What is normal boost at idle. Sometimes mine is at 12, sometimes its at 20. What would vary it? Temp?

Car has 500 Miles on it and it's running great. Just curious as I'm new to forced induction.

 

Oh yes and what is the max boost one of these motors can take. I think stage 2 takes it up to 17 if I read correctly.

 

It should be about 20 in vacuum at idle.

I don't know if you heard about this yet but GM has a fix for sporadic idle. It has been a big issue but it's fixed now. Go to the dealership and have them reflash your computer. The fixes for this problem are in the new program.

 

Thanks man! I just wanted to make sure my boost was ok. The idle in my car is just dandy. I have alot of questions about this car. If you could answer them that would be awesome.

1. What size is the stock pulley?
2. I have been reading alot about the 2.8 which raises redline and 15 hp. My car is completely stock. Would that be a good idea?
3. I read that getting stage 1 is a waste of time and stage 2 would be better. Opinions?
4. How much do the stage kits kill gas mileage?

Thanks in advance!

 

Ok, I just saw your sig. Please tell me you didn't sell the WS6 for the Cobalt.

Also, is the idle fix for regular Cobalts too or just you SS/SC guys?

 

I did sell it. And I hated to do it and I'll tell you why. The thing had 130K and it was starting to fall apart. Being a full time college kid and with a full time job half an hour away, I coudn't keep up with the repairs myself it being my DD. It was a rare car but I sold it to a good guy who is going to take care of it and I'll see her every now and then. I needed something with a warranty, reliable, and good on gas. The cobalt was the answer. I would only get the SS/SC though.

 

Someone needs to spend some time searching the posts on here, but I'll help you out as I'm not a ***** like some.

1. The stock pulley is 3.35"
2. The 2.8" is too much for a stock tune, but would be a great upgrade for GM Stage 2.
3. Get Stage 2 so you can get the smaller belt and pulley along with those injectors and tune. This also gives you the ability to run the bolt on 2.8" pulley ring from Pulleyboys for 17-18 psi of boost/fun. Well worth the money by the way. Start looking for a new clutch too with this power.
4. I've actually seen an increase in gas milage with the stage kits when cruising and driving normally. If you get heavy into boost all the time expect around 20-22mpg, and for cruising 25-33 mpg. It's possible to coax even better gas mileage, but grandma would pass you then.

Good Luck and welcome to the SS.net

 

Your the man. Thank you. The search doesn't seem to work. I'll search for stuff and it seems it's very very broad. Maybe it's just me. Anyways thanks for answering my questions. I guess stage 2 is the way to go right now. more boost is better!

 

1. 3.3"(12.5lbs), you will see that after your car gets worn in, you should only be seeing 10lbs right now
2. When adding a 2.8 pulley(17lbs) you would have to upgrade to 42lb injectors, maf translator, and prob a tensioner to go along with it
3. Def get the stage 2, you get more boost, bigger injectors and you can later add the 2.8 pulleyboys ring, and you get a 7k redline
4. With stage 2 people have been seeing around 30 mpg highway, doesnt really change it that much from what i have read

 

I've gotten a little more gentle on the car as I'm up to about 2k miles and the only time I got above 20mpg is when I'm on the highway for a little bit. Even that only takes me to about 20.8ish. Well maybe I do get on it a lot lol. I'm stuck at about 19.1 mpg right now.

 

gas mileage will improve as its broken in

first 2k or so i avg maybe 20 - 24mpg on a tank..

i am about to break 10k miles (got the car in march) and currently im getting 29.8mpg

 

The variation in the vac pressure at idle is whether you are running your a/c or not. I noticed that one too.

 

Wow. Thank you guys for the info. I have noticed my gas mileage hasn't been "Great" but i guess that explains it. i thought it was me "getting on it" too much.

Another question. For "regular" driving, with you guys with the SS/SC, when do you shift.

I try to shift at 2500 but you guys tell me what you think. I'm curious george and I have alot of quetions!

 

In rush hour (where I spend most of my driving) I shift at around 2000 rpm. Or basically at 10, 20, 30, 40 mph. If I can't have fun, I try to save as much gas as possible for when I can open it up.

DIC had me at 26.8 mpg with about 75% rush hour driving, so I guess I've been doing ok.

 

I am still stock, but I get around 25-26 mpg with A/C commuting and around 29mpg without A/C. I also shift around 2K or 2.5K rmps to keep the fuel usage to a minimum.

 

Check out intense's stage kits, such an awesome inversment. If you are interested in going all the way to a 2.8" pulley get the stage 3 but get the 2.8". And the MAF-T is mainly for the 2005's (still an option but not mandatory) but intense now makes a reprogrammed computer.

GM kits seem really expensive for what they are, and people wait FOREVER for them.

Welcome to the site.

Kate

 

Ok. I'm going to be driving it stock for a while, then when I get enough cash, stage 2 is coming and I would like to do a 2.8 a little later after that. CAI would probably come before stage 2. Most of my driving is highway.

Hopefully before I go stage 2 and 2.8 pulley they will really find out if the 2.8 leans out the injectors between 6500-7000rpm

I seen complaints and then applause. time will tell!

 

I want to keep my warranty. I bought this car FOR the warranty because I was so sick of my last car breaking down and breaking down. Will the intense kits keep the warranty? what if a GM dealer installs the instense kit?

 

Intense kits = Bye Bye warranty
GM kits keep warranty.

The injectors that come with Stage 1 or 2 are perfectly fine for the 2.8" pulley. A 2.7" on the other hand gets a little to lean for my liking up top.

 

I wouldn't want to go too small. 2.8 sounds just right. Its amazing how much I have learned today from this forum. I love it. the v8 world is completely different. But this seems much easier too! both are expensive though, especially cuz of GM. I have found a few stage 2 kits on ebay.

I heard they were on back order, is this true?

 

yah, i wouldnt buy one off of ebay, that site just seems to fishy to me IMO.

 

Ebay shouldn't be too bad...just pay attention to who you're buying from. A lot of the kits that go up there are being sold by actual dealers, not private parties. But yeah...seems like everyone has them on backorder, and yet they get shipped out to random dealers all the time. I have no idea as to the method of their madness.

 

Tom, I don't like your sig quote

Kate

 

Well your car's faster than mine, so I'm allowed to act out.

 

lol, ok then. You going to the track tonight? If so i'll see you there after 9. I've got to get to work now.

Kate