DrElvee

So I tried 95 octane for the first time and the car responded well.
However I've heard and red here that ISF and some RCF guys do a 3-4 gallon e85 to a full tank 91 and have been getting really good results.
I've searched and red every thread going back to 2009 but all I see is e85 with 91.
If the point of blending is to lift octane, then wouldn't 100 octane be as good as it gets? And safer?
So my question is, what are the benefits of running e30 (e85+91) vs 100 octane? Or 95 for that matter. Our engines are 12.3:1 compression and I can definitely see the benefit of 100 octane, but e30 has less total energy than 100oct.
Anyone dyno the difference between e30 vs 91 or 95 or even 100?
I'm just confused with the blending part.. 4 gallons of e85 with 12(ish) 91 would equate to what octane level exactly? Also, isn't alcohol bad long term for the fuel system seeing how Lexus doesn't recommend over e15?
Sorry I know it's alot to unpack, I see everyone praising blending but no hard data like final octane level or dyno results. I can see blending e85 with 91 to raise the octane level to 95 and have it be cheaper than 91, if that's the main purpose then I get it, but if I blend e85 with 100 octane, what would that even mean? Can our ecu even account for that?
Thanks in advance everyone!!!

05RollaXRS

I would stay away from Ethanol blends unless there is a specific tune done for it. Ethanol on stock tune can potentially damage the engine over the long term. The OEM tune is not designed to handle more than 10% Ethanol content, which is what typically gas stations these days have.

Octane 94 is what I use on my RCF and definitely, there is a pretty noticeable difference between Octane 91 and Octane 94.

DrElvee

Agreed Rolla! What do you think then, try 100 octane? It costs me literally the same as 95 octane and they are both unleaded and %10 ethanol. I'm just wondering if now, going from 95 to 100 will be any noticeable difference.
but yeah, I'm more of a safe than sorry kinda guy that's why I asked, and since in CA all our fuel is already %10 ethanol, I don't think that extra %5 ethanol will make any difference if I were to stick within Lexus guidelines of %15 eth max

05RollaXRS

Octane 100 should be fine as long as they don't put more than 10% Ethanol content on it. You can try it out and see how the car feels. I have never gone above Octane 94 because Octane 100 is considered race gas and only available in select remote areas.

LoSt180

Ethanol requires more fuel delivered to maintain proper AFRs. You can get away with an E30 blend because the ECU will adjust the fuel trims +20-25% without triggering a check engine light. There's a few calculator apps to help you blend 91/93 and E85 to maintain the correct mix. Fill a tank using full E85 without a tune and your car will basically go lean. Lean = detonation = knock = engine damage.

The benefits of running E30 (or full E85) are that you can increase timing. On the stock ECU, the boost is pretty minimal. Might help you bump up the KCLV on your engine, and cars driven at higher altitudes will actually gain some performance back.

Tuning is where you'll see E30 or E85 really shine. Fueling targets are fixed and then timing is advanced, meaning more power. Wish there was a way to add a flex fuel sensor to the ECU, since E85 availability is spotty around where I live.

DrElvee

Oh wow! That's some good info, thank you! So me running an e30 blend on my 2020 won't be any more beneficial than 95? Or what do you think (without a tune) what's better, 95-100 or e30?

LoSt180

I can't really speak to 95-100 being better or not. That stuff is even more rare and expensive that it's not really worth my time to seriously look into using. I think it's only available at the race track around here.

What I would suggest is getting an OBD2 dongle and taking data logs to see what works best. In simple terms, basically looking at lambda, kclv, and timing advance.

DrElvee

I've been meaning to get one for a while, my wife's lexus has been getting excess amount of sulfer smell and dealer is saying that's normal. Definitely not normal.
what didongle do you recommend?

DrElvee

And yeah I just got lucky that I have a gas station selling 100 at the pump near me. It's $10 a gallon, but our 91 at shell or chevron is $5 anyway, so when I mix 91 with 100 to make 95 it comes out to about $7 a gallon. Thats a $2 per gallon difference and since I don't daily the car I figured that's an acceptable amount for the extra smiles per gallon lol. My main thing is to make more power safely, and I read without a tune, any ethanol blend has a substantially high % of damaging your motor if mistakes are made

DrElvee

So I just ordered the Tactrix openport from their website so I can see live data. I mainly want to see the differences between 91 vs 93 vs 95 vs 100 and find the lowest octane with the highest power/advanced timing. Essentially, if 95 and 100 have the exact same (or very close) outcome, there's no point to run a $3 a gallon more 100 vs 95. But, to be sure that there even is a true difference between 91, 95 and 100, I'd need start back at 91 octane right?
Because I definitely feel a differences between 91 and 95, should I more look into the difference between 95 and 100? And not even go back to 91?
I don't daily the car so price of fuel is *almost* a non isssue, it's more the drive there with canisters that's the hassle, but smiles per gallon is what I'm trying to maximize here.
What do you guys think

RandallNYC

Doesn’t ethanol ruins the high compression fuel pumps?

buister

iTrader: (1)

I recommend that you check out this thread about using the OBD Fusion app to read the Toyota-specific data.
https://www.clublexus.com/forums/is-...-60-oh-my.html

I have a Veepak OBDII dongle. I paid $10 extra for the Toyota extension with the OBD Fusion app on my iPhone. It's amazing how much data you can get from this app. I must say literally hundreds. There is engine temp, oil temp, transmission temp, VVT angle, ignition advance angle, emissions stuff and so so many things that you never heard of. For playing around with the fuels, all you need to monitor are KCLV, knock feedback value, short & long-term fuel trims, A/F readings. The higher the octane the higher KCLV you'll get.

If you're still thinking of mixing E85, you should read this thread:
https://www.clublexus.com/forums/is-...nd-of-e85.html

I've been running E25-30 and I like the way the car runs with the Delicious Tuning tune that I got. The tune is not really for E85. It just has more aggressive timing, so the high KCLV I get from the blend really helps. Since you brought this up, I think next time I will fill up with 95 octane and compare it with the blend I've been using.

Yri

It's common knowledge that ethanol is highly corrosive and not running special equipment can and will cause damage. I've heard of guys running E85 with stock rubber lines on different forums and having the rubber lines begin to crack and weep. If you want more octane, buy quality octane booster and give that a shot, or just buy race fuel. There also comes a point when octane does no longer provide power on a stock tune. 95 is probably your best bet, 100 might give you just a tiny bit more power but nothing truly noticeable

DrElvee

yes, thats why I was asking about e85 and wanted to see real world result of pros and cons. I'm currently running 95oct and have easy availability to 100 octane at $10 per gallon so I am definitely not going to risk running e85. Mainly interested in the differences of 95vs100 now

definitely let me know! I would love to compare and contrast

that's my best educated guess as well. However, 2ur compression is 12.3:1 so on paper *technically* 100 should be the preferred fuel. That's why I want to data log. I want to see if the increase in octane correlates to increase in power. I honestly think there is good chance that it will have a substantial increase. If from 91 to 95 (completely hypothetically) had an increase of 10 hp, then my guess would be that 95 to 100 will have additional 10hp simply because of the 12.3 compression and timing. But I'm not a professional so that's just my guess. I will However be looking to dyno the car, so I might just end up going to 91 first and see what the increase is.

BretTravis

In my area Tulsa, OK E85-$2.29 89-$3.30 91-$3.60

Mixing 4gal of E85 with 13.5gal of 91 yields 95-96 at a lower cost than a full tank of 91. Performance result: 2-5 mph increase in top speed reached on front straight.