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3.4L DOHC top speed


Guest Anonymous
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odd my 3.1 accelerates in 4th...not sure what speed i'm going (speedo is way off) but i can get to 4th gear and keep accelerating...i'm absolutely, positively, honestly, telling the truth

 

then again my ECM has been tinkered with...not sure if it's the original programming or not

 

 

but now i'm wondering...i'll check maybe monday...not on the road...jsut using jack stands and slowly accelerating just to see where the govrener hits...i know i can't emulate the drag of being on a highway in 4th plus i never drive that fast anyways so why does it matter if it keeps accelerating in 4th on the highway :lol: i like 0-60 speed and sometimes 1/4 mile speed for a road car...now for a race car....well i wouldn't be using a w-body for a race car period :lol:

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If your motor isnt stock, why are you challenging him based on what he said? Think about that.

 

I would demod mine in a heartbeat and run him. Again Im not a 3.4 hater, but I am sick if reading these B.S. stories on here from these kids.

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Ok, well you go ahead and demod your engine then and run the car he doesnt own anymore. Ive been in a stock DOHC auto that had more low end than my 3.1, so a modded DOHC with the right cam timing could pull harder down low than a stock L67 car. Car weight, gearing, torque converter...yeah, more to it than just engine numbers. I really dont care though, i just found it amusing that you wanted to challenge him when you aren't stock and he doesnt own the car anymore.

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I really dont care though, i just found it amusing that you wanted to challenge him when you aren't stock and he doesnt own the car anymore.

 

I find it hilarious that people talk to much shit on here. Hell, I didnt know he didnt have the car anymore!

 

DONT HATE, PARTICIPATE!

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ya i don't own the car anymore. and i think its funny how u can call bs. what did i say that is so unbeliveable? u make it out like a stock l67 will never get beat by a 3.4. i laugh at your insolence.

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I would like to debate the idea that 4th gear will not pull to top speed. I can pull just fine at 80 and running only 2500 RPMs. I would think that when I am running 4500 RPMs I would have much more power to overcome the drag of the car. I haven't had it to insane speeds, but I've had it to 110 and it pulled just fine in 4th with plenty more to go.

 

Ok..........try this.........

 

Look at this dyno chart of a 3.4L DOHC (from a 95 Grand Prix GTP with a K&N drop-in...and a Hypertech chip that as you can see, does NOTHING):

 

hypertech.jpg

 

Now, as you know, at ~130mph the LQ1/4T60-E combo should be sitting around 6000-6200rpm in 3rd gear (NO more than 6400rpm even with a TC that slips more than usual). At that rpm an LQ1 auto makes a little over 160whp (which is MORE than enough to go 130mph, even in a big car like this). Now, shift the car into 4th gear...........it drops to ~4200-4300rpm.............where you have only ~135whp........

 

Now, obviously the BEST you can hope for is to hold 130mph, but with a W-Body's .34 C.D. and larger frontal area, it's VERY likely that 135whp is NOT enough to go that fast .........in comparison, my old SE-R with 134whp went 130mph on the nose (GPS verified) sitting AT it's power peak (5th gear at 130 puts it right on peak power)............and it's a car with similar coefficient of drag (.35), and MUCH smaller frontal area (20.4 sq/ft vs a W-Body's 22.6sq/ft [according to the source I was given]). So........if the car (W-Body) doesn't have enough power to go that fast, it will decelerate (probably to 125ish mph or a touch more).

 

Either way, the car WILL pull further in 3rd gear than it will in 4th. There is just too much of a ratio gap.

 

So. Top speed on an ungoverned LQ1 IS in 3rd gear (with it being stock to having mild bolt-ons and having the stock 3.43 gears)..........probably in the 130-135mph range, with 4th gear only being able to get into the high 120's, MAYBE 130 at best.

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odd my 3.1 accelerates in 4th...not sure what speed i'm going (speedo is way off) but i can get to 4th gear and keep accelerating...i'm absolutely, positively, honestly, telling the truth

 

I'm sure you ARE telling the truth. 3.1L MFI's hit 4th gear at a MUCH lower speed than LQ1's and have a TOTALLY different powercurve. I bet your car WOULD pull to top speed in 4th gear..............at about 120mph at a little under 4000rpm............except for the ~112mph governor that is :D

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I got my 3.1 4 dr Regal to 130 on the speedo once. I was going down a hill and the car wouldn't go any faster.

 

Was it chipped?

 

Then again...........speedometers aren't always the most accurate. My G/F's Neon R/T reads 110mph at an actual 104mph (GPS verified).

 

Here's a video to give you an idea of how bad an average speedometer is: Neon 0-124mph

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It had Ben's old FDP chip in it.

 

Ah..........now THAT makes sense, because even though speedometers in general aren't exactly precision instruments (as you saw from the video I posted), the W-Body's all seem to be fairly decent where accuracy is concerned.

 

And 130mph downhill is doable. My SE-R would barely exceed 130 on flat land, but I had it at an indicated 149mph/7250rpm (~145mph actual) downhill one time (long, STEEP hill :D).

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with a couple of mods you could get the HP to 180 at the wheels. And in addition, my car had enough power going 90 and running 2500 RPMS (75 HP) to pull just fine in 4th. With about twice the HP I'm sure it can pull.

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with a couple of mods you could get the HP to 180 at the wheels. And in addition, my car had enough power going 90 and running 2500 RPMS (75 HP) to pull just fine in 4th. With about twice the HP I'm sure it can pull.

 

But you won't HAVE 180whp at the rpm you need. So it WON'T pull 4th gear.

 

Remember, doubling your speed doesn't double your drag..........it QUADRUPLES it (drag goes up exponentially).........

 

Lets look at your 90mph analogy. First off, at 90mph you should be just shy of 3000rpm (~2900 or so), at which point a 3.4L DOHC auto is making ~95-100whp. You can do this "easily" (it doesn't NEED all 95whp to hold that speed). Now, if you want to go 135mph "easily" (as easy as you can go 90) you'll need 215-225whp (1.5 times the speed.........1.5 * 1.5 = 2.25). Uh oh.............suddenly you can NOT do this "easily" (since the engine doesn't even make that much PEAK power.............let alone at the 4400-4500rpm you will actually be sitting at.

 

In fact, for a car this large and aerodynamic (nearly a 23 sq/ft frontal area and at LEAST .34 C.D. [GFX, even factory ones, often lower this]) it should take roughly 160whp (as the dynojet measures it) to go 135mph. And since in 4th gear at ~4500rpm (~135mph), you are only making 140-145whp..........this means that you will need at LEAST 15 more whp AT 4500rpm to even be able to HOLD that speed. The problem here is that even with intake, UDP, chip and exhaust, you just aren't going to be making the extra required power (at 4500rpm) to do more than *maybe* hold your speed off of the shift. I mean..........a 3.4L DOHC that makes 180whp (quite possible with the above mods) will also make ~180lb/ft in a broad spread.........but even with 180lb/ft @4500rpm, you are only making ~154whp at 4500rpm (do the torque to power conversion)...........

 

Like I said. Even with bolt-ons, a stock geared 3.4L DOHC just isn't going to pull 4th gear. At BEST you will hold you speed off of the shift (with the stock 6500rpm rev limiter in 3rd limiting you from pulling any higher in that gear).

 

 

 

 

If any of you guys (that live semi close to Iowa) want to prove me wrong, I have a handheld GPS and a video camera. That will take ALL of the BS out of the equation.

 

Oh.........and once it's at full health, I WILL be doing (and filming) a top speed run on a chiped 3.4L DOHC 5 speed (91 GP). I'll bet even IT can barely exceed 135mph (with a better geared and more efficient tranny).

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Hey, I'm in Sioux City. Are you going to the Lincoln meet? My analog speedo in my Lumina goes to 115 and the tires are oversized, so I KNOW it's wrong. It would be fun to do a top speed run in the Lumina after I get a chip that works BEN YOU KNOW WHAT I'M TALKING ABOUT.

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I am using my car for an example.

 

I cannot pull a L67 below 3000 rpm. Their blower just gives too much torque. As for high end, I can walk away. The only reason my 1320 isn't a lot better is becuz of my 2.3 60ft. There is a silver one in town with intake, exhaust, and a small pulley. In case you all havn't felt it, a pulley makes those things a whole new car, it is amazing. The thing sounds so good once that blower starts whining. We were side by side up to 120-this was without headers and on my old motor. The 3.8 SC is not the God of V6s, it is way overrated.

 

Bigbulls you must be talking about the autos cuz a 5-speed stock will pull right through 4th. On the way to the track, I redlined my 4th in Kansas and it was still pulling nicely, and this was with exhaust, CAI, chip, UD pulley. No new motor, no headers. Now since I hit my 124mph limiter at about 6400 in 4th, I figure 7000 in 4th is 130. I could have gone to 5th, but I wussed out and my tires are only H rated.

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Bigbulls you must be talking about the autos cuz a 5-speed stock will pull right through 4th. On the way to the track, I redlined my 4th in Kansas and it was still pulling nicely, and this was with exhaust, CAI, chip, UD pulley. No new motor, no headers. Now since I hit my 124mph limiter at about 6400 in 4th, I figure 7000 in 4th is 130. I could have gone to 5th, but I wussed out and my tires are only H rated.

 

Indeed I am.

 

A 5 speed LQ1 should be able to hit ~135mph with 225/60R16 tires at roughly 4600-4650rpm in 5th gear.

 

With 245/50R16's (~3% shorter), I expect 137-138mph at 4900rpm in 5th (the shorter gearing allows you to access a little more of your peak power).

 

This is stock.............

 

I'll verify this once Canada gets my old GP up and running (and we get the title transfer finalised), and then buys himself a chip.

 

I figure with just a chip and the K&N drop-in that is there, 140/5K rpm is NOT out of the question (the car has 245's).

 

 

 

 

I think with your car in current form, 150mph/5300rpm (with 245's) isn't totally out of the question..................145ish is more likely though.........

 

Even the 5 speed's are just geared a little too long to be true top speed cars.

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Guest Anonymous

Anyone know how easy chips and filters are to install? I havent done anything to upgrade my 3.4 yet. The interior and exterior is almost done, now its time for the engine.

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Unfortunately for you, FFP doesn NOT yet offer a chip for 94-95 cars, although I understand Ben/Sappy/Vegeta is (or was) working on one.

 

I WOULD hold out for this, rather than buying a Hypertech, JET, Superchips or Fastchip. The FFP will actually make some power, whereas the others won't.

 

Now the actual install on 91-93 cars is dead easy............I *think* it's the same on 94-95's...........pull of the coolant recovery tank (2 small bolts), loosen the 2 PCM holdown bolts, flip the PCM over and loosen 4 more small bolts on the back holding down the cover for the chip, take said cover off, and pull out chip (it has little tabs on the ends).

 

Easy.

 

 

 

 

 

As for filters...............I would go one of two routes..........either just buy a K&N drop-in and accept the fact it only gives you 1-2hp (but better gas mileage), or design and build a full fenderwell Cold Air Intake (or buy one off of Redz Monte/Mands Production if you can get ahold of them). Also, a small company called Tranzgenic is looking into designing CAI's for W-Body's.............they haven't made any decisions yet, but they DO make pretty nice products for Beretta's and Grand Am's. Either way, don't make a WAI (or just drop a cone on the end of the stock intake pipe)............it positions the filter RIGHT next to the exhaust crossover, and will cause low rpm problems in 1st gear (although you WILL see gains once the car is moving).

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wait...Sappy and Vegeta are the same person...haha...i would have never guessed

 

Yep........he's an asshole all the way around.

 

He DOES design/program some pretty good chips though...........WAY better than what the larger companies can do.

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