I have a gmpp exhaust, K&N Intake with Stage1 kit previously installed. Would a 2.9" pulley be ok to run with my 42.5# injectors and the PCM flash from my stage 1 kit?

 

IMO yes. I was even tuned on 42 and a 2.9 with no cooling mods and still maintained good iat temps on the road and during dyno pulls.

I would suggest getting a tune as well. Personally i would just get 60's and a 2.8 along with a cooling mods then get tuned.

 

Not meaning to bash you but i think you need to rethink what you said.

1. 42lb injectors + 2.9" pulley, your injectors are going to go static....or damn well near it.

2. 42lb injectors + 2.9 pulley....you suggest getting a tune? Theres no suggestion needed, you NEED a tune.

 

yea. my next step is to get zzp's stage 3 kit and get hptuners and get it tuned. thats what you should do. i would just get 60's to be safe, get a 2.8 because 2.8 is safe. i would get cooling mods despite what people say. cooling mods are ALWAYS good. and the tune.. like someone said.. is a NEED! idk wat your looking to spend but when you plan to do smaller pulleys and all that ur looking at probobly over a grand... ive done the math and for what im gonna eventually get its gonna run me a little over a grand withOUT the custom tune. its around 600 dollars for the zzp stage 3 without the tune and then 500 i think for hptuners and then from there you have pay somebody to tune your car. so it isnt cheap. you should save it ALL up at once and then do it.

 

He asked if it was safe to add a 2.9. I said yes but recommended getting a 2.8, 60 and getting a tune instead.

Putting on a 2.9 is safe and he can still get tuned on top of that and run without cooling mods. How do i know this. I ran that setup and monitored it with HP Tuners.

 

ive been running my balt with 42# inject and 2.9 pulley for about a year now no issue...imo its safe

 

what was your IDC?

 

I researched this before I bought my parts for my car actually. From what I read and IMO 60's are the best choice when going to a 2.9. That is the max for the 42's to handle but it can be done and safely. However, since most people decide to get more power they just put 60's to be safe. Then with 60's a tune. Like I said this is what I gathered.

 

My personal experience, was even with a tune my injectors would go static around 5,500 rpms. 60s with a harness aren't that expensive so I upgraded and am very pleased I did. Safe insurance so to speak

 

just dont raise your rev limiter

 

Over a year on a 2.9/42 setup, have ran consitent mid 13's and put down great number's with such too.

On a "2.95" now, not that it's drastically changes much.

7k limiter on the last post's note.

 

I agree i was on 42' 2.9 pulley and tuned by BYT and car ran 13.4@104.1. Injectors where hitting 90ish on idc but IAT2 where below 120 on pulls at the track.

 

Same here, but with a 2.85" Pulley....
Thought I hardly ever get on it, and I did
calculate that my injectors are really close to
maxed out when I really get onto it. But they
keep up alright.

 

That's weird, because mine maintain a AFR of 10.5 - 11.0 even going ABOVE 5.5KRPM
If the injectors are static, at 5,500 rpm, youd start to lean out, as more air comes in and the same ammount of fuel is going in.

 

i did start to lean out hence why i upgraded to 60s

 

ran a 2.8" pulley with the 42.5's for years and 108,000km with zero issues

 

i run 42 on 2.8 and no issue...so i will put some 60's this week to be safe

 

2.9 and 42's were put on at around 30K miles. Almost 3 years and now at a 55K miles no issues.

 

I had a 2.9 on GMstage2 for about six months with no probs, but IDC's were at 114% at 6,000rpm. Totally lost power by redline. After the tune, it was much better.

 

To OP do you plan on trying to get more out of your car later on? I think that is the main question. If you feel you may eventually just get 60's you will be much happier.

 

ok as i read its ''ok'' to run 2.8 or 2,9 pulley on 42's but what kind of tune is really appropriate...simply the hpt and trifecta without a wideband can do the job??or a really good dyno tune with a wideband....?

just ask that because someone twell me that im really not safe to run my setup only on hptuner tune

 

Ok so ya, I did an interceptor record...
at 6500 rpm (I thought I went to 7,000 but in 2nd gear **** goes too fast sometimes)
my AFR stayed at 11.3 the entire time...
My Injector PW went up to 18.2 mS

 

What's IDC?

 

Injector Duty Cycle. We monitor it with hp tuners to see how our injectors are preforming.

 

Who told you that?! Complete BS. A HP only tune is perfectly safe.