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-   -   help!! jerky launch.. rpm drops (http://www.the370z.com/engine-drivetrain/100305-help-jerky-launch-rpm-drops.html)

binoy29 01-27-2015 11:47 PM

help!! jerky launch.. rpm drops
 
When I engage 1st, I hold the throttle so it sits at about 2k RPM, and then slowly release the clutch. Then when the car starts moving, I HOLD the clutch in that spot for about a second or 2 then slowly release the rest of the way. I've found this is the only way I can get a smooth launch. Is this a bad way to do it? I couldn't really find any info on people pausing on the clutch for a sec while engaging 1st.

i launch close to 2k rpm, but everytime im releasing the clutch on 1st gear my rpm drops causing my laucnh to jerk. does this happen to u all? rpm drops causing to jerk.

ive driven a lot of manuals but this is my 1st Z manual. i have 09 sports package 45k miles

madwi 01-28-2015 12:54 AM

Are you trying to launch at a track or do you mean just driving normally and starting from say a stop light?

Breadz 01-28-2015 02:11 AM

1st and 2nd are very rough/jolty if you let go of the clutch 2 fast
unlike any other manual i have ever driven

and if your racing/trying to launch fast do you have VDC turned on?

juld0zer 01-28-2015 02:27 AM

i think you are riding the clutch for too long. this car seems to have a very narrow friction point, which is exacerbated by the strong clutch 'helper' spring. it makes the pedal feel like an on/off switch so once you have friction, just apply more gas and continue releasing the clutch pedal.

you dont need to take off under normal driving at 2000rpm. i usually take off between 1200-1500rpn but u do have a few hardwaremods and a modified throttle table.

i just took my helper spring out and omg it feels so much better now!!

binoy29 01-28-2015 08:21 AM

why does the rpm drop when im close to clutch grab point? this causes me to jerk. and i dont race.

2011 Nismo#91 01-28-2015 09:03 AM

Starting in first gear:
Very slowly, begin to lift your left foot off the clutch as you press down on the gas pedal with your right foot. This is called "slipping the clutch," and it can take some practice. Ideally, this will be a gradual, smooth movement, and it will result in the car gently rolling forward. In reality, you can expect to stall the car a few times or lurch forward suddenly as you learn this step. All it takes is practice. If the car stalls, return to "Start the Vehicle" to restart it.
Remove your left foot from the clutch and continue driving until the tachometer indicates that it's time to shift to second gear.


Your rpm drops because your are putting a load (3,300lbs) on the engine as compared to idle where there is almost no load on the engine. As your clutch engages more you'll need to give more gas to keep the rpms up and keep from stalling.

SouthArk370Z 01-28-2015 09:15 AM

If the brake lights are on, the ECM limits power/RPM. Is that what you are seeing? If so, you can clip the feedback wire from the brake lights to the ECM.

2011 Nismo#91 01-28-2015 09:30 AM

I don't think he'd doing heel toe.

tturbo370z 01-28-2015 09:33 AM

Welcome to owning a Z :rock: i have had lots of manual cars and this one by far takes the most finesse. They are clunky and noisey but the more u drive it the better u get at it and used to to. Following the advice given above will help. I mostly **** around the same mentioned 1200-1500 and Its fine for me. If I'm slowly creepy up the drive way I got he garage is around 1500 or a pinch higher or it clanks around pretty bad. I also have a os Giken clutch which is a lot less forgiving as it's either on/off. Good luck OP

2011 Nismo#91 01-28-2015 10:44 AM

I think I stalled mine about 5-10 times just on the first afternoon I had it, and I have been driving manuals for over 15 years.

Skyscraper 01-28-2015 03:09 PM

They are super touchy, just a pretty poorly designed component by Nissan. Either swap out the Clutch helper spring for a lighter one or get an aftermarket pedal assembly like the RJM performance one. Mine should be getting made this week and shipped out soon, can't wait to feel it when it's installed. All that shudder and herky jerky is annoying with the stock system.

Breadz 01-28-2015 03:23 PM

Quote:

Originally Posted by Skyscraper (Post 3095157)
They are super touchy, just a pretty poorly designed component by Nissan. Either swap out the Clutch helper spring for a lighter one or get an aftermarket pedal assembly like the RJM performance one. Mine should be getting made this week and shipped out soon, can't wait to feel it when it's installed. All that shudder and herky jerky is annoying with the stock system.

Ya im like 3/15 on the list for the rjm. HYPE

nis350 01-28-2015 05:44 PM

The clutch on the Z is on and off, there is little in between. So you just have to practice to 'slip the clutch' a bit. It can get scary if you have to start on a steep incline. Make sure you have plenty of room in the front and back of your car to avoid accident.

Quote:

Originally Posted by 2011 Nismo#91 (Post 3094817)
Starting in first gear:
[I]Very slowly, begin to lift your left foot off the clutch as you press down on the gas pedal with your right foot. This is called "slipping the clutch," and it can take some practice. Ideally, this will be a gradual, smooth movement, and it will result in the car gently rolling forward..


juld0zer 01-28-2015 08:33 PM

Quote:

Originally Posted by SouthArk370Z (Post 3094825)
If the brake lights are on, the ECM limits power/RPM. Is that what you are seeing? If so, you can clip the feedback wire from the brake lights to the ECM.

yep, there could be an issue with OP's car. but if he is taking off the way i picture it (hold revs at 2000rpm and clutch pedal all the way down, then gradually release the clutch pedal), the car should take off pretty briskly albeit with the cabin reeking of clutch smoke

Powerwiz 01-28-2015 09:41 PM

Most likely your introduction to the Z clutch. Its good after 2nd imo. I have a 2015 model and when I first drove it I thought I had forgotten how to drive a standard. There is a aftermarket replacement that some on here rave about. I shall be installing it this spring.


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