: Lowering a CTS-V



UBNZO6D
12-16-09, 09:43 PM
Been trolling here for a while, nice site...I have a ZO6 and you're able to lower them by adjusting some stock bolts...Can a similar procedure be done to a V...

Thanks in advance

Greg

Dr. Design
12-16-09, 09:46 PM
Hello Greg,
The ZO6 and the XLR both use the same lowering methods. Unfortunately the CTS-V will require actual lowering springs to properly lower the vehicle.

We have some prototypes out there right now. Release is scheduled for January release.

Thank you,

Dr. Design
D3 Cadillac


Been trolling here for a while, nice site...I have a ZO6 and you're able to lower them by adjusting some stock bolts...Can a similar procedure be done to a V...

Thanks in advance

Greg

wfo
12-17-09, 10:37 AM
If it were as easy a spring kit, suspension giants and Tuner giant; ones that I've spoken with like Hennessy, H&R, Eibach would be all over this in a heart beat.

The problem I'm hearing from the aformentioned, is, the Magnetic Ride Control (M.R.C.) and how it functions. The M.R.C. system is vastly different than a traditonal shock or Coilover system.

From the aftermarket perspective, the spring rates, height and size of spring(s) created to this point have compromised/inhibiting the M.R.C.'s ability to do it's full range dampening.

Given that GM spent millions on research, development and implemention of the M.R.C. system, it's going to take some sauvvy engineering to figure this one out.

If D3 can pull this off, they'll certainly be the first. To date they've gone on record as saying it was in Europe being tested and on it's way over will be available in Oct 2009. I'd love to see this work out and finally get my ride looking right while maintaining all that GM did on the engineering side.

If it was an easy fix like many domestic cars I'd dump the shocks put a high quality set of coilovers like I did on my 08 Z06 and call it a day... except the M.R.C. is just that good.

thebigjimsho
12-17-09, 12:46 PM
If it were as easy a spring kit, suspension giants and Tuner giant; ones that I've spoken with like Hennessy, H&R, Eibach would be all over this in a heart beat.

The problem I'm hearing from the aformentioned, is, the Magnetic Ride Control (M.R.C.) and how it functions. The M.R.C. system is vastly different than a traditonal shock or Coilover system.

From the aftermarket perspective, the spring rates, height and size of spring(s) created to this point have compromised/inhibiting the M.R.C.'s ability to do it's full range dampening.

Given that GM spent millions on research, development and implemention of the M.R.C. system, it's going to take some sauvvy engineering to figure this one out.

If D3 can pull this off, they'll certainly be the first. To date they've gone on record as saying it was in Europe being tested and on it's way over will be available in Oct 2009. I'd love to see this work out and finally get my ride looking right while maintaining all that GM did on the engineering side.

If it was an easy fix like many domestic cars I'd dump the shocks put a high quality set of coilovers like I did on my 08 Z06 and call it a day... except the M.R.C. is just that good.
Yeah, I saw my FG2s fail in about 35,000 miles and I believe that was partially due to being lowered via GC coilovers.

On such a sophisticated damping system, I am VERY leery of lowering on these. And I don't want to ditch the system for the sake of lowering. Unless it doesn't affect ride and Luke can set me up with a couple spare sets for cheap, I'm not changing. Unless you can play with the shock housings or mounting points, I don't see it...

Vrocks
12-17-09, 02:00 PM
I'm wondering if the system would artifically firm up when a shorter spring is installed.

If the suspension has 5" of travel and we lowered the car 25% (1.25"), would the system interpret that as the car having a load of people or cargo in it? Would that lead to it firming up, to try to avoid hitting the bump stops?

I'd have to guess that the bigger problem is getting the right damping rate for the shorter firmer spring. I think the fluid being thicker (assuming this happens if it thinks there's a load in the car), would naturally help with a more agressive spring / coil. The only side effect I can think of (if the system was correctly balanced) would be increased heat in the fluid. Which would be caused from it being in a thicker state than normal, and from the spring pushing back with more force.

I remember reading that the first gen mag ride suspensions weren't used in heavy vehicles or cars intended for track use, due to heat problems... I'd have to guess that daily driving wouldn't create enough heat to damage a slightly lowered suspension.

Or, maybe you could change the voltage being fed to the fluid? Either via resistors or by reprogramming the module responsible for the suspension.

wfo
12-17-09, 02:36 PM
Bingo!

Vrocks onto what we're up against, and that is, a much more complex achievement than installing a spring kit as we would do in lowering most cars. The mere making a set of springs of an arbitrary percentage higher/lower spring rate won't work without sending the wrong message to the MRC.

Hennessey is currently machining the A arms and will send you the specs if you call them. You'll just need to know a good machinist or have them do it. Outside of that, we'll just need to be patient until someone in the suspension engineering think tanks figure something out. Like PFADT. With more time these cars will have more goodies.

thebigjimsho
12-17-09, 03:31 PM
How about machining the front shock rods and doing a MIGHTYMOUSE V1 type mod to the rears on the V2?

chopmeat
12-17-09, 11:21 PM
D3, nice to hear that they are coming!!!!!
YEAH!!!!!!!!!!!!!!

thebigjimsho
12-18-09, 12:02 AM
D3, nice to hear that they are coming!!!!!
YEAH!!!!!!!!!!!!!!
You gonna do aftermarket shocks with those springs?

chopmeat
12-18-09, 06:15 AM
You gonna do aftermarket shocks with those springs?

Probably not, it depends on how low the drop is.
I actually have my stock springs cut now.
I know it's not really the right thing to do, but I always do it and it looks too darn cool!!!!

wfo
12-18-09, 07:58 AM
Chopmeat...

How does it drive?

What does the ride feel like?

chopmeat
12-18-09, 12:42 PM
It's perfect, just like stock, everything works.


http://i255.photobucket.com/albums/hh157/knihc_photo/stockcut2.jpg

vseries
12-20-09, 01:16 AM
It's perfect, just like stock, everything works.


http://i255.photobucket.com/albums/hh157/knihc_photo/stockcut2.jpg

The ride is just like stock?? I find that hard to believe.

wfo
12-20-09, 08:58 AM
Chopmeat..that car looks great, really does.

My concern though, is this. If everything is perfect and works like stock as you say, what's everyone talking about with regard to ride quality compromise and the Magnetic Ride system not being able to function properly? :hmm:

chopmeat
12-20-09, 10:12 AM
Why is that so hard to believe?? Lol
It rides exactly the same just like it did before and EVERYTHING works like I said.
It's perfect!
It's not really cut that much belive it or not.
The pic looks low, but my Eibach's that I installed previously were much lower.
I would like that look again.

radix
12-20-09, 01:17 PM
Chopmeat..that car looks great, really does.

My concern though, is this. If everything is perfect and works like stock as you say, what's everyone talking about with regard to ride quality compromise and the Magnetic Ride system not being able to function properly? :hmm:


You need to recognize that "function properly" has a wide range of meanings depending on what each person thinks is important.

By cutting the springs, Chop has too low a spring rate for the remaining suspension travel, and the MR system is not calibrated for new spring rate either. So what does this mean ? Maybe nothing, depending on what is important to you. His car certainly has inferior handling, compared to the std car on a road course. His car will have higher than normal loads on the bump stops under high loading conditions, at some point this could even lead to suspension damage.

But for daily driving on normal smooth roads ? There is no reason to think it wouldn't feel fine (and likely better than the "correct" shorter/higher rate springs) Chop clearly puts a higher value on getting the look he likes and so the compromises in performance he gets makes sense.

The MR system uses accelerometers and/or travel sensors to adjust the damping rates. The algorithms behind these sensors rely on knowing the characteristics of the car - and based on the sensor readings and driver preference setting trys to keep the tires on the road and a flat vehicle attitude. The goodness of these algorithms and calibrations is ultimately mostly subjective - so with most changes like this, it is unlikely the system will fail or simply not function, rather anyone making such changes should just recognize that the performance will no longer reflect the intent of the developers.

thebigjimsho
12-20-09, 01:26 PM
You need to recognize that "function properly" has a wide range of meanings depending on what each person thinks is important.

By cutting the springs, Chop has too low a spring rate for the remaining suspension travel, and the MR system is not calibrated for new spring rate either. So what does this mean ? Maybe nothing, depending on what is important to you. His car certainly has inferior handling, compared to the std car on a road course. His car will have higher than normal loads on the bump stops under high loading conditions, at some point this could even lead to suspension damage.

But for daily driving on normal smooth roads ? There is no reason to think it wouldn't feel fine (and likely better than the "correct" shorter/higher rate springs) Chop clearly puts a higher value on getting the look he likes and so the compromises in performance he gets makes sense.

The MR system uses accelerometers and/or travel sensors to adjust the damping rates. The algorithms behind these sensors rely on knowing the characteristics of the car - and based on the sensor readings and driver preference setting trys to keep the tires on the road and a flat vehicle attitude. The goodness of these algorithms and calibrations is ultimately mostly subjective - so with most changes like this, it is unlikely the system will fail or simply not function, rather anyone making such changes should just recognize that the performance will no longer reflect the intent of the developers.
Excellent post...

chopmeat
12-20-09, 04:44 PM
Listen, you make a lot of sense...
BUT...

If you are going to be a suspension nerd and freak out about everything don't do it!!

IMO It's such a small amount of stress that hey, who cares?
Some guys are just soooo fearful!!!!!!!!!!!
If your A$$ can actually tell the RIDE difference of dropping the car an inch then you have ONE TALENTED BUTT!!!!
LOL

Ross L
12-20-09, 04:59 PM
I like your attitude chop! Someone has to eventually try things instead of debating and discussing.:thumbsup: Full steam ahead:highfive:
Ross

thebigjimsho
12-20-09, 05:34 PM
I like your attitude chop! Someone has to eventually try things instead of debating and discussing.:thumbsup: Full steam ahead:highfive:
Ross
In other words, we'll hang tight while you be our guinea pig. Always works for me...

radix
12-20-09, 06:01 PM
If your A$$ can actually tell the RIDE difference of dropping the car an inch then you have ONE TALENTED BUTT!!!!
LOL

I think any of the track day guys here could tell in a matter of seconds (turns) that the springs are cut to lower an inch.

While an inch seems small, these cars only have about 3.5-4" of compression travel to start with - so taking out an inch of travel is 25-30%+ (a lot). Further, I don't know the free length of the springs, but let say they are 12+" or so - your cut won't increase the rate by much to compensate.

What this means is that on some serious twistys or corners with elevation changes, bumps, etc. It is going to be 20%+ easier (lower forces/speed) to get on the bump stops with all of the non-linear behavior that that entails.

Driving normally on the boulevard it would be hard to tell, driven hard, quite easy IMO.

Short-Throw
12-20-09, 07:52 PM
I think any of the track day guys here could tell in a matter of seconds (turns) that the springs are cut to lower an inch.

Driving normally on the boulevard it would be hard to tell, driven hard, quite easy IMO.

radix understands it pretty well.


If your A$$ can actually tell the RIDE difference of dropping the car an inch then you have ONE TALENTED BUTT!!!!
LOL

One inch can easily be felt on the track Furthermore, Your a$$ is one of the three things on your body you actually use to feel what the car is doing. You a$$ (and back) tell you exactly when a car is exhibiting oversteer, among other characteristics. Taking a mere 1/4 inch off a spoiler would amaze you on high speed stability.

Mike

chopmeat
12-20-09, 09:30 PM
Look, to each his OWN.
One of the posts was talking about algorithms...
Are you kidding me, what is this the space shuttle?
:thepan:

DrewDog
12-20-09, 10:48 PM
Look, to each his OWN.
One of the posts was talking about algorithms...
Are you kidding me, what is this the space shuttle?
:thepan:



:bwahaharoll4vu:

TrevorD
12-20-09, 11:11 PM
Look, to each his OWN.
One of the posts was talking about algorithms...
Are you kidding me, what is this the space shuttle?
:thepan:

LMAO!

It's your car. If it makes you happy, do it.

Short-Throw
12-20-09, 11:55 PM
Look, to each his OWN.



LMAO!

It's your car. If it makes you happy, do it.

I couldn't agree more guys! :thumbsup: Just pointing out the pros and cons!

thebigjimsho
12-21-09, 12:30 AM
Yep, algorithms are garbage. They mean nothing...

musclesbmf
12-21-09, 10:27 AM
I'm with chop on this... too much over thinking the suspension. Again, to each his own. I was the first to do the Eibach's and I still have them installed (10 months) and the car is "slammed" on 20 inch wheels. Car drives fine, sport and tune rides still work the same and the car looks mean. I don't track the car and never will so can't comment on all that. I like fast and I like looks. Now I have it :-)

Mark

thebigjimsho
12-21-09, 12:59 PM
And I always have it. :yawn:

wfo
12-21-09, 03:56 PM
If you're telling me it rides perfect, I've got to believe it.

1. How much did you cut the springs?

2. Could you measure please, from the floor to the "center bottom lip of the fender well just above the tire" on both front and rear fenders, please?

I would greatly appreciate that when you get a chance.

thebigjimsho
05-28-10, 07:29 PM
Yep, algorithms are garbage. They mean nothing...
hmm...

mugatu22
05-29-10, 02:39 AM
hmm...

You've been especially insightful tonight w/your "hmmm"s...not much more to say, I agree.

thebigjimsho
05-29-10, 08:53 AM
How about machining the front shock rods and doing a MIGHTYMOUSE V1 type mod to the rears on the V2?
I'll ask it again. For the V1, some had machined an extra groove for the stock snap ring to move down, bringing the perch down to lower the front of the vehicle. On the rear, a MIGHTYMOUSE type mod where you add a plate to the rear shock mount to bring the mount higher and thus lower the vehicle without changing anything else might be an option. Maybe?

On each, you change the height without changing spring rates or suspension travel...

Mike 09 V
05-29-10, 06:09 PM
Not being an engineer and all that, changing the suspension on a vehicle that is capable of traveling over 150 MPH easily, could be a recipe for disaster. Of course there is the possibility that nothing could happen to you since you don't intend to track the car, but the next owner may try it, or someone could have their kids in the car and try something that could turn out all bad.
FWIW
Mike