Author Topic: Probably a stupid question - premium fuel?  (Read 12867 times)

KBecks

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Probably a stupid question - premium fuel?
« on: March 11, 2014, 06:46:19 AM »
We have an older Acura TL - 200,000+ miles.   It specifies premium fuel.  I am happy that our Honda van takes regular fuel.   I believe my husband still puts premium fuel in the Acura.  But should he?????  Or should we try to save a few bucks on our fill-ups and use regular?

The car runs great, it has been awesome and we can probably keep it another couple years or more.  Love that!

But would you baby it with the gas?   Maybe yes since things are going good so far?

What do you say?

Gimesalot

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Re: Probably a stupid question - premium fuel?
« Reply #1 on: March 11, 2014, 07:08:45 AM »
This really depends on the car.  What year is it?  Can you find the compression ratio of the motor?

The difference in the grades of gas is the octane number.  The octane number is a simple measurement of the ability to withstand compression without ignition.  In gasoline engines, the air and fuel mixture is compressed then ignited by the spark plug.  If the octane of the fuel is too low, then the mixture could ignite by compression alone, causing a misfire.  Normally, the check engine light will come on, and you will hear knocking. It is very evident if you have put the wrong fuel in your car.

Most newer cars will adjust the fuel to air ratio to compensate for low octane fuel.  My husband used to drive a 2004 or 2005 Charger (I know), and he filled it with premium.  I told him to try regular, and the car worked just fine. 

rtrnow

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Re: Probably a stupid question - premium fuel?
« Reply #2 on: March 11, 2014, 07:59:34 AM »
As just stated most newer cars that require premium are smart enough to retard timing and avoid knocking on reg gas. However, that will usually sacrifice power and efficiency. Power may not matter to you, but with many cars the lower mpg of reg gas negates the savings when filling up. There are tons of honda/acura forums. I would read a couple of those and get some opinions.

daverobev

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Re: Probably a stupid question - premium fuel?
« Reply #3 on: March 11, 2014, 09:23:33 AM »
If the manual says fuel of type X is required, use type X. Otherwise it's bad for the engine.

If it says recommended you can use a lower grade.

MrCash

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Re: Probably a stupid question - premium fuel?
« Reply #4 on: March 11, 2014, 09:27:39 AM »
If the manual says fuel of type X is required, use type X. Otherwise it's bad for the engine.

If it says recommended you can use a lower grade.

Yep.  It could cost you much more in the long run if you blow an engine. 

okashira

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Re: Probably a stupid question - premium fuel?
« Reply #5 on: March 11, 2014, 09:31:09 AM »
MechE and recovered car nut here.

If it specifies premium - use it.

Your Acura is probably smart enough to retard timing in response to regular fuel, however you don't want it to.

1.) the engine won't be running optimally, as designed. retarded timing will result in less of a complete burn and less torque.
2.) there is no such thing as a 'regular fuel sensor' in a car. when you add regular to a car designed for premium, it will probably result in knocking and pinging. This is detonation and will kill your motor over time. However, your car has a knock sensor that's extremely fast to react. When knock is detected, it will immediately retard timing in response. It's so fast you probably won't hear any knocking. The problem is, there is no way for the engine to know that you haven't refilled it with premium. So it constantly advances the timing, listens for knock, then retards it again. It will be stuck in that cycle until you put premium back in.

As an MMM following, this should be a non issue, anyway. In my case, gas costs are about 1% of my gross income. If I had to use premium, that's just noise.

Spork

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Re: Probably a stupid question - premium fuel?
« Reply #6 on: March 11, 2014, 09:38:19 AM »

So what would you use for a high compression antique (carbureted no sensors whatsoever) when the manual says "never use under 100 octane".

The obvious answer is avgas, but ... that's a royal PITA to manage.

Mister Fancypants

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Re: Probably a stupid question - premium fuel?
« Reply #7 on: March 11, 2014, 10:18:19 AM »
As a previous owner of an Acura TL 2001, my guess is based on your mileage yours is of around that vintage or older use the premium, the engine will not retard the compression properly and will misfire, we always used premium, we discussed this with our mech.

It is worth the price to keep the engine running.

-Mister FancyPants

AccidentalMiser

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Re: Probably a stupid question - premium fuel?
« Reply #8 on: March 11, 2014, 10:34:17 AM »
Echo above.  If it says premium, premium it is.  Ping is awfully hard on your 200k baby!

Exflyboy

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Re: Probably a stupid question - premium fuel?
« Reply #9 on: March 11, 2014, 11:37:45 AM »
Okashira is correct, As a fellow mechanical, and airplane builder/pilot where we play constantly with making engines run properly at altitude we have a lot of knowledge on this subject.

detonation is the big risk.. where the mixture explodes uncontrollably in the cylinder, rather than burning gradually from one side of the cylinder to the other. This will cause a knock

Pre-ignition is a worse for of the above where the mixture ignites due to compression alone.. This will cause  BIG knock.

Modern cars for the most part will control detonation by retarding the timing so the spark form the sparkplug occurs later in the cycle. Pre-ignition cannot be controlled and the engine will sound very bad indeed.

Now I have a twin cam Dodge Neon that is supposed to run on premium. As I was driving 600 miles a week and I know the symptoms of detonation I decided to try regular fuel even though recommended is regular. This was after I rebuilt the engine.

bottom line is that there is slightly less performance but the MPG is the same (if it was detonating the mpg would almost certainly drop).

My guess would be your car will be fine as long as it has a modern (OBD 2) control system.. these came out in 1996 I believe.

I would be more cautious if the car does not have OBD 2.. It cartainly needs to have a knock sensor.. whcih your car may have even if it is older than that.

For and old car with a carburetor I probably wouldn't risk it.

Frank
« Last Edit: March 11, 2014, 11:56:01 AM by frankh »

Exflyboy

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Re: Probably a stupid question - premium fuel?
« Reply #10 on: March 11, 2014, 11:48:30 AM »
Don't get me wrong.. this is a risk to to try.

You could run the fuel down to almost empty and then try a couple of gallons of regular and see if it sounds normal,, if it pings or hesitates simply go back to the gas station and fill with premium. The small amount of regular will be insignificant and it should run normally.

Now the other thing to remember is the effects of altitude.. In Colorado (high altitude) the regular fuel is 85 octane.. in Oregon at low altitude its 87 Octane. They get away with this because because you need less detonation resistance at high altitude.

if your manual calls for 91 octane and if (for example) you live in Colorado you might not want to try 85 Octane fuel.. Go with 87 which is closer to mid grade in Colorado.

The other thing you can do is to drop to mid grade and try that first.

If you ask a mechanic you will always get the safe answer... Do what the manual says.. Well in my Airplane the engine was worth $30,000. the standard advice was .. never run it ion anything but 100 octane aviation fuel.

Well I ran that engine for 700 hours on premium (91 octane) autofuel.. it ran perfectly... I wasn't brave enough to drop to 87 Octane, but that was for a different technical reason.

If you do the research you might find there are a lot of old wives tales out there... But it is not a risk free endeavour however.

Frank

prodarwin

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Re: Probably a stupid question - premium fuel?
« Reply #11 on: March 11, 2014, 11:59:26 AM »

So what would you use for a high compression antique (carbureted no sensors whatsoever) when the manual says "never use under 100 octane".

The obvious answer is avgas, but ... that's a royal PITA to manage.

If the lines/seals can handle it... E85.

soccerluvof4

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Re: Probably a stupid question - premium fuel?
« Reply #12 on: March 11, 2014, 12:02:45 PM »
you got over 200k on a vehicle thats been nice to you it sounds? why change now. The increase in fuel could be minimal compared to Engine repairs that my pop up! If it aint broke dont fix it!

huadpe

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Re: Probably a stupid question - premium fuel?
« Reply #13 on: March 11, 2014, 01:09:40 PM »

So what would you use for a high compression antique (carbureted no sensors whatsoever) when the manual says "never use under 100 octane".

The obvious answer is avgas, but ... that's a royal PITA to manage.

avgas is heavily leaded, and illegal to use on roads.  http://www.fuelexpert.co.za/canirunavgas.php

Sunoco seems to sell bottled race fuel that would be road legal and is 100 octane plus.  You'd have to find a retailer who sells it near you.  http://www.racegas.com/fuel/compare 

Spork

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Re: Probably a stupid question - premium fuel?
« Reply #14 on: March 11, 2014, 01:19:30 PM »

So what would you use for a high compression antique (carbureted no sensors whatsoever) when the manual says "never use under 100 octane".

The obvious answer is avgas, but ... that's a royal PITA to manage.

If the lines/seals can handle it... E85.

Um.  NO.  Just no.  Ethanol lowers the octane... and is horrible on engines, especially older engines and small engines.  It also has a very low boiling point.  I get vaporlock on the E90 (the only option around here) in the summer.  E85 would not be an improvement.


avgas is heavily leaded, and illegal to use on roads.  http://www.fuelexpert.co.za/canirunavgas.php

Sunoco seems to sell bottled race fuel that would be road legal and is 100 octane plus.  You'd have to find a retailer who sells it near you.  http://www.racegas.com/fuel/compare 

It's a 1975 car.  It's made to run on leaded gas.  Ethyl (what used to be 100 octane in 1975) was highly leaded.  "Ethyl" is short for Tetraethyllead.  Running old cars on unleaded gas actually is hard on them.  The valve guides are made to be lubricated with lead. The only reason avgas is illegal to run is because it is a taxation issue.  Your taxes go to the aviation trust fund instead of funding roads.

Exflyboy

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Re: Probably a stupid question - premium fuel?
« Reply #15 on: March 11, 2014, 01:37:59 PM »

So what would you use for a high compression antique (carbureted no sensors whatsoever) when the manual says "never use under 100 octane".

The obvious answer is avgas, but ... that's a royal PITA to manage.

If the lines/seals can handle it... E85.

Um.  NO.  Just no.  Ethanol lowers the octane... and is horrible on engines, especially older engines and small engines.  It also has a very low boiling point.  I get vaporlock on the E90 (the only option around here) in the summer.  E85 would not be an improvement.


avgas is heavily leaded, and illegal to use on roads.  http://www.fuelexpert.co.za/canirunavgas.php

Sunoco seems to sell bottled race fuel that would be road legal and is 100 octane plus.  You'd have to find a retailer who sells it near you.  http://www.racegas.com/fuel/compare 

It's a 1975 car.  It's made to run on leaded gas.  Ethyl (what used to be 100 octane in 1975) was highly leaded.  "Ethyl" is short for Tetraethyllead.  Running old cars on unleaded gas actually is hard on them.  The valve guides are made to be lubricated with lead. The only reason avgas is illegal to run is because it is a taxation issue.  Your taxes go to the aviation trust fund instead of funding roads.

Valve seats actually.. Not sure if its a lubrication issue or if the lead lowers the combustion temperature thus does not burn the seats as fast when using a softer cast iron.

prodarwin

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Re: Probably a stupid question - premium fuel?
« Reply #16 on: March 11, 2014, 01:48:53 PM »

If the lines/seals can handle it... E85.

Um.  NO.  Just no.  Ethanol lowers the octane... and is horrible on engines, especially older engines and small engines.  It also has a very low boiling point.  I get vaporlock on the E90 (the only option around here) in the summer.  E85 would not be an improvement.[/quote]

I realize it may be bad for seals and whatnot on an old car.  You sure you don't mean E10 in summer (10% ethanol)?

E85 is commonly cited as 105-110 octane.  The lowest # I've seen for it is 94-96 octane as the result of some semi-recent study.  It has much better knock-resistance than premium fuel and burns cooler... many racers running lots of boost see enormous gains and use e85 as their "race fuel".

Won't solve the valve issues though, and probably requires a bunch of carb work since the volume of fuel required is significantly higher due to the lower energy density.

dragoncar

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Re: Probably a stupid question - premium fuel?
« Reply #17 on: March 11, 2014, 02:19:20 PM »
As a previous owner of an Acura TL 2001, my guess is based on your mileage yours is of around that vintage or older use the premium, the engine will not retard the compression properly and will misfire, we always used premium, we discussed this with our mech.

It is worth the price to keep the engine running.

-Mister FancyPants

I'll fifth this response.  It depends on what "older" means, but if it says premium use premium until you are absolutely sure it'll be ok on regular.  Honda would absolutely prefer to say "regular" whenever possible for marketing purposes - my Accord can use either (compression ratio of 10:1 and it will adjust timing based on knock detection) but states regular.  Therefore, I believe if it says premium they really mean it.

Those Acuras really do have a pretty high compression ratio. 

Exflyboy

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Re: Probably a stupid question - premium fuel?
« Reply #18 on: March 11, 2014, 02:35:32 PM »

If the lines/seals can handle it... E85.

Um.  NO.  Just no.  Ethanol lowers the octane... and is horrible on engines, especially older engines and small engines.  It also has a very low boiling point.  I get vaporlock on the E90 (the only option around here) in the summer.  E85 would not be an improvement.

I realize it may be bad for seals and whatnot on an old car.  You sure you don't mean E10 in summer (10% ethanol)?

E85 is commonly cited as 105-110 octane.  The lowest # I've seen for it is 94-96 octane as the result of some semi-recent study.  It has much better knock-resistance than premium fuel and burns cooler... many racers running lots of boost see enormous gains and use e85 as their "race fuel".

Won't solve the valve issues though, and probably requires a bunch of carb work since the volume of fuel required is significantly higher due to the lower energy density.
[/quote]

Correct pure ethanol has an octane rating of 116 I believe. The problem with ethanol is its just a poor fuel in that it does not contain much energy.. thus gives less MPG than gasoline.

huadpe

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Re: Probably a stupid question - premium fuel?
« Reply #19 on: March 11, 2014, 02:37:32 PM »
It's a 1975 car.  It's made to run on leaded gas.  Ethyl (what used to be 100 octane in 1975) was highly leaded.  "Ethyl" is short for Tetraethyllead.  Running old cars on unleaded gas actually is hard on them.  The valve guides are made to be lubricated with lead. The only reason avgas is illegal to run is because it is a taxation issue.  Your taxes go to the aviation trust fund instead of funding roads.

Leaded gas is illegal for road use.  If you want to buy some leaded racing gas really nobody is gonna stop you, but it's not legal.  You can use it for offroad or racing applications on private tracks, but it has been against the law since 1995 to operate a vehicle on public roads with leaded gasoline.  So yes, the tax is part of why avgas is illegal for road use, but it would be illegal to use even if it were taxed properly. 

If your car is a '75 you should be fine.  All 1975 and newer model year cars have to be able to take unleaded gasoline. http://web.mit.edu/ckolstad/www/Newell.pdf (PDF warning, cite is to last sentence of page 1)

Also, leaded gas is terrible for the environment/people who inhale the exhaust and really shouldn't be used even if you can get away with it. 

Spork

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Re: Probably a stupid question - premium fuel?
« Reply #20 on: March 11, 2014, 03:40:38 PM »

If your car is a '75 you should be fine.  All 1975 and newer model year cars have to be able to take unleaded gasoline. http://web.mit.edu/ckolstad/www/Newell.pdf (PDF warning, cite is to last sentence of page 1)


Imports lagged behind significantly.  My 75 was definitely made for leaded gas.  It never had a tank filler insert or a cat converter.  Neither did the 76 Triumph models.  I know 78's did...  but don't know about 77's.

Spork

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Re: Probably a stupid question - premium fuel?
« Reply #21 on: March 11, 2014, 03:54:07 PM »

Correct pure ethanol has an octane rating of 116 I believe. The problem with ethanol is its just a poor fuel in that it does not contain much energy.. thus gives less MPG than gasoline.

and it boils at 173 degrees... That's cooler than the water in the block and the air around the engine.

MrCash

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Re: Probably a stupid question - premium fuel?
« Reply #22 on: March 11, 2014, 04:00:13 PM »

Correct pure ethanol has an octane rating of 116 I believe. The problem with ethanol is its just a poor fuel in that it does not contain much energy.. thus gives less MPG than gasoline.

and it boils at 173 degrees... That's cooler than the water in the block and the air around the engine.

Interesting.  I did not know that.

Exflyboy

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Re: Probably a stupid question - premium fuel?
« Reply #23 on: March 11, 2014, 04:16:38 PM »
And that boiling point is at atmospheric pressure (sea level).. Lower the pressure and it boils at a lower temperature.

Thats why modern cars have the electric fuel pump in or near the gas tank... Sucking fuel uphill with a mecahnical pump on the back of a hot engine will cause it to boil and thus will vapour lock the fuel pump.

Frank

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Re: Probably a stupid question - premium fuel?
« Reply #24 on: March 11, 2014, 06:49:48 PM »
And that boiling point is at atmospheric pressure (sea level).. Lower the pressure and it boils at a lower temperature.

Thats why modern cars have the electric fuel pump in or near the gas tank... Sucking fuel uphill with a mecahnical pump on the back of a hot engine will cause it to boil and thus will vapour lock the fuel pump.

Frank

Unfortunately:  I am very aware of that.  The 10% solution currently boils in the summer.

I got to thinking:  I'm sorta being all complainypants here.  Technology changed and I'm trying to preserve a dinosaur and keep it semi-stock.  It's not like it is a particularly useful car.  It just has a lot of history/emotions tied to it. 

Exflyboy

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Re: Probably a stupid question - premium fuel?
« Reply #25 on: March 11, 2014, 06:54:13 PM »
Then rip out the mechanical fuel pump and put a solid state electric pump near the tank.. No more vapour lock.

Frank

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Re: Probably a stupid question - premium fuel?
« Reply #26 on: March 11, 2014, 06:57:08 PM »
Then rip out the mechanical fuel pump and put a solid state electric pump near the tank.. No more vapour lock.

Frank

That's one of the solutions.  I had really hoped to find a fuel solution, hence the complainypants.

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Re: Probably a stupid question - premium fuel?
« Reply #27 on: March 11, 2014, 07:03:16 PM »
By the time you have found the right fuel you'd be far better off sticking a little pump in there. Facet has a lot of them for various flowrates and pressures (you want about 2 to 5psi for a carb) and they are dead reliable.

I used two of them on the first airplane I built.

Frank

huadpe

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Re: Probably a stupid question - premium fuel?
« Reply #28 on: March 11, 2014, 07:48:12 PM »
Unfortunately:  I am very aware of that.  The 10% solution currently boils in the summer.

I got to thinking:  I'm sorta being all complainypants here.  Technology changed and I'm trying to preserve a dinosaur and keep it semi-stock.  It's not like it is a particularly useful car.  It just has a lot of history/emotions tied to it.

If it's gonna be a few miles every few months, just buy the leaded racing fuel.  It's probably substantially cheaper than modifying anything on the car.  Even at $10/gallon and getting poor mileage, you'd probably never recoup the cost of a new fuel pump.  If you're driving it more than that, then both cost wise and for the sake of those around you (especially any children you would take in it), get the fuel pump so you can go unleaded.

Spork

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Re: Probably a stupid question - premium fuel?
« Reply #29 on: March 12, 2014, 08:04:25 AM »
Unfortunately:  I am very aware of that.  The 10% solution currently boils in the summer.

I got to thinking:  I'm sorta being all complainypants here.  Technology changed and I'm trying to preserve a dinosaur and keep it semi-stock.  It's not like it is a particularly useful car.  It just has a lot of history/emotions tied to it.

If it's gonna be a few miles every few months, just buy the leaded racing fuel.  It's probably substantially cheaper than modifying anything on the car.  Even at $10/gallon and getting poor mileage, you'd probably never recoup the cost of a new fuel pump.  If you're driving it more than that, then both cost wise and for the sake of those around you (especially any children you would take in it), get the fuel pump so you can go unleaded.

The only stuff available around here is sold in cans and "offroad use only".   My first pass will probably be to insulate/heat shield the fuel lines.  That won't get it above 100 octane.. but it might at least slow down the vapor lock.

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Re: Probably a stupid question - premium fuel?
« Reply #30 on: March 12, 2014, 11:28:17 AM »
Solid state fuel pumps start at (or they did a couple of years back) around 30 bucks... Chump change compared with messing about with offroad fuels.

http://www.facet-purolator.com/cube-fuel-pumps.php

Frank

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Re: Probably a stupid question - premium fuel?
« Reply #31 on: March 12, 2014, 10:54:31 PM »
Imports lagged behind significantly.  My 75 was definitely made for leaded gas.  It never had a tank filler insert or a cat converter.  Neither did the 76 Triumph models.  I know 78's did...  but don't know about 77's.

What kind of import?  My '75 Scirocco was unleaded only.

daverobev

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Re: Probably a stupid question - premium fuel?
« Reply #32 on: March 13, 2014, 06:35:35 AM »
For the UK at least, my Vauxhall Nova was a 1984 or so; the 1.3l engine it had was about the last of those that would not run on unleaded fuel. The next revision had a 1.2 that would work with unleaded.

Spork

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Re: Probably a stupid question - premium fuel?
« Reply #33 on: March 13, 2014, 07:45:28 AM »
Imports lagged behind significantly.  My 75 was definitely made for leaded gas.  It never had a tank filler insert or a cat converter.  Neither did the 76 Triumph models.  I know 78's did...  but don't know about 77's.

What kind of import?  My '75 Scirocco was unleaded only.

Triumph is British.  Mine is a TR6, produced from 69-76 -- and no model ever was produced for unleaded.  I had a friend with a '78 Spitfire (produced 1962-80) that was made for unleaded.  Browsing through parts catalogs... it looks like Spitfire didn't have it in 75... but it's unclear what year it started because it's listed by VIN, not by year... maybe 76.  MGB looks like it started in 76.

That said: my 75 did have some emissions equipment (which was long gone by the time I got it).  It was just a form of exhaust gas recirculation back into the intake manifold.

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Re: Probably a stupid question - premium fuel?
« Reply #34 on: March 13, 2014, 03:46:21 PM »
Your Acura is probably smart enough to retard timing in response to regular fuel, however you don't want it to.

Reason #3 to add to your list:  Knock sensors do fail.  Usually a slow degradation due to getting beat up with knock noise.  It can be a very unhappy time when you find out that you have a dead knock sensor by way of needing engine work.

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Re: Probably a stupid question - premium fuel?
« Reply #35 on: March 13, 2014, 03:50:44 PM »
Correct pure ethanol has an octane rating of 116 I believe. The problem with ethanol is its just a poor fuel in that it does not contain much energy.. thus gives less MPG than gasoline.

Not only a solid decrease in MPG, but the decreased fuel density wreaks havoc on older (pre-OBD-2) cars with simple fuel injection (no knock sensor).  On pure gas, my 1991 MR2 ran fine on 87 octane.  Now that we're saddled with E10 in my region I have to run premium (93 octane minimum) to keep the knock down because the ECU can't handle it properly (verified during the transition when some stations had E10 and others had E0).  I'm considering installing larger injectors and a piggyback ECU to modify the fuel delivery, but honestly, it's just cheaper to buy premium and leave the car as-is.

TreeTired

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Re: Probably a stupid question - premium fuel?
« Reply #36 on: March 13, 2014, 04:15:53 PM »
I bought my 97 Lexus ES300 in 1996 and ran it on recommended premium gas until recently.  The past 3 or 4 years I have been using mid-grade with no noticeable difference,  187k miles.


I can find 100 octane racegas at some Marathon stations.  Many owners of older cars complain that the current ethanol mix damages rubber parts in the carburetors.   Premium gas without ethanol is still available around here but they want to charge almost $1 more per gallon  (!!!!!).  I think the boaters require it.

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Re: Probably a stupid question - premium fuel?
« Reply #37 on: March 14, 2014, 01:49:45 PM »
Yes ethonol is not compatible with the older style rummer seals, but it is compatible with later seals.. namely fluorosilicone (blue in clour) and Viton (usually brown).

Anything that has a black seal is suspect.

Frank

Primm

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Re: Probably a stupid question - premium fuel?
« Reply #38 on: March 17, 2014, 03:18:29 AM »
Unfortunately:  I am very aware of that.  The 10% solution currently boils in the summer.

I got to thinking:  I'm sorta being all complainypants here.  Technology changed and I'm trying to preserve a dinosaur and keep it semi-stock.  It's not like it is a particularly useful car.  It just has a lot of history/emotions tied to it.

If it's gonna be a few miles every few months, just buy the leaded racing fuel.  It's probably substantially cheaper than modifying anything on the car.  Even at $10/gallon and getting poor mileage, you'd probably never recoup the cost of a new fuel pump.  If you're driving it more than that, then both cost wise and for the sake of those around you (especially any children you would take in it), get the fuel pump so you can go unleaded.

The only stuff available around here is sold in cans and "offroad use only".   My first pass will probably be to insulate/heat shield the fuel lines.  That won't get it above 100 octane.. but it might at least slow down the vapor lock.

There's a fuel additive we get in Australia called Valve Saver. I'm not sure exactly how it works, but it's some sort of graphite-type lubricant that replaces the lead in fuel but without the detrimental to the environment effects. I carry around a little bottle and squirt it into the tank every time I fill up. Has kept my 1965 Datsun Sports chugging along way past 1M miles.

And yes, NEVER use ethanol based fuel in a brass based carburettor engine. Ethanol is heavily hydrophilic and will cause the needles and seats to corrode.