injector service off car. worth it ?

Hachiroku wrote:
>
> OK: 27-29MPG with the Mazda running Ethanol-laced gas, 23-25 with
> 'real' gas from Vermont.
>
> 29-31 MPG with the Scion on E-10, 27 with 'real' gas.
========

Now I've heard of different weights of oil improving your gas mileage,
like switching from 5w-30 to 5w-20, but I'm really not familiar with
different brands of gasoline improving your mileage by 2 or 3-plus
miles per gallon :-)

Plus I'm sure you know that it's notoriously difficult to accurately
assess your MPG's between tankfuls as driving routes change between
tanks, and so do weather conditions and driving styles.

By the way, I've read that switching to 20-weight oil from 30-weight
really isn't going to save you much at the gas pump. Your mileage
might improve one-half of one percent. So say, if you get 400 miles
on a tankful of gas, you'll eeke out an extra 2 miles. You'll
travel 402 miles on a tank, instead of 400. All the while, you may
have been using a weight of oil not spec'ed by your manual.

If your manual specs 5w-30, it can be a great idea to switch to
0w-30 under the right conditions, but I'd be hesitant to switch to
a 20-weight oil just to save 6 dollars a year.

Hachi, keep us updated on your gasoline brand experiments :-)

On Fri, 20 Jun 2008 07:07:06 -0700, Built_Well wrote:

> Hachiroku wrote:
>>
>> OK: 27-29MPG with the Mazda running Ethanol-laced gas, 23-25 with
>> 'real' gas from Vermont.
>>
>> 29-31 MPG with the Scion on E-10, 27 with 'real' gas.
> ========
>
> Now I've heard of different weights of oil improving your gas mileage,
> like switching from 5w-30 to 5w-20, but I'm really not familiar with
> different brands of gasoline improving your mileage by 2 or 3-plus miles
> per gallon :-)
>
> Plus I'm sure you know that it's notoriously difficult to accurately
> assess your MPG's between tankfuls as driving routes change between
> tanks, and so do weather conditions and driving styles.
>
> By the way, I've read that switching to 20-weight oil from 30-weight
> really isn't going to save you much at the gas pump. Your mileage might
> improve one-half of one percent. So say, if you get 400 miles on a
> tankful of gas, you'll eeke out an extra 2 miles. You'll travel 402
> miles on a tank, instead of 400. All the while, you may have been using
> a weight of oil not spec'ed by your manual.
>
> If your manual specs 5w-30, it can be a great idea to switch to 0w-30
> under the right conditions, but I'd be hesitant to switch to a 20-weight
> oil just to save 6 dollars a year.
>
> Hachi, keep us updated on your gasoline brand experiments :-)

Hmmmm...why do I get the impression I'm being toyed with here?

One thing I do know: Particularly on my long-term cars (1980 Corolla SR5
and the GTS) it was easy to watch trends with my little notebook. The SR5
got 33 MPG in the end, and the GTS averages about 36. The 80 had a 1.8
Carbed engine and the GTS a 1.6 TC injected engine.

I still don't really have the tC dialed in yet. I don't drive it enough.

But, I drove the car in Vermont the first year I drove it, and I did
notice an increase switching from Shell to the Ethanol fuel sold in Mass.
About 2 MPG consistently.

However, I also had my Grand Voyager and the LHS at this time. The Gr
Vger had a pushrod 3.3 liter and the LHS had an OHC 3.5 liter: the LHS
also suffered (~2 MPG) on Vt gas, while the Vger was unaffected (27 MPG
overall).

BTW, I use Shell and Gulf. Gulf is the 'lowest' brand I will put in my
car, but it seems to work well. Now, ~15-20 years ago I was using Mobil
in the GTS, and it developed pre-ignition. I ran two tanks of Techron and
switched to Chevron and Amoco (when we still had them here) and the
problem stopped.

C. E. White wrote:

>
> You are ignoring the fact that the throttle position sensor is a very gross
> indicator. It doesn't supply the fine sort of data that would be needed to
> cause the effects you are suggesting.

I'm not ignoring it, I'm just pointing it out as a potential source of
skew- which it is in some cases. And I said it isn't large.

>Take a look at a shop manual for a
> Toyota

No thanks. I don't do Toyota.


>> Of course the dirty air filter will reduce peak power available, and it
>> will still cause the mixture to be significantly rich during open-loop
>> operation where the MAF sensor is ignored.
>
> The MAF sensor is not ignored during open loop mode. The O2 sensor is.


Yep, my bad. Speed-density systems do have a limp mode in case the MAP
sensor fails, in which case the whole system is run on nothing but the
TPS and a look-up table and that's what I was thinking of- although
that's an aberrent case and not really relevant to the discussion. Gotta
say, though, it works surprisingly well in that the engine will run and
get you home. I assume decent MAF-driven systems have a similar
fail-safe mode.

Hachiroku wrote:
>
> ~15-20 years ago I was using Mobil in the GTS, and it
> developed pre-ignition. I ran two tanks of Techron and switched
> to Chevron and Amoco (when we still had them here) and the
> problem stopped.
========

Now that I can believe :-)

On Fri, 20 Jun 2008 08:17:32 -0700, Built_Well wrote:

> Hachiroku wrote:
>>
>> ~15-20 years ago I was using Mobil in the GTS, and it developed
>> pre-ignition. I ran two tanks of Techron and switched to Chevron and
>> Amoco (when we still had them here) and the problem stopped.
> ========
>
> Now that I can believe :-)

Dude, like I said, I keep a little black book in every car, with oil
changes, repairs, maintenance, and fill ups.

If I change something I can see the effects, if any of the change.

For some reason, it doesn't work with the Supra...

On Thu, 19 Jun 2008 14:35:02 -0500, Steve > wrote:

wrote:
>
>>
>> A DIRTY AIR FILTER WILL NOT AFFECT NORMAL DRIVING FUEL ECONOMY ON
>> TODAY'S MAF (Mass Air Flow) sensored vehicles.
>
>Yes and no. If the MAF were the ONLY sensor that affected mixture, then
>the above would be true. But the actual fact is that mixture is set by a
>combination of throttle position, MAF, O2 sensor, and other parameters.
>When the air filter gets extremely dirty, the throttle will have to be
>cracked open more than "normal" to get a particular power from the
>engine, so the MAF and throttle position sensors will "disagree"
>slightly, meaning that the calculations the computer does to determine
>the fuel injector duty cycle may be slightly skewed.
>
>So there IS an effect, but its probably too small to measure in
>real-world conditions where changing temperature and humidity (among
>other things) would easily mask the fuel penalty.
>
>Of course the dirty air filter will reduce peak power available, and it
>will still cause the mixture to be significantly rich during open-loop
>operation where the MAF sensor is ignored.


Open loop is usually VERY short. On my car it's about 20 seconds.
(80F)

>
>And speed-density systems (MAP sensor instead of MAF) will be affected
>differently than MAF systems.
>

Gosh Tegger, you need to try www.dysonanalysis.com services and allow me to prove your cynicism misplaced! We have a TUNER service that directly measures combustion dynamic of any IC engine. As far as identifying chemical constituents in fuel and oil we absolutely can. I ran the R&D chemistry lab at Cummins engine company. In addition to engine development and testing we correlated oil and fuels analysis of just about any IC engine imaginable. I also formulated lubricants and tested filters for fuel , oil and air. After 37+ years we do exactly what you say we can’t!
At YOUR service with science, Terry