boosting up off the line

kmkdiesel

kmkdiesel

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Oct 1, 2007
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I have always pulled with manual trucks, so havent had any problems boosting up off the line with them in the last 4-5 years, but this year I am pulling my mega in 2.6, first hook didnt know how the tranny would hold so I take it easy, and just barely powerbraked and didnt build and boost and took off, turbo spooled up just fine. I have boosted up in 4low in the past and snapped my front driveshaft out playing in the truck, so I am alittle worried about boosting up off the line. what psi are you guys boosting up to, and any of you broke a front driveline. In my 12v pulling 2.6, manual i was boosting to about 25psi coming off the line, but with this automatic not sure what to do. Here is a vid of the first hook. Real short track, pan was dropping at the 100' mark and 1st place was only 9' ahead of me at like 173', my truck also didnt hold gear and upshifted at the end of the pull when I was getting ready to downshift and killed the truck. Cant here much on sound the ole lady was to noisy lol and not the best vid

[ame="http://s226.photobucket.com/albums/dd159/kmkdiesel/?action=view&current=115.mp4"]115.mp4 video by kmkdiesel - Photobucket[/ame]
 
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I usually go for around 15psi I let it roll just a little as Im doing it because Im worried to about snapping a ujoint or shaft in the front but so far so good. It seems the more boost I get off the line the better it pulls.
 
revolutiondsl said:
I usually go for around 15psi I let it roll just a little as Im doing it because Im worried to about snapping a ujoint or shaft in the front but so far so good. It seems the more boost I get off the line the better it pulls.
Click to expand...

i have seen alot of people do that, now that you mention it, the 66 spools super fast in my truck, so it doesnt take much to spool it at all, Ill probably try powerbraking alot harder next time I pull, and try boosting up to at least 10 psi, in 4 high i have boosted up to 25 psi many times with no problems just worried about 4 low.
 
I usually go for 20-25psi, if its muddy 10-15psi. Last pull i tried for 30psi launch, and lost my front ring and pinion.
 
NEsmoker said:
I usually go for 20-25psi, if its muddy 10-15psi. Last pull i tried for 30psi launch, and lost my front ring and pinion.
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with a manual or auto, from the looks in your sig, your a manual for sled pulling, which from what I have seen boost alot higher off the line because there slipping there clutch to take stress off the front drivelines, i never had a problem boosting up as much as possible with my manual pullers I have had
 
[ame="http://www.youtube.com/watch?v=KcCIsO-wPTI"]http://www.youtube.com/watch?v=KcCIsO-wPTI[/ame]

Thats how I've always seen Troy do it down here in our mid-mo association
Not sure if the duramax motor makes a difference, I've never seen anyone else start like him and he always hauls it off the track
I don't think it would work for p-pump motors
 
The 99 is a georend auto. It stars pushing threw the brakes around 3k rpm and thats rite around 25 psi and that when i let off the brakes and the charger goes full bore in a second from that point, but i have a 3.0 charger.
 
cumminsman315 said:
http://www.youtube.com/watch?v=KcCIsO-wPTI

Thats how I've always seen Troy do it down here in our mid-mo association
Not sure if the duramax motor makes a difference, I've never seen anyone else start like him and he always hauls it off the track
I don't think it would work for p-pump motors
Click to expand...

It is all truck setup, I have seen dmax pullers leave at 3000, cummins leave at 4000 and some cummins leave at 1800, convertor stall, turbo size, even gear selection play a part in it.
 
I know the 30spline stock front axles will only hold about 10psi with my set-up. Anything after that and its a gamble weather it'll hold. I've broke 3 front shafts in the last 10 hooks LOL
 
I cant leave leave any higher then about 18psi but I have a fairly tight converter. Im running a smaller 2.6 S400. It really starts pushing hard around 15 then I let it go. I shift to 2nd and lock it up about as fast as I can then go to 3rd
 
Chris, Can I assume the snapping sound off the line at the Burton pull was a front shaft?
 
MOSER 35spline and a detroit. The spline in the carrier stripped out from going down the track. Axle broke off half in the carrier and half out
 
So i have an automatic DTT built, how do i pull with that do i just shift it manually or how i'm gonna pull today and not sure how to.
 
I put mine in 4 low, drive and OD off and let it eat... seemed to work alright for me but I am no professional.
 
Yea thats what i was gonna try just wanted some other ideas, since ive never done it before. thanks
 
I have a vid of mine, "03 first pull" on here. I obviously didnt boost up on it too hard, but I will build atleast 10-15lbs next time, and not get beat by the same Dmax next time haha.
 
ok in 4wd low lock, it only got to 1300 and wouldn't climb, i could move the pedal up and down and sometimes it almost went up a little more maybe1350 but still no boost. Could that be my apps sensor or and ecm problem or something. also a side note i did some launchs and it shifted realy hard and didn't build boost until almost 3rd gear.
 
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