i have a 93 prelude with a sh motor and the adapter plate to run a h23 trans, the car will vibrate between 25 and 50 mph only during acceleration and only at those speeds, i have replaced upper and lower ball joints outer tie rods and axles from autozone 3 times. i have had the wheels balanced and swapped them with a frinds and the vibration is still there.

the only other thing that i think it could be is the worn out shocks there pretty bouncy there old aftermarket kyb:
the car has front and rear camber kit, and innovative race motor mounts.

i switched back to my stock urethane filled motor mounts and the vibration was reduced a little, i'm really frustrated with the car and have put it up for sale but would rather fix the problem and keep it since i have put so much money into it.

please any help i will try anything to fix this.

 

Somethings out of balance! Where did you have the adapter plate manufactured?

Also, will the motor vibrate when the car is in neutral? You need to determine if its the motor vibrating or the tranny!. Isolation is the key !!

 

its not exactly an adpater PLATE, but thats the best way i could describe it, its actually welded to the intermediate shaft, and it was made by the mechanic that built my motor it was on his race car, there is no reall vibration when the car is nuetral, i can hardly tell it has the stiff mounts, i just figuired they put the motor in a bad postion.
so what could be vibrating in the tranny? the input shaft, also i have a resurfaced oem flywheel with probably 3000 miles of 400 horsepower mated to a six puck competetion clutch that chatters, i always thought the chatter was normal for the 6 pucks,

the vibration i get kind of feels like a steady clutch chatter, i can more so feel it in the front of the car then in the steering wheel.

 

vibration under acceleration often means you have an axle going out. Use raxles.com and not cheap autozone/NAPA axles.

 

i know but wouldnt the vibration be at all speeds not just 25-50, and are they really that sh***y that even after 3 axles they are all bad. i bought new ones not remans.

 

Does it do happen no matter what gear you're in, but always at those speeds? If it's speed related and not gear specific, I would assume you could isolate it down to axles, suspension, or wheels as you mentioned in your first post. I wouldn't think blown shocks would cause vibration or chatter like that...

 

yes, no matter what gear, and only at those speeds with acceleration, and it doesnt need a whole lot of pedal to feel it, but i soon as i let off and just cruise even at those speeds the vibration stops, i may just get some good DSS axles and see but id hate to waste 300 dollars. but if thats what it takes then ill try it.

 

well i ordered dss lelvle 0 axles and koni struts, so we'll see if that fixes it.

would the alignment cause the car to vibrate like this, i replaced all those components but never got it aligned, because i counted the threads and its worked on my other cars, i know, im gonna get one once i put in my struts, but could the alignemnt cause the vibrations?