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So, I wanted to bring up this topic to get a better understanding of the gasoline these L24-L28 engines were designed for.

It is my understanding that modern cars today are able to burn various blends of gasoline and ethanol. Older cars are not as well suited. I believe it is a combination of metals used in valves and such and the ability for modern cars to adjust timing to compensate for fuel differences.

I’m not sure when regular gas went away but I think it was in the mid to early 90’s. I had a 66 VW in college in 1990 and could find regular gas everywhere. Then I recall later having to buy lead additives when I still had that car in 2001. It was stolen in 2001, but that’s a different story.

So what fuel were are our Zs designed to use and should we use non-ethanol gas.

This came to mind this morning when reading an article where Biden is going to implement 15% ethanol additive to all summer gasoline. I’ve been able to buy non-ethanol gas where I live because there is a lot of boating here and that’s the preferred fuel for boat engines. I know ethanol attracts water and is harder in seal etc . I know mileage is reduced because ethanol have less energy in a gallon than gasoline. If have to go back to High School chemistry but I believe gasoline is 12 chain carbon and ethanol a 4 chain. More carbon chains equates to more potential energy during combustion.

 

https://www.washingtonexaminer.com/policy/biden-to-reinstate-15-ethanol-gasoline-for-summer-claiming-cost-savings?utm_source=msn&utm_medium=referral&utm_campaign=msn_feed

 

 

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This looks like political commentary.  If you want to talk about fuel, that's cool, but 10% ethanol has been around over many administrations, red and blue.  The guy before didn't roll back the ethanol mandate.  Biden has nothing to do it with it, really.

The supposed reason for ethanol is to create a measure of independence from petroleum suppliers.  A source of non-petro energy.  There is debate about that.  But it's not a red-blue debate.

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I never made a political comment or suggestion it was red or blue issue. Where do you see that in my post? I just said it was an article about adding up to 15% ethanol. I’m actually curious about the effect of ethanol on older engines. Why are you suggesting I’m making a political statement? I honestly don’t care to discuss politics.

I think it’s an interesting topic. The vast majority of people know nothing about fuel what am octane number really means or why places in the mountains having lower octane ratings. I find it generally interesting and really want to know how these modern fuels work with older cars.

The political side of this is a totally different discussion that has no interest to me. Sounds like it interests you?

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You're also confusing ethanol with lead.  Two different things.  The good old days of leaded gasoline, and the corn lobby.

Here's a pretty good summary of what's going on that covers many of the elements.  The AP is, according to previous discussions, a middle of the road news outlet.  One of the most objective.

It's about the corn.

https://apnews.com/article/biden-business-iowa-campaigns-elections-227e09a39aed1680e1f4813334aeae64

 

Members of Congress from both parties also had urged Biden to grant the E15 waiver.

“Homegrown Iowa biofuels provide a quick and clean solution for lowering prices at the pump, and bolstering production would help us become energy independent once again,″ said Iowa Republican Sen. Chuck Grassley. He was among nine Republican and seven Democratic senators from Midwestern states who sent Biden a letter last month urging him to allow year-round E15 sales.

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Posted (edited)

Alright so no politics.

Wasn't the lead added in the fuel to ensure that the softer valve seats would not get beat up by the valve? I recall that on the N42 head that I used in my current build, the valve seats were steel vs the e88 that has some brass/bronze material.

It seems like the lead vs unleaded was accounted for in 75 when the valve seats switched over.

I've not really had any regard for ethanol content since I've gotten my car running, the primary complaint I see is around rubber lines that can't handle the ethanol, but in my limited experience I've yet to see the impact.

Edit*

IIRC modern cars can modify the timing even further by using some type of fuel sensor that detects the ethanol content in the fuel system, but I THINK that would only be to squeeze more performance out of the system as ethanol is a more stable molecule.

Edited by heyitsrama
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Tetraethyl lead's original purpose was as an anti-knock additive.  The protective properties on the valve seats were an unexpected benefit, I think.  It has an interesting history.  The petroleum industry realized early on that the lead emissions were poisonous but pushed it in to the market anyway.  $$$

https://www.britannica.com/science/tetraethyl-lead

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Bottom line, use non-ethanol fuel if it is available in your area.   Where I live, only regular grade has ethanol,  I use the mid grade to avoid the ethanol in the Z cars and the mowers.

FYI, a few years ago, a friend who has 6 or so well sorted S30's had a fuel problem crop up likely from the ethanol gas.  I was working in his garage and noticed the fuel smell, traced it to one of his 280z's, the oem fuel pump body was leaking fuel.  He has since put non-ethanol fuel in his cars.

Another FYI, I recently checked on the cost of the OEM Nissan 280 & ZX fuel pumps out of interest.  They have roughly doubled in price.  (was $235 not long ago).  For this reason alone, the better fuel is worth it.    My non-political 2 cents.  

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Anyway, leaded gasoline and ethanol containing gasoline are two different things.  Different issues.

I am aware these are not the same thing. I was making a general comment of how additives and fuels have changed over the years. We use to add lead, engines were built to use lead back then, then we phased that out for environmental reasons. and Later we began adding ethanol for a different reason but our engines haven’t changed.


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When I put my car back on the road in 2017 after a long nap I cleaned and lined my tank and replaced all rubber fuel lines with E85 rated Gates lines. My carbs were refurbed by Z-Therapy. I contacted them about E fuel and they said they've seen no trouble in their soak testing. I do have access to ethanol free 91 octane so that's what I run and will run as long as I can in my Z and my wife's truck. Many local Maverik's also sell ethanol free 88 octane. I also use the ethanol free for all my yard equipment. One of the big things I notice is how much easier things start when using ethanol free gas.

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I use ethanol free gas too . I’m lucky we have 93 available. I’m not sure what my CR is after shaving my head .020” with flat top pistons on a P79 and I’m using higher octane just to make sure I don’t get pre detonation, probably don’t need it but maybe one day I’ll try the 89.
I have had problems with my power washer and generator when using ethanol gas. As long as I ran it empty it was fine but if I left fuel in the carbs for extended time, they struggled to start. Not sure if it leaves a residue or why but now I always cut off the fuel and let it starve.


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 Engine Masters devoted one episode to low, and high octane fuel as well as E85 fuel while fooling around with timing and boost. The bottom line was the E85 didn't need the expected timing advance as much as expected and E85 produced slightly more power than high octane at high boost. E85 loves high compression ratios.

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52 minutes ago, Av8ferg said:

I use ethanol free gas too . I’m lucky we have 93 available. I’m not sure what my CR is after shaving my head .020” with flat top pistons on a P79 and I’m using higher octane just to make sure I don’t get pre detonation, probably don’t need it but maybe one day I’ll try the 89.
 

Use the Z engine calculator to compute your compression ratio if you really want to know it.

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5 hours ago, Mark Maras said:

 Engine Masters devoted one episode to low, and high octane fuel as well as E85 fuel while fooling around with timing and boost*.

Way cool! I just watched this episode last night!

So the basic takeaway from the episode (as they described it) was that if you engine isn't having detonation issues, then the octane rating of the fuel doesn't matter at all.

The longer story was.... They ran the same engine on a dyno a whole bunch of times running different fuel varieties. They did pulls using 87 pump gas, 91 pump gas, two higher octane race gas varieties (110 and 116 I think?), and then at the end they ran E85. 

They were expecting to have to adjust the timing for the different fuels, but they found that they did not. The engine wanted 29 degrees of advance for every fuel, and made the exact same power (within experimental tolerances) regardless of which fuel they used. The only exception was that the E85 actually made more power than any of the straight up gasoline varieties.

Now... Are any of their findings directly applicable back to our engines? I can come up with a bunch of questions that would need to be answered before I would believe they are, but I'm just in this for the academic entertainment.

 

* One correction to Marks note above... There was no boost. This was all N/A,

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I need to find this TV series you all are talking about.  I found this article, that discusses the problem E85 has with older cars.  Talks about why you need to make some changes when / before using E85 on classic cars and what consequences are.  Carbureted cars seem most at risk, but the the hydroscopic properties of ethanol may effect seals and gaskets on all cars built before mid 80’’s

https://driving.ca/auto-news/news/higher-ethanol-fuel-and-classic-cars-dont-mix

 

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I believe you meant, 'hygroscopic' (ability to absorb water).  No such word as 'hydroscopic' B)

The history of E85 was (and remains) quite politically-driven.  At the start, it seemed like a win-win proposition from the environmental perspective -- an organic, renewable commodity used to reduce exhaust emissions from gas-burning vehicles with not much required in the way modifications to the vehicle.  The corn-growing regions loved it.  Then squabbling started over the diversion of food-production land towards non-food use.  IIRC, other regions got upset over the environmental impact of consuming grassland in their territories for ethanol feedstock.  Now we see ethanol being used to offset embargoed Russian oil stocks.  And on it goes.

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On 4/12/2022 at 5:23 PM, Av8ferg said:

 

So what fuel were are our Zs designed to use and should we use non-ethanol gas.

 

 

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Unleaded 95 ron.  ( You can use higher Ron doesn't really matter this is only to prevent pre ignition )

Ethanol fuel is only for modern cars that are adapted to it. Ethanol eats rubber and corrodes metal in older cars.

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On 4/12/2022 at 1:44 PM, S30Driver said:

Bottom line, use non-ethanol fuel if it is available in your area.   Where I live, only regular grade has ethanol,  I use the mid grade to avoid the ethanol in the Z cars and the mowers...

I had an opportunity to get a close look at some gas pumps being installed a few months ago. With the covers off, I noticed there were only two supply lines for the gasoline side of the pump. I asked about it and was told they mix regular and premium at the pump to make mid grade. Indeed, another station confirmed they only have two fuel storage tanks. I don't know if this practice is pervasive (I'm in the SE US). But if so, mid grade has some ethanol in it.

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18 minutes ago, the_tool_man said:

I had an opportunity to get a close look at some gas pumps being installed a few months ago. With the covers off, I noticed there were only two supply lines for the gasoline side of the pump. I asked about it and was told they mix regular and premium at the pump to make mid grade. Indeed, another station confirmed they only have two fuel storage tanks. I don't know if this practice is pervasive (I'm in the SE US). But if so, mid grade has some ethanol in it.

You are correct. Mid-grade is typically a blend of premium and regular.

I am fortunate enough to live near a boating area so I can get 90 ethanol free or 87 ethanol free. I can even get 110 at a pump about 10 miles from my house.

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You never really know what you're getting at the typical pump.  Today's cars are designed to adjust to the variation.  

https://www.fueleconomy.gov/feg/factors.shtml

"Some fuels contain less energy than others.

Using oxygenated fuels or reformulated gasoline (RFG), for example, can cause a small decrease (1%–3%) in fuel economy.

Most of the gasoline now sold has a small amount of ethanol in it—up to 10% by volume depending upon the region. Using gasoline with 10% ethanol decreases fuel economy by 3%–4%.

The energy content of gasoline varies seasonally. Typical summer conventional gasoline contains about 1.7% more energy than typical winter conventional gasoline."

 

 

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