[zro26t]

Went to the dealership yesterday to order a 2nd full mask for one of the '07 AV6s in my driveway. While there, I ran into the sales guy that sold me both cars. Long story short, we got on the topic of better performance from the AV6. I told him that the auto trans seems to lack quickness in the down-shifting dept. His response to that was use a higher octane gas, and you'll notice better performance and quicker shifts.

:lmao:

After I laughed my butt off inside my head, I said I'd think about it. Now, being a self-taught tuner (using HPTuners for tuning my truck), I started to ask him how in the world would increasing octane affect shifting. I haven't a way to access the AV6's computer, but GM's trans settings are in a totally DIFFERENT table, and not directly associated with spark tables.

Question(s):

1. Are the AV6s optimized for 87 octane, or higher?
2. Are there any tuning software sellers that offer a software & interface package for the AV6s.

Thought I'd share my experience from yesterday. :thmsup:

 

[Peniole]

Search the forum on the gas octane issue, it's been discussed to death. There is an interview with a honda engineer when the J30 came out and he did say running on 91 will give you a 10HP boost since the car can adjust timing according to the gas you're using, whether that would affect shifting dunno :dunno: . That said it is advertised to run on 87, it can't hurt to see if you notice a difference on premium. The K24 no such concrete evidence but they do have the same capacity to adjust timing so theoretically possible.

 

[zro26t]

Well, I don't doubt the increase in HP numbers. As with most computer controlled vehicles, there's a primary and secondary spark table. The computer will start out using the high octane table first, then switch to run the low octane table if knock is detected while using the high octane table.

Most domestic performance tuners will negate the switching of these tables by copying the low octane table to match that of the high octane table. Better said, Copy the HO table's values, and paste them into the LO table. This'll eliminate the use of different spark values used when the computer switches between tables (driver won't notice).

I just doubt there's any credit to the sales guy saying that higher octane usage improves shifting. On a GM application, I can modify shift properties for greater performance, by tapping the tow/haul button.... or set different properties based on throttle position (in %'s).

 

[hiddengamer7]

Yea, you will notice a difference with using higher octane gas, but it wont change the shift points or quickness of them, but you will still get faster acceleration due to the 10 extra ponies

 

[Accordlover]

Most domestic performance tuners will negate the switching of these tables by copying the low octane table to match that of the high octane table. Better said, Copy the HO table's values, and paste them into the LO table. This'll eliminate the use of different spark values used when the computer switches between tables (driver won't notice)

Speaking of domestics... Ford and Mercury don't want people hot rodding in their Sables and Taurus's. I put premium gas in the Sable one day, and the check engine light came on, I had to get the dealer to reprogram the car's computer just becuase of that, and when I was ready to go back to regular he had to do it again!(and at an astronomical price nonetheless) :nuts: Not the best of ideas if you plan to play around with your Taurus rental car anytime soon.

 

[zro26t]

Speaking of domestics... Ford and Mercury don't want people hot rodding in their Sables and Taurus's. I put premium gas in the Sable one day, and the check engine light came on, I had to get the dealer to reprogram the car's computer just becuase of that, and when I was ready to go back to regular he had to do it again!(and at an astronomical price nonetheless) :nuts: Not the best of ideas if you plan to play around with your Taurus rental car anytime soon.

Taurus RENTAL?!!! :lmao: I'm sure switching octanes caused the ECU to notice the change in fuel ignition, and the fact that there may have been unburned fuel being pushed through the exhaust system. The o2 sensors will notice the difference, and report it to the ECU. Now... depending on how Ford's/Mercury's engine management systems are designed, they may only report that change as a potential problem, and not attempt to correct it by reverting to a secondary table.

That's why I like the way GM designs their engine mgmt systems. The computer starts with high octane spark values, then switches to an optimized table for lower octane fuel (depending on detection of engine knock... also known as spark without the presence of adequate amounts of fuel).

BTW... for engine code references (or to get 'em deleted), go by Autozone, and ask 'em to show you the code using their scanner. Most of the time, they'll even delete the code from being active.

 

[Trip]

For what it's worth, here's the USA today article where this quote came from:

"The Accord V-6 ratings assume regular-grade fuel, and Honda will market it as a regular-fuel engine. But — pssst — it's good for another 10 hp and 10-plus lbs.-ft. on premium, acknowledges V-6 engineer Asaki."

USA Today

 

[Succinct]

That USA today article about the +10 hp w/premium fuel is from initial launch of the 7th-gen back in 2003. No one knows how applicable it is to 2006+ V6s. I tried a tankful of premium in my 2006 AV6 and really couldn't tell any difference in my butt dyno, so I'm sticking to regular as the owner's manual specifies.

Maybe this summer, when the engine is more prone to ping (which is all octane rating is - the fuel's resitance to ping), I'll try another round of premium to see whether it helps in hot weather. I'd expect to see at least some difference then.

 

[zro26t]

10hp isn' noticeable on a butt-o-meter. However, 15ft/lbs of torque is slightly noticeable. I noticed a good bit of decrease in torque from GM's 5.3L down to the 4.8L. Off the line launches are more sluggish with the smaller 4.8L.

Anyhow... I'd have to see the differences on a dyno to tell. That and maybe a 1320ft comparison.

 

[kevinhing]

is it even safe to run premium on a v6 set to run on 87 octane? that would be nice to have a little more torque and horsepower, but does premium really provide any other benefits, such as increased gas mileage in the AV6?

i just got my car and recently filled up with some crap ass 87 citgo in the tank. my car runs fine, but i will probably experiment with 91 or 93 later on to see if these hp and torque claims hold any truth.

this will probably be after my first oil change. no sense running premium without a full synthetic oil in my engine.

 

[AccordEd]

I haven't tried premium yet. Anyone have first hand experience that can honestly say there is a noticeable difference?

 

[Accordlover]

is it even safe to run premium on a v6 set to run on 87 octane?

On the J30 V6 it is. Other cars will react differently.

 

[ken972]

I recently filled up with 3 tanks of 93. There is a noticeable difference in HP but I suppose it isnt a big deal. Im able to pass easier and maintain speed going up hills...the car doesnt seem to even act as if it is going up a hill. The casual driver may not notice....but im sure every one here drives sprited and would notice the difference. Ill do it in the future when I wanna splurge...heck i might just keep doing it.

 

[john07ex]

First thing..
YES its the car salesman who said it. So no its NOT true..LOL

there all liers.

 

[zro26t]

First thing..
YES its the car salesman who said it. So no its NOT true..LOL

there all liers.

I used to be a sales guy (pretty good one) during my latter years in college. I couldn't do what other sales guys do... say anything to sell & make a buck. I was in it for the REPEAT business. I just love talking to sales guys then laughing at them while I tell them they are WRONG. I don't do it often enough tho. Gonna have to change that.

 

[Succinct]

is it even safe to run premium on a v6 set to run on 87 octane?

Since octane rating is nothing more than a fuel's resistance to knock/ping/pre-ignition, it never hurts to run premium on an engine designed to run on regular. Running regular on an engine designed for premium is what you must avoid.

Knock/ping tendency is a function of compression ratio, combustion chamber (CC) design, engine operating temperature, and timing advance. Engines designed to run on regular usually have a compression ratio and CC design such that optimal timing can be obtained on regular, so using premium won't hurt, but it will be a waste of money.

However, many engines designed to run higher octane usually have sophisticated knock sensing and timing advance systems, so more aggressive timing advance can be run to increase torque on premium fuel, but timing advance will be electronically curtailed when running lower octane fuel (decreasing torque/hp).

The AV6 engine is probably somewhere in between the two examples above - it is near-optimal on regular octane, but there is enough "headroom" in the timing advance curve and it has sophisticated electronics such that a few HP can be wrung from the additional couple of timing degrees advance allowable with premium.

As mentioned, I saw no noticable increase in power by switching to premium in the winter, but may try again in Summer, when hotter temperatures increase knock tendency. But one of the reasons I bought the Accord over an '03 TL Type-S was the fact I could use regular fuel. Yeah, it's only 20 cents/gallon more for premium, but I won't spend that if I don't see any power advantage to doing so. :thumbsdow

 

[kevinhing]

thanks for the advice. too bad i still have to wait till i break in my car before i can rev the crap out of it. no sense in running premium at the moment since gas prices are shooting through the roof these days.

the car is plenty powerful on regular, but cant wait until my first oil change when i can switch over to a full synthetic. hopefully by then gas prices will settle down and ill be able to run premium without worrying about the price.

 

[stevencrosbie]

To be honest, Premium fuel is less of a premium now than it was when gas was lower. I've had to switch to premium since I got the TL and I really haven't noticed the monetary difference as its only a couple hundred a year at most.

.20/$3.00=6.667%
.20/$2.00: 10%

Just some food for thought. Break the car in properly.

 

[kevinhing]

yea, no doubt. i dont like to push the car so early in its life. it should be broken in soon, only 200 miles to go. :thmsup:

 

[zro26t]

Break-in period = 500 miles or what?

Bought mine with 518 miles on it, at a lower cost of course. :banana: :thmsup: