My z finally hit the dyno l28et holset hx35r

[its_karl]

check the u joint on the driveline? when did the whine start?

[its_karl]

Yea but i have a crazy vibration at like 60 cant figure it out i just rebuild my rearend all new bearings etc so i can rule play out so its either driveshaft improper balance or wheel bearing but my wheels have no play so idk its soo annoying

I wouldnt rule out these if you just had the whine start, and just had this stuff rebuilt. rebuilt rear end, probably pinion shimmed wrong.

[Layzboy]

Idk its weird ubder partial acceleration it whines and stops whining until i floor it then it get a lil less worse any ideas? Could a misbalanced driveshaft cause this?

[72240z]

A drive shaft out of balance would do it at a certain rpm or condition in every gear not just 5th 

[captaingamez]

A drive shaft out of balance would do it at a certain rpm or condition in every gear not just 5th 

I would be looking into a transmission.

 

are you fs5w71 or borg warner?

[72240z]

Ya thats what I said last page, if its gear specific and even more specific on or off throttle only I would start at the transmission. 

[Layzboy]

Borg warner

[I'm BLUE]

You can hear the whine after i coast

 

when you were coasting in the video... were you in-or-out of gear while coasting ? (at the end)

 

My poly-urethane mustache bar diff bushings , and a rubber front diff mount maginfy's the noise from the rear-end into my s30's passenger cabin.

Do you have a hard-mounted front diff ?

Poly-urethane mounts in the transmission to ? (trying to get an idea mostly).

Differential strap mount in good condition ?

Diff mount in good condition ? (if not replaced by now or modified).

If the rest of the small stuff checks out... I'd double check your work on your rear diff first.. if it were me .. as they can be tricky now and then.

Could verify your diff specs as well at this point. ( I was thinking of the hardening ... but everyone of these diff's I've opened up look dang good ... )

Possibly swapping to a known good part if it's too much frustration , and everything else checks out .. give you a chance to inspect things (once everything has been tried/checked first of course.)

 

I screwed up on my first try on a diff rebuild years ago , and the pro-rebuilder chuckled at me lol... learned a lot then about what not to do as well as babysteps lol.

 

I hope it's not your trans.

Has 5th gear seen holy hell on the highway/freeway or boost ? lol ;)

Car get flogged quite a bit ? ( just getting an idea )

Correct and right amount of trans fluid in transmission ?

American transmission's are generally a bit noiser irregardless as we all know , but doesn't excuse an unknown noise.

 

Sorry I couldn't be of more help.

[Layzboy]

I have new rubber mustache bar rubber not poly

And i just bought the ron typer mount for the front diff mount with the poly mount

Transmission mount is stock rubber

So i have some news as of last night the vibration and noise seems to happen at about 45-75 then it gets less worse after 75 but the noise also goes away after 75 but anyway i messed around with my buddys gsxr750 did a pull from 65-150 (very surprised how fast it got up there and how fast i was going the bike couldnt pull away dont know why must be my 4;48 rear end gears

This thing is a highway rocket with barely 250 hp

[Layzboy]

[captaingamez]

Borg warner

Then you should upgrade to an FS5W71C from a 240sx, they are cheaper then BW and hold more power. Plus better gear availability, and more parts available. And on top of all that, You get access to the worlds cheapest short shifters.

[Layzboy]

I have a spare 240sx tranny but i dont think its thw tranny thats the problem it only made this noise and vibration since i had the custom driveshaft made so it has to be that

[captaingamez]

I wouldnt suspect the driveshaft, UNLESS, you suspect they may have not balanced it correctly? That is possible, but most shaft shops are pretty good about balancing it beyond where you will use it. You could always take it off and have them check the balance on it I think.

[I'm BLUE]

I have new rubber mustache bar rubber not poly

And i just bought the ron typer mount for the front diff mount with the poly mount

Transmission mount is stock rubber

So i have some news as of last night the vibration and noise seems to happen at about 45-75 then it gets less worse after 75 but the noise also goes away after 75 but anyway i messed around with my buddys gsxr750 did a pull from 65-150 (very surprised how fast it got up there and how fast i was going the bike couldnt pull away dont know why must be my 4;48 rear end gears

This thing is a highway rocket with barely 250 hp

 

Awesome.

Now... the RTz rear diff mount ... did you have that installed before or after the custom driveshaft ?

Isn't that going to transmit noise to the passenger cabin with a poly or rubber bushing ? (I'm not sure which you use)

If it does it can make good parts sound like they're going bad lol.

I mean the noise and vibration/force as to go somewhere right ? :)

 

My poly bushings in my yellow 240z mustache bar resonates quite a bit or noise , but I love it lol.

Mine can be slightly random on the pitch or the "drone" ocassionally ..... if I launch it gets worse until I let the car/suspension settle back down lol.

The noise I have also manifest's itself around 40+mph ... not consistent , but it's there (poly bushing's)

I have rubber mustache bar bushings on my blue 240z , and quite the difference it has.

 

When you speak of a vibration/noise are you talking about something that feels like it's wobbling/off center/shake the car bad enough ? or are you talking about a buzzing/loud/whirling type sound ?

 

Realizing those are aggravating questions as you've probably explained it before.

 

The reason I say this is the driveshafts I've felt vibrate or were severely out of balance I didn't dare drive up to the speeds you're talking about lol :) (not laughing at you just remembering some dumb stuff I did...)

I drove home my blue z with a driveshaft wobble of death ... worst one I've felt in a while ... years ago , and didn't feel like I was gonna make it .. like 6-miles from home lol.

 

This also reminds me of the 24,000lb street sweeper that had a bent drive-shaft ... from the job .... that was a fun day ... lol.

 

I have a spare 240sx tranny but i dont think its thw tranny thats the problem it only made this noise and vibration since i had the custom driveshaft made so it has to be that

 

The RTz rear diff mount ... did you have that installed before or after the custom driveshaft pertaining to the time of the noise/vibration ?

(opps asked that twice)

 

I've learned not all drive-shaft shops are equal , and the services sometimes aren't the same for the same price-ish.

 

oh yeah ... your s30 is def a LOT of fun at that amount of hp/torque....

[Layzboy]

Dont know why it posted a video of copa lol was suppose to be this video

idk if you can heat the whine more clearly and the vibration feels like a wheel out of balance but they are in perfect balance (reassured my self by test driving my wheels on a friends car after checking balance just to be sure

[I'm BLUE]

Car sounds great man :cool: , and I like the gauges.

haha coppa.

ahhhhhhhhh ok ...i see.

That ;erratic' whine sound towards the end(0:45+) I would bet is the RTz mount if it's poly (realize I keep preaching that)... sounds a lot like my yellow z with poly's .. :rofl:

 

The other vibration sounds more like it could be suspension/bushings (I realize you said you put all new bushings on though) , TCA/strut rod bushings ? (those crack and fall apart as you know... and if both are poly leaves no room for flex... I'm not sure if this has anything to do with anything in your case ...) , check for frame flex(weak/rotted areas) ... etc ... I'd look at your rack condition , and everything related as well as brakes... wheel bearings/play.

I'd check your tie-rod ends , steering rack bushings , steering coupler , and all of that... it feels like (to me) in these old s30's the typical problems that are suppose to show the typical symptoms do not , and instead manifest an array of several issues when trying to diagnose just one lol.

 

I guess if you truly feel the driveshaft shop missed the balance ... take it back and tell them whats going on :).

 

I remember torqueing my wheels just a bit off (without a torque wrench at the time since I broke it 10-mins earlier.. lol) , and man did that have vibration ! lol

Re-torqued them the next morning and all was well.

Of course if wheel spacers are bent/cheap/bad ... they'll wreak havoc as well as create a vibration... ask me how I know lol.

 

Sorry for being captain common sense this past little bit... , and I realize others have said the same :)

[Layzboy]

Yea idk it feels like its coming from right rear of the car and i tested space and wheels on another car no issues so idk what it is all my suspension components are brand new im running integra dc2 coilovers welded to the strut tube with techno toy tuning top hats

[Layzboy]

http://youtu.be/cy3Z3uwkN98

[Mannyvig]

A drive shaft out of balance would do it at a certain rpm or condition in every gear not just 5th

Not true, don't rule the ds out.

[72240z]

Not true? A drive shaft will only do it in 1 gear? Please feel free to elaborate and prove that.  

[Mannyvig]

Rpm doesn't affect a ds the way speed does. The speed a ds spins @ 3000 rpm in 2nd is completely different from its velocity @ 3000 rpm in 5th. The same idea of off balance wheels applies to the shaft. You may never notice a problem till that harmonic hits a certain speed, just as it may change if you keep going to an even higher speed. In short, engine rpm does not dictate driveshaft rpm.

[72240z]

No one said engine rpm dictated driveshaft rpm. Yes the DS spins at different rates of course but those rates overlap. If the sound is happening in 5th the only way it could ONLY happen in 5th is if hes topping the gear out, because if hes not then that ds rpm is repeated in 4th when at a higher speed.

A drive shaft balance issue usually will not only appear in one gear. Yes it may only be at a certain ds rpm but that rpm appears in more then one gear unless its the very bottom of 1st or end of 5th. I have diagnosed it on others cars many times... 

[Mannyvig]

No one is trying to discredit your diagnostic prowess. I just don't want a lesser diagnostician to read "a drive shaft out of balance will do it at a certain rpm in every gear", and believe that a junk u-joint will make the same vibration at "x" rpm in every gear. But what do I know.

[72240z]

I agree with you that nothing should be counted out until actually proven otherwise. Especially looking at a vid to try and diagnose... 

[datzenmike]

Safe to say that if the vibration is at the same RPMs (in any gear) then it's something forward of the driveshaft. If the vibration is at a certain speed (mph) then it's behind the transmission.