Fuel injector cleaner
10-22-2018, 09:52 AM
#61
Race Director
Not defending the use of 87 octane as I would not use it BUT if you "never" put your foot past half throttle, especially important at lower rpm, the 91 or 93 octane is not needed!
However if you do use 87 octane, one of the many knock sensors will detect a "knock" (preignition) and the computer will retard timing and probably richen the air/fuel mixture in attempt to eliminate it! As the owner's manual states that will reduce max power and reduce mpg. The high octane rating is needed when cylinder pressures are near max based on the compression ratio. At part throttle, the air/fuel mixture does not reach max pressure on the compression stroke and therefore won't preignite or "knock." It's like having a lower compression engine. Unlike a diesel, combustion will (should) occur only when the spark plug fires.
Once the computer sets the timing back and/or richens the air/fuel mixture you're not only loosing max power your getting less mpg! Defeating the $/gallon savings you thought you were getting. Perhaps at every start it looks for a knock sensor signal- don't know. New engines have many knock sensors so doubt you'll hear a knock before it does it's reduced timing etc thing!
SIDE BAR
The statement, "if you hear knocking" remines me of a friend who had a high performance car and traveled to Mexico were he filled up and the car knocked so bad no matter how he drove he was worried he was damaging the engine and probably was. Timing and rich air/fuel ratios can only help so much then it will knock!
Also recall some years ago when my communications manager and good friend got a great deal on a new Olds and when he got it home realized it said use only high test gas. It came with a turbocharger! He said he refused to pay for high test gas so always used regular. Told him the same, just never use more than half throttle! He was not an aggressive driver and probably never did. He had the car for many years and all was fine. Particularly with a turbo charger the max octane requirement is needed when on boost.
However if you do use 87 octane, one of the many knock sensors will detect a "knock" (preignition) and the computer will retard timing and probably richen the air/fuel mixture in attempt to eliminate it! As the owner's manual states that will reduce max power and reduce mpg. The high octane rating is needed when cylinder pressures are near max based on the compression ratio. At part throttle, the air/fuel mixture does not reach max pressure on the compression stroke and therefore won't preignite or "knock." It's like having a lower compression engine. Unlike a diesel, combustion will (should) occur only when the spark plug fires.
Once the computer sets the timing back and/or richens the air/fuel mixture you're not only loosing max power your getting less mpg! Defeating the $/gallon savings you thought you were getting. Perhaps at every start it looks for a knock sensor signal- don't know. New engines have many knock sensors so doubt you'll hear a knock before it does it's reduced timing etc thing!
SIDE BAR
The statement, "if you hear knocking" remines me of a friend who had a high performance car and traveled to Mexico were he filled up and the car knocked so bad no matter how he drove he was worried he was damaging the engine and probably was. Timing and rich air/fuel ratios can only help so much then it will knock!
Also recall some years ago when my communications manager and good friend got a great deal on a new Olds and when he got it home realized it said use only high test gas. It came with a turbocharger! He said he refused to pay for high test gas so always used regular. Told him the same, just never use more than half throttle! He was not an aggressive driver and probably never did. He had the car for many years and all was fine. Particularly with a turbo charger the max octane requirement is needed when on boost.
Yes I know I could go figure it out for myself but you probably know off the top of your head ...
10-22-2018, 10:02 AM
#62
Race Director
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11.5 to 1 and that's incredible.
10-22-2018, 10:07 AM
#63
Race Director
10-22-2018, 10:10 AM
#64
Race Director
Exactly! If Joe thinks he's going to get long engine life running 87 octane in the heat of Texas, combined with only doing 25,000 mile oil changes, he's sorely mistaken.
10-22-2018, 11:23 AM
#65
E-Ray, 3LZ, ZER, LIFT
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Yep aluminum heads, DI and carefully designed chamber swirl have been great engineering! To think in 1974 the max power in a Vette 350 small block was 250 hp. The max 454 cid was 270 hp!.
Last edited by JerryU; 10-22-2018 at 11:24 AM.
11-10-2018, 01:14 AM
#66
Well, it's misbehaving again, but still following the pattern I described up thread. I filled up, drove 30 miles, crapped out, let it run down (never started registering though), filled up, then twenty miles later it worked again. CEL hasn't cleared up yet, but I got home before that was expected. We'll see in the next few ignition cycles.
The crappy part, now is not the sensor, but MD VEIP, and I need to have it inspected before 12 Dec. Now, it's a balancing act, once the CEL clears, and how long before VEIP can run a clear OBD test, and it craps out again, because, now I don't ever think it will be truly fixed.
It was behaving for two thousand miles and then this. I honestly don't know what to think.
I thought I had it fixed.
The really odd part is that even though the DIC shows "- - -" for range while the needle is pegged at zero, the my Chevrolet app will still give an accurate fuel gauge range. I have no idea where it's getting it's info, but it has been accurate, and yes, I have pinged it a lot while it's been misbehaving, and every single time, it has tracked it very accurately.
The crappy part, now is not the sensor, but MD VEIP, and I need to have it inspected before 12 Dec. Now, it's a balancing act, once the CEL clears, and how long before VEIP can run a clear OBD test, and it craps out again, because, now I don't ever think it will be truly fixed.
It was behaving for two thousand miles and then this. I honestly don't know what to think.
I thought I had it fixed.The really odd part is that even though the DIC shows "- - -" for range while the needle is pegged at zero, the my Chevrolet app will still give an accurate fuel gauge range. I have no idea where it's getting it's info, but it has been accurate, and yes, I have pinged it a lot while it's been misbehaving, and every single time, it has tracked it very accurately.
11-10-2018, 02:05 AM
#67
E-Ray, 3LZ, ZER, LIFT
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^^^
No current thoughts on the mystery BUT when I installed a lower temp thermostat in my modified S10 it would trip a cell on really cold days and the check engine light would stay on. I used my OBDII monitor to reset the CEL and it would stay off until the next really cold day. I'd repeat the OSBII reset until our ~two cold months were over!
Might help you get past inspection!
No current thoughts on the mystery BUT when I installed a lower temp thermostat in my modified S10 it would trip a cell on really cold days and the check engine light would stay on. I used my OBDII monitor to reset the CEL and it would stay off until the next really cold day. I'd repeat the OSBII reset until our ~two cold months were over!
Might help you get past inspection!
Last edited by JerryU; 11-10-2018 at 02:07 AM.
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owc6 (11-10-2018)
11-10-2018, 03:20 AM
#68
Please show me where it is Recommended. No where does it say 87 is recommended. It does say it can be used. That is not the same as recommended. Try reading comprehension. Read the manual below. Does not say 87 is recommended. In fact it warns the 87 will have reduced acceleration.
Page 206 of the 2018 manual states exactly this, as it is copied right out of the PDF manual.
The bold is what they recommend you use for best economy and performance.
The Red can be used, but it will lead to reduced acceleration and fuel economy.
So why would some one buy a High performance car, and be satisfied with not getting the best performance by using a 87 octane fuel?
Sad some one will spend 60K or so on a performance car, and not want the best performance.
Page 206 of the 2018 manual states exactly this, as it is copied right out of the PDF manual.
The bold is what they recommend you use for best economy and performance.
The Red can be used, but it will lead to reduced acceleration and fuel economy.
So why would some one buy a High performance car, and be satisfied with not getting the best performance by using a 87 octane fuel?
Sad some one will spend 60K or so on a performance car, and not want the best performance.
Last edited by Skid Row Joe; 11-10-2018 at 04:26 AM.
11-10-2018, 03:26 AM
#69
Approved and recommended are one in the same. As used in the 2017 Owners Manual. What do you think the difference is?
11-10-2018, 07:49 AM
#70
Race Director
11-10-2018, 07:52 AM
#71
Le Mans Master
Let me know if you wanna borrow my shovel...HA
Great Read Here.Around 14k miles 90% Non top tier gas.Just filled with Sunoco 240 and Tectron.Happy Motoring
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Patman (11-10-2018)
11-10-2018, 09:00 AM
#72
Melting Slicks
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Back to the original subject of this hijacked thread. Injector cleaners. It was my understanding, way back when direct injection gas engines were first being installed in C7 Corvettes, that because of the extreme high pressures that these injectors operate under, they didn't collect deposits. Does anyone know the truth? What is the collective wisdom in CF about this subject.
11-10-2018, 09:02 AM
#73
Race Director
Last edited by Patman; 11-10-2018 at 09:03 AM.
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Maxpowers (11-10-2018)
11-10-2018, 09:23 AM
#74
Race Director
Back to the original subject of this hijacked thread. Injector cleaners. It was my understanding, way back when direct injection gas engines were first being installed in C7 Corvettes, that because of the extreme high pressures that these injectors operate under, they didn't collect deposits. Does anyone know the truth? What is the collective wisdom in CF about this subject.
11-10-2018, 09:23 AM
#75
Back to the original subject of this hijacked thread. Injector cleaners. It was my understanding, way back when direct injection gas engines were first being installed in C7 Corvettes, that because of the extreme high pressures that these injectors operate under, they didn't collect deposits. Does anyone know the truth? What is the collective wisdom in CF about this subject.
11-10-2018, 09:53 AM
#76
Le Mans Master
11-10-2018, 10:03 AM
#77
E-Ray, 3LZ, ZER, LIFT
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Back to the original subject of this hijacked thread. Injector cleaners. It was my understanding, way back when direct injection gas engines were first being installed in C7 Corvettes, that because of the extreme high pressures that these injectors operate under, they didn't collect deposits. Does anyone know the truth? What is the collective wisdom in CF about this subject.
However although the pressures are very high the hole is very small! In addition it could provide some help with combustion chamber deposits. How much- don't know but if adding for the fuel sender- can't hurt he other!
11-10-2018, 01:32 PM
#78
Race Director
11-10-2018, 02:00 PM
#79
Melting Slicks
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Techron is great stuff and will likely remove any deposits in our injectors, just as it does on the older port injectors. My wish is to know if deposits can and do occur in our direct injectors. Inquiring minds want to know. 
11-10-2018, 02:30 PM
#80
What type of deposits (inside the injector) are you talking about?