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Toyota Supra Turbo 7M-GTE with R154 5-speed
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Actually I know the history pretty well. It's a one owner car (mine) and all stock. But back in the day, I could "point-and-pay" and didn't really pay that much attention to what the dealer did for repairs HG-wise. I'll recheck my receipts more closely.
Interesting that your car sat for 8 years. Mine has sat since 2007 because it was burning coolant but passed compression checks etc. The assumption was coolant erosion into the chamber of cylinder (#6?) because exhaust gas was found in the coolant. Was told to keep driving it but I was afraid to so it sat. Big mistake. Now the tranny has issues going into reverse, coolant light is always on no matter how far topped off, etc.
Welcome to the forums.
 

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What good is all the fame if you ain't fuckin' the models?
I see you drivin' a sportscar, ain't hittin' the throttle
And I be down, and do a hundred, top down and goggles
Get off the freeway, exit 106 and parked it
Ash tray, flipped it, time to spark it
Gucci collar for dolla
Nelly? I think I recognize the last 3 lines from like 20 years ago lol
 

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I drive 500 miles per week and have to fill once on Sunday and once during the week. I will do some A/B testing and see. I drive to maximize mpg, doing things like drafting behind an 18 wheeler. I’ll do a couple weeks worth of each and report back.
On another note, down here Buc-ee’s has ethanol free gas. I will see if I can get that and also do a $/mile comparison.
On my 88 turbo I went from the factory computer to aftermarket, sequential injection with modern injectors (WRX STI pinks), sequential ignition and slightly lean burn cruise (15.3:1 AFR) and I'm getting 8.4L/100km cruising at motorway speeds (~100-120km/h). That's 28 US mpg. Tuned for E5 95 european fuel, so E5 91 octane american.

Might be worth investing in a modern engine management system.
 

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90T
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Like every ECU it listens for knock and retards the timing from base if it hears bad things. Running regular especially with any mods will result in the ECU deciding to pull some timing in the next ignition event. It isn't slow...engines are slow. Even at redline an old CPU can do a lot of calcs between ignitions events.
 

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1989 Sport Roof White Pkg 7M-GTE + mods
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166 Posts
Discussion Starter · #48 ·
On my 88 turbo I went from the factory computer to aftermarket, sequential injection with modern injectors (WRX STI pinks), sequential ignition and slightly lean burn cruise (15.3:1 AFR) and I'm getting 8.4L/100km cruising at motorway speeds (~100-120km/h). That's 28 US mpg. Tuned for E5 95 european fuel, so E5 91 octane american.

Might be worth investing in a modern engine management system.
Okay...that is English to me in that I understand most of what you have written. I get using different injectors (mine came with 550's I opted to not install.) I don't completely understand sequential injection; I thought the car already injected fuel just ahead of the intake stroke for each cylinder. I understand that the fuel injection is controlled by an ECU, but I don't know a lot about installing a different one. From my limited knowledge, that could be as simple as unplugging one box and plugging in another. It seems to me that most ECU's are tuned for enhanced power. I understand lean/rich burn from flying airplanes wherein one controls the air/fuel mixture in flight but don't know how to modify that on a car.

I would certainly like to get 28 mpg if possible; my last fill up I calculated 18.5 mpg so a 40% improvement is very real.
 

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Okay...that is English to me in that I understand most of what you have written. I get using different injectors (mine came with 550's I opted to not install.) I don't completely understand sequential injection; I thought the car already injected fuel just ahead of the intake stroke for each cylinder. I understand that the fuel injection is controlled by an ECU, but I don't know a lot about installing a different one. From my limited knowledge, that could be as simple as unplugging one box and plugging in another. It seems to me that most ECU's are tuned for enhanced power. I understand lean/rich burn from flying airplanes wherein one controls the air/fuel mixture in flight but don't know how to modify that on a car.

I would certainly like to get 28 mpg if possible; my last fill up I calculated 18.5 mpg so a 40% improvement is very real.
Different injectors in my case wasn't more of a power perspective, but economy. Newer injectors have better spray patterns that allow for better atomisation, you just need to match the cone size to the intake path of your cylinder head (in other words, find injectors from a car with a similar distance from the injector to the valve). That in turn increases torque and fuel efficiency at low RPMs.
Sequential fuel to batch fuel isn't really all that different in terms of economy, but it makes things a fair bit smoother at lower RPMs as you have more consistent fuelling.
Sequential ignition does improve economy over a bigass wasted spark like what comes stock purely by reducing electrical system load (only sparks on the cylinder that needs it, so uses effectively half the power). COPs further boost efficiency by reducing losses. It's not a huge amount, mind.

None of this will make that 10mpg difference in our setups. You'll get the most improvements from tuning the fuel/spark tables for maximum torque per fuel unit throughout. Being on 264 cams certainly doesn't help your case either, especially not on a car that gets pottered around like yours does.

I'm on a very basic standalone (Speeduino-based), I imagine on a far more advanced ECU the likes of Haltech Elites or Link G4+s you could go even further down the efficiency path.
 

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Okay...that is English to me in that I understand most of what you have written. I get using different injectors (mine came with 550's I opted to not install.) I don't completely understand sequential injection; I thought the car already injected fuel just ahead of the intake stroke for each cylinder. I understand that the fuel injection is controlled by an ECU, but I don't know a lot about installing a different one. From my limited knowledge, that could be as simple as unplugging one box and plugging in another. It seems to me that most ECU's are tuned for enhanced power. I understand lean/rich burn from flying airplanes wherein one controls the air/fuel mixture in flight but don't know how to modify that on a car.

I would certainly like to get 28 mpg if possible; my last fill up I calculated 18.5 mpg so a 40% improvement is very real.
Being 4 cycle engines, each cylinder only fires every other revolution of the engine. Wastespark fires each cylinder every rotation whether it's a firing cycle or not. There's some emissions-related benefits to this which is why some engines like the VVTi 2JZ-GTE went back to wastespark over the direct fire Coil on Plug (COP) of the non-VVTi, but there's no performance benefit to wastespark. The benefit to direct fire coils for each cylinder is they're firing half as often for a given RPM, so it's almost always easier to get a stronger spark from direct-fire COP systems.

Injection is a little more complicated but basically it has to deal with the timing of the fuel injectors in relation to the firing cycle of each cylinder. Batch injection takes the nearest two cylinders in the firing sequence and opens the injectors for both at the same time, with the window of open-time being wide enough to catch both cylinders. Sequential injection times each injector specifically for that cylinder and that cylinder alone, so it takes twice the control outputs for a given engine. Batch injection was a lot more common on more primitive EFI systems with less processing power and injectior outputs. But on newer cars, almost all are fully sequential injection because of the fuel economy and emissions benefits at idle and lighter load. A full-ham 1000HP car that's drinking 1000HP worth of fuel out of 6 injectors won't see much if any peak torque or peak HP benefit from sequential injection (there's variables in the intake runner, intake port, etc that could come into play but that's a can of worms) but someone in a daily driver/max MPG situation would certainly benefit from it.

Different injectors in my case wasn't more of a power perspective, but economy. Newer injectors have better spray patterns that allow for better atomisation, you just need to match the cone size to the intake path of your cylinder head (in other words, find injectors from a car with a similar distance from the injector to the valve). That in turn increases torque and fuel efficiency at low RPMs.
Sequential fuel to batch fuel isn't really all that different in terms of economy, but it makes things a fair bit smoother at lower RPMs as you have more consistent fuelling.
Sequential ignition does improve economy over a bigass wasted spark like what comes stock purely by reducing electrical system load (only sparks on the cylinder that needs it, so uses effectively half the power). COPs further boost efficiency by reducing losses. It's not a huge amount, mind.

None of this will make that 10mpg difference in our setups. You'll get the most improvements from tuning the fuel/spark tables for maximum torque per fuel unit throughout. Being on 264 cams certainly doesn't help your case either, especially not on a car that gets pottered around like yours does.

I'm on a very basic standalone (Speeduino-based), I imagine on a far more advanced ECU the likes of Haltech Elites or Link G4+s you could go even further down the efficiency path.
Yes, modern injectors might be the most significant improvement in EFI tech over the past 20 years. Good injectors make tuning a standalone so much easier as the performance is much more consistent across the range of possible duty cycles and of course spray patterns/atomization have improved immensely over older fire-hose style single nozzle injectors, especially the common aftermarket injectors of the 90 through the mid 2000's.

This discussion makes me wonder about doing a tuning package for something like a VVTi 2JZ-GE NA-T engine making a fairly modest 300-350whp, but aiming for maximum MPG and fuel economy with an appropriately sized modern turbo and injectors for that goal.
 

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1989 Sport Roof White Pkg 7M-GTE + mods
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Discussion Starter · #51 · (Edited)
I have a dilemma here. I generally understand automotive engineering. I went to college initially on an engineering scholarship. I worked at a garage in high school 35 years ago and have the ability to do basic mechanical stuff. I can draw out on paper how an engine works and explain conceptually what is going on. I built a model manual transmission using erector set gears. Could I build an engine? Not likely. Do I get how it works? Absolutely.

I have as a big picture goal getting the more efficiency if I can out of a 35 year old engine platform and also maintaining for as long as possible. I started this thread wondering how changes in fuel affect this particular car so it is a logical corollary that modern other pieces, e.g. aftermarket injectors, could also help. I had never thought about changing that stuff, in large part because the aftermarket world for Supras has been primarily focused on performance and never having been a tuner it wasn't in the front of my thoughts.

I feel like I have two ways I can go. Choice one is the less desirable which is simply asking for help and having someone tell me "Here is exactly what you need to do." like I did with the cooling fans that eventually solved my overheating problem. (Thank you again for that.) Choice two is to learn about this but if that is the route I go I don't know where to start. I can read every thread here but that feels hit-or-miss. Based on this discussion, it seems like an aftermarket ECU could be something worth looking at but I don't know what kind of work that is and most importantly, what risk comes with it. I haven't the first idea how to start learning about engine tuning.

Edit: I have read Wreckless' upgrade FAQ. It is written for performance, however, so it isn't completely helpful except in presenting concepts about which I need to learn more. I went back and read the original listing for my car which includes "electronic boost controller" so it looks like I have some learning to do because I don't know if that is part of the ECU, in addition to the ECU, or even what specifically it does and what model it is.
 

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90T
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Bear in mind that automaker's have dumped billions into getting more efficiency out of their products. You are not going to get it from a few bolt-ons. Reducing internal friction through design of bearing, low-tension rings, 0W18 oil, and other components like direct drive oil pumps and so on has helped. So has 10 speed transmissions, low-friction drive train components, better aerodynamics, auto-shutoff at idle, ECU control of battery charging, and FEM analysis of combustion chambers. I mean if you want that efficiency, buy a new car. My tesla puts gas in the tank when I regen down a hill. New tech cannot always be backfilled into an old design.
 

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This discussion makes me wonder about doing a tuning package for something like a VVTi 2JZ-GE NA-T engine making a fairly modest 300-350whp, but aiming for maximum MPG and fuel economy with an appropriately sized modern turbo and injectors for that goal.
I believe you'd have a decent market. Most tunes I've seen focus on the engine driving well and making the most power possible, not necessarily being economical under normal driving conditions. Which is of course understandable, as that's where elbow grease needs to be applied. You can get an engine making good power relatively safely in an hour, but tuning it so it has the best fuel economy and drives as it rolled out the factory takes days.

Choice two is to learn about this but if that is the route I go I don't know where to start. I can read every thread here but that feels hit-or-miss. Based on this discussion, it seems like an aftermarket ECU could be something worth looking at but I don't know what kind of work that is and most importantly, what risk comes with it. I haven't the first idea how to start learning about engine tuning.
Essentially, yeah. I too started on this without having the slightest hint of a clue about engine tuning other than basic theory. On my side was that I'm no stranger to wiring and electronics don't scare me (electronics engineering hobbyist and hopefully soon by trade). It was a far bigger job than I anticipated, but now I can say it was worth it. Wasn't without its ups and downs, mind.

There's a reward in learning how to do stuff yourself and pulling through. But something like this you need to do at a point in life where you have the time and the effort to put into it, otherwise it'll become daunting and frustrating very fast.

Sadly there's not much in the way of turnkey setups for the 7M... and I wouldn't reuse the factory loom for an aftermarket EMS.
 

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Hardcore Night Warrior
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Different injectors in my case wasn't more of a power perspective, but economy. Newer injectors have better spray patterns that allow for better atomisation, you just need to match the cone size to the intake path of your cylinder head (in other words, find injectors from a car with a similar distance from the injector to the valve). That in turn increases torque and fuel efficiency at low RPMs.
Sequential fuel to batch fuel isn't really all that different in terms of economy, but it makes things a fair bit smoother at lower RPMs as you have more consistent fuelling.
Sequential ignition does improve economy over a bigass wasted spark like what comes stock purely by reducing electrical system load (only sparks on the cylinder that needs it, so uses effectively half the power). COPs further boost efficiency by reducing losses. It's not a huge amount, mind.

None of this will make that 10mpg difference in our setups. You'll get the most improvements from tuning the fuel/spark tables for maximum torque per fuel unit throughout. Being on 264 cams certainly doesn't help your case either, especially not on a car that gets pottered around like yours does.

I'm on a very basic standalone (Speeduino-based), I imagine on a far more advanced ECU the likes of Haltech Elites or Link G4+s you could go even further down the efficiency path.
This post, and I suppose your approach with how you did your car, is near exactly what I'd like to focus on when and if I were to do a 7M build. Essentially, updating it with 35 years of technical development to get the most efficient running 7M there's ever been. Injector updates, ditch the AFM, lighter stronger rotating assembly, ditching wasted spark, going coil over plug, head porting, crank/cam position sensor conversion and modern ECU to get those miserly fuel tables. I'm a big believer in improving engine performance and engine response by improving efficiencies. Big power isn't the goal, big efficiency is!

Your 88 turbo. Is it factory weight, hardtop, targa, any weight reduction like lighter wheels or CF hood or something, 5spd or A/T, what RPM are you geting those 28mpg at 100 kph? My idea of getting a 30mpg 7M based MA70 does seem pretty realistic after hearing about yours.
 

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1987 Toyota Supra
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I used to get 30mpg on my Supra back when I originally bought it and it was still stock. (Not hwy speeds)
Once the modifying started, I've never gotten close to that again.

I would imagine that with good EGR flow and slightly lean on AFR, you could get decent mileage while cruising.

Though my driving style in the Supra has very little cruising sections anymore.
Wouldn't net me much gain, as I am usually having too much fun with it.

Programming an Aftermarket ECU for efficiency would have a lot of tuners looking sideways with blank stares I would imagine.
That would take a lot of work and Dyno time to get it dialed in for efficiency and driveability.
But it is absolutely something that can be done.
OEM ECU's excel at that, but they have hundreds of hours of adjustments in them.

I've looked into doing this kind of thing on my Tribeca, I already have all the cables and software to do it.
Decided in the end not to screw with my S.O. daily driver, and just keep it reliable and trouble free instead.
 

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1989 Sport Roof White Pkg 7M-GTE + mods
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Discussion Starter · #56 ·
I am crossing my fingers that parts remain available to do this. I have clear title to a car that runs essentially like it did from the dealer for a total of about $16K. I have a lot of money to use over time to apply modern technology as I understand how to do so. My next projects in order are 1) replace the aftermarket rims & tires with OEM rims and tires 2) fix the fog lights.

I need to spend some time learning about tuning. I also need to learn more about what I actually have. The listing included a divorced downpipe and an electronic boost controller.
 

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Hardcore Night Warrior
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That would take a lot of work and Dyno time to get it dialed in for efficiency and driveability.
But it is absolutely something that can be done.
OEM ECU's excel at that, but they have hundreds of hours of adjustments in them.
That has also been a consideration of mine, as I figured Toyota already did all the hard work on that end of tuning and they do have hundreds of hours of adjustments, therefore keep the stock ECU. However, in my head, all I can think is that surely "we" have come far enough that a modern stand alone could do it better.

Edit: Just remembered Alex from Humble Performance comparing a Haltech stand alone he tuned and the numbers and ease of getting to those numbers, versus what the time it would've taken using a Hondata setup, which is factory Honda based, and the Hondata would've taken much longer/more difficult.
 

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1989 Sport Roof White Pkg 7M-GTE + mods
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Discussion Starter · #58 ·
That has also been a consideration of mine, as I figured Toyota already did all the hard work on that end of tuning and they do have hundreds of hours of adjustments, therefore keep the stock ECU.
In 1986 that was true. We have knowledge and technology today we didn't have back then. Injectors are a great example. Also, Toyota didn't plan on someone daily driving an A70 like a Camry. I need to optimize my car from idle to ~2400 rpm. I spend so little time above that it only has to be in the ball park.
 

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1987 Toyota Supra
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Yeah vehicle tech has come a long ways in 30 years.
There are gains and features to be had over the stock TCCS system.

As you said tuning tools are getting easier and smarter as the years go on also.
The hard part is going to be tuning for drivability in all the areas or scenarios you can imagine.
The harder part is when you encounter drivability problems or scenarios you never imagined.
To have a comfortable and reliable daily driver you need all these bases covered.
 

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1987 Toyota Supra
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All that being said though, I actually prefer the old TCCS setup.
It gives the car the character and feel I remember from the day I bought it.
I will likely keep it that way, as is.

I have other things running modern day setups, so I am in no way opposed to new tech. :) (Except the giant screens and no tactile feedback controls)
 
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