Engineer/math minds HELP!!
- Thread starter BlownV6
- Start date
Yes that pretty much had me set back in the seat!! I knew it was on a pass!!
Mike:biggrin::biggrin:
Your eyeballs were probably in the back of your head also. That must feel like a house pushing against your back.
Actually how it works is I have an air cylinder on the throttle cable when the trans brake is applied that cylinder extends pushing the pedal almost all the way to the floor (its adjustable). So when both cars are fully staged I push it all the way to the stop (say 1/8" and adjustable) that brings the engine up to that 3200rpm (or what ever I want it to be). There is a timer in the delay box (auto start) that will pull the throttle completely open at a predetermined time (which is also adjustable).
So on that particular run I had the throttle wide open (whats left to push open) and the engine was at 3200rpm and waiting , at .2 before the transbrake released it pulled the throttle open and was accelerating very hard. If I hit the tires with to much rpm they spin to much and everthing slows down. This launch was perfect , and I need to be able to duplicate it on a regular bassis!! Mike
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I noticed the same thing in the sim. I had to start backing the launch rpm down to control the wheel spin. At what time into the run has the throttle gone to full? I need to put that into the sim too.Actually how it works is I have an air cylinder on the throttle cable when the trans brake is applied that cylinder extends pushing the pedal almost all the way to the floor (its adjustable). So when both cars are fully staged I push it all the way to the stop (say 1/8" and adjustable) that brings the engine up to that 3200rpm (or what ever I want it to be). There is a timer in the delay box (auto start) that will pull the throttle completely open at a predetermined time (which is also adjustable).
So on that particular run I had the throttle wide open (whats left to push open) and the engine was at 3200rpm and waiting , at .2 before the transbrake released it pulled the throttle open and was accelerating very hard. If I hit the tires with to much rpm they spin to much and everthing slows down. This launch was perfect , and I need to be able to duplicate it on a regular bassis!! Mike
On a couple of passes where it was on a terror the rpm at .5 seconds into the launch was 7000. On this kind of pass it runs .95 to .96 60' and 2.70 to the 330'. Thats where Im making the guess that its shifting at around 200'. The converter is slipping a fairly high amout at this point in the run and that is throwing these numbers for a loop!! Mike
If I did my math correct..... at the 1.705 sec..... the TC slip is 11.05%
Given a 108" circumference tire grows 20% (@ say 200 mph). Assuming we are in the 125mph range.....tire growth would be 12-1/2%. New circumference would be 121.5".
Assuming the TC slip #'s are close to the same at the 1/2 shift (8040 RPM) with both trans gear sets. In reality, I would guess the T/C would slip a little more with the higher gearset (1.69) since it is under a little more load, but how much, who knows?
1.80 first gear ratio yields 121.14 mph @ the 1/2 shift
1.69 first gear ratio yields 129.03 mph @ the 1/2 shift
Those numbers are mindboggling.
I'm still playing around a little.....interesting to see what Donnie comes out with.
Interesting. I've seemed to settle at 12% tire growth at this point anyway, also.
Still having a problem getting the mph up to 194. So far only 188.
Mike, are you doing something to lower power up to midtrack and then bringing it in for the top end? It looks like I'll need to ramp a certain percentage of the horsepower in during the run. Is the methanol starting to work more after half track? Top end high speed bypass?
Blazer, Check the left column , fourth data down shows ENG/DS ratio @1.999 I believe that is the converter slip?? Mike
Correct..... then back out the 1.8 gear ratio......
Here is the log from the 194 pass at Columbus. As you can see I pussed out at 6.5 seconds and began rolling off the throttle. Check the data included!!
Donnie, I certainly didnt have any sort of tuneup for those 1/4 mile attempts so I tried to be way safe and fat. I think I actually stumbled into the fact that I havent been using near big enough nozzles all along. Mike
Donnie, I certainly didnt have any sort of tuneup for those 1/4 mile attempts so I tried to be way safe and fat. I think I actually stumbled into the fact that I havent been using near big enough nozzles all along. Mike
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I'm finding the same thing with my setup. It likes to suck up the fuel.Here is the log from the 194 pass at Columbus. As you can see I pussed out at 6.5 seconds and began rolling off the throttle. Check the data included!!
Donnie, I certainly didnt have any sort of tuneup for those 1/4 mile attempts so I tried to be way safe and fat. I think I actually stumbled into the fact that I havent been using near big enough nozzles all along. Mike
So far, at the 1.7 sec mark (8040 rpm), I'm seeing 11% TC slip too.
I'm still pumping more hp into the curve to try and match that 194 mph.
I still have a lot more work to do on the power curve, but it's starting to look like it's coming on real strong after the first half of the run. I've starting ramping extra power in starting at the 2 second mark just to start with.
Very interesting stuff.
Very interesting stuff.
Here is the log from the 194 pass at Columbus. As you can see I pussed out at 6.5 seconds and began rolling off the throttle. Check the data included!!
Donnie, I certainly didnt have any sort of tuneup for those 1/4 mile attempts so I tried to be way safe and fat. I think I actually stumbled into the fact that I havent been using near big enough nozzles all along. Mike
At this datapoint..... the 1.132 does show you actual slip #'s.... 13.2% because you are in high gear.... 1:1 terefore 1 engine RPM should yield 1 driveshaft RPM if the converter had no slip. In this case you had 1.132 engine revolutions per 1 driveshaft revolutions..... therefore yielding the 13.2% slip number.
Holy cow that thing is coupling throughout the top end. This sim can't duplicate the coupling that's occurring as it ramps in tighter to the end of the run. I'm starting to understand the shortcoming of this program to be able to duplicate this type of TC configuration. Very impressive.
I might be missing something with the power curve. I'll plug away at it a little longer.
I might be missing something with the power curve. I'll plug away at it a little longer.
I guess my PTC converter is working preety good!!! I keep talking to dusty about loosening it up a bit but I keep finding more power and that loosens it up!! Conditions were totally different from the 8000 at 1.7 seconds to to 194mph run. Like 4000' corrected altitude different. Mike
I was really hoping that was one of Dusty's units. If it wasn't, I was thinking Dusty might have some strong competition there.I guess my PTC converter is working preety good!!! I keep talking to dusty about loosening it up a bit but I keep finding more power and that loosens it up!! Conditions were totally different from the 8000 at 1.7 seconds to to 194mph run. Like 4000' corrected altitude different. Mike
With the TC coupling like that, it's hard for me to narrow down the power curve on the top end. Looking really good, though.
It appears that as the coupling progresses, the hp has to climb more to reach that 194 mph mark. Very interesting.
So far, I've had to ramp in a little over 300 hp starting at the 2.2 second mark to get the sim to match up. With the coupling that's occurring, which I cannot simulate, I have to guess that I would need to ramp in even more hp to maintain the 194 mph target.
Not a 2 to 4 percent slip number at the top end, but none the less, very, very impressive considering the amount of HP being put to it. I think any other TC would be over 20 percent.
