What mods would I need to run a 2.9 safely?

I keep finding different anwsers.

Is a 2.9 pully over a stage 2 pully even worth it?

 

I've had a 2.9" on my car with the GMS2 tune for a year and a half with no cooling mods and have had zero issues with it. I just added a h/e a few weeks ago to start preparing for some new stuff

Just remember, you can never have too many cooling mods. If you're at all paranoid about it, just throw a h/e on there.

 

put the 2.9 on, and see if you can find a gm s2 tune with modified fuel tables

 

it's worth it.

Some people will come in and say 42lb/hr injectors are fine, no they're not. Get 60's

I would suggest dual pass in addition to your front mount. Other than that and a tune i'd say you're set.

An exhaust would only help.

 

Thanks. I have a h/e already, so hopefully it will be fine.

I wish I had the money for a tune, if I end up keeping this car.

But arent they alott of money? Dont know anything about them.

 

x2 to basically all of that. I think the GMS2 tune is conservative enough that you wont have to worry about the injectors (42s) going static or anything. I haven't had any issues with mine.

 

How much of a difference did you notice going from the stage 2 pully to a 2.9 ?

 

I had the 2.9" on there from the get-go. I just put the 2.9" in the box and took out the Stage 2 pulley, and the dealership either didn't notice or didn't care.

 

you can get ottp to tune it for like $99 plus shipping i think.

 

Sorry, can you explain more?

What are they shipping?

Actually if someone could explain *t00n* that would be awesome.

What does it actually do?

 

a tune, to put it easily, changes how your car runs (injector duty cycle, AFRs, timing, etc). If you were to upgrade to 60# injectors, you'd have to retune because your computer doesn't know you've installed bigger injectors. If you simply slapped bigger ones on and didn't tune, it'd pulse them as fast as your 42s and run unbelievably rich, or maybe not run at all.

You can also tune just to get the most from your car. Little things like advance timing or more accurately stay within the optimum AFR range.

 

i got a 2.85 pretty much the same as 2.9 and im runnin 130% injector duty, which is bad, its gettin fuel cut at top end, and it ran really lean with the stock st 2 tune with a cai and cat back, so id say get a tune, i did drive it as is for a year, but just now noticed how close to death i was, not too happy about that,,

 

I've got a 2.85 as well, just haven't installed it. Waiting to buy the 60pounders and a ZZP can tune (because I'm a broke ass mother ****** and there's no one around here who does cobalts haha). Not worth blowin up the motor just for a few more hp.

 

has anyone with the 2.9 ever put it on and had the blower lock up?
not trying to thread jack

 

IDC's past 80% are not "good".

You go to 2.9 on GMS2 your IDC's are over 110.

I ran that for the longest though. In order to run a 2.9 "safely" you should go with 60's.

 

leaning out the tune over the gms2 will reduce idc's correct?

 

Yeah, if you tune for the 2.9 on 42's you will reduce your IDC's. but they will still not be at a "safe" operating level.

Like I said, I ran the GMS2 tune with 2.9 FOREVER. And had no issues. Car ran strong as hell too.

Injectors are considered "maxed out" at 80%. My IDC's were 122% at 7300 rpm with GMS2 on 2.9. Just to give you a figure.

 

why would you get your limiter raised and not get tuned? lol

but yeah thats what i was thinking since the s2 tune commands in the tens past 4300 (i think) that leaning

out the tune to say 11.6-11.8 would give the injectors a little more room to breath (or pulse lol) than the s2 tune

 

I was effing around with the car.

I leaned it out to 11.9

My IDC's now are 74% with the TVS, 3.1 pulley and meth. (60's). So they're pretty much as far as they can go.

GM tune commands low 10's. First time I got on it after putting in my AEM WB it pegged at 10.0

 

lmao, what mixture are you runnin?

 

80/20.

Holding 24* of timing on 12.1 AFR.

 

niceee betcha like that lol

 

I do. My axles don't.



Ok, nuff with the thread jacking.

 

what year GM Stage Tune did you have when you pegged a 10.0 AFR?? I know the earlier tunes for the 05's & 06's ran pig rich. When I was running my 07' GM Stage Tune it had a command AFR of 10.8.

 

I just remembered, I have a stage 3 pulley sitting in my room.

Would that be worth it? stage 2 to stage 3 pulley?