Hitmachine101

iTrader: (1)

hey guys/gals
got an 03 evo 8 with 155k on her

just had the tranny rebuilt with jacks transmissions and couldnt be happier with the results, shifts like butter and feels great

ive finally gotten the clutch disc broken in mileage wise and let her rip today and when i tagged 18psi i got an excessive wobble in the drive train

( note right before i yanked the tranny i was experiencing this as well -- thus why i yanked the tranny on top of the leaking it was doing 5th gear hum and general cruddy syncros )

up to this point smooth, shes been as glass at any acceleration or crusing speed except full boost

so 5psi great 10psi no problem even 12-15 still great

but when she hits the full boost mark, theres that wobble mostly in 2nd and 3rd

talked to a family friend hes suggesting a motor mount/ tranny mount might be the cause

my first thought was a u joint or the carrier barring for the driveshaft

any insight on this one? anyone ran into this problem?

oh btw the tcase was built by shep 50k ago so were all set there

Thanks for the help ahead of time

Biggiesacks

I would check/replace spark plugs and do a boost leak test to start with.

Bhsj13

^^ What he said along with all the mounts. let us know what you find.

Hitmachine101

iTrader: (1)

plugs are gaped right and are 2k old -- actually had the car cutting out on me when i first put it on the road and the plugs cured it

ill take a look at the mounts when i get a free chance
had them all out with the exception of the passenger/timing belt area mount and the others looked fine

the recommendation my friend had was to pull the ebrake and have someone watch the engine bay as i engaged first basically loading the car to see how much everything moved -- he figured with as much torque and hsp these cars produce something isnt lined up right and is causing the issue

Bhsj13

Hmmmm... what about at high speed cruising off boost?

Hitmachine101

iTrader: (1)

havent been much above 70 since the change out -- on my way to work in the morning ill take her up above 80 and see how things go -- my gut says still no issues and smooth but its worth a shot ill report back then

Biggiesacks

the fact that its only happening at a high boost level, and not at a certain speed or gear, really makes me suspect it has to do with the engine. A boost leak could be causing it to run really rich, perhaps one of your coils is going bad. Hard to say really but thats what my gut is tellin me.

Hitmachine101

iTrader: (1)

was at 80 this morning a couple times and nice and smooth
boost leak test is next for sure

in general the car has been shaking more at idle
figured it was the old gas running through but im beginning to think ive got a motor mount thats at the end of its life

interesting enough i was boosting in 3rd and going around a small long corner and she was nice and smooth - the instant i got straight again wobble returned

im really thinking somethings shifting on me in this engine bay

which engine mounts have you guys replaced first with your repairs and general
maintenance of these cars?

oh and the engine dampener, did some adjustment to that but no results, that is original to the car as well -- that need to be changed or should i just change that mount and call it a day on that side of the motor ?

Hitmachine101

iTrader: (1)

update
still havent gotten a chance to get over to my barn to do a boost leak test -- wobble still present in wot pulls

i took a look at the trans mount and motor mount on the passenger side and did the old crow bar trick -- seems to be a lot of movement in the passenger side mount while little to none in the drivers side tranny mount -- visually inspected the pass mount and theres no tearing however the rubber seams tired if that makes any sense i can move it around fairly easily

thinking going poly is over kill for my driving -- very little track time so either oem or sturdy aftermarket -- any thoughts or recommendations?

Bhsj13

I would get another OEM one and change the front one. I have the BLOX front roller stopper mount and it works well.

Hitmachine101

iTrader: (1)

had an alignment done as well today ( i work at a tire shop ) didnt help the wobble still there but kinda figured it would be, better fuel economy and less tire wear never hurt anyone however so money well spent

I ordered a oem mount from mitsu -- itll be here on monday the latest hopefully saturday -- ordered the passenger front mount

tomorrow I will boost leak test the system and cure those leaks and issues --
guess im playing the waiting game for now

all the mounts are original so i should probably replace all of them
main tranny mount the next one i should do or do you guys suggest one of the others first given my symptoms?

Hitmachine101

iTrader: (1)

front mount then would be next?

Bhsj13

for daily driving i would only do the front one with the other 2 oem. the other two will allow you to feel more of the vibration. I would say the front one and your engine damper would be fine. I do however, suggest changing out your stock underhood shifter bushings to a solid one. makes the shifting feel better.

Hitmachine101

iTrader: (1)

ok more updates:
went and got a coil pack and swapped it in and out with the two and took a couple test drives and still wobble

all plugs are gapped correctly and and in great shape

boost leak test did show some pipes in need of a turn or two of the clamps
after doing that the wobble lessened ( in my mind maybe -- thus why i went to the coil pack spark route )

put 4 basically new tires on today as well -- had them on a parts car and i needed a reason to swap my current tires off because they were low on tread anyways

now im safe with thick tread for the rochester Winter but the wobble did not go away

soooo more or less im look at these engine mounts or possibly carrier bearings on the drive shaft even thought they look great

first mount comes in saturday or monday at the latest so looks like ill be taking it easy until then

Biggiesacks

would you be able to upload a vid of the wobble happening?