I have been reading that with a window switch , the n2o should be turned off 200 rpm before the shift, even in an automatic. Is this true?
Also, those of you who launch in 4x4, when do you turn off 4x4?

Thanks, the install is booked for Thursday.

John

Launching in 4wd on the spray is not a real good idea.

That front axle isn't designed to take the extra torque that your gonna be putting down.

And the transfer case chain will be taking the brunt of that also. 1 broken chain = + $$$$$$$$ to repair.

If you have the electronic transfer case 4wd will not disengage under power. You will have to lift your foot, otherwise it will stay in 4wd until you do.

Been there tried that.

Better off getting a set of drag radials and lauching in 2wd at the strip.

As far as spraying through the shift, thats ok as long as you don't hit 4th gear under the spray or go over 6000 rpm's.

Set your shifts for 1-2 @ 5950 and the 2-3 for 5850. Rev limiter set @ 6100. DO NOT SHIFT MANUALLY WHEN USING YOUR N2O !!!

If you screw up and hit the rev limiter, you will regret it. Good way to turn your engine into a decorative doorstop...

Hitting the rev limiter shuts off the fuel rail..instant lean condition. Very bad..

So wouldn't it be better if he sets his rev limite too 6500 George, then there is no possible way he would hit it.

quote:

Originally posted by Bettsie:
I have been reading that with a window switch , the n2o should be turned off 200 rpm before the shift, even in an automatic. Is this true?
Also, those of you who launch in 4x4, when do you turn off 4x4?

Thanks, the install is booked for Thursday.

John

Spray it in 4x4. Nobody I've heard has broke the drivetrain doing this. Even Hemidup is running low 11's in a 4x4, supercharged 6.4L Hemi and spraying with the stock axles and driveshafts / transfer case. This is your big advantage. Otherwise the truck is just a slow and heavy 2wd pickup.

As for the rev limiter, it only closes the throttle blade on my '03, not the fuel, but other years may differ.

Johnny I wouldn't go that high, the stock toner ring has been known to come apart above 6300.

Chrysler states the stock bottom end is balanced to 6300 rpm max. Forget where I read that a couple of years back.

Maybe I should claify something here also. If your running a RC 4x4 which is 800 lbs lighter that makes considerable difference in the stress on the driveline.

I have over 200 dragstrip runs on my truck and so far so good running the way I do. And I don't think that a 5825 lb 4x4 that pulls 1.78 60' times in 2wd is doing bad at all.

Just my opinion is all.

This message has been edited. Last edited by: D500,

Yeah I have heard that to George, not saying he has to spin it that high just set it there so there was no chance at hitting it when the truck shifted at 5950.

quote:

Originally posted by Johnnyk416:
So wouldn't it be better if he sets his rev limiter too 6500 George, then there is no possible way he would hit it.

IMO, yes it would and that's exactly what I do and as an additional safety net a low fuel pressure switch to close the nitrous solenoid is also strongly recommended.

I also use a progressive nitrous computer which really helps launching in 2wd in my 4x4. FJO Mini Controller....it's the cats meow and only $225.00.

Just my .02

Rickster

Hey Everyone,

Thanks for the great info. What about stopping the happy gas before the shifts?
BTW George, I reprogrammed my SC flashpaq for your recommended shift points, 6300 rev limit and 87 octane tune. Do i have to get retimed every time out or is the 87 tune retarded enough?

Thanks,
John

You should be good. The pcm holds the tune you loaded until you change it.

As long as you are running the 4306 colder plugs and 93 octane gas with the 87 tune no worries there.

As for spraying through the shifts it shouldn't be an issue. Thats how I run mine.

quote:

Originally posted by Bettsie:
Hey Everyone,

Thanks for the great info. What about stopping the happy gas before the shifts?
BTW George, I reprogrammed my SC flashpaq for your recommended shift points, 6300 rev limit and 87 octane tune. Do i have to get retimed every time out or is the 87 tune retarded enough?

Thanks,
John

I run mine through the shifts always.....50k miles and no problemo....!!!!!!

Rickster

i have run countless bottles through my truck and rarely have i done it in 2 wheel drive. all last summer, i'd stall it up to around 3200 and spray right off the line in 4 wheel drive, and that was running sticky 305's on all corners, so i didn't spin much (60ft times in the 1.5 sec range). yes the front axles aren't that big, but at any given time they are handling only 25 percent (each) of the engine's power output, which is further reduced through the torque converter in the automatic transmission in front of your transfer case. spray through the shifts and hit the rev limiter if you want, it's NOT A FUEL CUTOFF. you DON'T go lean when you hit it. fuel cutoffs are used for rev limiters on vehicles with a cable operated throttle body. since ours is drive by wire, the pcm closes the throttle blade however much it needs to in order to keep the engine speed at the set rev limit. if anybody doesn't believe me, hook up your flashpaq or predator and datalog your throttle position, then run your truck up in first and hit the rev limiter, and you will see.

overall, my opinion on the subject is this: you, just like me, are running nitrous on a stock motor. a motor with cast pistons and a cast crank. a motor which has been shown to be prone to piston breakage, even without nitrous/FI. if you are willing to run the risk of pushing stock parts to do things they aren't designed to do, be ready to spend some coin if things go south on you.

my truck is my daily driver but i run the shit out of it. i didn't start modding it because i wanted to make it last, i modded it because i wanted to make it fast. you hear a lot of talk about our trannies being junk and our rotating assembly being crap, but when it's left stock and used for what it's meant for, you don't see many problems. i'm not sure if my truck is a freak or not, but the abuse i've put my motor and tranny through is insane, 3200-3400 stall 4wd launches on the bottle, i've spun that motor to 7,000rpm, and just in my day to day driving i routinely hit 6000+.

back to your original question, just be as hard on it as you want. if you want to launch in 4wd, do it. spray through the shifts if you want. just remember that the truck isnt meant to deal with that stuff, and broken parts = money. as D500 said, the transfer case chain isn't cheap, so keep that in mind spraying in 4wd. tranny rebuilds aren't cheap either, and its hell on your 2nd gear clutches when they're forced to apply under the stress of a nitrous-huffing motor ripping at 6000rpm.

Thanks harleyc16. A great answer.

John

quote:

A great answer

if your gonna play,sooner or later,your gonna pay.

nitrous is like a hot girl with herps...so tempting but you know youll get burnt lmao