The Official 1HD-T/FT Fuel Pump Mod Tuning Thread (13 Viewers)

[mudgudgeon]

Another thought.
Is the limiting factor for the stop leaver and therefore the follower pin, the length of the follower pin itself or is it the free space in the housing for the lever to move?

I think I understand what you are asking @mudgudgeon and while I think you are correct, I would think about it the other way around. The main advantage to a larger diameter aneroid, translating to more follower pin travel would be an increased differentiation between no boost and full boost fueling.
I could have it wrong, please direct me if I do, but I don't think this can make the pump deliver more fuel than what it would otherwise deliver would it?

limiting factor is free space in the housing, the lever will bottom out aginst the housing. you could possibly clearance the housing for a little more travel. it seems even 0.5mm is significant here, so a little clearancing might be worth while. there is a screwed in steel bushing for the guide pin though.

yeah, we are thinking the same way, just describing the result differently.
the greater difference between no boost fuel and full boost fuel is what we are talking about. I think having a larger diameter aneroid puts you at a lower starting point on the no boost fuel setting, potentially leaving more room for fuel up top.
EGTs or AFR is probably going to be the limiter on full boost fuel

 

[mudgudgeon]

this drawing more or less shows the stop lever contacting the guide pin bush with the guide pin in max fuel position.

bit of a lame grind on that aneroid pin

 

[diby 2000]

limiting factor is free space in the housing, the lever will bottom out aginst the housing. you could possibly clearance the housing for a little more travel. it seems even 0.5mm is significant here, so a little clearancing might be worth while. there is a screwed in steel bushing for the guide pin though.

yeah, we are thinking the same way, just describing the result differently.
the greater difference between no boost fuel and full boost fuel is what we are talking about. I think having a larger diameter aneroid puts you at a lower starting point on the no boost fuel setting, potentially leaving more room for fuel up top.
EGTs or AFR is probably going to be the limiter on full boost fuel

Agreed. If full pin travel is only 4mm, another 0.5mm is another 12.5% travel. This could be the difference between a black cloud of soot and a dark haze at no boost full boot.

View attachment 1448629

this drawing more or less shows the stop lever contacting the guide pin bush with the guide pin in max fuel position.

bit of a lame grind on that aneroid pin

That's a good pic. Lame grind is a bit of an understatement lol.
So to clearance even the guide pin push the whole lot would need to come off.
Hmm might be a bit deep for me at this stage.

 

[Antony]

@mudgudgeon yes you will gain an extra 0.5-1.0mm travel and does make life alot easier when your trying to get more of a difference between unboosted & boosted fuel. I havn't measured the stop lever before but it could be 1 to 1. The adjusting lever, tensioning lever and start lever are part of an assembly (fulcrum lever) that sits in the control sleeve. Moving the full load screw a meaningful amount will effect idle and start fuel as you are moving the adjusting lever which changes the control sleeves static position but not alot. The tesioning lever and start lever are attach and can move independent of the adjusting lever and move the spill sleeve dynamically.

You can see above the control sleeve. When you move the throttle lever to its high idle/max rpm, it loads the governor springs forcing the flyweights down and moving the control sleeve right. That increases effective stroke thus injecting more fuel. If you have a boost compensator fitted the control sleeve wont be complete right until max boost is achieved. It this point if the fulcrum lever doesnt have torque control the control sleeve wont move left until the flyweights centrifugal force over comes the governor spring force. That will either happen at max rpm or if you lift your foot reducing spring force.

 

[Antony]

And this is the pin and cover off a zexel wl-t

Zexel left Denso right

Grinding is the easiest option. I just prefer to use this setup as I can trust its reliability and always achieve the result I'm after.

 

[mudgudgeon]

thanks @Antony for taking the time for that explanation. there's a lot going on in these pumps, and so much is interdependent!

does the groove on the pin serve any purpose?

I was thinking about this at work today (don't tell my new boss ), any reading i've done on powering up Dodge Cummins with the VE pump, the pins seem to often have a convex grind, and not an eccentric cone shape, and often starting from the very bottom of the pin, leaving just enough full diameter for the guide pin to touch on.

Any thoughts on this vs eccentric cone? I think rotating the pin away from the centre line is still going to alter the taper profile.

the second pin has a sharp increase initially which would help spool up, then mellows out, before increasing the ramp rate toward full boost

 

[Antony]

@mudgudgeon Im not aware of that to groove have a specific purpose.

The main advantage of that convex grind is total travel, a bigger spread between boosted and unboosted. I'm guessing they are custom but I've seen them (made by Bosch) in high boost marine applications. And of course the odd pump turns up which someones taken to it with a die grinder

All the manufacturers seem to design there systems with limitations on purpose to stop easy modifications. 95% of my work has me repairing everything within their specifications but by far the more interesting stuff is modifying stuff out of spec.

 

[Antony]

You have to remember that profile only effects it only at wide open throttle. It gives you a fuel rate as boost increases as you would know. I'm not sure if its been developed with proven results or someone designed it just thinking it was a good idea. The design of these pumps while being complex are also quite simple and crude. A long way behind the electronic stuff that followed.

 

[mudgudgeon]

yep both pins are aftermarket performance pins for cummins. seems to be a popular profile among different aftermarket suppliers

 

[mudgudgeon]

You have to remember that profile only effects it only at wide open throttle. It gives you a fuel rate as boost increases as you would know. I'm not sure if its been developed with proven results or someone designed it just thinking it was a good idea. The design of these pumps while being complex are also quite simple and crude. A long way behind the electronic stuff that followed.

the aneroid pin will move at part throttle too though? I guess at part throttle, fuel delivery is controlled by your right foot, so aneroid position is not really significant at part throttle

 

[Antony]

Is anyone making ones like that for 1HD-T's? Sometime last year I tested a pump from an Ozzy company (had a skull logo) that had something similar in it. Wasn't overly impressive with the quality of the build but the cruiser did preform well.

 

[Antony]

the aneroid pin will move at part throttle too though? I guess at part throttle, fuel delivery is controlled by your right foot, so aneroid position is not really significant at part throttle

The throttle is connected directly to the fulcrum lever via a spring or spring assembly. The boost compensator holds the fulcrum lever back so your thoughts at part throttle are correct. The boost compensator will work regardless of throttle position but only effect fuel when in contact with the fulcrum lever.

 

[mudgudgeon]

Is anyone making ones like that for 1HD-T's? Sometime last year I tested a pump from an Ozzy company (had a skull logo) that had something similar in it. Wasn't overly impressive with the quality of the build but the cruiser did preform well.

i haven't seen a source of aftermarket pins for 1hd-t like that. i've seen several similar variations for dodge cummins. I'm not sure if the cummins VE has the same diameter pin though

 

[Antony]

Cummins will be Bosch so bigger from memory, I'd imagine they are the same size as the larger Zexel design.

 

[VK3FHDJ]

To go back a page or 2. That pin grind picture was something i put together conceptually with my car and pin 4000+km away.... had to keep the brain ticking over at work so its definitely not based on any measurements and I was only trying to visualize what I was trying to acheive through reading the GTurbo tuning instructions.

 

[mudgudgeon]

To go back a page or 2. That pin grind picture was something i put together conceptually with my car and pin 4000+km away.... had to keep the brain ticking over at work so its definitely not based on any measurements and I was only trying to visualize what I was trying to acheive through reading the GTurbo tuning instructions.

Conceptually, I think you almost nailed it
It was certainly helpful as something to get the thinking process ticking over, and to get some measurements nailed down

 

[AussieHJCruza]

From memory, the XXi pump I had on my old 80 had a concave grind on the pin.

 

[loucaojr]

A few pages back a fellow mudder was mentioning the differences in the IP and injectors of the Yanmar vs the Toyota version.
That was clear... But what's the effect of running higher injector pop pressure with the same pump? If my question makes any sense..

Cheers

 

[franklin40]

i've been reading this thread off and on for quite a while and am just getting into tuning up my engine. i tried playing with the off boost adjustment and the aneroid pin rotation. i also put in a boost controller and have it set to 12 psi for starters. i have rotated the android pin 1/4 turn first and then another 1/4 turn assuming that it was originally in the stock location. i didn't notice any extra smoke extra power or extra egt's. what am i missing? i thought i should have been able to feel some difference in my butt dyno but no joy!! i haven't played with the clicker wheel (don't know the proper term). i haven't pulled the android out yet either as i haven't ground it and didn't want to get into that yet. i'm getting injectors rebuild next week and pump looked at to see if it needs a refresh. after that ill to a more i depth tune. i just thought i'd play a little but didn't notice any difference. air filter just cleaned. i have the ct-26 turbo but it's had a super flow wheel installed and ceramic coated so it's not a stock turbo. otherwise no other engine mods.

 

[Lumpskie]

@franklin40 I'd start with modifying your aneroid and taking a look at your boost compensator. IMO, 12psi is pretty low... you can probably bump up to 14psi to start. Then you can adjust the clicker (star) wheel to match you increased boost. The combination of boost and fueling matching each other will make a big difference. Once you get those set. Then look at rotating the aneroid for more fuel. My guess is that, right now, you are bottoming out your aneroid on the shoulder of the pin with your boost.