I dont know how these will react in our engines, but they wont have the extreme injection duration like the 3m injectors which is what causes the high cylinder pressure that can break pistons.
Building a better db2
- Thread starter Thewespaul
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david85
Full Access Member
Not with this kind of atomization
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VERY interested to see how these perform. Apologies if you already answered this, but are you running the same pop pressure? Or were you able to lower it? I remember discussion about lower pop pressures as a way to increase the service life of the injection pump. Seems this could be the best of both worlds.
Its just a regular G code injector and spring assembly with a modified DI nozzle to fit in the IDI injector, this is a used nozzle popping at 1900 psi, I can run it plenty higher or lower but will likely just be running it at the stock pressures. I'm working my tail off trying to get caught up on orders and projects I got behind on when I had to drop everything to move the fuel shop, but I'm hoping to have some time in a few months to knock the dust off the shop truck and start testing some new products, excited to see how these would do in our engines.
IDIBRONCO
IDIBRONCO
Me too. This seems like a potential game changer to me.
Ferd_Diesel
Full Access Member
Not sure how I missed out on this post when reading this thread monthes ago and a db2 uprade kit is an awesome idea. So mechanically inclined can upgrade there own pumps. I have like 4 stock pumps laying around. Cant say this enough love what your doing for the community
Not the most exciting high output pump in the world, but with having the ability to do everything in house I’ve been able to develop some parts to really dial in the 90cc pumps and combat the bias these pumps have to higher outputs at lower rpms and trickling off where these engines make really good power. Here’s a recent one with 5cc of deviation through the entire rpm curve, all my 90cc pumps now carry this flat fuel curve, with the most being 12-15cc of spread through the rpm curve.
Also since I’m not on the clock leasing fuel shop space and equipment, I can take the time and make these pumps look the way I want them. With the vapor blasting cabinet I picked up from the fuel shop purchase I can remove all the blemishes from the housings and make some automotive jewelry from these 30+ yr old parts.
Still playing catch-up from having the fuel side of the business being down for months, but I have some exciting pumps in the works that are pushing these 2 plunger pumps well beyond I originally thought possible. Good stuff to come. Hope everyone is doing well during these crazy times.
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Also since I’m not on the clock leasing fuel shop space and equipment, I can take the time and make these pumps look the way I want them. With the vapor blasting cabinet I picked up from the fuel shop purchase I can remove all the blemishes from the housings and make some automotive jewelry from these 30+ yr old parts.
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Still playing catch-up from having the fuel side of the business being down for months, but I have some exciting pumps in the works that are pushing these 2 plunger pumps well beyond I originally thought possible. Good stuff to come. Hope everyone is doing well during these crazy times.
ih8minimumwage
Full Access Member
Well, I guess after I get my ZF swapped in and the 94 turbo installed I'll be in for one. Awesome work.
Macrobb
Full Access Member
So is that fuel curve from the 90cc pumps you have in the store? (I'm assuming yes)
Also, what are you setting the governor to? Is it possible to adjust for 'taste'? I mean, I like that curve, but I'd want it to cut off at a max of like 38-3900 RPM; if it's not pulling fuel at 4K(probably for demonstration purposes?), it would have to have the defuel point higher. And I've had some... issues with too high of an RPM before.
If we can get it set reasonably, I'll totally order one!
Also, what are you setting the governor to? Is it possible to adjust for 'taste'? I mean, I like that curve, but I'd want it to cut off at a max of like 38-3900 RPM; if it's not pulling fuel at 4K(probably for demonstration purposes?), it would have to have the defuel point higher. And I've had some... issues with too high of an RPM before.
If we can get it set reasonably, I'll totally order one!
Yes this is the standard now for my 90cc pumps, heres another two 90s Ive done since then for comparison
What kind of issues did you experience with the higher governed rpm? If you're just swapping the main gov spring out for a stiffer spring or shimming the factory spring without taking into account how that will affect the internal idle spring's relation to the guide stud you will definitely run into drivability issues. I set my 90cc pumps for full fueling to 4000 rpms as you can see in the graphs, after 4k you will have fuel start to cut back and level out to zero fuel, but with these governors defuel does not happen at a single point its more of a progressive drop since its replicating whats happening on the other side of the governor when dropping down to idle, which you want that to be progressive for an on road application.
Having a governed speed above 4k doesnt mean the pump is just going to want to rev to 4k all the time, in fact the higher governed speed is more because of the flat fueling curve, not the other way around. If you're in an auto truck you wont be able to see those higher rpms anyways, and in a manual truck you're controlling where the rpms go with where you're shifting, the pump will only go to higher rpms from stock if you leave your foot on the skinny pedal and never shift. Some of the Gm idi guys are running db2s with no gov travel at all, just a block in place of the main spring so there is no defuel in an attempt to keep as much fuel in the higher rpms as possible since a lot of those smaller displacement engines they are running up to 5k, even with that radical of a setup it has completely normal driving behavior when setup properly. If you want to be able to rev your engine up to defuel on every shift I can build a 90cc pump with an earlier defuel but you will lose the advantage of the flat curve because of the gradual defuel these governors have. Nothing unreasonable about a 4k+ governor setup, many pumps came this way stock from stanadyne, and its only a few hundred rpm higher than the factory max rpm setting.
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What kind of issues did you experience with the higher governed rpm? If you're just swapping the main gov spring out for a stiffer spring or shimming the factory spring without taking into account how that will affect the internal idle spring's relation to the guide stud you will definitely run into drivability issues. I set my 90cc pumps for full fueling to 4000 rpms as you can see in the graphs, after 4k you will have fuel start to cut back and level out to zero fuel, but with these governors defuel does not happen at a single point its more of a progressive drop since its replicating whats happening on the other side of the governor when dropping down to idle, which you want that to be progressive for an on road application.
Having a governed speed above 4k doesnt mean the pump is just going to want to rev to 4k all the time, in fact the higher governed speed is more because of the flat fueling curve, not the other way around. If you're in an auto truck you wont be able to see those higher rpms anyways, and in a manual truck you're controlling where the rpms go with where you're shifting, the pump will only go to higher rpms from stock if you leave your foot on the skinny pedal and never shift. Some of the Gm idi guys are running db2s with no gov travel at all, just a block in place of the main spring so there is no defuel in an attempt to keep as much fuel in the higher rpms as possible since a lot of those smaller displacement engines they are running up to 5k, even with that radical of a setup it has completely normal driving behavior when setup properly. If you want to be able to rev your engine up to defuel on every shift I can build a 90cc pump with an earlier defuel but you will lose the advantage of the flat curve because of the gradual defuel these governors have. Nothing unreasonable about a 4k+ governor setup, many pumps came this way stock from stanadyne, and its only a few hundred rpm higher than the factory max rpm setting.
Macrobb
Full Access Member
If your throttle cable is sticking that’s nothing to do with the pump, but if anyone has something like that happen just turn the key off and fix the cable. Rocker arms coming loose is an issue I’ve seen with even stock trucks, I use blue locktite on the bolts and haven’t had anymore issues with it, these engines vibrate ALOT. Defuel is 4300-4400 on these.
You sure can, just as long as you have a pyro and aren’t expecting a smoke free exhaust while na, I’ve have several customers run 90s on na trucks while they build turbo kits and work out bugs on fresh projects. I do not recommend running stage ones with a 90cc pump, save your money and get stock injectors. These injectors are pretty big already and without running a 100cc+ pump you’re really not going to bet anything.
Custom 110 pump Im putting out for a local customer they are putting on another stock IDIT shooting for 300hp, knowing this is going on a stock engine with stock headgaskets, ideally I would want a pump that makes less fuel in the lower rpms where the engine cant efficiently use big fuel which creates high cylinder pressure we want to avoid. I took some of the tech from the the flat fueling 90cc pumps and applied it this 110, started out making not great fuel but with a lot of dialing, manipulating the advance curve and running a little different governor setup so the flyweights are actually overcoming the main governor spring at lower rpms but not at higher rpms, I was able to get the pump to make less fuel down low and peak fuel where we expect peak hp to be, while still retaining a leaf spring and adjustment up to a 130cc at 2800, and an advance curve still within the factory spec.
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Another custom pump today, for one of our oilburners. Dont know if to call this a 130 or a 145 pump, but this one is built up with locked timing, big input thrust bearing and some neat features. Below are three fuel curves compared to a stock na pump, first is our valet mode which cuts down the fuel basically to stock, next is the regular street driven setup at 10 psi inlet pressure, and the last is the full fueling setting at 40 psi inlet pressure. All settings are within stanadyne spec for transfer pressure and a pretty stock idle speed, between 7-800 rpms depending on the fuel setting.
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