Is it safe to use the diamond racing pistons with the 10:1 CR, i thought with a FI car you wanted to lower the CR not up it and what else needs to be done after you install them, i.e. colder plugs, etc.???? Thanks for the help.

 

They were used in the 300+hp build articles from GM and they can be used. Read the articles and go from there.

http://www.gmperformancedivision.com.../23/ecotec.pdf
http://www.gmperformancedivision.com...tec_Part_2.pdf
http://www.gmperformancedivision.com...tec_Part_3.pdf
http://www.gmperformancedivision.com...tec_Part_4.pdf

 

Thanks for the help I've been looking for these for a while and havent been able to find them, thanks alot.

 

Your welcome. Glad I could help.

 

Victory Red did you decide to take their 300+ HP build further by including what they did and adding onto stuff that they did or did you build your own engine from scratch cause im seriously thinking in following what you are doing to your engine, not like withing the next week like you but in the next couple years.

 

I started off planning to do the 300+ build. Then when doing the research into parts and asking every question I could think of I thought about where I want to take my engine. I wanted to have the option to do a twincharged setup on the car. This meant either redoing some stuff when the kits were available or just start the build looking at what I want the engine and drive-line components to withstand. That is how I ended up doing this monster build. I will not utilize the full potential of this engine build until I either do the twin charge or throw on a 150 shot of nitrous. Heck I may even put on the twincharged kit and have room still for a smaller shot of nitrous. This will be figured out after this part is done BUT I will already have done everything needed ahead of time so that I will not have to wonder and worry if this next piece is what will cause my engine to fail. I really don't mind spending this kind of money to do it right but I would hate having to do it all over again because I thought "that part is fine, it will hold up no problem. Bang!"
Not for me. I don't gamble on anything so there is no way I want to gamble on my Cobalt\race car\toy. This build will improve and balance my engine as well as build in protection to prevent heat soak. If you really want to do this type of build, invest in the foundation of your engine first so you don't have to re do steps along the way costing you more than you need to spend.
Know what you want, ask every question that you can think of, to all the knowledegable people you can ask and then you can start planning your build. I have done that very thing since I joined this forum and many members here gladly helped me out by answering my questions. Good luck.

 

10:1 is a bit high of CR for a high boosted FI set-up. Do not plan to run much pump gas. Race only or a race mix for those higher boost levels. The lower compression pistons like that of the Supra for example, are 8.5:1. This would be a little too low for the cobalt IMHO. It would turn the car into a low end slug I think....BUT, it would allow for more pump gas on the higher boost levels.

Just make sure also that those pistons have some nice thick rings.

 

I totally disagree but isn't that what this country is about

I envision 2 tunes, one for pump gas and 10:, and 1 for race gas. REAR easy, it's called the caspers timing commander and HPTuners. The GTP's and GN's have been doing it for awhile now.

The 10:1 will help low-end power and be critical in making max power.

 

10:1 is not sky high, but I am stating that you will be able to cram more boost on pump gas at higher boost levels on lower compression. Simple actually.

You can't compare this motor to the GTP or GN. Totally different platforms, build and thresholds.

 

Sorry, i didn't fully explain my analogy The GTP's and GN's thought at one time that lower compression and higher boost was the way to go to make more power. Now there has been a very succesful shift towards high compression w/ boost. This possible thanks to our fine software and port fuel injection that is controllable to individule cylinders.

If you build a lower revving higher torque motor, it will last longer. I don't care whether it's 4cyl, 6cyl, or 8cyl. It's still the same, suck, bang, and blow!

Another way to look at it, if i were to run 10:1 compression, i know could go back to larger pulley and still be at the same TQ and power level. I now have lowered the air inlet temps to the motor and taken some stress off of the blower.
Make sense?