DB2 Tuning Guide

Kevo1288

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Hmm that really sucks. As I just went through installing one. Maybe I'll just leave the truck at intake and exhaust for now. :fan:
 

Macrobb

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Related question:
Anyone know much about shimming the governor spring? I've heard that it's a viable option for higher RPM defuel vs using a 6.2/6.5 spring. What I need to know is what's the ID, OD and thickness of the shim supposed to be. I'll see if I can just make one at work and try it out.
 

Thewespaul

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Related question:
Anyone know much about shimming the governor spring? I've heard that it's a viable option for higher RPM defuel vs using a 6.2/6.5 spring. What I need to know is what's the ID, OD and thickness of the shim supposed to be. I'll see if I can just make one at work and try it out.
I’ve seen it done on the old American Bosch pumps, but with the db2s I will usually stretch the spring a half inch to an inch over its original length for a modest increase in rpms, or put in the 6.2 spring in for 4500 rpm defuel.
 

jetfly12

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I did most of these steps and I can say I am very pleased. So far in the tuning, I have punched out the pressure relieve valve, backed out the torque screw all the way, and bottomed out the "minimax" and boy did it wake the motor up! I do have Stage 1 injectors so my throttle response is much better/more sensitive. And my stage 1 drop in turbo spools sooner/quicker. I think my rpms are higher now as I can get a little more mph out of each gear on my zf5 but my rpm gauge is not accurate, prolly just need a new tach sensor. However, I have noticed timing is a little louder/chattier on the bottom half of the rpm curve while cruising, so I may have to back off the timing or adjust the cam plate. Also wanted to follow up on the electric fuel pump, I just have a facet 40222 with no regulator, seems to be doing just fine and no filter light yet, so no pressure vacuum pre IP.

The only thing I did not touch is the fuel screw and I know I have 2-3 flats left from max because I backed it off last time I adjusted it. I know the fuel screw greatly effects top end fueling and egt's. Right now I have my wastegate shut and hovers around 15-16psi and 800 egts going up hills so I got plently of egts to spare. I do not have headstuds, so I am comfortable staying at 15psi. I haven't decided if I will experiment the maxed out fuel screw and take it out for a test drive or wait until I get my ford 6.0 intercooler installed and hooked up, see what the pressure drop is and adjust/tune accordingly.
Thanks again for sharing the guide!
 

Thewespaul

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I did most of these steps and I can say I am very pleased. So far in the tuning, I have punched out the pressure relieve valve, backed out the torque screw all the way, and bottomed out the "minimax" and boy did it wake the motor up! I do have Stage 1 injectors so my throttle response is much better/more sensitive. And my stage 1 drop in turbo spools sooner/quicker. I think my rpms are higher now as I can get a little more mph out of each gear on my zf5 but my rpm gauge is not accurate, prolly just need a new tach sensor. However, I have noticed timing is a little louder/chattier on the bottom half of the rpm curve while cruising, so I may have to back off the timing or adjust the cam plate. Also wanted to follow up on the electric fuel pump, I just have a facet 40222 with no regulator, seems to be doing just fine and no filter light yet, so no pressure vacuum pre IP.

The only thing I did not touch is the fuel screw and I know I have 2-3 flats left from max because I backed it off last time I adjusted it. I know the fuel screw greatly effects top end fueling and egt's. Right now I have my wastegate shut and hovers around 15-16psi and 800 egts going up hills so I got plently of egts to spare. I do not have headstuds, so I am comfortable staying at 15psi. I haven't decided if I will experiment the maxed out fuel screw and take it out for a test drive or wait until I get my ford 6.0 intercooler installed and hooked up, see what the pressure drop is and adjust/tune accordingly.
Thanks again for sharing the guide!

Glad to hear its helping people out! You mentioned the higher rpms, that is a side affect of adjusting the minimaxx in. This adjustment increases total fueling a bit, but also moves the fuel curve up higher in rpm range where its really needed on a turbo idi, because of the extra fuel up top and the extra tension on the governor spring most will see an increase in max governed rpm which is why some people have to lower their idle after the adjustment. As for timing, any adjustment will affect overall timing with the injection pump. Punching out the return fitting will advance it about 2* overall, so most people just retard the pump a dimes width if they do not have access to a timing meter. Get the pump timing where you like it, then adjust the face plate until youre happy with that. If you are looking at it from the driver's side of the pump, start by turning it clockwise a bit.

Sounds like your pump is making plenty to be making that kind of boost, I think youre right on by leaving the fuel screw alone until you get an intercooler in. Keep us posted!
 

Oledirtypearl86

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I know today I went and got an 85 F-250 supercab and pulling it back was a huge difference I hit 15 psi and the temps were climbing kinda scary I need to back it off a little also o noticed my water temp climbed a bit but I'm sure that's part of tuneing it also I maxed it all the way and I have the radiator airflow blocclked for the cold
 

Black dawg

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Related question:
Anyone know much about shimming the governor spring? I've heard that it's a viable option for higher RPM defuel vs using a 6.2/6.5 spring. What I need to know is what's the ID, OD and thickness of the shim supposed to be. I'll see if I can just make one at work and try it out.

I only messed around with shimming one, and it has been a long time, but it seems like .100 gave me 2-300 rpm. Wasn't trying to get above the standard 3400, had one that would start to defuel by 2800 and done by 3k.
 

Goose_ss4

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So I have and old international book with a whole chapter on pump tunning and calibration. Would anyone be interested in me posting them up? I don't know if we have a copy right issue here but...
 

Thewespaul

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So I have and old international book with a whole chapter on pump tunning and calibration. Would anyone be interested in me posting them up? I don't know if we have a copy right issue here but...
I spoke with @snicklas about getting some of my manuals scanned in and uploaded, unfortunately it’s still a copyright issue. He said uploading a picture here and there to answer someone’s question is fine, but uploading full manuals would attract too much attention
 

jetfly12

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Retarded the timing a dimes width and the results were less clatter and about 2 psi more boost. So I decided to throw together a small video project with the results, I had found a 35 to 70 clip from a few months ago that motivated me to go out and get another 30 to 70 mph run clip after the adjustments. I have ran into one small issue Wes and maybe I just need to run some ATF and unstick something in the pump, but when I downshift the ZF5 and engine brake rolling downhill, foot off the pedal, the engine will lurch sporadically, I wanna say somewhere above 1500 rpms and up. To avoid I just shift to neutral and use the brakes instead. Sometimes decelerating on flat ground too. Any ideas? Thanks!
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Thewespaul

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Looks like it’s running pretty good, it’s cool to see a before and after video.

I’ve run into this issue myself and I have it happening on the shop truck when I wind out 5th to 3500-3700rpms and let off. When I make a pull in that gear up to that rpm, I am dropping fuel pressure with my 105p and the truck will stutter until the housing fills back up with fuel. You won’t notice it when wide open throttle most the time unless you totally loose pressure, you will just slowly loose power the longer you hold it.

I’d try changing your fuel filter to see if it fixes it, otherwise look into maybe a lift pump upgrade or putting a stock return valve fitting back in. If you don’t have one I can set you up with one, I have plenty here.

The surging can be annoying but I live with it for now until I can find time to add a second lift pump in, but this is why I recommend a fuel pressure regulator with this mod, the pump doesn’t like to have a fluctuating fuel pressure fed to it, with a 105 gph pump I hold 7 psi steady until 3000 rpms where I start dropping pressure. I have the stock pump pretty much maxed out so you may be fine with a 105p, you can get them for around $70 if you shop around a bit.
 

jetfly12

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It is running great and it is more fun to drive! Makes total sense that it is happening to me not having a regulator in my fuel system. I will tackle the problem once I have free time, and I will let you know if I ever need another return valve if I still have problems, but I will wait till I try out a 105p pump first, I see what you are talking about all over the internet, with regulators included. Those seem better and cheaper then the facet 40222 anyways!
 

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