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-   -   Trying to run NO subframe bushings, lowering the engine back down to compensate? (https://www.lateral-g.net/forums/showthread.php?t=26805)

BritishGreen68 05-12-2010 07:44 PM

Trying to run NO subframe bushings, lowering the engine back down to compensate?
 
So here's what im doing lol.. Im trying to get my camaro as low as possible. I removed the subframe bushings and bolted it directly to the body to try and keep the sub from hanging down so far under the car, as well as lower the car a little more. Im running a T56 with sbc, and as we all know the T56 barely fits as it is. So, my plan is to notch the cross-member for the oil pan, and modify the frame/motor mount stands to lower the engine back down to where it normally is in relation to the body, so the tranny will clear the tunnel. Anyone else tried this? Tips tricks comments?? I don't want to cut up my tunnel...!
Issues Im seeing are headers, of which i will just run shorty's, steering column is flaming river so the u joint deal is already taken care of, and clutch linkage is easy.. should I bother doing all this?:faint:

coolwelder62 05-12-2010 07:49 PM

Sounds like your oil pan & trans now might hang below the lowest parts of the frame.Any hard driving and you might have a problem grinding some drive train parts on the pavment.Good luck.

ProdigyCustoms 05-12-2010 08:12 PM

Done it many times. Raise the transmission tunnel. Do not lower the oil pan lower then the crossmember

elitecustombody 05-12-2010 08:48 PM

Frank, how is the noise,rattles,vibration? I'm thinking of doing that on my 69 bird or should I just channel it?:unibrow:

ProdigyCustoms 05-12-2010 08:58 PM

No different then using solid bushings or welded in frame connectors.

I like to build all my stuff frame as rigid to the body as possible and let the suspension do the work

Vegas69 05-12-2010 09:09 PM

IMO, you need to cut the tunnel to get proper u joint working angles. When I say proper, I mean 1-2 degrees of working angle front and back. As low as we run these cars moving the engine down a little isn't going to gain the clearance needed in the trans tunnel to get a driveline angle that works well. With the high driveshaft speeds we are all after(5th gear at 100mph)smaller angles become critical for silky smooth operation. I wish I would've raised my tunnel. Otherwise, it's simply a compromise on u joint angles and vibrations of some kind will exist as your driveshaft speed increases. I'm still messing with mine to this day. Cutting my tunnel may still happen down the road.

BritishGreen68 05-12-2010 09:31 PM

Quote:

Originally Posted by Vegas69 (Post 287119)
IMO, you need to cut the tunnel to get proper u joint working angles. When I say proper, I mean 1-2 degrees of working angle front and back. As low as we run these cars moving the engine down a little isn't going to gain the clearance needed in the trans tunnel to get a driveline angle that works well. With the high driveshaft speeds we are all after(5th gear at 100mph)smaller angles become critical for silky smooth operation. I wish I would've raised my tunnel. Otherwise, it's simply a compromise on u joint angles and vibrations of some kind will exist as your driveshaft speed increases. I'm still messing with mine to this day. Cutting my tunnel may still happen down the road.

Ok, well sounds like I need to just raise the tunnel, that's good advise on the motor hanging lower the the crossmember as well. I actually had a diveshaft angle problem before all this, and always had a vibration on decel so i guess plan A is to get that squared away this time.. for some reason i always cringe when I cut up old sheetmetal, but its not like im ever going to put it back to 100% stock so what the heck..
Hey Frank, those Billet Specialties wheels I got through you are beautiful, I need a g link now. You got one laying around???:unibrow: :D

Vegas69 05-12-2010 09:43 PM

The problem is, when you lower these babies the driveshaft angle rises towards the rear of the car if you try to run equal and opposite angles with factory driveline angles(3-4degrees) the working angles reach 6.5-7 degrees or more. They can be equal and opposite but it will still cause a high speed vibration of some sort. I'd shoot for getting your driveshaft pointing down towards the rear of the car around 1 degree with a driveline and pinion angle of approx 2 degrees(equal but opposite. That will give you a working angle of only 1 degree and will run silky smooth until the car runs into the aerodynamic wall. (These are just estimates) Of course your rear suspension will effect if you need to put any preload in the pinion. With anything but leaf springs, I'd prefer smooth driving and less than ideal angle under WOT. Solid motor and body mounts will only compound any driveline angle issues and harmonic problems. I've done a little research and chasing my tail, can you tell. :unibrow:

ProdigyCustoms 05-12-2010 09:45 PM

Quote:

Originally Posted by BritishGreen68 (Post 287124)
Hey Frank, those Billet Specialties wheels I got through you are beautiful, I need a g link now. You got one laying around???:unibrow: :D

Ready when you are. Call me if you need any help.

Vince@Meanstreets 05-12-2010 10:41 PM

We do it on all of our builds to keep the geometry sane. As good as it feels you'll never notice the NVH.

Just a warning, it does take a bunch of work on some cars.

Radiator and shroud clearance. Steering shaft angle. As Frank mentioned, trans tunnel mods. Shifter location in console. Exhaust to floor clearance. Engine to hood clearance. Tire to wheel well clearance.

Oil pan goes up with the frame but watch your pan use and great points on driveline angle.

I like to use 5/8" dowels at the body/frame alignment holes and sleeves to keep thrframe in alignment after its gets squared.


Good luck with it, its a great mod.

Vince


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