TheSamba.com :: View topic - Midengine superbeetle build..Cadillac northstar..long travel

Mon Mar 02, 2009 6:10 pm

ok, that solvs the vibration but what about the twisting force? or the shock of the car as it travels terriegn? thats still quite a bit of force that will cause the mounts to get weak

Mon Mar 02, 2009 6:12 pm

well if it were enough to weaken the mounts (I personally don't believe that to be the case) it would do the same for solid or rubber mounts. That twisting force would have to go somewhere, even with rubber mounts.

Mon Mar 02, 2009 6:14 pm

the rubber alows for limited movemnt essentialy a shock obsorber. thats just my opinion

Mon Mar 02, 2009 6:16 pm

Thats very cool. thats thinking across the street from the box .. :shock:

I tryied talking my friend in to doing that and building a sick spare tire mount on the back off the car. where the motor normally is. :twisted: =D>

Mon Mar 02, 2009 6:16 pm

right, but that twist still has to be held by something. The rubber isn't going to hold the torque, just absorb vibrations. The chassis still feels the twisting force. Ever watch a high power drag car launch? Front half of the car twists one way, back half twists the other. That's the torque of the motor and the torque of the rear end fighting each other.

Mon Mar 02, 2009 6:19 pm

rubber is used as an isolator, so you don't transmit vibration, and or loosen other things.

Mon Mar 02, 2009 6:25 pm

i just belive that the solid engine mounts are going to become a weak link. it just looks like an awful lot of motor for that cradle and i can see fatuige possibly happening

Mon Mar 02, 2009 7:06 pm

A large major of v8 rails and race cars i have seen have been soild mount.

Mon Mar 02, 2009 7:23 pm

Pequin..thanks for the shifter link ill check it out!!
KB.....good idea on tire mount...im trying to keep the fenders and deck lids on ..i have some 3 inch wider fiberglass fenders (I might have to chop em up a little)..Im going for the stock look...lol..other than the v8 sittin in the back seat! ..and long travel..

As far as the solid mount topic..i thought about it alot..most the high dollar Ls1 sandcars or dragcars i have seen were solid mount...thats really the reason i decided to go solid mounts...
the last harley i built put out 120hp to rear tire had a solid mount motor the vibrations never bothered me ..( the women love it)..

just my opinion...i think the slack u get from rubber mounts actually makes it easier for the torque of the motor to twist and blow out mounts or break parts..as far as tweaking of the frame...im hoping tires and suspension will take care of that..im sure some flexing happens no matter what....So i think its a great topic!! These are just my thoughts:)
..I do plan on gusseting all that "motor craddle" tubing and supports in with the roll cage, shock towers and frame..
ill be workin on it tomarrow ill update some pics...

Mon Mar 02, 2009 7:27 pm

Those look like EMPI coilovers on the back of that Hog!! ;-)

Tue Mar 03, 2009 8:10 pm

started arms today, I bent and notched most the tubing..I need to move somethings around so i can finsih lower inside arm...

Tue Mar 03, 2009 10:18 pm

Its the vibrations that cause the cracks, but any race vehicle uses solid mounts. With vibes, they reach the high end of a life cycle quicker than other forms of motion. And heaven forbid you hit the ringing frequency of it.....Some people dom't like their teeth rattled out, but I don't like those kinds of people. You may want to ask around with the alum block & solid mounts. I've seen 2 LSx powered rails with soft mounts, but they were very high end and maybe the owners thought iot shook too much.

I think its a great choice for a motor, those things were ahead of their time, but the complexity led GM back to pushrod style motors. The ZR-1 1993 vette had 256 more moving parts in the engine than the future LS blocks.

Tue Mar 03, 2009 10:43 pm

this is rods buggy, i bought my adapter plate off him on ebay ..real nice guy..he sent me some pics, here is a pic of his mounts, he has been running his buggy for years with solid mounts....

Tue Mar 03, 2009 11:14 pm

i did some work on a buckshot car with a supercharged northstart, i guess it has been working for a few years solid mounted. it had much bigger problems to worry about though

Wed Mar 04, 2009 12:03 am

T4rail wrote: i did some work on a buckshot car with a supercharged northstart, i guess it has been working for a few years solid mounted. it had much bigger problems to worry about though

hey northstarbeetle you should get a blower for your northstar i dont think your gonna have enough hp with a N/A V8 on those big hillclimbs :lol: :lol: :lol: :lol:

Wed Mar 04, 2009 8:45 am

57...I like the way u think!

Wed Mar 04, 2009 9:58 am

northstarbeetle wrote:

You might want to rethink this a little. Having the tubes meet past the end of the bung will make the short tube want to crack right behind the bung. your main tubes should come all the way up to the main weld on the bung covering the rosette welds.

Thu Mar 05, 2009 8:51 am

bdkw....
I think you have made a great point....I just wished it had been a day sooner, I cant believe i didnt think about it.. :x ... I had already bent and notch most my tubing for both arms..I hate going backwards or wasting money.. but i think ive found a quick fix to the prob.. :evil:
I mounted the rear arms over the bung like u suggested....

I ran the trailing arm support all the way up on the inside bung..

Im also going to gusset the outside arms top and bottom all the way over the bung....

I think they should be stronger.. thanks for the advice!!!

Thu Mar 05, 2009 10:15 am

That should work.

Now for the other question thats a little late.... It looks like you axles are coming strait out of the tranny at ride height. They should be angled back a little so that when fully dropped out, your axle will be at 90* to the tranny for max travel and CV life.

Thu Mar 05, 2009 10:25 am

ya i actually thought about that a little and u cant tell from the pics but there is about 2* of sweep back ..not sure if it is going to be enough.. i knew where i wanted the motor and i didnt want the tires hanging off the rear too far..I can check it today to see were it is at at full drop...they sould be real close to 90*