Who knows about drivelines? Common problem

[Julioluko]

So I've been working on this car way too long, but one thing that bothers me is the vibration you get at low rpms and a high gear. I love shifting,just going through the gears makes me happy and it gets me better gas mileage, and If you step on the gas in 5th gear going slow around 35mph, you get this slow "woomp"....."woomp"...."woomp" that follows the road speed and gets progressively faster and eventually goes away. Does anyone know what I'm talking about here, and is there a fix???

 

[Afroclipse]

Do you have balance shaft eliminated.

 

[Julioluko]

nope still there, 92' 6 bolt (stock) in a 96GSX

 

[toojung2die]

If you step on the gas in 5th gear going slow around 35mph, you get this slow "woomp"....."woomp"...."woomp" that follows the road speed and gets progressively faster and eventually goes away.

I have an A/T so I'm far from an expert but when I have driven manual transmission cars and I tried to accelerate from 35mph in fifth gear I always got an embarrassing vibration that was an immediate clue to my passengers that I wasn't very good at shifting and should be in a different gear.

 

[busted_4g63]

Just sounds like you bogging down in a high gear at low rpms. And the fix, shift to a lower gear and then hit the gas. Does you car get the "wommp woomp sound" maybe in 3rd gear going 35mph at low rpms?

 

[BoostedTalonTS]

U-Joints & hanger bearings man... Been there & done that already

 

[DSM1G90]

going 35mph in 5th??...REALLY! Fill the motor up with carbon, will yas?

 

[Julioluko]

I think this is a common occurrence in cars, when you step on it in high gear and lower speeds. It sounds like maybe the tires might be out of balance, or maybe its the transmission shifting in the mounts, and trust me i do blow out the carbon occasionally.

 

[Julioluko]

This is not a huge problem like a thud thud thud, someone try this out in you car and you'll notice it. My dads front wheel drive MX-6 did the same thing, not to says its not the u-joints but its would seems its something else.

 

[kanderson]

BOGGING! Just downshift and it will go away.

I do know what you mean and it is not in the driveline. Almost every car does it, the only ones that haven't in my experience are the ones with LOTS of low end torque, something our cars do without.

 

[Julioluko]

Hey i just drove my friends 00 Passat (2.4L V6 manual) and it was completely smooth, i brought it down to 200rpm's in 5th!!! and speed up with no vibrations whatsoever, I gotta admit i was kind of impressed. Now it is a V6, but its not that big, I wish i had and under car cam.

 

[kanderson]

OK, you got me there. I don't really know what it is, but I think that it is just harmonic imbalances in some engines at certain rpms. A lot of engine's rev limits are determined this way - if there is a bad imbalance after 6000 or so rpms, than they just set the limit before this. However, it is beyond me why some engines have these symptoms and others do not.

 

[Julioluko]

True story I know these engines are decently balanced, but having 6 "pushes" per revolution VS 4 "pushes" per revolution would be smoother. Any other input?