GXP FE3 Suspension not the FE3 from ZOK as advertise by GM

[jimbo]

Originally Posted by RobL Did your original car have the clutch diff? Going from a car that didn't have one to a car that does have one would explain everything that you describe (this is why the Elise originally did not come with a diff). FYI, the diff tries to keep the car pointed straight by making the rear tires move at the same rate. It feels different than an open diff that has no such restriction so the open diff allows more turning freedom.

birdliver also said his GXP feels like it has noticeably more body lean than his base car. I don't think LSD would be the cause of this feeling.

[RobL]

Originally Posted by jimbo birdliver also said his GXP feels like it has noticeably more body lean than his base car. I don't think LSD would be the cause of this feeling.

Technically he said "bit of roll" which could mean anything including having to dial in more steering to get the same amount of turning. However, according to birdliver, he did not have a diff in the original car and that would explain the "dead on center feel" that he described. The only real cure for that is to drive harder and to be on the gas more through the turns.

[Krazed Kanary]

Originally Posted by jimbo To be perfectly honest, I don't know what to think about the GXP's handling at this point... We have very credible people reporting that the GXP just does not handle as well as the base car, wearing the same tires in the case of LV, and wearing better tires in the case of birdliver (GS2s over lousy RSAs). We also have magazine reviews where the GXP achieved lower gs on a skidpad than were achieved for the base Solstice. Being that I will be buying a GXP, the thought of it being inferior in handling to the base Solstice makes me a bit unhappy. That said, I am only unhappy on paper, since I simply can't see driving my car at 9/10s or up on the street and I won't be taking it to a track. So I am saying, I'm unhappy that the GXP's bench racing handling character may be inferior to the base Solstice's bench racing handling character. That said, what I am hearing is that the car "feels" like it handles worse than the base car. The question is, are your cars really inferior at handling and roadholding than the base Solstice? Do any of you really know. My point goes back to when RODEO thought his MSM was a fast car because it "felt" like such a fast car. This is very important to the driver. You want the car that feels best, that feels like it handles the best. You can't discount that what you feel becomes your reality. But when you guys say the car doesn't handle like your base car, are you saying that corner you took at a steady-state 70 mph in a stable 4-wheel drift in your base car is causing your rear tires to break loose as the car begins to spin? Are you saying that the limit of adhesion of your GXP occurs at lower speeds under identical conditions as your old base cars? Are conditions identical? Did you get up to speed much faster on that short straight section in the quick GXP and have to hit the breaks a bit harder on entering that corner, unloading the rear end? That is the kind of thing that is possible. I know you will swear on a stack of bibles it is not like that. And both of you are very credible, and if you are really going into the same corners with the same entry speeds and the same braking force you did when you drove your base cars through those corners, then I absolutely believe the both of you. But I still have to ask, if you didn't drive your base car to the limit of its adhesion and then drive the same corner to the limit of the GXP's adhesion and get different speeds when the car's tires exceed their limit of adhesion, then what does it mean to say that the GXP does not handle as well as the base car? Again, this is all academic to me since I'm reasonably sure the car will handle way, way, way better than my pathetic ability to drive it. And this is all academic to you because it really doesn't matter how well the GXP handles if it doesn't feel that it handles as well as the base car. Really, how it feels is all that matters to you. Feeling stable taking a corner at 70mph is more important to you than feeing like the car is loose at 70mph, even if your tire's reserve is actually equal in both cases.

The buttdyno is notorious for being unreliable, and the driver's skilled/unskilled inputs have much more affect on both perceived and actual handling of the car. That is demonstrated all the time in AX where two drivers driving the same car will be several seconds apart in times. Typically what feels like your fastest run often is not because radical moves "feel" faster to the butt-o-meter but smooth inputs that feel slower are usually quicker. I especially believe that phenomenom is at work when it is claimed that the GXP does not handle as well as a base Soli. The car's additional capabilities are likely creating more forces that in turn exceed the driver's comfort level.

[mena661]

Are conditions identical? Did you get up to speed much faster on that short straight section in the quick GXP and have to hit the breaks a bit harder on entering that corner, unloading the rear end? That is the kind of thing that is possible.

I think this maybe the issue here.

[SolsticeMan]

Originally Posted by Krazed Kanary The buttdyno is notorious for being unreliable, ....

Like this butt dyno?
http://kalecoauto.com/index.php?main...products_id=41

[snaponbob]

Can the difference in "feel" be a function of the added weight being almost all on the front? If my memory is correct, the ZOK is about 200-250 pounds lighter than a GXP (A/C, turbo, intercooler, etc.) and it is all on the front. Skid pad numbers would certainly be effected.

SolsticeMan, the ButtDyno you referenced only functions properly after entering the Matrix.

[ender]

Move the battery to the trunk, where there's plenty of roo...

OK... maybe switch to a compact battery and stash under a seat or in the trunk.

[SolsticeMan]

Originally Posted by snaponbob Can the difference in "feel" be a function of the added weight being almost all on the front? If my memory is correct, the ZOK is about 200-250 pounds lighter than a GXP (A/C, turbo, intercooler, etc.) and it is all on the front. Skid pad numbers would certainly be effected. SolsticeMan, the ButtDyno you referenced only functions properly after entering the Matrix.

I can't remember which thread I responded to, but my quickie checks show a Z0K around the mid 2800 lbs (call it 2850) at about 52-1/4 % front. Most of the GXP's are low 3000 lbs, call it 3025, at about 53% front.

That's 175 lb difference. About 105 lbs of that is added to the front axle, 70 lbs of that to the rear axle. All of the GXP's I have weights on have AC. The single Z0K I have a weight on does not.

All of the GXPs also have power options. The Z0K does not.

A handful of base solstices for which I have weights are closer to 2900 lbs or sometimes a bit higher if it has all the options and goodies. Auto trans adds another 20-30 lbs (I haven't actually figured it out, just what I was told).

[SolsticeMan]

Originally Posted by ender Move the battery to the trunk, where there's plenty of roo... OK... maybe switch to a compact battery and stash under a seat or in the trunk.

Hmmmm.... yet ANOTHER reason to advance battery technology into the future...

How 'bout a 'structural battery'? If you have some structural member, (like the wasted spaces at the rear of the car) put custom designed structural members that also have battery cells in them....

[jimbo]

Originally Posted by Krazed Kanary Typically what feels like your fastest run often is not because radical moves "feel" faster to the butt-o-meter but smooth inputs that feel slower are usually quicker.

AMEN!

Now, all that is not to say that the GXP does handle as well as the base Solstice. I just don't know. But the butt dyno is not the right method to guage that difference. The same driver really has to drive both cars to the limit on the same curves under the same ambient conditions to say whether the handling differs or only "FEELS" like it differs.

Again, to people driving cars on the street, handling feel is the only important consideration. Actual handling doesn't mean to much since every sports car can handle better than anyone can use on the street. I think this is why the MX-5 fans think it handles better than the Solstice. Because the Solstice has a heavier Vette-like handling feel to the MX-5s more nimble handling feel, they conclude the MX-5 handles better than the Solstice, yet we know the Solstice is every bit the equal to the MX-5's handling capability.

[todd_raleigh]

Originally Posted by Krazed Kanary I have autocrossed on street tires/less than 10 times

I represent that remark!

Seriously, I had the base Sol and then bought the GXP. The first two things I noticed immediately were:

1) The GXP is a hell of a lot faster than the base
2) The GXP does NOT handle as well around corners. This was discussed in threads with bird, myself (we received our cars within a day or two of eachother), and others.

I don't know why the GXP doesn't have that same go-kart point and follow feel, but it doesn't.

These posts have been very interesting, but we don't know the real reason. I would certainly like to get that go-cart feeling on the GXP. Kanary mentioned the rubber. That may be my next step as I continue down my AX experience.

[ender]

When people talk about the superior handling of the 'base car', are they talking about the non turbo car with the Z0K suspension or the non turbo car without Z0K?

[RobL]

Originally Posted by ender When people talk about the superior handling of the 'base car', are they talking about the non turbo car with the Z0K suspension or the non turbo car without Z0K?

I'd be more curious about with diff or not. Like I mentioned above, with the clutch diff in the car, it will tend to have a little more understeer than one with an open diff. It will also have a solid on center feel, the opposite of a go-cart. Driving with the clutch diff does require you to drive more agressively and slip the car around a little more than the carving that can be done with an open diff. I used to play around in SM2 and had 3 different diffs in that car until I found one that I liked.

[LatinVenom]

Jimbo:
To answer one of your question the test was done entering a curve at a specific speed, meaning the desire speed was attained on the straight of way prior to entering the curve, at no time was the brake applied, both of my cars had LSD, the GXP feels as though the back end is straining vs the N.A. car feels flat.
Same thing happens with 90 degree turns, at a specific speed the GXP tires will start to squeal vs the N.A. car does not.
You know from the very beginning I'd complained about the difference in feel of the handling on the GXP, I thought the tires could be the problem and upgraded to the same tires, but although it improve some what it does not match the cornering feel and abilities of the N.A.

[Krazed Kanary]

I am assuming we are discussing the NA without ZOK since I have not seen anyone besides Fast Mike say they have a ZOK package car, and the member's join dates are mostly pre ZOK. I just cannot buy the assertion that the non ZOK would outhandle the GXP, given the same conditions Our 99 Miata was fully prepped including 2500.00 custom built shocks and 99 is considered to be the best handling of all the years, but for a fact our stock suspended GXP outhandles it.
I have to agree with Jimbo that the difference is likely one of perception rather than actuality.

SM our GXP (zero option except AC) actual weight was 2944 with catback and 1/4 tank of gas.