Well, doing a tune up and installing smaller injectors. I found part of that "wall" that everyone talks about.

Before, with my 19lb injectors, my engine would rev to 6k and a little after with little to no problems.

Today, after installing 17'lbs, new wires, cap, rotor, wirewheel my plugs, check gap, check vacuum. I took it for a drive.

It only seems to want to rev to about 5-5500 now before it starts choking and having problems. However, i got some of my low end grunt back to where I can bark my racing tires again.

So, you want them high rpms, you need more fuel up top, along with the better airflow as well.

 

this is actually a good post, i was wondering with all the modifications i'm planning for my 3.4 if i would need 19lb or 17 lb injectors

i'm kinda confident 17lb will cover it, since i rarely rev above 3-4 grand

 

kretos, you have 17# injectors stock, the 2.8 and 3.1's have 15# stock and the 3.4 have 17# stock

 

yep i know, engine was just a long block so no injectors with it, need to buy them

 

19 is way to much, even with headers, slight porting, 1.6 rockers. All this is on a stock prom chip also.

Stay with some 17's, and maybe shim the fuel reg, or get an adjustable regulator.

 

the 2.8s have 13# injectors, not 15#

 

actually the 2.8 ones are 15, its a common misconseption

 

i was doing a search to find what injectors came in a 2.8, wow it seems no one really knows, lol. any post that gets on that subject goes back and forth and ends up w/ no definite answer.

 

I orginally posted 13 for the 2.8. But that was a wrong calculation.

GM list 2 different part numbers
aftermarket list the same.

So really, I guess it is 15's. As well as tomp put 3.1 injectors in his 2.8 and passed nj inspection/sniffer.

 

every part number i have seen from the dealers shows them as 15# injectors for 2.8's and 3.1's. i personally have 17#ers i picked up for 20$ in a private deal.... found that it runs a little rich at idle, and pretty dead on at top end, but that is with my setup that i have currently. i am more than likely gonna have to go bigger with the addition of a new cam and valvetrain.

dale, that new trueleo intake really eliminated that "wall" for me. thing is running better now than ever. she'll turn 9's for sure now in the 1/8th.... just a matter of where at in the 9's will she run. oh yea and i am not ported or polished..... yet

 

2.8L definitely uses 15pph injectors.