87 octane?

SRT-4 is premium, and still runs shitty on our cheap 91 octane gas.

Wow i thought it would run on premium.

87camaroPA said:

Wow i thought it would run on premium.

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As did I, makes me wonder how far one could turn up the PSI running it on premium, and if it would push it past the SRT4 in power terms, whats the stock PSI ratios on both cars?

SRT-4 stock is usually 11-13 psi, the computer controls boost according to the outside temperature. The cobalt SS is at 12 psi, but you can't compare them in that way, because an SRT-4 with a 50 trim turbo running 10 psi pulled on a stock SRT-4.

Plus with the high compression of the Cobalt SS, I don't know if you can turn it up to much without having to replace the pistons at least.

Pablo said:

Plus with the high compression of the Cobalt SS, I don't know if you can turn it up to much without having to replace the pistons at least.

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Nevermind, chevy has contradicting information, some say 87, others say 91.

Pablo said:

Plus with the high compression of the Cobalt SS, I don't know if you can turn it up to much without having to replace the pistons at least.

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What is the compression ratio on the SS?

Jay

nuked said:

What is the compression ratio on the SS?

Jay

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It's 9.5:1 on the SS.

Pablo said:

It's 9.5:1 on the SS.

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Hmm, that is pretty high for FI. Hell, that is run of the mill for a N/A 4 cyl. Are the pistons forged?

Jay

nuked said:

Hmm, that is pretty high for FI. Hell, that is run of the mill for a N/A 4 cyl. Are the pistons forged?

Jay

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They are "heavy duty" It does have a forged crank.

SRT-4 is also a boost happy motor as some guys have done 21psi on stock turbo. A local did 305whp on stock turbo with supporting exhaust mods and stage 2.

I would love to see what the cobalt/redlines put out with more boost. Even an added turbocharger with about 18psi(9.5:1 compression here) they would do great!

I think the cobalts need lower compression, so they can run more boost, or they gonna have problems with head gaskets and stuff.

I'm wondering if thew guys raising their boost over at redlineforums.com are using 87 octane or premium?

makes me wonder since sometimes people juat get into the boosted scene without knowing the ill effects of raising boost vs fast burning fuels

My WRX runs on premium, gay

I own an ION Red Line and use nothing but premium, it is what is recomended for the engine but the manual says you can get away with a mid grade octane. I also live in an area that has reformulated gas with 10% ethenol, but the boarder of the county west of where I live is not far away and they do not have reformulated gas so I try to fill up with non-reformulated gas as much as possible. I have read some bad things about injector problems from the reformulated gas. Enjoy those Cobalts when you get them, I am having a great time with my Red Line.