Landracing Forum
Bonneville Salt Flats Discussion => Bonneville General Chat => Topic started by: Flipper_1938 on October 18, 2016, 07:10:06 PM
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Anybody know what's up with the Speed Demon? It ran at Speed Week, but it looked like they pulled the plug early. I was waiting for it to make some hard passes at the shootout, but I don't think Poteet made the trip.
Is there a big issue with the new car? I want to see George make a serious attempt at 500 mph.
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Let me take a guess at why the Speed Demon team didn't run again after SpeedWeek. What's to prove, at the potential expense of less-than-great salt giving false data on what the car needs to be developed further? George's run of 442 got the team the Hot Rod trophy again, and waiting for a better course is prudent -- even if it does make some wonder why it didn't run more this year.
There's my 2 cents worth.
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George didn't think the course was safe or long enough.
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I managed to find out about an open house at george poteet's house to see the new speed demon. George said when they built the new car, they moved the fuel cell rearward from where it was in the old car ....and they were having problems pumping the fuel to the motor when the car was accelerating really hard.
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The word that was circulating down on the salt at the Shootout was that they (with their available engines) had nothing to gain, as they already held the FIA records in the applicable classes. So, why spend a bunch of money to do that on a less-than-perfect course? It was the obvious choice.
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IIRC A lomg long time ago I think Al had that fuel problem with Betsy. He moved the tank forward, problem solved.
Ron
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That was way back when Betsy had the turbo'd 392 with the fuel tank behind the engine, the wrong place for fuel when you need to move a lot of it.
Sid.
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George and Ron plan on showing the new Speed Demon at the GNRS, Jan. 27-29. At the usual place.
DW
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The new #715 car was at the PRI but was pretty much fully clothed. I didn't take any pics.
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George made it sound like the tank was behind the motor on this car.
He said on the old car, he was basically sitting on the tank. They moved the tank away from the drivers seat for safety.
He said this car went faster through mile 3 than the old car ever did by quite a bit...I don't remember the numbers but it was significant....like 30 mph faster.....and then the fueling issues showed up.
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I visited with George, Ron, & Ken at the PRI. Everything was very casual with their car on display and no real agenda, so they were very easy to visit with. They said the car is 800# lighter than the old design due to carbon body and removing the hydraulic lift system that was built in. George said he barely needs a bump off of the line and the car now pulls very well. It is interesting that they built the motor to produce 45 psi boost at sea level so that they could get 39-40 at Bonneville. They said their 3000 horsepower in the shop worked out to 2500 on the salt. Look for an A motor in the future and also see if they don't go after some gas records if they can get things to survive with 400 degree higher internal temps.
The new issue of Race Engine Technology #99 has a great story detailing the build of the Dart SBC and the components that were used in the build.
I am betting on this car to set a lot of records.
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Just found that:
https://www.youtube.com/watch?v=gkZcctxXP4E
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Feb. 26th - MAVTV Dave Despain show, 5:30 PM PST
Ron Main in person discusses Speed Demon and salt issues.
DW
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That's 7:30 PM over here in Texas, Have it set to record.
Rouse
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Not the Speed Demon, but since this topic is about George's car(s):
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"... with Y-block engine..."
Sure beats heck out of using a cookie-cutter SBC :-D
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Great article in the latest "Race Tech" magazine on the Speed Demon. Mostly about the Ken Duttweiler engine development. Pretty interesting how he "married" high tech electronic injection with "old tech" constant flow injection to be able to pass enough fuel into the engine at full chat. Another very interesting point the Ken disclosed was that they use information from the compression of the rear dampeners to estimate down force and that they have the exhaust exiting the car in a vertical direction to develop down force which they can actually measure by the dampener deflection. My thinking is that wouldn't they develop more forward thrust if they had the exhaust exit towards the rear of the car? As it is if the down force developed by the exhaust is converted into forward thrust by the tires which are dependent on the traction available from the salt so no mater how much down force the exhaust makes it would never develop as much forward thrust as just having the exhaust aimed out the back of the car. I would also think that exiting the exhaust out the top of the car as it is now would not be as aero as simply aiming it out the back of the car. But as the saying goes "They are having intercourse with this cat! I am merely holding its' head!" They are going to go really fast how ever they configure the exhaust and I will be there to cheer them on!!
Rex
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Think back to the '60's Top Fuel cars. The change from weed burners to zoomies is credited for the the ability to crest the 200mph barrier. Much like the modern fuel floppers. Limiting the header angle decreases speed and increases traction and stability. I do totally agree that out the top is an aero killer.
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I'm walking out the door -- will post the pic later, but I've got a Pork Pie picture of George and the Speed Demon steaming down the course on his 462 run, and the exhaust burble in the air is plainly visible. You can take a look at the pic and get some easy real data. I'll be back in a while.
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Last year the NHRA instituted a rule limiting how far funny cars headers could be swept back. With less downforce and more forward thrust the cars were
faster quicker but less stable. Teams had been using header changes as a tuning tool to suit the cars to the track.
The Speed Demon undoubtedly has lower drag when it isn't getting sideways.