Matty

That's about sums it up.

Boost Fr33k

ive heard so much about 42lb on a 2.8 thats why i decided to go with the 50lb injectors. not a big difference but hopefully my IDC wont be over 90% or 100!

CTCOBALTSSS

You got it bud. That's what I did.

articzap

I'd upgrade injectors. I believe my friend said hes at like 98% idc with his gm stage 2 and 2.8.

dervin3

I'd like to throw something in on this also. I've been watching this thread because I too an about to upgrade to a smaller pulley for my stage 2 and am undecided. I've gone away from the 2.8" because seems most likely the 42lbers will be maxed out and the car will most likely be really lean. What I would like to know is if the 2.85" as stated previously in this thread would be safe or not on 42 lb injectors or should I do the 2.9"? Would .05 of an inch in diameter make enough difference anyway?

Matty

It won't be lean. The debate on this issue is the IDC going past 90% with the combination of the 2.8/ 42.5# injectors.

dervin3

So you're saying I'd be safe with a 2.85"?

sealy

I've been watching this thread and looked at many other past ones too about this topic. It seems like so many are using 2.8 on stage 2 injectors... Then there are people saying that the injectors are "overworking" or can't supply enough.

I don't know, it would be nice if someone had the answer. I'd be safe and stick with the stage 2 pulley unless you would upgrade your injectors.


I'm probably sticking to stage 2 pulley when I get it, although 2.9 is mighty tempting.

Matty

You won't run out of fuel. My wideband said low 11's with the stage 2 tune and the 2.8".

The issue is Injector Duty Cycle and the possibility of the injectors going static (staying wide open). Nobody has had a problem with this that I know of, but there are opinions that it is just a matter of time.

Being safe= stock 3" pulley
Taking a chance= 2.8"

Safer with a 2.85. Safer yet with a 2.9.

dervin3

Thank you, just what I wanted to hear. I'm getting the 2.9 now. Headed to the dyno on the 30th to see how it does. Hopefully I'm not already lean because in the past week I've probably thrown P0171 ten times...hopefully that's just my K&N intakes MAF sensor placement.

tcolli17

Ok, here is the answer. Nobody can tell you because every car acts differently. Now that being said, be smart and get an aeroforce interceptor and a wideband. With those you will be able to tell if the 42's and 2.8 combo work good on your car. And I dare to say that anybody that melted a piston did not have a wideband.

Matty

No sweat.
Hopefully the dyno has a wideband connection to watch all areas of the RPM range.
Make a thread after it's done.

Edubs

Shortbus,

Got a question for ya. I was talking to someone about this very same thing and they asked me how HPT can say the injectors are running over 100% IDC. Can IDC actually be measured past 100%?

3fo893013L

Yes, HPT does measure injector duty past max.