Launch / Neutral drop - JeepForum.com

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post #1 of 20 Old 04-07-2011, 09:30 AM Thread Starter
08Hemiwk
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Launch / Neutral drop

So i was messing around in my WK Hemi today and found that if i rev the engine in neutral she only gets to 4k which i found odd (I come from manual cars, this and my ZJ are my only autos). I dropped her into drive and just about snapped my neck, four wheel drive burnout and all. Is this something that should generally be done? My instinct is no, but I know very little about this truck so for all I know the drivetrain is strong as all hell.

My ZJ doesnt even shift if i try that, stays in neutral til i let it back under 1500rpm.

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post #2 of 20 Old 04-07-2011, 09:46 AM
Craft95ZJ
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I couldn't tell you how many drive shafts I've twisted/broken u joints due to doing this stunt. Its fun and all but don't make a habit of doing so.

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post #3 of 20 Old 04-07-2011, 10:32 AM
scotro95
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Quote:
Originally Posted by Craft95ZJ
I couldn't tell you how many drive shafts I've twisted/broken u joints due to doing this stunt. Its fun and all but don't make a habit of doing so.
Yea I did it the other day too, she launched hard but now my trans is acting a little funny, you can really hear it engaging, so save yourself the thousands of dollars and drive it the way it's supposed too.
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post #4 of 20 Old 04-07-2011, 11:30 AM
meep
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it is common for ecu's to limit unloaded rpms to below redline. it actually puts more tension (pulling, not pressure) on the conrods with no load because there's no pressure on top of the pistons.

When you take a spinning engine, a 30+lb TC (with fluid) and drop it into gear, something has to give. It's hard on a driveline.

I had a weird experience the other day-- I snap-stomped the throttle to pull out from a standstill. It actually immediately snicked into 2nd until I was rolling maybe 5-7 mph and THEN dropped to 1st -- then back to 2nd as expected. torque management? My 2wd 3.7 WILL scuff my oversized REVOs at launch.

I've never really snap-stomped it. Usually press into it (easier on the driveline). I can only guess it was programming to prevent overtorque.
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post #5 of 20 Old 04-07-2011, 11:34 AM
BonesWK
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neutral drop


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post #6 of 20 Old 04-07-2011, 11:55 AM
overboostin
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^lol

When I'm racin I make sure to neutral drop it, then start in L, then go 2, 3 and drive. That way, its kinda like I have a manual. Adds like 15hp that way.

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post #7 of 20 Old 04-07-2011, 04:05 PM
90grandoneer
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I believe the out of gear rev limit is 3000 RPM. With the DS tuner you can raise it. I have mine set at 4000 RPM. What everyone else says about being hard on the drivetrain, too.

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post #8 of 20 Old 04-07-2011, 06:08 PM
Smokey28173
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neutral dropping is seriously hard on the engine like meep said something has to give and if you do that too often you are gonna find out whats stronger the tranny or the engine

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post #9 of 20 Old 04-07-2011, 06:25 PM
kkuty
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Quote:
Originally Posted by Smokey28173 View Post
neutral dropping is seriously hard on the engine like meep said something has to give and if you do that too often you are gonna find out whats stronger the tranny or the engine
I vote engine.
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post #10 of 20 Old 04-07-2011, 06:32 PM
Smokey28173
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probally the transmission engines are typically built pretty rough and tough. transmissions ........ not so much

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post #11 of 20 Old 04-07-2011, 08:16 PM
DAHEMI
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this is abuse you don't want to subject your vehicle nor your wallet to! good luck!

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post #12 of 20 Old 04-07-2011, 08:18 PM
theskier74
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Quote:
Originally Posted by BonesWK View Post
neutral drop

my thoughts exactly

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post #13 of 20 Old 04-07-2011, 08:24 PM
sal-XK
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Oh my god this conversation is not happening. Neutral drop a trans is probably one of the worst things you can do. It doesn't surprise me anyone would have trans issues after that kind of stunt and If you don't have issues you will or at least took years off the life of your trans. Your engine can take it but everything else is crying underneath your Jeep. You would be lucky to just throw a shaft or a U-joint. You're lucky your trans didn't throw parts all over the street which I have seen done.
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post #14 of 20 Old 04-07-2011, 09:12 PM
tjkj2002
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If you want to launch hard like that install a trans brake and save thousands of $$$'s in broken parts.Just make sure you add a monster trans cooler with it's own dedicated fan.

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post #15 of 20 Old 05-26-2014, 04:50 PM
Jeep4tw
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I have a 99 jeep xj and I drop from N to 1/2 and manually shift up when racing every weekend for the past 3 years and nothing has happened, not a single noise or shifting problems. I usually rev up to 2800 max because it is quite hard on the transmission, just make sure to install some sort of aftermarket trans cooler because heat is not a good thing for the transmission.
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