DB 4911: 6.5 Injectors Or "Hi Pop" Injectors?

[Duncan Sterling]

I just picked up a DB4911 core for a good price and hope to get it rebuilt/exchanged soon.

I've searched through old posts for this but it seems like there are alot of differing answers.

This is for an NA 6.2 on a '91 Suburban with a "J" motor, a Banks Stinger kit and around 120k on the clock. So the question is, when I get around to doing the pump, do I go with:

1) Rebuilt stock injectors?

2) Rebuilt 6.5 injectors (same as the stock HD '91 6.2 short/fines that I have now?)?

3) Marine/Hi Pop injectors (or are these for use with a different IP altogether)?

Also, if they're in good enough shape, can I use my stock fuel injector lines in all of these cases? If they fall apart or are in bad shape when I remove them (they have at least surface rust in most places) what should I replace them with?

Will I have to turn the pump down if I don't install a turbo along with the new pump (Banks says I can have a turbo kit minus the stinger parts I already have for the "discount" price of $1500)?

Is there anything else I'm not thinking of here that I should be?

TIA,

--Duncan

[john8662]

Hopefully you won't need new lines, otherwise you'll need another set from a 6.2 or 6.5 mechanical engine. The line connections on the 4911 are the same as on the common 6.2 pumps.

As for the injectors, I vote stock 6.5 TURBO injectors (there is a n/a variety).

If you're considering hi-pop's, consider where you get them. From what I'm hearin' the hi-pops sold on ebay are nothing more than regular 6.5 injectors shimmed to a higher pop pressure. These won't help anything, just more strain on the injection pump to pop them. The injectors sold by vendors on here offer true marine hi-pop injectors, with a larger volume tip/nozzle.

Thats good that Bank's is cutting 500 off for the exhaust system.

You might have to turn the pump down if running N/A, but since you have the stinger kit and are getting more air into the engine, it might not smoke that much. I think it's better to install all of it at the same time.

You won't need the snorkel and air cleaner part of the stinger though, hey, come to think of it, I might...

J

[rwpierce]

I am running a DB4911 on my Banks turboed 6.5 that is in my ' 84 K10 and just installed Heath's HO injectors. I took out 6.5 injectors that only had 20,000 miles on them. The engine is consideredly smother running,pulls stronger,and less black smoke when you get on it. I'd rebuild the 4911, turn it down 1/4 turn since you are not turboed yet and since you are getting new injectors go the extra expense with the Heath HO injectors. Your injection lines should be fine.

[john8662]

Turning the pump up or down with the 1/4 turn method isn't exactly the most accurate way to get the amount of fuel you desire.

Yes, this turns up the fuel, but how many mm^3 are you really delivering?

The point that I'm trying to make is that the 4911 pump will be calibrated on a pump stand to deliver a certain amount of fuel. If you take and turn down that same (already carefully calibrated for delivery) pump 1/4 turn, you won't know where the setting is. This becomes important when you turn it back up again, You may align the allen wrench the same way and then turn it 1/4 turn clockwise and think it's exactly where it was before. I beg to differ, it may be more or may be less. But I don't think that we can get it exactly where it was when it was calibrated on the pump stand.

This is why I still vote to install this pump with the turbo, less hassle that way. And you'll get more of a night-and-day difference in performance to compare to when it is finally turbo'ed.

J