Just wondering since I think my Y is definitly hitting. I can feel something knocking around under the car when I accelerate.

BTW- how much clearance is needed between and exhaust part and the body with poly mounts. How much will the motor/exhaust move one way or the other? Sounds dumb, but I know that there is clearance, just not sure how much and have no idea how much the motor moves around with good mounts.

-James

 

Yeah, my headers are riding on my K member some and it is causing false knock, so it can happen. You need just enough clearance that it does not hit while under hard acceleration and going over bumps.

 

any idea on how much clearance that needs to be. i'd say its got about 1/4 inch. Maybe a little less.

 

I'd say a inch. i fought this problem for a long time. I finally got tired of the false knock and jacked the car up from all four corners. Make sure you support it from points that will not seperate the body...meaning have it set like its going down the road. I then crawled under it and loosend up all the bolts on the exhaust got a crow bar and a two by four and pryed exhaust where I wanted it....got about a inch clearence.....had another person maintain pressure prying while I tightened everthing back up.....let me stress the word TIGHTEN....and put it back on the road. I now only have a occasional bang when I power shift 2nd gear...other than that I never hear it anymore.

 

i have poly motor mounts on my LS1, and barely 1/2" clearance on the ypipe and frame right behind the collectors.

so you dont need much.

the engine barely moves 1/4" when reved up with the mounts.

 

I have probably a 1/4 inch clearance using the BMR k-member with poly mount. I do not have any issue hitting the k-member, but it did hit the tranny crossmember, so I notched that.

 

only a 1/4" cleareance with BMR k-member? what exhuast are you running

I have about a 1/8" cleareance with my JetLT and stock mounts and it just barely hits.

 

I am running Jet Hot LT's

 

i had heard that poly motor mounts would give you a tiny bit of clearance. my LT's are rattleing up under my floorboard as well. i'm installing the new motor mounts this weekend. i'll let you know if i still get some rattle.

i have the pacesetter LT's though.

 

did you finally get the car running I retuned and added all new ignition on my car and rewired the computer harness it burned thru and was causing knock on my car..when are you going to the track again I can meet up and maybe we can run them......

 

i did get her running. i am not getting much false knock, but i want 0. i took down a c6 on i20 a few days back, so i dont think im loosing much due to the timing. my only fear now is my 10 bolt with this power, and since im running a t56 with a spec clutch, its life isnt any easier.

 

I have a spec stage 3 also and i was wondering does it make like a grinding noise sometimes.....

 

im on my 2nd spec stage 3 in 10k miles, no racing
it always makes some sort of wierd noises

 

Lol my stupid hooker lts are touching the k-member on the pass side. Hell i had to hammer clearence the header a little just to make if fit. Guess i should have went with poly mounts.

 

Like a grrrrrr grinding sound and when your in reverse and easing off clutch....