Octane booster recommendation
08-01-2016, 12:35 AM
#31
Race Car
Thread Starter
Didn't time it but seemed around 15 min for about 14 gallons. You've told me about the Durametric before but I had forgotten. The relay jumper was easy enough to use that I will probably just use it again next time. I put some solder on each end of a piece of #10 then pounded it flat and trimmed in about half.
08-01-2016, 01:31 AM
#32
Drifting
The royal Purple (listed above) claims to boost it 30 points so theoretically it would have brought it up to 90. I normally run 91 without issue. The car kept dying even though I was trying to baby it and didn't want to restart. I let it sit there and idle for a little bit after add in the bottle and still having problems and then it settled down and ran fine. So I figure m it really worked as advertised or the ECU adjusted to the bad gas coincidentally at about the same time.
FYI, it was explained to me is that if you have a tune, an episode like this can really screw some stuff up since it doesn't allow the ECU to adjust.
FYI, it was explained to me is that if you have a tune, an episode like this can really screw some stuff up since it doesn't allow the ECU to adjust.
08-01-2016, 01:43 AM
#33
Race Car
Thread Starter
Ha! I had no idea I was walking face first into a full blown controversy. The whole thing seemed like a simple story. Lol. I am going to see if anyone around here will test gasoline samples. Maybe it will shed some light on the situation.
08-01-2016, 01:49 AM
#34
Didn't time it but seemed around 15 min for about 14 gallons. You've told me about the Durametric before but I had forgotten. The relay jumper was easy enough to use that I will probably just use it again next time. I put some solder on each end of a piece of #10 then pounded it flat and trimmed in about half.
08-01-2016, 11:33 AM
#35
Race Director
Slakker, the reason you are unable to siphon gas from the tank, (like grandpa used to do from his beloved old Grand Torino) is all modern cars have a ball-check or shutter valve at the top of the tank. This is to prevent gas from spilling out in a roll over or other crash that damages the filler cap area. Jamming a smaller hose or other crap into the valve may damage the expensive, delicate mechanism, making it impossible to fill the tank at a gas station.
Gasoline in a complex compounding of 500 straight chain and branched chain hydrocarbons. Regular and premium grades are 99% alike, premium only differing in the blending of slightly more small branched hydrocarbons and/or additives that only exert themselves under the extreme conditions that cause ‘engine knock’.
No petroleum engineer or engine designer would account your experience of poor idling, stalling, hard starting to the gasoline octane number.
The online owner’s manual for 1999, like the manual for more modern P cars, does state the requirement of higher octane gasoline, but recognize a situation when only lower octane gas may be available. It says to go ahead and temporarily use it as the engine’s knock sensor system will prevent any harm.
Gasoline in a complex compounding of 500 straight chain and branched chain hydrocarbons. Regular and premium grades are 99% alike, premium only differing in the blending of slightly more small branched hydrocarbons and/or additives that only exert themselves under the extreme conditions that cause ‘engine knock’.
No petroleum engineer or engine designer would account your experience of poor idling, stalling, hard starting to the gasoline octane number.
The online owner’s manual for 1999, like the manual for more modern P cars, does state the requirement of higher octane gasoline, but recognize a situation when only lower octane gas may be available. It says to go ahead and temporarily use it as the engine’s knock sensor system will prevent any harm.
IIRC Porsche states the lowest octane that should be used 90. The OP put in 87.
These engines have a very high compressoin ratio and 87 octane is not up to it.
Based on the fact 90 is the lowest octane grade Porsche says is ok to use I suspect the DME is unable to adjust the timing enough to accomodate 87 octane.
Or possibly in attempting to adjust the timing the timing is delayed so long the engine simply won't run right? Also, by delaying timing this raises the exhaust gas temperature and thus exhaust valves, O2 sensors, converters are at risk of damage from this elevated exhaust gas temperature.
I think the way the engine was running was due to the 87 octane and I think it is a mistake -- to put mildly -- to assume the OP can just drive the gasoline out.
Maybe he can, but if he can't there's a lot at risk.
I prefer to sacrifice the least costly item in this situation and that's the 87 octane gasoline in the tank. Hence my recommendation to drain the tank.
If the gasoline can be saved to be used in another compatible vehicle, that's fine, if one is comfortable with that much gasoline around hopefully in appropriate containers.
08-01-2016, 11:52 AM
#36
Former Vendor
Like I said, pop off the fuel line and place an extension hose into a container that's safe to store fuel in... and bypass the fuel pump relay... The tank will be emptied in about 5 minutes, as well as the fuel system.
Refill with the proper fuel, and give the DME some miles to adapt. You'll be good.
We drain the fuel this way in ever6y car that we see for an engine reconstruction. I don't trust the fuel that was in the tank, under any circumstance.A new engine has zero tolerance for that.
Refill with the proper fuel, and give the DME some miles to adapt. You'll be good.
We drain the fuel this way in ever6y car that we see for an engine reconstruction. I don't trust the fuel that was in the tank, under any circumstance.A new engine has zero tolerance for that.
08-01-2016, 12:01 PM
#37
Race Car
Thread Starter
Like I said, pop off the fuel line and place an extension hose into a container that's safe to store fuel in... and bypass the fuel pump relay... The tank will be emptied in about 5 minutes, as well as the fuel system. Refill with the proper fuel, and give the DME some miles to adapt. You'll be good. We drain the fuel this way in ever6y car that we see for an engine reconstruction. I don't trust the fuel that was in the tank, under any circumstance.A new engine has zero tolerance for that.
See above. Completed last night and running great today.
08-01-2016, 02:01 PM
#39
Race Car
Thread Starter
08-01-2016, 03:17 PM
#40
Racer
Join Date: Aug 2015
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I should probably put my Flame Suit on before writing this, but on my Fuel cap it says MINIMUM RON 91
This is what I got from Petro Canada website :
A vehicle that calls for "91 RON" should use 87 octane gasoline
Now, go ahead, flame away
This is what I got from Petro Canada website :
A vehicle that calls for "91 RON" should use 87 octane gasoline
Now, go ahead, flame away
08-01-2016, 03:20 PM
#41
Macster, if you peruse the American Petroleum Institute’s web site you will find, after distilling down all the technical explanations, that the only difference between regular and premium grades of gasoline is the antiknock capabilities. Hence the reason several people commented that the difference in octane rating would not cause the hard starting etc symptoms, and would not be fixed by the addition of some rather useless booster additive.
Humans are funny, they like to jump to conclusions. On the other hand, we are led to understand that cars only obey the laws of logit. However, what would you think, if your somewhat aging car started acting up. You being a big strong hothead man’s-man cursed and said “you ungrateful SOB, if you don’t stop this right away, I’m getting the 20# sledge hammer from the other side of the garage and beat the hell out of you”. Now if at that exact moment the car started running perfectly what would you conclude? Your big manliness scared the car, or your actions had nothing to do with it and the hiccup corrected on its own. The OP’s lack of attention to detail caused him to put the wrong fuel in the car, so it gives pause to wonder about his powers of observation (just joking).
By the way, this simple DME has no idea what grade of fuel is being used. It can only react to engine knock. If I’m find myself in some scary Hill Billy town late at night and only the regular gas pump outside the sketchy bar is working. I’m going to pump enough of that stuff to get to civilization. Crossing the great flat high planes of the U S, even a high performance Porsche engine will never know if I slip it some low octane gas. The caveat is that I must keep the engine in a happy RPM range and use a super light throttle. Of course nobody wants to live like that and the danger of engine detonation (knock, ping) is not worth the risk on a regular basis.
Humans are funny, they like to jump to conclusions. On the other hand, we are led to understand that cars only obey the laws of logit. However, what would you think, if your somewhat aging car started acting up. You being a big strong hothead man’s-man cursed and said “you ungrateful SOB, if you don’t stop this right away, I’m getting the 20# sledge hammer from the other side of the garage and beat the hell out of you”. Now if at that exact moment the car started running perfectly what would you conclude? Your big manliness scared the car, or your actions had nothing to do with it and the hiccup corrected on its own. The OP’s lack of attention to detail caused him to put the wrong fuel in the car, so it gives pause to wonder about his powers of observation (just joking).
By the way, this simple DME has no idea what grade of fuel is being used. It can only react to engine knock. If I’m find myself in some scary Hill Billy town late at night and only the regular gas pump outside the sketchy bar is working. I’m going to pump enough of that stuff to get to civilization. Crossing the great flat high planes of the U S, even a high performance Porsche engine will never know if I slip it some low octane gas. The caveat is that I must keep the engine in a happy RPM range and use a super light throttle. Of course nobody wants to live like that and the danger of engine detonation (knock, ping) is not worth the risk on a regular basis.
08-01-2016, 03:53 PM
#42
Race Car
Thread Starter
So are you volunteering to drain yours almost empty and then try 10 gallons of 87 to see if your experience is different? It would be great to get some additional data one way or another.
08-01-2016, 04:34 PM
#43
Rennlist Member
No one has used 87 before or if so, either experienced no issues or not willing to report.
My unscientific conclusion about your issue is that you got to the bottom of the tank of a 15 year old car and your fill-up stirred up whatever was lurking at the bottom of the tank and made its way into the fuel system. You mentioned that you were low on fuel before filling, was your low fuel light on?
Sounds like you're on your way to a fix - congrats and also we'll all be waiting for a report next year on the 3.8 conversion.
08-01-2016, 06:40 PM
#44
Race Car
Thread Starter
08-01-2016, 07:13 PM
#45
Well Slakker and Jhbrennan, you don’t need amateur antidotal observations per se, as there is 100 plus years of scientific research on every facet of this matter. Just as a side thought, have you ever driven the 30 mile Mt Evens Scenic Byway? The 14,000 foot altitude will mean that a Porsche will run as best it can (at that altitude) without a hint of engine knock on #87 octane. The thin air means that notwithstanding the high compression ratio the Mean Effective Pressure in the cylinder will never reach a level that will promote pinging, knocking.
Jhbrennan, one thing I often hear people say is not to run the fuel level extremely low in the tank. They explain as you did that the engine will now pick up the gunk from the bottom of the tank with deleterious results. I’ve never been able to get my head around this. I assume the fuel pick up is always at the bottom of the tank and every bump, corner and movement of the car should be constantly mixing the gas, so what difference does it make if you run the tank only half empty or almost all empty before refueling?
Slakker was this gas 10% ethanol? If so as there is a greater chance of getting phase separated or water contaminated fuel.
Jhbrennan, one thing I often hear people say is not to run the fuel level extremely low in the tank. They explain as you did that the engine will now pick up the gunk from the bottom of the tank with deleterious results. I’ve never been able to get my head around this. I assume the fuel pick up is always at the bottom of the tank and every bump, corner and movement of the car should be constantly mixing the gas, so what difference does it make if you run the tank only half empty or almost all empty before refueling?
Slakker was this gas 10% ethanol? If so as there is a greater chance of getting phase separated or water contaminated fuel.