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I do not know which way to go here. Is one better than the other? Based on price the ZOK must be better...Yes? Thanks!
 

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If you are going to do any autocross then get the ZOK.
To my knowledge no one has made a real world comparison of this products.
 

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I do not know which way to go here. Is one better than the other? Based on price the ZOK must be better...Yes? Thanks!
I have driven a Sol that had the ZOK suspension.... very nice handling.

My Sol had the DDM Backbone and the ProBeam ... both substantially changed the handling.

When I questioned a GM suspension engineer about the ProBeam he did state (IIRC) that it would effect the handling but not as much as the ZOK suspension.

Like LV said .. if you are looking to autocross, then yes, go with the ZOK. But, if you are just looking for an inexpensive way to improve the handling and something you can install yourself w/o a lot of hassle, go with the Backbone and ProBeam. Nice thing is you can start w one (I started w the backbone) then add the ProBeam later. Either will give you a noticeable difference.
 

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If you are going to do any autocross then get the ZOK.
To my knowledge no one has made a real world comparison of this products.
Hmm... not sure I would say that.

Maybe this though:

IF you are going to autocross in a STOCK class, then get the Z0K, as it's your only legal option.

IF you are going to autocross in any other class, either is fine for the activity.

What do I base this on? There were only three Kappa's (Alex's, Bob's, and Mine) running in Street Prepared at Nationals, and NONE of us have the Z0K setup. In fact, Alex doesn't even have the ProBeam, but Bob and I both do... yet we can't (legally) install it fully (can not fasten to the differential carrier).

If money is no option, run the Z0K.
If you are going to autocross, use the least expensive legal option for your class.
 

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Discussion Starter #5
Thanks everyone. I will be road racing my GXP. I need all of the suspension benefits I can get. Looks like the ZOK cross brace is the winner. Thanks!
 

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Hmm... not sure I would say that.

Maybe this though:

IF you are going to autocross in a STOCK class, then get the Z0K, as it's your only legal option.

IF you are going to autocross in any other class, either is fine for the activity.

What do I base this on? There were only three Kappa's (Alex's, Bob's, and Mine) running in Street Prepared at Nationals, and NONE of us have the Z0K setup. In fact, Alex doesn't even have the ProBeam, but Bob and I both do... yet we can't (legally) install it fully (can not fasten to the differential carrier).

If money is no option, run the Z0K.
If you are going to autocross, use the least expensive legal option for your class.
Rich - So you use the Probeam as a stiffener across the frame rails but not connected to the differential carrier? Isn't the Z0k piece connected to the differential carrier so that it supports the differential? I'm asking because I was under the impression that the 2 serve 2 different functions: The Z0k piece carries the differential and acts as a frame crossmember while the Probeam is only a cross-member or a stiffener for the rear of the frame?
Are the 2 functionally the same when the Probeam is connected to the carrier?
When using the Probeam, is the stock cross-member retained or does the Probeam take the place of the stock cross-member?

Thanks,

Yogi
 

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Rich - So you use the Probeam as a stiffener across the frame rails but not connected to the differential carrier? Isn't the Z0k piece connected to the differential carrier so that it supports the differential? I'm asking because I was under the impression that the 2 serve 2 different functions: The Z0k piece carries the differential and acts as a frame crossmember while the Probeam is only a cross-member or a stiffener for the rear of the frame?
Are the 2 functionally the same when the Probeam is connected to the carrier?
When using the Probeam, is the stock cross-member retained or does the Probeam take the place of the stock cross-member?

Thanks,

Yogi
They are doing much the same thing. The Z0K replaces the carrier with one that has extra-stiffening welded to it. The Probeam is itself the extra stiffening and bolts to the carrier at the ends and with three bolts along the length. Comments I've seen have talked about DDM talking & running with GM engineers who've commented that the Probeam is just as good as Z0K. However to be legal in autox stock (I don't understand why) you can use the Z0K, or the Probeam without the three bolts along the length, and removing those will reduce it's efficacy below that of the Z0K.
 

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Rich - So you use the Probeam as a stiffener across the frame rails but not connected to the differential carrier? Isn't the Z0k piece connected to the differential carrier so that it supports the differential? I'm asking because I was under the impression that the 2 serve 2 different functions: The Z0k piece carries the differential and acts as a frame crossmember while the Probeam is only a cross-member or a stiffener for the rear of the frame?
Are the 2 functionally the same when the Probeam is connected to the carrier?
When using the Probeam, is the stock cross-member retained or does the Probeam take the place of the stock cross-member?

Thanks,

Yogi
The ProBeam doesn't stiffen across the frame rails... not literally at least. The connection point is the forward box connection at the lower control arm on each side of the vehicle. So, yes, it stiffens across the vehicle (side to side), but not connected to the "rails".

The Z0K member replaces the stock member and acts as a differential support as well (the diff mounts to this cross member). The Z0K has the welded plate that TomatoSoup spoke of, which is what provides for the extra stiffening vs. the stock crossmember.

While the stock and Z0K crossmember both provide a mounting point for the differential, I wouldn't say they serve a different purpose than the ProBeam, but they provide an additional function that the ProBeam alone can not... mounting the rear differential. The Z0K crossmember vs. the stock crossmember difference is what the ProBeam mimics in it's own way.

While I can't say for certain what the added stiffness is with the Z0K crossmember or the ProBeam, I would say "yes", if you installed the three long bolts from the ProBeam through the crossmember then it acts essentially the same as the upgraded Z0K crossmember. One might be "stiffer" than the other, but I can't say if that's the case.

When installing the ProBeam (recommended install or autocross legal install) you retain the stock Crossmember. It is simply an addition to the vehicle to mimic the welded plate added on the Z0K crossmember vs. the stock crossmember.
 

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However to be legal in autox stock (I don't understand why) you can use the Z0K, or the Probeam without the three bolts along the length, and removing those will reduce it's efficacy below that of the Z0K.
I'll try to clear up the rules issues for autocrossing. This isn't a quote from the rules, but my understanding of them.

In stock class you can not make adjustments to the rear suspension components (sway bar, strut tower bar, etc.) which cross the width of the vehicle. Since the Z0K is a factory option, you can install this option on a vehicle which was not delivered with the option and still be "stock". Hence the Z0K crossmember becomes legal, where adding in the ProBeam would not.

As to why you can not install the ProBeam to the crossmember, the rule states that in non stock classes (which allow for these sorts of suspension changes) you can only fasten / mount at the suspension pickup points. Since the crossmember is not part of the suspension, as defined by the rules, you can not mechanically tie the two pieces together.

Don't ask me why the rules are the way they are though... but that's how they are written and why things are / are not legal in various classes.

For the record you can use the Z0K crossmember in any autocross class... it's just more expensive than the ProBeam, so when you don't have to be stock, why spend the extra money and time for the install?
 

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rlhammon to stay in stock class dont you have to add the total ZOK option? I did not think you could just add some of the parts.
 

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Thanks for the feedback, Soup and Rich! Much appreciated!

One more question: Are the Z0K parts legal on the Sky or only on the Sol?

Thanks! :thumbs:

Yogi
 

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rlhammon to stay in stock class dont you have to add the total ZOK option? I did not think you could just add some of the parts.
I did say the Z0K option in my post.

rlhammon said:
Since the Z0K is a factory option, you can install this option on a vehicle which was not delivered with the option and still be "stock". Hence the Z0K crossmember becomes legal, where adding in the ProBeam would not.
I kept the discussion on topic (crossmember) so as not to stray to other parts of the "option" package.

So... yes, you are correct, and yes... that's what I said (or at least was trying to).
 

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rlhammon guess I have to read the posts a little better you did say option sorry about that
 

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rlhammon guess I have to read the posts a little better you did say option sorry about that
No problem.. you were just looking out for everyone and making sure good and correct information was being shared. Thanks for that.
 

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For Autocrossing in the Stock Class, what would be the minimum parts necessary to satisfy the term Z0K 'option package' being added to a GXP?

Since you can use any shocks or front bar I'm guessing you need the four springs, rear bar, and the rear support. Is that correct? And you HAVE to use ALL of these?

And I was told the Z0K suspension did not come in cars with leather or a/c. If that is the case can it legally be added to my car which is fully optioned and still be legal for stock? And I'm talking at National Tour events.

Thanks!!
 

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For Autocrossing in the Stock Class, what would be the minimum parts necessary to satisfy the term Z0K 'option package' being added to a GXP?

Since you can use any shocks or front bar I'm guessing you need the four springs, rear bar, and the rear support. Is that correct? And you HAVE to use ALL of these?

And I was told the Z0K suspension did not come in cars with leather or a/c. If that is the case can it legally be added to my car which is fully optioned and still be legal for stock? And I'm talking at National Tour events.

Thanks!!
required:
25849163 Front Spring (x2)
25855626 Rear Spring (x2)
25919110 Rear Stabilizer Shaft
25855623 Rear Stabilizer Shaft Insulator (x2)
25855624 Rear Stabilizer Insulator Clamp (x2)
25877302 Rear Suspension Support Crossmember

optional:
25919109 Front Stabilizer Shaft

caveat:
not sure if these part numbers are still valid. but they're still in the system and you can buy 'em new the last i heard. tom @ crateenginedepot is an excellent source.

as for Z0K on a non-factory ordered car w/ leather & a/c - don't worry, comfort & convenience covers that. it's what most of us run @ nats anyway, myself included.
 

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Can both be run together? Can the Kappasphere be added to those. Stiffer is better!
 
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