I would love for someone to do this. It would clarify A LOT of things.

 

this is an argument that will never end!!!! 42lbs & 2.8! ahh!! well im not adding to the dilemma but my friend blew his motor running this set up, but then again ive noticed that hp gains and engine realibility is never the same with lsj's. some ppl run fine and some people blow up.

my suggestion, like many, dont over do your injectors.

injectors duty cycle: GET SCANNED!

 

i did a 2nd gear pull, with the tech2 on the car. pulled 17 m/sec in a 20-70 run.

on stage 2.

now, not much of a load like 3rd or 4th gear, but you get an idea.

this was also with my stage2-100 octane map, so there is less fuel in general, but not as much as one would think.

17.0 comes out to be about 67%

 

But the GM stage 3 has a 2.8 pulley and no bigger injectors, does this mean that stage 3 is bad

 

Its not really a 2.8 pulley.... its bigger than that.
I dont remember the exact size, but it was actually closer to a 3.0

 

i ran a 2.85 with stock injectors for awhile until i received my tune and 60's. i didnt have any problems whatsoever but i prolly got lucky. who knows...

 

yeah, definatly lucky! haha!

 

You are right stage 3 76mm = 2.99in
Sorry my mistake
So i'd better run the stage 3 pulley instead of the 2.8 right ?

 

So that means like in your previous post where you and I agreed 42lb injectors WILL support a 2.8 pulley?

 

im not going to say yes, but im not going to say no. i don't want to be "that guy", that says "sure it's fine!"

then get flamed like none other. have i risked my car? yulp. not a big deal to me.

let me get some more time with a tech2 before i give a concrete answer.

 

We're thinking on the same page!

Two things I do believe one needs when you run a 2.8 and 42's, colder plugs and a tune.

 

i change pulleys so much, i just keep the 7e's in the car, and the laptop readily accessable to change tunes.


just a heads up kids, running too big of an injectors is almost as bad as running too little.

you can only take so much fuel out

 

Exactly.

I was reading over on another board, some believe that using 60lb injectors are actually STARVING the motor of fuel, and the reason why it is always piston #4 is because it is also furthest away from the entrance feed of the fuel rail.

Source of the theory; maxed out fuel pump.

Think about it, you guys are using injectors with a flow rate of nearly TWICE the rate of the stock injectors.

I don't believe that GM would use a fuel pump that would support double the flow rate during production.

 

I think the fuel pump is capable of handling the 60's its the fuel rail itself that is the limitation. As well I would rather be running injectors that are too big than too small, just my 2 cents.

 

So, if it's the fuel rail itself, what is causing it to be limited? Maybe cause the fuel pump can't keep up?

 

is it safe to run a 3.0 inch pulley on stock injectors?!? if no why?

 

physical space, I remember reading about this exact issue and zinner and wopontour had a discussion about the actual size of the rail. Saying it is restrictive. Increasing the fuel rail size should help get fuel to #4 faster without increasing fuel pressure.

because the IDC for the stock injectors on stock pulley is averaging above 120% from thelast 5 logs of stock SS S/C's that I have seen.

 

so the bottom line is its safe to to have 2.8 wit 42s wit cooler plugs and a tune or not

 

Read the thread moron.

 

IMO no...you can get a leaned out tune to get ur IDC down but thats a bomb waiting to go off. When I had 42's and a 2.8 anytime i went past 6000rpm i was maxing out my injectors and running leaner than I should have.

 

I read that also, but I still believe it has something to do with the fuel pump.

There is a guy trying to fabricate his own fuel rail, where the fuel inputs the rail between cylinder 2 and 3. What he is trying to do is distribute it more directly in the middle. Although cylinders 2 and 3 will still get the most fuel, the theory is a possible solution to our problems.

 

more than likely it will help, Im just pissed off that everytime I add a lil power seems i gotta change the little things that should be able to handle more power like the pump or rail.

 

They sell you a kit and warranty it with 4-5* of KR, so yeah......they are retarded depending on who you ask.

The GM injectors are not as good as the Bosch style injectors that are in the Intense kits. The IDC is higher from MY experience on the GM stage 2/3 injectors than on the 42.5#'s from elsewhere. But I can't speak for everyone.

FUELRAILS will OWN you down the road. Damn Fuel Pressure Probs!

 

Let's bump this back to the top.

 

2.8 + 42.5's = good for about 2 weeks.

the gm injectors can't handle it. pure and simple.
hell they can barely handle the stage 2 crap.


i wonder if there is a way to bump up the rail pressure. i know that the ecm controls that side of it. it doesn't give us the power in hp to do it.