Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Happy holidays every one! ... bought the toro 1028 OXE back in October, right after the very first early snow storm. Was not able to try it in snow... I added the startron stabilizer And filled up the tank with 93 octane. I tested the new baby, showed off without spinning augers... But now it's a long time unused. My question is: is it okay for the fuel to sit in the carb for such a long time? Thanks!

JoelKlein wrote:
Help me out here.....

How does the octane rating of the fuel have such an effect on the gear ratio?   Constant engine rpm in a particular gear should, in most cases, deliver the constant speed.  If you're in fourth gear at 1500 rpm and increase the engine speed to 1900 rpm in the same gear, you will increase the speed of the vehicle unless you're spinning the drive wheels.  Lowering the engine speed in the same gear will result in slower speed. 

There's something in what you've said that I'm either missing or not understanding. 

I worked in the petroleum industry. The energy in a gallon of gasoline is independent of octane value. A gallon of 87 octane has the same energy content as a gallon of 93 octane. Higher octane gasoline has a higher ignition temperature which is beneficial to high compression ratio engines. OPE engines are low compression ratio engines along with the majority of automobile engines. If a low compression ratio engine needs high octane gasoline it typically means it is not functioning as originally designed.

Fleetfoot -

OT, but where do you fill up. At the cheapest pump in town or just a decent station that has *good traffic* -- which in theory should = gas that moves in qty and is more fresh. Which might mean better pumps, better maint, filters, etc.

Gas is gas  afaik. Meaning it all comes out of the local pipeline/refinery. How much additive pack differs from brand X versus X when oftentime, it will be some local joe schmoe truck rig filling up the local *top tier* stations.
I'd be inclined to hear some industry folks on what method do you decide to pump your gas...

JoelKlein wrote:

The only way that you could come up with a 400 rpm difference  would be that you are using a a higher gear with the 93 octane.

Yeah, maybe the added engine torque allows running in 5th, at 1500, vs 4th, at 1900, to get acceptable performance (for hills, passing, etc)? That's the only way it makes sense to me.

As a minor aside, Stihl recommends 89+ octane fuel in their engines. Maybe it's different for small, high-revving 2-strokes, vs larger 4-strokes. But at least some OPE recommends gas higher than 87 octane.

Sorry, I was away for a couple hours. here is the story About the high octane: first of all, my dealer recommended NOT LOWER then 89 for the Toro 1028. Maybe he is wrong. I will call up Briggs and ask. I am brand new to OPE. About the Toyota: I reaserched for sooooooooo looooooong about the high octane, the compression, and about the detergent issue. I asked saverel Toyota certified mechanics at the dealers services. The all told me that the ECU will detect the octane level, and will adjust the engine to it. The sequoia/ tondra can be fitted with the TRD high performance kit, which includes bigger fuel injectors, Air Intakes, etc... And then you should use higher octane, becouse the engine is going to compress up to 9:1 instead of the standard 8:1. Now, even without the TRD kit installed, I can In fact stay in a higher gear at the same speed, When i use higher octane. Versus with 87 octane my transmission keeps its self bussy shifting gears up and down. But this is all fine as long as I'm drivIng with the octane in mind... Once I go HARD on the paddal, I'm anyway forcing the transs in to the lower gear... So money in trash... It might be worth trying 89 instead of 92/93. But I'm afraid the gas turnover is much less and not fresh! If any one here feels. That I am wrong, I'm willing to learn. I'm open.

From page 15 of the 1028 owners manual, "Fill the fuel tank with fresh unleaded regular gasoline from a major name-brand service station (Figure 26)." Typically, regular unleaded gasoline has an octane rating of 87 depending on elevation. The detergent level is independent of octane level.

About the detergent level: I'm puzzeled, alot of people says its the same and that is the Law and allot of people say its 87 does have less of it. What I need, is some hard facts!

JoelKlein wrote:
The engine's knock (ping) sensor will monitor how the engine is running, yes. The ECU may try to advance the ignition timing, to produce more power. Higher octane gas will allow the timing to be advanced more, without knocking/pinging. If you run lower octane gas, the ECU will retard the timing to avoid knocking. You might see less power and reduced mileage. I had a car that recommended premium. When premium got to a level that I thought was unreasonable (~$1.80, as I recall. Clearly this was a number of years ago ), I switched back to regular. The engine automatically adjusted, and I could feel that it had a bit less pep, and my mileage dropped a little. But it was still cheaper.

But the engine cannot, so far as I know, change the compression ratio on the fly. The only ways to do that that I can think of would be to change the head, pistons, or maybe the crankshaft. But I don't think the compression ratio can change while you're using it.

There are only a few ways to increase compression ratios in an internal combustion engine.  One decrease the size of the combustion chamber by
1. either using a flat top or dome piston (in place of a dished piston), and or using a set of heads with a smaller combustion chamber.
2 using forced induction such as a turbo or supercharger.

Injectors, air cleaners and headers will do nothing to increase compression ratios.

Higher octane fuels can help hp when the if the  ecu can advance the timing by helping the engine not have pre-ignition or ping thus increasing hp a bit.

Most engines will not see any difference in performance or gas milage using high octane fuel.  In fact a low compression engine (8:1)will probably run worse on high octane gas.