When you think about weird cars, what do you picture? Perhaps a Citroen 2CV merrily skipping its way across a field, or an Innocenti 950 Spider touring up an Alp. Either way, it’s likely not a full-size front-wheel-drive American sedan with a rental-grade interior. However, there are exceptions to everything, and the Pontiac Grand Prix GXP was completely mad. A W-Body with a V8 made to chase European sports sedans shouldn’t exist, yet you used to be able to walk onto a Pontiac lot and buy one. Crazy, right? If you’re not convinced, just continue reading.
Welcome to weird spec, a recurring series where I go over some of the more mundane oddities of the automotive world. It’s easy to tick off great options on great cars, but those who tick off strange options on normal cars deserve credit too.
Throughout automotive history, there aren’t many cars with transverse V8s between the front tires. Outside of a single generation of Ford Taurus SHO and a handful of Volvos, you’re most likely to find this sort of layout in a GM product.
In the beginning, GM wanted to do something really different with the Oldsmobile Toronado and mated a 425 cubic-inch V8 to a transaxle for secure front-wheel-drive handling. however, despite the Toronado’s front-wheel-drive layout, its engine was still mounted longitudinally (there was a chain-drive involved; it was bizarre). As the years progressed, GM’s rationale for front-wheel-drive V8s was driven less by flagship appeal and more by practical considerations. American luxury car buyers wanted the smooth, effortless torque of a V8 and transverse front-wheel-drive platforms hold weight (and thus fuel economy) and packaging advantages over rear-wheel-drive platforms, so cars like the Cadillac Allante and Oldsmobile Aurora made sense. However, the tides were beginning to shift in the 2000s. Floating along on a two-ton waterbed was out, crisp European-inspired handling was in, and rear-wheel-drive was back. However, while Chrysler was kicking ass with the LX platform, GM looked at its history of transverse V8-engined cars and thought “how hard could it be to make this concept compete with the best sports sedans from Germany?”
Instead of the Northstar, GM ended up almost completely re-engineering its LS V8 to fit in transverse applications. Sure, the cylinder head castings were standard LS6 units, but almost everything else was new. The water pump was remote-mounted on a manifold that featured integrated idler pulleys, the crankshaft was shortened, the starter moved to be mounted on the gearbox, and the entire block was new. Seriously though, take a look at this crazy water pump manifold.
The result was a 5.3-liter V8 that made 303 horsepower, exactly three more than an L37 Northstar from 2004. That’s a lot of work for such a small result up top, but an extra 30 lb.-ft. of torque seems worth the hassle. The LS4 V8 also gained something familiar to Cadillac buyers of old – cylinder deactivation. The LS4 was the first LS-designated performance small-block V8 to feature cylinder deactivation, and GM still hadn’t worked out the kinks more than 20 years after Cadillac’s disastrous attempt at the tech. The LS4 suffered from lifter wear issues, although they typically wouldn’t appear until after another failure point made itself known.
Just like how Porsche had Tiptronic, Pontiac had a paddle-shift function of its own. Named Tap-shift, both the left and right paddles operate in the exact same way – push forward to upshift, pull back to downshift. The problem is, you only really have one upshift and one downshift in spirited driving because first gear goes to 56 mph and second goes to 105 mph. If drag and tires suddenly weren’t concerns, the tire diameter and gearing mean that the Grand Prix GXP’s fourth gear is theoretically good for 235 mph. I’m not making this up, it’s a 0.7:1 fourth gear with a 2.92:1 final drive and a 255/45R18 front tire.
Of course, that’s assuming the gearbox works. While GM had the 4T80-E in its arsenal, the MN7 4T65-E HD was called into duty here. The problem with that is the MN7’s torque capacity of 280 lb.-ft. is a smaller number than the 325 lb.-ft. the LS4 V8 can crank out. Oh dear. Here’s what GM LS4 superfan site LS4 Store has to say about this:
The “HD” stands for Heavy Duty. Otherwise, they’re based on GM’s 4T65E transmissions, but with some beefing up of various components. MN7s come from the factory with upgraded input and final drive sun gears, carrier assemblies, and upgraded drive sprocket thrust washers. Additionally, MN7 have modified cases for relocated starter mounts.4T65E-HD MN7s are rated from the factory at 280 ft-lbs of torque on the engine side, 400 ft-lbs of torque on the gearbox side. However, LS4s come from the factory rated at 325 ft-lbs of torque at the crank. Some have speculated that this may lead to long-term sustainability issues for stock transmissions. Unfortunately, there are hundreds of cases of transmission demise. My stock transmission — even with life-prolonging upgrades — broke down after 45,000 miles.
Still, when the gearbox was working, the Grand Prix GXP could sprint to 60 mph in under six seconds, not blistering by today’s standards but pretty damn quick for the mid-2000s.
So that’s power sorted, what about handling? Well, the problem with front-wheel-drive V8-powered cars is that they’re typically very front-heavy. At the back, you have a muffler, a fuel tank, and the rear suspension, while the front end bears the weight of an engine, a gearbox, axle shafts, suspension, the list goes on. Pontiac’s engineers were targeting BMW with the Grand Prix GXP, which is a bit like if Taco Bell said it was aiming for a Michelin star. I like Taco Bell, but it’s not on that level. Still, that didn’t stop Pontiac engineers from trying something very unusual to band-aid the handling balance.
Up front, the Grand Prix GXP got eight-inch-wide 18-inch wheels wrapped in 245/45R18 tires. Out back, it got seven-inch-wide 18-inch wheels wrapped in 225/50R18 tires. Basically, they looked at a Corvette’s rolling stock and thought “What if we did that in reverse?” A staggered tire setup typically consists of wider tires on the rear axle and narrower tires on the front axle because that promotes safe understeer on rear-wheel-drive platforms. As Pontiac tried out a reverse stagger, it had the reverse effect, neutralizing some understeer on a front-heavy platform.
The subtle lunacy continues inside the Grand Prix GXP, where a giant Campbell’s soup can-sized knob sits just to the right of the gear lever. Does it stiffen up suspension, change drive modes, or even adjust the level of active traction control? No, it controls the heads-up display, with the knob rotating through three levels of brightness. If you actually want to change the information on the HUD, you have to use the little rocker switch on top of the knob, although you don’t get much selection. Page one displays everything, page two displays everything save for compass and outside temperature, and page three turns off the gauge cluster lighting at night so you can just use the HUD. Granted, the HUD isn’t a GXP-exclusive feature, but you definitely won’t find it on a base model.
What you won’t find on any other 2005 Grand Prix is a G-meter. Built into the driver information center at the top of the dashboard, the G-meter displays peak acceleration, deceleration, and lateral g-forces, but only when the vehicle is stopped. What miserable lawyer imposed those conditions? In case you forget that you’re in a Grand Prix GXP, Pontiac gave it special bolstered sport seats and a unique instrument cluster with a font that’s actually legible, turned aluminum accents, and the GXP emblem on the 160 mph speedometer.
Another bit of strangeness worth noting despite being featured on every eighth-generation Grand Prix is the dashboard. Because Pontiac was GM’s excitement brand, the design team figured that the Grand Prix should get a driver-oriented center stack. Common equipment on cars like the BMW E46 3-Series, Oldsmobile Aurora, and Honda S2000, it often helps the driver but leaves the front passenger a little bit bored. The Honda S2000 and E46 3-Series gave their passengers pretty much nothing to play with, while the Aurora upped the ante with climate controls in the door. However, the Grand Prix offered not one, not two, but four air vents exclusively for the front passenger. There’s a well-known joke about how GM designs an air conditioning system and then builds a car around it, and the Grand Prix really seemed to lean into it.
What makes the special V8, the reverse-staggered tires, and the bizarre lawyer-nerfed g-meter even crazier is how ordinary the Grand Prix’s bones are. This thing’s still a W-Body, and it was the darling of rental car lots and company car fleets. The Grand Prix GXP is a bit like if Dodge dropped a V8 into the Stratus, or if Nissan dropped a V8 into the Altima.
The Pontiac Grand Prix GXP wasn’t the only car to get the LS4 engine, but it may have been the weirdest. Sure, the Impala SS was a bit more common and the Buick Lacrosse Super was more of a sleeper, but the glorious lunacy of the Grand Prix GXP is something to celebrate. It’s like a more mediocre version of a Hellcat, a gloriously excessive exercise in making a platform do something it was never meant to accomplish. I bet that Roger Smith never expected this platform to eventually pack more power than the 1987 Corvette, or the reverse stagger, or such ridiculous gearing. The Grand Prix GXP isn’t as good as something like an Infiniti M35 or a Lexus GS430, but it’s a hell of a lot more interesting than either.
Today, you can find Grand Prix GXPs for sale priced mostly between $5,000 and $8,000. That’s not bad value given the insane car market, especially considering what you’re getting. This one’s up for sale in California for a reasonable $5,900 with 138,000 miles on the clock. While sky-high gas prices and the likelihood of some mechanical issues mean a Grand Prix GXP probably isn’t the smartest buy on the market, it’s entertaining as hell. After all, shouldn’t cars be a bit of a laugh?
Oh, and since you made it to the end, I have a little something extra for you. Beneath the GXP in the Grand Prix lineup sat the GTP, a supercharged 3800 V6-powered model that made a great deal more sense than the nutty GXP. To advertise it, Pontiac hired Samuel L. Jackson, and there’s an outtake from his voiceover recording session circulating around the internet. Needless to say, you might not want to play this one out loud at work.
Lead photo credit: Seller
They really should have put the engine in the rear and run a torque tube to the front wheels. It would have made so much more sense in Pontiac land.
Built into the driver information center at the top of the dashboard, the G-meter displays peak acceleration, deceleration, and lateral g-forces, but only when the vehicle is stopped. What miserable lawyer imposed those conditions?
If the internet hasn’t come up with a defeat for this safety check yet, we’re slacking.
The thing I remember most about the Grand Prix is the “W I D E R I S B E T T E R” ad campaign, to wit:
https://youtu.be/RO6U_KawAdg
I did have a Grand Prix rental for a week one time, as a free upgrade (my budget usually limited me to Grand Am-sized cars or smaller). It had the standard 3.8 and I was at high elevations in New Mexico, but in general it was perfectly fine, and honestly my wife and I appreciated the extra room.
The funny thing is I don’t remember anything about the odd mechanicals of the GXP, yet I do remember reading a lot about the Impala SS, which (presumably?) had the same oddities.
That could be, the GP was a year old when the GXP debuted so perhaps a bit less media fanfare, whereas the Impala was redesigned for 2006 with the V8 SS available, so that was more the headliner for the whole model.
I want to say the Impala SS didn’t offer the staggered tire setup, or a manumatic equivalent.
“The Grand Prix GXP is a bit like if Dodge dropped a V8 into the Stratus, or if Nissan dropped a V8 into the Altima.”
Well, Nissan sort of did put a V8 into an Altima
https://www.drive.com.au/news/nissan-altima-v8-supercar-unveiled/
Then you have the Bonneville GXP as well. All of the weirdness of the GP GXP, but saddled with a LESS POWERFUL 4.6L Northstar V8 and the shitty 4T65E, and I’m pretty sure it wasn’t the HD version either. Still to this day I can’t figure out why the larger, heavier car got the lesser engine.
The Bonnie most likely got the Northstar because the work was already done (isn’t it related to the contemporary Cadillac DTS?).
And Seville, before it went RWD in ’04. So yep, it had to have been a pretty easy job. Then after the Bonneville was dropped, the Buick Lucerne debuted for ’06 and offered the Northstar.
Northstar was the ‘premium’ engine—look at the Buick LaCrosse vs Lucerne. The smaller LaCrosse got the FWD LS while the bigger Lucerne had the Northstar.
Let you think too highly is the supercharged 3800, I was the “proud” owner of a beautiful 1999 Buick Regal GS that I picked up for a song around 2003 and kept for 10 years, until I threw a rod ???? There we’re many Achilles heels too this vehicle, the most painful being it only took Super unleaded. Any weekend is Friday was killed by that, the most expensive fuel boat I ever owned, by far. A few more things were that the leather bucket seats looked way more comfortable than they actually were. 6 inch thick seat backs, but only manual rock and no lumbar adjustment? Ouch. Nice looking interior unless you got too close. The dash had three gigantic gauge clusters, but they were mostly filled with idiot lights! I guess Buick forgot who the customer was for the Regal. Blown motor was the last straw and I never even drive it that hard, only used synthetic oils, just didn’t matter. Part of me was sad to see it go, but mostly I was happy as the tire truck took it away.
In my heart I always thought the 2 door Pontiac Grand Prix GT with the 3800 would have been the best configuration, but i have never been willing to give it a try unless it was free…
Sorry, newbie, don’t know how to edit a post here, lots of spellcheck typos – for example, first word is “lest”…
Funnily enough, I did read it as ‘lest’ until I saw your correction
My ex bought a brand new Impala SS and it was a riot, but not particularly amazing. Interior was trash plastics, but the V8 made a glorious noise. GM loves to make (or loved to make now) SS or GXP/GTP/ top end versions of all cars with bespoke or high end engines out of other cars. It’s brand engineering at its best. These were decent cars if you could get the transmissions to last longer than 100k miles.
Now I want to find one of them with a rebuilt transmission and pull the whole engine/transmission thing out and stuff it into a buggy or sandrail or something stupid.
I was thinking a roached Corvair…
Or a Fiero!
To say the LS4 swap in the Fiero is common is an overstatement, but it’s definitely been done numerous times. V8 Archie sells a kit for it!
At least one person has put one in an MR2 Spyder, that car absolutely flies.
All the swaps I’ve seen the 5.3 was ditched in favor of the 6.0 or 6.2… and one complete maniac with the 7.0.
One day I hope to join those nuts.
Let’s not forget the “grown-up” Pontiac across the lot that had the Northstar if the LS4 was too rowdy : the 2005 Bonneville GXP. Although that was on the H-body platform and was meant as a replacement for the SSEi with the L67 that was discontinued after MY 2003.
So if you wanted a V8 Pontiac in 2005, pick your adventure: building a 4T65-HD or bulletproofing a Northstar.
Didn’t the Bonnie also have the NON HD version of the 4T65? If so, not only did it get the shittier engine, but it also got a worse transmission!
No, the Bonneville GXP had the 4T80. IIRC that was the only transmission that came with a Northstar.
You could of course also get a “traditional” Australian-built GTO with an LS2 and RWD in 2005.
Too bad they didn’t bring the Commodore till later. Always liked the shape of the 4-door Holden better.
I bought a 2000 Grand Prix when I got my first “real job” out of college. I traded that in for a 2006 Grand Prix and that bad boy lasted me until 2018 with well over 100,00 miles. I had very few problems with either car and hated that I couldn’t buy another Grand Prix. I know others had issues with them but they treated me very well for 18 years and are a large part of why I’ve only had 4 cars in 30 years of driving.
The LS4 was completely unnecessary in these cars. With FWD, you couldn’t get that much torque into the pavement no matter how hard you feathered it.
A blown 3800 is more than enough to make these Ws pull like a locomotive.
Nifty-ish, but I know the transmissions in these are basically made of glass. Not a matter of if they’ll break, but when.
The supercharged 3800 was maybe more ‘sensible’, but they only put the Series III s/c version in the Grand Prix and not the other final W-bodies for some reason. Could they have stretched the power more? Maybe, but at 260 hp even another few ponies probably wouldn’t be that meaningful when Nissan was getting 255hp in the VQ35 in the ’02 Maxima on regular gas, and 265 in ’04*. (Now look at things with turbos everywhere.) Marketing-wise GM, and the Big 3 in general, were starting to lean heavy on nostalgia and history again, so a V8 made sense and you suddenly had 3 Buicks offering V8s (Lucerne, Rainier, Lacrosse).
Back to the GP GXP more specifically though…I don’t think the Northstar would have been such a simple drop in just because it was a transverse application, or at least it wouldn’t have made any more sense to do so.
– As something of an answer to the Chrysler LX cars (and the marketing of the time), an OHV LS motor made more sense than the DOHC Northstar, marketing-wise.
– The Northstar maxed at 300hp in 2004 – but new SAE ratings knocked it down by 10 hp in ’05. So it did have a bit more of power advantage. (Maybe stranger is that by 2012 they put the 300hp DOHC 3.6 V6 in the W-Body Impala.)
– I’d tend to think that by the mid-00s, any further development for the Northstar wasn’t going toward FWD/transverse applications. Cadillac was revamping the lineup for RWD, and so any new work on the Northstar series was going toward those uses – SRX, STS, etc.
– Not sure if the Northstar would have even fit in the engine bay of the W-body, or would have needed just as many changes; other large(r) GM sedans that did offer the Northstar had that engine planned long before.
– Plus, the Northstar never had cylinder deactivation added in any form (probably to avoid the V8-6-4 comparison), while they were adding that to the LS for other applications and probably needed to do from a competitive standpoint (what with the Hemi having it). Quality-wise, Honda started adding VCM at the same time to their V6 and also had issues, so I don’t think anyone really got it right for a while (have Ford, Mazda etc. on their 3/4 cylinders that drop a cylinder?).
– And TAPshift…it was novel on a 4-speed auto when Chrysler rolled out Autostick ~10 years prior, but by this point everyone was starting to roll out 6-speed autos.
Really, a lot of it is GM working with what they had, but they created more work for themselves more from their own past mistakes or decisions. Imagine if they had brought the Commodore over like they previewed in the Buick XP2000 concept in the 90s?
*Always irked me some that GM ‘performance’ models at this time were often not really better powered than a regular equivalent competitor. The ’06 G6 GTP/Malibu SS had 240 hp from the 3.9L V6, less power than a V6 Altima or Accord at that point.
TL:DR – the Samuel version.
I like this a family hauler and the cost pretty good. I current have my DTS filling that role so cannot justify buying one.
I had 6 years growing up riding around in the back of these Grand Prix’s, not the GXP though. Just seeing a partial interior shot disturbs me to my core, and reminds me why I care so much about look/design, and FEEL of the car interiors I buy now. Man I hated those. After the 3 consecutive 2 year leases of Pontiacs, Dad stepped it up to 6 years of Chevy Impala, with plastic just as bad, and a TPM System that never worked. I thought I was a GM guy growing up, then 12 years in those crappy interiors and I lost all interest in GM.
The Pontiac looked rowdy, and was rowdy. I don’t think that’s so strange. The Buick Lacrosse Super looked like what Meemaw would show up to Sunday dinner in. Then when she left, there would be dust hanging in the air above the dirt road for 5 minutes.
Ford also had a transverse V8 in the ninth generation Lincoln Continental.
IIRC, transverse applications were the original purpose of the 4.6 modular V8, right?
That’s why when they rotated it 90 degrees for use in RWD vehicles like my Mustang, the oil filter is in an obnoxious location!
Literally was looking up late model Grand Prix GXPs as a winter beater. I like used cars deserving of a second chance, especially when a Suburban engine is plopped into a sedan
I am really hung up on the fact that they put a transmission not rated for the output of the engine in these. I’m guessing some GM engineers did poorly on the greater than/less than section of the SAT. 😛
Much more likely is that a beancounter upstairs did all too well on the greater than/less than section.
“The 4T80 costs $X and the 4T65 costs $X-Y, warranty costs per vehicle will be $Z, Z is less than Y, therefore go with the 65”
In my experience, engineers are often all too aware of what will fail before things go into production; the fact that the failures happen has a lot to do with cost requirements imposed from above.
A V6 Grand Prix of this variety was the only car I’ve ever bought new, sight unseen, without so much as a test drive. It was a real impulse buy, but GM was really nearly giving them away on lease in the Detroit area if you had a GM employee in the immediate family. I think they were running a deal for like $149 a month with a small down payment. I had a paid off 7 year old car that was starting to give me troubles. After trade-in, I paid nothing down and I think my lease payment was something like $79 a month after taxes. I figured, for that price, how bad could it be. They didn’t have any on the lot, and I was basically getting one that was on a truck on the way to the dealership. I got it a few days later. It was a fairly ugly car, but it was pretty fast, yet good on gas with the good old GM 3.8L V6 in it, it was comfortable and it handled pretty well for a 4 door sedan. It never gave me any trouble, and I appreciated that cheap lease rate for 3 years.
The Torquesteer Sleeper dream garage:
1998 Taurus SHO
2006 Grand Prix GXP
2008 Impala SS
2005 Altima SE-R
2008 TL Type-S
I hope you save room for a Saab Viggen!
Or even the regular Saab 9-3/9-5 with higher output turbo 4. I found my 2000 9-3 with just the regular 185HP 2L turbo had a decent amount of torque steer.
What about a Mopar entry, a 1992 Dodge Spirit R/T?
Or the Caliber SRT4?! 285/265 hp/tq going through uneven half shafts (even double checked: the left axle shaft is like 60% of the length of the right axle shaft!) with electronic LSD?!
Instead of “drop a gear and disappear”, it’s likely “drop a gear, spin it out!” with a CSRT4.
Ya got me beat, if only b/c the Caliber was so reviled right out of the gate, that edition would in fact be the ultimate sleeper. TBH I didn’t even remember that Dodge offered an SRT version of it, that’s how much I tried to put that car out of mind!
Or the Neon SRT-4
If you want torque-steer: lane changing, heart stopping, pants wetting, terror inducing TORQUE-STEER
You need a humble looking 1984 Dodge Colt GTS Turbo twin stick.
But wear a helmet and diaper when shifting under boost. You will thank me for the recommendation.
Missing the Cobalt SS – came in supercharged or turbo forms
I never drove the supercharged one, but the SS Turbo actually didn’t torque steer all that much. I narrowly missed out on buying one when they were new, and to date it’s still the wildest test drive I’ve been on. Salesman didn’t bat an eye on a full throttle 2nd gear shot through a neighborhood.
I think the supercharged ones were the earlier ones that were a lot more wild handling despite having less power.
*Saab 9-5 Aero careening by in the background*
I’d also add to this list the 1988 Dodge Shelby Charger Turbo – when you dropped the hammer, you’d better be holding on with both hands!
I was thinking Omni GLH Turbo, but I suppose the Charger was just as bad. Point of contention though- the Charger/Turismo bowed out in MY ’87- there was no ’88 Shelby Charger.
Like this very much as a new Autopian series – Torquesteer Tuesdays?
I’ll throw another offbeat choice for the Torquesteer All-Star….Volvo S60 T5, mine was a 2001.
Yeah, objectively this is dumb, but the result of everyone laughing at goofy stuff like this is that we get a sea of anonymous crossovers all sporting the same 2.0Ts.
The late 90s – early 2000s were a refreshing period of “fuck it, let’s give that a shot”, especially from the domestic automakers. So much creativity, and so little of it survived the recession.
Make a retro-styled car and sell it as a tamer cruiser style hot rod? (Prowler, T-bird, SSR) Fuck it, let’s give that a shot.
Make another retro-styled car and enter the small wagon space? (Pt Cruiser, HHR) Fuck it, let’s give that a shot. Why not make a performance version (!!) and a convertible version (!!!!!!!) while we’re at it?
Put a big engine in an anonymous family vehicle? (Ram SRT-10, LS4 triplets, Marauder) Fuck it, let’s give that a shot.
Should all of the above come with rental grade interiors? Of course they should.
These were cool in their own way. I actually knew someone who owned one, he was envious when I bought my G8, but his car actually sounded better in stock form. The LS4 had a nice growl to it.
I really wanted one, but the DOD and teh lack of room in the back seat kind of nixed that idea. still these, the buick and even impala front drive LS cars were more reliable than any Northstar or variant of it, so these make for much better rear drive sports cars swap fodder, and of course just replace the lifters and poof DOD no more.
For some reason, I read DOD as Dept of Defense and was like ‘Why does the gov’t not want this person to not have access to a Pontiac?’
But what did OP actually mean with DOD?
Displacement on Demand. Singlehandedly responsible for all of the systemic camshaft/lifter issues on the newer LS engines.
Hard pass. They were ugly AF.
I will take a Grand Prix GTP 2 door. Put some bolt-ons and smaller pulley and smoke the GXP.