Driving cars at full throttle

[Slash]

Like I said, the car has 200k miles on it. Motor is a bit tired, but the car is in exceptional shape. He got it for $2k.

I don't think it's that bad. It was running quicker than a few of the GTP's that tend to show up, and when we talked to their owners, the best they got was around a 9.8/mid 15 as well.

And as I said previously, he runs premo now.

 

[velly]

I use WOT a few times every day in my 91 mk2 Golf GTI
But you will find about 3/4 throttle IS full throttle on most cars
Does it damage your engine...no
allowing you car / truck to rev up on the rev limiter for prolonged times aint the best thing to do (you can do this on part throttle, doesnt have to be wide open)
Allowing the engine to rev wont kill it, I work for a Vehicle manufacter and The china market will not rev about 3000rpm as they think it will distroy the engine (even on car with a 7000rpm rev limit) It is hard to design a car to drive smooth and perform with a 1.3L 4 cylinder engine and not allowing it to rev high. (because that is the customer will drive the car)

 

[White & Nerdy]

Since there was a discussion of fuel octane here, does anyone have any idea at all why "premium" varies from state to state? Up here it's only 90 octane, which is stupid since a great number of cars need 91-92 to produce full power, and many older muscle cars need 94+ to run right from what I've heard.

 

[Aquarelle]

Since there was a discussion of fuel octane here, does anyone have any idea at all why "premium" varies from state to state? Up here it's only 90 octane, which is stupid since a great number of cars need 91-92 to produce full power, and many older muscle cars need 94+ to run right from what I've heard.

Usually it's to do with altitude and emissions depending on the state, in higher elevation states you don't need a higher octane and because of the extra refining required to create higher octane some states use lower octane to reduce emissions (California for instance).

 

[Slash]

Since there was a discussion of fuel octane here, does anyone have any idea at all why "premium" varies from state to state? Up here it's only 90 octane, which is stupid since a great number of cars need 91-92 to produce full power, and many older muscle cars need 94+ to run right from what I've heard.

I always wonder that as well. You can get 87, 89, 91 and 93 here. Anything higher, and you need to go to the airport.

Only some muscle cars need 94 or higher. Most old engines will run on 87 with 10:1 compression or less (most are) but need hardened valve seats so they can run without leaded fuel. It's not very common to find a factory muscle car motor higher than 10.5:1, which is what a lot of cars run on these days actually. Those run on 87 fine, but are designed for it. There are old stock motors than run as high as 12.5:1 though. That requires around 98. I know of a few guys than run 14:1 and run on NASCAR type 106 octane Sunoco gas aka jet fuel. We used to get 50 gallon barrels of 117 from the airport to run our old motor. But that was how you made power back then. High compression and high displacement. And the fuel was ironically known as high-test.

 

[TouringBubble]

Yeah, you can run 10:1 with low timing and be fine on 87. Crank up the timing and its a different story.

Leaner mix
Higher compression
Advanced timing
Higher boost

These all require higher octane to keep knock at bay.

Its important to note that older cars designed for leaded fuel dont use the same octane in unleaded. Lead is a knock preventer in fuel. I believe that octane was calculated differently back in those days.

Basically, if the car asks for 91, and you plan to go past half throttle at any point ... Put 91 in it. If not, you are likely knocking and losing power at best ... Breaking things at worst.

 

[White & Nerdy]

One thing that is worth mentioning: That Corvette I borrowed last year ran fine on 90, though I didn't have access to a dynamometer to see if it was making full power.

The guy I borrowed it from seemed to be putting 87 in it, because it was running really bad at first.

Also pro-tip. The brand of gasoline seems to make at least some difference. If you're ever in Alaska, don't buy from Tesoro unless you can't help it. They're known across the state for selling bad gasoline, and my car seems to run a lot better on Chevron than on Tesoro. Tesoro is a few cents cheaper a gallon, but if it makes your car run a few dollars worse I'm not sure it's worth it. I don't have any experience with Holiday, Shell, or Essential One.

 

[Zenith]

I was told by a professional in the petroleum engineering sector that all the oil and gas is exactly the same between gasoline retailers. The same oil from the same holes in the ground through the same pipes into the same refineries using the same methods.

When discussing topics like this it is important to distinguish sources between people who know how engines work and people who have a morsel of experience that they believe translates into wisdom.

Especially ones who claim to have been aircraft designers, then auto testers yet for some reason choose to use a Mk2 Golf as a sole source of proof...

 

[Harry6784]

I was told by a professional in the petroleum engineering sector that all the oil and gas is exactly the same between gasoline retailers. The same oil from the same holes in the ground through the same pipes into the same refineries using the same methods.

When discussing topics like this it is important to distinguish sources between people who know how engines work and people who have a morsel of experience that they believe translates into wisdom.

Correct but each gas station uses different additives. Example; Shell's 'V-Power' is not the same liquid that goes into your gas tank as 'Chevron w/Techron'.

 

[White & Nerdy]

Maybe they don't seal their tanks right and water leaks in then, I don't know. All I know is, my car doesn't run as well on Tesoro's gas (to the point where it may try to choke out when revved above about 2K if not given time to warm up first) and apparently this is pretty common knowledge up here.

Also, then, what about all the additives and blends advertised by different brands i.e. Chevron Techron, Shell Nitrogen Enriched, etc.?

 

[Slash]

Yeah, you can run 10:1 with low timing and be fine on 87. Crank up the timing and its a different story.

Leaner mix
Higher compression
Advanced timing
Higher boost

These all require higher octane to keep knock at bay.

Its important to note that older cars designed for leaded fuel dont use the same octane in unleaded. Lead is a knock preventer in fuel. I believe that octane was calculated differently back in those days.

Basically, if the car asks for 91, and you plan to go past half throttle at any point ... Put 91 in it. If not, you are likely knocking and losing power at best ... Breaking things at worst.

You forget to mention baseline mechanical timing in the first place, that makes the rest of it possible.

Lead is a knock preventer and it was also used as internal lubrication, hence why valve seats need to be hardened to run on unleaded.

 

[TouringBubble]

Timing is timing. The more advanced the spark, no matter if mechanical, electronic, or a combination ... the closer the peak cylinder gets to the minimum best torque point. This is the point where the engine will make the most torque possible, but is also increases the chance of knock.

 

[Slash]

There is different types of timing. Engine timing, ignition timing etc. if your mechanical timing has too much slack it won't run worth a damn. I learned the hard way.

 

[savage388]

I played around for a while with different brands of gas using different additives in my old trans am, the carb was pretty finicky with different brands of gas, for example it would never cold start on the local discount gas brands and ran like garbage Sunoco. I can say the

Maybe they don't seal their tanks right and water leaks in then, I don't know. All I know is, my car doesn't run as well on Tesoro's gas (to the point where it may try to choke out when revved above about 2K if not given time to warm up first) and apparently this is pretty common knowledge up here.

Also, then, what about all the additives and blends advertised by different brands i.e. Chevron Techron, Shell Nitrogen Enriched, etc.?

additives make a huge difference.

 

[Slash]

I hate having additives in my gas other than when we used to have to add lead. We used high end Sunoco stuff when it was actually good. Now we just use whatever we can afford. Luckily, there's a few places that sell ethanol free gas around here.

Never had problems starting it though, with anything. What carb was on that 383? Edelbrock right?

 

[ZHPbimmer]

Very rarely do I ever go full throttle, and even more rarely do I slam it from first to second. Actually, within the two years of driving my car I have only once flat out floored it from first to second.

I do however, give it 50-75% throttle on a daily basis.

 

[TomatoFK]

One time I was in a hurry in my 07 RAV4 (with regular maintenance) on highway, I stayed at around 3000rpm, reached to 5000rpm+ a few times to pass the traffic, and after around 20mins the engine light, 4WD light, and VSC light came on flashing together, its like the car did not like it, so I had to cruise for a while and everything went back to normal after 10 secs. But who knows, since I live in a place where the quality of gasoline is not always trust-worthy.

 

[Slash]

I would have toyed with it some more to see if it came back on.

Anyways, if an engine wasnt meant to be driven at WOT at some point in its life, they would be limited to a max certain throttle position with the RPMs limited to very low.

 

[jetrp1]

I drive my '96 Legacy at full throttle a lot to merge into traffic. Its got 380k miles so no effect on durability.

i drive my '95 silverado at wide open all the time, still running strong (203500 Miles on the odometer)

 

[TexRex]

i drive my '95 silverado at wide open all the time, still running strong (203500 Miles on the odometer)

And you resurrect a thread that's been inactive for literally four years to tell random people that as your very first post?