i just got a car with these mods. Does anyone have this combo and have u experienced any problems with it??? would love ur input. Im thinking about just replacing the pulley with a 2.9 pulley to be on the safe side. whatcha think?

 

get the 2.9... many people, including myself, have ran the 2.8 but we didnt know the things we know now.

 

did u experience any problems at all?? Or u just replaced to be on the safe side?? And did u haveta retune the car???

 

From what i have expiernced with hp tuners, adn different injectors, your duty cycle with a 2.8, will be maxed out, when i was runing a 2.7 with 42's my idc was 122% by 5,000 rpm, with a maxed out duty cycle your injectors can go static, which can be bad, if you want to be on the safe side throw on the 2.9, but you can run the 2.8 there is just a what if.

 

i was running my 2.8 with 42's and i didnt have any problems. when i threw on my exhaust and got a tune i was still good. Before i got my tune my injectors maxed at at like 92%

 

Ive been runin a 2.8 and 42's for over 6 months with no problems

 

how long can you run either a 2.8 or 2.9 inch pulley before seeing any problems? how many miles down the road will this affect your car even if you baby it?

 

I've been on the 2.8 pulley with Stg 2 tune for almost a year now with no problems, and another local balt is going on 7 months with the same set-up, also no problems. His was dyno'd and never even came close to leaning out

The only issue here is IDC, it is commonly said that our injectors run the risk of failing and going static at such high IDC rates, but I have yet to see anyone break anything with this set-up.

The same cannot however be said of the 2.5" 60# combination, which seems to claim piston #4 at will.

So, keep that in mind and make your own decision. If you can afford it, 60# injectors and a custom tune is the way to go, as it will give you room to go smaller than 2.8 in the future, but several members have had luck just slapping the 2.8 on stg 2. I guess the choice is up to you.

 

Have had my Stage 2 and 2.8 on for 7 months, not one problem and never a CEL!

 

I am curious to know also, because we are haven't made up our minds yet on wether to use a 2.8 or a 2.9 with the 42.5lb injectors and the stage 1 tune (which is the same as stage 2). Like everyone is saying about IDC's i totally know where they are coming from. It really is not good to have an injector go static. I think everything has a factor in it. Like regular driving conditions, and altitude. I too am just curious to see how many people actually ran a 2.8 with 42.5lbers and a stage 1 or 2 tune and actually had a problem. Not that they just took it off to play it safe. Not that playing it safe is a bad thing, i'm just curious to know who actually had a problem arise.

-$aldi

 

^^x2...I want to go to a ZZP 2.8 ZZP says it will work with the stage 2 setup and tune. So does CA with their 2.79

 

The ZZP is the one that we were going to use but we were hearing rumors about people shouldn't run a 2.8 because of "blah blah blah". I'm just curious to see if it was a rumor or if someone actually had a real problem.

 

i took my 2.8 off last night.
there is a reason.

it was fine till about 6500 rpms, then the a/f spiked lean really hard. was runnin 11.0 then at 6500 would jump to 12.2. shut it down right away. before it was runnin 10.7 all the way to 7k. the injectors gm use are weak. do not do it unless you have a way to monitor it closely.

 

ya me too, im in the same loop whole...i'm still deciding to do 42's or 60's since 60's will give me more room to move around in the future but i only have a 2.9...i wana be safe then sorry....would 60's and 2.9 even work or should i stick with 42's and 2.9 if i dont decide to move around later on??

 

i have been thinking about 2.79 but not untill i buy my wideband

 

I have been running the 2.79 and my GM stage tune for a while with no negative repercussions.

I went to the now out of business VT racing for dyno time at 3 different times.

once stock

once with stage 2

once with my stage 2.79 (as I call it)


all in all it ran very rich with stage 2 on it. When I slapped the 2.79 on it leaned it out a bit.

when I look at my dyno charts right now to me it looks like the tune is attempting to balance the a/f in stages. it starts a little lean then adjust, finds that it is still lean then adjust a third time where it ends up a bit on the rich side.

 

where can I get a 2.9 and for how much?

 

the injectors GM uses are weak?


could you explain that better?

I think maybe you mean....they are weak when you use them at 120%+ of their intended useage....

 

when i logged the stage 2 with the 3 incher on it, it was 117%

i got the 2.8 setup down to 105%. it would not hold it, no matter what i did. it's fine till about 6500. then IDC spikes big time.

it would hold 11.0 all the way up to 7k. then last night it just wigged out, the injectors finally gave up, couldn't do it anymore. it lived happy for two weeks. with 50 lb injectors it would be great. that and it just got way too hot on the iat2 side of things.

 

and did you realise that HP tuners doesnt log our IDC properly without altering some of the variables?

You honestly think GM would sell a kit and warranty it, right from GM performance devision.....with 117% IDC?

 

I am running a 2.85 the perfect balance between too much and to little!

 

That is a hard question to answer when cobalts only been out for nearly 3 years.

 

well i saw something about the GM stage 2 tune. that depends on what year you're talking about.

the 07's have a much richer tune from GM on stage 2 (and stock for that matter!). It's probably why the one guy said he was running 117% IDC on stage 2 tune. It's just crazy. I'm planning on going 2.80 and 42's. There are around 6-8 cobalts on CIAZ.net that run that setup here in AZ and i've never seen anyone with a problem.

with GM's tune at 117% dutie cycle on Stage 2, i bet you'd still run rich if you put the 2.8" with the stage 2 tune and no reflash, but i still wouldn't recommend it. if you do the 2.8" get a retune, you'll need it.

 

trust me, im not new at this.

im going to find out the exact IDC tomorrow {saturday} if everything is cool. the 2.8 goes back on. the bad thing is, i have the 3.0 pulley pulling just as hard right now, if not better up top.

again, it also could be the wideband im using freaking out. which will be double checked tomorrow.

as far as the duty cycle. im using the config file that denny uses on this hp tuners logger as well. it could very well be wrong. i don't think anyone has taken the time to stick a tech2 on the car to see how gm reads things.
but we are about to find out!

 

I'm running the 2.8 setup for a year now and no problems, but you're starting to scare me now with the IDC thing