I searched around a bit for info on the pink top 22# injectors but didn't find much. I got these injectors with my TPI swap and they run great and have no problems with them. But after seeing the video of original injectors VS the Bosch IIIs found at southbay it got me thinking but I wasn't sure if it would be much of an upgrade from the pink tops. Were the pink tops any better than the factory injectors as far as spray pattern or were they about the same?

This is a shot of the pink tops on my setup. Don't mind the heat wrap on the fuel rail. It was an attempt to lower fuel rail temps on heatsoak.

 

Almost ANYTHING puts out a better spray pattern than the Rochesters.

GM was particularly concerned, it seems, about the possibility of blockage; so they sacrificed ALOT of other characteristics in favor of that. Which is kind of typical of how design decisions in general, in the world at large, end up. In the case of injectors, after all, you have to have small holes to get a fine pattern; and small holes are easier to clog than large ones. (ya think??)

Unfortunately GM also cheeeeeeeeeeeped out on the electrcial part too, which is what usually fails.

AFAIK the Bosch injectors have about the best spray pattern; but are more prone to clogging.

 

Just going to put in my 2 cents. I Think that i am going to have to disagree with you on the bosch injectors prone to clogging. 95% of our inventory consists of bosch injectors. Reason being, we have found that they are the most efficient and reliable product out there. Out of the thousands of injectors that we have sold, clogging was never an issue though we have seen a couple leak here and there..though it is very rare.
LilSki the pink top injectors are bosch. They are the "gen ll's". They have a 4 spray pattern and atomize the fuel extremely well. If they are functioning without a problem, no reason to invest in a different set.

 

I didn't say "prone to clogging"; I said

specifically in comparison to Rochester

per the OP's question.

2 VERY DIFFERENT things.

 

OK sounds good. The little I did find about them said they were an improvement over the OEM injectors but most of that info was pretty old. So I wasn't sure if there was much a difference from a modern injector. Although I may be close to the edge with the 22# injectors with my power output. I will leave them unless I start to have issues. Then I will upgrade to a set of 24# bosch IIIs.

Thanks

 

Neither your injectors, nor the Bosch ones, have changed much in the last 25 years or so....

 

exactly. Sorry, response was for LilSki

 

With an LT1 cam, I guarantee you're not close to the edge with your 22# injectors. If they're functioning properly, leave them be.

 

Injectors are rated on how much fuel they flow in pounds per hour. So how much fuel does your engine need?

Providing the engine can burn it at an optimal A/F ratio, the amount of fuel it needs depends on how much power it has the potential of making. The BSFC measurement is 0.5 lb/hp/hr.

Lets say a modest 350 can make 300 hp which which be a good street engine. 300 x .5 = 150 lb/hr. Since you have 8 injectors providing fuel, 150/8 = 18.75 lb/hr. The 22# injectors would be more than enough.

So how much power can 22# injectors provide? 22 x 8 / .5 = 352 HP.
24# injectors? 24 x 8 / .5 = 384 hp

These numbers are all maximums which you're rarely reach while driving on the street.

If your engine isn't anywhere near those limits then upgrading to a larger injector won't help. Putting in 24# injectors into an engine that only makes 300 HP won't make it go much faster. It will flow more fuel during the same duty cycle but if everything is working properly, the ECM should cut back on the extra fuel depending on what it's reading on the O2 sensor.

 

With the 305 my idle injector pulse was around 1.3 ms and now it is around 2.5 ms. A few injector calculators seemed to show I was around the top end of a 22# injector. And I figured since the LT1 came stock with 24s then that is where I should be at since I'm basically running an LT1 combo.

I don't expect it to go faster with 24s I just figured it is where I should be at my power level. And a retune wouldn't be a problem as I run a megasquirt.

Edit: but apparently those calculators are wrong. I won't mess with it if you feel I'm nowhere near the max of the 22#ers.