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

[mudgudgeon]

Thanks @DancesWithMutts

I don't see any benefit to retaining any over-boost functionality. Mainly for the same reasons as using a large flat spot on the deep section of the taper - It sacrifices anreoid travel and therefore makes the useful taper shorter.

I had not thought about a progressive rate spring, It's a good Idea. I will have to see what the taper looks like in the end to see whether that would be beneficial or just a slightly stiffer spring.

I'm sure the Innovate MTX-L has some logging capabilities. I have not tried it to be honest. I would need a digital boost gauge with logging as well which I don't have.

I like the idea of marking the aneroid in increments. I think I will probably do something like this.

agreed. over-boost fuel cut function is there to prevent the OEM turbo from over-speeding and going POP


I also think a progressive spring rate, or two stage spring may have benefits. Problem is, its another variable that would take quite a bit of testing to get the spring rate right

 

[mudgudgeon]

I found this yesterday for the 1HD-T and didn't see it posted here. Thoughts?

I'm in the process of modifying the BACS altitude compensator on my 1HZ to be a boost compensator.
I an intending to optimise the tuneable functions of the boost compensator while it is apart, I have been making some measurements to figure out what are the useable limits of the boost compensator components/adjustments.

I'm looking at things like maximum useful grind depth on the aneroid pin, maximum possible travel of the aneroid.

From measurements I've done so far, the pin profile in red in the drawing above is largely useless.
The taper starts too far up the pin, this reduces the useable length of taper available. also, the aneroid pin cannot travel deep enough into the housing to use the full length of the suggested taper in red. the aneroid will bottom out before the follower pin gets to the full depth of the taper.
the taper is too deep. The follower pin, and the associated governor control lever inside the IP will run out of travel at approx 4-4.5mm depth. grinding the taper to 6mm is of no gain.

I've added some notes to the image from @vwluv10338 to try to clarify my comments. Id be interested to hear others thoughts, experiences with this.

@vwluv10388 , I'd be interested to know the source of the diagram you posted

Pin pictured above shows the standard taper for this pin finishes at approx 19mm from end of pin.
The taper could have started 6-7mm further down the pin, or ~2mm from the end.

 

[vwluv10338]

@mudgudgeon
I came across it on a 1HDT/1HZ Facebook group. Thanks for taking the time to analyze it

 

[mudgudgeon]

No worries.
I was looking back through old pages for something else and saw that diagram. It got me thinking some thing didn't add up.

 

[diby 2000]

That's awesome info @mudgudgeon

How deep is the taper on that pin?
It still could be usable of you start the ramp at 2mm from the end.

 

[diby 2000]

Especially if you end up with a concave ramp at the start.

 

[mudgudgeon]

@diby 2000 Yeah, you might be right.
I initially didn't like the look of it. Looks too short a taper, but based on my measurements, I might be able to do something with it. I don't like the groove around the base of it.
The current grind on it has a max depth of about 3.5mm

 

[diby 2000]

Yeah The grove will be what makes it useable or not.
I'm thinking the initial ramp will be slight with a concave fall after there is enough boost to effectively 'dump the fuel in '. I expect the concave cliff to be around 4 - 8 psi. But I have no real idea yet LOL.

 

[mudgudgeon]

yeah, i like the idea of possibly using a concave grind. Not sure how that would play out though.
need a reasonable $$ supply of pins to play with

I'm thinking I might set up the Zexel boost compensator on the bench and take some measurements of pin travel at different boost increments.

 

[diby 2000]

Just to clarify @mudgudgeon
Are your measurements purely for the Zexel compensater or are these measurements also the same for the Denso compensater?

 

[mudgudgeon]

Just to clarify @mudgudgeon
Are your measurements purely for the Zexel compensater or are these measurements also the same for the Denso compensater?

I have measured both, they are the same for both.
I will double check this arvo.

 

[diby 2000]

Cheers mate

 

[Antony]

The best aneroid pin's I've found if your not grinding are in zexel pumps fitted to Mitsubishi's 4m40 or Ford/Mazda's wl-t. The diameter is larger so there is more total travel but you would have to swap the aneroid bush too. That would be top cover off job.

 

[mudgudgeon]

The best aneroid pin's I've found if your not grinding are in zexel pumps fitted to Mitsubishi's 4m40 or Ford/Mazda's wl-t. The diameter is larger so there is more total travel but you would have to swap the aneroid bush too. That would be top cover off job.

Hey @Antony
how much larger diameter is the 4m40 Zexel pin?

 

[Antony]

@mudgudgeon I'll have a look tomorrow if I get a chance but I thought 1mm. I've used the wl-t more so than the 4m40 but they both allow for more stroke.

If I'm building something 'a lot above spec' I'll swap all the internals including the cover where the unboosted cam is as they have a screw directly on top of the aneroid pin making for easier adjustment. I'm not sure about oz but over here it's not hard to get hold of wl/4m pumps.

 

[mudgudgeon]

cheers Antony.

Just to clarify @mudgudgeon
Are your measurements purely for the Zexel compensater or are these measurements also the same for the Denso compensater?

so, the depth of the aneroid pin housing is the same, maybe 0.5mm deeper on the Denso top housing, but I think its just a slight variation in castings.
I cant get a good measurement on the amount of room for travel for the guide pin without removing the top over of the IP on my cruiser which I didn't really have time for today.

 

[diby 2000]

so, the depth of the aneroid pin housing is the same, maybe 0.5mm deeper on the Denso top housing, but I think its just a slight variation in castings.
I cant get a good measurement on the amount of room for travel for the guide pin without removing the top over of the IP on my cruiser which I didn't really have time for today.

No worries.
Thanks again.

 

[mudgudgeon]

Antony, if I understand this correctly, a 12mm vs 11 mm aneroid pin gives an extra 0.5mm possible travel for the guide pin, and therefore, also the stop lever. this puts the governor tension lever in a different resting or idle position?

the stop lever looks like its very close to a 1:1 leverage ratio, so the position of the governor tension lever is not going to change much at all. But the extra 0.5mm travel on the guide pin (or extra 0.5mm possible taper on the aneroid) is significant?

what does this mean for main fuel screw setting? Can you potentialy dial in a bit more fuel on the main fuel screw as the stop lever puts the governor tension lever at a position where its delivering less fuel at idle?

Sounds like you have a preference for a screw vs cam plate to adjust off idle position of the aneroid pin?

 

[mudgudgeon]

a couple of interesting videos. I thnik they have enough relevance and interest to put them here





How to time a VE Fuel Pump

 

[diby 2000]

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?