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View Full Version : Regular, Mid or Premium


El Jeffe
06-06-2006, 11:36 AM
I've got to admit...Its getting really painful to fill up...

I have a 2000 ProStar 205...

Will I see a significant difference in performance or the like if I go to Regular Unleaded gas instead of premium?

Gas on Lake Washington is not cheap...

tommcat
06-06-2006, 11:51 AM
what does it call for?
if it says to use regular and you are using premium you are wasting money. a boat or car designed to run on regular will make less power and get worse fuel mileage when using premium.

erkoehler
06-06-2006, 12:04 PM
Which engine do you have in the boat?

rodltg2
06-06-2006, 12:25 PM
use the cheap crap

east tx skier
06-06-2006, 12:35 PM
Assuming you have the TBI, your manual says to use 89 octane, but you can get away with using 87. Your boat will retard the timing in the event of predetonation, and, as a result, your performance may suffer slightly.

With a carb boat, I run mid grade because it doesn't take long for 89 octane to get old and dip below 87. My boat won't do nice things like retard timing. As Enginenut has told us (with regard to the 351 at least), it will run on 87, but not so good on 85. MC recommends 89 in my application so it stands less chance of degrading below 87.

A tank of 89 costs $3 more than 87. I put 89 in my boat and stabilize it if it's going to sit more than a week or so.

El Jeffe
06-06-2006, 12:42 PM
So...Suck it up and fill with at least Mid...If I can...Put in the premium...


Assuming you have the TBI, your manual says to use 89 octane, but you can get away with using 87. Your boat will retard the timing in the event of predetonation, and, as a result, your performance may suffer slightly.

With a carb boat, I run mid grade because it doesn't take long for 89 octane to get old and dip below 87. My boat won't do nice things like retard timing. As Enginenut has told us (with regard to the 351 at least), it will run on 87, but not so good on 85. MC recommends 89 in my application so it stands less chance of degrading below 87.

A tank of 89 costs $3 more than 87. I put 89 in my boat and stabilize it if it's going to sit more than a week or so.

east tx skier
06-06-2006, 12:46 PM
If it's the TBI motor, you can run it all day on regular. The loss of performance would probably not be noticeable. My boat has a carb. So my situation is a bit different, which is why I throw down the extra $3 for 89 and stabilize it.

zberger
06-06-2006, 12:59 PM
The carb'd boat my buddy has we put premium in it, while it only has a 26 gallon tank or something.. we just take a 6 gallon jug with us each time we go, and throw it in the back of his truck then fill up a lil more each time, we are rarely if ever below a half tank anymore.. it works really well and just requires someone to pour it in.

The 87 at the lake I go to is 3.29 last I checked. I paid 2.89 for Premium at a gas station not far from my apartment :)

zberger
06-06-2006, 01:00 PM
If it's the TBI motor, you can run it all day on regular. The loss of performance would probably not be noticeable. My boat has a carb. So my situation is a bit different, which is why I throw down the extra $3 for 89 and stabilize it.

When you get ready to sell your boat, I want first dibs. :D

Kevin 89MC
06-06-2006, 01:08 PM
I've run 87 in my boat since day one. I do put Sea Foam in it almost every tank, and Sta-Bil in at the end of the season. Works for me & my pocketbook.

dog paw
06-06-2006, 01:14 PM
My 22 year old S+S has run on reg from day one. It still ran like a top last weekend :cool:

SkiDog
06-06-2006, 01:17 PM
use the cheap crap

Just what in the hell do you call Cheap??!?!?!?!?!?!?! $2.70? :eek:

86Craft
06-06-2006, 01:18 PM
I run 93 in my 86 with with a shot of lead substitute. I have no reason for the 93 octane, but the lead substitute has been used in this boat since it's first hour of use.

Granite_33
06-06-2006, 01:21 PM
I've got to admit...Its getting really painful to fill up...

I have a 2000 ProStar 205...

Will I see a significant difference in performance or the like if I go to Regular Unleaded gas instead of premium?

Gas on Lake Washington is not cheap...


Mine calls for 89 oct. Not sure what the price difference is between 87 and 89 on your lake. However, the way it is around here, there is a $.10 difference between regular and mid. I can use anywhere from 25 - 35 gallons per weekend in the boat, depending on weather, riders, use, etc, etc. $.10 x 35 gal.......is only $3.50.

I agree that saving anywhere you can helps out.......but to me.....the reaming we get for a gallon of regular is the big bite.......by the time you add another $.10 per gallon to use what Indmar specs.......I am numb anyways and figure that the extra $3.50 or so is worth it.

I can see your point, though if the differential between 87 and 89 is $.30 +

El Jeffe
06-06-2006, 01:23 PM
I'm not sure what TBI is...

But the engine is Fuel injected...

Also, what is "Sea Foam"

tommcat
06-06-2006, 01:39 PM
I'm not sure what TBI is...

But the engine is Fuel injected...

Also, what is "Sea Foam"
which motor though? LT1, MCX, Etc?

tommcat
06-06-2006, 01:41 PM
Just what in the hell do you call Cheap??!?!?!?!?!?!?! $2.70? :eek:
i wish it was that cheap here. i paid 3.70 last weekend for midgrade, of course he didnt even tell me it was midgrade until i was almost full :mad: . i know the LT1 is supposed to run super but it got me through the weekend ok.

kycat2007
06-06-2006, 01:44 PM
I have the LT1 and was considering some octane boost. I put regular in the tank and I am not getting any pinging noises. I hate to pay the extra as well but if I have to then I will. The octane boost usually treats like 15-20 gals of fuel and cost $4.99 a bottle. I think that has jet fuel in it or the STP says it does.

I do not want to damage my engine. I love that thing. But when I bought it, we put in some gas and the previous owner just put in some regular gas.

I will keep an I on it.

tommcat
06-06-2006, 01:47 PM
engine damage is not likely since the computer will back out timing until it doesnt ping. what you will notice is a loss of power from running less timing.

bigmac
06-06-2006, 01:54 PM
I use 91 octane non-oxygenated (no ethanol) from a 150 gallon portable fueler I haul down to the dock behind my John Deere. The local bulk supplier delivers it within 36 hours of calling him. Basically I pay pump price - my most recent fill was $2.80/gallon. It's a little higher now, but that 150 gallons oughta last me for another month or so.

tommcat
06-06-2006, 01:57 PM
How many of you guys are allowed to fill your boat from a gas can while on the water? it's illegal here and the fish cops can hand out big fines and take your boat if you get caught doing it.

kycat2007
06-06-2006, 01:57 PM
I got this off the web. I think I will have to do some adjusting when I can.
Q: What octane gas should I use in my car?

A: Well, once again, this is up to you, but first, lets explain what octane really is. Essentially, the higher the octane of gas, the more amount of oxygen it takes to burn the fuel. The more oxygen used to burn the gas means the quicker and cleaner it will burn. In larger, performance minded engines, you need to have a clean burning, fast fuel. Engines like the LS1 and LT1 have a computer, which is set to provide as much oxygen necessary to burn the fuel. Smaller displacement engines don't need a faster burning gas, and can get by with a lower octane gas, like 87. The computers in those cars are only set to give that engine so much oxygen per each spray of gas into the engine. If you put 93 octane gas in a car that's designed to run on 87, then the oxygen to gas ratio will be incorrect, and the fuel may not properly burn, thus harming the engine and performance of the car. So, getting to the point, if you run too low of an octane gas in an engine like the LS1, it is not putting more oxygen into the engine than necessary, so it will adjust the timing of the engine so it doesn't overdo it. Although this won't harm the engine, the fuel to air ratio will be less than optimal, and this will decrease your performance. So, running anything other than premium gas (which is usually between 92 and 94 octane depending on where you go) can potentially make your car run less than what it could. To be safe, the manufacturer recommends that you do not run anything lower than premium gas in the V8s.

6ballsisall
06-06-2006, 01:58 PM
We discussed this at MM2 but wanted to get this out there. Is there any reason you couldn't run farm fuel in our boats? They aren't driven on the roads so it would seem legal to me? Certain areas you can get gasoline (not diesel) in farm version (no taxes)

tommcat
06-06-2006, 02:01 PM
no need to get it off the web, i work on them for a living for Ford. i have to tell customers all the time to stop using premium when they dont need to. as soon as they do so they notice fuel mileage goes up and so does power.
here in the winter we also notice harder starting in the morning if running higher than need octane due to the fact that it's harder to ignite.

tommcat
06-06-2006, 02:03 PM
We discussed this at MM2 but wanted to get this out there. Is there any reason you couldn't run farm fuel in our boats? They aren't driven on the roads so it would seem legal to me? Certain areas you can get gasoline (not diesel) in farm version (no taxes)
it would be legal if available. we only have off road diesel around here though. i dont know about the gasoline you'd run but the diesel is of much worse quality here and WILL damage any of the newer trucks.
it destroys the injectors in a powerstroke very quickly due to high sulfur content.

shepherd
06-06-2006, 02:06 PM
It looks like the difference in price is $2.50 to $3.50 per tank of gas. I've paid more for that for a single beer (12 oz.!) at a bar.

It's all how you look at it. I use what the owner's manual calls for -- 89 octane.

WilliM1940
06-06-2006, 02:10 PM
I am running premium in my '85 with the lead substitue. Leaded premium is what it calls for in the manual, but no more leaded gas. Question is, why am I running premium in an engine with a low compression ratio like the 351 (I think it is 8.5 to 1 or less). What effect does the lead substitue have on octane rating if any? Is it because the Prestolite distrubutor with its advance curve is more aggressive than in a car, or is it because the engine is continuously loaded that this is a requirement? From what I see here, maybe I am wasting money...

WilliM1940
06-06-2006, 02:15 PM
More importantly, I am afraid of burning a valve if this old manual information is no good, I've been told higher octane, longer burn time, to the point it could still be burning when the exhaust valve opens. I am assuming the lead requirement is for soft valves on the older engines.

tommcat
06-06-2006, 02:18 PM
i know marine and automotive applications are different but coming from the auto industry i question why you'd need leaded fuel or lead additive in an '85 boat. the cars of the era were done using leaded fuel for years already, while i know marine is behind a bit i'd still think they'd be building them for unleaded fuel by then. :confused:

86Craft
06-06-2006, 02:25 PM
i know marine and automotive applications are different but coming from the auto industry i question why you'd need leaded fuel or lead additive in an '85 boat. the cars of the era were done using leaded fuel for years already, while i know marine is behind a bit i'd still think they'd be building them for unleaded fuel by then. :confused:

I thought the same thing, but it states on the sticker right on my valve covers not to use unleaded fuel, or to use a lead substitute. Also, it is in the PCM manual that came with the boat.

east tx skier
06-06-2006, 02:30 PM
When you get ready to sell your boat, I want first dibs. :D

Thanks! Although it doesn't look as if I'll be selling any time soon. :)

tommcat
06-06-2006, 02:30 PM
Strange.

if it makes you feel any better i ran unleaded in my 71 chevelle for years with no damage at all. i replace the motor for performance reasons about 5 years ago. when i tore down the original 307 it was perfect inside, and it ran unleaded for many years.

east tx skier
06-06-2006, 02:36 PM
I am running premium in my '85 with the lead substitue. Leaded premium is what it calls for in the manual, but no more leaded gas. Question is, why am I running premium in an engine with a low compression ratio like the 351 (I think it is 8.5 to 1 or less). What effect does the lead substitue have on octane rating if any? Is it because the Prestolite distrubutor with its advance curve is more aggressive than in a car, or is it because the engine is continuously loaded that this is a requirement? From what I see here, maybe I am wasting money...

The reason for the higher octane in a low compression engine is to avoid having the gas degrade over time (because most people don't religiously stabilize their fuel) to below 87 octane.

It will run fine on 87, but lower is a problem (according to our resident "Enginenut"). So if it's been sitting for a while unstabilized, you add 93 to get the overall degraded octane up.

east tx skier
06-06-2006, 02:40 PM
I'm not sure what TBI is...

But the engine is Fuel injected...

Also, what is "Sea Foam"

TBI is the standard throttle body injected Chevy 350. I can't remember what the HO option was in 2000, but it may have, like the LT1, required 93 octane. The TBI only requires 89 octane according to the manual.

Sea Foam is a fuel additive that's very good at removing carbon deposits. Half a can in the throttle body and half a can in the tank. Let it sit for 20 minutes and drive it hard. Makes for a nice smoke screen.

tommcat
06-06-2006, 02:44 PM
i can very highly recommend the Fitch Fuel catalysts. drop them in the tank and you never need to use any stabilizer again. it will actually increase the octane of the fuel a little.
i've been running them in snowmobiles for about 5 years now and every single one i've put them in got better fuel mileage and the fuel does not degrade at all. my buddy let his sit for 2 years and it was as good as new when he started it up last year.

east tx skier
06-06-2006, 02:51 PM
What do they cost?

tommcat
06-06-2006, 02:55 PM
What do they cost?I think it worked out to be a couple hundred bucks but it is well worth it to me. i'm not one to believe in any magic cure all but after quite a few years using them i swear by them.
check out their site

http://www.fitchfuelcatalyst.com/index.cfm

east tx skier
06-06-2006, 02:57 PM
I'll definitely give it a look, but fuel stabilizer only runs me about $8 per season.

Yes, I wish I could use the boat more than I do.

tommcat
06-06-2006, 03:00 PM
I'll definitely give it a look, but fuel stabilizer only runs me about $8 per season.

Yes, I wish I could use the boat more than I do.i like the performance gains you get too. i built to ZR900s a few years ago. one for me and one for my buddy. all mods were identical and i did all the work myself so i know there was no difference between them. i ran the fitch catalysts in mine, my buddy didnt. every single fill up i used 3 gallons less than him.

kycat2007
06-06-2006, 03:02 PM
Tommcat you are saying that you do not run high octane in your LT1 correct.
I just want to be sure of this because I do not have a manual on the LT1 in my boat.

tommcat
06-06-2006, 03:09 PM
Tommcat you are saying that you do not run high octane in your LT1 correct.
I just want to be sure of this because I do not have a manual on the LT1 in my boat.
i do run premium whenever possible. sorry if i wasnt clear, i tend to ramble sometimes.
i got stuck using midgrade last weekend, it seemed ok but i was only towing wakeboarders so i didnt have a huge load on it.

the manual clearly calls for premium. email mastercraft, they'll send you an owners manual for free :)

ajgressette
06-06-2006, 03:18 PM
I have always used the grade I think the station sells the most of. A lower grade of gas thatís fresh is more than likely better for your motor than 90 day old High Test that no one is willing to spend a fortune for. :steering:

tommcat
06-06-2006, 03:23 PM
we dont have a choice when buying on the water. all the marinas have one pump only and you get what they have or you get nothing.

NO GAS FOR YOU!

Kevin 89MC
06-07-2006, 11:15 AM
Sea Foam also is a fuel stabilizer - the main reason I run it in the spring/summer/fall. Sadly my boat will occasionally sit for a month or so, and I can go several months between filling up. Interesting read on their website http://www.seafoamsales.com it was oringinally developed for marine engines.

phecksel
06-07-2006, 11:30 AM
My 2003 197 requires 89 octane. I've noticed a huge performance between 87 & 89. Lesser difference between 89 & 91, but still some effect. % $ differrence between 87 & 91 is small. So, I run premium.

betsy&david Harrison
06-07-2006, 11:35 AM
I'll run what ever you bring. Just kidd'n .. I think we have premium in the gas tank at the lake that we use in the boat.

JimN
06-07-2006, 11:50 AM
kycat- from all of my training and everything I have ever heard, low octane burns faster with less compression than high octane. Generally, a high compression motor needs higher octane because of this. If the octane is low enough, you can pour it on a sidewalk and throw a match on it and it won't burn but hit it with a hammer and it'll light (JP-7 fuel for the SR-71 spyplane). The answers to that question has some problems. They're saying that the LT-1 and LS-1 need high octane because smaller engines don't need a faster burning gas. What do they call a non-injected 5.7L or a 351? Same size, different design and different octane requirements. Also, the computer is for delivering the right amount of fuel, based on the amount of air and they have this reversed. The computer may open the IAC but on a boat, there's no way to monitor the exhaust gases so it's a basic system anyway. In a low barometric pressure situation, it sounds like they're saying the computer can make more oxygen go into the motor when it's actually decreasing the amount of gas being injected. Again, the recommendation of using only premium is wrong for lower compression motors. If the manual says to use 87 or 89, use that unless the boat sits for long periods.

Tommcat- I assume the Ford ECM backs the timing off until it reaches base timing, right? Just trying to clarify that it can't go below that and for anyone with a distributor and injection, the base timing needs to be verified since the ECM doesn't know where the timing is set, it just knows that if it hears knock, it needs to back the timing off till there is either no knock or it reaches base timing.

JimN
06-07-2006, 11:55 AM
WilliM40- your motor was built after they eliminated lead and lead additive will not help. Your motor won't run better or last longer with or without it.

tommcat
06-07-2006, 12:45 PM
Tommcat- I assume the Ford ECM backs the timing off until it reaches base timing, right? Just trying to clarify that it can't go below that and for anyone with a distributor and injection, the base timing needs to be verified since the ECM doesn't know where the timing is set, it just knows that if it hears knock, it needs to back the timing off till there is either no knock or it reaches base timing.
jim, i dont know if it can bring it all the way down to base timing or not, i've never seen one pinging that bad. i have seen them take out a large amount of timing though and they ran like absolute garbage.
in theory though you are correct. it would only be able to bring it down to base timing, never below that.

tommcat
06-07-2006, 12:46 PM
WilliM40- your motor was built after they eliminated lead and lead additive will not help. Your motor won't run better or last longer with or without it.
but it is bad for the fishes ;)

BRAZOS 205
06-07-2006, 12:59 PM
My manual (1997) states 89 octane for the LT-1. I've been using 89 for the last 3 years. no problem.

tommcat
06-07-2006, 01:16 PM
My manual (1997) states 89 octane for the LT-1. I've been using 89 for the last 3 years. no problem.
thats strange, mine says to use premium :confused: same year, same engine.

JimN
06-07-2006, 02:11 PM
Tommcat- your motor has the crank wheel and there's no timing adjustment but on the TBI, the ECM is programmed to retard in 5 degree increments until it reaches base timing when it hears knock. This is specifically the reason we were told to verify base timing on all new boat setups and any time there was a performance issue where the timing seemed excessively advanced. The ECM, as I said, has no idea where base timing is and just assumes that it was set correctly which, as you know, can be a problem when the base timing was set to 20 BTDC and the advance curve tells it to add 40 degrees under load with bad gas on a hot dry day.

The lead is bad for the fishes and everything else that doesn't need it, like wake skiers.

tommcat
06-07-2006, 02:48 PM
so is the CKP actually adjustable on those engines?
ours can never be off because the CKP can only go in one place and cannot be moved.
the only time i've seen base timing off is when the crank trigger wheel has cracked and the ring rotated on the crankshaft a little bit. makes for a strange running engine with no obvious signs of whats wrong.

JimN
06-07-2006, 04:16 PM
Your crank wheel is one piece and IIRC, can only go on one way, too. Never heard of one cracking but occasionally a crank sensor goes bad or the plugs are on the wrong one. You have two and I have heard of a couple of repowers where they had a 'crank but no fire' situation and switching the crank sensor plugs took care of it.

tommcat
06-08-2006, 07:48 AM
i meant the junk i work on everyday (Fords), not my boat motor.

i really havent spent much time looking the LT1 over, i dont have a scan tool to read the data so it's no fun anyway ;)

BRAZOS 205
06-08-2006, 09:42 AM
Here is a page from my manual. 89 octane for LT-1.

tommcat
06-08-2006, 10:27 AM
i just re checked my manual, it does say 89. i dont know why i thought it said premium.
although i know they didnt take into account the ethanol blend fuel we're using around here now which does lean out the mixture. maybe premium is still a good idea since boats are open loop injection and have no way of knowing they are running lean?
i'll try 89 i mine next time (if it ever stops raining) and see how it likes it

El Jeffe
06-13-2006, 12:31 PM
OK...teh enigine in my boat is the Vortec 5.7L