Just a little information that I have received from ZZP:
This list is the proper order of how to mod your cobalt:

ECOTEC build up

Stage 1

3.1 - stock car with raised rev limiter, 3.0 can be run with stock shift points

Stage 2

2.85 – 42# Injectors/ Inj Harness/ 1 step colder plugs/ PCM1

Stage 3

2.7 - 42# Injectors/ Inj Harness/ 2 step colder plugs/ PCM2/ Header/ Downpipe, aftermarket clutch required

Stage 4

2.6 - 42# Injectors/ Inj Harness/ 2 step colder plugs/ PCM2/ Header/ Downpipe/ 3”Catback, aftermarket clutch required

Stage 5

2.6 with overdrive balancer – 65# injectors, all exhaust mods, aftermarket cams, aftermarket clutch required


You cannot run a pulley without the supporting mods listed above, without the supported mods the chance of damage to the engine is very high. The smaller the pulley the more air the blower will move (more power), but the easier that you can get air in and out of the engine the less “boost” you will see on a boost gauge. Boost is a measure of resistance of airflow flowing through your engine. For example you could run a 3.0 pulley on a stock car and see 15 psi of boost, then install a header and downpipe and the boost would decrease to 12 psi but pick up 20+whp.

Many people make the mistake of thinking that dropping pulley size and adding boost will always make more power, it won’t. If you have too small of a pulley for the supporting mods, the boost will be very high and it will require more HP to drive the blower than that power you’ll make from the extra air. As a general rule, 17 psi or so seems to be the maximum efficient level of the M62 blower. If you have more than 17psi, the blower is out of its efficiency range and not making anymore power. If you are already at 17psi, then you’ll need more supporting mods before dropping in pulley size.

The smaller belt from GM works well for taking up the slack when running smaller pulleys but it doesn’t give you any extra tension. The ZZP adjustable tensioner increases tension and is recommended to maximize performance of 2.85” pulleys and smaller. We do not recommend pulleys smaller than 2.6” in any circumstance because the belt wrap is too small and you’ll get belt slip, which will cause erratic boost and high levels of belt wear.

-K&N filter or CAI is always recommended

-The stock clutch is capable of holding around 250WHP. Once you are around a 2.85 or smaller pulley the stock clutch will have a limited life.

-Engine/Trans mounts are always recommended to cut down on wheel hop, but they do increase the feel of vibration from the engine.

-Adjustable tensioner and/or the smaller GM belt is recommend for pulley sizes smaller than 3.0

-None of our Modular pulleys need to have the snout machine

Hope this helps,

Turbo Tim
ZZPerformance.com

 

i beleve all that list except for a few "issues" i see in it......

for one at the end on there "stage 5" they say you need cams...BULLSHIT!

grainted our stockers arnt the best for the higher revs we are runing or the huge amount of extra air were craming into the motor but theres no need to do cams unles you want to do or to move the power band around.

also they clame that anything smaller then a 2.6 is a bad idea to do less belt wrap...
a larger idler pully INCREASE'S the belt wrap so when we drop to a 2.5 its not to far off stock levels.

so the GM stg2 belt PLUS a 76mm idler pully I think will make propler belt wrap and not kill the belt.

 

Nice find. They makes some good points but no cams necassary for a stage 5.

 

The question I have now why is that they say you can use 42's all the down to a 2.6? Everyone else says different/ I know we went over this but finding this makes it so confusing now. All I want to know is what set up will be fine on a 2.6 or 2.7?

 

They're doing way more than just pumping more boost into the motor. They're cooling down the spark with those plugs, with the CAI and 3" exhuast you're not neccessarly boosting as high because you've given the exhuast somewhere to go. But still IDC's don't lie. Everything trusted members have posted so far points to the IDC's being too steep for 42# injectors.

 

alrite i'm assueming you have the GM stage kit do to your sig......

with the 7k red line and a 2.7/2.6 the 42's WILL NOT be enough fuel.

all the reasons have been exsplaned in other posts.

 

this just took a very interesting turn. from the looks it would appear that a 2.8 gmstage 2 is not only safe but adding support mods ie intake exhaust should be fine. hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

edit: we still need more information however, and I would agree that previous to this latest update the information provided points in the oposite direction of a favorable outcome

 

Agreed. How risky do you think a 2.8 is?

 

some people run it and still have a rich run and others do it and have a lean run. it seems to be random yet for all the info provided there doesn't seem to be any solid information for or against the mod

 

silly question, wats pcm1 and 2

 

I guess a tune? I didn't think ZZP did PCM tunes.

 

I don't think they are saying you need cams. To me it seemed like that's what their Stage 5 kit will include. Remember, they have a 04 Red Line that they are using to develop parts for the LSJ.

 

Would you need to tune the engine if you run the GMP Stage 2 and the 2.79" pulley from the cobalt addiction website?

 

that is what the thread is trying to prove or disprove. so far nothing stands out but I am sure more will contribute to put this one to rest

 

HOLY CHRIST!!!!

has nobody read my posts this whole dam time?

i gave specific examples and exceptions but heres a dumb as I can make my answer...

IN ORDER TO RUN ANYTHING SMALLER THEN A 2.9/2.8 SAFE YOU HAVE TO TUNE THE ENGINE!

becasue you would have to jump out from the gm 42's wich you can use with a stage tune into the 60's that requie a custom or Intence tune.

 

so your information is the end all of any information on earth thus anyone running rich could not possibly be doing so because your information says so? so far each thing against it has been countered by something for it so the argument is still up for contributions with new information

 

Its not simply an argument its pure fact....

42.5lb/hr injecters do not flow enough fuel to run a 2.8 or smaller safely at 7k rpm.

can it be done yes...is it smart NO....

i am a prime example of this due to the fact that i ran that set up with a 2.7 and i've loged my IDC's multiple times...all of them were WAYYYY over the safe 80% IDC mark around the 6400 rpm...and over the static cut off of 92% IDC by 6600ish rpm....and i even saw 115%-120%IDC's tward 7400.

no argument about it...just fact.

please remember that just becasue something isnt "maxed" out before 100% an injecter goes static arounfd the 90% IDC...thats where it just stays open and dumps fuel with no control.

 

anyone try to bump the FP up? what is our current FP running at? anyone gauge it? I know my reg ecoted goes from 44 at idle to 55-56 at WOT....

 

OK so you had a 2.7" pulley and were at 92% IDC by 6,600rpm. So the safe thing to do is run a 2.8" pulley and make the redline 6,600rpm. That should be OK. Or even 6,700rpm.

 

sorry to jack the thread but what is hp and torq diff from 2.7 and a 2.6 cant decide which one to get any suggestions?

 

After reading this 9 page thread I'm just wondering where your getting you duty cycles from ? Are you using HPt's duty cycle gauge ? I just had a 2.7 and lucas 42's on the dyno a/f where in the mid 11's thought the pull and IDC was 84% . BTW when did the 80% become a rule the Intake valve isn't open 80% of the time ? I'm just looking for some clarification as you seem to know what your talking about .

 

my IDC rates were taken from multiple HPTuners logs...and on the GM 42's with a BilletFlow 2.7 and a custom tune my IDC's were in the 118%-120% IDC rate.

also i never talked or refured to an intake valve like you said in your post so i'm a little confused by that....but heres what i think you were talking about.

80% Injecter Duty Cycle(IDC) is as high as you want to push if you can avoid higher becase you can be 100% sure that the injecter has full fuel control.

in the high 80's and def in to the 90% and up the injecter often goes staic where it just dumps fuel with no control and that can and normaly does lead to a lean condishion.

your IDC's with the Lucas injecter will act the same way UNLESS they are rated at the 42.5lb/hr flow rate at a lower fuel pressures.....

our fuel system runs at the 60psi mark so the famious "60's"...the 60lb/hr injecters everybody use's are truly 70lb/hr becase there rated at 60lb/hr at a lower fuel pressure but sence our operationg system wont go above 64lb/hr we have to call then 60's even tho there is more flow to be had but a totaly differant OS is needed.

 

very little...the issue in our world is that some people mesure there pullys at differant places on the groves...the top or bottom or a few other ways....so a 2.6 and a 2.7 might be closer to each other then that...or there may be a bigger differance.

but as it stands with a .1 differance there VERY little differance....

 

The other thing to keep in mind is that you start to gain a greater amount of torque compared to horsepower when you drop below 2.7".

 

with a 2.7 and 42's a 6600-6800rev limit might not be a bad idea.

if you can use HPTuners to log your IDC's and set your rev limit to as high as you can as long as your not over the 90+% IDC for to long....

my 120% IDC dident come in till close to my 7400rpm red line.