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280zx wheel hop at the strip.


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#1 redzedturbo

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Posted 07 September 2016 - 03:49 PM

Hey guys it been a while huh. Well me and xnke went to the drag strip last Saturday and the first pass out i was joking and told him i was going to cut the tree down on him. My reaction time was 0.422 and i hit it hard out of the hole. The car shook so bad my sun visors came down and it threw my keys out of the ignition into my lap. I found out about the keys when i got to the staging lanes and went to shut the car off and the keys were gone! They were found under my crotch in the seat. Any ways some back story for you guys that dont know my car. L28et big cam Turbonetics To4e 50 with stage 3 turbine wheel .63 turbine housing. Im also running megasquirt ms1 v3 at 16 psi that night. The last time we went i had the same setup but still had the stock diff (open) and it launched hard with little to no hop just some tire slip. I have been running this obx diff for over a year no issues until we hit the track. I checked my axles and driveshaft today at work everything good and tight. After all the shaking thought it was worth looking because it was the most violent tire shake i have ever experienced in any car. Do any of you guys have this problem? Im going to switch all my rear bushings to poly next week to see if it helps when we go back on the 29th. All i could manage was a 13.4 at 104 and last time with open diff same boost ran 13.1 at 108 but without wheel hop giving me shaken baby syndrome. Thoughts    


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#2 FricFrac

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Posted 07 September 2016 - 05:31 PM

The ZX usually squats pretty hard when you launch. When it squats it's going to toe in.

I'd start with checking all your bushings. Never had wheel hop in a 280ZX...

1969 Datsun 510 2dr Z22ET, 1972 Datsun 510 2dr L28, 1972 Datsun 240Z, 1981 Datsun 280ZX, 1981 Datsun 280ZXT 3.1l stroker, 1983 Datsun 280ZX, 1983 Datsun 280ZXT, 1993 300ZX Convertible, 2009 Nissan 370Z


#3 aarang

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Posted 08 September 2016 - 08:08 AM

Had the same problem with my ZX at the track. First time it happened it felt as though the car was going to split in two. Had to slip the clutch alot to calm the hopping down, but lowering my tire pressures pretty much stopped it in my car. I have poly bushings as well. Interesting, though is my car went 13.2 at 108 with the stock turbo and ECU


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#4 SHADY280

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Posted 09 September 2016 - 04:11 PM

I have all new bushings in mine and the Mercedes old school spring swap. I shook so bad one day with my open diff it threw off number 6 spark plug wire! It felt like I really broke something.
Posted ImageCanadian zeds go faster.......colder air

#5 redzedturbo

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Posted 09 September 2016 - 04:20 PM

well i fixed some problems last night. My datalogs showed my boost at 17 when i went wot but at 4500 was dropping to like 10 till rev limit. So i removed my ace hardware boost controller to find i could blow through it meaning the ball and seat were not sealing right. Anyway new ebay hallman copy replacement boost controller and now faster boost onset and holds + or - 15 kpa what i set it at. Setting now it 220 kpa so around 17.5 and it runs so much better. I forgot how fast this thing was!! This week i am removing the rear sub frame at work to install cut down z31 poly bushing and poly control arm bushings in hopes of eliminating the hop! Will try to take pics and post.


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#6 redzedturbo

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Posted 09 September 2016 - 04:22 PM

I need to get some higher spring rate coils for the rear im running the tokico kit. The rears are i think 200 lbs and on a launch i can bottom the strut out. Thinking of going to s13 coilovers at tax time.


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#7 JMortensen

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Posted 09 September 2016 - 04:55 PM

I think stiffer springs are going to be the ticket.

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#8 redzedturbo

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Posted 18 September 2016 - 03:17 PM

Well i got the z31 bushings cut down and installed which was the easy part the control arm bushings were a lot more work. I used the torch a lot and a big hammer and various chisels and punches. The vibration after the bushing install has been annoying but i think i can get used to it. I am going to check my drive shaft angle tomorrow using the angle gauge i got at ace hardware today for $10. The rear of the car is much stiffer and much more stable. I think my wheel hop will be all but cured when we go back to the strip on the 29th. Ohh a side note i had to install the rear assembly diff mount first then shift the whole thing backwards like an inch to get on the sub frame studs. This centered my rear wheels in the wheel arches finally after years of thinking to myself that the rear wheels sit so far forward in the arch. I highly recommend this to any zx owner the difference is night and day.   


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#9 G-Tech

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Posted 13 October 2016 - 08:37 AM

I have a 83zx with a ls1 in it with 400whp. I was having the same problem with the wheel hop which was causing me to snap stub axles. a guy explained to me as the car squats it toes in causing it to lose traction, as the suspension unloads it gets grip again causing it to squat and repeat the vicious cycle. I also feel it was because I was bottoming out the struts which cause the rear to bounce back up...I have poly bushings, quife rear diff, whithead performance 300m stub axles (which took 8 months to get), with 300zxt half shafts and I have had custom springs made a couple times and now im up to 420lb springs. the car still rides pretty good and it only squats a lil bit. it runs consistent 11.9@116mph with 1.75 60FT times. the car hooks so good with 235 wide tires. I hope this helps. I am curious exactly what you did to move the rear subframe back. I have been wanting to do that for years.

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#10 G-Tech

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Posted 13 October 2016 - 08:41 AM

so bottom line is the stiffer springs didn't allow it to squat as much. I have not had wheel hop issues since I did the stiffer springs.



#11 NewZed

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Posted 13 October 2016 - 09:48 AM

 a guy explained to me as the car squats it toes in causing it to lose traction, as the suspension unloads it gets grip again causing it to squat and repeat the vicious cycle

Could you increase toe (more toe-out) at the track so that you get maximum traction at full squat?  Go from toe-out to neutral on launch.  Just a thought.  Stiffer springs reduce squat which would reduce weight transfer, and traction, I'd guess.



#12 redzedturbo

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Posted 13 October 2016 - 10:23 AM

Installing the 300zx poly bushings moved the rear sub frame back. My rubber bushings were shot but i dont know what thickness to tell you to cut the bushings i just eye baled it and now i have some driveshaft vibe.


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