PDA

View Full Version : Suspension mod on the GTO


GarageLogic
08-21-2006, 05:24 PM
In a continuation of my series of modifications to the GTO, I bring you my answer to the wheel-hop problems experienced by many, if not all, of my fellow 2004-2006 GTO owners.

As you may be aware, the 2nd Gen GTO has an independent rear suspension, and while it certainly allows for a smooth ride and great cornering, it leaves something to be desired in regards to straight-line acceleration. It seems that the preferred solution to help reduce or eliminate the wheel-hop issues is to install a set of airbags between the rear coil springs to provide better weight transfer. These “drag bags” as they are known in the field, seem to be a tried and true solution, but the pain-in-the-butt install procedures (several hours) and price ($125-$179 and busted knuckles) seemed a little high to me to justify for my periodic quarter mile/eighth mile blasts.

At this point, I began to look at exactly what the bags did and see if there was a simpler solution. From all indications, the bags are simply filled with air which, in turn, effectively increases the rear spring-rate. This increased spring rate helps get the rear tires planted on the launch and greatly reduces the tendency of the rear end to “bounce” around.

My solution. I installed a set of coil-spring helpers you can buy at any parts store for around $15. It took me a total of 5 minutes per side to install them and it has significantly reduced the amount of wheel hop I was experiencing prior to their installation. When I get to the track, I am going to try a few passes with them, and then a couple without just to see what the net effect is.

BenS
08-21-2006, 06:12 PM
Don't those pop out when the suspension flexes out, like when the car is on a lift or hits the top of a rise?

GarageLogic
08-21-2006, 07:18 PM
Don't those pop out when the suspension flexes out, like when the car is on a lift or hits the top of a rise? I'm sure they could but I don't think that is too likely. I had the suspension "flexed out" when I installed them, so unless I take a high speed drive through the streets of San Francisco, I doubt my suspension will see that much travel.

juztinvez
08-22-2006, 12:46 AM
still no makey sensey need pictures. c'mon you used to be good about taking pictures of projects on the mustang, what happened? GTO photo shy?

is there a sleeve of some sort or a collar to hold it in place?

Jason
08-22-2006, 02:02 AM
still no makey sensey need pictures.
It's basically just a wedge that goes in the spring to stiffen it.

Ashley P
08-22-2006, 08:29 AM
At this point, I began to look at exactly what the bags did and see if there was a simpler solution. From all indications, the bags are simply filled with air which, in turn, effectively increases the rear spring-rate.

Or the change in suspension geometry is what kills the hop. I can't believe an independant rear car has a hop problem.

Cool that you fixed it for cheap...you could be a real GTO man after all! :D

ReefBlueCoupe
08-22-2006, 09:43 AM
I can't believe an independant rear car has a hop problem.
:D

You can't?

I take it you've never seen a 99 or 01 Cobra at a dragstrip then :lol:

I saw one wheelhop so bad the trunk popped open. The rest hopped as bad, but the trunk didn't open.

Cheap IRS just blows.

juztinvez
08-22-2006, 09:54 AM
you could have just got a stiffer sway bar to install for drap days or even better an adjustable one if they make it.

bingo:
http://www.hotchkis.net/cgi-bin/EDCstore.pl?user_action=detail&catalogno=2278

156% stiffer

Ashley P
08-22-2006, 10:16 AM
You can't?

Cheap IRS just blows.

I was just thinking of all the corvettes I've seen launch very well, not hop, and all the solid axle A and G body GM cars that hop 'till you lift sometimes!

ReefBlueCoupe
08-22-2006, 11:32 AM
The Corvette's transverse leaf spring suspension is vastly superior to anything Ford has put out short of the suspension on the GT. Hell, the new GT500 has a solid axle :lol:

JWebb
08-22-2006, 08:47 PM
you could have just got a stiffer sway bar to install for drap days or even better an adjustable one if they make it.

bingo:
http://www.hotchkis.net/cgi-bin/EDCstore.pl?user_action=detail&catalogno=2278

156% stiffer

Sway bars don't fix wheelhop.. More than likely, it will just make both side wheel hop evenly.

juztinvez
08-22-2006, 11:25 PM
^^^ makes sense I just remember people saying the hotchkis bars were so stiff they eliminated some of the independent susp characteristics but that was in a handling regard and not a launch. considering the swaybars stiffen the spring rate by transfering the from left to right not front to rear. carry on with your business.

Jason
08-22-2006, 11:26 PM
I was just thinking of all the corvettes I've seen launch very well, not hop, and
C5s hop like a mofo if they're not just spinning.

tooslow
08-23-2006, 01:20 PM
C5s hop like a mofo if they're not just spinning.


Yep. Alot of the Z06 guys were putting a full set of polyurethane bushings on, to help with the horrible wheel hop issue.

Ashley P
08-23-2006, 03:03 PM
I guess wheel hop is OK compared to "car hop", you know, bunny hopping on clutch dump.:rolleyes: Have you seen my TA on a bad leave? :yuck: :barf:

magracer
09-01-2006, 08:22 PM
I have zero wheel hop with the addition of stiffer king springs and koni shocks.

COSWORTH
09-17-2006, 11:56 AM
I think the dash in my 05 is going to come out even with minor wheel spin


Gotta get the upper and lowers in this car replaced