Let's discuss the 4.5L

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locrwln1

locrwln1

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Ok, this is something that I have been thinking about for a long time and I haven't seen a thread that deals with it, so here it goes. By the way this is in no means being done as a slam or anything like that and I'm not looking for the "yeah but it will last 300k miles" answers.

The 4.5l in the FZJ's, the burning questions are why is it not more powerful and if can't/couldn't be made more powerful, why does it get such poor mileage. Lets discuss.

The intake seems to be designed very well, large airfilter, decent size intake, intake runners, cross-flow hemispherical head, valves seem to be of a decent size, double over-head cam, hi-flow exhaust manifolds. All of these things point to a horsepower motor and it would seem as if it breathes well or should.

Inline six of decent size, don't remember compression numbers, longer stroke than bore...correct? Points to a torque motor.

Robust design, lots of oil capacity and all of the other stuff to make it last forever.

Ok so it's bolted to an automatic overdrive, full-time 4wd system in a aerodynamic brick.

Stock power: 212 hp/275lb/ft of torque. Not sure of the rpms of those numbers.

Stock weight: 5000lbs(?) give or take a little.

EPA MPG rating: 13 city, 15 highway.

Now let's compare some apples and oranges.

I drive a '06 Chevy Trailblazer weekdays as my company car (this is not a bash chevy thread).

4.2l double overhead cam, inline six motor, does have variable valve timing, not sure on the hemispherical head or cross flow head design. Don't know the exact specs on bore and stroke or compression numbers.

It's bolted to an automatic overdrive, part-time, but always turning the front axle components, in a slightly less aerodynamic brick.

Stock power: 275 hp-not sure at what rpm/275 lb/ft of torque @ 3600 rpm's, "flat torque curve", quoted from Car and Driver.

Stock weight: 4500-5300lbs.

EPA MPG rating: 16 city, 22 highway. I average around 20-21 mpg driving mixed city and highway 50 miles one way. It will get up and go when asked and very smooth to 6k rpm's, which it sees everyday.


2007 Cadillac Escalade:

Weight similar, aerodynamics similar, full-time 4wd/AWD, 6.2L V8, bolted to a six speed automatic.

Stock power: 403 hp @ 5700 rpm/417 lb/ft torque @ 4300 rpm.

Car and Driver observed MPG, driving the wheels off of it: 12 mpg.

So the question I am asking is: What is the limit when someone asks about making power out of the 4.5l LC motor, that there isn't much power to be found w/out forced induction. What is the limiting factor. Let's use the Chevy 4.2, pretty close except for variable valve timing and it's getting better mileage and more horsepower. What makes it so?

Again I am asking this out of curiosity as a try and figure out where the design limit is.

What is Chevy's secret?

Why does the Toy motor take forced induction to make the power and why does it respond so well?

Why doesnt' it make more power?

If it makes this power, why doesn't it get better mileage?

:confused:

Jack
 
The simple answer is that the LandCruiser's powertrain design focused on durability and longevity. The engine is not in a high state of tune because Toyota wanted it to be a low stressed engine that will run on all manner of marginal fuel quality any where in the world. It responds well (and reliably) to forced induction because the design leaves a lot of potential power on the table that the forced induction picks up. It's known as having lots of headroom - or development potential in the power train world.

If you want an engine to put out a lot of power and it's vehicle to go fast, you start reducing the weight of rotating parts, thin out the block, maximize and minimize things throughout and in doing so give up longevity. That's the Reader's Digest.

As for comparisons to other rigs, you're comparing recently developed vehicles with economy minded powertrains to an ancient overbuilt truck. Simply not a fair comparison.

DougM
 
How about comparing similar SUVs from the same era? Say, a '96 Chevy Tahoe/ '96 Expedition...how did those vehicles compare to a '96 FZJ80? Comparing a '06 or a '07 anything to a '9x doesn't seem fair.

Edit: answered my own question!

From http://www.fueleconomy.gov/feg/findacar.htm

1996 Tahoe 5.7L 4wd mpg 13/17
1996 Bronco: 4.9L 4wd mpg 13/17 | 5.8L 4wd mpg 12/16

1996 Explorer 4.9L auto 4wd mpg 14/18
1996 Range Rover 4.6L full time 4wd auto mpg 12/16
1996 Discovery 4.0L full time 4wd auto mpg 14/16
 
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I had an old Ford Fiesta when I was in high school that had a Ford 4 cylinder tractor motor with a 5 speed in it. That car flew and surprised many a people. I out ran a trooper in it ...I pulled the old clover leaf trick on him.
 
IdahoDoug said:
The simple answer is that the LandCruiser's powertrain design focused on durability and longevity. The engine is not in a high state of tune because Toyota wanted it to be a low stressed engine that will run on all manner of marginal fuel quality any where in the world. It responds well (and reliably) to forced induction because the design leaves a lot of potential power on the table that the forced induction picks up. It's known as having lots of headroom - or development potential in the power train world.

If you want an engine to put out a lot of power and it's vehicle to go fast, you start reducing the weight of rotating parts, thin out the block, maximize and minimize things throughout and in doing so give up longevity. That's the Reader's Digest.

As for comparisons to other rigs, you're comparing recently developed vehicles with economy minded powertrains to an ancient overbuilt truck. Simply not a fair comparison.

DougM
Click to expand...

Doug I agree with most of what you are saying, but probably the biggest issue is why can't someone build the 4.5l up to make more power normally aspirated? What is the design limit? You spoke of lightened engine parts, etc. and how there is so much "headroom" left in the engine, what does it take to find it w/out using forced induction? All of this is hypothetical, and I am in no way looking to build a racecar, I am just curious as to why the 4.5L loves gas. If it can't be built for more power, why can't it get better mileage?

By the same token and for the naysayers about comparing the older truck to newer trucks, here's is another example...

My father-in-law has a '93 Surburban, specs:

5.7L V8, 4speed auto, 4wd. 175K+ miles, original engine. We are talking about the TBI 350. So 210 hp and 315lb/ft of torque (roughly, may be off on the torque). For all intents and purposes as close to an 80 as far as weight, aerodynamics, power, transmissions, etc. He averages around 18 mpg on the highway with it at 75mph. So he's got roughly the same power, but is getting noticeably better MPG. Why? And remember we are talking about a SBC (designed in the 50's and absolutely no high tech stuff anywhere on it).

Again, why does the 4.5L use so much gas to make the power it does?

Jack
 
locrwln1 said:
Doug I agree with most of what you are saying, but probably the biggest issue is why can't someone build the 4.5l up to make more power normally aspirated? What is the design limit? You spoke of lightened engine parts, etc. and how there is so much "headroom" left in the engine, what does it take to find it w/out using forced induction? All of this is hypothetical, and I am in no way looking to build a racecar, I am just curious as to why the 4.5L loves gas. If it can't be built for more power, why can't it get better mileage?

By the same token and for the naysayers about comparing the older truck to newer trucks, here's is another example...

My father-in-law has a '93 Surburban, specs:

5.7L V8, 4speed auto, 4wd. 175K+ miles, original engine. We are talking about the TBI 350. So 210 hp and 315lb/ft of torque (roughly, may be off on the torque). For all intents and purposes as close to an 80 as far as weight, aerodynamics, power, transmissions, etc. He averages around 18 mpg on the highway with it at 75mph. So he's got roughly the same power, but is getting noticeably better MPG. Why? And remember we are talking about a SBC (designed in the 50's and absolutely no high tech stuff anywhere on it).

Again, why does the 4.5L use so much gas to make the power it does?

Jack
Click to expand...
I'd be interested in seeing those MPG calculations after a 75mph trip in the Suburban.
 
So that alkaline kid, He is pretty bright.
the a440 and 442v transmissions in the 80 series are extremely overbuilt, hence the very limited number af failures you see even in a technically anally retentive and very abusive atmosphere.
There is a trade off thought, Look at the suburban mentioned above, if it is a 93 it should have the 700r4 or 4l60e transmission, These are not expected to last past 150k.
I like the point you are making but I think you are missing a point here. The point Doug was trying to make is there is lots of room to make more power on the INTERNALS of the 1fze block. If you were to put 15 psi of boost on to the same 350 in the suburban I would not give .02 for the lifespan of the motors, the internals will not support it.
The 80 is overbuilt, overly safe and not pushing any real boundaries as far as engineering, The gm 4.2 litre you have in your trailblazer was introduced in 02 and took chev two more years to get it dialed in right.
Dave
 
:popcorn:
 
locrwln1 said:
That is the mpg at 75mph:crybaby:

Jack
Click to expand...

PHAEDRUS said:
So that alkaline kid, He is pretty bright.
the a440 and 442v transmissions in the 80 series are extremely overbuilt, hence the very limited number af failures you see even in a technically anally retentive and very abusive atmosphere.
There is a trade off thought, Look at the suburban mentioned above, if it is a 93 it should have the 700r4 or 4l60e transmission, These are not expected to last past 150k.
I like the point you are making but I think you are missing a point here. The point Doug was trying to make is there is lots of room to make more power on the INTERNALS of the 1fze block. If you were to put 15 psi of boost on to the same 350 in the suburban I would not give .02 for the lifespan of the motors, the internals will not support it.
The 80 is overbuilt, overly safe and not pushing any real boundaries as far as engineering, The gm 4.2 litre you have in your trailblazer was introduced in 02 and took chev two more years to get it dialed in right.
Dave
Click to expand...

Ahhh, but you are missing my point. Doug is saying that there is lots of room for improvement, yet no one, that I know of, including Robbie has found it, without resorting to forced induction. He has done some amazing work with his, but "lots" I'm not so sure about.

Second, I don't know of anyone putting 15lbs of boost into the 1fze. The s/c and turbos seem to be around 7lbs. And yes a SBC can take 7lbs.

I am in agreement about the overbuilt part, excluding the HG, which I had to replace in mine. Again this isn't about which is built better, dialed in, etc...My question still stands. If a Suburban of the same era is making similiar power with a bigger, low tech motor, why is it getting at minimum 2mpg better on the highway according to EPA or more in the real world?

I seriously want to know. What makes it so? What is the design limit on the 1fze?

Jack
 
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I'll also cast doubt on a Suburban of that era getting 18mpg at 75. I'll also point out that Suburbans were available with a variety of different final drive ratios and that can make significant difference at fwy speeds.

There are a raft of decisions to be made that can improve fuel economy at every stage of a vehicle's design. Fuel economy is a goal in and of itself, and the 80 was not designed for the US market with its vast network of freeways and daily commutes the rest of the world considers absurd. Its drivetrain is a pile of overbuilt gears that are heavy and have tremendous spin losses. Its shape favors function over wind resistance. The engine had more torque just off idle than the same year's Land Rover V8 had at its peak. The engine's fuel system runs rich because this reduces damage potential under stress. The vehicle is full time 4WD. All manner of these types of decisions were made to produce a vehicle optimal for a rough life in adverse conditions, but one ill suited for suburban American life.

So, I don't see it as a disadvantage the 80 bears, but a vehicle that will give a ludicrously long service life in exchange for being inefficient with fuel. My brother in law bought his 93 within a month of mine. He has taken only casual care of it, has wheeled it, drove it with little gear oil in it for over a year until the front pinion bearings gave out, drove it all over the country, lent it to friends for months at a time and it now has 315,000 miles on it. I rode in it yesterday, and every single component still works, it has never failed to start on him, and there are no funny noises or other evidence of advanced wear.

These are tanks. Inefficient on purpose because every time a decision had to be made for a part to be more durable or more fuel efficient the engineers chose the former.

Contrast that with a friend's '93 Suburban. At 120k it needed a new tranny. At 180k both exhaust manifolds were noted by me to be badly cracked and several serious engine leaks present. At 200k I replaced the steering box for him (he's our youth pastor and the truck was donated to his use when new, but money's always an issue for pastors) and noted the entire front end - tie rods, suspension bushings, etc were in need of replacement. Today it has 250k miles on it and you have to really saw at the wheel to keep it in its lane on the freeway, the driver's seat is held up with a piece of wood, the engine and other trouble lights have been on so long they've long ago burned out, the heater works only on 1 speed, the glovebox falls open randomly, many trim pieces have fallen off, the rear suspension sags badly, I think its on its 3rd tranny, and only a couple windows still operate. This is a vehicle that has lived its entire life on a concrete road, save a camping trip here and there - tough conditions, eh?? And look at it. So, just a vignette about Suburbans since they were mentioned in the thread.

I understand the fuel economy angle, and for many it is puzzling how a 6 cylinder SUV with moderate power gets worse economy than an 8 cylinder SUV with lots of power. Toyota didn't prioritize economy, they chose durability - that's the answer.

10 years from now, we'll all be talking about this or that friend with an Escalade that has 150,000 miles in it and the Homelink system won't work, GM quit making updated DVDs for the navigation system, the stereo fuse blows whenever the passenger turns on their seat heater, the chrome on the wheels is peeling, the mechanism that adjusts valve timing needs replacement to the tune of $3500, and the digital dash intermittently fades out. We'll all be driving Cruisers - 40s/60s/80s/100s - and snickering about it. Nothing new. Nothing new...

DougM
 
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