JF fails to qualify (1 Viewer)

[ironpony]

I probably used the wrong term, they are actually measuring the cylinder temp in the header tube, if one of them "drop" they are killing the engine to avoid mixing up cylinders and blowing it up.

 

[MM]

I probably used the wrong term, they are actually measuring the cylinder temp in the header tube, if one of them "drop" they are killing the engine to avoid mixing up cylinders and blowing it up.

Every team measures the cylinder temperatures. And if one drops and it begins to mix up the others, pan pressure is created and the sensor activates the Leahy shutoff device. The measured PSI that activates the shutoff is adjustable so you can set it as low as you would like. The max setting dictated by the NHRA is (I believe) 9 psi.

 

[ironpony]

Yes i realize all the teams are monitoring exhaust temp and pan pressure. This is a better explanation then they gave on the broadcast. They made it seem like it was activated off the header temp sensor, unless JFR is trying something different???

 

[tx_trojan]

Schaffer and McCulloch have had one hell of a time getting their hands around that car this year. Very little to do, if anything, with John’s age and/or ability. Almost a direct correlation to Neff’s departure to DSR...

 

[8sec71]

Does that pan pressure switch close the butterflies? That injector went shut immediately, looked to me like he simply lifted unless the switch closes it.

 

[TooTall999]

Does that pan pressure switch close the butterflies? That injector went shut immediately, looked to me like he simply lifted unless the switch closes it.

I'm pretty sure there can't be any electronics directly affecting the throttle linkage / butterflies. I'm thinking the pan pressure switch shuts off the fuel, ignition or both.

 

[none]

I'm pretty sure there can't be any electronics directly affecting the throttle linkage / butterflies. I'm thinking the pan pressure switch shuts off the fuel, ignition or both.

If the Leahy device activates, for whatever reason it shuts the throttle, kills the ignition, shuts off the fuel and puts the chutes out.

And John S and Jason M are NOT the issue, every Crew Chief in the pits has been over there to see if they can figure it out. It's amazing to me how many people seem to think that the other JFR teams are not trying to help. Do you guys really believe that Jimmy Prock, Danny Hood, and Brian Corradi are all sitting in their lounges laughing about the guy who signs their paychecks going through this?

Even other Crew Chiefs have come over and been shown everything there is to see from broken parts to computer graphs, right now they are snake bit, and trying to work through it one baby step at a time.

AR

 

[Porkchop]

If the Leahy device activates, for whatever reason it shuts the throttle, kills the ignition, shuts off the fuel and puts the chutes out.

And John S and Jason M are NOT the issue, every Crew Chief in the pits has been over there to see if they can figure it out. It's amazing to me how many people seem to think that the other JFR teams are not trying to help. Do you guys really believe that Jimmy Prock, Danny Hood, and Brian Corradi are all sitting in their lounges laughing about the guy who signs their paychecks going through this?

Even other Crew Chiefs have come over and been shown everything there is to see from broken parts to computer graphs, right now they are snake bit, and trying to work through it one baby step at a time.

AR

Nicely put Alan.........Some people just........well lets leave it at Some people lol. Hope you are well man.

 

[TF CREW]

I'm pretty sure there can't be any electronics directly affecting the throttle linkage / butterflies. I'm thinking the pan pressure switch shuts off the fuel, ignition or both.

Yes the switch closes the butterflies

 

[T.Smith]

We've been racing top fuel for 14 years now and I still can't say with a huge amount of certainty what that thing is going to do when the throttle blades open. These cars are nothing but stress, work and issues and it doesn't take much to get you chasing your own ass. It's even worse when you have a trailer full wrecked $hit and still don't know what's wrong...like Alan said...baby steps.

 

[DrRocket]

So, is there a device that pulls the butterflies shut? Or is the throttle linkage now fly by wire?

 

[.]

So, is there a device that pulls the butterflies shut? Or is the throttle linkage now fly by wire?

PAN PSI SHUTDOWN KIT
http://www.electrimotion.com/index.htm

 

[stitcherbob]

We've been racing top fuel for 14 years now and I still can't say with a huge amount of certainty what that thing is going to do when the throttle blades open. These cars are nothing but stress, work and issues and it doesn't take much to get you chasing your own ass. It's even worse when you have a trailer full wrecked $hit and still don't know what's wrong...like Alan said...baby steps.

with the "little black book" every crew chief refers back to, it seems like all they need to do is go back to a combo that worked but didn't blow the body to splinters, no?

 

[mgty3whlr]

It could also be a bad batch of a particular part that they are using or the way it is assembled on the engine. With Alan being involved with Brittney's car, I wouldn't be surprised if he's been looking into it as well.

 

[Nunz]

baby

with the "little black book" every crew chief refers back to, it seems like all they need to do is go back to a combo that worked but didn't blow the body to splinters, no?

If only it were that simple...

 

[none]

So, is there a device that pulls the butterflies shut? Or is the throttle linkage now fly by wire?

There are different ways to do it the DSR cars have an air activated solenoid that disconnects the linkage at the injector. Look closely and you will see the air lines where the throttle cable attaches. Kalitta has an air cylinder mounted at the pedal, JFR uses something similar, but the system will in effect disconnect the pedal from the butterflies and they slam shut. In both cases the device that pulls them shut is the return spring.

Q2 at Gaineville when Doug Kalitta's car didn't leave the line I asked Jim-O what happened and he said he inadvertently activated the Crew Chief box when Doug staged, so when Doug smashed the pedal it was no longer attached to the injector.

For those who think it's a bad run of parts, the same parts are on all of the JFR cars. They don't make a different part for John than they do for Courtney. But as Tony said, once you've been through what they have you operate at an extreme caution level for a while.

Alan

 

[T.Smith]

with the "little black book" every crew chief refers back to, it seems like all they need to do is go back to a combo that worked but didn't blow the body to splinters, no?

That's not always possible, your tune up and clutch tune up are always evolving. What worked 6 months ago may no longer be relevant or possible for various reasons.

We ran a career best 3.791 at the 2014 U.S. Nationals, which to this day is still a pretty decent run. We would not even begin to consider going back to the engine tune up or clutch tune up we ran then. Our engine and clutch tune up is completely different now. I think the only thing we could look at is the clutch management flows and primary weight.

 

[TooTall999]

If the Leahy device activates, for whatever reason it shuts the throttle, kills the ignition, shuts off the fuel and puts the chutes out.

And John S and Jason M are NOT the issue, every Crew Chief in the pits has been over there to see if they can figure it out. It's amazing to me how many people seem to think that the other JFR teams are not trying to help. Do you guys really believe that Jimmy Prock, Danny Hood, and Brian Corradi are all sitting in their lounges laughing about the guy who signs their paychecks going through this?

Even other Crew Chiefs have come over and been shown everything there is to see from broken parts to computer graphs, right now they are snake bit, and trying to work through it one baby step at a time.

AR

Thank you for the clarification Alan. As I said "I think" not "I know". I'm always willing to learn something new.

 

[TSK]

Haven't the fuel teams been measuring exhaust temperatures for several years now as a method of diagnosing each cylinder's performance during a run?
During one of my many annual trips to Ennis, about 10 to 12 years ago, I heard a FC crew chief tell one of his crew to bring him a new temperature probe to replace one that had gone bad on #7. I remember thinking about how far technology had advanced to that point. It used to be teams would look at the bearings and spark plugs to see how each cylinder performed, and here was somebody asking for a new temperature probe. I can only imagine how far technology has come since then.

 

[Huge]

Haven't the fuel teams been measuring exhaust temperatures for several years now as a method of diagnosing each cylinder's performance during a run?
During one of my many annual trips to Ennis, about 10 to 12 years ago, I heard a FC crew chief tell one of his crew to bring him a new temperature probe to replace one that had gone bad on #7. I remember thinking about how far technology had advanced to that point. It used to be teams would look at the bearings and spark plugs to see how each cylinder performed, and here was somebody asking for a new temperature probe. I can only imagine how far technology has come since then.

Yes