3400 #36 injectors

[jabartram]

i want to upgrade my 03 3400 injectors and i've been reading through the many posts on the #36 injectors, and been looking for reman injectors but i'm confused, do all the 3.8's including s/c'd use the same injectors? i found some reman for an excellent price for a 2001 3.8? but i can tell if they are 36lb? there is a part number change between 2001 and 2002.

[MMGT1]

The 36's are a HUGE for an upgrade for the 3400. I have them in mine, and they are a bitch to tune! If you do the upgrade make sure the flow is changed from 2.68g/sec to 4.30g/sec to start with. You're fuel trims will have to be adjusted from there. As far as the difference between those two years I don't know. There is also wiring involved with the 36's but it's pretty easy. I do know the 3800's are 36's....mine are from a 98 or 99??? Anyway, Ben should be the one to straighten you out on this one.

[blackbombshell95]

Isn't there a 28lb injector that requires no modification?

[zofo61]

I have been told that the injectors from the 4.2 TrailBlazer are a direct fit, and they are cheap as hell from this site:

http://www.herkofilters.com/

Go to the inventory page and scroll down till you see the TrailBlazer application.

[jabartram]

does anybody know the flow rate for the 4.2 injectors?

[zofo61]

28 # but can go to 33# with pressure I think....I have the Part #s for reserch:
GM # 25313185
AC/Delco # 12569573
STD # FJ319

[jabartram]

so, the 2001 3.8 injectors should be fine?

[AaronGTR]

i want to upgrade my 03 3400 injectors and i've been reading through the many posts on the #36 injectors, and been looking for reman injectors but i'm confused, do all the 3.8's including s/c'd use the same injectors? i found some reman for an excellent price for a 2001 3.8? but i can tell if they are 36lb? there is a part number change between 2001 and 2002.

The 36lb injectors are used in the supercharged 3800 motors. The NA 3800's have smaller injectors, I don't recall what size exactly. Either way, they both use bosch style clips and will require you to modify your injector harness. The question is, what do you have done that needs such large injectors? Are you boosted at all? Have you scanned your car to see what the injector pulse width is? You should be sure you really need injectors first, and what size you really need. The 4.2L injectors from the trailblazer/envoy are a direct swap for your car and flow enough to handle most NA mods or low boost. Your stock injectors are rated 22.5lb/hr @ 55psi and the 4.2L injectors are rated at 28lb/hr @ 55psi. I would certainly go with the 4.2L's before injectors from a NA 3800.

[blackbombshell95]

Who has done the 4.2L 28lb/hr injector swap?

[TurboGt]

I have 33 lb/hr injectors on my 3400 and I got them form a Typhoon for like $50 for the whole set.

[xonelith]

Going with the 36'rs could be overkill. I"m running at only 50% duty cycle and I only have a cam.

The 28's are probably a better bet cuz it is a direct fit, and apparently the retainer clip is the same as the stock injectors. I bought the 36's cuz they were practically free and did most of the modifications with a few friends.... PITA!! And I'm not using the retaining clips (I don't recommend this).

If you are really stuck on the 36's, Milzy sells a kit that includes the injectors.

[jabartram]

ok, i think i'm gonna go with the 4.2 28lb injectors, what fuel pressure do you all recommend?

[MMGT1]

I have the 36's and still run the factory fuel pressures....

[AaronGTR]

Yeah, the 28lb injectors use the same clips and retainers and everything. In fact, they look exactly like the 22.5lb injectors except they have more holes in the tip. That's how close they are. Basically they will give you more fuel but be the closest to factory reliability and quality of idle and part throttle engine response, and they'll be the easiest to tune since they aren't too far from stock. Factory fuel pressure is fine. You'll just have to get a tuner if you don't have one already so that you can change the injector flow tables in the pcm (or have someone do it for you).

[prophiseer]

What kinda N/A mods are y'all running to be pumping such massive injectors? I'm either curious or confused, haven't decided.

I've been running 19# on my 3400 for the longest time and she runs like a deamon; maybe it's from running a multec1 setup . . .