Hey Guys, I talked with ZZP about 60lbs Fuel Injectors will have hunting idles and they said that I need Boost Reference Fuel Pressure System in order to get it idle perfectly. I asked them which options that I should get options 1 (Don't need tune) or 2 (Need to be tune)? They haven't get that back to me yet. They said I can run it without them but in time I will have idle surge cause too much pressure to handle. They said Boost Reference Fuel Pressure System will help to handle that and put fuel back in the tank when it's not needed. As far as I know that Cobalt don't have return fuel systems and I don't know why. I need your opinions and your experience with 60lbs Fuel Injectors ?

 

What are your mods?

 

I have the bouncy idle with 60s as well. We don't have a return fuel system but with ZZP bfrps u can get a return style

 

I have 42lbs right now on 2.9 pulley but will switch out to 60lbs Fuel Injectors with 2.9 pulley to free up and get more horsepower out from 2.9 pulley. I am staying on 2.9 pulley cause of heat soak, I don't mind 2.8 pulley but don't want it. I have all the cooling mods on my car already, Phenolic Spacer, Option B Tank with Dual Pass, ZZP S3 HE. I have ZZP 3" CAI, BadMab Header, ZZP 3" Catted DP with 2.5 exit, ZZP 3 Chambered Exhaust. I talked with ZZP about 60lbs idles issues that is what I am concern about and they said get Boost Reference Fuel Pressure System but didn't say which options that I should be getting. To help maintain my Fuel Pressure for my 60lbs Fuel Injectors. Option 1 or 2 ?

 

if ur gonna do it y not just hook up a return system while ur at it? i'm gonna get it eventually just have other things i'm workin on in the mean time. just do it right and hook everything up at once. you'll wish u had in the long run

 

do you have a zzp tune in the car? i found with the zzp tune i had i was getting a rolling idle. having hp tuners, i had a look and they did something funky with their idle overspeed/underspeed timing tables. i put them back to stock, problem solved.

zzp seems hell bent that 60lb injectors are too big for these cars. my car runs fine with 60s, once i ditch their tune and did it myself.

 

i'm waiting to tune my car as well to get rid of idle bounce

 

I am planning to get ZZP tune my PCM but after what I am seeing what you guys said. I am better off to have local tuner to tune my car. The thing is I wanted to know if I get complete Boost Reference Fuel Pressure System with return style Fuel System do I HAVE TO get retune right away when I do all the Fuel Systems ? That is what I want to know.

 

Is Steve is gonna tune your car you will have a perfect idle like me

 

I have 60s and have 0 issues with idle

 

its da tune

 

So, I don't need it do I ?

 

Just because you go to 60's that doesnt mean you "free up" HP. If your IDC is still under 95ish% then why get 60's and waste your money if you are not going to drop pulleys? You are going to net the same power with 42s or 60s on the same setup....

With 60s and a decent tune the idle should not hunt. The over/under speed thing that someone was talking about actually should cure the idle hunt, but I have seen some cars dont like it. Only thing you may hear is some popping here and there but thats not all the time.

 

Yeah, But I want to use 60lbs in a long run if I want to pulley down or change my supercharger to TVS! That is my goal.

 

Just wait until you want to pulley down or TVS. Get the tune all in one so you dont get a charge for a retune. Or that tuner is no longer around and have to pay for a new one.

 

From I heard 42lbs are maxing out with 2.9 pulley. And I rather be putting 60lbs to be safe than sorry. I don't mind paying about 50 dollars extra for to get it retune. When I get my TVS, I will go to local tuner and tune the BEAST out of my car.

 

Look in this link and here is why that I am changing my 42lbs to 60lbs. That guy is on 3.0 pulley with 42lbs. Here is the link.
https://www.cobaltss.net/forums/2-0l...01/index4.html

 

Its in the tune I am guessing or something is up with the PID. There is no way at 12.69 the car is at 120% on a 3.0.... I have tuned a lot of cars and have not seen that. When I had my 2.8 on 42's I was at like 103 at 7k RPM. I would understand that if he was at like 9 afr.

 

Keep in mind that we all live in a different climate. Every State has a different climate that's why different ways of tune.

 

I know. I tune people all over. His should be around the same of what mine would have been, his elevation is close to mine.

 

Also, from what I know the smaller pulley you go on 42lbs is control by boost limiter. Cause 42lbs can't spray more fuel to get max boost if it does then I will be risking to run lean. 60lbs can get enough fuel to get it to max boost. That's why I want to remove boost limiter to get max boost and 60lbs can handle that.

 

Yes he is! Once everything else is in order

 

From my experience you can run 2.9 with 42's, 2.8 is where you see the issue. I have never had to limit the boost up top for a 2.9 pulley. If you are on GMS2 tune with your 42s now, there is no boost limits on for top end or low for that matter. I am pretty sure the tune is setup for 100%down low and 200% up top... Which means its all 100%, max, boost.

 

i thought the boost ref regulator is really so u can run a smaller injector. then raise pressure in boost thus increasing flow. So really ud want the regulator and SMALLER injectors instead of the 60. Which would cure the idle hunt but i think u can get it running with a legit tune and no mail order.

I have a zzp tune and it hunts like a mother. i am getting it dialed in, hopefully in a couple weeks. So we will see it disappear i believe. I am running a 2.8/60s/meth.

 

It helps injectors produce more flow depending on base FP and also helps larger injectors overcome possible crappy idle when lowering the base FP.