The Official 1HD-T/FT Fuel Pump Mod Tuning Thread (7 Viewers)

[mudgudgeon]

Cool. Diaphragm sits on top side of this, yeah?

I think this is a good idea. Lots of pics of aneroid pins show the wear mark starting fairly high on the pin. Lifting the pin higher in the housing would put it in a better starting position, retain full adjustability and make the full range of pin travel available for tuning.

How thick is your spacer?

 

[diby 2000]

I have the spacer above the diaphragm but it won't matter where it sits really. It's only to raise the smoke screw cam higher from the pump housing.

This spacer is about 2mm. If I remeber I will measure it tonight. I'm thinking of making another one as well, but sure if I'll need it yet. It's only thick gasket material.

 

[vwluv10338]

I can't remember Graemes proceedure of the top of my head but I assume he would be grinding the ovetboost section of the aneroid away so it can't ride up into it.
This respectively gives more room for the ramp and removes the ovetboost section at the same time.
I plan on doing the same soon.

Edit.
Sorry, delayed response.
After reading that he does not grind the ovetboost section, only makes the full boost section deeper to allow a larger differential from no boost to full boost fuel.
The aneroid travel seems to be only limited by the spring preload, adjusted via the star wheel.

My thought was to throw a pin in my lathe and turn it up to significantly increase the length of the full boost section and raise the fuel cut. I'm not sure how much better that is or if having the increased spring tension would be better.

My thoughts on aggressive vs less aggressive taper on the standard pins has changed.
To me, the taper is the same all around, the difference is the depth of the grind is offset.

In the pic above, if you rotate the aneroid pin so the guide pin is following the left side, you're starting from a base of higher fueling.
Ramp rate is the same.

If you change nothing else, but rotate the aneroid pin, you'll increase/reduce fuel because the guide pin is again a deeper, or shallower grind.
The cam/off idle fuel screw on top fine tunes this. It either pushes the aneroid deeper (more fuel) or lifts it (less fuel).
If you start with the off idle fuel screw with the thinnest part in contact with the aneroid pin (aneroid at highest position) 180° turn takes you from min to max (aneroid deeper), direction of rotation doesn't matter. Interesting that gturbo states this is redundant. It allows a bit of easily accessible fine tuning of the aneroid position without lifting the top cover off

I like the gturbo suggestion of setting the aneroid pin depth so at rest, the follower pin is on the full diameter of the aneroid.

I tend to agree that it may be the same taper but because it's not in the center of the pin the length of the ramp changes.

The 11 herbs and spices!
I think that's the first time I've seen this posted.

Is it complete?
Some good info there, but it leaves a few questions I think.

I have all of it but this is the tuning part. The earlier pages just explain what each part does. I got it from here so someone posted it on the forum but I don't remember where.

Here's a pic of the star wheel, and the aneroid pin bushing.
The wheel has maybe 60 notches around it (rough estimate).
The thread pitch is quite fine too. Maybe 1.25mm or (again, an estimate) may be 1.5mm.
View attachment 1483418

If you're making big adjustments, it's far easier to take the aneroid cover off, remove the aneroid and diaphragm and rotate the star wheel from the top. If you remove the aneroid pin, you'll need to grind the bottom edge to get it back in if it hasn't already been ground.

That was how I was adjusting it because each time I was painting it to check the tension for fuel cut

 

[diby 2000]

My thought was to throw a pin in my lathe and turn it up to significantly increase the length of the full boost section and raise the fuel cut. I'm not sure how much better that is or if having the increased spring tension would be better.

It's hard to know which way will be better for for 20psi but I would be tempted to just increase the spring preload for now and see how that works for you.
Or make a spacer washer to stop the pin from reaching the ovetboost section. That's what I'm doing right now.

 

[vwluv10338]

It's hard to know which way will be better for for 20psi but I would be tempted to just increase the spring preload for now and see how that works for you.
Or make a spacer washer to stop the pin from reaching the ovetboost section. That's what I'm doing right now.

Yeah I'm just thinking. I'm not grinding anything till at least all my mods are done anyway. I had thought of milling up some blanks as well but I don't really have the time and I need to get better at threading. Your spacer looks like the guy I tagged from 20 pages back that bought a metal spacer with an o ring and new spring with shims. He never responded to how that was working out for him. I wonder where he picked it up.

 

[diby 2000]

Yeah I'm just thinking. I'm not grinding anything till at least all my mods are done anyway. I had thought of milling up some blanks as well but I don't really have the time and I need to get better at threading. Your spacer looks like the guy I tagged from 20 pages back that bought a metal spacer with an o ring and new spring with shims. He never responded to how that was working out for him. I wonder where he picked it up.

Yeah I had this exact idea in mind when he posted those pics.
I think he said he got them room from ADS Injection - a diesel injection workshop in Cairns.
I was also wondering if a new, higher spring rate spring would be beneficial for higher boost or not.
Time will tell.

 

[mudgudgeon]

I had thought of milling up some blanks

They need to be case hardened and polished to prevent excessive wear.

 

[vwluv10338]

They need to be case hardened and polished to prevent excessive wear.

Easy enough. I have used heat and quenching to harden metal before

 

[diby 2000]

How thick is your spacer?

Just measured it at 1.5mm
With this spacer and the no boost cam at its smallest profile the follower pin in JUST off the outer aneroid diameter. So close you cant see the difference unless you look REALLY close.
A 2mm spacer would be perfect.

 

[mudgudgeon]

Easy enough. I have used heat and quenching to harden metal before

well then, you might have a customer here if you get around to it

 

[vwluv10338]

I found an interesting thread where the Cummins guys were discussing using a bleeder in the line to their AFC to avoid fuel cut and have more tune ability. Something like in this diagram. I believe they were bleeding off some pressure which I could see slowing down response but then I thought of what if you added a manual boost controller on the tee? If it was set to the factory 10 psi then you could have the spring tension set so the pin began moving at 1 psi but at soon as the turbo hits 10 psi it bleeds off pressure to the diaphragm to keep it out of fuel cut. Acting like a wastegate of sorts. Just kicking around ideas.

 

[vwluv10338]

well then, you might have a customer here if you get around to it

I would think the best way would be to grind them and then harden them once the cut was put on them. Someone in this thread 20 pages back had someone make blanks and posted a pic of them

 

[diby 2000]

I found an interesting thread where the Cummins guys were discussing using a bleeder in the line to their AFC to avoid fuel cut and have more tune ability. Something like in this diagram. I believe they were bleeding off some pressure which I could see slowing down response but then I thought of what if you added a manual boost controller on the tee? If it was set to the factory 10 psi then you could have the spring tension set so the pin began moving at 1 psi but at soon as the turbo hits 10 psi it bleeds off pressure to the diaphragm to keep it out of fuel cut. Acting like a wastegate of sorts. Just kicking around ideas.

I think the bleed valve in the pic is like a needle valve manual boost controller.
The issues is that these are not pressure relief valves though I guess something like that may acheive what your after.
I see this setup functioning just the same as a stiffer spring, though more easily tuned but with extra components and complication.
I may think about trialing this down the line. Thanks for the info.

I would think the best way would be to grind them and then harden them once the cut was put on them.

I think this would be the best way to go though you would need to know what your grind looked like first. Catch 22?

 

[vwluv10338]

The way I initially read it, and I could be wrong, was that they were bleeding pressure off in a more linear fashion. My thought was to have it act more like a wastegate so that as soon as some pressure is built the pin starts to move and it moves like stock but once it gets to 10 psi the manual boost controller bleeds off the extra pressure so it doesn't go into fuel cut. With adding pretension to the spring it's going to take more turbo pressure to get the rod moving. It seems like with the spring pressure you can only make one adjustment when you need two, the psi where it moves and keeping it out of fuel cut. Then again maybe it just needs a longer ramp.

As far as the blanks I would think having them raw you could grind them till you were happy with them and then heat them up to harden once you were happy with it

I think the bleed valve in the pic is like a needle valve manual boost controller.
The issues is that these are not pressure relief valves though I guess something like that may acheive what your after.
I see this setup functioning just the same as a stiffer spring, though more easily tuned but with extra components and complication.
I may think about trialing this down the line. Thanks for the info.

I think this would be the best way to go though you would need to know what your grind looked like first. Catch 22?

 

[vwluv10338]

Thinking more how about a pressure regulator? Set it to the 10 psi of stock. As it built boost it would see 0-10psi then it would never see more than that

http://www.piecoweb.com/us/airtac-gr200-regulator-1-8-npt?gclid=CLi6kqSa1NQCFZCPswodLywClw

 

[vwluv10338]

More interesting things I found
AFC Live (Patent Pending) Mechanical Tuner Kit | Power Driven Diesel

 

[IanB]

I must not be getting my head around this, you're looking to trick the boost compensator into seeing only 10psi, while you plan on running more like 24psi (more than 10psi is all that matters here)? So you'll see full fueling with respect to the boost compensator from 10psi and up? Why is this desirable? What am I missing? This seems like it would lose all tuning resolution in the 11-?psi range of operation.

 

[vwluv10338]

I must not be getting my head around this, you're looking to trick the boost compensator into seeing only 10psi, while you plan on running more like 24psi (more than 10psi is all that matters here)? So you'll see full fueling with respect to the boost compensator from 10psi and up? Why is this desirable? What am I missing? This seems like it would lose all tuning resolution in the 11-?psi range of operation.

I wasn't really planning anything as this was something I came across the first gen Cummins guys discussing. Then again they sometimes also remove the boost compensator so I'm not sure how to take that.
My thoughts are that as you increase spring tension it takes more boost to overcome the spring and get the pin moving. I would think I would want the pin to start moving earlier as it was stock. Similar to Graeme's tuning guide where he wants the pin to move at 1-3psi. If I add tension isn't that going to cause the pin to move later and therefore not increase fuel till more boost is built? I guess my issue is that I'm not understanding how adding a bunch more spring tension isn't going to negatively affect the down low performance. Then again as I type that I guess that can be overcome with a deeper grind on the pin.

 

[GTSSportCoupe]

Some of us with 2LTE (electronic diesel) have been doing the bleed off trick to the boost sensor. It works very well for the electronic injection systems, but I don't see how it would really gain anything for the mechanical injection system (boost comp).

The reason we do it on the electronic engine, is to keep the computer from going into fuel cut. This happens around 14 psi on that motor. I run about 19psi. I use a special bleed valve that bleeds boost in a linear fashion, NOT a clamping fashion. So the computer will see 0-14psi, when the pressure in the intake manifold is actually 0-19psi. I use a fuel adjustment on the electronic pump to tune the fueling to suit the extra air.

Here is a thread on mud on how to do this. I copied his setup basically. Reducing 2lte egt's

 

[IanB]

Off-boost performance is controlled by the "smoke screw" cam adjustment on the boost compensator lid, and once boost starts building it builds quickly. You could use shims to alter the starting depth of the pin in the compensator body if need be.

I'm working in theory as I've not yet dug into my pump tuning, but I think having some tuning resolution would be more important in the 10-25psi range than in the 0-10psi range due to variance of air volume and the fuel requirements that would follow. I guess I've got to get to playing with it to gain some context.

I can totally understand why you'd do this on an electronically controlled injection pump, but why introduce limitations like this on a mechanical one?

That AFC Live setup looks amazing, @Wheelingnoob has one on his Cummins swap and had good things to say about it. I wonder if it could be adapted to our pumps?