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I just bought a 87 Samurai yesterday. I will have lots of questions in the near future. The first one is, What octane gas does the Samurai run best with and is it OK to go with the ethanol added gas since the ethanol free is hard to come by? Thanks!
 

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If it's stock it will run fine on regular pump gas.
I always go for the highest octane rating. Mine is far from stock though.
Ethanol is an un avoidable evil in this country. Just don't let it sit to long and maintain you're filters......
 

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I have a 92 fuel injected model and I use regular gas, but every couple fill ups I will fill up with the higher grade to clean things out. Also when I use regular, I rotate using fuel cleaner then injector cleaner to make sure it is running clean.

Enjoy your Sami and welcome to the family :D
 

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Non-ethanol fuel will afford you slightly better responsiveness and MPG, pure gasoline has more energy per gallon. I tried ethanol while commuting and it was a cheaper fill up but my MPG suffered enough that it was a wash so I opt for pure gasoline. I have not run it on a dyno but seat of the pants tells me the pure gasoline nets better power. I live up some serious hills and I can see a difference in top speed when I reach the top, in my Marquis, Samurai and the Saab. It's not day and night but it is a difference. Ethanol is tough on old school stuff, it works fine in flex fuel vehicles but for the rest of us its a stretch. NEVER EVER EVER go more than 10% IF you have to use it.

Ethanol sucks in carb vehicles, NEVER EVER EVER use it in your small engines like your saw, splitter, line trimmer etc. I keep it out of mine and I'm going on several seasons on my Stihl without ever having to touch it, and this saw never goes out of season. Before I found the pure gasoline again the small engines were a constant fight with the carb issues, especially if they sit for a month or so.

I wont even begin to discuss how my not quite stock turbo Saab 9-5 feels about ethanol tainted fuel under boost conditions.

I could rant for pages but seriously with pure gasoline my Saab picks up 3mpg across the baord, there is like 1-2 stations left in the area that are not tainted. I'm not sure of the MPG gains with the Samurai but it is noticable climbing hills and I fill up less.

/-rant mode off
 

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Stock engine = stock octane requirements, which in this case is 87.

Fuel grade does not automatically relate to detergent content or even quality.

E10 makes marginally more power over straight gasoline when the mixture is adjusted to compensate, otherwise it may make the same or marginally less.

10% ethanol should cause about a 4% drop in economy as a rule of thumb; E85 about a 33% drop. I don't know of anywhere that E85 is 33% cheaper than gas, so it's actually more expensive to use. The environmental "benefits" of ethanol as a clean fuel have proven to be a complete fabrication as well.
 

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I will agree. 4% is probably on the low side of my loss of MPG on level ground.

With my Marquis I lost about 8-10% through my 3 hour each way commute (2x week only) I was monitoring my fuel with odo, Scangauge 2 and fuel receipts with same fill-up points. When I took the scenic route it was noticeably less enthusiastic up the hills or to reach 110mph. It was a stock 4.6L EFI in a 4200lb car with no adjustments to compensate for tainted fuel. I nearly kissed 28 with real gasoline and with 10% tainted it would vary from 24-25 @ 60, less consistent MPG as well. The performance hit was not to obvious until I jumped on it, passing gaggles of Harleys and RVs, taking hills etc.

With the Saab I went from 31-ish combined to 27-ish combined. I have gone back and forth a couple times and the results are pretty consistent. Under boost it bucks and protests a bit where as with pure gasoline its a clean solid boost, same oct. No modifications made to burn tainted fuel. (BCB stage 2 ecu, 3"DP/race cat, CAI, 5sp)

With the Samurai I have not measured but I would say the economy is probably closer to 4% than the 10-ish I have realized on my other vehicles. The power hit is noticeable on hills and highway. I'm not real sure what I can do to take advantage of more potential power but I'm sure not seeing it with any of my vehicles. If there is something I can to do tell it the fuel is ethanol tainted I would love to know how. Every time I switched between fuel types I unplugged the battery so the ECU could relearn the new fuel and ran it for a while before switching back. Last time I checked there was no ethanol friendly tune for it.

As far as the environmental impact, it is HUGE. Tens of thousands of acres of beautiful untouched grasslands and preservation lands were plowed over to plant more corn, local water sources polluted, corn prices shot way up. This information is all out there for the viewing. The damage from this is far greater than we were lead to believe when this idea was being pitched (sharp understatement of the cons, see a pattern here?). I'm no tree-hugger but this is so far from a good thing I cant find words suitable for use in public.
 

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With the Saab I went from 31-ish combined to 27-ish combined. I have gone back and forth a couple times and the results are pretty consistent. Under boost it bucks and protests a bit where as with pure gasoline its a clean solid boost, same oct. No modifications made to burn tainted fuel. (BCB stage 2 ecu, 3"DP/race cat, CAI, 5sp)
It would be interesting to see what a wideband reports when it's misfiring.

I think boosted cars may be more sensitive, especially older ones with first-generation digital EFI. I had an '84 Mustang SVO that would pull timing like crazy pretty much everywhere but on the top end because it was detecting knock. I always wanted to give it some 100 just to see how it liked good fuel, but sold the car before that ever happened. It's hard to put $100+ in a 15gal tank. :eek:

FYI, unleaded gas has to be oxygenated with 10% ethanol in order to be sold for use on-highway in CA....by law. That includes "race" fuels like VP StreetBlaze 100.
 

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The oxygenation requirement blows. I have only the deepest respect for the 2.3 Turbo fords. Had a 74 Pinto with a lightly modified 2.3 Turbo from a Super Coupe. Sleeper... yea! It was back when all gas was pretty good and would easily rival most V8s after 30 mph. The worst issue I had was keeping the carbs synchronized.

I have never programmed fuel injection so I'm not sure whats going on with the Saab, I assume the knock sensor is detecting something not right and dropping the timing. The Pinto I had was just super angry all the time and never missed a beat aside from 2 transmissions and a rear end.

This Saab is a 2005 9-5 so its the last of the REAL Saab engines (not a turbo charged Chevy engine like the 9-3 or later 9-5). I assume modern EFI can compensate for bad fuel with 02, knock sensors et al. I grew up with carbs and all adjustments were seat of the pants and a film canister full of different jets. Manually recurving distributors etc. This is all gone now.

So to not veer tragically off topic, I have no idea how to compensate for this different fuel. If there is more power potential there I wonder if folks who write tunes can write a Ethanol friendly tune.

More specifically, what can be done to the Suzy to help with this. I'm not terribly concerned with MPG, its pretty darn good for rolling on 35s but if I could squeeze even 5 more HP I would be tickled, or even broaden the torque curve a little, anything at all. If I'm not mistaken you cannot re-flash the Suzy ECU, is this correct? If you can would writing a current tune with this tainted fuel in mind help in the slightest way?

How to compensate?
 

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The oxygenation requirement blows. I have only the deepest respect for the 2.3 Turbo fords. Had a 74 Pinto with a lightly modified 2.3 Turbo from a Super Coupe. Sleeper... yea! It was back when all gas was pretty good and would easily rival most V8s after 30 mph. The worst issue I had was keeping the carbs synchronized.
I wanted to do that same swap with a pinto just to get away from smog checks. '75 and earlier vehicles are exempt in CA. There's no rolling 25- or 30-year exemption anymore though. :rolleyes:

I have never programmed fuel injection so I'm not sure whats going on with the Saab, I assume the knock sensor is detecting something not right and dropping the timing. The Pinto I had was just super angry all the time and never missed a beat aside from 2 transmissions and a rear end.
I'd suspect knock if it noses over, but actually misfiring could mean something else like spark blowout or too little/too much fuel.

I assume modern EFI can compensate for bad fuel with 02, knock sensors et al.
It depends on the generation and hardware capabilities. A lot of modern cars, especially European and Japanese makes starting being equipped with wideband O2 sensors in the '90s. The VW 1.8T is one of them and a simple chip tune can increase the power by 50% on stock parts. :eek:

So to not veer tragically off topic, I have no idea how to compensate for this different fuel. If there is more power potential there I wonder if folks who write tunes can write a Ethanol friendly tune.
If the fuel and spark maps can be altered, then yes, the ECU can be adjusted to make the engine happy on E10. It's done all the time for people running E85 in non-flex fuel vehicles.

More specifically, what can be done to the Suzy to help with this.
A carbureted engine just requires larger jets and perhaps some tweaking to the ignition advance, but it's anyone's guess if soft parts in the fuel system will tolerate alcohol.

I'm not terribly concerned with MPG, its pretty darn good for rolling on 35s but if I could squeeze even 5 more HP I would be tickled, or even broaden the torque curve a little, anything at all. If I'm not mistaken you cannot re-flash the Suzy ECU, is this correct? If you can would writing a current tune with this tainted fuel in mind help in the slightest way?

How to compensate?
EFI Suzukis apparently can be chipped with either a simple socket mod and EPROM or a daughter board with programmable memory. Rhinoman has a site with more info about that.
 

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I'm still messing with my custom dashboard, its taking me forever even though I'm just hanging gauges and switches in it now. The pain is keeping the days short. I plan to have the cam reground to widen the torque curve. a daughterboard might be a good answer to. I have a few ECUs I can play with to, going to go through them and inspect/replace caps/test and a reflash might be good, just to many places where you simply cannot buy pure gasoline.

Oh yea, the 1.8T (or TDI) is one of my fav engines, I was looking for one but one did not turn up in the right price range. Chipping my 08 GTI (miss her very much) made a considerable difference to an already decently quick car.

I think for the Tracker powered Sami I will see about getting an ECU worked over and maybe a cam grind and be happy with that. As long as I can do 70 into a headwind and hold hills a little better I'll be happy, gotta love it for what it is.

Tony
 

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The thing about chipping a stock ECU that uses non-flash ROM is that you either have to pull+erase+reprogram it for every change or use an expensive EPROM emulator to make on-the-fly changes to the binary, then save the final version and burn it to a chip. In cases where the budget has room for a standalone ECU, that's what I recommend: a standalone ECU. Most of them can use a flex fuel sensor to adjust for any ethanol content too.
 

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It sounds like a decent amount of effort for minimal gain. It would be great to see someone write a tune for one rather than customizing. I'm lagging behind in the ability to alter a tune in an ECU, this is something I will have to learn.

It really sounds like the only cost effective way to deal with this is to keep it as is and just burn the pure gasoline when I can find it. For the Saab I will probably head to Sturgis for fill ups where I can buy pure gasoline.
 

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It sounds like a decent amount of effort for minimal gain. It would be great to see someone write a tune for one rather than customizing. I'm lagging behind in the ability to alter a tune in an ECU, this is something I will have to learn.

It really sounds like the only cost effective way to deal with this is to keep it as is and just burn the pure gasoline when I can find it. For the Saab I will probably head to Sturgis for fill ups where I can buy pure gasoline.
The level of difficulty is commensurate with the level of quality IMO.

A cheap way to sort of compensate on the mixture end would be to raise the fuel pressure slightly.
 

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I would agree, time spent designing a good tune would be great, I bought my Saab tune from those that live and breathe Saabs and I am freaking delighted with it. There are lots of fly by night vendors that sell tunes/ecus for various vehicles.

I have a Bosch ext fuel pump rated at... 85 psi I think, the factory fuel regulator is in place on the rail and everything else is stock. Is there a way to jack it up a few lbs w/o replacing the reg?
 

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Probably not. There again, I always recommend leaving fuel pressure alone/stock and tuning the pule width directly whenever possible.

Are we talking about the Saab or the Suzuki?
 

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I was talking about the Suzy, I was using the Saab as an example of the great work someone can do with tons of research and wisdom, lots and lots empirical data and just plain ol' love for the job.

I have come to accept that the Suzy is what it is, short of a turbo or a lot of extra $ in I will have to be content with its performance. I am always listening up for ways to make it just a little better without doing major work. Even making it work better with tainted fuel would be a plus. I'll have to look into the possibility of having it flashed or remapped.
 
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