Basic M6 Launch Facts Illustrated
05-11-2007, 08:24 PM
#42
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Originally Posted by ilirw325
Very nice chart, just wondering what software you used to collect that data?
Also green is throttle position correct? My Z is an A4, but im just wondering, why are you letting off the throttle between shifts? especially with a strong rear? wouldnt you just want to leave the throttle on the floor and be quick with the clutch? Not being a wise *** or anything, just curious of the reason...
Thanks
Also green is throttle position correct? My Z is an A4, but im just wondering, why are you letting off the throttle between shifts? especially with a strong rear? wouldnt you just want to leave the throttle on the floor and be quick with the clutch? Not being a wise *** or anything, just curious of the reason...
Thanks
05-11-2007, 10:18 PM
#44
I am having a boggin issue with my car lately. M/t 275x50x15 drag radials dead hook me at 6500 , car pulls the wheels and tehn bogs and falls down on its face. I pulled 1.59's - 1.62's consistantly with a spec 3 and now the spec3+ grabs to hard. I would go up on air pressure but drag radials either bog or spin bad. not much in between.
I will be trying a slick soon as this should help as they will hase out while pulling where as the drag radial once spinning spin bad
I will be trying a slick soon as this should help as they will hase out while pulling where as the drag radial once spinning spin bad
05-12-2007, 10:53 AM
#45
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Originally Posted by AINT SKEERED
I am having a boggin issue with my car lately. M/t 275x50x15 drag radials dead hook me at 6500 , car pulls the wheels and tehn bogs and falls down on its face. I pulled 1.59's - 1.62's consistantly with a spec 3 and now the spec3+ grabs to hard. I would go up on air pressure but drag radials either bog or spin bad. not much in between. I will be trying a slick soon as this should help as they will ease out while pulling where as the drag radial once spinning spin bad
05-12-2007, 11:48 AM
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This seems like a good point to invite further discussion of bogging. Ideally, you would launch at your engine’s power peak and the clutch would slip just enough to maintain a constant rpm while the car accelerated with non-spinning tires. Pro-Stock cars have super-sophisticated clutches that nearly meet this ideal. Unfortunately, such clutches are very expensive and require frequent maintenance. They are not practical for us double-digit guys. So we all bog a little. My view is that if, during launch, my engine speed doesn’t fall below 4000 rpm, I don’t consider it to be a bog. If it falls below 4000, it feels like a bog. For example, my best launch, shown in my third chart, would be considered by some to be a bog.
Last edited by Gary Z; 05-12-2007 at 11:53 AM.
05-12-2007, 12:51 PM
#47
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I think the definition of "bog" is subjective.
Look at 6speedrebuilds in car vids and the car is yanking the wheels, running single digits and it sounds like it's "bogging". Same with FMS's car (long time ago).
Look at 6speedrebuilds in car vids and the car is yanking the wheels, running single digits and it sounds like it's "bogging". Same with FMS's car (long time ago).
05-12-2007, 01:51 PM
#48
I really enjoy the learning curve with 6 speed cars. I just went out to Brainerd and it took about 5 runs for me to make a decent pass. I just did 4.10s and the 15" ET Street radials (from 17" nittos and 3.42s). First run spun very bad launching between 4500-5000 just dumping it.
Second run I dropped the tire pressure from 26 to 21 and launched at 3500 trying to slip the clutch out and got real bad wheel hop, so I let off. Third run missed 3rd.
Then on the 5th run I launched with a little clutch slip at 4500 and it hooked hard. It only went a 1.80 60', but atleast it didnt spin or fall on its face.
I'm anxious to get some more weight off the nose, get a tq arm in it, and go play.
I will be as consistent as an automatic. It can be done. (Hey I've had an auto, so flame away A4 owners
)
Second run I dropped the tire pressure from 26 to 21 and launched at 3500 trying to slip the clutch out and got real bad wheel hop, so I let off. Third run missed 3rd.
Then on the 5th run I launched with a little clutch slip at 4500 and it hooked hard. It only went a 1.80 60', but atleast it didnt spin or fall on its face.
I'm anxious to get some more weight off the nose, get a tq arm in it, and go play.
I will be as consistent as an automatic. It can be done. (Hey I've had an auto, so flame away A4 owners
)
05-14-2007, 12:58 AM
#49
Originally Posted by Gary Z
My data recording software is HPTuners Scanner; the charts are created using Microsoft Excel. Yes, green is throttle position and I don’t mind that you’ve asked about my slow shifting. I'm not only slow, I occasionally miss shifts entirely. I haven't attempted powershifting out of fear of breaking the transmission. I love driving manual transmission cars, I’m just not very good at it.
Thanks for the info on the software!
Good 1/4 times and nice 60' btw!
05-14-2007, 01:26 AM
#50
Originally Posted by WS6TransAm01
My car always spins a little off the line. Sometimes a lot. I try to get one or two full tire rotations when the car leaves, that seems to be perfect.
On a side note, No offense, but those shifts take you for ever. Each shift is almost a second, that is almost 2-3 seconds your car is NOT under power. Take your second run for instance; you can see the wheel spin in the MPH spike on the 1-2 shift, but you can also see that your MPH actually decreases between shifts. You are loosing 0.5 to 0.7 seconds in your 1/4 ET's on your shifting alone. I'm not trying to be a jerk, I just think that I have a bit of experience driving 6spds and am only trying to help.
For you're own sake, you should look at the same graph, but also turn on the line for Throttle Position, after the launch it should stay steady at 100% until you cross the line. It is obvious to me looking at that graph that you are letting off during those shifts.
I don't have the files, because it was not my data logger, but my shifts average from 0.10 to 0.15 seconds, with 100% throttle position across the board.
On a side note, No offense, but those shifts take you for ever. Each shift is almost a second, that is almost 2-3 seconds your car is NOT under power. Take your second run for instance; you can see the wheel spin in the MPH spike on the 1-2 shift, but you can also see that your MPH actually decreases between shifts. You are loosing 0.5 to 0.7 seconds in your 1/4 ET's on your shifting alone. I'm not trying to be a jerk, I just think that I have a bit of experience driving 6spds and am only trying to help.
For you're own sake, you should look at the same graph, but also turn on the line for Throttle Position, after the launch it should stay steady at 100% until you cross the line. It is obvious to me looking at that graph that you are letting off during those shifts.
I don't have the files, because it was not my data logger, but my shifts average from 0.10 to 0.15 seconds, with 100% throttle position across the board.
05-14-2007, 01:29 AM
#51
I drag race a m6 vette that runs low 12s na and a 10 sec 67 camaro w a tb 400 auto and they are completly different experiences. To me the vette is way funner cuz you are enguaged the whole time and w a auto its all fun out of the hole and then your just along for the ride if your car goes straight.
04-10-2008, 10:39 AM
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A little 150 shot off the line will solve the falling on the face problem... I dead hook on some 28x10.5 with the clutch fully engaging withing .5 second and pull the tires doing so. I'm full weight and pulling 1.5 60ft's with stock bolt on LS1 with 150 shot. I launch at 4500-5000RPM and step off the clutch off the line. Thats how my car works best anyway but I believe the same concept is happening that is stated only the clutch is just being blown through in the first half a second. The Slick helps out alot on that "give" too since it acts like a rubber band off the line to sling shot the car out of the hole.
