How much boost can I run with 60lb injectors and stock bottom end. - Boost Forum

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How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 8:18 AM
I have a cobalt SS supercharger on my 2003 2.2L Ecotec Cavalier, and I want to step the boost up to 17psi. The car will be professionally tuned with 60lb. injectors, just wondering if that is ok for the stock bottom end.

Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 8:23 AM
If you are having it tuned at a dyno, keep an eye on the whp - if you get much above 275-300, it probably won't last long, even with a good tune. I'm not sure at what psi your set up will make that kind of power, but 17 psi is pretty high for an M62...



Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 8:33 AM
15 psi and it'll pop.



Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 10:06 AM
I see alot of guys with the 2.7 pulley and they are making like 250 whp. Thats like something I am looking for. But im not sure if my bottom end will hold. I was going to take it to a hi-po shop right down the street who said they could tune it. Not to mention I have a stock automatic tranny. I dont think there will be any issues with the tranny because its not going to have to deal with any kind of lag from a supercharger like you would get with a turbo. But i dont want to put this smaller pulley and fat injectors if my bottom will give.
Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 10:07 AM
What kind of injectors are you running with your s/c cavi and what makes it pop?
Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 10:38 AM
I was running the 36lb supercharger kit injectors GM provides with the kit. What makes it pop? Your rods won't be able to handle 250+ horsepower reliably. Plus, at ~15psi valves start to float, you start knocking, and then a rod snaps.

Also, with that small of a pulley, you're going to have serious iat heat issues. Sure, you'll have the boost pressure, but your iats will be well over 250 degrees. You need to cool those down.

On a stock bottom end car like yours pushing the kind of power you want, be prepared to do a rebuild.



Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 10:39 AM
How are they going to "TUNE" it. The gm supercharger reflash is locked on the ecotecs so they can not modify it with HP tuners however they could flash your computer to a stock tune and then modify that. Or was the idea for them to just slap an fmu on there?



FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 12:24 PM
I actually havent had it taken to the dealer yet. I havent even finished it yet, im at the point of getting new injectors and wanting to put the pulley of choice on there...and then taking it to the shop to get tuned so they would be flashing a stock computer because I havent had it tuned yet.
Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 12:24 PM
so then is the most boost you can run 14? using like 42lb injectors?
Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 1:14 PM
If I were you I would just run the 3.0 pulley, that is the safest bet on stock internals with the gm reflash. I have been running that pulley for over 9 months now and have had no issues, and I know of others that have the same setup and have not run into any problems. I would suggest having a heat exchanger hooked up as well though.




Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 2:32 PM
what kind of boost are you pulling with the 3.0 pulley

Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 4:56 PM
What fuel do you plan on using? You can get enough fuel in there with the 60's but you will be seeing quite a bit of knock and have to reduce timing quite significanly to reduce the knock therefore reducing power. Keep it under 15psi and tune it and you will be satisfied w/ the results especially considering you've still got a stock bottom end. Would hate to see the "I blew my engine post." Maximum boost on 10:1 compression w/ 93 octane fuel is 14.5 psi. I've seen this proven quite a few times, w/ my car and w/ another turbo eco. Up to 14psi no knock just had to keep adding more fuel to accomodate the increase in air, but once we went over the 15psi mark, the knocks got to a point where we had to start reducing timing and the car actually felt a little more "sluggish" due to the decrease of timing. If you run a higher octane fuel that is not as predisposed to detonation then running past the 14.5 psi boost level won't be a problem because the fuel will be more resistant to compression detonation.


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Re: How much boost can I run with 60lb injectors and stock bottom end.
Friday, December 14, 2007 5:11 PM
I want to run 93. I would rather run 42's and take everyone's advice about only 14psi because everyone tells me that and I heard that once before coming on here and asking everyone. Im a little concerned about my automatic trans though
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