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The only difference between the L61 and the LAP is the LAP has the LE5 VVT head, the blocks are the same specs although gen 1 blocks are 05-06 and gen 2 is 07 and on.
 

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gotcha so ill be good with this one. i just have to figure out that second part about the .040 and so on
 

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Yeah not really sure which thinness to run.

But be sure to pair it with ARP head studs.
 

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so i should get the .040" one?
 

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ha i dont know too much about compression. which one would you recommend?

---------- Post added at 05:18 AM ---------- Previous post was at 05:11 AM ----------

im thinkin .045" since its in the middle, kind of a compromise almost
 

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Boosted cars typically run lower compressions. Makes it safer that way.

If it were my car, I'd take the risk and keep the compression up. More power. After all, isn't that the main idea of an FI build?

You could also shave the block/head while you're there to bump up the compression ratio even more.
 

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yeah im still thinkin about sticking with the middle ground. keep it a little safer too but not taking too much of a risk.
 

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Plain you're on the right track there in a way. Boosted cars typically run lower compression ratios yes, but only from the factory. I can explain it for you guys in a quick and simple way (I can do further explaination in detail off this topic tho if you message me).

Lower Compression Ratio = Less Torque = More Boost that can be achieved "safely" without Knock on lower grade fuels = Lower engine temps

Higher Compression Ratio = More Torque = Less boost needed to make the same power, BUT requires a higher grade fuel to keep from getting knock (to a degree) = Higher engine temps.

Keep in mind tho guys, boost is NOT the measurement of power, boost is the measurement of restriction, so more boost does NOT always mean more power. More boost giving more power is only when you've maximized the flow potential of the engine and it will not flow anymore and you want to add more to it.

Cobaltftw, you can go with the .040 HG, it will bump up your compression by like .03 or something like that. It's not a lot so it's not even something you should fret upon a whole lot. Just make sure you do a good amount of logs to get the tune back in touch with reality. Any slight bump in compression means you really only need to add a little more fuel and possibly take a little timing away at first then you can bump it back up as you log.
 

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oh ok awesome, that definitely makes more sense now lol .040 it is. thanks for the great explanation.
 
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