I have read on other forums that raising the compression ratio(not a lot) on a engine can help with fuel economy. Does any one know if this would help achieve better fuel economy?
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I have read on other forums that raising the compression ratio(not a lot) on a engine can help with fuel economy. Does any one know if this would help achieve better fuel economy?
prolly not a whole lot and once you start raising the ratio you have to start using better gas so its a loose loose situation lolQuote:
Originally Posted by oline897
If you do the right things, you can get better gas milege with higher octane gas. My sammy got 18mpg on 87, and 20mpg on 89. Increasing compression would require a higher octane fuel to prevent ping, and also to get the more efficient "bang".
Cars that get really good mpg always have high CRs. The celica gts has what, 11.5:1? But, you can tune your motor to run with higher dynamic compression without changing your static cr. That's not a trick answer either.
What is the stock compression af the a20?
9.3:1
On 87 octane you can run what, about 10.5:1??
89 is high octane? o.O
The lowest octane we got over here is 95...
well lucky you in finland lol i know in cali its reg85 plus87 prem89 i thinkQuote:
Originally Posted by Naf's Asdf
maybe in cali...everywhere else its reg 87 octane, prem 89, and super is 91
Over here it's all 95 and 98, some places got 99 too...
But also the price we pay for it is getting ridiculous...
Our plus is 89 and our premium is 93
for fuel economy get good spark pugs, air filter, new wires, MSD blaster coil and seafoam your car.
yeah, i really dont think you will come out on top with a cylinder head resuface. i wouldnt recommend it if you dont have a blow head gasket. or if your combustion chamber is full of carbon deposits on the valves, maybe then you would improve with taking the head off. but unless you really need to dont do it.
dont know how many miles you've got on your car. i would recommend chaning the timing belt if it hasnt been already (preventative maintancene), change your distributor cap and rotor, spark plugs and wires, adjust the valves, and run some good fuel cleaner through the fuel tank a few times. maybe some cleaner like barryman B12 or Seafoam. while your at it take a look at your coolant. if its rusty or brown, change that out too along with any belts or hoses that look old or worn. this is more of a manitancene thing, not so much for fuel economy. but will be a great improvement on your car's reliability status.
1. Maintain your car.
2. Seafoam is useless.
Yeah, airflow improvements and runner length tuning can improve your dynamic compression ratio, but by flowing more air, you need to add more fuel. So how exactly does this help mileage?Quote:
Originally Posted by Accordtheory
The whole point of this discussion, I believe, was how to get more power out of an existing amount of fuel/air, thus requiring less of it, not burning more of it for more power.
I don't think shaving your head will do much good unless you've got a convertible. The air is already pretty stirred up when you put your windows down, and I don't think that it would flow smoothly over your head anyways. Maybe if you had an S2000. I bet a motorcycle helmet would be far more aerodynamic, plus you wouldn't need a haircut. The gas mileage effects would still be minimal.
The US uses (RON + MON) / 2. I believe the rest of the world uses usually RON or MON, one of which is higher than the US method, so it's really the same. Your 95 is probably the same as our 87.Quote:
Originally Posted by Naf's Asdf
+1. 310,000 miles with a Weber carb and still getting 28-32mpg depending on my driving without ever doing any "cleaning." Run your engine hard once in a while and it will keep itself as clean as it needs to be.Quote:
Originally Posted by guyhatesmycar
Almost, but not quite... Atleast if wikipedia has got it right.Quote:
Originally Posted by 2ndGenGuy
Quote:
In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).
seafoam is good for something. thinning your oil and freeing up deposits so your car can smoke out the tail pipe. haha! i sell bunches of that shit. too expensive IMO, for what it does and doesnt do. some people live by that stuff though. but i dont use it, just sell it.
We put Seafoam in our Sidekick and it put carbon in the #4 exhaust valve... Big hole...
It works that good! lol...
I spread a can in mine and I know my car is "Happier" than when I got it, but it wasn't HP in a can.
Never used Seafoam, but I've read enough horror stories never to want to. If you use good gas (ie: Chevron 91 octane) you won't ever need Seafoam.
I used it on my car a little bit after I got it in an attempt to help emissions testing. I did test better afterwards and the car ran a little better, but it still didn't pass. That was due to a bad catalytic converter though. lol. Oddly enough the car passed at 2500 rpm without the cat. hmm.
