Rage915

do you have to have the pulley puller in order to swap out the stg 2 pulley for the 2.8? i went to my local speed shops and none of them want to do it unless i get them the pulley puller and the special tool for the bolts on the hub of the supercharger.

RedSSBaltSC

If you already have the stage 2 hub on, then all you need is to take out the four bolts. You don't need a puller.

Rage915

is there a special tool to take off the bolts or can i use a regular screw driver?

RedSSBaltSC

The kit came with a special socket and the dealership probably kept it, so you wouldn't change out the pulley and be able to put it back on without them knowing. I got the pulley boys 2.8" and it bolts right up to the stage 2 hub and you can order new bolts. So, you'll have to try to get them off with a big phillips (maybe), I don't know what would work because I have my socket that came with the kit. I wouldn't pay somebody to do it, it's very simple. Just get a friend to help keep the belt from slipping and make sure you loosen the bolts before you take the belt off (newb mistake I made).

Rage915

i got the 2.8 in pulley installed yesterday and i got to be honest im a little disappointed. when we dynoed the car i gained 3 horse power to the wheels and12 lbs of tourqe. so my numbers read 254.4WHP and 227LB of TQ. i have a injen CAI stage 2 reflash and 3in exhaust. is this right? if not what can i do to correct this problem?

1gmfanatik

12lbs of torque isn't bad for a pulley swap..Not to mention you're running 3" exhaust which is actually hurting your setup. 3" exhaust isn't really recommended until you get into the big mods.

1gmfanatik

And believe it or not..Torque is where its at. Torque is what really gets you moving, and for our cars seems to be the toughest to come by.

TXRLU

The supercharger is going to spin faster, so if anything, you should notice the boost coming on quicker. Did you get the smaller belt for the smaller pulley or did you get an adjustable pulley tensioner to avoid belt slippage? (I had an adjustable one from ZZP and recommend that if you haven't switched to a smaller belt). Smaller pulley should also show more boost on your boost gauge. I'd compare your HP and TQ curve with the stock and 2.8" pulley. I wouldn't expect a lot more HP, but you should see the HP and TQ come on quicker in the RPMs which means you wind up the engine faster. Best way to get that HP would be Rev limiter increase for now since it looks like you've freed up other areas (intake/exhaust). I wonder what HP Tuners would do for these motors if everything could be dialed in with all the bolt ons available and larger fuel injectors.

Rage915

i had the stage 2 kit before going with the 2.79 so i have the smaller belt. the car does feel more responsive but i was going by what people were posting as far as 17.5psi and 10- 15 HP gains thats all. i appreciate everyons input thanks !

TXRLU

http://www.zzperformance.com/cobalt_...ts1.php?id=447 That's what I would've recommended, if only because its adjustable to different pulley sizes. I'd be a little cautious about going smaller than stage II's Pulley with the stock belt, may have some belt slippage. BTW, the best HP numbers come when the Dyno Tech crashes into the rev limiter. Not real good for the engine, but the highest HP numbers come near the rev limiter on the LSJ.

Rage915

i have a smaller belt its not the stock one, but do you think the tensioner will help out?

Edubs

I've never heard of anyone needing a belt smaller than the S2 for a 2.8" pulley. I would have thought someone would bring up belt slippage if that was an issue.

CTCOBALTSSS

Yeah the 2.8" pulley is fine with the stage 2 belt. Anything smaller you want an oversized tensioner.

I don't recomend a 2.8" pulley with 42lb injectors thought. IDC's pass 100% at 6,500rpm is no good.

I run a 2.9" pulley for this reason.

Tomtwtwtw

Yeah, I had very minor slippage with stock belt and a 3.0, but zero slip after putting the S2 belt and 2.8 on.

Rage915

so am i getting belt slippage or are the dyno numbers right?

TooManyCars

Hey Eric, don't forget about our altitude, bro. I think were at 4,300 ft or so. I think we'll be lucky to see 16 psi with the 2.8.

Oscar

TXRLU

Good point, although if the Dyno was done and SAE corrected, then it should correct for altitude if I'm not mistaken. Has anyone had their tune dialed in via HP tuners? Would be interesting to see how well a tuned LSJ can get with the bolt-ons and the Stage II. Worse comes to worse, just do what many people suggest I do, forget the Dyno and just take it to the track and compare your times with other cars and keep track of your times.

Rage915

yea true, whats up oscar havent heard from u in a bit. anything new going on?

TooManyCars

Not sure if the dyno is SAE corrected, though. Not much Eric, all work and no play make Oscar a dull boy. I'm going to the graveyard shift in a week... I love shift work . Might make it out this Sunday to Desert Demonz. Lets see how that 2.8 pulls now.

Oscar

Rage915

yea, well see, tell you the truth im not that confident