Does the STANDARD aneroid pin allow full fuel at full boost (thinnest part of taper)? Or is it still restricting it in comparison to the main set screw setting?
As such, does rotating the aneroid pin affect any change at FULL boost when the pin is fully depressed?
I am only talking full boost and not confusing any low boost aspect of the pin.
I think the narrowest section on a stock pin is offset. The tapered grind is offset, so I'm fairly sure the thinnest but is not centred.
It still depends on how the boost compensator is set up. At full boost, the Android pin can be pushed deep enough that the following pin is back on the taper above the thinnest but and is cutting fuel flow
As mud said the pin is eccentric at the thinnest part. So if the pin travel is set correctly the longest ramp will give the most fuel but slowest spool and the shortest ramp will give the least fuel but the quckest spool.
The short ramp is steep and the long ramp is shallow.
I believe the follower pin still has travel left at the thinnest part so you can grind deeper to release more fuel.
Yes, probably correct, but you would lose a lot of your ability to fine tune fuel delivery.
To get max fuel available at WOT, you'll have a very Smokey idle and high EGTs at high load low rpm.
What are you trying to achieve?
The stock 1HD-T pump is reported to be good for 200hp
You can't remove it completely as there is another pin that tracks against the ramp. If that is pushed completely in it will expose an o-ring and you'll have a large leak.
The boost compensator is essentially made up of 3 moving part. The pin with the ramp, another pin and lever. It does restrict fuel at unboosted conditions then releases the fulcrum inside the pump (set via the full load screw) as it boosts and increases fuel. The total travel of the ramp sets the difference between unboosted and boosted fuel eg at standard you may have 40cc unboosted and 70cc boosted. Turn it 180* and you may have 40cc & 75cc due to the pin being eccentric. Put a custom grind on it and increase travel and you could have 40cc & 100cc but at some point you are going to want to adjust the full load screw to move your base line.
Really to answer your question take your hose off your boost compensator, block it and then turn your fuel screw in. Thats achieving the same result.
No need to remove - was just an illustration of the scenario.
I am nowhere near max power. I am just trying to confirm the pin's effect on fueling at full boost.
I was always under the understanding that the stock pin changed the ramp but the max fuel was still governed by the fuel screw. This is not totally correct as by the above you can add or subtract fuel at full boost by rotating the pin.
Depending on your starting point, the pin rotation can add or subtract fuel under no boost also.
Ok, well if you were to remove the pin, look at the ramp and rotated 360* it you can see that its eccentric. Some are less so in the area of no boost so have less effect on no boost than boosted fuel. Some pins the area under full boost it ins't eccentric at all and the only eccentric part is in the area of mid boost/no boost. In those case the full load screw is the only way to increase fuel.
For example if I was setting up a pump on the test bench. First I would set a) full load under full boost on its screw say 80cc. Then b) drop boost to zero and set it to 45cc on the top screw. Then c) check a midway boost point for 60cc. If for any reason b or c couldn't be achieved I would either be shimming for total travel or rotating the pin. Full load is the maximum fuel the engine would see under full load conditions and would always be set on that screw on the test bench.
Cheers. What I have is a fairly newly built pump that I am unhappy with the aneroid settings. Forget the shop doing it again, so I am trying to resolve:
Sluggish off Mark
Slow to spool
Ok at full boost verging on too rich.
Current settings:
No boost cam adjustment is already set at maximum.
Star wheel probably too much tension.
Eccentric pin appears to be almost at its maximum fueling profile.
The 12 valves were always abit sluggish off the mark. I reset the star wheel to its lightest position, all in by 5 psi and set the unboosted 8-12cc above spec on all my rebuilds (this is on standard 1hd-t setups). In your situation if its verging on black smoke at full boost and the no boost setting is at max your best option is to lessen the tension on the star wheel. Another option is to pull apart the unboosted screw and cam and put a copper washer in between it to space it down. This is a less than ideal fix but it will give you more unboosted fuel to help it off the mark.
Note the lightest position isn't necessarily the whole way down as you can get to the point where the spring is no longer bound but you can feel how much tension is on the spring when you refit the cover.
Aneroid pin half way between long and short ramp. smoke adjustment screw on the thinnest part and the star wheel with minimum preload. As Anthony said when you replace the cover you barely feel the spring tension. Next is working out your full load screw.
Do you agree Anthony.
Do you have EGT or AFR guages and a boost gauge?
P.S I have no training in this, only self taught so im happy to be schooled myself.
Cheers Mud I have read that a few times and also all the other links on the web. Perhaps not since the latest a threads though. Have also studied FSM.
Yes - have boost, AFR and EGT gauges. Have been monitoring all.
Is it true that if I hold the throttle lever open and push the follower pin back across that the aneroid pin will slip in without grinding a chamfer off it?
A bloke at a pump shop told me this.
My truck is very slow to spool up to 5psi. Better after this so I assume way too much tension.
It is smoke free with AFRs above 21:1 in that no boost to low boost zone.
I have been running around in circles since I was told that AFRs should be steady through rev range and confused how if the cam for no boost is at maximum that it is still so slow off the mark.
Sounds the the biggest offender is the spring.
Should I be aiming to have the follower pin just reach the flat section of the aneroid pin at full boost (11) or can it reach this a little lower around 9 or 10?
Yes more or less, draw a line on the top on the diaphragm as a point of reference and work in 1/8 or 1/4 turns. Turn your smoke adjustment to the thickest part for maximum unboost fuel or thinnest for less unboosted and work from there. I'd only turn your full load screw in 1/8 turns if you start playing with it. Using an EGT gauge definitely makes life easier.
Leave the throttle at idle and you can push the follower pin in and aneroid pin will drop straight in. Back the star wheel right back until you can only just feel tension on the cover. This will have the follower pin reaching the flat section about 5-6 psi and actually starting to move 0-1 psi. I'm generally more interested in getting the aneroid pin moving as soon as possible under boost than how long it takes to get to full boost unless I'm building a high boost application. For example if you set the follower pin to reach the flat by 10 psi the aneroid pin might not start moving until 2-3 psi which can give you some lag.
