Thread: Those who are Lowered.....WOT front vibration

A good friend of mine has a 97 GTP that is lowered and has a lot of mods done, it runs low 12s and we are shooting for high 11s this year with it. Anyways when he goes WOT the front end feels like it shakes and vibrates pretty bad. The car has had an alignment and does this with numorous sets of rims/tires though his daily summer rims are 20" with very low pro rubber so as you can imagine really amplifies the problem. He mentioned to me today something about reading that shortened upper motor mounts helping out with this issue and didnt know if anyone else has tried this. Then we got to looking at his upper mounts and he noticed the ones he found that were shortened look like stock ones and figured he could just shorten the stock ones but by how much? Thanks for those who can help out!

IF its lowering vibraitions he has a few options:

1) Drill new holes in the stock dogbones about 5/8" closer to the engine side of them.
2) Buy the shortened dogbones from WBS
3) Buy dogbones from a Pontiac Montana - Same ones as WBS
4) Buy offset upper poly mounts from ZZP
5) Buy my motor mount spacers - http://www.grandprixforums.net/f51/m...back-1107.html

Thanks for the info! The car also has cradle spacers because he has an aftermarket ram air hood. Because of the intercooler install I had to install the spacers as well as grind and mill a few area on the top of the blower so the hood would shut and not rub. He is going to try the shorter dogbones and see how that does.

The cradle spacers are hurting his cause in fighting the lowering vibration.

Yeah we figured that, just dont have an option since there is no clearance under the hood! I will post back after he tries shortened dogbones to see if it helps.

How low is low, like what springs is he running?

Sounds like the usual CV shafts are binding/bottoming out and not floating like they should under normal conditions.

The dog bones seem to be a good fix for many. I also created these billet front sway bar end link spacers that go between the bushing of the front sway bar and LCAs that were 1" shorter than stock:


Everyone who bought them for the reason of having the vibration all reported it either being completely gone, or severely minimized. All is still good to this day with them, not a single complaint ever.

~F~

Farns, do you have the hook up to make those and your sway bar end links again?

Not at this time. Maybe one or two at a time, the guy I am using now does not like production work. I have another guy i could use for stuff like this, but have not sat down and talked turkey with him yet about stuff like this. But he is an local automotive CNC guru and makes lots of stuff for cars as it is, so I don't think it will be a problem...hopefully not a bad price either.

The guy that was making these was doing them at home, and never liked to charge what a shop would charge cause hes logic was, the machine shops charge so much for so little done, to pay off their machines 100 times faster. His stuff was paid off the day it was delivered, and he just enjoys it, but no longer does it, which is a bummer.

~F~

I have a set of your old hourglass shaped ones. I don't even use the spacer anymore, just a couple washers.

Well if you ever have any of those made before I get my ride back together, let me know. I knew I should have picked up a set when you had them originally listed...

Those Hourglass shaped one, were of my very first design, and my personal favorites. I had these made because I kept cracking the stock plastic ones.


Then the second, and last batch (for now) had a new deign we came up with.


Remember the billet GMPP/Koni strut adjuster knobs I had made?

...then a vendor took on the sales of their own creation (knock off of mine which was a knock off of what was included when you bought the kit originally) the day I sold out. Thought that was quite convenient. LOL

~F~

That's how they roll....

I think I bought those hourglass ones off you like 6 years ago.

Gosh Farns, I want some of that stuff. I keep kicking myself for not buying a set when you were selling them.

for a cheaper fix pick up the enrgy suspension end links from AZ they come in different lengths you can cut the tube part shorter and what also helped for me is these home made trac -bars

Do you still make these?

bob, none of these guys are really active anymore. vinny does still sell spacers for the motor/trans mounts that will raise the motor/trans to realign the goofy angles from lowering.

to be honest i popped a new hole 3/4" back from the original in my dogbones and cut off the excess. this alleviated 90% of my vibration.

Thanks
I been using motor / trans spacers plus offset polys. Last motor swap I never put the spacers back. Thought it was over kill. Maybe I'll add them back

too short, brian. they're an inch shorter than ours.

Cutted some 1/4 steel flatbar and drilled holes, painted with corrostop and it made my spacers. Top and bottom, trans and engine, 1/2" raise. costed me a wooping 0$.
Lowered on SSC's, no vibration at all.