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Discussion Starter · #1 · (Edited)
I had been running a 3.4 DOHC 1995 Pontiac Grand Prix GTP for the past 5 years, bone stock except for pulled EGR. Bought the car for $3400 A-title w/102,000 miles, now it has 178,000 miles on it and still runs like a bear. Factory rated 210 HP that year. The cat is still on the car, and the exhaust is OEM from the cat back- original exhaust system from 1995, which is pretty damned amazing considering our environment here (salt, ice, snow, rain)

Last week bought a 2001 Monte Carlo SS 3800 Series II factory rated 200 HP. Previous owner pulled cat and resonator- I pulled EGR. It runs strong at WOT, but it's obvious by gut feeling the old GTP would smoke it in a race.

When the weather breaks, I'm going to get my friend to drive the GTP and we're going to line them up. The obvious reason the 3.4 "feels" stronger would be the bigger cylinder heads and more valves and cams. Out of the hole it DEFINITELY makes more power, a lot more, than the 3800 Series II.

what say you ? all/any opinions welcome. Please don't tell me to plug the EGR back in, both cars are pooches with that thing hooked up.
 

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well if its rated at 10 more hp and its in the older & LIGHTER w body chassis it makes sense I guess

time for a top swap on the 3800
 

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yeah i was thinkin the same thing a while ago. I also had a 95 red GTP with every option i miss that car! I know it would waste my 02 grand prix but im hoping that will change once i get a intense pcm :icon_twis
 

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Discussion Starter · #4 ·
well if its rated at 10 more hp and its in the older & LIGHTER w body chassis it makes sense I guess-time for a top swap on the 3800

3.4 DOHC is twice the motor the 3800 is- 3.4 made 281HP on factory dyno, was detuned w/spark/fuel maps to make tranny live. 3.4 is easily 80 HP stronger in stock form, if remapped back to the original specs.

I drove a 3.4 for 5 years, it would chew up this 3800 and spit it out- both cars weigh the same

see it here

THE 3.4 DOHC 24 VALVE

3.4L DOHC 24-VALVE GM V-6
This is page is brought to you by JJ and hosted by Steve. We will start by saying that we are not the foremost authorities on the 3.4L Twin Cam V-6. But JJ however has collected a pile of info on this engine. From the owners standpoint, a GM autotech, and weekend racer. If anyone who may read these notes has something to add, or even correct, it would be appreciated. Sharing info amongst us 3.4L DOHC owners is going to only help us all. The reason JJ wrote this and I host this site.

The 3.4 was concepted as a V6 version of the Olds 2.3L "quad 4". The quad motor went into production in 1988, and that also marked the start of the V6 design program. The 3.4L DOHC was actually the forerunner of many current motors. The Cadillac Northstar 4.6L 32 Valve V8, and later the Aroura 4.0L 32-Valve V8, were sons of the V6 program. Now we have expanded into the 3.5L V6 and to a degree, the OHC Truck V8 small-block. Most of us wouldnt put that as important, but the lessons learned on the Quad 4 went into improvements for the 3.4 V6, and subsequently, the Northstar and Aroura.

The 3.4L DOHC motor was designed with a CHEVY name, and was slated to go into the W-10 body cars, namely the Lumina, Grand Prix, and Cutlass. Buick opted to go with their 3800 Series I V6. Target date was 91 model year, as Lumina Z34's, Grand Prix GTP's, and Cutlass Supreme Internationals. In that order. A funny thing happened on the way to the assembly line....When it was orginally concepted , the little Quad was pushing almost 200hp on 4 Jugs. So the V6 needed to have some more power. Now GM at that time was not know for a good FWD Transmission. Even the rocket 180 HP quads in N-body cars came with 5spds only. No auto was offered as HI-PERF, quite frankly because they wouldnt live behind the motor (remember we have to warranty the car if it breaks). Well, the GM engine gurus went to their counterparts at GM Hydramatic, with a challenge. Build a FWD auto trans, that will take 275 HP. You have 2 years to be in production. In a car. Warranty and all. Hydramatic said, "no problem". Meanwhile, the 2.8L V6 had grown to a 3.1L and was currently in use in the W-10 cars. The 3.1L was redesigned as an overstroke version using a cast iron block. To this went the best that GM had to offer, remember we're building a 275HP FWD muscle car. Forged crankshaft, forged rods, forged pistons, balanced lower end. Revamped oiling system with high volume pump. An oil cooler. On top, a pair of computer designed 4 valve per chamber aluminum heads, with hemispherical combustion chambers. Cross-Flow intake and exhaust ports, designed for maximum flow at high RPM. Next, add FOUR, count 'em FOUR camshafts, each controlling 6 sodium-filled lightweight valves. Dual dampner springs rest under a "bucket"type cam lifters, for instant and precise valve timing. The cams were supported by 4 journals each, providing durability along with the least amount of valvetrain mass. The cams were driven by a cogged belt, further reducing mechanical drag of the motor. The exhaust was cast iron manifolds, large by any standards, with a single high flow catalytic converter using 3inch downpipes. All 3.4L cars used a dual muffler system, which not by coincidence, is mathematically perferct in diameter and distance for performance applications. The intake was a tuned tunnel ram, with the early builds using NO mass air flow sensor, and 94 and later ones using one. Add to this combination Fuel injection, digital EGR, and it was by far, the BEST motor that GM engineers could build for its application. Emission certification verifed an honest 281HP on the sheets. Emission 7000RPM screamer. This was in early 1990, January I believe. Transmission? Anyone? Hydramatic had its own challenges to conquer. The THM125 3 speed was being redesigned every year, to combat the next weakest link in the unit. The THM 440T-4 four speed auto debuted a few years earlier, but was prone to valve body and erratic shifting problems. The 440T-4 also had this quirk of self-destructing if the owner happend to get stuck in snow. Not much to build from...Hydramatic had its hands full on this job. An all new FWD O/D trans was needed. Many prototypes were tested at GM proving grounds, in believe it or not, a V8 FWD Camaro. Each version had uncovered problems, aka "The next weakest link". Time was fast running out. When it came clear that the all-new trans wouldn't be ready for production by mid-1990, there was only one thing to do. Redesign the 440-T4 as best as they could. Hydramatic went to the market with their finished product just days before the deadline. Will it take 275HP? NO! Will it take 250HP? NO! How bout 225Hp? Maybe. GM engine ground was peeved! All this effort, just to be cut down at the flywheel....225HP? I want 275! Well, the rest is corporate decision making at its worst. Cut the horsepower of the 3.4L to 200 with an automatic. You can have 210 on a stick. Makes a guy want to cry, don't it? Well, warranty concerns led the list of "why" and there's no way around it. The redesigned THM 440-T4 was designated the THM 4T60E, with an early RPO code of MXO. Internals were beefed up, a heavier drive chai, a better pump, and best of all, Electronic shifting! Now, instead of finicky hydraulic valve body, all shifts and timing ere controlled by the ECM. The same one used by the motor. Big, beefy driveshafts were installed into the W cars to take the power. (on a side note, I have never heard of one breaking) By this time, tooling up was underway for the '91 model year. While there were a supply of motors, the trans were still being built a few at a time. Delco electrionics solved the horsepower problem by cutting the fuel delivery and spark advance curves of the motor. This weakened it to a 6250 shift point, and 6500 rev limiter. Free-reving was limited at 3000RPM. The first 3.4L DOHC engines were spoken for by CHEVY. After all, it was their project. Stick models didnt get orders, as most dealers preferred the auto trans models because of sales. Add to the problem, af HEFTY price tag on the motor combination, adn they were a tough sell as lot inventory at the dealers. The trans shortage had eased by Feb. of '91, and finally some units were released to Pontiac for production. These facts conclude that '91 models are scarce, some Z-34's, a lot less GP's, and virtually no Cutlass. 1992 was a carryover year for the 3.4L option. Pontiac changed wheel cap centes. This was the only visual change from the '91 cars, save the VIN of cours.

The engine used a speed-density program for the ECM/fuel injection. This consisted of a MAP sensor, a BARO sensor, ambient air sensor, throttleposition ensor, and of course RPM. Cubic inch displacement X rpm, barometric pressure, and air tempurature divided by the throttleposition and engine vacum (load). Witout fail, the computer (ECM) will deliver the same amount of fuel for a given set of input parameters from the sensors. There is no substitute. Spark timing was calculated the same way (an algorithm) based on sensor input. This is very handy to understand when you want to modify your DOHC to do more. The 3.4L works on a multiport injector arrangement. Early year 3.4's did not have a cam sensor in the front valve cover. These are MFI cars. The injectors are fired three at a time, with the logic that one of the intake valves will be open. The other two will puddle the fuel on top of the valve until opens. Starting in 1994, most 3.4's went to SFI. This reduced emissions and allowed for even learn injector rates, atmoization was improved. SFI bascially means that the charge of fuel is fired at an OPENING intake valve, so that air flow will charge the fuel as a vaport. SFI cars are a little touchier to injector rates then MFI cars. The distributorless ignition system firs added/waste spart method. It would take a volume of reference to cover it fully, but just know that it is operated from input from the crank and cam sensors. Picture two companion cylinders (one coil pair) spark leaves the coil on one tower towards the weak cylinder, (the one on the exhaust stroke). The spark jumps the plug gap from center to ground and then travels through the engine block ot its companion, (which is on the power stroke) and jumps the plug gap from ground electrode to center electrode, then back to the coil tower, completing the circuit. A big circle. It reverses every crank revolution too. Spark timing is controlled by the ECM, whcih calculates which coil pair to fire, and how much timing advance or retard is needed at the moment. The intake manifold shape changed every year after 1992. Why the different manifolds? The early ones howled at 2100 RPM in drive, the later ones changed for size constraints in the car, and there was the switch to the Mass Air Flow system, whcih added another variant. All will bolt to the lower intake, but not all will accept the other various equipment needed. Exhaust manifolds are pretty good for cast units. I cant even imaging fitting headers to this beast, but you dont need to. I have run backpressure gauage on my car, and found no significant problem save the converter itself. Al converters are restricitive, but the exhaust is low on the list of places to get more zip from a 3.4. And now that the background is covered, its time you get teh mechanicals of the DOHC 3.4L "Hemi" Hope your not too bored yet.
 

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Discussion Starter · #5 · (Edited)
yeah i was thinkin the same thing a while ago. I also had a 95 red GTP with every option i miss that car! I know it would waste my 02 grand prix but im hoping that will change once i get a intense pcm :icon_twis


now that's funny and interesting, there was a GTP 2-door for sale at a local car lot w/3800, I think it was a 2002- my 10 year old son and I took it for a test ride, I held it to the boards and went through the gears, and remember thinking "it this thing going to go?" My son said "daddy this doesn't go as fast as our old car". No kidding, even he noticed ! I was going to buy the car anyway, but then my wife looked at it and noticed little hail dents in the hood and roof, that I had not seen before. So we passed on it.

I was going to sell my GTP to a local garage mechanic kid for $600, after I bought this Monte, I called him back on Monday told him I changed my mind. I very well may sell the Monte SS. The best way to run this 3800 is in the 1997-2002 GTP w/supercharger. Then it would be stronger than the old GTP.

The Monte is nice though, more options, nicer interior. The GTP is getting long in the tooth from age, and little stuff is starting to break. The CD player doesn't work, never did. The hood latch cable broke, and the glove box door latch just broke last week. The center console door hinge also was broken since I got it, the Monte has a steel hinge to they fixed that problem. Most likely I'll keep the Monte as my "grown up" car, to drive the wife/kid around.

And the GTP to abuse at WOT. This spring I'd like to saw the exhaust off before the cat, lighten the car as much as possible, and take it to the track and get a timeslip on it.
 

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now that's funny and interesting, there was a GTP 2-door for sale at a local car lot w/3800, I think it was a 2002- my 10 year old son and I took it for a test ride, I held it to the boards and went through the gears, and remember thinking "it this thing going to go?" My son said "daddy this doesn't go as fast as our old car". No kidding, even he noticed !
I was going to sell my GTP to a local garage mechanic kid for $600, after I bought this Monte, I called him back on Monday told him I changed my mind. I very well may sell the Monte SS. The best way to run this 3800 is in the 1997-2002 GTP w/supercharger. Then it would be stronger than the old GTP.
Are you comparing an LQ1 to an L36 or an L67. The 02 GTP your referring to is an L67. L67's were also detuned from the factory to stay out of the Firebirds performance Rhelm.
 

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Discussion Starter · #8 ·

good link- the 1996 was the last/best 3.4 DOHC- with improved top end and cams

see link below

GM 60-Degree V6 engine - Wikipedia, the free encyclopedia

[edit] LQ1
The LQ1 (also called the Twin Dual Cam or TDC) was a 3.4 L DOHC V6 motor ("X-code") based on the aluminum headed second generation of GM's 60° engine line, sharing a similar block with its pushrod cousins, the 3.1 L LH0 V6 and the then recently retired 2.8 L LB6 V6. The motor was built only for front wheel drive applications, and was featured exclusively in the first generation of GM's W-body platform.

It was built from 1991 to 1997. From 1991 to 1993, it used tuned multi-port fuel injection, made 200-210 HP (150-160 kW) @ 5200 RPM and 215 ft·lbf (290 Nm) of torque @ 4000 RPM. From 1994 to 1997, it used sequential port fuel injection, making 215 hp (160 kW) @ 5200 rpm and 225 ft·lbf (300 Nm) of torque @ 4000 rpm. It had four large valves per cylinder. The 3.4 L engine used a cogged belt to drive the four overhead camshafts. Adapting a pushrod block for the LQ1's overhead cams was difficult, and the 60° angle made this a very tall engine, but power output was impressive.

Bore was increased to 92 mm, but the 3.1 L engine's 84 mm stroke was retained. There are only a few interchangeable parts between this DOHC engine and other members of the 60° family, namely the connecting rods and crankshaft.

The heads and intake manifolds were redesigned for the 1996 model year, incorporating a larger throttle body and plenum area, slightly shorter intake runners, cloverleaf combustion chambers, and larger "pill"-shaped exhaust ports. Camshafts and cam timing were also revised for the new, higher RPM powerband.

Optional from 1991 to 1993 was a Getrag 284 5-speed manual transaxle, which was also exclusive to the GM W platform and was available only with the LQ1. The electronically controlled Hydramatic 4T60-E 4-speed automatic transaxle was the alternative, used during the entire production run.

Applications:

1991-1994 Chevrolet Lumina Z34 and the Euro 3.4 sedan
1991-1995 Oldsmobile Cutlass Supreme
1991-1996 Pontiac Grand Prix
1995-1997 Chevrolet Monte Carlo Z34
1995-1997 Chevrolet Lumina LS
1997 Chevrolet Lumina LTZ
 

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Discussion Starter · #9 ·
Are you comparing an LQ1 to an L36 or an L67. The 02 GTP your referring to is an L67. L67's were also detuned from the factory to stay out of the Firebirds performance Rhelm.

to restate:

The Grand Prix GT I test drove had the 3800 series II
My "old" Grand Prix is a 1995 3.4 DOHC 210 HP
My "new" Monte SS is a 2001 3800 Series II 200 HP

the only performance mod, if you can even call it that, done to the 3.4 DOHC was unplug the EGR valve- that really woke it up. The car has a catalytic converter on it, with factory exhaust pipe/mufflers from cat to tailpipes outlets. That 3.4 rips and would smoke either of the 3800 series II's I drove.

now let me take this riddle and wrap it in an enigma:

my mom who is 73 years old, has a 1988 Olds Cutlass Ciera 4-door, with 3.8 liter V-6 FWD. THAT engine has BALLS ! When I drive that Olds, the front stands up and transfers weight to the back like an old musclecar on launch- and it still has cat converter and EGR connected. It would smoke all of the above out of the hole to the 1/8 mile mark- after that the newer cars would catch and pass it by the 1/4 mile mark.
 

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Discussion Starter · #11 · (Edited)
How many 60 degree V6's have ran 8s? That's what I thought....

who cares ? you're comparing apples to oranges- if you're talking a tricked out 3800, put the same mods on the 3.4, as that 8-second 3800, and find out

you can NOS-turbo-supercharge any engine, and turn a low e.t.- that doesn't mean it's a good engine design- that means it ran a number, one time- it could very well be the biggest POS on the face of the earth-

i.e., an e.t. slip does not a good engine design make

the 3.4 platform as sold stock from GM, has a better top end than the 3800, bigger heads, more cams, more valves, no pushrods, better exhaust manifolds, sodium filled valves, forged bottom end

for that matter, how many 3800's make 500 HP on the motor with no power adders and 9:1 CR on pump gas, like my old Pontiac 455 does ?

see, your statement doesn't hold any water, it's a moot point...anyone can say that about another souped up engine- we're talking stock engines here, that's the common denominator

the issue is, GM had a better naturally aspirated motor with the 3.4 DOHC, than the 3800 series II- they went to a new motor that makes 15HP less in stock form

just doesn't make sense- my only guess is, later in time emission and cafe mileage standards were more strict on the 3800, than the older 3.4- so compromises had to be made. When an engine that's .4 liter smaller and older makes 15HP more power than a new engine, one would wonder why.

 

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who cares ? you're comparing apples to oranges- if you're talking a tricked out 3800, put the same mods on the 3.4, as that 8-second 3800, and find out

you can NOS-turbo-supercharge any engine, and turn a low e.t.- that doesn't mean it's a good engine design- that means it ran a number, one time- it could very well be the biggest POS on the face of the earth-

i.e., an e.t. slip does not a good engine design make

the 3.4 platform as sold stock from GM, has a better top end than the 3800, bigger heads, more cams, more valves, no pushrods, better exhaust manifolds, sodium filled valves, forged bottom end

for that matter, how many 3800's make 500 HP on the motor with no power adders and 9:1 CR on pump gas, like my old Pontiac 455 does ?

see, your statement doesn't hold any water, it's a moot point...anyone can say that about another souped up engine- we're talking stock engines here, that's the common denominator

the issue is, GM had a better naturally aspirated motor with the 3.4 DOHC, than the 3800 series II- they went to a new motor that makes 15HP less in stock form

just doesn't make sense- my only guess is, later in time emission and cafe mileage standards were more strict on the 3800, than the older 3.4- so compromises had to be made. When an engine that's .4 liter smaller and older makes 15HP more power than a new engine, one would wonder why.

This is one of the most ridiculous threads I've seen yet. You ask how many 3800's make 500HP All Motor with no power adders like your 455 does, now who's comparing apples to oranges? If the LQ1 was such a good engine, then why did they replace it? Please don't answer with emission's standard's as DOHC set-ups are indeed more efficient. Have you ever worked on one of these LQ1's? Any Technician will tell you that the 3800 is a dream to work on. The DOHC 3.4 has cost many a tech their sanity. Also look at what's available aftermarket wise for each of the platforms and how much it costs to perform work on them. Mike at Milzy Motrsports (which is one of the few suppliers of aftermarket parts for the LQ1 will tell you) as he apparently tells Fiero guys not to bother and go with the L36 or L67 due to more solid construction, ease of ability to service, and power potential. Have you seen how many times the 3800 has made the Ward's 10 Best List? As for the Buick 231 which you are referring to as an "new" engine you might want to take a look at the thread below.

Buick V6 engine - Wikipedia, the free encyclopedia

Question: What did you expect by creating a thread such as this? There are so many members here who are watching these threads and posts that your making and cringing, just trying their hardest not to get involved. This is 3800PRO.com. Not 3400.com I have to admit I am trying to be civil here but maybe it's time to find a different forum as you are not exactly making allies here. Not by the questions you are asking ( I will admit that any DOHC set-ups are a good idea) but instead by the manner in which you are making these statements. Have you tried the Grand National forums yet? Maybe your post would get a better answer over there as they upgrade to Series II's often or for that matter the Fierro forums as owners often contemplate for two-seconds on which of these powerplants to go with?
 

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Well to get back on topic how many 8 second cars have over 100k miles on them?? Come on get real this started out simply stating the old DOHC GTP feels faster than the new N/A Grand Prix. Yes comparing an old GTP with the DOHC 3.4 and the new GTP's with the supercharged L67 is way differnet. Thats a new topic for a new thread, but whos the tard that said "How many v-6's run 8's " You my friend need to stay in the context of the tread. :icon_lol:
 

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Okay. As far as the LQ1's concerned the performance was indeed pretty good. It is interesting that GM went a different route with this one by investing in newer technology. The numbers were comparable between the two with the LQ1 at a 10hp advantage as well as a 5ftlb. torque advantage. I think that the main reason that many feel as though this car has a faster take-off is because it does. The torque numbers for the LQ1 were achieved at a lower rpm (4000) rather the higher L36 torque curve. So with that said this is probably why as well as the weight difference.

Now why was it discontinued? It seems (courtesy of GM Inside News and GM TSB's) that both GM and it's customer's were not very receptive to the engine's ideals.

Major customer complaints were the powerband and how quick the car would top-out at higher speeds despite it's quick takeoff. Customers apparently also had issues with spending the money needed for added maintenance, higher cost of general maintenance, as well as reliability issues. The engine suffered from Head Gasket problems as one dealership reported 49 headgasket replacements in one month. We all know un-simmilar metals have different expansion rates. The engine was also notorious for hot-spots especially in since the water-jackets were smaller on one bank. Customers Also did not like the idea of purchasing an interference engine that utilized a timing belt.

GM had it's own issues with the powerplant at the time in realization of it's build quality. GM also did not like the idea that it had to invest more money in a design that the company could not get good build quality out of. (see wikicars -Monte Carlo-Fifth Gen)

Therefore GM turned to the 3800. They found that they could produce a much more reliable with even better than they expected ( see Ward's Top Ten) build quality when they went back with solid Cast-Iron construction. On top of that the 3.8 was cheaper to build. Customer's were happy with it's quieter operation and it's better everyday powerband as well as the engine's reliablity and maintenance costs.
 

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Well I see you guys missed my point in all this. My point was that the 3800 as a whole is a much STRONGER engine with alot less issues across the board than the 60 degree GM V6 motors.

Yes there is the issue with the valve cover gaskets on both variations of the motor along with the upper intake situation on the NA version, which has been fixed on the L26 version. But I feel that pales in comparison to the huge issue of Lower intake and head gasket problems on your ever loved 60 degree V6 motors.

No, you don't see any 100K mile 8 sec GP's, but you do see a fair amount of 12 and 13 second cars that run well over 100K, you just do not see that with the 60 degree crowd.

I for one back when I had an NA motor in my GP had no problems with the power of the motor, it was rather stout and I never had an issue with spanking a few guys with Monte's, Cavaliers, or pre gen GP's. Though I know I had a strong motor, and I can't say how strong or weak those motors were.


You listed off all those "great things" about the 3.4, of which that brings me back to my original point, how many of those can withstand an 8 second pass? ZZP's car ran 8's on a stock bottom end and made multiple passes like that. I know damn well that the 3.4 could not stand up to those duties considered if the "same modifications were taken". Honostly if you look at what got changed on that motor, it's really not that great of a list if you consider what it takes to do that on other motors.

But its all a moot point, I love my 3800's and will defend them, you seem to have a rather blatent bias against them and towards the 60 degree motors. I think you might be a bit more welcome, especially considering your inclinations toward those motors on sites that taylor themselves to the 60 degree V6 world.
 

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I ran 11's with a 101,000 miles on the clock. I plan on running 10's with the addition of a cam and large amounts of nitrous. If i was scared my motor couldn't handle it i wouldn't do it. I'm confident my iron monster is up for the task. DBTK has 240,000+ miles on his bottom end and he's running 11's with over 400whp. Sounds like the 3800 is weak.. :icon_roll I've melted 2 plugs in the same cylinder, and one in another and she just asks for more. Still my daily driver and I'm still kicking the **** out of it. I haven't owned a car yet that i would feel is anywhere near as reliable as the 3800.
 
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