The Official 1HD-T/FT Fuel Pump Mod Tuning Thread (1 Viewer)
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yotahed
Diesel Head
You're welcome to believe that. But its certainly not correct. Even redneck Cummins tuners know that.
The spring preload has nothing to do with the initial position of the pin. It is forced to the top cover against the adjusting screw. Commonly referred to as the smoke screw, why? Because it makes smoke when OFF BOOST. Because you are manually adjusting the pin depth and therefore moving the full load stop link in and up the ramp. The spring preload is what is adjusted when you want more or less travel of the pin at a given boost level.
I too, build pumps everyday in a licensed shop. The bench doesn't lie. And neither do pleased customers.
The spring preload has nothing to do with the initial position of the pin. It is forced to the top cover against the adjusting screw. Commonly referred to as the smoke screw, why? Because it makes smoke when OFF BOOST. Because you are manually adjusting the pin depth and therefore moving the full load stop link in and up the ramp. The spring preload is what is adjusted when you want more or less travel of the pin at a given boost level.
I too, build pumps everyday in a licensed shop. The bench doesn't lie. And neither do pleased customers.
That is completely related to the angle of the push rod taper used and the start position. In reality, the fuel screw position is what controls preboost. Turning the cam plate to adjust the push rod to a deeper start position is also adding preload to the spring (although the maximum depth of the pushrod vs psi doesn't change). First thing we do is get rid of all of that. 99% of pumps I tune have the star wheel jammed to the alloy housing, and fuel screw maxed.
So if I grind the cam plate flat to about 3mm and replace the two thick diaphragm washers with two really thin ones (i still want to support the diaphragm) I'll be starting off boost at minimum fuel. Then I grind my custom pin to meet my preferred fuel/boost curve, lower my spring tension so it can come in nice and quick, wind the max rpm governor screw right off so I can get WOT, check my pedal/cable for the same. When I get it right where I want it, screw my total fuel in a bit more until my EGT hits 650'C peak pre turbo. Am I on the right track? Is this my 10mm VE at max?
I have just sent my 10mm pin to a mate who has a first class machining company here in Perth to make me some blank pins. Would anyone else be interested in 10mm, 11mm, 12mm blank pins?
Out of the goodness of my heart to all Mudders
No middleman, if he can make it cheap enough to sell heaps, I'll release his number to everyone and you can go direct. If that happens he will need someone to lend him an 11mm & 12mm pin as templates, which you'll get straight back.
Out of the goodness of my heart to all Mudders
No middleman, if he can make it cheap enough to sell heaps, I'll release his number to everyone and you can go direct. If that happens he will need someone to lend him an 11mm & 12mm pin as templates, which you'll get straight back.
yotahed
Diesel Head
Interesting tuning concept.
Whatever. You can flap about how you tune and how you're right. lts really up to the end user to decide how they want to do it.
I've seen your pin grinds, can't say I was impressed.
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I think he means when they come to him for tuning. Not taking sides, but yeah, even I can see that soft spring / max fuel side is clumsy / max
Taking the cam back to flat and out of the equation allows you to focus on the pin grind for where the fuel comes in and how much, then the spring tension for how fast it comes in.
Does anyone play around with/modify the follower pin length?
Taking the cam back to flat and out of the equation allows you to focus on the pin grind for where the fuel comes in and how much, then the spring tension for how fast it comes in.
Does anyone play around with/modify the follower pin length?
I have no idea what the thought was behind that. The pumps are still Denso pumps, and pretty much all the parts are interchangeable with the truck pumps (so my pump guy tells me). I had the pump calibrated to the specs that Graeme gave me with his turbo, and it all runs fantastic. I do not remotely have the knowledge or expertise of the guys above...
yotahed
Diesel Head
You're thinking is correct. You'll just have to play with the preload to get the response just right. Just be careful with the max RpM governor/throttle screw. You don't want it revving too high.
yotahed
Diesel Head
I never said how I tune pumps, up to this point I ve only had to test one. And that was your pump. I told the guy who bought it from you that he should change the pin because it was a half-assed grind and looked like it was done by a 5 year old playing with a grinder.
I'm very well aware of DENSO pumps limited aneroid adjustability. Try working on a Volkswagen pump. Then you'll know what limited adjustment is.
The person who originally asked the question probably has a STOCK pump. So you're advice to him is useless. 1HDT pins ride about the middle of the ramp so there is plenty of off -boost adjustment.
Your pin rides from the very bottom to the very top, so yes, in YOUR pump you'd have to adjust differently.
I'm very well aware of DENSO pumps limited aneroid adjustability. Try working on a Volkswagen pump. Then you'll know what limited adjustment is.
The person who originally asked the question probably has a STOCK pump. So you're advice to him is useless. 1HDT pins ride about the middle of the ramp so there is plenty of off -boost adjustment.
Your pin rides from the very bottom to the very top, so yes, in YOUR pump you'd have to adjust differently.
Stock 1hdt/FT's benefit greatly from a good tune (even at stock boost levels). Lively, responsive, knocks 4 seconds off 0-100kph. Totally different driving experience. I tune pre boost, highway and max load/max boost. Playing with the cam plate and fuel screw is what EVERY dyno/ tuning place does. And totally useless. I've had plenty of people come straight from getting a tune elsewhere that they aren't happy with.
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yotahed
Diesel Head
So you don't even know what's in pumps that you sell people? Interesting.
As far as a good tune goes, no s***.
As far as a good tune goes, no s***.
Come on you two play nice, we're all in this together. That's the whole point of IH8MUD, sharing, learning and helping each other out.
yotahed
Diesel Head
Sorry guys
I feel very lucky to have access to so many professional, experienced people that are willing to share their knowledge freely. Beers all round on me if we're ever in close proximity.
Here's a question that goes with my previous one about follower pins:
Has anyone played around with different, double or tapered springs? I'm wondering if you can set up a multi stage tension to match the different stages of your pin.
Everyone is on to star wheels, pin grinds, shims and washers, but what else is there I wonder?
Has anyone played around with different, double or tapered springs? I'm wondering if you can set up a multi stage tension to match the different stages of your pin.
Everyone is on to star wheels, pin grinds, shims and washers, but what else is there I wonder?
Hey now this is different. I've never seen injection pump tuners argue. We can learn a lot from this. Keep it up guys!
Look at you all high and mighty. Come and tune these things day in/day out. Then try and tell me something. I couldn't give a f$&k if your impressed or not. No! That's not the push rod that's supposed to be in there. I don't tune any pins, unless its on the truck - custom tune. Let alone send out any modified ones and say it will work. I send out stock pins or blanks at the owners request.
