I need to buy some injectors but I can't afford the acdelco injectors at 90 dollars a piece

I saw that southbay has a set of boch II injectors for 205 which is way more affordable, are they good? Reliable? I know they've been a sponsor for quite awhile

 

I put a set of rebuilt bosch injectors from Southbay in my 89 formula 350. 2 or so years ago now. I run ethanol free 90 octane. I can't recommend them enough, great customer service too. I pinched a fuel o-ring on install and they sent me a handful in the mail no charge. They used to have a coupon code for forum members - try code "tg11" (without quotations) and see if it saves you a few bucks. Good luck

 

Used them years ago without issue, they've always been the company to use for this forum

 

Agreed. They're really good. Wouldn't hesitate to do business with them again.

 

Nothing wrong with the Bosch IIIs from Southbay except the voltage offsets don't match the factory injectors so you might need a tune to compensate. If you don't want a hassle, get the Delphi injectors from Southbay.

 

Can't go wrong with them - great injectors and customer service. Some people say you need a tune for the Bosch III's but they ran perfect on my speed density 1990 305 tpi

 

Hmm, I need 19lbs/hr for my 305 and the only affordable option to me is the orange boch IIs
SKU 4024 on their website. So these aren't factory replacements?

 

Maybe it's like audio stuff or tv's where people can feel/tell the difference but i ran 19lb bosch 3's in my old 305 and 24lb ones, in the current engine, before it got turbocharged. If the voltage offsets were off, I sure couldn't tell the difference and car seemed to run fine for me. Both sets were from Southbay and I saved a bunch of money.

 

They are not factory replacements. Generally I'd only recommend the Bosch injectors if you're getting a tune or running aftermarket efi. The factory replacement injectors are the Delphi ones:

https://www.southbayfuelinjectors.co...d-305-tpi.html

 

And generally I'd recommend the Bosch 3's because I've used them in two different setups with no trouble or difference that I could tell. Just personal experience over a number of years and that seems to be echoed by a number of people. And that's regardless of whether they're factory replacements or not.

 

Just bought a set. Good price. Very helpful over the phone.

 

what size (#) do you need?
i have a set of very low mileage accel injectors that were in my 91.
theyre just sitting on a shelf now..

 

I need 8 19lbs/hr injectors, just need a stock replacement for my 86 305. Is accel a good brand? Are those injectors good themselves?

 

im pretty sure these are 22# injectors
accell is a good brand, lots of people use them

 

I installed a new set of #19 injectors from Racetronix and am very happy with them. What a difference from the old stock ones.

 

@Tuned Performance

 

I recommend southbay, had good luck with Accel and Holley too but Delphi are a direct plug and play if tpi.

 

I don't know if you have to spend a certain amount but my 400whatever worth of Delphi's from them came in a little zip up pouch which was a nice touch.


Regarding the tune/not stuff. I bought the more expensive Delphi specifically because I'd been led to believe they did not have
the same differences in opening time or voltage offset or whatever it is that the newer Bosch ones do as I did not want to
get into trying to tune this antique. Despite this fact I went from very normal INT and BLM to a system trying really hard to pull enough fuel to not be overly rich after installing them.
My conclusion, and after even more hours of digging through forums for people that actually know things instead of just
relaying experiences (which is perfectly valid and useful too) is that they are not in fact exact drop-in replacements
for the originals as is generally quoted. Whether this is an issue depends on two things, one is how observant you are and that isn't an insult
either some people are just more picky and notice minute changes more than others, two is your particular engine.
Mine is able to pull itself into a satisfactory mixture, more or less, but you can look at the data and
see that it's having to try a lot harder than it was with the stock injectors.
Take that for what you will, I have no personal experience with the later Bosch ones, maybe they are more-different,
maybe they aren't. They are certainly cheaper. I also did not experience any opening of the heavens or rays of divine
light shining down on my motor and making it run better than it ever has with new injectors. In fact if you'd swapped these new ones in
and not told me I'd have never known. 156K, ran fine before, runs fine now. Figured at the miles and for all the junk
people talk about these stock injectors it was due a set. I pulled the trans out a few days later for some other work
but there *might* have been an odd extended cranking time on the new injectors, nothing crazy but I thought I noticed
it a time or two. I've read that is a thing with the newer style Bosch ones as well.
My 0.02. I'm not a doctor nor do I play one on TV. You won't get that unless you're old.


Southbay was great to deal with though, I'd buy from them again and likely will.

 

@Mr Wolf
Could you lower your fuel rail pressure slightly to bring INT/BLM back to center with the replacement injectors?

 

That is a thing people do, both up and down pressure as needed. I've been told by tuners that across the board changes can
cause undesired behavior but I suspect it's back to one of those how sensitive are you/your motor situations. If I ever get
all the other forty year old car issues somewhat straightened out I might give it a go and see what it does.

 

my experience with the D3 is opposite they ran lean. A afpr cannot go lower than 3 bar. You can increase fuel pressure but if blm is 150-160 even 50psi isn’t enough to over come this.a simple on tgo you can get battery voltage offsets to compensate for the D3.

 

What is "Voltage offset"?

I ran B3's in the Kart during the 10x the tork take too, testing and they worked great and as you know, made great numbers (for what it was) i.e. it ran good. What was voltage offset'ing while that was going on?

 

Battery voltage offsets for what part number injector ?

 

These work well on 700 and 710 , in your test what was air fuel ratio ?
https://www.thirdgen.org/forums/diy-...0-voltage.html

 

What does that mean? "Offsetting" what?

The way that my brain works, to use the word "offset", You needs to have more than one "thing". You need at least two items or "things", so that one thing, is "offset", from the other....thing. What are the two things, that are offset,, from one another?

 

Read mikes explanation
https://www.thirdgen.org/forums/diy-...or-sticky.html

 

Yep...I don't "Get it". It must be NASA stuff. Are you talking about this part?....


The injectors operate on Battery voltage, to be more specific, what ever that is, in your car when it's running. They're literally, fed batt voltage from the injector fuse. The only "offset" from the batt to the inj is the resistance in the power circuit/harness, from the batt to the inj, and thought the fuse box. On the ground side of that circuit, a switch inside the ECM grounds the circuit. So....I read what ULTM8Z (is that "Mike"?) wrote, but it must be some magic **** going on in there somewhere, b/c "Offsetting voltage" in a circuit w/power, a load, and a switch to ground, doesn't work that way, w/in the realm of my schooling and experience.

Now....FLOW RATE "offset"; one injector flowing a rate different than what is programmed in the ECM....that makes complete sense to be "offset", and need adjusting in the tune.



^That, I "get". As Denzel Washington said, "Explain it to me like I'm a 5 year old"....

 

Yes great explanation, not sure how to dumb it down

 

By explaining how you "offset voltage" in a basic circuit w/12v, a load and a grounding switch. (?)




If "inj 1" and "inj 2" are both batt voltage, explain to me, where you're "offestting" that.... (?).


.

 

in the binary calibration

 

https://injectordynamics.com/article...racterization/

another good example

 

The injector battery voltage offsets table tells how much delay there is in opening and closing injectors according to battery voltage. With lower voltages you will have increased dead time for the injectors, the ECU will add this delay time to the injectors.

The concept behind the voltage offset is to account for the delay in fuel delivery as the injector opens. The lower the system voltage the more sluggish the injector will be in opening, the higher the voltage the sooner the injector opens so less adder is needed

 

BHR, Thank you. THAT was a succinct and clear explanation. A 5 year old could "get it"....and even I was able to, also.

 

guess i should of said it’s the black magic inside the box. HTH

 

While we're on the subject, my understanding is that most aftermarket efi systems pretty much just want to know the flow rate of the injectors and that's it.
Why do they get away with just that? I ran microsquirt on a turbo corvair with a gm throttle body and I don't remember it wanting to know anything more than the
flow rate of the injector either unless it was buried somewhere and I never saw it. What's up with the GM stuff needing more?
It can't be for the sake of precision on this old 8 bit batch fire setup can it? My understanding
is that the fuel table looks about the size of a checker board if that.

 

I agree. If voltage influences the rate at which the injector opens, and I'm sure that it does, that is effectively changing the PPH of that injector, vs. another. Seems to me that you could make other adjustments to accommodate that very....very small difference in flow per cycle.

I appreciate BHR explaining what the term meant. I learned a thing...or became aware of it. That's cool. While it's good to learn about and be aware of as many factors that affect a tune as possible, I think some of this tuning gets into the realm of "phile"....tune-o-philes, much like audiophiles argue over insanely minute details of sound/character, etc. From whatever speaker/amp...even gad damned wire! Yeah, maybe it's there, (whatever it is, that they're obsessing over), but does it matter? Probably not to most people. To ME, if a car starts, idles, runs good, has good responses and feels, and gets good gas mileage....I'm good. A carb can do that, so, maybe that recollection can bring some perspective to things. A late friend of mine used to "remind me", (about my profession) "THIS AIN'T BAGHDAD, KENDRICK!!" He was right.

 

The onboard mileage counter would be off if the ecu did not know fairly precisely how much fuel was being delivered I suppose. Mine seems a little wonky with the Delphi's and no software changes.
Not that it was especially accurate to start with but I noticed it.

 

Yep. I expect that changing the injector typically renders the mileage calc'er, useless. BUT...I think they're pretty useless anyway, and always hand calc, if I'm in a caring about fuel mileage, kind of mood.

 

When changing injectors on these cars besides the actual VE tables there are two offset tables and the flow rate that can be tweaked, the voltage offsets and the low pulse width offset vs base pulse width, the newer GM cars actually have a few more injector offset tables one being the actual temperature of the injector like the voltage when temp of the injector is cold or hot PW is offset. I don't have experience with the southbay injectors in terms of how they run without tuning as I never used them but I often see them on these TPI cars with the little adapters and wonder why? If I was in need of injectors for these cars I would buy the ones from them that state work with the factory calibration, buy original used ones, or clean the originals. From my experience I rarely see the originals fail but often see the aftermarkets having issues, dead, stuck open, and even leak from the body

A car can start, idle, run good, have good response and feels, and get good gas mileage but if you were to log it the numbers will tell a different story, the factory computers do have some leeway to compensate a rich or lean condition which most drivers would not be able to tell there fueling is on the borderline or off until the car is logged

In my circumstance I've tried to alter the offset tables to what the injectors call for or "what the internet says" they call for and it was a no go the car would barely idle so I had to do ALOT of trial and error

 

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