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Go back and read my posts in this thread... the tires on the GXP are NOT the same as those you can get from your local Bridgestone dealer. They are an entirely different animal and, per the former product manager, who lives in the Detroit Metro area, they are/were fine in snow last winter. He also made the comment that, if they had to do it again, they'd make sure the tires were certified "all-season".
--Robert
The car was fine in a straight line at 30-40 mph but gave me two unpleasant suprises. Turning from a stop created a plow (terminal understeer) that the stab control tried to fix. Anyone with front drive experience knows to get off the gas in this circumstance but my correction and the computer's correction were in conflict.
The traction control and the anit-lock works fine and all the time.
In these conditions which are more favorable than snow and 30 degrees ( the ice is more slippery),I got home and passed 4 cars off the road so in that context I am pleased.
However the lateral traction of the front tires is poor especially in a turn. Previous cars 97 GTP and 2001 Regal GS were better in the snow.
I will try these tires one again and then make a decision as to front snows.
On a rating scale of 0 to 5 snow flakes ** 3/4.
Miles: 362
Avg Speed: 79.5
MPG: 23.0
Time: 4 hours 32 minutes 48 seconds
No stop and go at all - straight shot with a few slow downs for big rigs passing others in the fast lane. Used premium fuel (only have used premium since purchasing the vehicle 10/05). Total miles on vehicle 2010. Pushed to 105 mph twice on I-10 during trip. Most of trip was flat, however strong crosswinds most of trip (30-40 mph) and some moderate grade inclines, but mostly flat.
First road trip in the car and very pleased with comfort, noise level and handling. Pleased with mileage (23 mpg is more than acceptable for a V8).
The bad news is that I am afraid it is pretty clear that I will never achieve the highway EPA rating. (Unless the gas mileage improves as I add more miles – though at 7,000+ now, I doubt that.)
I drove from Atlanta to Carrabelle, FL and back. I filled the tank once I cleared the metro area. I filled the tank again at 232 miles (last gas in Georgia) and filled again in Tifton, before re-joining I75 North for the slog home on Sunday PM. (I did not want to count that mileage, as the traffic became bad & worse – as feared \ expected.)
I averaged these 2 fills, since they were not the pumps I typically use – and there are variances. The 2 fills = 470 miles. Total fuel used = 19.35 gal. Average MPG = 24.3. (Excel, not DIC.)
I did not exceed 80 MPH on the Interstate section southbound. Once off the Interstate, the speed limits and (um) aggressive enforcement mean that I find 65 the highest ‘reasonable & prudent’ speed.
A little experimenting with various steady speeds on relatively level roads strongly suggests that DoD is much more likely to engage at 60 – 70 than at any higher speeds. With resulting steep downslope to MPG as speeds rise above 70.
YMMV.
- Ray
Still full of Turkey . .
I hope to have a dealer look at it tomorrow, but here are the symptoms – and anyone who has experienced anything similar, please comment? Or if you just have a guess . . . Thanks!
The symptoms are an apparent attempted and aborted TCC lockup – followed immediately by another such attempt \ failure – and another, continuing until conditions change.
Associated (secondary?) symptom is that the TCC lockup appears to be initiated now at lower speeds than previously.
This has persisted through 2 warm shutdown \ restarts and 1 overnight thorough cooling and cold start this AM.
The motor appears fine, acceleration through first, second and third appears unaffected. Once approaching highway speed and backing off the throttle to a steady speed, the TCC attempted lock \ unlock cycle begins.
What I first noticed was a rather annoying ‘surge’ as I backed off to a steady highway speed. After some experimentation, this surge appears to be a result of the TCC cycle.
I did take the next opportunity to fill the tank, in the off chance that I had some ‘bad gas’. Though this started after almost 100 miles since the last gas tank fill. No effect.
Though this started after a run of about 250 miles in a day, the motor showed normal temp., the trans temp was steady at 192 (I have seen it over 200 with no issues), and no DIC or panel lights or indicators triggered. . .
And I was not pushing the car hard at all.
Any suggestions would be greatly appreciated.
Thanks,
- Ray
Otherwise, quite impressed with the GXP, at 7,000+ miles!!
I experienced the same surge you mentioned, although I think it was always at lower speeds. It definitely seemed TCC-related.
I haven't been able to reproduce it on demand yet, although I haven't tried that hard.
In my case, it hasn't gotten stuck in a loop of trying/retrying. It just happens once and that's it. Hopefully it doesn't progress beyond that, but I'll see if I can reproduce it and let you know what I find.
-Dayne
It beats me why GM didn't get the 4T80 which handles the Northstar V8 pretty well... :confuse:
My understanding is that the 4T80E is:
1 – Significantly heavier than the 4T65E – approx. 295# vs. 215#
2 – Significantly larger in physical dimensions than the 4T65E. The other applications (FWD Caddys and the Bonne GXP w/4.6L V8 Northstar) were based on the larger FWD platform than the GP.
3 – Significantly more expensive to produce than the 4T65E.
With an unlimited budget, I’d expect a 6 speed Manumatic in the GXP. For a relatively low volume ‘niche’ vehicle like the GXP, I am still happy with the decision to go with a stronger version of the 4T65E.
Now – my GXP is in the shop today with an (apparent) trans. issue (see above post) so my happiness may wane, depending on the outcome of this service experience.
It seems at least possible that this might be an electronics \ programming issue. That a re-flash or replacement of a PCM might address. (As opposed to an internal mechanical failure.)
We shall see . . .
- Ray
Still awaiting a call from the Dealer . .
Replacement part = Throttle Body (this was causing the ‘surge’ problem)
Part on the way.
Will also re-program PCM.
Will be ready by 2:30 \ 3:00.
Hmmm.
- Ray
Skeptical, but willing to be convinced . .
"The stab control sucks as every time that I lost lateral or yaw control the computer fought me. Unfortunately there is no way to turn it off. "
Press and hold the TC button for several seconds (5-10) and you should receive a DIC message that stability control is off. I believe you have to restart the car before it will turn on again.
Personally, in the snow, I'd rather learn how to work with the SC than have it off when I suddenly need it.
Edit: Should have read through the thread before replying.
I realized that Pontiac callsese 2006 models. Also note forum caption.
So for those want to repace the stock air filter K & N part number 33-2334 is for a 2006 GXP. Now I'm waiting for a complete airbox replacement but nothing yet on the market.
I have it installed along with several others and it works great.
http://www.pbase.com/pdqgp/image/51992078
http://www.pbase.com/pdqgp/image/51992183
Right now in northern Ohio we are waiting for the next band of lake effect snow so hp doesn't matter hooking up does.
I have a family with a wife and 3 young kids, so I need a decent sized sedan, but want something with some power!
Are your GXP's holding up well for you? Not long ago I wouldn't have even considered a GM car, but my '03 Silverado has been a good truck. Hopefully the Pontiac has decent build quality...
- Galen
Nothing replaced yet. Waiting for more snow.
MPG's won't change regardless of filter or intake. It's more hype and the changes are so small one will never see a result.
Northern OH? email me....I'm from Cleveland area....have a good link for you being an Ohio owner.
Just consider from a family standpoint and three kids....test drive the car, have them all sit in the back and see what you think. There aren't many storage places, cubbies, etc...and my 03 Accord had a more usable back seat. Not that I'm picking on my car, but I don't know that I would buy it if I was regularly hauling three kids. I have one and one on the way, so it's not much of an issue.
Value wise, the Altima is nice, but it's about as common as all get out, and I personally don't see the SE-R holding value like other imports would. Also consider used manual tranny sedans don't sell anywhere near as well and even though it's an SE-R, the 6spd will hurt resale overall. Even new, they don't sell a large number of manuals. That will vary of course depending on your location.
Quality wise, you'll be surprised if you do the research...the Grand Prix has been a great sedan quality wise.
The back seats in my wife's GXP are hard as a rock (front seats as well) compared to our last GTP. That's about my only dislike on the GXP. But the back seats do fold down for a nice pass-through for lengthy cargo.
Overall, the GXP will give you more smiles
I would expect depreciation to be roughly the same, as the 6-speed tranny will reduce resale value (or at least limit the resale market). Hope you buy the GXP!
1. I recommend the all-weather floormats available through GM if you live in snowy/rainy areas. They are heavy duty and engraved with "Grand Prix". $74 total for front & rear.
2. Still no progress on the spare tire. I am raising hell because of the principal of the deal. The vehicle I traded in had a spare, so my new car should have something. I am not letting go on this one, not yet.
3. Fuel economy is all over the place. From 18 MPG up to 24 MPG depending on the weight of my foot. Heard claims it will stay on just 4 cylinders clear up to 80 mph if drove right. Once I get over about 60 mph, the fuel mileage indicator makes me think it is hitting on all 8, so I think GM overstated the fuel economy.
4. Still love the car...the exhaust tone, the power, the looks. Humming from speakers does not bother me...MINOR issue. I wish there was a little more headroom (I am 6'3"). Got a speeding ticket on I-69 in Michigan on Christmas day going 85 mph. It was worth every penny! I intend to keep this sporty family sedan for quite a while.
. . .
Got a speeding ticket on I-69 in Michigan on Christmas day going 85 mph.”
First (if you have not posted recently, you may not have read every post??) I posted some thoughts on fuel economy \ MPG back on # 594 – and more actual observations after a long road trip on # 633.
If the 85 MPH ticket was indicative of your typical, actual highway travel speed – I am not surprised that the most you achieve is 24. I have achieved over 22 MPG for a full tank only twice in over 8,000 miles. Both were close to ‘ideal’ “real-world” conditions. (Sounds like an oxymoron, but what I mean is: In the “real-world”, I am NOT constrained by the EPA test limits on rate of acceleration when I merge or pass or leave a traffic light. In the real world, roads have at least some traffic and I am constrained largely (on Interstates) by local speed enforcement rather than EPA test max speed (still 60 MPH!!) and I am free to drive with my A/C on. ‘Ideal’ conditions mean relatively light traffic, cool enough ambient temps to be comfortable without the A/C compressor running, cool enough that the air is relatively dense, and mostly running on roads with little significant elevation change. And only me in the car, and a weekend case – though with something like 100 pounds of beer in the trunk on the down leg!)
My overall fuel mileage now stands at 19.58. But if I remove the 2 ‘best’ tanks from the spreadsheet, the average drops to 18.76.
Second, I am satisfied with the fuel mileage, given the available performance & how often I utilize it. (Many smiles per gallon, thank you.)
Although I have seen (and quoted here) that GM states DoD can function at up to 80 MPH under absolutely ideal conditions, my feeling is that in the real world, the slightest headwind, acceleration to pass, or uphill incline, etc. will result in DoD = off.
And the point in the fuel mileage vs MPH curve where above a certain MPH, under certain specific conditions, DoD will not engage - likely results in a sharp drop in MPG. In fact, it will result in a discontinuity (??) in the curve. Meaning a straight drop, where DoD disengages, then a continuation of the downward sloping curve – at a lower MPG level as speed continues to rise.
For example. One might expect a somewhat linear drop in MPG as speed rises across the range of typical US highway travel. (Yes, I know, not really linear and not over all speed ranges, etc)
But for purposes of illustration here - If I assume that at an absolutely steady speed of 60 MPH, my GXP can achieve 30 MPG, then at 65 it might be capable of 28 and at 70 it might be 26 and at 75 it might be 24 and at 80 it might be 22 and at 85 MPH, 20 MPG.
If DoD is operable up to 70, but will not engage starting at say 73.14159 MPH for instance, the numbers might then look like this:
MPH\MPG
60 – 30 (DoD on)
65 – 28 (DoD on)
70 – 26 (DoD on)
75 – 20 (No DoD - instead of 24)
80 – 18 (No DoD - instead of 22)
I am making these numbers up, but I believe they are in the range of possibility \ reality for my GXP.
This would mean that exceeding the DoD engagement threshold would cost something like an additional 20 or more percent (24 with DoD vs. 20 without DoD at 75 MPH and 22 vs. 18 at 80, etc.) beyond the expected decrease as speed rises beyond whatever that critical speed actually is. My driving suggests that the speed where DoD does not engage in ** my ** typical driving is between 70 and 75.
But that’s just me speculating.
YMMV.
- Ray
Still enjoying the drive – and not obsessing about MPG . . (?)
MPG wise, the ratings on the sticker, like every car, are based on outdated testing....don't get me started. Anyone who considers them gospel in todays world hasn't done much real world research or heard about the testing variance. I suppose it could happen, heck, there are new parents who haven't a clue about peanut allergies either.
DOD does work and I routinely drive 75-80 mph and get 26mpg which is dang good for a V8 powering 3600lbs. 13-15mpg in the city isn't bad either. My GTP average 16-18mpg. Yes, I have a heavy foot.