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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Variation in 60ft to 330 timeGo | New | Find | Notify | Tools | Reply | |
| Variation in 60ft to 330 time | Login/Join |
| DRR Trophy |
Went racing today in my new to me (2015 Diamond Dragster). This is my first year with this car, or any dragster for that matter. We have picked away and worked on dialing in the combo throughout the season. The last three passes today were all very close et wise. All passes in the same lane: 1.126 1.125 1.125 3.218 3.218 3.226 4.671 4.671 4.681 4.997 5.004 5.008 137.96 135.35 137.56 I am trying to figure out why it fell off from the 60-330 on the last pass. The weather changed very little, 150 ft DA. I am on gasoline.... Does anyone have any insight? I went -.001 red the last pass, but wouldn't have won the round since the car slowed down. Looking to improve it if I can. | ||
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DRR Pro |
that appears to be a variance in the track,but being dialed 5.03 you would have had a good chance of winning honesty is the best policy,insanity is a better deffense 1.036, 6.16@ 224 | |||
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DRR Trophy |
150ft of air for gas will do exactly what you saw in ET difference. That car is deadly, as are all Diamonds. I would not worry about it one bit, or put the car on alcohol so it doesn't move as much day to day with the air. Nick Craig 1971 Camaro Split Bumper 376ci LS3 | |||
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| DRR Sportsman |
you were on the verge of a jet change. 1 jet leaner should have put you back to your earlier 60/330 time. However, that's some deadly consistent times. | |||
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| DRR S/Pro |
I don't agree with the others, .008 change with the same 60' is too much assuming its not the track. Lots of things could cause this, I'd start with checking your shifter and shift rpm to make sure its doing the same on each run. | |||
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| DRR Trophy |
Interesting feedback on this. I am thinking of switching to Alky next season. I am wondering if it is a gas thing where alky would be more stable. I see other cars not move all day on alky. Just how deadly is Alky? I could play with the jets and go down a size. I honestly just didn't think of that. Easy to do, and may be the minor tweak I am looking for. On the shifting, it is setup to shift of time through the pro-cube. I have always went off rpm in the past, but this car was setup this way when I got it. I just adjusted the delay box to get it where it needed to be for my combo. To be honest I am not sure what to do to switch it over to Rpm. It has a KR relay board setup and a grid.I saw where the jumper is. Do I just need to switch that over to the other color jumper? I have been curious to try it. I am not complaining, this is the best car I have ever had. That said, had I turned the light green, it wasn't going to beat the .009 pack in the other lane. Not when you run .018 off the dial (was dialed 4.99 that pass). This isn't the first time it moved split time from 60-330. I need to see if I can get that figured out and tighten it up some more. | |||
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| DRR Top Comp |
It depends on what you consider shifting the same. Shifting on time, the shift is made at the same spot on the track with the rpm at which the shift occurs dependent on traction from run to run. Short shifting below peak power on time can make up in consistency for tire slip dependent on the additional rpm closer to peak power, the same as tire slip can hurt consistency shifting on time at peak power in the same fashion. If you're shifting at peak power it is advantageous for consistency to shift on rpm. It's a no brainer. I'd be more interested in the other side of the ticket, more specifically with the mph there in to be 9 total. | |||
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| DRR S/Pro |
I'd recommend shifting on rpm unless the track is bad, then time is better IMO. Alky and gas are both good when setup right. I have rum both and I feel gas is more predictable than alky. To me if doesn't matter if the car moves around as long as its predictable when doing so. | |||
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DRR Trophy |
Have you looked at the data graph from the grid? It's not spinning a little on the shift is it? Maxx Levell If you're gonna be a bear...be a GRIZZLY! | |||
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| DRR Sportsman |
My guess is your dropping back into the stall of the converter. I was doing that and it would vary in that split. Raised RPM and thing was dead on after that move. Increase shift RPM about 400-500 and I bet it tightens up. Another thing if not that is it might be spinning on shift sometimes.  Configuration: 3350#, 582 C.I., 60 - 1.24 1/8 - 5.53@ 126MPH 1/4 - 8.73@ 159MPH  3700#+210lb driver, FULL interior, through mufflers, 10.5 tire. 60'-1.333 (IN 4000ft DA! Joisy Math excluded; 1.25sec using JOISY MATH.)  1/4 - 9.60@144MPH | |||
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| DRR Trophy |
You guys are definitely giving me some things to think about. I was pondering switching to alky due to cost and the cooling benefits. There is an advantage there in late rounds for sure. I have no drive shaft sensor so I don't know how I can tell with the grid if it is spinning on the shift. I will call KR tomorrow and ask them what I have to do to switch it over to shift off RPM. It can't be that hard, I wouldn't imagine. MPH on the other car with the .009 pack was 107. The converter is an interesting thing to think about. I literally pulled the motor trans and converter out of the door car, changed the tail shaft and output shaft and went racing. I don't know much about the black magic that happens inside one of them to say if that was a good or bad thing. Anywho, here is a screen shot from the grid file showing what it typically looks like. I over laid those three runs and don't see any glaring differences. Battery volts are all the same, nothing really stands out. The thing that gets me is this car has shown me variation on that split time before.  https://imgur.com/a/qGpAXuI all 3 layed over top one of another  https://imgur.com/MeRvuP1 I can not figure out how to share pictures on here, so click the links please | |||
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| DRR Top Comp |
The gassers I've worked with which were good, we rung em out a little more so than you're doing here. The torque seemed to me more peaky than what I'm used to with alky working on mine (broader torque). 6300-6400 stall might be a hair tight, not terrible though. The converter does look to be tugging on the engine a little much after flash stall at the hit though. Although it could be it needs more gear. I dunno, but the gassers I've worked with ended up with loose inefficient converters and gear, worked pretty good like that (consistent). I wonder if a 8" converter would be the hot ticket or if it could get away with more gear? What tire? What gear? Using an equation I can figure for how efficient the converter is now, looks a little snug on the ticket and graph. If you're gonna switch to Alky I'd suggest just put a 6500 8" converter in it. Shift on time around 7200- 7300, it'll be mean.  | |||
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DRR Pro |
I would not mess with it. It will turn win lights on now  | |||
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| DRR Sportsman |
To change your shift from the pro cube to the grid, you need to change the shift option on the K&r wiring board. If you have the super duty board, there are two plugs that are wired together. Unplug the one that’s plugged in and plug the other one in. On the standard board it’s a switch that you flip. When you do this it makes sense to verify that the grid is connected to the wiring panel. I would then set the grid to shift at 2500 or so and start the engine and rev it up to make sure it does in fact shift. Then change the RPM in the grid to your desired shift rpm. | |||
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| DRR Trophy |
4.10 gear and MT Big Bubbas. It is over tired and under geared for my combo. I don't care about being the fastest, just want it to print tickets. Thanks for posting my graph, I appreciate it. Thanks for the info on the KR board. I will try that change. I know it has two different jumpers looped together. One for time and one for RPM. I looked at them last night. It must be the super duty board. I will swap it over to RPM and play with the grid. I'm not sure if he had the shift light or the output switch setup to shift off rpm. I may have to try both and see. I don't want to make real big changes, but feel like it shouldn't have moved like it did. Rpm shift is an easy change to make and try at the track this weekend. | |||
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| DRR Top Comp |
On Imgur it says give your post a title,,,, Click on "get share Links" It's the BBcode you want Corey to share photo's.  It's fine down track 23% slip at the stripe. The dip is because it was built for a car 500-600 lbs heavier is all and could use a little effective gear. That dip won't hurt it as much or be quite as steep if you make the switch to methanol down the line, it'll work good.This message has been edited. Last edited by: Mike Rietow, | |||
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| DRR Top Comp |
Another thing you can try if you come to the realization the dip is hurting your consistency. We went down this road to slow a 5.90 car down to run 370 Pro Tree 6.50 index. It rattled off 4 runs in the day within a couple thou on the early incrementals with no prior testing. This is shifting to high gear on time 3 tenths after transmission brake release. It'll slow the ET but won't hurt the MPH. The only reason ours is down a couple mph here is I was pulling 14 degrees timing simultaneously 3 tenths after TB release to kill as much et as I could for the 6.50 index. When the sun went down and humidity came in we knew we'd be holding more than 7 hundredths (alky fuel droplet size). Try this if you don't care about ET, I'd say it'll go 5.20 137. I bet it'll work good (consistent) the way your car is effectively geared. Especially Alky but gas too if you find the dip is hurting your consistency on gas.  This message has been edited. Last edited by: Mike Rietow, | |||
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DRR Pro |
Lots of good ideas however you are smashing atoms and overthinking this. Its the track and it would be what id expect for the weather change. You need to dial appropriately for the change. Gas will move more than alky but like mine yours looks predictable so there is no issue there, did u compare other comparable cars with yours those runs? I would start worrying about shift points tires or anything. Your car is good, just need to dial different Ryan Fasano 2014 Byron Overall Track Champion Byron's actual elevation is 730' because that matters more than winning anything ever.... | |||
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| DRR Pro |
Ryan Fasano 2014 Byron Overall Track Champion Byron's actual elevation is 730' because that matters more than winning anything ever.... | |||
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| DRR Pro |
When shifting on RPM with Grid you want to use the Shift Light (Yellow wire) and NOT the Output Switch (Brown / White wire) RPM feature. The Shift Light is more accurate for RPM shifting than the Output Switch RPM feature. | |||
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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Variation in 60ft to 330 time
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