SI with 87 octane gas *Threads merged*

[umibozu]

Originally Posted by volvo9

The fuels are just fine to mix. The downside is that as you know E85 contains roughly 1/3 less energy than gasoline so when running the fuel straight your fuel injectors need to deliver that much more to the engine to keep it from running lean. Most non flex fuel cars can handle around 30% ethanol in gas before the check engine light comes on for running lean, but every car is different, some can run much higher mixes just fine. When that happens just add some more gas and it'll go out. You may notice a drop in fuel economy, but some people also state a slight rise in fuel economy using e30, not sure why, but I've read it, and I find it easier to get higher Mpg out of my car with a gas/e85 mix than I can get with straight gas (for instance filling with gas when I have 1/4 tank of E85).

I run E85 in my Flex Fuel Taurus most of the time since a pump just opened up in Canton where I find myself driving by pretty often. Once I get my 97 Civic back up and running (I crashed it ) I'm going to mess around with it and E85, seeing how high of a mixture I can run on the stock fuel system and eventually modify it to be able to run 100% e85 or gas.

If you convert your civic, I do not recommend using an "E85 converter box" like Flex Fuel International. The FFI box comes with wire harnesses that go inbetween your injector and injector harness. The intent is to capture the signal and bump up the IDC. The problem is that box ONLY goes inbetween the injector and injector harness, it does not have the capability to monitor a wideband O2 sensor to measure A/F ratio for E85. FYI stoich for E85 is different than gasoline. To sum it up the E85 conversion kits blindly bump up IDC to compensate for the fact that you have to add more fuel. Not only will your injector life decrease but you could possibly have other major issues arise.

[OrdnanceMarine]

Originally Posted by umibozu

Our manuals also state to use "only genuine honda manual transmission fluid" however it has been proven amsoil synchromesh MTF outperforms in every aspect.

Would you mind showing me the "proof"? Amsoil's MTF seems to be a good fluid to use but I don't think it's any better than the reformulated MTF that Honda has been using for over 2 years.

[OrdnanceMarine]

Originally Posted by low&slow

stop beeing cheap people

Stop adding useless posts. If you'd read the conversation you'd realize that this goes way beyond the idea of saving a few bucks per tank.

[OrdnanceMarine]

Originally Posted by umibozu

The reason I started asking these questions was because I am considering a CT supercharger and would like to pump 91 octane and use E85 to raise the equivalent octane to 94-95 for an extra margin of safety.

I figured this is where you were coming from and I figured you knew what would be needed to compensate for the reduced energy content (and increased injector duty cycle) but thought I'd toss in the information so others didn't just start blending fuel without changing their tune or at least knowing what to keep an eye on.

[umibozu]

Originally Posted by OrdnanceMarine

Would you mind showing me the "proof"? Amsoil's MTF seems to be a good fluid to use but I don't think it's any better than the reformulated MTF that Honda has been using for over 2 years.

I was unaware of the reformulated Honda MTF. As far as "proof", I cannot supply nor have I found a scientific comparison of both MTF fluids side by side. The only thing I have found are the specs of the Synchromesh from Amsoil's website : AMSOIL - Synthetic Manual Synchromesh Transmission Fluid (MTF)

My comments were based on "user experiences" on multiple forums. But you are correct, I have no proof. Is the reformulated Honda MTF synthetic based ?

I'm curious enough to send my MTF to Blackstone for analysis now. But I would need to swap to fresh Honda MTF and drive for 3k miles. Then swap to Synchromesh for another 3k miles. I wonder if 3k miles would be enough to "stress" the fluid.

Sorry for the hijack, I'll stick on topic from here on out.

[umibozu]

Interesting article from a BMW rep :

Straight from the BMW spokesperson, we get the final verdict regarding using 89 or 87 octane gas in our 91 preferred cars.


Running On Regular: Do Premium Vehicles Really Need Premium Gasoline?

From Stan Baldwin online

Long before gasoline rocketed through $4 a gallon many people were dismayed to see a significant percentage of their income disappearing into the tank of their car. Today, a wobbly economic outlook, increases in the cost of most other forms of energy, as well as the cost of life’s staples, have prompted folks to look for every possible way to cut back on spending. “Can I save money by running my car on Regular?” “Will it hurt the engine?” my friends ask. More than one person driving a car the manufacturer has spec’d for Premium has told me “I use Regular and my car runs fine.” Are there consequences of “down grading” your fuel? It is definitely a timely question, so we sent e-mail inquiries off to a half dozen manufacturers asking about their technology and their policy on the matter.

While waiting for their reply let’s review some internal combustion engine characteristics. Fuel does not truly explode in a cylinder, at least it isn’t supposed to. It burns smoothly, albeit very rapidly, across the cylinder. The octane rating is a measure of the propensity a given fuel has to burning, rather than exploding. Gasoline “exploding” in the cylinder is frequently called “detonation” or more colloquially, “knocking” or “pinging”. These explosions, because they happen as the piston is rising during the compression stroke and try to shove the piston back down the bore, can do damage over time. In the case of severely stressed motors, such as in race cars, a few seconds of serious detonation can destroy the engine. Two of the mechanical considerations affecting how smoothly a fuel burns are compression and cylinder head configuration. Two variable considerations of great importance are the temperature in the cylinder and the ignition timing. Every manufacturer designs and builds their engines to operate most efficiently for the application intended with a gasoline of a particular octane rating.

Not all that long ago, before the advent of engine management systems, the result of tanking up a high compression vehicle with standard grade fuel was immediately obvious. Providing the stereo wasn’t cranked up past 100 decibels, the pinging or knocking from the engine compartment let you know something was not right. Driving up a hill, towing a load or simply accelerating quickly produced an unnerving rattle from under the hood. It sounded very much like your carbureted V-8 had morphed into a diesel. Until the age of microprocessors enabled the creation of engine management systems, the consequence of a steady diet of low octane fuel could be fatal for a high performance engine.

General Motors, Honda, Toyota and BMW responded to our inquiry. Honda’s public relations representative declined to comment on the issue. Toyota noted that essentially all their current models are designed to run on 87 octane. I asked about using 85 octane, available in some markets, and Bill Kwong of Toyota corporate PR told me they would run fine, with maybe only a slight 2-3 percent decline in horsepower and fuel mileage. But 85 octane is usually only offered in markets at altitude (i.e. Denver, Colorado) where the reduced oxygen doesn’t allow an engine to reach full designed power in any event. If you drive a modern Toyota, the octane rating of your fuel isn’t much of an issue. But what about a brand aimed squarely at the performance market? What about BMW?

Thomas Plucinsky, BMW Product and Technology Communications Manager told us all BMW engines are designed to run on 91 octane. All performance testing, including EPA emissions and fuel mileage, is done with 91 octane. However, though BMW is all about performance, their motors will run on 89 or 87 octane without damage. The knock sensors pull the ignition timing back and eliminate detonation. There will be a loss of power and a decrease in fuel mileage, but the size of the horsepower loss and the increase in fuel consumption depends upon many factors, such as ambient temperature, exact formulation of the fuel and driving technique, so BMW does not offer any estimates for operation on lower grade fuels. One not so obvious concern, Mr. Plucinsky noted, is the type and quality of additives the gasoline companies include in the fuel. Premium gasolines may have better additive packages which are more effective keeping fuel systems (particularly injectors) clean and working efficiently, than those in regular grade fuels or off-brand products. Using lower octane or off-brand fuel could be degrading the fuel system over time, setting you up for a repair bill down the line.

Dave Muscaro, Director of Engine Development/Calibration for GM power trains explained GM has “three flavors” of fuel specification for their offerings: Regular (87 octane) Recommended, Premium (91) Recommended, and Premium Required. Again, we are more concerned with the last two categories where regular could be substituted for the specified Premium. All the engines have a knock sensing ability that retards the spark when detonation occurs. For the premium recommended vehicles the spark advance will be pulled back enough to eliminate the detected knocking. The typical driver will not notice a performance decrease, except under load, and mileage will decline slightly. The engines intended for performance, such as the LS7 or the supercharged small block V-8, are Premium Required powertrains. The customers clearly were not primarily concerned with economy when they chose a performance vehicle and GM optimizes the engine management system to deliver the highest possible power output at all times. To this end the detonation control system does not retard the spark to the point required to prevent all knocking. It would seem a determined deranged drag racer could run Regular in his Corvette and, over time, he might manage to melt a piston or two.

If burning 87 octane in your car, when 91 octane is specified, will not harm the engine, and the performance degradation is not noticeable in typical driving, how much money can you save? The Energy Information Administration, U.S. Government Department of Energy, offers some figures for US gasoline retail prices (these are averages, all areas, all formulations). A year ago Regular was going for $2.982 a gallon and Premium was commanding $3.196 a gallon. The 21.4 cent difference delivered a 6.7 percent saving over Premium. This June 23, 2008, Regular extracted $4.079 from your wallet while Premium sucked up $4.312 for every gallon. The differential (23.3 cents) has grown slightly since 2007 but buying Regular is now only 5.4 percent cheaper than Premium. Since 5 percent is roughly the typical percentage of mileage decrease to be expected with the 87 octane fuel in a 91 octane engine, is there any savings at all?

Bottom Line: Most modern engines are fuel injected and controlled by sophisticated engine management systems which can rapidly and accurately compensate for lower octane fuel by retarding the ignition. Running these cars on 87 octane will not hurt them. However, the immediate savings at the pump may be wiped out by the subsequent drop in fuel mileage and performance, not to mention the possibility of damage over time.

[OrdnanceMarine]

From what Hondata has put together in their help file for FlashPro the Si does not pull ignition to combat knock. From my own limited personal experience I've seen the ECU dump in extra fuel when a knock was registered but not pull ignition.

[OrdnanceMarine]

Originally Posted by umibozu

I was unaware of the reformulated Honda MTF. As far as "proof", I cannot supply nor have I found a scientific comparison of both MTF fluids side by side. The only thing I have found are the specs of the Synchromesh from Amsoil's website : AMSOIL - Synthetic Manual Synchromesh Transmission Fluid (MTF)

My comments were based on "user experiences" on multiple forums. But you are correct, I have no proof. Is the reformulated Honda MTF synthetic based ?

I'm curious enough to send my MTF to Blackstone for analysis now. But I would need to swap to fresh Honda MTF and drive for 3k miles. Then swap to Synchromesh for another 3k miles. I wonder if 3k miles would be enough to "stress" the fluid.

Sorry for the hijack, I'll stick on topic from here on out.

The reformulated MTF is supposed to be at least partially syn though my information might be out of date since I haven't worried about it for a year or so. Both seem to be good fluids and you're not likely to spot much on a used oil analysis for either after only a few thousand miles especially since the key characteristicts of MTF are not likely to show up on a UOA since there's no combustion in the transmission to dirty things up. You will find that one is basically a 5w30 and the other a 10w30. Personally I'd stick what's working but I thought you might have seen something that really tipped the scale towards AMSOIL's MTF.

[tehnighthawk]

I have used 89 octane in the last few tanks and have noticed some pinging at high load, low rpm situations. I will be going back to 93.

[Steel_RAin]

Buddy has run 87 on his 2007 Si for 60k, zero problems.

[BV1]

Originally Posted by Steel_RAin

Buddy has run 87 on his 2007 Si for 60k, zero problems.

I created a FlashPro specific base map (SD/AFM) for 87 Octane, tuned for lower quality gasoline without sacrificing too greatly in other areas.

I finished testing and demoing on it last week, and it is tuned for 0 knock count on a stock internal Si... I/H/E and related mods are ok.

The worst knock with the 87 Octane gas was 1400-2200 near WOT, it has since been repaired, and all areas of the map adjusted for a minor reduction in cylinder dynamic pressures.

I will host it when I get a chance.

Steve

[OrdnanceMarine]

Originally Posted by BV1

I created a FlashPro specific base map (SD/AFM) for 87 Octane, tuned for lower quality gasoline without sacrificing too greatly in other areas.

I finished testing and demoing on it last week, and it is tuned for 0 knock count on a stock internal Si... I/H/E and related mods are ok.

The worst knock with the 87 Octane gas was 1400-2200 near WOT, it has since been repaired, and all areas of the map adjusted for a minor reduction in cylinder dynamic pressures.

I will host it when I get a chance.

Steve

Did you find yourself making mostly ignition changes? Wonder what the difference on the dyno back to back between tuned for 91 and tuned for 87 would look like.

It does seem pretty silly, though. $700 for FlashPro plus whatever other mods that really improve the output of the K20Z3 motor and then tune it for 87 and save a whopping $2.00-$2.40 PER TANK!!!

I've averaged 35 MPG over the 2X,000 miles I've had my Si, so if I maintained that fuel economy I could save $571 over 100,000 miles assuming that you can achieve identical MPG between 87 and 91. Again, seems pretty darn silly when that fuel over 100,000 miles at $3.20/gal would have cost $10,000 and the car with mods runs ~$25,000.

[BV1]

Whatever the reasoning may be, people still run 87, some have no choice due to location, other due to savings.

There is more BTU's of energy in Heptane then in Octane, even with the reduction in timing and cam angles, mileage still went up a small amount on the 87 Octane, 430-50km/tank mixed to 450-70 km/tank.

It is now the "backup" map on the FlashPro, better to have an option, then none.

Steve

[ryker]

Originally Posted by OrdnanceMarine

It does seem pretty silly, though. $700 for FlashPro plus whatever other mods that really improve the output of the K20Z3 motor and then tune it for 87 and save a whopping $2.00-$2.40 PER TANK!!!

I've averaged 35 MPG over the 2X,000 miles I've had my Si, so if I maintained that fuel economy I could save $571 over 100,000 miles assuming that you can achieve identical MPG between 87 and 91. Again, seems pretty darn silly when that fuel over 100,000 miles at $3.20/gal would have cost $10,000 and the car with mods runs ~$25,000.

What seams silly is buying a Si then driving it so lightly that it gets the same MPG as a r18.

[ryker]

Originally Posted by umibozu

I

Thomas Plucinsky, BMW Product and Technology Communications Manager told us all BMW engines are designed to run on 91 octane. All performance testing, including EPA emissions and fuel mileage, is done with 91 octane. However, though BMW is all about performance, their motors will run on 89 or 87 octane without damage. The knock sensors pull the ignition timing back and eliminate detonation. There will be a loss of power and a decrease in fuel mileage, but the size of the horsepower loss and the increase in fuel consumption depends upon many factors, such as ambient temperature, exact formulation of the fuel and driving technique, so BMW does not offer any estimates for operation on lower grade fuels.

If burning 87 octane in your car, when 91 octane is specified, will not harm the engine, and the performance degradation is not noticeable in typical driving, ....


. However, the immediate savings at the pump may be wiped out by the subsequent drop in fuel mileage and performance, not to mention the possibility of damage over time.

Good article.

I'd love to see dyno charts on a Si for with and without correct octane.

[OrdnanceMarine]

Originally Posted by BV1

Whatever the reasoning may be, people still run 87, some have no choice due to location, other due to savings.

There is more BTU's of energy in Heptane then in Octane, even with the reduction in timing and cam angles, mileage still went up a small amount on the 87 Octane, 430-50km/tank mixed to 450-70 km/tank.

It is now the "backup" map on the FlashPro, better to have an option, then none.

Steve

I totally understand your reasoning as stated and also agree that heptane does contain slightly more energy than octane, which is the reason why MPG usually goes down very slightly when you burn 91 in a car designed for something less. You may be revealing that there is quite a bit of margin in the Si when run on 91, enough that with careful and proper tuning you can feed it 87 and see little loss in performance and a few percent improvement in FE. Our compression ratio really isn't that high compared with some of Honda's K24's that are running 87.

[OrdnanceMarine]

Originally Posted by ryker

What seams silly is buying a Si then driving it so lightly that it gets the same MPG as a r18.

Actually, if I had a R18 Civic I'd put money on the idea that I'd be closer to 42-45 MPG. It's also interesting that most of the other car sites I post on have numerous members that consider a 20-50 trips through the first three gears going to 8000+ RPM and a few drag-style launches per tank of fuel to be "abuse". Only here at 8th would that be regarded as so lightly . I think that's what makes this an entertaining place to visit.

[BV1]

Originally Posted by OrdnanceMarine

From what Hondata has put together in their help file for FlashPro the Si does not pull ignition to combat knock. From my own limited personal experience I've seen the ECU dump in extra fuel when a knock was registered but not pull ignition.

Just to share on this (missed your post earlier)....

The ECU does pull ignition... it pulls it in steps, via the knock sensor.

It also holds the ignition value steady, even if the map calls for more, after a knock count, it will not increase the ignition... so if it deems a knock count at say 15 degrees, it will pull down the timing slightly (0.5 degrees at first) and then gradually more.... to 14, 13... and then if knock stops... it will hold at 13for a time, even if the map calls for say 20 degrees as the RPMS increase etc... resulting in over 7 degrees knock retard, even though only 2 degrees were pulled initially.

It can be confusing to see this happen in logs, but this is how FP works currently.

Just sharing to increase your knowledge base. Do you have FP? If so you can add the variable "Knock Retard" to the Graph function and witness this affect in your datalogs.

As I mentioned, a good way to tune these knock tables is to increase sensitivity until 2-3 degrees are being pulled across the board at all times... then make your desired changes (fueling, cams etc) and after, reduce the sensitivity until IGN timing is just not being pulled, as in it is just on the threshold of pulling timing.

[OrdnanceMarine]

Originally Posted by BV1

Just to share on this (missed your post earlier)....

The ECU does pull ignition... it pulls it in steps, via the knock sensor.

It also holds the ignition value steady, even if the map calls for more, after a knock count, it will not increase the ignition... so if it deems a knock count at say 15 degrees, it will pull down the timing slightly (0.5 degrees at first) and then gradually more.... to 14, 13... and then if knock stops... it will hold at 13for a time, even if the map calls for say 20 degrees as the RPMS increase etc... resulting in over 7 degrees knock retard, even though only 2 degrees were pulled initially.

It can be confusing to see this happen in logs, but this is how FP works currently.

Just sharing to increase your knowledge base. Do you have FP? If so you can add the variable "Knock Retard" to the Graph function and witness this affect in your datalogs.

As I mentioned, a good way to tune these knock tables is to increase sensitivity until 2-3 degrees are being pulled across the board at all times... then make your desired changes (fueling, cams etc) and after, reduce the sensitivity until IGN timing is just not being pulled, as in it is just on the threshold of pulling timing.

Thanks for the insight. The only knock counts I've seen has been the result of some sort of harmonic or other artifact (usually one count passing through a certain RPM at a certain MAP/throttle setting). I'm not sure I was looking at my logs closely enough to notice one degree changes, nor would I probably see them with one knock events. What I do remember seeing was the injector pulse width go way up and then the lambda value drop significantly just after one knock count was logged.

I'm starting to get the itch to go back out and mess with FlashPro some more after pretty much laying off of it for the past few months. I've been really tied up trying to finish my masters degree, working on home improvement projects and getting ready for our third baby so I probably won't have time much time for the next few months to really dive in and go to the next level of FlashPro knowledge (not much more than a beginner at this point which is why I paid to have it dyno tuned with plans to fine tune it from there).

[titan]

Hello all,



I didn't want to make a new thread so I'd figure I just ask in this one since there's been so many views/replies:

For those that purchased a used Civic SI, it's virtually impossible to know the exact history of the previous owners. They can say they've been using 91(93) or 89, but unless they have stacks and stacks of receipts, it's hard to prove. Heck, they can be running 87 all this time, but figured they better tell you what you want to hear. What's done is done....

So for those that end up buying a used SI, what are the steps/procedures to take to ensure that your engine lasts as long as it would've if you had bought it new? Short of rebuilding it, what are the used owners doing? Fuel cleaners? Boosters?

Just need some good input from all parties for those that may want to pick up a used SI in the future....


Thanks all!