07 TL auto, no mods. oh, trans cooler.

I went to Hamilton Honda on Aug 2nd for the timing belt special + $75 adjuster, got the valves adjusted,(boy, it's so quiet. i THOUGHT the valve noise was injector noise) and tensioner, idler pulleys replaced for both timing & drive belt (bought the 4 pulleys from hondapartssales)
for 800 (plus tax).

they told me the 389 TB special is good till the end of August.

anyway,

since timing belt, the car had 3500 miles since the TB job and,, (yes road trip)something strange happend with mileage.

it went down to 26 (with 200lbs), but it was Penna + NY mountains so it's understandable..
then 28 with 450lbs, i was sleeping, my friend was doing 80-100mph -_-
then 27~28 going Trans Canadian Highway. (cruise set at 70mph GPS, which was exactly 2000rpm)

On the way back with the same load (450lbs), i could go more than 200miles with half a tank (according to OBD-connected fuel monitor, half a tank is 6.2 gallon-ish and gas station pump says it's about right too.)

then at the next fill up, distance/gallons turned out to be 33.5
(this tank, departure and arrival altitude was the same so it's definitely not downhill mpg)

during the road trip, i've noticed all my XM presets are gone, and thought ,hmmmmmmm maybe the mechanic actually disconnectd the battery doing the TB job.

now with stiffer rear suspension + class 4 hitch welded to bumper rail i'll be happier than truck owners (half jk but maybe)



so the questions are

1. which one affected mpg? ECU reset/valve adjustement/TB job/5hole amsoil S2000 oil filter??? (doubt the filter lol)
** canadian premium is 91octane and my home is 93. would 91 make it more "efficient" say, push detonation to the limit? but the timing advance gauge was 35-41 no matter which gas.

2. why does speedo & GPS say 70mph but trip comp says 68mph?? (btw it said 35mpg lol little too happy)

wow good report! maybe your old timing belt was really worn and the engine use less stress now with all the new parts therefore better gas mileage. just a guess though, anyway enjoy your TL for the next 100k miles.

definitely enjoyable with this (premium)gas sipper TSX guys WILL be jealous hahaha

The timing belt does not get worn out enough to where it would cause a decrease in performance or gas mileage so that is a moot point.

It would be destructive if your timing belt was worn to the point that it was causing the valve timing/ignition timing to be fudged up.

Drive it more, then make a conclusion about MPG.
I put on a Jpipe 2 weeks ago and I won't comment about my MPG until at least a month

hmmm how many more miles would i need?

It goes back to math. If you want to make a conclusion about something like MPG, you need a large enough of a sample size to account for your variability in your driving.
The more data points you have, the better to support your conclusion.

For a random sample size and quick and dirty idea, start keeping track at the next fill up and do this 10 times.
That will give you 10 mpg values from 10 fillups. You can then average those etc.....
I've probably filled up 4 times now since the pipe, but I've also been resetting the ecu etc... so it'll be a while before I make a conclusion about MPG from the Jpipe

having the valves adjusted properly makes a big difference as it can allow a bit more air into the cylinders for more power! You'll notice as soon as the spark plugs and such get situated your MPG will go up. It seems that with more miles these engines are getting better and better!

Oops, I missed the part in the OP where he said that he got the valves adjusted.

Valve adjustment wouldn't make that much of a difference no matter how far out of spec they were. And I doubt they were out of spec by more than 0.001" anyhow. Ask your service manager for details on valve lash measurements before adjustment.

As far as noise reduction, hard to know. Again, unlikely that any perceived reduction in noise is due to the valve adjustment.

Oh. I should make myself clear.

Noise as in all cover off&hood up idling noise

follow up in 3 more fillups
32.6avg
33.8avg
31.9avg(KY, TN mountains) - trip odo was at 410mls when low fuel light came on

some guys at ecomodder said it could've been one of the pulleys that were replaced had bearing that robbed power but, really? i don't see it.

how much did they charge you for valve readjustment?

post up the avg MPH with those #'s

Who cares about MPH. He raised his MPGs. Good work and hats off to Hamilton Honda again.

For some reason since changing to F14's and Nitto Motivo tires I lost 5-6 MPG. Went from like 32 highway consistently at 70-75 to 26-27. :/ Can't be the F14's cause it is lighter, but I don't think the Motivo tires would drop my MPGs 5-6. :/

I've got the motivos too and have no such change.

289+tax

i personally don't like the avg MPH on trip comp because even though i've been crusing 70, and stop 4 times a tank to pee, it goes down to 58, looks like i cruised 60mph non-stop so. yeah i never changed my cruising speed at the original 70.


are you making fun of how there's no way my MPG could go up from timing belt job lol

^^ timing belt yeah, valve adjustment no.

I honestly doubt your valves were that out of spec that it would cause a decrease in MPG. It should be negligible.

Like I said above, if your timing belt was jumping, you would have known. Timing belts don't have an "in-between" in terms of proficiency. You would know if it was slipping/jumping.

did you really get that from my post? I was just saying good work or good job in getting a better MPG. lol

oh LOL thanks, i'm a little crazy these days

Wait...is this your own math or are you judging this by what the computer says? LOL

Oh *smh* people WOULD think i'd post MID MPG lol

If you meant OBD2 hookup computer yes. It's never been off more than 1% of my hand calculated mpg with distance/first cutoff.

Btw MID said 35-36 lol

MID is pretty accurate.

yes it is pretty accurate in Range(distance to empty)

oh, i just remembered a question, do you know why when GPS &speedo says 70mph, but MID reset gives me 68? always -2

Reset your ECU and see if it still pops up wrong

A "worn" timing belt can't affect engine "stress", whatever that means. You could make the argument that it loosens up over time but that's not really true either. Timing belt either works or doesn't work. No inbetween.

Exactly. Not enough data to draw a conclusion yet.

A valve adjustment can make a difference if it's so far off that you have valves that are not closing all the way but you would end up with a misfire long before a valve adjustment could affect mpg.

More air in= more power, more power = more fuel used, the same as giving it more throttle.

A pulley with a shot bearing, I mean really shot won't absorb even 1hp. If it did, the heat would cause total failure. If it takes roughly 50hp to maintain 70mph, you can see how a pulley won't make a measurable difference.

Ignoring the mph would be like driving downhill only and congratulating yourself on better mpg. Average mph is one of the only things that matter when attempting to maximize mpg. It is the single largest influence and larger than every other influence combined.
Did you check the average mph before and after?


The only way to accurately claim a mpg change is to drive both directions as many times as possible under the same conditions. Driving one way to a destination and drawing a conclusion is invalid. One or two trips is invalid. You want to have hundreds of miles of routine driving if you want to see if a mod or change made a difference.


MID mileage is extremely accurate. Hand calculations do not begin to approach MID accuracy until many tanks have been run through. There are so many variables, mountains, load changes, speed changes, etc.

My car will barely get 26mpg on the 45 mile drive to work. It gets mid 30s easily on the way home. I watched the GPS once and there's an inperceivable altitude change. This is why one way info just doesn't work.

MID MPG statements without accompanying MID MPH data is suspect to lots of subjectivity.

I have noticed a huge correlation of MPH to MPG. This happens when I enter my data into www.fueleconomy.gov. I enter text like 'MPH=xx' and then I get one or two auto-completions in the browser field with MPG=yy+/-1. Often it is the exact value calculated from gallons used and distance.

There's a reason Acura provides the MPH data along with calculated MPG- I suggest we all refer to it with as much enthusiasm as the estimated MPG value.

Recently drove from California to Colorado - been meaning to post this in a new thread, but this seems like a great place for it. Was pretty happy with the 33 mpg. For reference, I'm a 6MT, at 95k miles, factory timing belt and other major engine parts, using Mobil 1 Synthetic, and generally keep things in good shape. Rolling on 17" stock 2007 rims, and Continential Extreme DWS tires.

When I meant ignore, I was trying to say that everyone is bashing his numbers instead of giving him the benefit of the doubt.

And since you're here IHC, quick question. I changed from G37 wheels and Hankooks too F14 (8 lbs lighter each wheel) and all season Nitto Motive (from reviews and other people here they don't lose MPGs instead they saw gains) and lost literally 5-6 mpgs. Each trip was 400 miles. Average MPH was 70. Before I use to get 32+ (at least)MPG. Now I get 26-27. I drive 75. Before I get 31-33 MPG, now I get 25-26. I drive 82 MPH I get 24-25 when I used to get 29-31. I don't know what could be the issue. Tires are all 36PSI. Saved 32 pounds from wheels which is equivalent too 320lb lost. How did I lose MPGs... that badly? And of course I fill up 93 octane and sometimes put a gallon or so of 100 octane every couple thousand miles.

yes :/ resetting again soon due to my stupidity in ruining "driving history" on ECU


@110,000mls, still getting the awesome MPG

maybe intake was toooo lose? haha i don't know

pulley : thought so

agree MID is very accurate, but it's been DUMB DUMB it's been saying i have 470mile range when i fill it up, before timing belt. i think it must be the ECU reset.
(now i get very accurate Range and avg mpg)



i'm not IHC but maybe too light wheels have not enough spinny momentum to keep the car rolling? at least he'll see this now




so there's no chance of italian tuneup burning carbons off of O2 sensors?