawg Posted November 7, 2012 Share Posted November 7, 2012 So do I get to take it for a spin after it's fixed for helping????????? At least give me a ride .... Link to comment Share on other sites More sharing options...
HOXXOH Posted November 7, 2012 Share Posted November 7, 2012 Am I seeing this problem correctly now? The throttle plate is fluttering due to sudden high pressure from the turbos and it can't maintain position because the servo motor doesn't have enough power to overcome the airflow. Then the servo motor is overloaded by the pressure which ultimately slams the throttle plate to a closed position and shuts down the engine. Or I'm I still not understanding the problem? You understand about half of it. The throttle is commanded to wide open throttle. The throttle is never 100% open, in other words, the plane of the throttle blade is never actually perpendicular to the centerline of the throttle body bore. Because of this, the forced induction is able to place a load on the throttle blade. With this load applied, the throttle blade cannot maintain its commanded position and once the PCM sends a predetermined amount of current to the motor to try and correct the condition without success, the PCM shuts the throttle and takes control away from the driver. So now my question becomes: Why doesn't the throttle plate totally open? What's holding it back? I'm looking at this from a different perspective than using brute force. Play along, it might be interesting. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 So now my question becomes: Why doesn't the throttle plate totally open? What's holding it back? I'm looking at this from a different perspective than using brute force. Play along, it might be interesting. GMs as far as my car's calibration is concerned, is different than some others out there where we can actually open the throttle a full 100%, or more. The theology behind GM's operational characteristics in my application is that by leaving the blade not all the way open, the in-rushing air can assist the throttle in closing. There have been examples of guys running the throttle blade to 110% in pursuit of more power creating a throttle hang, because the air is then pushing on the wrong side of the blade. So now, what we are doing to try and alleviate this. We are looking at changing the relation of the throttle shaft to the blade, so that the air actually assists the throttle in opening. And, we are looking at increasing the strength of the magnetic field by changing the proximity of the windings. Link to comment Share on other sites More sharing options...
Loud Pedal Posted November 7, 2012 Share Posted November 7, 2012 Very curious to see how this works out. We ended up going back to a ported 90 on the Vette because of the same problems with the 102. There is supposed to be a servo upgrade and I may give it a try, but she runs so good with the 90, I'm not sure it's worth pursuing. Link to comment Share on other sites More sharing options...
HOXXOH Posted November 7, 2012 Share Posted November 7, 2012 So now my question becomes: Why doesn't the throttle plate totally open? What's holding it back? I'm looking at this from a different perspective than using brute force. Play along, it might be interesting. GMs as far as my car's calibration is concerned, is different than some others out there where we can actually open the throttle a full 100%, or more. The theology behind GM's operational characteristics in my application is that by leaving the blade not all the way open, the in-rushing air can assist the throttle in closing. There have been examples of guys running the throttle blade to 110% in pursuit of more power creating a throttle hang, because the air is then pushing on the wrong side of the blade. So now, what we are doing to try and alleviate this. We are looking at changing the relation of the throttle shaft to the blade, so that the air actually assists the throttle in opening. And, we are looking at increasing the strength of the magnetic field by changing the proximity of the windings. Next set of questions: What's different in your car's throttle calibration vs. mine? What % does yours open? Is the opening the 88% shown on HP Tuners? Does that 88% represent a deviation from full closed to a 90* rotation of the shaft, or full closed to 88% of the rotation required to move the blade to the 90* (relative to the TB bore) position? If 88% is not enough and 110% is somehow possible, but too much, then why is 100% not possible? I have a direction I'm going with this, but want to throughly understand the problem. Especially why the 90mm TB works and the 102 doesn't. Link to comment Share on other sites More sharing options...
Desertdawg Posted November 7, 2012 Share Posted November 7, 2012 . We are looking at changing the relation of the throttle shaft to the blade, so that the air actually assists the throttle in opening. Be very careful, your forced induction assisting the open direction could result in a runaway motor if the servo cant overcome the force helping to open. About the only thing that will help within the airflow is called a spade (i.e. search aileron spade) it will assist without the ability to be over whelmed by force. Of course your also introducing turbulence and small parts into the intake so it wouldn't be my first choice. Tom, 100% open will have a greater tendency to flutter. With no air pressure on either plane of the throttle blade, the slightest deviation of air flow over the blade will cause a correction to be commanded by the PCM which will then cause an opposite deviation of air movment due to the low pressure area created by the first deviation. Link to comment Share on other sites More sharing options...
HOXXOH Posted November 7, 2012 Share Posted November 7, 2012 . We are looking at changing the relation of the throttle shaft to the blade, so that the air actually assists the throttle in opening. Be very careful, your forced induction assisting the open direction could result in a runaway motor if the servo cant overcome the force helping to open. About the only thing that will help within the airflow is called a spade (i.e. search aileron spade) it will assist without the ability to be over whelmed by force. Of course your also introducing turbulence and small parts into the intake so it wouldn't be my first choice. Tom, 100% open will have a greater tendency to flutter. With no air pressure on either plane of the throttle blade, the slightest deviation of air flow over the blade will cause a correction to be commanded by the PCM which will then cause an opposite deviation of air movment due to the low pressure area created by the first deviation. Yep! I see we may both be thinking along the same direction here. The 100% question was just to confirm if the rotation was possible, not that it was a final solution. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 Next set of questions: What's different in your car's throttle calibration vs. mine? The throttle blade reaction, which I have tuned, is different than a stock calibration. without getting into extreme detail, it opens the throttle in a more linear fashion. What % does yours open? Same as yours, 88% Is the opening the 88% shown on HP Tuners? Yepper.... Does that 88% represent a deviation from full closed to a 90* rotation of the shaft, or full closed to 88% of the rotation required to move the blade to the 90* (relative to the TB bore) position? Less than 88 degrees, but not by much. Using my keen eye and what tools I have avilable to me If 88% is not enough and 110% is somehow possible, but too much, then why is 100% not possible? It is not impossible, just impossible with the calibration tables we have available to us without getting the entire file and writing code, ala' Ed Wright. I have a direction I'm going with this, but want to throughly understand the problem. Especially why the 90mm TB works and the 102 doesn't. I am looking forward to your insight. I am looking for every opportunity to explore this and it is nice to have someone to bounce ideas off of. Link to comment Share on other sites More sharing options...
Desertdawg Posted November 7, 2012 Share Posted November 7, 2012 Jumping ahead of you testing the better windings in the servo, I think the final solution is going to be a gear driven connection between the servo and the throttle blade, probably a worm drive for the most precision and holding ability. Of course with a geared connectio you can also play with the ratio to get the torque you need out of the stock servo. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 I am currently looking at changing the relationship between the throttle shaft and blade, and opening it backwards. I like your idea, though. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 I may have to figure out how to change the way the motor counts, though.... Link to comment Share on other sites More sharing options...
Desertdawg Posted November 7, 2012 Share Posted November 7, 2012 If it works you'll be lucky. even if there is more airflow on the top or bottom of the blade your still going to have flutter but now you might also have undue stress on the servo. Changing the orientation of the surface doesnt change air flow conditions.... Ok, so how about changing the shape of the blade to affect airflow, if done correctly you can virtually eliminate flutter and the flow characteristics that cause it. Think; add an airfoil to the underside leading edge of the blade. So instead of the forced airflow pushing the bottom of the leading edge, you have created a low pressure area behind the foil creating (i.e. lift)to counteract the force pushing against it.... Stupid? yes! Just forget that and think more control with the servo through a precision geared drive. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 7, 2012 Author Share Posted November 7, 2012 Not stupid at all, and essentially what I am doing. Imagine a circle. That is the throttle body blade, now imagine it with a horizontal line in the middle of it acting as the throttle shaft. If I move the horizontal line up just a bit, and have the blade open so that the bottom rotates toward the manifold, then the side with the most surface area (the bottom side) is being affected by the incoming airflow, essentially assisting the motor instead of fighting it. Link to comment Share on other sites More sharing options...
Desertdawg Posted November 7, 2012 Share Posted November 7, 2012 I get what your doing, I just hope the motor has enough torque to overcome a full boost situation, make sure you have some way of killing the engine while testing... I hope this fix's it but I'm afraid your still going to get flutter... Maybe this plus the better windings combined will overcome the issue! Link to comment Share on other sites More sharing options...
Two Fangs Posted November 8, 2012 Author Share Posted November 8, 2012 That's the balancing act. Moving it enough, but not too much. Link to comment Share on other sites More sharing options...
Two Fangs Posted November 8, 2012 Author Share Posted November 8, 2012 Link to comment Share on other sites More sharing options...
Ted Y Posted November 8, 2012 Share Posted November 8, 2012 At least it's a hell of a ride. Link to comment Share on other sites More sharing options...
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