Fuel mileage improvements on the 3vze
03-17-2014, 07:13 AM
#61
Registered User
Yeah, new trucks/SUVs these days offset the fuel mileage by adding larger engines. If they had little 3.0L V6's though those new trucks would be getting in the 30's as far as MPG's goes. I think that's what he means (my wife's 4-cylinder Nissan gets 34 MPG mixed AND 200 HP...).
Back on topic, I forgot a huge one! Reduce the weight! Every 100 lbs you can take off the truck will boost your HP and MPG. Take off the camper shell you're not using, empty the bed/trunk, go on a diet (
), etc. If I had a place to store my camper shell and carpet kit it would be taking off about 150~ pounds.
BTW, on the topic of best mileage, on my way to get a new bumper in Modesto (before new injectors and intake which lowered my MPG's) I got 20.8 MPG on a road trip. It's possible. If I had taken the extra weight off, I'm sure that would have been in the 21's.
Back on topic, I forgot a huge one! Reduce the weight! Every 100 lbs you can take off the truck will boost your HP and MPG. Take off the camper shell you're not using, empty the bed/trunk, go on a diet (
), etc. If I had a place to store my camper shell and carpet kit it would be taking off about 150~ pounds.BTW, on the topic of best mileage, on my way to get a new bumper in Modesto (before new injectors and intake which lowered my MPG's) I got 20.8 MPG on a road trip. It's possible. If I had taken the extra weight off, I'm sure that would have been in the 21's.
03-17-2014, 08:41 AM
#62
Registered User
"Granny" shifting at 2000-2500 rpm won't do much for your mileage, but it will increase your chances of blowing a headgasket. Wide open throttle at low rpm's increases cylinder pressures, hastens the onset of knocking, raises combustion temperatures, and in general is not kind to your engine.
Hi rpm's are the 3vz's friend. I routinely shift at 3500-4000 rpm's and also routinely get 18-19 mpg.
Hi rpm's are the 3vz's friend. I routinely shift at 3500-4000 rpm's and also routinely get 18-19 mpg.
Last edited by jb451; 03-17-2014 at 08:43 AM.
03-17-2014, 09:21 AM
#63
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The definition of WOT has nothing to do with RPM, and for that matter, not all that much to do with accelerator or throttle position. As far as the engine is concerned, it is defined by near 0 inches of vacuum in the intake manifold. I would submit that if you are generating enough power to accelerate with a 22re or a 3vze at 2000 rpms, you probably pretty much have the throttle wide open by the above definition.
To see what's going on, run a vacuum line from your manifold to a vacuum gauge in the cab, and watch it while you're accelerating and shifting. If it gets near 0, for all practical purposes you are running at WOT, and the engine is gulping as much air as it can. Under those conditions, cylinder pressures are higher at low rpms than at higher rates, because the burn rate of the fuel is constant, and the piston is moving away from the pressure wave at a slower rate, allowing pressure to build up. That's also why engines tend to ping more at low rpms. The ECU compensates for this by retarding timing and enriching the mixture, both of which move the engine away from its peak thermodynamic efficiency and waste fuel as a result.
Drive however you want, but please know you are not doing your engine any favors by trying to get significant power out of it below 3000 rpm.
To see what's going on, run a vacuum line from your manifold to a vacuum gauge in the cab, and watch it while you're accelerating and shifting. If it gets near 0, for all practical purposes you are running at WOT, and the engine is gulping as much air as it can. Under those conditions, cylinder pressures are higher at low rpms than at higher rates, because the burn rate of the fuel is constant, and the piston is moving away from the pressure wave at a slower rate, allowing pressure to build up. That's also why engines tend to ping more at low rpms. The ECU compensates for this by retarding timing and enriching the mixture, both of which move the engine away from its peak thermodynamic efficiency and waste fuel as a result.
Drive however you want, but please know you are not doing your engine any favors by trying to get significant power out of it below 3000 rpm.
03-17-2014, 01:00 PM
#64
Registered User
The point about the 3.4 swap is that you get a +30% power gain with roughly the same mileage overall, and/or slight (1-2 mpg gains) if you drive a lot on highways/highway speeds.
This is despite the 3.4 5vzfe displacing 14% more volume (3378 cc) than the 3.0 3vze (2958 cc) -- more air in cylinders means more fuel being burned... Accordingly, assuming rough parity on mpgs, the 5vzfe is roughly 15% more efficient than the 3.0 to keep similar MPGs... But if it exceeds the 3.0's numbers (which I think it should and likely does), it should clock in at least 25% more efficient all factors considered.
My 3.0 V6 Ext Cab 4x4 pickup is rate 14/17 EPA. The next gen 3.4 V6 Ext Cab 4x4 Tacoma is rated 17/21. Tacoma weight is 3815 versus 3805 for the 3.0, so roughly equal. (These are both manual #s, despite myself driving an auto -- there are so many changes to transmissions that are tuned for fuel efficiency as well these days that looking at autos makes it such that you're comparing engines+transmission, full drivetrains, not the engines to engines... And the numbers are coming from Edmunds.) Oddly enough, the next gen 2.7L 4cyl extended cab 4x4 is rated 16/20 mpgs.
In the 3.0's stock form, you'd need a 20% improvement to hit 20mpg on the highway. I definitely think it's possible, but you'll also need a fully tuned engine to get there in addition to exhaust, driving habits, etc. Tuning and fixing the engine requires time and money. Distributor $150-$250, TPS $100, Wires $50, valve adjustment $500 to pay someone (totally worth it), fuel injectors $150, spark plugs $50, ISR delete $50, AFM swap $50, wideband O2 to do AFM swap $150, new 02 sensor $50, engine flush $10, power foam $20, seafoam $15, fuel injector cleaner $15, vacuum hose replace $50-100, water hose replace ~$200, gaskets ~$100, etc. Easily $1000k in just basic maintenance to get your engine tuned and in a reliable state after 20 years of service... Not sure what all you plan to do, but it's worth figuring out expected costs and incidentals on the front end.
Back to the swap -- generally speaking, I find that when I have/am driving a rig with a responsive and powerful engine, I use it more than I do w/ my 3vze. Harder driving due to different engine "operator zones" seems to negate some of the performance gains, real world differences, from what the scientific approach says should occur.
All that said, gotcha on not doing the swap. But my point about the swap is that your MPG savings from fixing various stuff and other tuning on your rig won't be working optimally until your whole system is tuned to work together. The 3vze is not an optimal engine for a lot of reasons, but how it breathes is a big hindrance to optimization. The 5vzfe fixes most of what was wrong with the 3.0 from an engine optimization standpoint, and the swap is cheaper than having the engine customized for performance, and is largely plug and play on our rigs. But if you know you'll never swap and/or live in the rust belt where your frame and body are nearly kaput, it changes things, which I guess is where you're at.
RJR -- yes, stuff like weight, speed, drag, etc, are easily controlled by "style" not not by substance if you will. They require no changes to mechanics of your rig to produce fuel savings.
lectric80 -- I looked at some #s and you were right about weight. Apparently, safety, comfort and the larger fuel tanks add up. Bear in mind that most of the truck class rigs are running larger engines too. Guess it strikes me as odd when stuff like wishbone suspensions versus axles and/or IFS, fiberglass and aluminum in place of steel, partially boxed frames, etc, are apples to apples lighter. Guess the sum of the parts adds up.
That said, a modern engine in our rigs should do even better from a weight perspective alone...
For a price perspective, if mostly city driving starting at 14-15mpg, each MPG improvement saves you about $150 annually per 10k driven. On the highway, that savings per MPG improvement reduces to about $100 in annual fuel savings per 10k driven.
This is despite the 3.4 5vzfe displacing 14% more volume (3378 cc) than the 3.0 3vze (2958 cc) -- more air in cylinders means more fuel being burned... Accordingly, assuming rough parity on mpgs, the 5vzfe is roughly 15% more efficient than the 3.0 to keep similar MPGs... But if it exceeds the 3.0's numbers (which I think it should and likely does), it should clock in at least 25% more efficient all factors considered.
My 3.0 V6 Ext Cab 4x4 pickup is rate 14/17 EPA. The next gen 3.4 V6 Ext Cab 4x4 Tacoma is rated 17/21. Tacoma weight is 3815 versus 3805 for the 3.0, so roughly equal. (These are both manual #s, despite myself driving an auto -- there are so many changes to transmissions that are tuned for fuel efficiency as well these days that looking at autos makes it such that you're comparing engines+transmission, full drivetrains, not the engines to engines... And the numbers are coming from Edmunds.) Oddly enough, the next gen 2.7L 4cyl extended cab 4x4 is rated 16/20 mpgs.
In the 3.0's stock form, you'd need a 20% improvement to hit 20mpg on the highway. I definitely think it's possible, but you'll also need a fully tuned engine to get there in addition to exhaust, driving habits, etc. Tuning and fixing the engine requires time and money. Distributor $150-$250, TPS $100, Wires $50, valve adjustment $500 to pay someone (totally worth it), fuel injectors $150, spark plugs $50, ISR delete $50, AFM swap $50, wideband O2 to do AFM swap $150, new 02 sensor $50, engine flush $10, power foam $20, seafoam $15, fuel injector cleaner $15, vacuum hose replace $50-100, water hose replace ~$200, gaskets ~$100, etc. Easily $1000k in just basic maintenance to get your engine tuned and in a reliable state after 20 years of service... Not sure what all you plan to do, but it's worth figuring out expected costs and incidentals on the front end.
Back to the swap -- generally speaking, I find that when I have/am driving a rig with a responsive and powerful engine, I use it more than I do w/ my 3vze. Harder driving due to different engine "operator zones" seems to negate some of the performance gains, real world differences, from what the scientific approach says should occur.
All that said, gotcha on not doing the swap. But my point about the swap is that your MPG savings from fixing various stuff and other tuning on your rig won't be working optimally until your whole system is tuned to work together. The 3vze is not an optimal engine for a lot of reasons, but how it breathes is a big hindrance to optimization. The 5vzfe fixes most of what was wrong with the 3.0 from an engine optimization standpoint, and the swap is cheaper than having the engine customized for performance, and is largely plug and play on our rigs. But if you know you'll never swap and/or live in the rust belt where your frame and body are nearly kaput, it changes things, which I guess is where you're at.
RJR -- yes, stuff like weight, speed, drag, etc, are easily controlled by "style" not not by substance if you will. They require no changes to mechanics of your rig to produce fuel savings.
lectric80 -- I looked at some #s and you were right about weight. Apparently, safety, comfort and the larger fuel tanks add up. Bear in mind that most of the truck class rigs are running larger engines too. Guess it strikes me as odd when stuff like wishbone suspensions versus axles and/or IFS, fiberglass and aluminum in place of steel, partially boxed frames, etc, are apples to apples lighter. Guess the sum of the parts adds up.
That said, a modern engine in our rigs should do even better from a weight perspective alone...
For a price perspective, if mostly city driving starting at 14-15mpg, each MPG improvement saves you about $150 annually per 10k driven. On the highway, that savings per MPG improvement reduces to about $100 in annual fuel savings per 10k driven.
Last edited by RSR; 03-17-2014 at 02:07 PM.
03-17-2014, 01:09 PM
#65
Registered User
How is 2000-2500 WOT? I think you may misunderstand, i drive my Runner like a grandpa. Literally.lol If i need to go faster, i shift into the next lower gear to accommodate, i know not to lug the engine. I've tried the high rpm shifting, it netted me worse mileage than granny shifting it. (14-15 iirc.) But i do 80-90% city driving, so i may differ from you of course. Driving the Camaro with no overdrive has taught me slower speeds and earlier shifts equals better mileage. Not the opposite. ymmv
03-17-2014, 08:51 PM
#66
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If I had only one modification to make for fuel mileage, it'd be a new exhaust. I bought my '88 PU with a 3.0, did all of the maintenance items that have been thoroughly discussed here, and didn't really see any improvement in mileage, but was happy with my work all the same. Before I swapped out my exhaust, I was getting around 17. My exhaust installer put in a Magnaflow cat-back with 2.25 inch piping, and I started seeing 19.5. The exhaust I pulled out was fairly new, but bargain-basement stuff, and the exhaust guy said the pipe was sized for a 4 cylinder rather than 6. I was pretty happy with the mileage gains, and doubly happy with a very noticeable horsepower gain. For around $300 this investment has some sweet rewards. Good luck.
03-17-2014, 09:28 PM
#67
In my case I'm not really in the rust belt, but the design on the rear mud flaps appears to be flawed. It looks like it pushes all the mist off the tires under the rear of the Runner, causing major rust. The front looks great, but the back half is pretty bad. That's why, in spite of it being an SR5, I can't justify spending a lot of coin on it.
However, as I have already pointed out, I'm nearly at 20 now with changes that cost very little to nothing. I'm already geting consistently in the 18-19 range, and I think I can push it up into the 20's with a bit more work. There are some things I suspect are wrong, and since I've only had it for a little over 2 weeks it is possible, so I'm going to be working to address them next. Things like the trans feels like it has GL5 in it, and I will be draining and refilling. Little stuff that, while costs will add up, won't really break the bank at this point.
RSR, now imagine if the modern vehicles out there didn't have to deal with all the extra weight and crap that the government forces on auto manufacturers, those new Tacoma's would be well into the 30 MPG range on gas, and we would have diesels here.
As for weight, there is no extra weight in my Runner, at least nothing except my fat butt. Since it is my daily driver, I don't load it with a ton of stuff. I don't even carry my tools because it is far easier to just have my wife or other family member bring me my tools than haul them around "just in case". I'm not sure how much weight I could really cut out of this thing at this point.
Edit: I keep hearing people talk about adjusting the TPS, so I may need to take a look at that. Luckily this site seems to have lots of good information I can pull from.
Granny shifting, or shifting below 3k doesn't seem to make sense to me. I know the way my truck feels, and above 3500 it feels like the power drops a lot, but up to that point it still pulls decent and that's why I typically shift around 3300. I can't see shifting sooner, except in town at low speeds, as having any benefit to the mileage.
However, as I have already pointed out, I'm nearly at 20 now with changes that cost very little to nothing. I'm already geting consistently in the 18-19 range, and I think I can push it up into the 20's with a bit more work. There are some things I suspect are wrong, and since I've only had it for a little over 2 weeks it is possible, so I'm going to be working to address them next. Things like the trans feels like it has GL5 in it, and I will be draining and refilling. Little stuff that, while costs will add up, won't really break the bank at this point.
RSR, now imagine if the modern vehicles out there didn't have to deal with all the extra weight and crap that the government forces on auto manufacturers, those new Tacoma's would be well into the 30 MPG range on gas, and we would have diesels here.
As for weight, there is no extra weight in my Runner, at least nothing except my fat butt. Since it is my daily driver, I don't load it with a ton of stuff. I don't even carry my tools because it is far easier to just have my wife or other family member bring me my tools than haul them around "just in case". I'm not sure how much weight I could really cut out of this thing at this point.
Edit: I keep hearing people talk about adjusting the TPS, so I may need to take a look at that. Luckily this site seems to have lots of good information I can pull from.
Granny shifting, or shifting below 3k doesn't seem to make sense to me. I know the way my truck feels, and above 3500 it feels like the power drops a lot, but up to that point it still pulls decent and that's why I typically shift around 3300. I can't see shifting sooner, except in town at low speeds, as having any benefit to the mileage.
Last edited by lectric80; 03-17-2014 at 09:31 PM.
03-18-2014, 05:51 AM
#68
You know, I've been reading this thread and thinking about how my auto handles shifting compared to how you guys are shifting in manuals. I totally agree, shifting shouldn't be done by some pre-conceived notion of lower rpm or even higher rpms. Every engine has it's power band where its most efficient to shift. But, I must say... the auto tranny does not shift at 3500 rpm unless i'm pushing it a bit. I can't imagine driving like that all the time though. I mean, the auto has technically a little less power and its less efficient but on streets and highways it rarely 'needs' to rev so high. I definitely do not strain the engine, nor do I push it when I feel it needs my patience.
I've been driving manuals for a while and every single engine needs it's own shifting pattern.
This is a good way to know if you are adding more than necessary fuel into your cylinders... If you push the throttle let's say 1/2 way, your car starts accelerating at let's say rate of Xmph/s, now if you were to release the throttle from 1/2 way to a 1/3 of the way and your acceleration is still Xmph/s (or near negligible difference), that means that you are straining your engine at 1/2 throttle and you shouldn't shift into the next gear yet if you want to accelerate. I hope this made sense to others..
I've been driving manuals for a while and every single engine needs it's own shifting pattern.
This is a good way to know if you are adding more than necessary fuel into your cylinders... If you push the throttle let's say 1/2 way, your car starts accelerating at let's say rate of Xmph/s, now if you were to release the throttle from 1/2 way to a 1/3 of the way and your acceleration is still Xmph/s (or near negligible difference), that means that you are straining your engine at 1/2 throttle and you shouldn't shift into the next gear yet if you want to accelerate. I hope this made sense to others..
03-18-2014, 05:33 PM
#69
Registered User
You know, I've been reading this thread and thinking about how my auto handles shifting compared to how you guys are shifting in manuals. I totally agree, shifting shouldn't be done by some pre-conceived notion of lower rpm or even higher rpms. Every engine has it's power band where its most efficient to shift. But, I must say... the auto tranny does not shift at 3500 rpm unless i'm pushing it a bit. I can't imagine driving like that all the time though. I mean, the auto has technically a little less power and its less efficient but on streets and highways it rarely 'needs' to rev so high. I definitely do not strain the engine, nor do I push it when I feel it needs my patience.
I've been driving manuals for a while and every single engine needs it's own shifting pattern.
This is a good way to know if you are adding more than necessary fuel into your cylinders... If you push the throttle let's say 1/2 way, your car starts accelerating at let's say rate of Xmph/s, now if you were to release the throttle from 1/2 way to a 1/3 of the way and your acceleration is still Xmph/s (or near negligible difference), that means that you are straining your engine at 1/2 throttle and you shouldn't shift into the next gear yet if you want to accelerate. I hope this made sense to others..
I've been driving manuals for a while and every single engine needs it's own shifting pattern.
This is a good way to know if you are adding more than necessary fuel into your cylinders... If you push the throttle let's say 1/2 way, your car starts accelerating at let's say rate of Xmph/s, now if you were to release the throttle from 1/2 way to a 1/3 of the way and your acceleration is still Xmph/s (or near negligible difference), that means that you are straining your engine at 1/2 throttle and you shouldn't shift into the next gear yet if you want to accelerate. I hope this made sense to others..
Idk fellas, i know how my truck runs and it runs just fine and i get my best mileage shifting like that. All my cars have been just fine driving that way, so i'm not concerned. Like i said, ymmv.
Also, i would advise changing the injectors to a set of flamethowers, i installed them today and i've got more usable power EVERYWHERE. Bet upgrade i've done hands down so far.
03-18-2014, 06:38 PM
#70
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You're right, there's some (a lot?) of "I shift that high because I can" going on with us 5-speed owners, for sure:-) At the same time, I have to believe the Toyota engineers cringed when they were told, for marketing reasons, that they had to figure out how to put an automatic behind the 3vze, and I'm sure the auto shift points were also heavily influenced by marketing for what would "feel and sound good" to the soccer moms they were hoping to sell to. They sure didn't put that automatic in there to try to improve the 0-60 times.
03-18-2014, 06:52 PM
#71
Registered User
You're right, there's some (a lot?) of "I shift that high because I can" going on with us 5-speed owners, for sure:-) At the same time, I have to believe the Toyota engineers cringed when they were told, for marketing reasons, that they had to figure out how to put an automatic behind the 3vze, and I'm sure the auto shift points were also heavily influenced by marketing for what would "feel and sound good" to the soccer moms they were hoping to sell to. They sure didn't put that automatic in there to try to improve the 0-60 times.
Man no kidding, my gf's with the 3.0/auto is god awful. I think i could beat it on a bicycle and 2 lengths back!
03-18-2014, 09:32 PM
#72
Like I said, mine feels like the right shift point is between 3200 and 3500, after 3500 the the engine starts to feel like it has no power. Now, there obviously could be things that could be done to improve that, but for right now my shifting is where I feel it needs to be for mileage and engine life.
Edit: I did the calculations after going back to 85 octane fuel for a tank and it does appear to be close to 1 MPG better with 89 octane. That tank I dropped back to 18.4 as compared to the 19.3 I had with 89. Guess I will continue to fuel with the slightly more expensive fuel.
Edit: I did the calculations after going back to 85 octane fuel for a tank and it does appear to be close to 1 MPG better with 89 octane. That tank I dropped back to 18.4 as compared to the 19.3 I had with 89. Guess I will continue to fuel with the slightly more expensive fuel.
Last edited by lectric80; 03-19-2014 at 01:38 AM.
03-19-2014, 08:16 AM
#73
Registered User
03-19-2014, 09:46 AM
#74
I'm not a fan of auto's to begin with.. and on the 3VZE it's that much less appealing. However, the rebuilt tranny in mine works very well. I finally got my gear shifter plastics in so I can now use the ECT button. I guess it's supposed to make a difference in shifting points.. we'll see how that feels. Worse comes to worse, we always have the option of keeping it at any gear with the gear selector 
03-19-2014, 10:21 PM
#75
My 22re is a different story, I typically pushed it well into the 4k range and mileage was good while it still pulled pretty good. That engine had less miles, but not by much, and a fresh cam and rockers.
03-28-2014, 12:19 PM
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If your 3vze starts fading above 3500 rpm something isn't right. It ought to pull strong up through 4500. Here's what I would check for starters:
- ignition timing - retarded timing will limit hi-rpm power
- Intake air flow. Could be obstructed, could just be that your accelerator linkage needs attention so that you can get the throttle wide open. There's a piece of rubber/plastic tubing where the cable attaches to the pedal linkage up under the dash that eventually often splits and reduces how far the pedal can pull the throttle cable open.
- Could also be a misadjusted/defective AFM that is not giving proper air flow information to the ECU.
- Fuel flow obstructions - not as likely unless you are also noticing misfiring at high rpms.
- ignition timing - retarded timing will limit hi-rpm power
- Intake air flow. Could be obstructed, could just be that your accelerator linkage needs attention so that you can get the throttle wide open. There's a piece of rubber/plastic tubing where the cable attaches to the pedal linkage up under the dash that eventually often splits and reduces how far the pedal can pull the throttle cable open.
- Could also be a misadjusted/defective AFM that is not giving proper air flow information to the ECU.
- Fuel flow obstructions - not as likely unless you are also noticing misfiring at high rpms.
03-28-2014, 08:11 PM
#78
I will start with timing, probably Sun. Then I will double check the throttle opening. It is better since cleaning the throttle body, but I will put it to the test tomorrow as we are taking it out to do a little wheeling.
03-29-2014, 12:00 AM
#79
Registered User
If your 3vze starts fading above 3500 rpm something isn't right. It ought to pull strong up through 4500. Here's what I would check for starters:
- ignition timing - retarded timing will limit hi-rpm power
- Intake air flow. Could be obstructed, could just be that your accelerator linkage needs attention so that you can get the throttle wide open. There's a piece of rubber/plastic tubing where the cable attaches to the pedal linkage up under the dash that eventually often splits and reduces how far the pedal can pull the throttle cable open.
- Could also be a misadjusted/defective AFM that is not giving proper air flow information to the ECU.
- Fuel flow obstructions - not as likely unless you are also noticing misfiring at high rpms.
- ignition timing - retarded timing will limit hi-rpm power
- Intake air flow. Could be obstructed, could just be that your accelerator linkage needs attention so that you can get the throttle wide open. There's a piece of rubber/plastic tubing where the cable attaches to the pedal linkage up under the dash that eventually often splits and reduces how far the pedal can pull the throttle cable open.
- Could also be a misadjusted/defective AFM that is not giving proper air flow information to the ECU.
- Fuel flow obstructions - not as likely unless you are also noticing misfiring at high rpms.
