So what exactly happens if you run Premium in a 4Runner?

My butt-dyno feels it has more pep in it's step on 91. when I use 87 in socal, it feels bogged. I would show you my butt-dyno shiet, butt you may not want to see it.
 
fkheath said:
Only engines with higher compression ratios need higher octane gas; the 4Runner is not one of those. Thus there will be no difference in power, or fuel economy.

However, it is more important to use Top Tier Gas as recommended by Toyota and shown in the latest owners manuals (TOP TIER™ Gasoline Brands). Top tier gas has more cleaners in it than fuel that is not top tier, thus your engine will be cleaner, on the inside.
Click to expand...

How is Gulf not on that list of Top Tier Brands?
 
I know it seems I pulled engine compression numbers in an earlier post out of thin air. Have a data point worth discussing… sometimes I like to compare brands for the sake of learning what’s out there, I’m not out to prove or disprove anything, so we can compare apples to elephants if it’s cool with everybody else.

The 9.6:1 on mid grade was the early 5.7 Hemi’s compression. I have long been impressed with my 04 Durango’s ability to climb inclines without downshifting. Just maintains speed and RPM, but the engine gets a little louder. I never knew the mechanics behind what it was doing, though.

One day, I hooked up one of those little ELM327 scanners you can pair with an OBD2 app and observed some read outs for timing advance. Rolling into the incline I observed the timing advance sweep from -6 deg to -35 deg. I wanted to compare it to what others may have seen in their Toyotas.

I will test the 4Runner over the same incline as the Durango once I make a trip out that way, and report back. I can even do it with premium vs regular gas.

Here is the rest of the driveline of the Durango, also has a 5AT but way different ratios.

545RFE (has a 3.55 rear)
1st 3.00:1.
2nd 1.67:1.
2nd Prime 1.50:1 (Only used on kickdown)
3rd 1.00:1.
4th 0.75:1.
5th 0.67:1
Reverse 3.00:1.


Sent from my iPhone using Tapatalk
 
Looks like we've switched gears into tune talk. I like it! IMO the factory 4R engine tune and range of self adjusting parameters is VERY good when compared to other trucks. For me it has always adapted quickly to higher performance expectations when fueling with a higher octane. My Silverado was not as snappy, didn't seem to adapt within a reasonable timeframe and couldn't always correct for knock when running a higher octane. A custom tune made the Silverado a performer but that was necessity. I have not experienced that being the case with the 4R because as long as you're selecting 90 octane or above (you desert runners or Rocky Mountain folks may need more) engine management always adapts to perform with ZERO noticeable knock. Right now I prefer not to be locked into using a higher octane like you are with a pre-tuned ECM swap. I'd also like to skip the hassle of loading and reloading tune files that match desired use with a customizable flash setup. For me, it's nice to have the freedom to fuel with the octane I think is best suited to my desired use and let the ECM adapt from there. If I ever do select a tune, I'll pick the one I believe will best manage the areas where the TCM lacks in performance. If a tune provider can show me solid data with improved shift controls especially when towing or expressway driving with the cruise set above 80, take my money!
 
Unless you engine is tuned for a higher octane, benefits will be very little.
One way to increase fuel economy, and lighten your wallet, is to run ethanol free fuel.
Many stations sell it for boating etc, at the pump. It just costs more.
 
Steve40th396 said:
Unless you engine is tuned for a higher octane, benefits will be very little.
One way to increase fuel economy, and lighten your wallet, is to run ethanol free fuel.
Many stations sell it for boating etc, at the pump. It just costs more.
Click to expand...

I agree with this. I've still got half a tank from when I filled up with the non-ethanol gas and I can tell the difference in pick-up although it's small. $5.00gal when I did this two weeks ago. Heck soon it will be the cheapest stuff to get. I hate the whole corn subsidy political mess a nd what that gas does to two strokes.
I realize it's an older thread but these issues are not going away.
 
badattitude said:
Read somewhere it took 3 full tanks of gas to adjust the timing for high octane = about 1000 miles. I do believe in pure gas (no ethanol). Pure Gas is mainly sold as 91 octane around here. Sure, I can't really tell if there is a difference with 91 octane. I don't have data. I also think it helps to use the entire rev range when using high octane. Driving all day at 2,200 rpms is not how the engine adjusts to high octane. The engine wants to rev to adjust timing. This is my opinion. I don't have proof and want that to be noted. 91 octane was $3.44 here today. I don't drive a lot of miles. Using 91 does hurt the pocketbook when traveling, however.

Also - I agree the purpose of high octane is to reduce pre detonation = ping/knock.
Click to expand...

I think this is the mort important thing. LESS ETHANOL. I do not believe that octane has anything to do with ethanol content. 87-91 gas can either be E10 or E15. E10 has less ethanol. Ideally, you would be putting E10 fuel in your 4Runner, regardless of the octane.

So you want, ideally, "top tier" gas that is also E10. I think almost all gas is E10? I think E15 gas is marketed as 88 Octane. I don't know. I'll check my gas station next time I fill up. It's probably printed on the pump somewhere. If your stations have 88 Octane as an option, I'd probably avoid it.
 
Last edited:
You make more power with less octane, if ignition and ecm can make it ignite without pre ignition.
I know that may not make sense, but its how things work.
But I digress.
But, if you have a tuner put more fuel amd timing via ecm tune, you can make more power.
Look at diesels. Very low octane and high compression.
 
2021nightshade4x4 said:
After so many tanks, will the vehicle “attempt” to advance timing a little further?

Curious if there is any benefit to doing this or zero reason to try it.


Sent from my iPhone using Tapatalk
Click to expand...

No performance gain but it does suggest you may be a powerful person in an oil producing nation with money to burn.
 
<a href="https://ibb.co/gws529H"><img src="https://i.ibb.co/ftmhgFB/220512560-342767624210503-1094328951997811285-n.jpg" alt="220512560-342767624210503-1094328951997811285-n" border="0"></a>
 
badattitude said:
I use premium exclusively, 91 pure gas. I believe the Dual VVT does adjust the timing. To protect the engine it takes about 1000 miles of consistent premium gas for the ECM to make the full adjustment. If you use one tank of of 87 octane the ECM adjusts back (retards) the timing immediately and you'd need another 1000 miles of premium to regain the ecm timing adjustment. Im not sure this is 100% accurate but it is what I've pieced together. My truck is fast! I'm getting 18.9 MPGs all summer.
Click to expand...

Are you still running premium at today's gas prices?
 
Premium (Super) Unleaded is the only way to get ethanol free fuel here, and even then only at Esso stations. It hasn't made it able to fly or anything, though.
 
If you always put premium in you can have a URD Supercharger....well that is if they were ever available again. :banplease:
 
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