HD-FT pump tuning plan.

[hopeless wanderer]

Hi folks

Does anyone happen to have a HD-FT pump on the bench right now ? Or a HD-T if they are the same.
I was about to pull the trigger on a fancy new boost compensator cap which is taller to allow more movement of the fuel pin... Well then I found a spacer which will effectively perform the same function.
Then I discovered its 70 quid plus postage from "The land down under"
If someone could put the pump on a photocopier so I get the outline of the pump, the bolt holes and the recessed part where the diaphragm is seated, I'm going to get the spacer drawn up and 3D printed.
They'll be available for gratis (as in however much they cost to print ) or I'll just send or publish the file so you can have them 3d printed yourself. The picture I pinched from Chapel Gate shows the face I need to get a copy of and if you can give me the depth of the recessed part ill be cooking on gas.
Any advice, help or suggestions on spacer thickness would be most welcome.

 

[Towpack]

Why not take the existing top off and draw round it, mark the holes etc?
How does a spacer work anyhow. I thought turning the adjusting screw in increased the off boost fuelling?

 

[hopeless wanderer]

Why not take the existing top off and draw round it, mark the holes etc?
How does a spacer work anyhow. I thought turning the adjusting screw in increased the off boost fuelling?

As per usual I'm miles from my truck :-( ... I think about her every day though
I need the recess where the diaphragm sits, so it needs to be the bottom section.
I need the fuelling for the top end as my boost is up to the early 20s so bringing the pin up would get the follower up onto that unground part of the pin.
It gets starved at the top as the pin bottoms out, I've seen people on mud taking out shims that are in the bottom of the hole in order to get more top end fuel, I could grind further up the pin I suppose or even get a fancy pin but having seen the new cap or spacer both running at around 80 pounds once they arrive I figured I could 3D print. I won't lie I also want to see what this 3D printing malarkey is all about too.
I am not sure how it would work on stock turbos or if it'd be useful to cars with standard tune, That's where i'm hoping others will step in.

 

[Iwan]

It's a similar thing that I was thinking a while back. I looked at the Australian part number for the follower pin which I've read is slightly shorter (been a while since looking tho).

When I looked at the vertical pin on my euro egr motor ft it had the score mark starting quite late on the angle, which made me think that a portion of it was wasted before the score line starts.

So when I read your thinking HW you're thinking along the same lines, but I was thinking of shortening the horiz follower pin to raise the vertical one.

Be interested in your findings!

 

[Shayne]

 

[hopeless wanderer]

I am 100% not gonna do that to Brenda.

I have a cunning plan after talking to a guy in NZ (who wanted to sell me the fancy compensator cover)
I'm going to get an air/fuel ratio meter as I have a spare bung in the exhaust for an EGT that I didn't use.
I'm going to hook that up and detach and blank the boost line to the pump but still keep the line to the boost gauge.
With the compensator off I'm going to put different diameter drill bits into the hole the fuel pin sits in and take readings at 1000/2000/3000/4000 rpm till I get the perfect air/fuel ratio for each. ( I may do it in 500rpm increments) That will give me the amount of metal I need to take off the pin at each point in the rev range.
I'll also record how much boost is being generated at these points and then like the guy in the first video ill mark the blank pin corresponding to each reading and machine the pin accordingly. I'll just use a lathe as the fuelling will be perfect for my engine it can be symmetrical.

 

[hopeless wanderer]

I know from someone posting a pic on mud that the standard pin has 17mm of travel before it bottoms out in the housing. If I bring the pin up that increases the range I have to tune with. if I get the theoretical 22mm of pin travel I can machine in say 5mm steps to suit my rev range, leaving 2mm unground at the bottom for off boost/idle fuel
If I can take the shims out of the bottom of the hole that 22mm of travel may increase further ?
Obviously the main fuel screw set the limit for max fuel so I might take it up to 4000rpm, set the main fuel screw for the perfect ratio at that engine speed and then work backwards and do the steps I mentioned above.
Then comes the tricky part ... finding a spring setting that lets the pin travel freely across its full range, I know some tuners take out the star wheel and use shims to achieve that. The point is to have a spring that's not so slack so that it reacts quickly but goes into over fuelling too early.
Sorry about the long messages but I'm thinking out loud. All advice would be welcomed and greatly appreciated.

 

[Shayne]

I am 100% not gonna do that to Brenda.

Wanna do two pins and send one to me

 

[hopeless wanderer]

Wanna do two pins and send one to me

Soon as I've got my blank pin machined I'll post drawings. I've learnt so much on this forum I've gotta play it forward.