Hey guys, I am having some issues with the car picking up from the first time run of the day. Usually 0.02-0.04 and it is making it exceedingly hard to dial. Its a monoshock dragster with a 582 on alky running little bubbas on beadlocks. I know the fluids getting warmer and thinner are probably part of it but I always take the car out and drive it around the pits and get it up to at least 150ish when I bring it back to the trailer. I usually try to pull into the waterbox around 160-165. Equal length burnouts but for example this past weekend first time run 4.81, then go up for first round dial a 4.80 and it runs a 4.79. Pay the man for buyback and go up and dial a 4.78 for second round and it runs a 4.77. So in three runs I went from a 4.81 to a 4.77 and I prefer to dial honest and not hold numbers. Any advice is much appreciated.
I think you're probably right about lubricant temps playing a role, but it sounds like water temp is the only thing you're monitoring. Oil/ATF/Diff fluid temps probably make as much difference, maybe even more. Differential lubricant, especially, is probably very hard to get up to temp idling around the pits vs an 1/8 mile run at 140mph or so.
Personally I think driving the car around to warmup should be banned, its just dangerous but I get putting load on things to help warm them up. How do you warm up the trans? I think an important part is to put the car on a stand and put the car on the chip and put some heat in the converter, 150 water temp isn't enough IMO. I get it up to 180 then shut it off and let it heat soak the engine a bit. trans temp may be your issue. Also, tune wise, if you were a little fat, as the day and sun went on you'd lean out and maybe the tune is coming closer... idk if that's right just a guess.
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Without weather data it would be tough to solve this puzzle.
Since you are on Alky I would monitor water content in the air. Relative Humidity, grains of water and vapor pressure can change the performance. Usually the first run of the day has high humidity which may be a factor.This message has been edited. Last edited by: Don Higgins Crew Chief Pro Software,
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To cold for the engine. And you need to monitor Trans temp.
Must get that between 140 - 200 my car won't change. Before 140 it's anyone's guess.
I prefer to be around 150. It's tough getting it up there for the first run. Usually hold for on brake and rev motor against brakes... In safe place you can chip it. Don't like doing that... But our track has some secluded places.
I would have to try higher water temp, especially on alky. Id go at least 170-180, just run the water pump, Next I would have to say looser convertor.
Rymo could be right with tune up as well.
We monitor oil temps before the first run, and then concentrate on water temps after. Same gauge with a switch that allows us to change from water to oil.
Good advice in this thread. I am wondering about something different. Possibly brakes or something mechanical.
Since it is a dragster I would jack it up at the beginning of the day and physically turn the back tires so you can get a good feel for the effort required. After a couple runs see if there is a difference. Maybe it takes the calipers a bit to retract completely or something else. Maybe a dumb thought but just what came to mind.
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cold oil takes more power to move. We monitor oil temp on dyno so we can compare apples to apples. I would suggest bringing engine temp up to 200, then let cool down for 1st round. Or use a oil heater.
FYI if you are using conventional oil, switch to synthetic
Without data, you’re just another guy with an opinion.
The time slips will tell where to look. Can you post them?
here's a thought....maybe it's the track coming in. I find for the most part, my car changes ET a lot more from track conditions than from weather changes during the day.
Thanks for all the ideas and suggestions. I will try them next time out and let you guys know the results. I'm thinking between getting the trans and engine warmer before first round that will help.
Is this day to night or early day to afternoon runs?????????
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Definitely some good tips on here, about possible causes. Without weather data and timeslip info, you may not get as many good pointers as you could, data is king in this game. Meanwhile, here is some advice NOT related to the car's ability to repeat:
Along with your preference to dial it hard, I take it you also prefer to win some rounds, right? So look at it this way: If your car predictably picks up .02 each pass, (at least for the first few runs), then by dialing what you now KNOW it will run, (.02 quick), you ARE dialing honestly.
But if you are serious about being competitive, you need to spend some time learning to drive the stripe. In thousands of bracket races, I do not believe I have ever seen an event won by a driver who dialed hard, and never lifted, braked, or tossed a 'tater during competition all day. (Can I get a witness, anybody?)
There are tons of good info available online to get you started, as well as do some bench racing with your pit neighbors and friends/fellow racers and discuss top-end strategies. That .02 you had in your pocket both rounds, should/could have positioned you well to turn on the win light, if your R/T's were competitive with the other guys.
Post up some more data, short times, weather info, etc. And guys on here will do their best to help you out.
Dan "Jim" Moore
Much too young to feel this damn old!!
My vote is a tight converter
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