Cure for high speed nervousness?

SPDKING · 04-19-2019, 09:26 PM

What are people doing to cure the high speed nervousness of the Z34?I was doing about 65 at highway speed and someone suddenly were hard on their brakes ahead of me to avoid a fridge that fell off of a pickup truck.

When I went hard on the brakes I quickly reacted because it looked like I wasn't going to stop in time to avoid a rear end collision when pressing the brakes and changed lanes because I didn't see a car next to me just 20 seconds earlier. I felt a lot of vibrating in the steering wheel and in the car so I assume I overloaded the front tires so much that I was losing grip, the car also seem to dart uncontrollably for a split second and regained composer.

I figured with the tires and new shocks and sway bars (I know they only come into play in hard cornering), this might cure the Z34 nervousness but it felt the same as it did when it went over road imperfections at high speed.

Has anyone tamed this for the street and track? It scares the crap out of me and my 350Z never did this, it always felt flat and stable at high speeds even in stock form. Do I need to soften my front struts? I'm running full soft in the rear and full stiff in the front with brand new tires with only 100 miles on them. I know I need coilovers in the future but who's solved this nervousness at high speed issue? If it's doing this in emergency situations on the street, I feel like it's going to do this at Willow Springs if I'm hard on the brakes and then trying to change direction quickly after getting off of them. Will making the front full soft fix this?

OptionZero · 04-19-2019, 09:33 PM

sounds like you need an alignment

SPDKING · 04-19-2019, 09:35 PM

Quote:

Originally Posted by OptionZero

sounds like you need an alignment

I had an alignment after I got the brand new tires. The sway bars and shock+struts came after

Trips · 04-19-2019, 10:33 PM

Sounds like your rotors are warped.

You shouldn't have any vibrations while braking.

You may also have a brake caliper slow to react and can also lead to pulling to one side IF your alignment is good.

Spooler · 04-19-2019, 11:40 PM

If you darted when you stomped on the brakes it was more than likely due to brake pad buildup on the rotors. This is also why you had some brake pedal shudder. That is why I don't care for the stock brake pads. They are bad about brake pad build up on the rotors. I would suggest you re-bed the pads in and see how it goes. It will clear of the brake pad deposits off the rotors. Your braking should come back to normal.

BGTV8 · 04-20-2019, 01:30 AM

Did you trigger the ABS ?? as well as Stability/Yaw Control when switching lanes ........

Can be freaky if you are not expecting it

I have no problems with the Z34 platform on the track.

SPDKING · 04-20-2019, 10:57 AM

Quote:

Originally Posted by BGTV8

Did you trigger the ABS ?? as well as Stability/Yaw Control when switching lanes ........

Can be freaky if you are not expecting it

I have no problems with the Z34 platform on the track.

The ABS light never came on, I didn't jam on them that hard to trigger it but when I switched lanes quickly I wasn't on them at all and it almost made a noise like those Front wheel drive cars that understeer. I have about 23k miles and had a check up on the suspension, brakes and any chassis bracing and only found that the stock front passenger strut was leaking and nothing else. Everything was basically all stock. Would the stock brake pads be that bad to cause this? Or the rotors?

redondoaveb · 04-20-2019, 11:36 AM

Quote:

Originally Posted by SPDKING

The ABS light never came on, I didn't jam on them that hard to trigger it but when I switched lanes quickly I wasn't on them at all and it almost made a noise like those Front wheel drive cars that understeer. I have about 23k miles and had a check up on the suspension, brakes and any chassis bracing and only found that the stock front passenger strut was leaking and nothing else. Everything was basically all stock. Would the stock brake pads be that bad to cause this? Or the rotors?

Did you talk to Alex about the issue when you took it in to him?

OptionZero · 04-20-2019, 12:55 PM

Quote:

Originally Posted by SPDKING

I had an alignment after I got the brand new tires. The sway bars and shock+struts came after

You got an alignment BEFORE you installed shocks/springs that lowered the car?

You realize those parts affect your alignment?

SPDKING · 04-20-2019, 01:11 PM

Quote:

Originally Posted by redondoaveb

Did you talk to Alex about the issue when you took it in to him?

I didn't, I've had this before if I was cornering too hard with some crappy Goodyear's that were on it when I got the car. No braking involved at all in that situation and that went away after I switched tires. I didn't have this until I braked hard yesterday and then switched lanes.

SPDKING · 04-20-2019, 01:12 PM

Quote:

Originally Posted by OptionZero

You got an alignment BEFORE you installed shocks/springs that lowered the car?

You realize those parts affect your alignment?

My car is stock height, I just have sport dampers and shocks with stock springs

Rusty · 04-20-2019, 07:16 PM

Quote:

Originally Posted by SPDKING

My car is stock height, I just have sport dampers and shocks with stock springs

If you have sport dampers. Are they oem? How do you adjust them?

SPDKING · 04-20-2019, 10:06 PM

Quote:

Originally Posted by Rusty

If you have sport dampers. Are they oem? How do you adjust them?

I have Koni Yellows that are adjustable with stock springs. I can adjust how how stiff or how soft the front or rear can be similar to coilovers that adjust dampening but I can't raise or lower my ride height.

Rusty · 04-20-2019, 10:21 PM

Quote:

Originally Posted by SPDKING

I have Koni Yellows that are adjustable with stock springs. I can adjust how how stiff or how soft the front or rear can be similar to coilovers that adjust dampening but I can't raise or lower my ride height.

I know about Koni's. But the way you worded it sounded kind of confusing. You said the way you have the dampers adjusted, then said you have the sport dampers. Meaning you have the stock sport dampers.

Rusty · 04-20-2019, 10:29 PM

since you changed from oem to Koni's after you had an alignment. I would get it aligned again. The Koni's will lower the front by at least a 1/4". The lower spring perch is lower on the Koni's. Also the toe setting is most likely off. If the setting is zero to toe out. The car becomes less stable.

04-19-2019, 09:26 PM	#1 (permalink)
SPDKING Base Member Join Date: Dec 2016 Location: Los Angeles Posts: 207 Drives: 14' Nissan 370Z SP Rep Power: 1999	Cure for high speed nervousness? What are people doing to cure the high speed nervousness of the Z34?I was doing about 65 at highway speed and someone suddenly were hard on their brakes ahead of me to avoid a fridge that fell off of a pickup truck. When I went hard on the brakes I quickly reacted because it looked like I wasn't going to stop in time to avoid a rear end collision when pressing the brakes and changed lanes because I didn't see a car next to me just 20 seconds earlier. I felt a lot of vibrating in the steering wheel and in the car so I assume I overloaded the front tires so much that I was losing grip, the car also seem to dart uncontrollably for a split second and regained composer. I figured with the tires and new shocks and sway bars (I know they only come into play in hard cornering), this might cure the Z34 nervousness but it felt the same as it did when it went over road imperfections at high speed. Has anyone tamed this for the street and track? It scares the crap out of me and my 350Z never did this, it always felt flat and stable at high speeds even in stock form. Do I need to soften my front struts? I'm running full soft in the rear and full stiff in the front with brand new tires with only 100 miles on them. I know I need coilovers in the future but who's solved this nervousness at high speed issue? If it's doing this in emergency situations on the street, I feel like it's going to do this at Willow Springs if I'm hard on the brakes and then trying to change direction quickly after getting off of them. Will making the front full soft fix this? __________________ Stillen front and rear sway bars/Continental Extreme Tires/Annex Suspension Coilovers/Z1 Oil Cooler/Borla Catback Exhaust/K&N Drop in filters/SPL

04-19-2019, 09:33 PM	#2 (permalink)
OptionZero A True Z Fanatic Join Date: Apr 2011 Location: Sacramento Posts: 3,260 Drives: 15 370Z Nismo 6MT Rep Power: 214101	sounds like you need an alignment Brendan and wanker like this. __________________ OptionZero Build Thread

04-19-2019, 10:33 PM	#4 (permalink)
Trips Administrator Join Date: May 2009 Location: Disneyland, Ca Posts: 8,732 Drives: 🔰 Rep Power: 10	Sounds like your rotors are warped. You shouldn't have any vibrations while braking. You may also have a brake caliper slow to react and can also lead to pulling to one side IF your alignment is good. __________________

04-20-2019, 01:30 AM	#6 (permalink)
BGTV8 A True Z Fanatic Join Date: Dec 2009 Location: 03350 Australia Posts: 1,515 Drives: 09 Nissan 370Z M6 Rep Power: 39974	Did you trigger the ABS ?? as well as Stability/Yaw Control when switching lanes ........ Can be freaky if you are not expecting it I have no problems with the Z34 platform on the track. Rusty likes this.

04-20-2019, 10:29 PM	#15 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 69 Posts: 35,422 Drives: 2011 Nismo GM 6M Rep Power: 2684438	since you changed from oem to Koni's after you had an alignment. I would get it aligned again. The Koni's will lower the front by at least a 1/4". The lower spring perch is lower on the Koni's. Also the toe setting is most likely off. If the setting is zero to toe out. The car becomes less stable. dts3 likes this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html

04-19-2019, 11:40 PM	#5 (permalink)
Spooler A True Z Fanatic Join Date: Jun 2014 Location: Ga Posts: 14,041 Drives: 2013 Nismo 370z Rep Power: 2684393	If you darted when you stomped on the brakes it was more than likely due to brake pad buildup on the rotors. This is also why you had some brake pedal shudder. That is why I don't care for the stock brake pads. They are bad about brake pad build up on the rotors. I would suggest you re-bed the pads in and see how it goes. It will clear of the brake pad deposits off the rotors. Your braking should come back to normal.

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