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Does any one know where to buy genuine Bosch 311 injector nozzles?

spdgofast

spdgofast

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I'm looking to buy some 311 injector nozzles, the last set I bought on ebay but I can't seem to be able to find genuine Bosch nozzles. I don't have the Bosch part number so if anyone has that it may help.
Any help is greatly appreciated.
 
Last edited:
Big T said:
For $50 just buy the whole injector from Leroy. I put them in my ‘99 as is and they were good to go.
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That is the best most people can do.
The reason he wants the Bosch 311 is they produce better mpg when putting around, and better power when mashing the fun pedal.

These are the injectors that people did dyno testing on and showed gains of 40hp years ago. Since then the B.S. sales places claimed +40 on other injectors because not well educated buyers knew there was something to buy but didn’t know what.

Then the last advantage is they have a history of outlasting normal injectors.
I tend to recommend injectors at 100,000 miles- but in the feet we constantly got 150,000 miles from the 311 without any degradation in numbers. Sometimes over 200,000. So the higher cost they came with was justified by longer life.

For people not after every bit of power, but longer life or just better mpg-
You can run higher pop pressure from these and get the normal volume of fuel output. The higher pressure makes better fuel misting which causes increased mpg and a cleaner burn. That cleaner burn also helps people that have high mileage and fail emissions tests on hc, but you can do that with normal injectors if needed just to pass the test, then slip in the normal injectors- I mean- if you want to break the rules and kill the poor spotted tree whales.184A41EE-B6A0-4FA7-AED3-F951C4E64AA4.png
 
Will L. said:
That is the best most people can do.
The reason he wants the Bosch 311 is they produce better mpg when putting around, and better power when mashing the fun pedal.

These are the injectors that people did dyno testing on and showed gains of 40hp years ago. Since then the B.S. sales places claimed +40 on other injectors because not well educated buyers knew there was something to buy but didn’t know what.

Then the last advantage is they have a history of outlasting normal injectors.
I tend to recommend injectors at 100,000 miles- but in the feet we constantly got 150,000 miles from the 311 without any degradation in numbers. Sometimes over 200,000. So the higher cost they came with was justified by longer life.

For people not after every bit of power, but longer life or just better mpg-
You can run higher pop pressure from these and get the normal volume of fuel output. The higher pressure makes better fuel misting which causes increased mpg and a cleaner burn. That cleaner burn also helps people that have high mileage and fail emissions tests on hc, but you can do that with normal injectors if needed just to pass the test, then slip in the normal injectors- I mean- if you want to break the rules and kill the poor spotted tree whales.View attachment 76986
Click to expand...
I had the “Marine Injectors” purchased from Heath in the ‘99 Suburban. Also had the Heath tune. They produced substantially more smoke and lower mileage. I have 3.73 gear ratio and got 16 mpg Hwy vs 18 mpg that the other two Suburbans got with stock injectors and 4.10 gear ratio. Based on seat of the pants feel, I would say slightly less horsepower. They were always a PITA to pass CA smog. Finally, they lasted 100K miles and were done.
 
Big T said:
I had the “Marine Injectors” purchased from Heath in the ‘99 Suburban. Also had the Heath tune. They produced substantially more smoke and lower mileage. I have 3.73 gear ratio and got 16 mpg Hwy vs 18 mpg that the other two Suburbans got with stock injectors and 4.10 gear ratio. Based on seat of the pants feel, I would say slightly less horsepower. They were always a PITA to pass CA smog. Finally, they lasted 100K miles and were done.
Click to expand...

EXACTLY.
That is one of the places I was talking about that sold the he SUPPOSEDLY better injectors, and why those who understand the difference of getting the better ones and setting them according to your desired application.

The fact that you had the set up from Heath and it was all worse- didn’t do anything advantageous to your situation- does that say anything to Heath’s sales and marketing schemes?

Just throwing parts on and getting what someone else has doesn’t mean it is right for you. From what I remember when I drove your suburban it also had an ATT.
Was the ATT after that debacle or part of it would be my first question.
What did you tell him you were trying to do by him giving you a hot tune and his fuel dumper injectors would be my second.

Someone here asked what are “STOCK” 311 pressure. And the response of 2100 is as given. And that is correct for a single engine boat that runs constant 3800 rpm fed from a db4- because that is what they were released for.

If someone wants more fuel, all across the board, which will obviously lower mpg and drive ability on an otherwise stock engine- yeah 311 @2100 will do that. And the knock-off injector tips that don’t atomize as well are gonna do it worse and smoke some at the same time.

I haven’t done pop testing with this new fake fuel we have now. It is a different viscosity than original #2 so the old pressures are not going to produce the he same results.
Guys that do wvo learn to adjust their pop pressure according to their fuel recipe. So I can’t say anything to a good pressure with this fuel we have now. But I used to swap out stock new injectors for 311 set to 2350 and the power AND mpg increased while still passing emissions- and infact were cleaner emissions from about 1200 rpm up.

We ran them into the 2700 psi range and still had factory power levels with much improved mpg and improved emissions.
As to the knock off stuff different than laces sell- sometimes it works and sometimes it doesn’t
 
Will L. said:
EXACTLY.
That is one of the places I was talking about that sold the he SUPPOSEDLY better injectors, and why those who understand the difference of getting the better ones and setting them according to your desired application.

The fact that you had the set up from Heath and it was all worse- didn’t do anything advantageous to your situation- does that say anything to Heath’s sales and marketing schemes?

Just throwing parts on and getting what someone else has doesn’t mean it is right for you. From what I remember when I drove your suburban it also had an ATT.
Was the ATT after that debacle or part of it would be my first question.
What did you tell him you were trying to do by him giving you a hot tune and his fuel dumper injectors would be my second.

Someone here asked what are “STOCK” 311 pressure. And the response of 2100 is as given. And that is correct for a single engine boat that runs constant 3800 rpm fed from a db4- because that is what they were released for.

If someone wants more fuel, all across the board, which will obviously lower mpg and drive ability on an otherwise stock engine- yeah 311 @2100 will do that. And the knock-off injector tips that don’t atomize as well are gonna do it worse and smoke some at the same time.

I haven’t done pop testing with this new fake fuel we have now. It is a different viscosity than original #2 so the old pressures are not going to produce the he same results.
Guys that do wvo learn to adjust their pop pressure according to their fuel recipe. So I can’t say anything to a good pressure with this fuel we have now. But I used to swap out stock new injectors for 311 set to 2350 and the power AND mpg increased while still passing emissions- and infact were cleaner emissions from about 1200 rpm up.

We ran them into the 2700 psi range and still had factory power levels with much improved mpg and improved emissions.
As to the knock off stuff different than laces sell- sometimes it works and sometimes it doesn’t
Click to expand...
Prior owner of the vehicle had the Bosch Marine and ATT installed. I bought it shortly after and that was 2010 and 150K miles. Those are my only reference points.

We believe the greater flow of the marine injectors caused increased smoke. Hwy mileage ranged from 15.8 to 16.5. On the other Suburbans with stock injectors, the Hwy mileage was 17.5 to 18.0.
 
My unproven theory on injector pop pressure is that its used to adjust fuel duration and has nothing to do with making them "mist" more for a better burn.

If you take two of the same nozzles in an injector an sent them at different pop pressure they will flow the same amount of fuel because the IP is responsible for fuel volume (I've confirmed this on a test bench) But the higher pop injector will flow the same amount of fuel faster. So if the pump volume is increased it will also increase the duration since it need more time to flow the extra fuel. So pop pressure is then raised to shorted the duration back to spec .That's why in my opinion higher volume marine pumps used higher pop pressure, it put the duration back in spec. Also shorter duration makes more power with the same fuel volume so I believe this is the performance increase most people notice when "upgrading" to marines.

The better "mist" is a side effect of raising pop pressure but you need to understand how a IDI operates. Combustions starts on the prechamber walls because the high velocity swirl pushes fuel to the outer walls of the prechambers. Once the Initial combustion starts the injector will continue to spray fuel as the engine passes TDC and reverses flow. The injector is still spraying past TDC as the piston starts to go down. The Pressure differential at the cut throat atomizes the fuel as is goes from the prechamber to the man combustion camber. There is no need to for better atomization from the injector since the prechamber is already doing that. If anything you want bigger droplets of fuel that way they can break down passing though the cup throat, instead of burning up in the prechamber. This is also why I believe diamond cups are pointless and are for emissions control but I wont get off subject here.

Now I could go on for a while about pintle designs and all that but that's a conversation for another day. But I will say this..... in my option marine nozzles are not the best design. Much like the stock injector, the flow rate curve on the marines are designed more for emissions than making power. I will be running a modified set of long bodies on my build. Not only do they have the more lift than the marines they use a bigger diameter needle. The real magic is the pintle design though, that's why I picked long bodies over marines.

Marines got popular for all the wrong reasons, now that's all people want to run....
 
Marines are still a good off the shelf upgrade, much like that 6033 DS4 you call a "Beast" pump. But there are better options for those of us who actually build custom stuff.
 
Rockabillyrat said:
Marines are still a good off the shelf upgrade, much like that 6033 DS4 you call a "Beast" pump. But there are better options for those of us who actually build custom stuff.
Click to expand...
You think you have it all figured out still. But you are all talk and no truck.
 
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