3FE MAF to AFM conversion (1 Viewer)

[Moby]

Long term update: So far this has been working pretty well. I've been slowly getting the tuning dialed. This isn't hard, but it's the first time I'm doing this type of tuning so it is a bit of a learning process for me.

I did hit a problem on a trip to Yellowstone a couple of months back. Turns out that the altitude compensation in the box isn't appropriate for the 3FE and it was running quite rich. Fortunately I had brought the old AFM with me (this was the trucks first long trip with the Split Second box) so I threw it back on.

Split Second was fantastic to work with on this. Within a week of calling them I had a new controller box with a custom dial that adjusts the altitude compensation curve. I recently test drove the new box up to 4,000', adjusted the dial once and was done.

This was also a good reminder of the difference between the stock AFM and the MAF. The engine definitely felt restricted with the AFM back on. Overall I'm also consistently seeing a .5-1 mpg improvement.

 

[Spook50]

Pretty cool to hear. I can't wait to try that conversion on my 62 (it'll come after the ignition job and tranny conversion) and see how much of a difference it makes. Maybe by then the high performance stainess exhausts will be available and I'll have that and a bored out throttle body too

Do you figure it'll always need that manual adjustment for altitude changes, or will it be good to go once it's all dialed in?

Sent from my Motorola DynaTAC 8000x

 

[Moby]

Once it is dialed it is good to go (that's what Split Second told me and that's what I've seen so far). But the normal PSC005 unit won't directly work on a 3FE that sees much driving over varying altitude. It will need to be ordered as a 005 modified with the external compensation control as they did with mine.

 

[Spook50]

Once it is dialed it is good to go (that's what Split Second told me and that's what I've seen so far). But the normal PSC005 unit won't directly work on a 3FE that sees much driving over varying altitude. It will need to be ordered as a 005 modified with the external compensation control as they did with mine.

So the external compensation control will be needed when all is said and done? That's what I was wondering. Not that that's a big deal if it is needed, as long as it can be mounted in the cab

 

[Moby]

So the external compensation control will be needed when all is said and done? That's what I was wondering. Not that that's a big deal if it is needed, as long as it can be mounted in the cab

Oh, I see. There is nothing separate to mount. It is physically mounted to the main PSC005 box under the removable cover. It is a little box about 1/2"x1/2"x1/4" with a tiny screw.

 

[Spook50]

Oh, I see. There is nothing separate to mount. It is physically mounted to the main PSC005 box under the removable cover. It is a little box about 1/2"x1/2"x1/4" with a tiny screw.

Oooh I see. Well hopefully things can be all dialed in so everything is automatic without having to get out and fiddle with things under the hood every time you go over the mountains. Honestly though, if this works as well as yours is so far, it sounds like it'd be worth it.

 

[PabloCruise]

Long term update: So far this has been working pretty well. I've been slowly getting the tuning dialed. This isn't hard, but it's the first time I'm doing this type of tuning so it is a bit of a learning process for me.

I did hit a problem on a trip to Yellowstone a couple of months back. Turns out that the altitude compensation in the box isn't appropriate for the 3FE and it was running quite rich. Fortunately I had brought the old AFM with me (this was the trucks first long trip with the Split Second box) so I threw it back on.

Split Second was fantastic to work with on this. Within a week of calling them I had a new controller box with a custom dial that adjusts the altitude compensation curve. I recently test drove the new box up to 4,000', adjusted the dial once and was done.

This was also a good reminder of the difference between the stock AFM and the MAF. The engine definitely felt restricted with the AFM back on. Overall I'm also consistently seeing a .5-1 mpg improvement.

Do you have a p/n for the controller box with altitude compensation?

 

[PabloCruise]

Do you have a p/n for the controller box with altitude compensation?

I think I see the answer above now.
Any long term impressions/updates?

 

[Moby]

The truck is deceased, see the RIP thread in my signature. But it was working fine up to that point.

 

[PabloCruise]

The truck is deceased, see the RIP thread in my signature. But it was working fine up to that point.

Wow, the plot thickens! I can see I am getting sucked in...

 

[Spook50]

One if these days I'd love to pick up where Joel left off with Split Second and hopefully finalize a legit conversion process and parts list. I suppose I'll have to wait until my factory AFM s***s the bed before I can actually justify the cost to my wife. I put her in charge of the budget

Joel, how close would you guess you were to having the whole conversion finalized?

Sent from OBAMAPHONE!

 

[PabloCruise]

One if these days I'd love to pick up where Joel left off with Split Second and hopefully finalize a legit conversion process and parts list. I suppose I'll have to wait until my factory AFM s***s the bed before I can actually justify the cost to my wife. I put her in charge of the budget

Joel, how close would you guess you were to having the whole conversion finalized?

Sent from OBAMAPHONE!

That would be very cool, sign me up when parts list is built.
I would love to free up a little under hood space w/ the 3FE in the 55.
How much $ are we talking for the Split Second MAF?

 

[PabloCruise]

Took a quick look at:

http://www.splitsec.com/pricelist.html

PSC1-005 Prog.Sig. Cal. AFM to MAF w/Inv. Output $322

But it sounds like we need a modified PSC1-005 to deal with changes in altitude...

 

[Moby]

The whole install was finalized. I had driven it 3 months or so on the modified Split Second box, including up to 4000' elevation and everything was fine. The only thing that I was doing was tuning some of the transition areas to smooth out the signal (you're replacing an analog source, the AFM, with a digital signal source, from the MAF/Split Second box). But this is just part of the tuning process.

The Split Second kit is complete - there is no absolute need to add any additional parts to make it work (assuming you buy the kit and not just the controller). The hardware is self contained and potted for durability. Once you have the unit the work is wiring and tuning - that's it. No additional parts to chase down.

Now I will caveat that a bit and say that I had the benefit of having a wideband O2 that I custom integrated into my onboard PC and also data logged to the Split Second software (you have the option to buy a unit that can take 4 aux data logging inputs). This made tuning sooooo much easier. Split Second's wiring shows how to tap a stock O2 signal but narrow band doesn't give you anywhere near the resolution that a wideband does. Innovate has some very reasonably priced, fast, accurate wideband O2 units - I highly recommend one for this process. Cheap insurance.

I would be surprised if Split Second charged you much if anything for a modified version. They had the new unit out to me in under a week. They were excellent to deal with.

 

[Moby]

Took a quick look at:

http://www.splitsec.com/pricelist.html

PSC1-005 Prog.Sig. Cal. AFM to MAF w/Inv. Output $322

But it sounds like we need a modified PSC1-005 to deal with changes in altitude...

Just to clarify - the units come with elevation compensation built in. However the elevation compensation in the stock unit isn't well matched to our trucks. The modified unit has a small screw that allows you to change the rate at which the unit compensates. It only took me one trip to 4000' to set the compensation correctly. After that I never touched it again - it isn't something that you have to do as you gain elevation.

 

[Spook50]

Just to clarify - the units come with elevation compensation built in. However the elevation compensation in the stock unit isn't well matched to our trucks. The modified unit has a small screw that allows you to change the rate at which the unit compensates. It only took me one trip to 4000' to set the compensation correctly. After that I never touched it again - it isn't something that you have to do as you gain elevation.

So if I'm understanding correctly, what's being adjusted is the rate at which the controller compensates, not how much compensation is done?

Sent from OBAMAPHONE!

 

[Moby]

So if I'm understanding correctly, what's being adjusted is the rate at which the controller compensates, not how much compensation is done?

Sent from OBAMAPHONE!

That is my understanding. Although I think that the other is also correct if considered at any absolute point - because the rate is changed the amount of compensation done at a given point is reduced.

 

[PabloCruise]

The whole install was finalized. I had driven it 3 months or so on the modified Split Second box, including up to 4000' elevation and everything was fine. The only thing that I was doing was tuning some of the transition areas to smooth out the signal (you're replacing an analog source, the AFM, with a digital signal source, from the MAF/Split Second box). But this is just part of the tuning process.

The Split Second kit is complete - there is no absolute need to add any additional parts to make it work (assuming you buy the kit and not just the controller). The hardware is self contained and potted for durability. Once you have the unit the work is wiring and tuning - that's it. No additional parts to chase down.

Now I will caveat that a bit and say that I had the benefit of having a wideband O2 that I custom integrated into my onboard PC and also data logged to the Split Second software (you have the option to buy a unit that can take 4 aux data logging inputs). This made tuning sooooo much easier. Split Second's wiring shows how to tap a stock O2 signal but narrow band doesn't give you anywhere near the resolution that a wideband does. Innovate has some very reasonably priced, fast, accurate wideband O2 units - I highly recommend one for this process. Cheap insurance.

I would be surprised if Split Second charged you much if anything for a modified version. They had the new unit out to me in under a week. They were excellent to deal with.

Joel,
I can feel the tug on me to learn more about optimizing my 3FE, but I am starting from ground 0.
When you talk about the work being "wiring and tuning", what does the tuning consist of?
Are we talking plugging in a lap top and data logging air-to-fuel?
Right no all I have a is a 3FE w/ stock ECU sitting in my little Piggy, so no idea of how I could plug into that, or add wide-band O2...
Any resources you could steer me to read about engine management for the 3FE would be appreciated.

Signed, The Rookie-