taimysho0

hey if i drive in 6th gear when going 45mph on the regular streets am i saving more gas or should i just stay in 5th? thanks

on a side note, i took my car to honda for 3rd gear grind issue, they said since my car is salvaged title the warranty doesnt apply. is that true? thanks

dube_fa5

i dont go into 6th gear unless im on the highway going above 60 mph. i just leave the car in 5th. i heard the 6th gear is just for fuel efficiency but at 45 mph i dont know how helpful it is.

Ross

I use 6th all the time, even going 40ish.

96EJ6LX

If the rpm is under 2000 when in that gear, downshift. O2 Sensors go so quickly when you do bog the engine down. My friends Si had to get that cuz he does 45 in 6th gear. It's not more fuel effiecient*. Honda made it to where your getting about the same when your at 1700 and your at 2700, as long as you don't slam it.

2008fijibluesi

If I'm cruising on a road with a speed limit of 40 mph or more, I'm in 6th. If you're looking to get the best mpg, you should be too.

2008fijibluesi

One of the most ridiculous things I've ever read.

Ross

Anyone else confirm/deny this?

96EJ6LX

It's true. They have put so much tech in the Si.

Ben850

there's quite a bit of truth to it..

if you were @ 2,000 RPM's with the cruise control on, then maybe you will get better gas mileage .. but going down a busy road @ 45-49 mph with fluctuating speeds it's best to be in 5th, with the rpms @ 3,000. I have tested it myself (not an extremely controlled test though) and have noticed a few more MPG.

would not recommend this in your uncles diesel truck though

2008fijibluesi

It's absolutely false. My '94 Accord has 220k+ miles on it. Completely original motor and transmission (except for fluids/filter of course. Also has original o2 sensor. My mother drove the car for the first 185k miles, and she had the thing in 5th gear every chance she had. If you think the Si has no guts in 6th, drive a f22 in it's overdrive gear. Along with not destroying the o2 sensor, we've also seen amazing gas mileage driving this way.

No...you're wrong. More rpm=more fuel. There is a reason that the accelerator is commonly known as the "gas pedal"; because when you press on the pedal, more fuel or "gas" is injected into the cylinder. No amount of tech changes the fact that this is how an internal combustion engine works. Sure, on the short scale, 1700 and 2700 aren't a huge difference, but it adds up.

The Si certainly doesn't "bog" at 40mph in 6th gear, especially with a header . To obtain the best fuel effciency in any car, you should drive in the highest gear that the car can move in without lugging (aka- shuddering, jerking, sputtering, etc.). At 40 mph in 6th, the Si moves along just fine. If you come to a hill you'll need to downshift, but if you don't know to downshift when approaching a hill, you shouldn't be driving a manual car anyway.

Honestly, I've never seen you post in here, so chances are you don't own an 8th gen Si (and more likely an EJ6). I've been driving mine for over 2 years now (not to mention the many other manual cars I've driven for the past 10 years); I know how to get the best mileage out of it. Before I had any mods, I often bested the EPA mpg estimates when I was light on the pedal.

2008fijibluesi

Sorry Ben I have to disagree. I don't know what you were doing but that makes even less sense than just holding steady in either gear.

Many roads around here are 40 or 45 mph speed limits. I usually do about 5 over any limit, and there are many people who can't maintain a speed so I'm regularly fluctuating in the 45-50 mph range, in 6th. I did this before any mods and like I said, often bested the EPA estimates. I have header back and intake now, along with being lowered so I don't know what my mileage "should" be, but I know it's great when I want it to be.

Ross

Side note, I got 25mpg while absolutely caning my Si on the way to CT the other day.

taffy07si

I try to be in the highest gear I can when driving....usualy get gas once a week. I recently went 9 days before I got gas.....so not sure what this tells me but it say's im saving money on gas for sure.

K5^

I use sixth only for 50+ mph.

I try to have the rpms between 2500-3000 when cruising on non-freeway routes.

Ben850

well i am not getting in an online argument, just saying that when i cruise at 3K rpms, i get better gas mileage than if i'm at 2K during city driving.

that is the deal with my scenario which could vary greatly from yours. or maybe i did the math wrong .. not likely though.

Ross

Really?

ajpturbopittsburgh

I looked in the fuel tables in flashpro software I looked at the map tune(you have to, to see fuel tables) stock, tuned. It was the closest thing I could find to a stock calibration and still be able to see the fuel table.

At 2000-3000rpms you are right around the 30 degree cam angle. Then I looked at the low cam and low fuel table at 30 degrees.

@ 3000rmps and if you agree that about 10.9 inches of vacuum is typical cruising load( I know that about 20 is idle and 0 would be wot if not boosted then 10.9 is about middle) it's what I see when cruising on my boost/vacuum gauge. The table for fuel reads 2446 units of fuel.

If you would shift to sixt and go down to 2000rpms and maintained the load of 10.9 inches of vacuum the table shows 2242.

So if you are cruising and not deep into the pedal I can tell you for sure 6th @ 2000rpms is better than 5th @ 3000rpms.

I found a speed chart https://honda-tech.com/forums/showth...ght=speed+gear

So @ 45mph in 5th is 2700rmp and that is 2300 units of fuel.

@ 45mph in 6th is 1900rpm and that is about 2250. These are both at 10.9 vacuum. It's splitting hairs but if you want to be technical, then 6th would use less fuel in this situation

i-VTEC_DOHC

i can't cosign for that. buy my a/f sensor went out hella quick when i got water in my exhaust lol

but i will say that throttle position is everything.

vladd

yeah, the salvage title voids the warranty.

i put it in 6th around 45 for cruising. if accelerating on an onramp or something i'll put it in 6th right around whatever the cruising speed will be.

ajpturbopittsburgh

Right on. Throttle position is everthing. When you increase or decrease engine load, the fuel tables change dramatically. That is why in my previous post I compared columns with the same load values at different engine speeds if you want to compare how many units of fuel the ECU is telling the pump to send.

i-VTEC_DOHC

^yea but that was too technical for some people. to make it easy, it all depends on how far down you push the gas, along with the other environmental factors, and if you have your windows up or down, tire pressure, etc. as far as gas mileage is concerned. but remember that the dbw is real sensitive and even though u think your putting the least load on your motor, you're probably wrong unless you're on cruise control. i've done a few tests by myself comparing the map pressure while cruising at 55 with and without cruise control, and with cruise control, there was less map pressure, which means, less fuel was being used.

2008fijibluesi

Yea...any chance I have, when I am trying to be fuel efficient, my cruise control is on. Max is correct when he says thats the only real way to guarantee the load is constant.

Ben850

exactly what i said in my previous post

ajpturbopittsburgh

The engine load will change when cruise control is on. It doesn't stay the same.

2008fijibluesi

No Ben it's not...you essentially said that if you don't have cruise control on, you should be in 5th, which is wrong.

I honestly cannot believe there is this much debate on this topic. This kind of stuff should be common knowledge. Maybe this is why transmissions are going bad, people driving around in the inappropriate gear? lol