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I brought a used 2016 Lexus RC 200T, basicly a 4 cylinder turbo, pretty good on gas mileage but when the turbo kicks he does take off.

My days of street drag racing are well over so really don't care about the 0-60 or 1/4 mile times.

So my question is : the manual recomends 91 octance, , but can't find it,  so 87 , 89, and 93.

my problem is 93 is about 70 cents more a gallon , I've read that if you mix 89 and 93 = you get 91,

so I've tried always filling the tank when it's 1/2 full with alternating 89 / 93.

So is either 89 or 93 bad for the engine? any thoughts?

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Octane rating is the measure of a fuel's ability to resist "knocking" or "pinging" during combustion, caused by the air/fuel mixture detonating prematurely in the engine.

 

Higher octane fuels are often required or recommended for engines that use a higher compression ratio and/or use supercharging or turbocharging to force more air into the engine. Increasing pressure in the cylinder allows an engine to extract more mechanical energy from a given air/fuel mixture but requires higher octane fuel to keep the mixture from pre-detonating. In these engines, high octane fuel will improve performance and fuel economy.

 

Using a lower octane fuel than required can cause the engine to run poorly and can damage the engine and emissions control system over time. It may also void your warranty. In older vehicles, the engine can make an audible "knocking" or "pinging" sound. Many newer vehicles can adjust the spark timing to reduce knock, but engine power and fuel economy will still suffer.

 

 

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You might be getting messed up by the American Numbers, 91 everywhere else in the world is pretty common for most cars and equals 87 in America. You need to know if they are asking for RON or MON or AKI grade 91.

https://www.google.com/search?q=european+vs+american+octane+ratings&sxsrf=ACYBGNR6QAqOgCEiUXspwxVvESB4AOudeA:1576170413706&tbm=isch&source=iu&ictx=1&fir=7cUzD8KhRV5YNM%3A%2CzfHF-gar-QT2pM%2C_&vet=1&usg=AI4_-kTnGXQkLy__0AJE1GCtPz3fpq64ag&sa=X&ved=2ahUKEwiF4vSszLDmAhVKILcAHVmOBswQ9QEwAHoECAMQAw#imgrc=7cUzD8KhRV5YNM:

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As for the internal combusting part of yer engine a water vapor system will work wonders

I had a Built 454 from a race car in a 3/4 ton flatbed chevy PU

I got a vapor kit and Loved it

Full of toys and pulling a camp trailer I used the left lane to pass mose everyone coming up the long steep grade from the Desert 

To test I shut it off running up the grade and could feel the loss of power right away going 10 mph shower, then flick it back on and you could feel the powre come back

Its trick was to help with the burning of fuel/air keeping it cooler and at the same time would clean any carbon buildup that caused pre-ignition  the pinging

... in effect it pumped up the Octane of the fuel mix but not the gas itself

System held a windshield wiper/washer tank and water lasted a few gas tank fills ... and just took water

Now with all the emission SHIT before and after the sparkie part no idea if it's still a good idea or not

Oh it came about for the AirForce in them Kool Fighter Prop HotRods we all love

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btw,  i always check the required octane and the cost to replace the tires when looking at a vehicle...    when I had my '94 integra gsr,   hi octane and the factory recommended Michelins were $195 apiece ..  i was used to paying $45 a tire for my RX-7..  talk about a heart stopper..

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It has a Toyota engine, the computer will manage the oxygen and burn times as it was designed to do, and as BOI Guy noted, it's almost definitely built to burn 87.

Do a mental tally of the few bucks you save each time you use the regular unleaded rather than the premium, and deposit that money into an account. By the time you're done with that Lexus, you can take the $2k or so from your savings and put it to your next car.

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Burning cheap gas in a turbo or supercharged engine is playing the old "You can pay me now or pay me later" game.

Boosted engines are already firting with detonation level cylinder pressures anyway so cheaping out on fuel is a mugs game.

At best you are going to lose significant performance through the computer dialing back ignition advance to compensate.

If it's capable of winding it back enough that is.

I've been driving supercharged Jag V8's for 8 years and I only put 93 in the tank - 92 if I tank up in the States because that's the highest I can find down there.

My wife put 91 in once by accident and I noticed the reduced power caused by the ignition retard.

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I'm not a mechanic, and it's been a long time since I stayed in a Holiday Inn Express,

but here's a pretty good article on Octane: https://www.hemmings.com/blog/2014/04/11/tech-101-octane-the-facts-and-the-fiction-behind-those-higher-priced-fuels/   

I had a Mercedes mechanic that i used for many years suggest that if I wanted to save a little money on fuel, once the car had over 150k (non-turbo) it will probably have lost enough compression that it would be more or less safe to run regular in it instead of High Test.  I waited another 10k and gradually started adding regular about 50/50 for a few thousand and eventually went to straight regular. I never had any engine issues with this car.

Top hydraulics is another story altogether. in hindsight I sometimes wish I'd poured a gallon of hightest on the top and lit a match ....

 

YMMV

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1 minute ago, warbird said:

It only takes a little bit of 93 to substantially raise the 87. It is not a linear effect.

or water

 

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2 minutes ago, DA-WOODY said:

or water

 

Water (vapor) adds a lot of oxygen  and absorbs a lot of heat as it goes from liquid to steam.  It is hard to tell of the compiter can adjust for the temp and  oxygen changes.

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8 minutes ago, warbird said:

Water (vapor) adds a lot of oxygen  and absorbs a lot of heat as it goes from liquid to steam.  It is hard to tell of the compiter can adjust for the temp and  oxygen changes.

or the rest of the temperamental crap all around the engine

But sure is the shit (in proper amount) in the explosive part

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56 minutes ago, DA-WOODY said:

or the rest of the temperamental crap all around the engine

But sure is the shit (in proper amount) in the explosive part

Nephew  has a 2002 GTI. Chipped, waste gated to 25 psi. With alcohol injection the car has dyno'd 350 hp. Alcohol carries a lot of oxygen and heat   absorption too.

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Thanks for all the input, I think for now , I'll mostly use 93 or 91 , and every other 1/2 tank fill with 89, 

2 interesting things the 93 might have been a deal breaker , I only found when the sales man showed how to open the gas cap , you need the key pod , paper work wass done, 

The second the finance department sold me a extended warranty which I didn't need as the orginally warranty was still good, When I found out I made a very loud stink in the showroom and got my money back, Warning DON"T LET THE FINANCE DEPT sell you ANYTHING it's a total rip off.

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8 hours ago, garuda3 said:

So is either 89 or 93 bad for the engine? any thoughts?

I built cabinets for a living, so I tend to listen to the people who do build cars as to what to use.

 

What I do know, (potentially with some incorrect details), is that higher octane means a resistance to burning/exploding.  With higher compression ratios, the heat and temperature builds faster during the compression stroke, which means that with a lower octane fuel, the burn can start too early, which causes knocking.  Which taken to an extreme can do fun things like crack pistons.

Less important with a grocery getter naturally aspirated engine with a lower compression ratio.  Your car likely has a fairly low compression ratio.  BUT, with forced induction the volumetric efficiency goes way up, and you will be squeezing more than the volume of the stroke and cylinder on the compression stroke, essentially raising the compression ratio.

Cool thing about computer controlled cars, and digital ignition systems, and Toyota knowing how people are, the computer essentially knows what's going on with each rotation of the crank, and in each cylinder.  It will retard timing, and defuel to protect itself.  But long term, that can cause carbon problems in the exhaust and valvetrain, plus potentially damage sensors.

All three vehicles in my house are turbo charged.  Diesels are a different set of rules with the pickup, but the two gas cars, we run premium.  Because while I do know some stuff, and I do have being a cabinetmaker in my pocket, I'm not a engineer.

Dump premium in it, hammer on the throttle once in a while.  That's what it was made to do.

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28 minutes ago, Hatin' life said:

Dump premium in it, hammer on the throttle once in a while.  That's what it was made to do.

Premium , for the few extra buckets , oh well,

It is good on US95, to do the speed limit 95

Ok so I'm driving on Alligator Alley doing 100, I look in the mirror and see lights flashing, so I nail it 110, 120, 130+ , so I say this is crazy , so I pull over, The highway patrolman gets out his car pissed and ask why I was going so fast, Well officer "my last wife ran off with a patrolman and I thought it was you" trying to return her, he let me go with a warning ! 

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2 hours ago, warbird said:

Nephew  has a 2002 GTI. Chipped, waste gated to 25 psi. With alcohol injection the car has dyno'd 350 hp. Alcohol carries a lot of oxygen and heat   absorption too.

Tho it(alcohol)'s discouraged whilst driving in Kalifornia

Where All Diesels now Must be Smogged

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9 minutes ago, DA-WOODY said:

Tho it(alcohol)'s discouraged whilst driving in Kalifornia

Why? It burns a lot cleaner and cooler than gas so presumably less NOx

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Actually you do - it's called ignition advance. Light it off a few degrees before the top of the stroke and by the time the flame move out the piston is just over the top.

The higher the RPM the more advance you need - 30 or more degrees is typical.

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Water Injection Wizardry

A water injection system can improve your gas mileage 20 to 50 percent.

By the MOTHER EARTH NEWS editors
| September/October 1979
 
 
 
 
 
 
  • 059 water injection 01.jpg
    The water injection system uses the feeder hose attached to the air filter cover to squirt water directly into the carburetor.
    PHOTO: MOTHER EARTH NEWS STAFF
 
  • 059 water injection 01.jpg
  • 059 water injection 02.jpg

During the second World War, fighter pilots could push a button and inject a stream of water into the turbochargers of their monstrous powerplants to get extra thrust on takeoff. Some time later, Chrysler (among other auto manufacturers) installed water injection on a number of its large displacement engines, again for a performance increase. Indeed, water injection—used to produce power increases—is nothing new.

But using "Adam's ale" to save gasoline sure is a change of pace! You see, until recently there just hasn't been any way to effectively control the volume and atomization of the tiny amount of fluid needed to adapt H20 injection to a small, economical engine. And typically enough, while big technology has failed to figure out how such regulation could be handled, a small back-lot entrepreneur (with a wealth of experience and ingenuity, but a paucity of dollars and degrees) has succeeded.

Pat Goodman installed his first water injection system (on a Porsche racing car) in 1964, and the racing organization responded by banning his device—it made the vehicle too fast! Undaunted, Pat decided that even if the racing establishment wasn't interested in "improving the breed," he was.

Today, several near-bankruptcies later, the innovative mechanic owns a vehicle that only the government could argue with: a 1978 Ford Fiesta that gets 50 MPG in normal around-town driving. (This impressive figure has been verified by a MOTHER EARTH NEWS staffer, who accompanied Goodman on a 48-mile jaunt around Winchester, Virginia. During the drive—which Pat accomplished with, if anything, more speed than normal—the small four-cylinder sipped only 0.95 gallon of unleaded gas.)

 
 

Back to Basics

Like most good ideas, the Goodman water injection design is an amazingly simple approach to a frighteningly complex problem. In fact, the production system is much less complicated than the prototype model. It consists only of an atomization nozzle, plus two one-way valves from squirt guns, some hose (to supply water to the "sprayer" and draw pressure from the emission system), and a one-gallon water tank.

The nozzle is screwed into the top of the air cleaner housing and sprays minute droplets of water into the carburetor throat in response to orders from the engine's stock smog-control devices.

 

Despite his occasional criticisms of the government's regulatory bureaucracies, Pat is graciously thankful for all the time and money they've spent developing his system's volume-control device: the smog pump. This air injection mechanism carefully monitors engine speed and load, and provides the pressure to activate the Goodman unit's water nozzle!

By restricting air pressure from the pump (either with a valve or by crimping the hose) to about 2 1/2 PSI at around 3,000 RPM (measured with a fuel-pressure gauge), the proper ratio of 5% water to 95% gasoline is assured. And at 5%—if the motor burns a gallon of gas every 45 miles, for example—the gallon of water will last about 900 miles.

How Does It Work?

So—you may be wondering—just how does water improve gasoline mileage? After all, plain old H20 won't burn. However, because water doesn't burn, the fluid does (in effect) raise the octane of the fuel!

This higher "flash point" produces three specific benefits (as well as some offshoots). First, because the water cools the gas-air mixture, there is greater potential for expansion (since pressure is directly proportional to temperature). Second, combustion turns the water droplets to vapor, which also helps create a pressure bonus (much as the same substance drives a steam engine).

Finally—and most significantly—the conversion of water to steam consumes heat (at a rate of about 1,100 calories per gram of the liquid) at a very critical instant. This absorption of heat prevents the temperature of combustion from rushing to a sharp peak (as it does in a standard engine) and then dropping rapidly off. Instead, the car's heat increases more slowly, reaches a lower peak, and descends much more gradually. (In addition, the longer overall combustion duration creates more pressure than does a standard engine's cycle.)

Thus water injection alone can make your engine more efficient (and gas-thrifty), but a good mechanic can easily improve upon such benefits! Goodman, for instance, runs his Fiesta at a 12.7:1 compression ratio. He can do this because the reduced temperature of combustion prevents the normal problems of pre-ignition and nitrous oxide emissions (which are produced in a high heat environment): In fact, Pat's little Ford recently loped through the EPA's rigorous (and—at $3,000—expensive) nitrous oxide test with only half the maximum legal emissions.

A high compression ratio can have many benefits, but for the most part such "pluses" involve increased power. Most folks assume—or have been led to believe—that more power means more gasoline consumption. Not so! A compression-ratio hike does not change either displacement or fuel flow, but only makes better use of the fuel that's available. In the Goodman Fiesta, more power means that less throttle can be used to travel at the same speed. That efficient gasoline use translates to better mileage ... as well as a boost in performance. (By the way, the pistons Pat used to raise the compression in his little Ford are obtainable from his auto parts store.)

If you're reluctant to tackle piston replacement, you can still enjoy an approximately 20% MPG improvement by installing a water injection system on your stock engine. Since Pat plans to sell an installation kit—including nozzle, one-way valves, water tank, related hardware, and detailed instruction book—which will be available (by the time you read this) for under $50, a water injection system should pay for itself (at the rate of about a penny per mile) just 5,000 miles down the road.

 

In addition, the system is so simple to install that it can be ready to run in less than two hours, and the only recommended maintenance is a nozzle-cleaning (with vinegar) every 20,000 miles.

However, the future of the Pat Goodman water injection system is still undecided. Amidst negotiations for distribution with a large New York firm, Pat received word about the possibility of pending EPA action against people who manufacture automobile engine accessories.

While MOTHER EARTH NEWS can fully understand why devices that make noise, spit out smog, or gulp gasoline should be controlled, allowances must be made for small manufacturers who can genuinely help us all. Today Pat is not allowed to install his nozzles (nor is any professional mechanic, without that $3,000 nitrous oxide test) despite their seeming benefits. Tomorrow he might not be allowed to make them at all.

 
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9 hours ago, SloopJonB said:

Burning cheap gas in a turbo or supercharged engine is playing the old "You can pay me now or pay me later" game.

Boosted engines are already firting with detonation level cylinder pressures anyway so cheaping out on fuel is a mugs game.

At best you are going to lose significant performance through the computer dialing back ignition advance to compensate.

If it's capable of winding it back enough that is.

I've been driving supercharged Jag V8's for 8 years and I only put 93 in the tank - 92 if I tank up in the States because that's the highest I can find down there.

My wife put 91 in once by accident and I noticed the reduced power caused by the ignition retard.

87 octane isn't cheap gas in my opinion, it's mid-grade. Cheap gas is 85 with ethanol.

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I’ve got magnets on my fuel line. Huge fuel savings! Now that This thread has convinced me of the advantages of water injection I should be able to save more gas than I buy. Gonna be great! Why didn’t Honda thing of this!?!

WTF!

But one other tidbit, and with a sailing angle: Having spent a great amount of time on remote islands in Micronesia I can confidently report that the ship only brings diesel and regular low-octane grade gasoline to the islands. By some other means a few...very few...barrels of some other concoction is imported which is mixed with the regular fuel on the island to magically increase the price. Probably alters the color, mostly. Says so right on the barrels which are stacked by the roadside.  It also seemed like the several major brands were restocked by the very same generic ship...the very same regular fuel magically becomes Shell or Chevron in the hose I guess. Kinda makes a joke of the whole marketing hype.

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2 hours ago, El Boracho said:

I’ve got magnets on my fuel line. Huge fuel savings! Now that This thread has convinced me of the advantages of water injection I should be able to save more gas than I buy. Gonna be great! Why didn’t Honda thing of this!?!

WTF!

But one other tidbit, and with a sailing angle: Having spent a great amount of time on remote islands in Micronesia I can confidently report that the ship only brings diesel and regular low-octane grade gasoline to the islands. By some other means a few...very few...barrels of some other concoction is imported which is mixed with the regular fuel on the island to magically increase the price. Probably alters the color, mostly. Says so right on the barrels which are stacked by the roadside.  It also seemed like the several major brands were restocked by the very same generic ship...the very same regular fuel magically becomes Shell or Chevron in the hose I guess. Kinda makes a joke of the whole marketing hype.

It's the same here in the USA. The filling stations tend to get their fuel from a preferred refinery only when it's reasonably for them to do do. But when the refinery is too far, then the fuel from the closest refinery is often used, and the fuel is generic fuel receives the branded additives.

For instance, in a 50-some mile radius of Sinclair, Wyoming, home to a major Sinclair refinery ... I'm told that every gas station gets their fuel from that refinery ... Sinclair stations obviously, but Shell too, and BP and Chevron and the unbranded nameless fuels, it all comes from that refinery. Then after it's pumped into the branded tanks, the branded additives are added.

I knew a real motorhead who became convinced that most of the fine port damage he saw on his high-efficiency engine upgrades were due to the branded additives with injector cleaners and top lubricants. He only bought fuel from the generic resellers, because they saved money by not supplementing with any additives at all.

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Here is what Lexus says

Quote

RC200t:
Select premium unleaded gasoline with an octane rating of 91 (Research Octane Number 96) or higher required for optimum engine performance. If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91). Use of unleaded gasoline with an octane rating lower than 91 may result in engine knocking. Persistent knocking can lead to engine damage and should be corrected by refueling with higher octane unleaded gasoline.

 

My 2006 and 2008 Lexi required the same but the language was less threatening and indicated regular grade fuel would provide lower performance and possible increased knocking. For efficiency and performance, most engines use knock sensors and will enrich the mixture, retard timing and make other adjustment that downgrade performance and efficiency.  When gas prices spiked quickly, this engineer reasoned that winter air (cooler intake temps) might allow me to run regular gas without too much compromise on a Beltway commute.  The car ran fine but the performance loss was substantial and very noticeable and my fuel mileage dropped so much that the cost per mile was pretty much the same. I sucked it up and went back to premium. 
 

if the manufacture says use premium, use it. Not being shitty, but If you gag at the running costs, maybe a different car would have been a better choice. Would you buy a one design and then put cheap Dacron sails on it because competitive laminates were too expensive?  
 

 

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7 minutes ago, billy backstay said:

Are there Sunoco stations in Jupiter?  In CT, they have 91, but nobody else seems to........

Use to sail from Port Jeff, CT river, essex, hamburge cove then out to block , new port. 

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1 minute ago, garuda3 said:

Use to sail from Port Jeff, CT river, essex, hamburge cove then out to block , new port. 

 

We lived on South Cove in Essex for 30 years, and good friends had a house at Block on Cormorant Cove.  When our kids were little, we spent every Easter and Columbus Day school holidays on Block with them, which was awesome, because the tourists were only there between Memorial day and Labor day.  In the summer we spent many weekends in Hamburg Cove in our 23' Mako rafted up with friends, swimming, eating, swilling beer, and swapping lies, while the kids swam.  When the kids moved south, we didn't use the Mako enough to justify keeping it....  Met Missus BB in Newport during the AC races in '83, when I was running a 65' IOR boat, those were the good old days!!!

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5 minutes ago, billy backstay said:

 

We lived on South Cove in Essex for 30 years, and good friends had a house at Block on Cormorant Cove.  When our kids were little, we spent every Easter and Columbus Day school holidays on Block with them, which was awesome, because the tourists were only there between Memorial day and Labor day.  In the summer we spent many weekends in Hamburg Cove in our 23' Mako rafted up with friends, swimming, eating, swilling beer, and swapping lies, while the kids swam.  When the kids moved south, we didn't use the Mako enough to justify keeping it....  Met Missus BB in Newport during the AC races in '83, when I was running a 65' IOR boat, those were the good old days!!!

Stayed either Essex yacht club or Essex island marina, closed the Gris a few times, some good stories of those times !

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2 minutes ago, garuda3 said:

Stayed either Essex yacht club or Essex island marina, closed the Gris a few times, some good stories of those times !

 

Was a member at EYC for 21 years and founding member of Essex Corinthian, but we dropped both when we were not using them at all.  Too busy working and raising a family.  Recently rejoined Corinthian.  The Gris is a "must see" visit, in Essex, if only for the maritime art and antique gun collection.  CT River Museum at the foot of Main is also worth a visit, and there is a brand new restaurant and bar at the Essex Boat Works, "Carlson's Landing".  The Black Seal, formerly Tumbledown's, is the local sailors pub of choice.....

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10 hours ago, El Boracho said:

I’ve got magnets on my fuel line. Huge fuel savings! Now that This thread has convinced me of the advantages of water injection I should be able to save more gas than I buy. Gonna be great! Why didn’t Honda thing of this!?!

WTF!

But one other tidbit, and with a sailing angle: Having spent a great amount of time on remote islands in Micronesia I can confidently report that the ship only brings diesel and regular low-octane grade gasoline to the islands. By some other means a few...very few...barrels of some other concoction is imported which is mixed with the regular fuel on the island to magically increase the price. Probably alters the color, mostly. Says so right on the barrels which are stacked by the roadside.  It also seemed like the several major brands were restocked by the very same generic ship...the very same regular fuel magically becomes Shell or Chevron in the hose I guess. Kinda makes a joke of the whole marketing hype.

when in SE asia,  they had jerry cans at the gas stations which had an octane additive,  there was none in the gas at that time.... my dad would pour some into the gas tank..

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13 hours ago, DA-WOODY said:

Water Injection Wizardry

A water injection system can improve your gas mileage 20 to 50 percent.

By the MOTHER EARTH NEWS editors
| September/October 1979
 
 
 
 
 
 
  • 059 water injection 01.jpg
    The water injection system uses the feeder hose attached to the air filter cover to squirt water directly into the carburetor.
    PHOTO: MOTHER EARTH NEWS STAFF
 
  • 059 water injection 01.jpg
  • 059 water injection 02.jpg

During the second World War, fighter pilots could push a button and inject a stream of water into the turbochargers of their monstrous powerplants to get extra thrust on takeoff. Some time later, Chrysler (among other auto manufacturers) installed water injection on a number of its large displacement engines, again for a performance increase. Indeed, water injection—used to produce power increases—is nothing new.

But using "Adam's ale" to save gasoline sure is a change of pace! You see, until recently there just hasn't been any way to effectively control the volume and atomization of the tiny amount of fluid needed to adapt H20 injection to a small, economical engine. And typically enough, while big technology has failed to figure out how such regulation could be handled, a small back-lot entrepreneur (with a wealth of experience and ingenuity, but a paucity of dollars and degrees) has succeeded.

Pat Goodman installed his first water injection system (on a Porsche racing car) in 1964, and the racing organization responded by banning his device—it made the vehicle too fast! Undaunted, Pat decided that even if the racing establishment wasn't interested in "improving the breed," he was.

Today, several near-bankruptcies later, the innovative mechanic owns a vehicle that only the government could argue with: a 1978 Ford Fiesta that gets 50 MPG in normal around-town driving. (This impressive figure has been verified by a MOTHER EARTH NEWS staffer, who accompanied Goodman on a 48-mile jaunt around Winchester, Virginia. During the drive—which Pat accomplished with, if anything, more speed than normal—the small four-cylinder sipped only 0.95 gallon of unleaded gas.)

 
 

Back to Basics

Like most good ideas, the Goodman water injection design is an amazingly simple approach to a frighteningly complex problem. In fact, the production system is much less complicated than the prototype model. It consists only of an atomization nozzle, plus two one-way valves from squirt guns, some hose (to supply water to the "sprayer" and draw pressure from the emission system), and a one-gallon water tank.

The nozzle is screwed into the top of the air cleaner housing and sprays minute droplets of water into the carburetor throat in response to orders from the engine's stock smog-control devices.

 

Despite his occasional criticisms of the government's regulatory bureaucracies, Pat is graciously thankful for all the time and money they've spent developing his system's volume-control device: the smog pump. This air injection mechanism carefully monitors engine speed and load, and provides the pressure to activate the Goodman unit's water nozzle!

By restricting air pressure from the pump (either with a valve or by crimping the hose) to about 2 1/2 PSI at around 3,000 RPM (measured with a fuel-pressure gauge), the proper ratio of 5% water to 95% gasoline is assured. And at 5%—if the motor burns a gallon of gas every 45 miles, for example—the gallon of water will last about 900 miles.

How Does It Work?

So—you may be wondering—just how does water improve gasoline mileage? After all, plain old H20 won't burn. However, because water doesn't burn, the fluid does (in effect) raise the octane of the fuel!

This higher "flash point" produces three specific benefits (as well as some offshoots). First, because the water cools the gas-air mixture, there is greater potential for expansion (since pressure is directly proportional to temperature). Second, combustion turns the water droplets to vapor, which also helps create a pressure bonus (much as the same substance drives a steam engine).

Finally—and most significantly—the conversion of water to steam consumes heat (at a rate of about 1,100 calories per gram of the liquid) at a very critical instant. This absorption of heat prevents the temperature of combustion from rushing to a sharp peak (as it does in a standard engine) and then dropping rapidly off. Instead, the car's heat increases more slowly, reaches a lower peak, and descends much more gradually. (In addition, the longer overall combustion duration creates more pressure than does a standard engine's cycle.)

Thus water injection alone can make your engine more efficient (and gas-thrifty), but a good mechanic can easily improve upon such benefits! Goodman, for instance, runs his Fiesta at a 12.7:1 compression ratio. He can do this because the reduced temperature of combustion prevents the normal problems of pre-ignition and nitrous oxide emissions (which are produced in a high heat environment): In fact, Pat's little Ford recently loped through the EPA's rigorous (and—at $3,000—expensive) nitrous oxide test with only half the maximum legal emissions.

A high compression ratio can have many benefits, but for the most part such "pluses" involve increased power. Most folks assume—or have been led to believe—that more power means more gasoline consumption. Not so! A compression-ratio hike does not change either displacement or fuel flow, but only makes better use of the fuel that's available. In the Goodman Fiesta, more power means that less throttle can be used to travel at the same speed. That efficient gasoline use translates to better mileage ... as well as a boost in performance. (By the way, the pistons Pat used to raise the compression in his little Ford are obtainable from his auto parts store.)

If you're reluctant to tackle piston replacement, you can still enjoy an approximately 20% MPG improvement by installing a water injection system on your stock engine. Since Pat plans to sell an installation kit—including nozzle, one-way valves, water tank, related hardware, and detailed instruction book—which will be available (by the time you read this) for under $50, a water injection system should pay for itself (at the rate of about a penny per mile) just 5,000 miles down the road.

 
 

In addition, the system is so simple to install that it can be ready to run in less than two hours, and the only recommended maintenance is a nozzle-cleaning (with vinegar) every 20,000 miles.

However, the future of the Pat Goodman water injection system is still undecided. Amidst negotiations for distribution with a large New York firm, Pat received word about the possibility of pending EPA action against people who manufacture automobile engine accessories.

While MOTHER EARTH NEWS can fully understand why devices that make noise, spit out smog, or gulp gasoline should be controlled, allowances must be made for small manufacturers who can genuinely help us all. Today Pat is not allowed to install his nozzles (nor is any professional mechanic, without that $3,000 nitrous oxide test) despite their seeming benefits. Tomorrow he might not be allowed to make them at all.

 

Shades of the 100 MPG carburetor that Detroit and the oil companies suppressed decades ago.

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So I just completed my first tank of 89/93 , and there's the results  gas mileage around town up from 22 mpg to 25 mpg. Car seem a little quicker, actual burn rubber for the first time since a got the car , and that was in the ECO mode, will take it easier from how on ! savings per tank full was about $3. which would equal $ 200 to $300 a year.

Next car I buy will burn 87!

thanks for alls input.

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18 hours ago, El Boracho said:

I’ve got magnets on my fuel line. Huge fuel savings! Now that This thread has convinced me of the advantages of water injection I should be able to save more gas than I buy. Gonna be great! Why didn’t Honda thing of this!?!

WTF!

 

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