Anyone ever installed bigger injectors?

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What does Toyota use on the 200 series? Are they still 4-hole? I have to imagine the best way to test their effectiveness is simply to track increases in MPG. While none of us has the ability to fully control the experiment (dyno, exact same grade of fuel, same weather conditions), the amount and conditions I drive doesn't vary much per week.
 
Are we interested in MPG or HP/torque improvements here?

If HP/Torque, it might be my memory failing or just a long week, but under WOT (like in dyno testing) won't the stock ECU be modulating fuel to hit its A/F target, so if you are burning more efficiently and therefore consuming more oxygen (no change in airflow right?) it throttles back the fuel, thereby reducing the potential for any real HP improvement? Not saying there wouldn't be something, but it might be at data noise levels, I would think. I mean, we're talking about a step improvement in atomization, not orders of magnitude, right?. I'm starting to doubt the benefit of asking for dyno anymore...

Then there's closed loop, where you are running off tables in the ECU. You could watch via ODB2 the STFT (short term fuel trims) pulling your LTFT into shape after changing the injectors, to then know that SOMETHING is happening. You couldn't correlate a % change to any sort of "improvement", especially since you would be swapping older injectors, possibly with reduced flow, for new full flow ones (as pointed out by @2001LC).

So perhaps a better measurement of an efficiency (and therefore MPG) improvement would be before & after emissions testing? I would expect that 'more efficient combustion from the 12 holes vs 4' would be revealed through reduced NOx and VOCs. This would be scientific on pretty reliable equipment available all over at relatively low cost.

Thoughts? Or has it just been a really long week for me... ? ;)
 
cruzerDave said:
Are we interested in MPG or HP/torque improvements here?

If HP/Torque, it might be my memory failing or just a long week, but under WOT (like in dyno testing) won't the stock ECU be modulating fuel to hit its A/F target, so if you are burning more efficiently and therefore consuming more oxygen (no change in airflow right?) it throttles back the fuel, thereby reducing the potential for any real HP improvement? Not saying there wouldn't be something, but it might be at data noise levels, I would think. I mean, we're talking about a step improvement in atomization, not orders of magnitude, right?. I'm starting to doubt the benefit of asking for dyno anymore...

Then there's closed loop, where you are running off tables in the ECU. You could watch via ODB2 the STFT (short term fuel trims) pulling your LTFT into shape after changing the injectors, to then know that SOMETHING is happening. You couldn't correlate a % change to any sort of "improvement", especially since you would be swapping older injectors, possibly with reduced flow, for new full flow ones (as pointed out by @2001LC).

So perhaps a better measurement of an efficiency (and therefore MPG) improvement would be before & after emissions testing? I would expect that 'more efficient combustion from the 12 holes vs 4' would be revealed through reduced NOx and VOCs. This would be scientific on pretty reliable equipment available all over at relatively low cost.

Thoughts? Or has it just been a really long week for me... ? ;)
Click to expand...

This represents my knowledge on older Toyota engines, but I assume the 2UZ is exactly the same:

Closed loop = normal driving

Open loop = WOT

Closed loop means the ECU is watching feedback signals (generally just an O2 sensor or two) and trimming fuel and sometimes timing to keep the output near stoich (14.7:1). Closed loop is where this mod would theoretically make an improvement as it would take less fuel to meet stoich because a higher percentage of fuel would be burned. The thought is that the 4 hole injectors atomize poorly and require more fuel to meet stoich. Extra fuel in the cylinder also means there's less volume for air and therefore less power potential for any given circumstance.

At WOT atomization means less. The airflow is very turbulent and, as a very generalized statement, the fuel is mixed rather well regardless of injector atomization. During WOT the ECU is "open loop" and doesn't really care what the O2 sensor reads. The engine has predefined maps that dictate how much fuel is to be added for a given set of inputs (throttle, load, VE, temp, pressure, airflow, RPM, etc...) and short of a catastrophic event (pinging/knocking detected, input sensor failure, etc...) the engine is going to inject X amount of fuel and hope for the best. OEMs are generally VERY, VERY safe on this part which means they add more fuel than is really necessary. More fuel means a richer AFR and less power, lower cylinder temps (liquid fuel absorbs a lot of heat) and reduced chance of pre-ignition (pinging/knocking). This is how "tuning" became a thing. OEMs started very rich, and then people took it upon themselves to lean out the WOT maps and gaining back the available power at the expense of increased risk for engine damage and accelerated wear. It's not that the tuning companies figured out anything OEMs don't know. The tuning company just doesn't care if the motor wears out 10 times as fast or produces more NOx.

Emissions testing varies from state to state, but in Colorado they do a varying speed run while sniffing the exhaust. The tester can be gentle or rough and getting consistent readings back and fourth would probably take 6 or more runs. The Cruiser is pretty easy, but watching them test the Supra with a hard clutch is both painful and hilarious. They'll miss a shift and then have to hammer the throttle to keep within their "test plan", but then boost kicks in and they overshoot. Funny stuff. Each run is $25 here, so that's a minimum of $150 in my mind. At that point, a couple hours on a dyno would be a much better investment, IMO. The emissions testing only gives you a few pollutant measures. No mention of AFR, no indication of power. I suppose you could sync it with some OBD datalog, but that'd be tough to correlate as you'd have a LONG set of data in the log and only single number outputs for the pollutants.

I do think a dyno would show the difference (if there is any), but now I'm also thinking simple OBD datalogs might show a difference in fuel trim for a given set of inputs. If you could take a bunch of data in similar environmental conditions both with and without the injectors you may be able to plot it all and see a difference. The only costs there would be time.

I'll play around with some logging with my rig as is and see if it looks promising.

Anyone else have an OBD scanner with logging ability? Maybe I could create a database of folks and see how similar we are in the "before" state.
 
suprarx7nut said:
This represents my knowledge on older Toyota engines, but I assume the 2UZ is exactly the same:

Closed loop = normal driving

Open loop = WOT

Closed loop means the ECU is watching feedback signals (generally just an O2 sensor or two) and trimming fuel and sometimes timing to keep the output near stoich (14.7:1). Closed loop is where this mod would theoretically make an improvement as it would take less fuel to meet stoich because a higher percentage of fuel would be burned. The thought is that the 4 hole injectors atomize poorly and require more fuel to meet stoich. Extra fuel in the cylinder also means there's less volume for air and therefore less power potential for any given circumstance.

At WOT atomization means less. The airflow is very turbulent and, as a very generalized statement, the fuel is mixed rather well regardless of injector atomization. During WOT the ECU is "open loop" and doesn't really care what the O2 sensor reads. The engine has predefined maps that dictate how much fuel is to be added for a given set of inputs (throttle, load, VE, temp, pressure, airflow, RPM, etc...) and short of a catastrophic event (pinging/knocking detected, input sensor failure, etc...) the engine is going to inject X amount of fuel and hope for the best. OEMs are generally VERY, VERY safe on this part which means they add more fuel than is really necessary. More fuel means a richer AFR and less power, lower cylinder temps (liquid fuel absorbs a lot of heat) and reduced chance of pre-ignition (pinging/knocking). This is how "tuning" became a thing. OEMs started very rich, and then people took it upon themselves to lean out the WOT maps and gaining back the available power at the expense of increased risk for engine damage and accelerated wear. It's not that the tuning companies figured out anything OEMs don't know. The tuning company just doesn't care if the motor wears out 10 times as fast or produces more NOx.

Emissions testing varies from state to state, but in Colorado they do a varying speed run while sniffing the exhaust. The tester can be gentle or rough and getting consistent readings back and fourth would probably take 6 or more runs. The Cruiser is pretty easy, but watching them test the Supra with a hard clutch is both painful and hilarious. They'll miss a shift and then have to hammer the throttle to keep within their "test plan", but then boost kicks in and they overshoot. Funny stuff. Each run is $25 here, so that's a minimum of $150 in my mind. At that point, a couple hours on a dyno would be a much better investment, IMO. The emissions testing only gives you a few pollutant measures. No mention of AFR, no indication of power. I suppose you could sync it with some OBD datalog, but that'd be tough to correlate as you'd have a LONG set of data in the log and only single number outputs for the pollutants.

I do think a dyno would show the difference (if there is any), but now I'm also thinking simple OBD datalogs might show a difference in fuel trim for a given set of inputs. If you could take a bunch of data in similar environmental conditions both with and without the injectors you may be able to plot it all and see a difference. The only costs there would be time.

I'll play around with some logging with my rig as is and see if it looks promising.

Anyone else have an OBD scanner with logging ability? Maybe I could create a database of folks and see how similar we are in the "before" state.
Click to expand...
Yep, running torque. Interested in looking over some data for the potential benefits of these and would be happy to contribute to the 'before' state.
 
Asanka said:
We're u getting ~330 per tank before installing injectors? Do u have a long range tank or what mods pls?
Click to expand...

His odometer is set to KM, not Miles. I did a double take as well. 351KM = 218 Miles.
 
DAMN...17 mpg... congrats!
 
Here's a quick plot from my drive into work today. I think this might be the chart that would show the injector improvement. It plots Fuel Flow vs Air Flow. The 3D plot on the right shows RPM in the vertical and colors by Throttle position. Notice how perfectly linear the relationship is between fuel flow and mass air flow. There are only a couple outliers out of around 500 data points. All data was recorded after ~10 minutes of driving so the engine was fully warm.

My theory is that if the new injectors improve anything, the ECU should pick up on the lower fuel requirement and trim fuel. You'll then have a different slope in the linear fit line and an objective % difference in injector performance.

I'll track it a few times and see how consistent my slope is. If it's consistent, you'd expect to see an increase in the slope as I have it plotted if the injector efficiency increases.

Fuel Flow Example 1.webp
 
After some poking around I saw that someone installed RX8 red injectors into their 4.7 with good results so I grabbed a set. May require some plug adapters I'm not sure yet. They are 350cc and the right ohms and also 12-hole.

People are talking about a plastic Tundra intake manifold as being a good upgrade for the 100 series. Does this apply to the later model 06-07 VVTi trucks or do these motors already have it?
 
If you live in CO then you're likely not hitting enough load at WOT to go open loop and car probably runs closed loop all of the time. Hard to know without doing the testing. Many cars and manufacturers do it differently some are rich at WOT some are lean some are perfect. I don't think I've seen a stock dyno run of one of these trucks that showed the A/F ratio so it's everyone's best guess.

suprarx7nut said:
This represents my knowledge on older Toyota engines, but I assume the 2UZ is exactly the same:

Closed loop = normal driving

Open loop = WOT

Closed loop means the ECU is watching feedback signals (generally just an O2 sensor or two) and trimming fuel and sometimes timing to keep the output near stoich (14.7:1). Closed loop is where this mod would theoretically make an improvement as it would take less fuel to meet stoich because a higher percentage of fuel would be burned. The thought is that the 4 hole injectors atomize poorly and require more fuel to meet stoich. Extra fuel in the cylinder also means there's less volume for air and therefore less power potential for any given circumstance.

At WOT atomization means less. The airflow is very turbulent and, as a very generalized statement, the fuel is mixed rather well regardless of injector atomization. During WOT the ECU is "open loop" and doesn't really care what the O2 sensor reads. The engine has predefined maps that dictate how much fuel is to be added for a given set of inputs (throttle, load, VE, temp, pressure, airflow, RPM, etc...) and short of a catastrophic event (pinging/knocking detected, input sensor failure, etc...) the engine is going to inject X amount of fuel and hope for the best. OEMs are generally VERY, VERY safe on this part which means they add more fuel than is really necessary. More fuel means a richer AFR and less power, lower cylinder temps (liquid fuel absorbs a lot of heat) and reduced chance of pre-ignition (pinging/knocking). This is how "tuning" became a thing. OEMs started very rich, and then people took it upon themselves to lean out the WOT maps and gaining back the available power at the expense of increased risk for engine damage and accelerated wear. It's not that the tuning companies figured out anything OEMs don't know. The tuning company just doesn't care if the motor wears out 10 times as fast or produces more NOx.

Emissions testing varies from state to state, but in Colorado they do a varying speed run while sniffing the exhaust. The tester can be gentle or rough and getting consistent readings back and fourth would probably take 6 or more runs. The Cruiser is pretty easy, but watching them test the Supra with a hard clutch is both painful and hilarious. They'll miss a shift and then have to hammer the throttle to keep within their "test plan", but then boost kicks in and they overshoot. Funny stuff. Each run is $25 here, so that's a minimum of $150 in my mind. At that point, a couple hours on a dyno would be a much better investment, IMO. The emissions testing only gives you a few pollutant measures. No mention of AFR, no indication of power. I suppose you could sync it with some OBD datalog, but that'd be tough to correlate as you'd have a LONG set of data in the log and only single number outputs for the pollutants.

I do think a dyno would show the difference (if there is any), but now I'm also thinking simple OBD datalogs might show a difference in fuel trim for a given set of inputs. If you could take a bunch of data in similar environmental conditions both with and without the injectors you may be able to plot it all and see a difference. The only costs there would be time.

I'll play around with some logging with my rig as is and see if it looks promising.

Anyone else have an OBD scanner with logging ability? Maybe I could create a database of folks and see how similar we are in the "before" state.
Click to expand...
 
J1000 said:
If you live in CO then you're likely not hitting enough load at WOT to go open loop and car probably runs closed loop all of the time. Hard to know without doing the testing. Many cars and manufacturers do it differently some are rich at WOT some are lean some are perfect. I don't think I've seen a stock dyno run of one of these trucks that showed the A/F ratio so it's everyone's best guess.
Click to expand...

Isn't WOT determined by the TPS and not load?
 
After messing with my truck and my OBD scanner I found that the truck goes 12:1 AFR at WOT. I am not 100% sure but I think the 2UZFE in our trucks has wideband O2 sensors so it should be pretty accurate. In this case in open-loop the larger injectors would likely give too much fuel and you may actually lose peak HP, but like others have said the rest of the time at partial throttle everything will be better.

The app I was using (Torque) did not have the open/closed loop indicator for me to choose so I couldn't see when/if it's changing. It was holding a good mid-14 AFR until reaching 85-90% throttle and then it goes 12:1, but my Honda does that too and stays in Closed-Loop the whole time.

More testing to come!
 
J1000 said:
After some poking around I saw that someone installed RX8 red injectors into their 4.7 with good results so I grabbed a set. May require some plug adapters I'm not sure yet. They are 350cc and the right ohms and also 12-hole.

People are talking about a plastic Tundra intake manifold as being a good upgrade for the 100 series. Does this apply to the later model 06-07 VVTi trucks or do these motors already have it?
Click to expand...
 
^^I dunno if that's a dig at me or not. Yes I ordered 350cc injectors and I could be right that they will cause me to lose HP! Only way to know is to try. Luckily, when buying used automotive parts; you can test them out and if they don't work turn around and sell them for the same price you bought them for! Amazing!

I am also going to convert my truck to E85/Flex Fuel so I will need larger injectors regardless and maybe an adjustable fuel regulator.
 
J1000 said:
^^I dunno if that's a dig at me or not. Yes I ordered 350cc injectors and I could be right that they will cause me to lose HP! Only way to know is to try. Luckily, when buying used automotive parts; you can test them out and if they don't work turn around and sell them for the same price you bought them for! Amazing!

I am also going to convert my truck to E85/Flex Fuel so I will need larger injectors regardless and maybe an adjustable fuel regulator.
Click to expand...

No, I was just reiterating your question as I was curious too. This thread seemed active then suddenly died off.
 
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