Langdon 345mph

[none]

Alan no disrespect was meant I just thought you misread what I said.

I agree, I think you are not understanding my thought or maybe I am not explaining it clearly. So the clutch locks up at XX seconds and the RPM hits the limiter at 900 feet, if they delay the lock up .010 seconds now the RPM hits the limiter at 1000'. keeping power and MPH up. If you pull timing at 900 feet the car is going to lose MPH. Now as seen this is NOT the best scenario for ET.

The rev limiter doesn't know or care what the clutch is doing. It knows and cares about the engine speed. So it you slip the clutch and the engine gets to the limiter, it loses power, you need to keep the RPM under the limit and you don't hold the engine speed down by letting it run through the clutch.

It is my understanding that on both the 345 runs the engine dropped or fluttered a cylinder at the step, then picked it up (which is pretty unusual) that delayed the full acceleration for a split second and that delayed the engine getting to the limiter. I think Brian called it a "Happy Accident" in Florida.

Alan

 

[ironpony]

The rev limiter doesn't know or care what the clutch is doing. It knows and cares about the engine speed. So it you slip the clutch and the engine gets to the limiter, it loses power, you need to keep the RPM under the limit and you don't hold the engine speed down by letting it run through the clutch.

It is my understanding that on both the 345 runs the engine dropped or fluttered a cylinder at the step, then picked it up (which is pretty unusual) that delayed the full acceleration for a split second and that delayed the engine getting to the limiter. I think Brian called it a "Happy Accident" in Florida.

Alan

OK let me try a different approach and I agree with you 100%. I am using generic numbers here so
At 2.75 seconds the clutch is in full lock up, pulls the engine down to 6500 RPM it takes till the 900' mark to hit the limiter, at 900' it pulls timing and "slows" the car down
So if you delay the full lock up till 2.8 seconds now it will hit the limiter at 1000' and not effect the timing, keeping the MPH up.
To me it becomes a simple math problem, RPM, Gear Ratio, Tire Diameter, if I can hit the 1000' at 7900 RPM instead of pulling timing and hitting it at 7800 RPM I am going to go faster. Now to do this I would say you are going to have to launch softer which by dropping a cylinder it did, however. you are going to go sacrifice ET which is not a winning combination.

I noticed something similar when I ran S/G back in 1980ish if the car spun a little I would get better MPH but lower ET. I would use this a a "tuning" tool back then. A few of us would put a cassette recorder on the passenger side and listen for the engine RPM and what it was doing, that was our data recorders back then, LOL.

This is a hood scoop I ran back in the day and it was before PS had them. Dad and I built it from aluminum sheet 2 pieces.
He thought it would be aerodynamic based on his aircraft experience. It was mounted and sealed to the 6 pack, the hood was 3 layers of fiberglass cloth with a styrofoam core, IIRC it was about 6-7 lbs. That car was a daily driver in late 70's early 80's and ran 10.50's all day. Flat towed to the track on weekends about 45 minutes each way, if you had an open trailer you were a baller. Another interesting fact, Scott Shafiroff rebuilt the 6 pack and tuned this car, thats when it went 10.50. his first shop was about 2 miles from my parents house.
Boy I got that way off topic.

 

[none]

Love the car!!!!!

You are assuming that the engine speed at lock up is constant. It is not.

If you delay the lock up you will not be pulling the engine down as far. The sooner you can lock it up the lower the RPM will be at lock up. If you push the lock up out, the engine stays at a higher RPM because it doesn't have the load to pull it down.

If you have a car with a clutch, hold the engine at a steady 4000 and let the clutch out slow, they engine stays near the number, but when you let the clutch out fast that's when it pulls the engine down.

Alan

 

[GumbyWVU]

Love the car!!!!!

You are assuming that the engine speed at lock up is constant. It is not.

If you delay the lock up you will not be pulling the engine down as far. The sooner you can lock it up the lower the RPM will be at lock up. If you push the lock up out, the engine stays at a higher RPM because it doesn't have the load to pull it down.

If you have a car with a clutch, hold the engine at a steady 4000 and let the clutch out slow, they engine stays near the number, but when you let the clutch out fast that's when it pulls the engine down.

Alan

Man you guys are way over my head but I think the conversation is truly interesting!

So I have to ask - was this 345 an anomaly or might we see it more often in the next year, given the right weather temp/altitude? Have we began crossing a mechanical threshold?

 

[mick]

Man you guys are way over my head but I think the conversation is truly interesting!

..... was this 345 an anomaly or might we see it more often in the next year, given the right weather temp/altitude ......

i believe b. husen mentioned on one of SGMP broadcasts, he felt the 340's are very much approaching
the limits as per existing rules ....... IMO we'll see plenty more 340's, but will be interesting to see if the 345-350 zone is attainable.
i think it will this year. twice.

 

[Cliff]

I thot 350 was a pipe dream. Now I think that we could very well see it this year.

 

[twostep]

I thot 350 was a pipe dream. Now I think that we could very well see it this year.

I'm not so sure. It took 26 years to go from 330 to 340 and the 340+ speeds, in my opinion, are more due to punting the mud flaps than intermittent dropped cylinders affecting the timing retard. Could have happened on Shawn's two 345 passes, I suppose, but there's now been quite a few 340+ passes being logged by cars that never posted speeds much over 335 when the flaps were in place.

345 to 350 is a big, big step. And should I be proven wrong I'll bet it only happens one time.

 

[mick]

would be interesting to know, if all the nitro CC's were questioned, 'on an almost perfect run with no dropped holes,
no tire shake, and no hazing of tires, how much e.t. do you think has been gained by the removal of the flaps?'
would some name an e.t.? or would some say little or nothing? i wish nhra would let teams experiment with vortices on body
and/or wings. (not ground effects)

 

[GumbyWVU]

i believe b. husen mentioned on one of SGMP broadcasts, he felt the 340's are very much approaching
the limits as per existing rules ....... IMO we'll see plenty more 340's, but will be interesting to see if the 345-350 zone is attainable.
i think it will this year. twice.

Funny, I was thinking very similar - perhaps at the new Potomac Nationals track, at Sonoma, or at Pomona. My thoughts being their nearness to sea level and if the weather was just right and the track likewise. Yep we might see another 345.xx

 

[J. S.]

would be interesting to know, if all the nitro CC's were questioned, 'on an almost perfect run with no dropped holes,
no tire shake, and no hazing of tires, how much e.t. do you think has been gained by the removal of the flaps?'
would some name an e.t.? or would some say little or nothing? i wish nhra would let teams experiment with vortices on body
and/or wings. (not ground effects)

I find it quite interesting that NOBODY removed the so-called "mud-flaps" for decades. As innovative as these crew chiefs supposedly are, no-one thought to give that a try at some point? They were just thought to be indispensable - absolutely mandatory - until they weren't? What other things are basically "monkey-see, monkey-do" (Everyone else is doing it, so it MUST be good) on these cars currently, that could be done away with to improve performance?

 

[Just Paul]

I thot 350 was a pipe dream. Now I think that we could very well see it this year.

When the tracks got shortened to 1000', I would have bet everything I owned Tony Schumacher's 337mph 1/4 mile run in 2005 at Brained would forever be the fastest run ever.

 

[stitcherbob]

All I know is that nitro engines love a load, they make more power under a load. Pretty sure Dale Armstrong said that.
And the upcoming 350mph will come from the A.J. camp.....

 

[ironpony]

I am of the thinking we are reaching the fastest speed possible with the limitations of RPM, Wheel Diameter, Gear Ratio. The variable I can not nail down is the tire diameter at the finish line, based on some guesses we are right at the max limit of MPH. Each inch in diameter is about 7 MPH so in theory a new tire vs a used tire could be a big difference.

 

[TSK]

How soon before NHRA imposes changes in hopes of slowing the cars?
I have a hard time believing Goodyear, NHRA, and NHRA’s insurance company, aren’t getting a bit nervous seeing these incredible speeds.
The centrifugal stresses and download from the rear wing have got to be getting close to the tires’ limits.

 

[ironpony]

How soon before NHRA imposes changes in hopes of slowing the cars?
I have a hard time believing Goodyear, NHRA, and NHRA’s insurance company, aren’t getting a bit nervous seeing these incredible speeds.
The centrifugal stresses and download from the rear wing have got to be getting close to the tires’ limits.

I am standing by my information of 340 MPH, now you know there is a margin of safety and 342, 343 is not going to make them come apart, now that we have seen 345 I am going to say "they" are going to do something.

 

[LoPony]

I’m betting they wait till another tire comes apart, or they hit 350.

 

[65 Goatboy]

I am of the thinking we are reaching the fastest speed possible with the limitations of RPM, Wheel Diameter, Gear Ratio. The variable I can not nail down is the tire diameter at the finish line, based on some guesses we are right at the max limit of MPH. Each inch in diameter is about 7 MPH so in theory a new tire vs a used tire could be a big difference.

Currently reading Warren Johnson's biography. He would scrounge up used tires to increase his top speed and the first to go over 200 mph in a PS.

 

[ironpony]

Currently reading Warren Johnson's biography. He would scrounge up used tires to increase his top speed and the first to go over 200 mph in a PS.

IIRC he paid a kid to do burn outs outside his shop to loosen the tires up too.

 

[stitcherbob]

IIRC he paid a kid to do burn outs outside his shop to loosen the tires up too.