Sorry if this has already been asked, i did a quick search and didn't see anything obvious...

I'm running an 06 SC, only has intake and Ingals TD, i'm saving up for the TVS charger and supporting mods but i really want a little more until then so i was wondering if it would be safe to drop from the stock pulley to a 3.1 without having to do bigger injecters. i'm up here in denver so alt. is over 5k feet...

 

You are not going to pick up that much power with just a pulley swap and at over 5K feet, I would think you would go lean a bit faster than others closer to sea level.

 

air is thinner up here (obiviously) stock i'm only boosting 10 pounds.. on a good day...so thats why i'm wondering....

 

Do not drop the pulley size to a 3.1 unless you are getting the 42# injectors and a tune. Don't risk ruining your ride man ....

 

stock boost should be 12.5 psi....... that's wierd. well if you want a little extra power.... do a full exhaust, that'll jump it up alot

 

Save your money, wait for the TVS...

 

i agree do supporting mods for the tvs, maybe a header downpipe exhaust intake lol lot to choose from

 

My god, just answer the man's question people...

Yes, you can run a 3" pulley on a stock car/tune without a problem. Many people on here, including myself, have done it, some for over a year. You being at higher altitude might make it possible to go even smaller, but I don't have any actual evidence to support that so I can't say. You will be fine on a 3.1" pulley for sure.

 

Yes you can do it. Supporting mods would be better to do though. Get the rest of your car ready to support the TVS.

 

THANK YOU

the only reason i don't want to do any exhaust work yet is because i was told you need to run three inch piping for optimal use of the TVS ... well a three inch on a stock motor SOUNDS LIKE **** IMO

 

piping size is not what makes an exhaust sound shitty. Its the header muffler and resonator used.

 

but if i'm not yet pushing the air through the res. and muffler that it is designed for then it will

 

People say the 3" is too much for stock.. not enough velocity.

 

Exhast theory is a huge debate, its about where the powerband goes, you dont "lose" power from too big of an exhaust, you just shift your powerband higher. In theory, you could go so big that you will be out of the practical rev band, but go bigger now to avoid changing things twice.

 

Thats really a good point to get the exhaust now than later.

Wish i would have done it.

 

so my numbers aren't matching up here... i thought the stock pulley size was a 3.3" pulley (83.8mm)

well on crateenginedepot i looked so see what size the stage 2 pulley was for GMPP and they say that the pulley is a 77.9mm (3.06") down from the stock 79mm (3.11")

so which numbers are wrong and what size is the GMPP stage 2 pulley... the reason i ask is because my roomate has his sitting in a box (he dropped to a 2.8) and i didn't know if i just bought a Hub if i'd be able to just use his old one to drop down to w/o having to do injectors or tune...

 

The stage 2 pulley is 77.9. The stock pulley is bigger than 79mm, I don't know where that came from. It's about 3.35", not 3.11".

Yes, you can put a stage 2 pulley on a stock car with no other mods and be fine. A tune would yield more power, and injectors would allow you to raise the rev limit higher and get more power out of the car (Stage 1 basically), but for now you will get a nice increase in power just with the pulley.

Where are you in Colorado, buddy of mine just moved back up there with a red 07 SS/SC.

 

i am runing a 3.1 right now. i put in the step 1 colder ngk plugs. however when i changed my plugs i was running rich already on my stock ss/sc. i did not receive any codes or anything weird even on my 5th day. i did some WOT test's and it ran purrrfect. just when you change your plugs make sure your running at least a little bit rich. if your already running lean. i would not recommend the smaller pulley until you have a flash re-tune or a dyno set up. but if your running rich, go fer it

oh and with the 3.1 pulley i am now at 16 psi spike around 16.5 untuned. i could be off by a pound. i havent really watched the boost gauge. too busy trying to keep traction from a 2nd gear pull... (need tires)

 

I would personally go with you supporting mods first otherwise your going to be wasting money

 

Longmont... about 30 miles north of denver


is there any way to watch my air fuel mixture more closely without getting a wideband?

 

so you wouldnt reccomend puting a 3" pulley and smaller belt compared to stock on the car if that was all you plan on doing? possibly injectors down the road but not for now?

 

i wouldnt do it man .... for the kind of boost/power levels you will produce with a 3" pulley your idc's will be off the charts, and you may risk damaging your engine .... don't be in a rush to put the pulley on unless you have the proper supporting mods.

 

i'm running a 3.1 zzp modular pulley w/ step 1 colder plugs and stage 2 belt. no issues, no CELS nothing. HOWEVER, when i changed my spark plugs i was already running RICH on factory tune. therefore i proceeded to drop the pulley size. but if your running regular or lean DO NOT do it, you will ***** your motor. plus even if you decide not to listen to us. don't run your car WOT all day everyday. personally i don't think you should put theh 3" on. not worth the risk. but i would check if your running rich or not. when i mean rich i mean RICH

 

new to the whole cobalt thing and just got mine like 2 weeks ago. how would you check if your running rich or w/e

 

when you go to change your spark plugs. 1st of all all the cyl. must be running rich it can't be just 1 & 3 or 2 & 4. ok so when you pull the plug out. put the sparking end up to your nose and take a wiff. if you smell a STRONG odor of gas your running rich. if there is actually fuel residue and its a strong smell at the same time your running really rich. like i changed plugs on my friend balt and he was only running really rich on 1 & 3. (he is staying stock though) but if he would of said he should i put my pulley on? i'd say no. plus if your going down to a 3" you really need 42 injectors... the stockies can handle up to 3.1 according to zzp but they highly recommend getting the 42's from 3.1 to 2.9 pulleys. than of course 60's after that. the only reason i put my pulley on is i had a friend do it because he had the pulley puller and i had the time to actually do it since i'm always busy. also i dont race all over town or nothing, i rarely build boost unless its on a sunday aka the philly meets and i'm bound to race there. but if i were you i'd get the injectors and pcm/dyno tune before putting on the 3" seriously dood. but it is your car and your free to do whatever you want.