Well yesterday me and my friend that does all the tuning on my car set me up with a new tune yesterday. We did some pulls, and we both about died when we saw the data log, at 5k rpms my idc were at 122%!!!! So as of now iam not going to drive the car that hard, or shift at the 7k redline, the new tune i got is awesome though, i hit a max boost of 19.53lbs. Also with these injectors on the car i still ran a 13.6 @ 104. 60s are on the way.

 

Yea i was suprisded it almost hit 20lbs on the 2.7, its time for some 60s for me.

 

What is your duty cycle with the 42# injectors and 17psi?

 

Its fine your just not gonna make any powerand your injectors loose control over fuel delivery. Before I put my 60's in, I was shifting at 7200 on the 42's. Is it the safest thing in the world, no but your car isnt gonna run out of fuel, just run out of the ability to control the exact amount of fuel. I have a wideband and after about 6200 the car just tries to run as rich as possible by dumping fuel.

 

Yea the injectors are justy giving out all the fuel they have.

 

Hey quick question, what boost controller are you refering to? I assume your referring to an actual controller and not just a function on hp tuners. And where can i get this? I am having serious over-boosting problems.

thanks

 

Bad idea. Injectors go static, get stuck wide open.

Check out this link, should give you the informaiton you are looking for.
https://www.cobaltss.net/forums/front-page-news-17/cobalt-ss-sc-got-boost-part-ii-29367/

 

I run the Intense 42# injectors (not the GM ones), and I have the intense 2.7" pulley. I only see 17psi, and my duty cycle is 91%. I have only run a 14.001 @104.xx, but if I had more traction it could be faster. I wonder why we all see different amounts of boost.

 

Elevation, temperature, humidity, supporting mods, all contribute to the amount of boost. With my 2.6 I usually see between 18 and 19.

I'm surprised at how low your duty cycle is. One of my friends had the GM Stage injectors and the 2.8 and was seeing 128% or something like that...well over 100.

Even so, you're running beyond what is considered safe, 85%. Of course, with the 60# you'd be around 60%, and way underutilizing the injectors.

Too bad no one makes 50# injectors that fit.

 

I still don't get it! Why do have 42# injectors!?!? Its just stupid to run a 2.6 pulley with 42# injectors. I know you use a boost controller, but why not just get a 2.8 pulley!?!?

 

I have the intense injectors also, and saw 122% at 5k, and 19.53lbs.

 

When you know what your talking about and not regurgitating info that you've read online I will be more than happy to talk to you.

 

So from my understanding of the previous posts, a 2.7 pulley w/ 42# injectors is acceptable, but if you wish to go higher then 17psi you'd better switch to 60#. Right?

 

I was boosting 19-20psi without problems but is it acceptable... yes... Recommended... No. If you can afford 60lbers get them but if you cannot just know that your loosing control of your injectors and your high end will loose power because of it. I had it like that for almost 5 months now will PLENTY of 7000+ RPM runs without it leaning out. I now have the 60 lbers and the car is alot more steady rowing through the rpms and I've upped the redline a little more lol

 

I was actually leaning out in the top end, and had some knock, that i now dont have, iam geting some 60s though.

 

Ok "Mr. I drive a Redline, thus know all...". (Im just jacking you off). How do you know what I know anyway? I agree that what you were telling him is un-safe, just in more simple terms. However, I would'nt go telling people that allowing your injectors to go static (staying open longer than the injectors intended timing thus, going static and not able to control fuel flow) is a good idea. Even if the car is still running within safe AFR parameters. Which, I understand you were NOT. saying it was a good idea. (at least for the most part.....notice I too run a 2.7" for the track)

I realize that in relation to your high as hell IDC, that your car was not leaning out. However, for some with 42.5lb injectors and 2.7" or smaller pullies, the car is experiencing knock, and leaning out in the upper rpms. The kid would have to get a wideband to really know what his car is doing. Every car is different, so your paticular experience might not apply to him.
(Mainly because of elevation, temperature, mods. etc). (I only see 15lbs of boost with a 2.9")

Try not to make assumptions about a person until you really know them. I wasn't calling you out on your post, just more or less going along with what you said, and tossing additional info. in there. (at least in this post). I should have stated my concners more clearly. No offense taken, and I hope you don't take any from my post as well.

 

We were using ht tuners, i was seeing some knock, but got rid of it, and leaned out a tad in the upper rpms, but not leaning out to the point of hurting the car.

 

I do not have the GM injectors. People with the GM injectors are maxed out on the 2.79" pulley. That puts you over 100%. Those injectors are junky, and the whole kit is a waste.

I use the Aftermarket 42# injectors, and that is why I run a better duty cycle. There is a big difference in their capabilties.

 

The injectors i was using are not gm injectors either, they are lucas 42.5 lb injectors, at 5k 122% idc, so i would be carefull.

 

I just ordered my 2.7 pulley and already have 60lbers just need to get a good tune.

looks like we'll be in the same boat with tunning. then again my car will be in europe.

 

Yea i need a new tune.

 

Let me know if you get around to a dyno tune or something. My stuff is still sitting on the shelf too.

 

Where are you getting tuned at?

 

Hp tuners.

 

Great, I have the 2.79" pulley on the way to me and I have the GM 42lb injectors. ......


I guess I'll have to let the pulley sit in the box until I get the 60lb injectors...