Competition ? about 4x4 launches...

[WDimig]

ive had the chance to go up to the track recently and race the truck, and i did a 4x4 launch everytime, but i was being easy on the truck thinking i might break something. i have the upgraded transmission with the billet input shaft, but im worried the i might break my transfer case or worse. when i get off the line i shift out of 4x4 after 2nd gear shift, my ? is should i do this or leave in 4x4 down the whole track?? will i hurt something if i do leave it in? and finally do you think i can launch with about 10-15 psi without damaging anything?? i know its racing so anything could happen, but im tryin to do the best i can without breaking parts. thanks



wes

 

[Morse]

Run 4x4 the whole way. . You shouldn't have any trouble launching hard at your current power levels. .

 

[Rhondasway]

First, you have a billet output shaft too, right? You can break those pretty easy without a ton of hp. Otherwise you're set up just right. Every truck is different, but here's my experience:

I've put about 60,000 miles on my truck (bought used), with well over 200 4x4 launches at 10-20lbs boost. Last year I was launching at 15-18lbs, shifting out of 4WD right after the 1-2 shift, and locking my converter. I am still running the stock (as in 'never been replaced') U-joints, driveshafts, front and rear diff's, and light duty transfer case, with 129,000 miles.

I am of the opinion that you should shift out of 4WD unless you find traction loss happening after that point. On my newly rebuilt motor, if I shift out I end up breaking the tires loose mid-track, so I now run 4WD the whole way. I just always figured, "Why do any more wear and tear than necessary to get the job done?"

The one thing to be wary of when launching with boost is your actual stage time. When you are on your converter for long periods of time (like you're waiting for your opponent to stage), your transmission can get very hot and you can do damage. I've done a few seconds (nervously), but you should watch your gauge and follow your transmission person's advice as far as that goes.

BTW, what times did you run?

Good luck, RR

 

[WDimig]

rhonda - no i dont have the billet output shaft , thats one of the things that im concerned about breaking if i launch hard, the best time i ran up at the track was a 15. 2, but everything about that run sucked, i have no idea what happened at the line, because my reac, time was a 1. 14 :--) boy was i asleep , and i only did a mild 6-8psi launch. also im not running a converter locker which im sure would help my time by a few tenths of a second. i need to get up there and make some more passes and dail her in. i didnt know what to expect the first time, but im a bit more confident now, and im gonaa try some harder launches, and get my reac. time better.



wes

 

[aharrow]

I was under the impression that when you launch in 4wd even when you shift out of 4wd that the vacuum still keeps the front axle locked while under heavy load does anybody know different? thanks Aaron

 

[Rhondasway]

Aaron, I was/am under that impression as well, so I've been surprised. I had lifted off the throttle one time which explained that run, but it has happened again. Maybe my equipment is finally wearing out... :-laf

Wes, racing takes a lot of practice; you just have to get in front of the lights. You will get your best 1/4 mile times based on a strong 60' time. You can keep this time at its best by shallow staging. This means that you pre-stage, build your boost (or RPM), then eeease into the second set of lights (full stage).

At your level, you should probably launch on the second yellow on a Sportsman tree. Don't be afraid to red light either unless there's something at stake. You'll still get your time slip, and you'll have a better idea of where you need to be.

The lockup switch is an effective tool, but it is hard on trannies. Unless you're real serious and willing to take even more risks, you may want reconsider.

Keep it up!

 

[WDimig]

thanks for the advice and positive encouragement rhonda!, i might get a chance to go back up there this friday, dunno yet, but if i do ill try to shallow stage and see what i can do. you def. right about getting that second light for the sports man tree, i think with a good reac. time and a nice launch ill be down in the mid, maybe low 14's. that ill make my truck the quickest truck up at the track that ive seen so far . there soo much tuning that i need to do. im trying to get my truck up to a pump shop to have them max out my pump, that with the right amount of timing and ill be somewhere close to 500hp i hope Oo.



wes

 

[JVolpe]

Just remember that Reaction Time does not have any effect on you run times. R/T matters only against the other guy/bracket racing.