Drive By Wire

[Bret Kepner]

Originally Posted by Bill Howell

I'm not saying mechanical tear down is not important, it just pales in comparison to the electronic checks.

Well said, Bill.

[Jeff Teuton]

There is plenty to these new cars. That from a real old car guy. But the total adjustability is what makes them a little hard to duplicate. I could go into the detail about Throttle Position, Timing Change going down the track (did I say MSD Digital), fuel pressure (critical to a EFI, a carb only needs supply) gliches, gloches, etc. Dan Fletcher went back to a carb car. Now for fact not fiction. My ss EFI 360 motor makes 10 more hp and 12 more tqe with a race 850, than a 1000 cfm Throttle Body and Fast EFI system no matter how you adjust them. A comp motor of say 850 hp will probably make 20 more. I was surprised so i confirmed that with several guru's and suppliers around the nation. Seems starting the atomization in the venturi has a better effect than injecting solid fuel at the bottom of the runner. The EFI systems of today evolved from the need for EFI on factory cars because of driveablity and emissions especially in view of the unleaded and weak fuel we run driving around. Total adjustablilty, such as the factory system that adjusts timing and fuel in microseconds makes a car run well. I think we have about 100 sensors that inform the motor what is happening while driving. At wot, most of these sensors are ignored. I'm lost. I quit for now.

[Ed Wright]

Larry, you are mistaken about taking power out effecting 60' times. If you use an MSD Digital 7 Programable box you simply back up the timing in the upper gears. That way there is also no effect on your lights, like a lot of weight would. You can do that to older carbureted cars also. No rocket science involved.

[Chad Rhodes]

Originally Posted by Ed Wright

Larry, you are mistaken about taking power out effecting 60' times. If you use an MSD Digital 7 Programable box you simply back up the timing in the upper gears. That way there is also no effect on your lights, like a lot of weight would. You can do that to older carbureted cars also. No rocket science involved.

Ed is correct. Even a carb car could have a Digital 7 (not a 7531) and adjust timing either by time or in each gear. can also pull it out at the hit to prevent tire spin ( not traction control like the 7531 box which has a slew rate rev limiter). All of this control over timing is available to the carbureted cars, as well as the EFI cars, just different ways of doing it. NHRA does need to police the MSDs as it would not be hard to disguise a 7531 as a 7530 box, and I guarantee that you could make a car repeat within several thousandths with one if you were willing to slow it down in the process. The best way to police them would be to have a laptop in tech and plug into everyone's digital box. It will pull up the model number, the cases are so near identical that it would be easy to either swap cases ,or just the decals

[Pat Cook]

With a drive by wire system, this is very doable. But to make it accurate the car would need some sort of a real time feed back to track the car as it progress down track. GPS would work, they are getting faster all the time, but what most automotive company's use for brake testing is a optical sensor that bounce's light of the pavement (they use to use a fifth wheel for this input) and the programing for this kind of a system would not be that complicated.....

That being said, in my humble opinion......just by the win column on the new cars that are using drive by wire.....it doesn't appear that anybody is using it. maybe Nitro Joe could shed a little light on the stats for new cars winning rounds or races

[Stewart Way]

Larry
I could be wrong but I read the 2009 rule different that you are. It does not rule out DBW. It states that "electronics, pneumatics, hydraulics, or any other device may in noway effect the initial throttle operation.". That is followed by DBW. The key word is initial, or first, operation. That required initial operation is the drivers foot pressing the pedal. After that motion there is no rule barring electronic, pneumatic or hydraulic. The same rule paragraph even speaks of the use of hydraulic specifically.
That said, what is not allowed except in the Super classes is the "use of....electronics to modulate the throttle after initial launch.". There is the problem, how to prove that is or isn't being done. As Ed points out, you can slow the car with the MSD , or I imagine with the on board computer, just not electronically with the throttle AFTER the initial hit. Having 100% pedal being 100% or 80% or 60% throttle position is legal, but you have to pick one and use it the whole run. Timing is a different story.
The key will be how the 2011 rule reads after the January revisions. Speak now to NHRA.
As usual, my disclaimer. "I could be wrong".

[Dean Feiock]

I think the point that needs to be made is that when using a drive by wire, the computer is running the throttle plate via a DC motor on the side of the throttle body. True in stock form, the computer uses inputs like the APP (accelerator pedal positition) to determine where it wants to drive the throttle plate position to. But it also looks at many, many other inputs to determine not only what the driver wants for throttle, but what the vehicle needs for throttle. On a drive by wire system, the PCM gives you the throttle IT thinks you need, not always what you want.

The fear is that the PCM can be used to drive the throttle plate in throttle stop like manner.
As stated earlier, if you need to slow the car down, program the PCM to only open the throttle plate 70%. No popping, no banging, no fancy ignition box, no fancy tach, just down on power. Or perhaps you cannot cut a light. Program the PCM to open the throttle 1.5 seconds after the APP sees you smash the gas on the top bulb.

I am no computer programmer. But I have been a Chrysler tech for 23 years. I am well versed on these systems. Personally, I believe it would be very easy for someone like me, who knows how the factory stuff works, to team up with a good computer guy and make a controller that could do this stuff.

[magnumv8]

As far as DBW and safety is concerned Toyota didn't have the proper defaults in their programming to eliminate a possible open throttle failure.....most OEM's run DUAL TPS sensors on the throttle blades, one to follow the throttle position as to the pedal position and the other to verify that this indeed happened and if not to throw the engine into a "limp" mode to allow control until it can be repaired.....it would not be difficult, as some have mentioned, to program this system to do anything you would like to try and the best part is it would be undetectable and if properly done impossible to find.....sort of like a "ghost in the machine"....

As a journeyman industrial machine builder, I have seen and used some really interesting and versatile micro sensors, software, and inovative programming techniques to accomplish many issues relating to automated industrial machines.....and now that sensors, computers and software are being used to control an automotive "machine".....good luck....the only limiting factor is ones imagination.....

D L Rambo....

[Sean Cour]

Originally Posted by Larry Hill

Does anyone think that Kevin Cour added 900 lbs to his car to slow it down .9 of a second to run Fletcher second round? According to "Live Timing" Cour was on a high 9.60's run @ 138+ Mph when he ran Norton first round. Second round Cour dials 10.57 and runs 10.562. Compare the two runs and '60 ft. is only down .096 on the on 10.562 run. Maybe they took 90 hp. from the engine on tune up, if they did it would not 60 ft. with a .1 of a second from the high 9.60s run. What I think happened the ECM was programmed to open throttle, at let's say 75% at the hit and run at, let's pick a number, 57% the rest of the run. His 60ft was quicker on the 10.562 run than on the 10.531 run in qualifying.

If NHRA would change the rule to "No drive by wire", a lot of the temptation would be removed. Anytime you have a computer controlling the air supply to the engine, the driver is just along for the ride. The fix would be a cable
from the accelerator to the throttle shaft on one side and a throttle
positioning sensor to tell the computer what it's position is. As opposed to
programming the computer and letting it operate the throttle plates to trace
a previous run.


Billy, I read the 2009 rulebook and you are right. Either the Fords didn't go by the rules or NHRA turned a blind eye.

For me personally, I want redundancy (a return spring) in closing the
throttle. Just in case something goes wrong.

Larry, the satellite Ford Motor Company launched into space a couple years ago, has a direct link to the CJ's PCM. Why do you think these cars are numbered? It's so the racers can access NASA's digital link through the TPS. That's why the Mustangs have fiberglass hoods. The signal would not be able to be transmitted through metal.

[Ed Wright]

First, you can move the pedal faster than the little motor moves the throttle blade(s), I get that compaint all the time from guys trying to cut lights when foot brakingate model DBW cars. Not a method you would want to use with a "1.5 second delay off the top bulb. Guys need to understand that you can't just do that without a look-up table in the software for pedal response delay. (they do not exist in OEM ECUs) maybe with some aftermarket ECU, not the factory stuff. Getting a school kid to write something for a P.C. is one thing, a Ford, MOPAR or GM computer is another. Want to close the throttle at higher MPH or RPM? They do not contain look-up tables for that either. No look-up table for that? Then you can't make it do that. Guys throwing this stuff out obviously don't do this kind of work. I get some pretty silly requests, they seem to think it's the same as programming a P.C. No college or night writing an operating system for a Ford ECU so you could add all the look-up tables to do those things. Might get a Ford calibrator to have it done.