My car... 444444...

[Smart_Guy]

I'll share what I learned thru extensive research the past couple or years. Please correct me if I'm wrong.

Mine runs around the 180 range as well. Mine has a 305 or 5.0 liter. It has a good Torque curve of around 300+ pound of torque around 2800 rpm. That is running 87 octane. Add around 30 hp and another 60 ft. pds of torque on high test, 91 octane. the motor has some mods done to it so those readings are guess as i don't have any way of testing. I can tell you i do feel gains. When i get up to it i plan to rebuild this motor to even Better specs. When i do that i should have around 230 - 250 hp and around 380- 400 ft pds of torque. That difference of heads and tbi upgrades and other goodies added. like the 350cu.in torque cam and roller lifters and roller rockers. Will reuse them again. Main difference is the heads and pistons. May have to put a new crank in as well. Once that is done i should have a real screamer of a motor.

That's a V8, right? If so, that's why it has high displacement and high torque. Those two are also the reasons why it can give 180 HP on 87 octane (low grade). High octane is mainly for high output engines to give max power. Basically, higher output on smaller engines means the need for higher octane to better reach the high output the engine is designed for.

For the sake of clarification:
My car's engine gives 180 HP max in its 3 liters displacement.
Your car's engine gives 180 HP max in its 5 liters displacement.

For mine, the small engine requires high octane to reach that much power but with yours the engine is big enough to easily work so it does not have to use high octane for such output.

Think of it like this: a huge man can naturally lift a weight without so much effort but a small man could lift similar weight but will have to push hard to manage to because he's not naturally big to have natural lifting power.

If we compare mainstream German V8's of the 80's, as an example of old cars, with mainstream American V8's of the same era, we will find that the Germans have like 260-300 HP but the Americans have ~150-210 HP. The Germans will require 91 octane gas minimum to reach that power while the Americans require 87 octane minimum.

I can't tell you how much power they added but it sure run good. Better gas is better for the engine because they run cooler and treats it better timing wise. My Taurus is made to run on 87 as normal but capable of E85 to high test.

Did you know that the higher the octane the slower it burn?

Yes. Octane is to control how fast gas burns. Engines with high output in relation to their size work hard, so lower octane will burn faster and cause knocking; burning at the wrong time. That's bad for the engine. If there's a knock sensor, the spark timing will be reduced to prevent that but the output will be reduced too.

 

[Celery]

Reason we have different grades of gas is the compression ratios of the engines. High compression needs high octane to control the rate of burn. Putting 87 octane in an engine with 10.5 ratio will make the engine knock like crazy.

3L V6 and 5L V8 doesn't dictate what grade gas to use, it's the compression ratios that do. My car runs better on 93 though it's made for 87 because of the ECU setting the ignition timing and fuel ratio for optimal performance.

 

[Sid]

100F? We get that now in the end of October. Most of the year we get +104F. 113F is a normal occurrence here in that most of the year part too. Putting 150k miles here could equal putting 270k miles where you live on the same due to the heat

But, SG, since internal combustion engines operate best when at a running temperature twice what you experience in SA, shouldn't they, instead, be "happy" to start out cold at 100+?

Sid

 

[Smart_Guy]

But, SG, since internal combustion engines operate best when at a running temperature twice what you experience in SA, shouldn't they, instead, be "happy" to start out cold at 100+?

Sid

Yes, that's true. What I believe is that the thermostat is responsible to bring the engine to the high temperature it "internally" runs best with, then the cooling system prevents it from going so high, not to have the surrounding burning so hot. Engines, as you know, have many other parts other than the internal combustion parts that ambient temperatures affect too. Basically, internal combustion heat stays internal for the most part.

I believe moderate weather is the best for the engine to run and live. I was optimistic when I said +104F. We do get +115F often and I do drive in that temperature much. Cooling system parts work overtime

The thing that I conclude out of all that is that being happy to start and run for the engine; e.g. best performance and gas consumption, is different than longer in mileage to live; e.g. longer living head gasket and valves guides and stem seals.

I of course could be wrong in this. I noticed that in colder weather (not freezing, just colder as in not burning like here) car batteries live +5 years while where I live 3 years is the best they can get.

Do you mean that besides operating best, the engine also lives longer? I don't disagree with you if you say yes even I seem to don't necessarily agree with you.

 

[Smart_Guy]

See something weird?

Yeah, the other day I found that the front right signal light was missing. What the?!?! Long story short, I can't get the part until after like two weeks from now due to the end of the fasting month and the holiday after it where it gets crazy every where. I then remembered that when I had the accident and changed to the smoked ones, the right amber one was fine and I kept it in the trunk! Keeping some parts at hand could save some trouble. This time tho it saved the function but the looks got weird. That's no real problem for me on the short run.

 

[Wallaby Dan]

Well, Smart guy, I had to break down and spend bucks on a pair of headlights. Not to bad for the price but still had to. Both of mine were leaking and i don't have headlights right now. Both started leaking water and all four lights are burned out. The water just shatters the bulbs in them.

 

[Smart_Guy]

As in leaking water inside causing the hot bulbs to go boom or short?



It's okay, WD. That's a good investment on the car anyway. Headlights don't live for ever, but live so long and they are important after dark. Not to mention the better performance due to clarity (old ones kinda get foggy) and the shiny new look

I remember when I replaced the +18 year old headlights seven years ago. Even tho they still had some life in them (but lost so must performance and I drive so much at night), it made day and night difference in everything... including my pocket, yeah

 

[Celery]

I think WD's headlight is a bulb rather than a sealed beam.

 

[Smart_Guy]

Hmm... aren't bulbs also protected by a housing and a lens; i.e. the whole assembly the headlight? My car uses bulbs too in the headlights?

Are you referring to the projector vs. the reflector types?

 

[Celery]

Yes it is. The assembly is a permanent part of the car and the bulb is replaceable. The sealed beam is the whole unit that's replaceable. That would be the new shiny part.