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R36 Member
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Discussion Starter · #1 ·
Does any shop build in an extra limp mode or have the ability to lock out the engine start if low octane fuel is accidentally introduced to the tank/system? I ask because, for those investing so much in their cars (and even the amount required to simply buy a GT-R is nothing to sneeze at) it would be nice to be able to avoid potential knock damage from the wife/family/friend accidentally putting stuff less than 91 US octane in the tank.

Does this exist, and if it does, who offers this system? I'm assuming that there isn't a factory lockout/panic-tune system in place.
 

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R36 Member
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Discussion Starter · #4 ·
If the car is stock, detects excessive knock, it will put boost back to spring pressure.

When you try hard enough, you blow anything up. The price you pay.
does that mean that 87 oct in the usa can or cannot idle in something like the gtr? i mean, it's a relatively easy mistake to make, especially if you happen to let your significant other (who may not be the enthusiast that you are) drive your cars.
 

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GTR Nerd
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does that mean that 87 oct in the usa can or cannot idle in something like the gtr? i mean, it's a relatively easy mistake to make, especially if you happen to let your significant other (who may not be the enthusiast that you are) drive your cars.
That is the price you pay for letting someone use the car that doesn't know the car. It is labeled premium fuel only in the dash, on the fuel door. If they don't do it, then they should be liable for it.

Again its the price you pay if you let someone use your toy without the proper training. The GT-R is a 480-545hp weapon that should not be in the wrong hands.

The car will run fine on 87 if you don't boost, I run my M45 on it all the time, knocks like a mo-fo but I don't care. If it breaks, I will throw it in the gutter, and go buy another.

The GT-R will rattle, you will hear it. If it rattles that hard and spits a rod, then it does.
 

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R36 Member
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Discussion Starter · #6 ·
That is the price you pay for letting someone use the car that doesn't know the car. It is labeled premium fuel only in the dash, on the fuel door. If they don't do it, then they should be liable for it.

Again its the price you pay if you let someone use your toy without the proper training. The GT-R is a 480-545hp weapon that should not be in the wrong hands.

The car will run fine on 87 if you don't boost, I run my M45 on it all the time, knocks like a mo-fo but I don't care. If it breaks, I will throw it in the gutter, and go buy another.

The GT-R will rattle, you will hear it. If it rattles that hard and spits a rod, then it does.
I mean, this hasn't happened to me, but I feel like low octane fuel safety is a no-brainer kind of feature for something in such a premium price range, especially if it's achievable through electronic measures to control compression. So are you saying it's possible to implement, or no?
 

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I mean, this hasn't happened to me, but I feel like low octane fuel safety is a no-brainer kind of feature for something in such a premium price range, especially if it's achievable through electronic measures to control compression. So are you saying it's possible to implement, or no?
No its not possible. It can retard timing to a certain degree, it can knock back boost. You can't control compression ratio.

The car is labeled premium fuel only. If someone doesn't know what that means, they shouldn't be using the car. If they are using the car, they should have the basic understanding of knock, and if they hear it, they should investigate it.

If they are incapable of this, then stick them in a Camry.
 

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R36 Member
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Discussion Starter · #8 ·
No its not possible. It can retard timing to a certain degree, it can knock back boost. You can't control compression ratio.

The car is labeled premium fuel only. If someone doesn't know what that means, they shouldn't be using the car. If they are using the car, they should have the basic understanding of knock, and if they hear it, they should investigate it.

If they are incapable of this, then stick them in a Camry.
is there not at least some way to get the ECU to lock out the starter if the wrong fuel is detected?
 

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Theoretically some tolerance is possible. The stock ECU does make some adjustments for knock. I don't know if that aspect of the stock ECU is being utilized in tuned setups (someone chime in if it is) but what Sean is saying is this: Even if it is done, there are limits to what the car can take. If your family/friends put octane that's low enough in the car, then drive the car hard enough, bad things will happen.

Also, and to Sean's point, the GT-R is a serious car. If you have someone who is eager to drive the GT-R "fast" but unable (read:unwilling) to take the time to ensure they are fueling properly, you might have other things to worry about than the motor.

That said, from a product design standpoint the above is irrelevant and I do agree with you. As it is, I believe the closest you might be able to do is a map designed for low octane. But I would still recommend a serious conversation at a minimum. Because even with a map that can take a lower octane, they might manage to feed it diesel or something else.
 

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R36 Member
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Discussion Starter · #11 ·
No, it can not test the fuel.
electrochemical principles applied to voltage metering could ostensibly be used. i realize this is independent of the ECU in and of itself, but I feel like this is something that is worth implementing, given that it doesn't false-positive and brick your car randomly. from a product design standpoint, think about it: a premium fuel car that can't be damaged by low octane fuel! it should be standard in the future, IMHO.
 

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Do you have a reference on how "electrochemical priciples" can be used to determine fuel octane? Sounds like an interesting read. Lots out there on sensors that can determine the amount of ethanol in fuel on the fly (GM FlexFuel, ProEFI, etc.) but never anything that can determine octane (aside from just monitoring knock which is likely "too late" for extreme variations in octane from the manufacturers recommendations).
 

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That is the price you pay for letting someone use the car that doesn't know the car. It is labeled premium fuel only in the dash, on the fuel door. If they don't do it, then they should be liable for it.

Again its the price you pay if you let someone use your toy without the proper training. The GT-R is a 480-545hp weapon that should not be in the wrong hands.

The car will run fine on 87 if you don't boost, I run my M45 on it all the time, knocks like a mo-fo but I don't care. If it breaks, I will throw it in the gutter, and go buy another.

The GT-R will rattle, you will hear it. If it rattles that hard and spits a rod, then it does.
Love the Easy E quote!!
 

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R36 Member
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Discussion Starter · #14 ·
Do you have a reference on how "electrochemical priciples" can be used to determine fuel octane? Sounds like an interesting read. Lots out there on sensors that can determine the amount of ethanol in fuel on the fly (GM FlexFuel, ProEFI, etc.) but never anything that can determine octane (aside from just monitoring knock which is likely "too late" for extreme variations in octane from the manufacturers recommendations).
I'm interpolating with my knowledge of a new development in neurochemistry that is basically using microelectrodes and has been able to detect the exocytosis of single vesicles based on pretty much nothing more than an understanding of how the chemical characteristics of fluid media affects voltage characteristics (Mark Wightman). That's pretty damned sensitive. With "octane level" being a chemically significant trait, it should be trivial to introduce similar systems (and no, for anyone out there wondering, voltmeters don't pass current so you're not going to be blowing up your gas tank with this) without that much modification in overall design, barring anomalies in results, of course.
 

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I'm interpolating with my knowledge of a new development in neurochemistry that is basically using microelectrodes and has been able to detect the exocytosis of single vesicles based on pretty much nothing more than an understanding of how the chemical characteristics of fluid media affects voltage characteristics (Mark Wightman). That's pretty damned sensitive. With "octane level" being a chemically significant trait, it should be trivial to introduce similar systems (and no, for anyone out there wondering, voltmeters don't pass current so you're not going to be blowing up your gas tank with this) without that much modification in overall design, barring anomalies in results, of course.
So add a dummy proof system to an already expensive car for something that can be prevented by not being stupid that adds next to no value? If you drive a GT-R and you're worried about gas prices you should re-examine purchasing the car. Since it's trivial to implement the system why not use your own R35, if you even have one, for development and report back how it goes.
 

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R36 Member
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Discussion Starter · #16 ·
So add a dummy proof system to an already expensive car for something that can be prevented by not being stupid that adds next to no value? If you drive a GT-R and you're worried about gas prices you should re-examine purchasing the car. Since it's trivial to implement the system why not use your own R35, if you even have one, for development and report back how it goes.
Did I say trivial to "implement?" No. Also, don't you have insurance on expensive items in your house? Isn't damage to those items "prevented by not being stupid?" You're missing my point. This is a safeguard for those situations, no matter how unlikely the situation. Don't need to insult a guy who just happens to want guarantees on things like not having my engine knock itself to pieces because somehow inappropriate fuel was introduced to the tank. It's just like having a sprinkler system for the times that somehow you light something in your house/building on fire.

Also, you underestimate the idiocy of humanity, man... and count me in if you want - i'll still prefer having a bad-gas safety on any car that i care a lot about.

tl;dr think about it: would you rather have a "YOU PUT 87 IN THE MOTHE*******ING CAR?!" situation, or a "oh, PLEASE never do that again, but you know the car keeps from running so it doesn't blow itself up" situation?
 

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Simple....

#1 it is a valid thought, for 87 could be introduced without driver error--- ie bad gas station..

#2 If your boost gauge flashes, don't drive WOT... Nothing will happen to the engine under vacuum...
 

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R36 Member
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Discussion Starter · #18 ·
Simple....

#1 it is a valid thought, for 87 could be introduced without driver error--- ie bad gas station..

#2 If your boost gauge flashes, don't drive WOT... Nothing will happen to the engine under vacuum...
#1 thank you... I wanted to say that but didn't want to get flamed by haters because bad gas is relatively rare.

#2 is the mechanical compression ratio low enough to avoid detonation in the GTR?
 

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Also, you underestimate the idiocy of humanity, man... and count me in if you want - i'll still prefer having a bad-gas safety on any car that i care a lot about.

tl;dr think about it: would you rather have a "YOU PUT 87 IN THE MOTHE*******ING CAR?!" situation, or a "oh, PLEASE never do that again, but you know the car keeps from running so it doesn't blow itself up" situation?
You're in the same situation regardless: the gas is still in your gas tank. Your car will tell you that is going on through knocking, either drain the tank and throw it in your beater or dont boost. When I fill my tank I'm anal retentive that I only use premium gas from top tier suppliers (http://www.toptierga.../retailers.html). Anyone that I give the keys to has the same anal habits and have always asked "where do you get gas at" because they get crazy about the same stuff. There is no cure for human stupidity.

I've never encountered or heard of a situation where someone has gone to a top tier gas station, put in 93 and gotten 87. I have heard of water in gas being a problem but never the wrong octane levels. Maybe I'm spoiled on the east coast.

For my own sake, are these legitimate concerns for the car you actually own or are you speaking for the GT-R community? It's not something I'm worried about...
 
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