btu44

This is a project I have been thinking about for a few years now. The goal originally was to get better than 16 MPG. If I could get it up to 18 MPG it would pay for itself in about 30K miles in gas savings. But unfortunately a call to Split Second burst that bubble. They explained there usually no MPG improvement with there MAF conversions. This is because a closed loop EFI system is always maintaining a 14.7/1 fuel ratio. This ratio is important because this were catalytic converter works best.

See page 4
http://www.autoshop101.com/forms/h64.pdf

He also mentioned this is why ‘leaning out’ the AFM settings doesn’t help mileage. The computer will just compensate for the adjustment. He said that if you could ‘lean it out’ generally you loss horse power, which then requires more cruise throttle, which negates any MPG improvement from a lean run. So it looks like a MAF conversion is a HP thing. That’s OK…the 3VZ-E could use it.

Here is my original design.

First on the list is a wide band A/F meter for tuning.

Next is MAF calibrator.
(see first attachment)

The intake system would consists of these parts.

This is the Bosch 028017120 MAF sensor. (second attachment) It has a 70mm (2.75”) output tube. Same as OE AFM. It was used on early 90s SAABs and seems to be easy to get. I sent the spec sheet to Split Second and the engineer said it would work with there calibrator.


I will use a short length of 70mm silicone tube to connect to this adapter of my own design.
(last attachment)


The biggest problem with this adapter is the round ID has an area of 4.7 sq/in. The rectangular opening of the air box side is 3.9 sq/in. I wonder how much this will limit HP but have no way to figure it out.

But I recently found this cold air intake.

http://www.sbfilters.com/toyota-3-0L...ke-kit-75-9006

This looks pretty good and would be easier to make the adapter. It also has a CARB OE Number. But I don’t now how smooth the air flow is exiting the filter. Split Second has a tech article that mentions that the air flow from a pod air filter is pretty turbulent. I would design the adapter with a nozzle to smooth the air flow. But it would be hard to tell if it solves the problem of turbulence through the MAF.

Question for Cali. Smog Techs. How likely would it be to fail visual inspection with this cold air intake, CARB EO # and the MAF, not the AFM installed?

Now for the price and it isn’t pretty. Just the hardware it is $1065. This is using a new genuine Bosch MAF at $200. A used one on eBay is around $75 but it would be one more tuning variable. ‘Is this used MAF outputting a good signal’? After tuning, I could probably sell the wide band A/F meter to recoup some money.

Then there are several other costs. Getting the injectors serviced with an intake gasket would add about $160. I want to make sure I’m not tuning around possibly bad injectors. Also during tuning, the O2 sensor is disconnected to run the engine in open loop mode. This can be hard on the catalytic converter. So I would have the cat removed and a temporary by-pass tube installed. Then after tuning have the cat reinstalled. This would probably add around $100.

That gets the total right about $1300 or so. About the cost of dual transfer cases or a real suspension lift.

What do you guys think, good or bad? Any design improvement suggestions?

Thanks

PS: I apologize if this is a difficult read. I’m not good at describing things.

aa1911

iTrader: (1)

I would put the $1300 into something else but that's just me. 1300 will also get you a brand new remanned 3vze engine!

plus, if you're netting 16mpg's with those tires and that setup, consider yourself lucky already. You're just not gonna squeeze much out of this thing unless you drop some serious $$.

scope103

Average price of gas in the US is about $3.78. Raising fuel economy from 16 to 18 mpg means you'll recover your $1,300 in only ... 50,000 miles. Of course, that assumes your time is worth $0.00/hour. And that all of those parts will last at least that long.

In my experience, slowing down from 70 to 65 mph will save more than 2 mpg. Might save your life, too.

There are lots of people who will tell you they know more about Toyota motors than the engineers who built them, and they'll sell you lots of stuff so you can see for yourself. If you're into that, well, it's your money.

btu44

I know...$1300 is way to much for a unknown, possibly no improvement mod.
If I forgo the injector cleaning, buy a used MAF, and use the stock air box. That gets the price down to $650 or so.
I consider 16 MPG OK. I probably get that because I drive no faster than 68 MPH and my other car is a Hybrid. I one time drove 75 MPH heading home from the Mojave desert and only got 13 MPH. Haven't done that again.

As far as gas prices here in the Los Angeles area. It been over $4 for a while now and lately sitting at 4.60.

I'm not thinking I know more than the Toyota enginners. I'm just upgrading to the current technology. The AFMs has few negatives that MAFs don't, mainly restrictive to air flow and mechanical wear.

donomite49

i just got back from a road trip,19 mpg, driving from 70 to 80mph,
pullin a little less than 1000 pounds, bikes and trailer.

my 3.4 will pull hills with the v8's all day.

MudHippy

If you think your AFM restricts too much air flow, then why not use a larger one? That's why Toyota used larger AFMs on their other "high performance" 3.0L engines(i.e. 3VZ-FE, 7MGE/TE). Which you could still tune however you wished. Oh, and on that note, if it doesn't matter how you calibrate the AFM(since the ECU will compensate for it). Then why is it calibrated a certain way at the factory, and then sealed as to prevent anyone from messing with it? Gee, you'd think it might actually be of some significance as far as how the engine runs if they went to that much trouble. Or would that thought not occur to you(rhetorical)?

And how exactly is an early 90s SAAB MAF the current technology?

FYI, depending on how you drive, you're either in closed loop more often than open loop, or in open loop more often than closed loop(more likely). Since closed loop is only used whenever the engine is warm and; idling, "cruising", and/or under a "light" load. Whenever those conditions aren't met, the ECU uses open loop(which can be quite often, unless you drive cruising down the highway under a light load, or at idle speed, ALL THE TIME...which NOBODY does).

See pages 1 & 4: http://www.autoshop101.com/forms/h58.pdf

Hint: Want better MPG? Run higher octane fuel. It's fool-proof(you can't NOT get better MPG than regular by running mid-grade or premium).
Since when is this thread about a 3.4?

btu44

Yes I agree a larger AFM is an option. But of the few I've seen on-line, they were not a very clean installation, IMO, and did not get the impression it worked all that well.

Is not MAF used on most gas powered vehicles currently?

About closed or open loop, I'm not sure of the point your trying to make. Are you saying people drive under heavy load significant amount of time.

I think a majority of the time is closed loop. During freeway cruise, I'm at 1/4 to 1/3 throttle. I would say this is a light load.
If I may suggest, see for yourself.
Go to autoshop101 > ODB > Diagnosis. Try To Use the VF Terminal to Confirm Air/Fuel Ratio.

When I did this test I ran wires from the terminal block to inside the truck and hooked up the meter. It was clear while driving when the EFI was in closed or open loop. Only time I saw open loop operation was above 2/3 throttle.