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Anyone know what the major difference between the different optioned strain gauges/gear **** load cells are?
For example, Speedfactory's load cell uses an external amplifier which has an adjustable **** of some sort. Not sure what the purpose is of the ****?
Then looking at other options, there are load cell shift ***** with 'internal' amplifiers. Resting rate at 2.5v, with a 0-5v spread, just like SF.
I know there is another company out there that offers strains on shifter cables, but I'm not interested in that method, and for the sake of discussion, I'd like it to be kept related to the load cell style ignition cuts that are on the shift ****...
So is there any pros/cons to having an external amplifier versus an internal amplifier?
Ended up ordering a strain with an internal amplifier. Guess discussions of strains are taboo, lol.
How about strain gauge settings?
Was thinking working with a 150ms retard cut, with a 200ms timing ramp after the cut is complete. Is that a fair basis to start off with?
Load cell is basically a strain gauge with everything built in. I built my own "load cell" for under $100 that works very well but I found something that I like better and cheaper...
That time is very long. Thats a total of three and half tenths before returning to full power. IMO WAY to long.
The basic purpose of an ignition cut is usually to make room for the inertia energy that's released from the rotating assy as engine rpm drops after a shift. After that rpm drop has bottomed out, an ignition cut then becomes counter-productive.
The downside to using an ignition cut in the 1st place is that it allows the clutch to lock up too quickly. That means not only are you adding a delay to your power production timeline, but you also suffer the maximum amount of rpm loss after the shift. Both of these things cause you to lose ET. A quicker alternative to an ignition cut is controlled slipping of the clutch. The basic advantage being that it can soften the inertia hit from rpm loss while raising your average WOT rpm both on launch and after the shifts.
The ideal drag race scenario would have you launching above maximum HP rpm, then maintaining WOT max HP rpm for the duration of the run. That's the quickest way for a given engine to produce the power required to complete the run in the least amount of time. Since that's just not realistic, the next best goal is to shoot for a high average rpm over the duration of the run. Here’s a simplified example to help explain the logic- lets say a car has the power to gain speed at an average rate of 6000 rpm per second in 1st gear. Let's also have the clutch slipping until .5 sec into the run with the tires remaining dead hooked. If the car launches at 6000 and the tires are stuck, the clutch will pull engine rpm down to 3000 by the .5 sec mark. Then rpm begins climbing from 3000 as it recovers the lost rpm, to 6000 rpm by the 1.0 second mark. What all this boils down to is that during the initial 1 second after launch, the engine's average rpm was 4500 rpm, which means the engine made 75 revolutions over that 1st second of the run.
...Now suppose that same car launches at the same 6000, but now the clutch slips just enough that the engine does not lose any rpm at all over that same 1 sec period. Now the engine's average rpm has increased to 6000, which means it made 100 revolutions during that same initial 1 second period.
...Now here's the thing- both left from the same rpm, but the launch that didn't lose any rpm actually packs 33% more revolutions of WOT power production into the same 1 second time period. If the clutch also slips just right after the shifts, you can pick up some power production there as well. You might lose some of that 33% increase due to increased slipping, but there’s a lot left over to make the car faster. Raising your average WOT rpm by balancing a smaller loss due to clutch slip, against a much bigger 33% increase in power production, can result in a HUGE net gain! It's more than a theory, many really quick cars have switched from cuts to exploiting clutch slip. If you listen closely on the starting line, you can tell who they are.
You totally lost me with that, in my setup I don't lose RPM by using a strain gauge, I retain RPM and stay in boost. I use my clutch off the line and that is it, allowing me to shift super fast without using a clutch while keeping WOT. I picked up an easy three to four tenths in the quarter mile with a strain gauge setup.
How much time would you say you saved from adding the strain?
So when I was in Tucson for an IFO event I was running high 9.29's with my strain gauge not activated because I had just purchased the strain gauge setup. With zero practice and never running a strain gauge before Joe activated my strain gauge and my first pass using it went 8.93. The next even hit an 8.88 in Phoenix but different track and conditions, so I would say Tucson was the best test between not using it and using it. Because it was the same day, track and weather and the only difference was using a strain gauge which got me 3.5 tenths faster.
So when I was in Tucson for an IFO event I was running high 9.29's with my strain gauge not activated because I had just purchased the strain gauge setup. With zero practice and never running a strain gauge before Joe activated my strain gauge and my first pass using it went 8.93. The next even hit an 8.88 in Phoenix but different track and conditions, so I would say Tucson was the best test between not using it and using it. Because it was the same day, track and weather and the only difference was using a strain gauge which got me 3.5 tenths faster.
That's a great improvement over previous time. While not shifting you have to take hand off the shifter correct?
You totally lost me with that, in my setup I don't lose RPM by using a strain gauge, I retain RPM and stay in boost. I use my clutch off the line and that is it, allowing me to shift super fast without using a clutch while keeping WOT. I picked up an easy three to four tenths in the quarter mile with a strain gauge setup.
If that were all you were using it for, bouncing it off the limiter would do just as well and be quicker yet. The problem with using the limiter is that it typically doesn't cut long enough to keep from breaking parts.
Load cell is basically a strain gauge with everything built in. I built my own "load cell" for under $100 that works very well but I found something that I like better and cheaper...
That time is very long. Thats a total of three and half tenths before returning to full power. IMO WAY to long.
I just meant as a starting point. Last thing I'd want to do is round off my dog engagement teeth during the configuring of the strain. My tuner is from the v8/rwd world and has no experience with strains, so I don't have experience to start off with. Those were just super conservative figures to start with on the dyno to work with while I work my way down to dial it in.
On a synchro trans, I was doing 100ms shift cuts. I figure on a dogbox I can get it down to 50ms without much concern. And I know with dogbox's you want to ramp timing back into ensure the dogs are fully engaged... 200ms in that regard was just purely what i'd assume to be a conservative figure which I can work down from (what's the typical average ignition ramp after the cut is applied, is my real question) once I get it on and configured right.
So when I was in Tucson for an IFO event I was running high 9.29's with my strain gauge not activated because I had just purchased the strain gauge setup. With zero practice and never running a strain gauge before Joe activated my strain gauge and my first pass using it went 8.93. The next even hit an 8.88 in Phoenix but different track and conditions, so I would say Tucson was the best test between not using it and using it. Because it was the same day, track and weather and the only difference was using a strain gauge which got me 3.5 tenths faster.
Man, that's exciting stuff to hear. Thanks for sharing your experience. What strain are you running?
The basic purpose of an ignition cut is usually to make room for the inertia energy that's released from the rotating assy as engine rpm drops after a shift. After that rpm drop has bottomed out, an ignition cut then becomes counter-productive.
The downside to using an ignition cut in the 1st place is that it allows the clutch to lock up too quickly. That means not only are you adding a delay to your power production timeline, but you also suffer the maximum amount of rpm loss after the shift. Both of these things cause you to lose ET. A quicker alternative to an ignition cut is controlled slipping of the clutch. The basic advantage being that it can soften the inertia hit from rpm loss while raising your average WOT rpm both on launch and after the shifts.
The ideal drag race scenario would have you launching above maximum HP rpm, then maintaining WOT max HP rpm for the duration of the run. That's the quickest way for a given engine to produce the power required to complete the run in the least amount of time. Since that's just not realistic, the next best goal is to shoot for a high average rpm over the duration of the run. Here’s a simplified example to help explain the logic- lets say a car has the power to gain speed at an average rate of 6000 rpm per second in 1st gear. Let's also have the clutch slipping until .5 sec into the run with the tires remaining dead hooked. If the car launches at 6000 and the tires are stuck, the clutch will pull engine rpm down to 3000 by the .5 sec mark. Then rpm begins climbing from 3000 as it recovers the lost rpm, to 6000 rpm by the 1.0 second mark. What all this boils down to is that during the initial 1 second after launch, the engine's average rpm was 4500 rpm, which means the engine made 75 revolutions over that 1st second of the run.
...Now suppose that same car launches at the same 6000, but now the clutch slips just enough that the engine does not lose any rpm at all over that same 1 sec period. Now the engine's average rpm has increased to 6000, which means it made 100 revolutions during that same initial 1 second period.
...Now here's the thing- both left from the same rpm, but the launch that didn't lose any rpm actually packs 33% more revolutions of WOT power production into the same 1 second time period. If the clutch also slips just right after the shifts, you can pick up some power production there as well. You might lose some of that 33% increase due to increased slipping, but there’s a lot left over to make the car faster. Raising your average WOT rpm by balancing a smaller loss due to clutch slip, against a much bigger 33% increase in power production, can result in a HUGE net gain! It's more than a theory, many really quick cars have switched from cuts to exploiting clutch slip. If you listen closely on the starting line, you can tell who they are.
Spoken like the username. Like someone who sits around thinking about it rather than actually doing it.
I have never seen an ET advantage in ANY shift methods... Only advantage that I have seen is less wear/ damage on dogs. I dont use timing ramp.
Was always under the impression you want to use a timing ramp after the cut to allow a smooth transition of power to ensure that the dogs are fully engaged so that they don't round off?
Spoken like the username. Like someone who sits around thinking about it rather than actually doing it.
I have a few customers that run NMRA's Ford sponsored Coyote stock class. It's a heads-up factory sealed crate engine class, they even flash the ecu's in the lanes to make sure everyone is on the same tuneup. With basically the same power/weight/tires and spec ratios, a diaphragm clutch is pretty much the only mechanical variable left to make one car quicker/faster than the others. Using the controlled clutch slip method I mentioned above to make more power, so far this year my ClutchTamer customers have set quick ET and top MPH at every race and have the current ET and MPH records, They have also brought home both winner AND runner-up hardware at every race this year with one exception.
Ford says a $6500 factory sealed Coyote crate makes 412hp@6500 / 390ftlbs@4250, min for the class is 3175lbs. Current class records are 10.075 / 131.86. According to the calculators it should take around 583-614fwhp to post those numbers, but these are sealed NA 5 liter engines running a spec tune and spec gas. Rather than allowing the clutch to pull engine rpm all the way down as far as gear ratios might suggest, they use controlled clutch slipping raise the lower parts of the rpm trace, which raises the rate of power production. Ignition cuts for clutchless shifts with locked up clutches actually slows power production.
The below graphs show "Psi" data recorded from a hydraulic throwout bearing, while using a ClutchTamer to control the release of the clutch pedal.
...The 1st graph below shows a range of incrementally increasing amounts of "initial hit" (controlled by the ClutchTamer's inner "initial hit" dial), basically giving you the ability to instantly release the clutch pedal to a precise point in the pedal's travel. This is important because it gives you the ability to temporarily withhold or "dial out" some clutch clamp pressure, which would otherwise pull the engine down too quickly...
...The 2nd graph below shows a secondary range of pedal release rates (controlled by the ClutchTamer's outer "delay" ****). This gives you the ability to precisely and independantly control the clutch pedal's travel rate beyond the "initial hit" point, which is important because it gives you the ability to separately control how long the clutch slips...
Not all my customers run Mustangs, there's some pretty fast fwd turbo Honda guys too.
02-24-2017, 12:58 PM
Difference between strains and load cells
