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Discussion Starter · #1 ·



This just in for my 2.3 build. These will use the "R" connecting rod and will fit the 2.3 block as an OS2 oversize (81.38mm) They are 9:1 CR and use the factory Mahle/Volvo ringset.
 

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LPT being a key part of that equation, if you want to run pump gas you are limiting yourself on your potential boost range going above a static of 9:1.
That's a fairly dated school of thought.

There are thousands of high output high boost engines with static CR over 9, even 10. Oem and aftermarket alike. Especially those with 4 valve chambers and centralised spark location. With decent EMS, it's not just a matter of dumping fuel, retarding spark, and dropping CR to build a reasonable turbo power plant.
 

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So dated that volvo understood they had to drop the static compression on the high pressure cars right up until today.

What people do with their race motors that aren't daily drivers on the street isn't necessarily good advice to people that aren't planning on sleeving their motors to deal with the higher effective compression ratios that result.

Even the thicker 2.3 sleeves will have their limit so this is a great way to find out where it lies.

Good luck though, I'm sure the OP is aware of the limitations, so its the reason I'm asking what he plans on fueling it with. Its not like he or anyone else has a magic wand he can wave to change the effective compression ratio under full boost to keep it from pre-ignighting premium pump gas.
 

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Discussion Starter · #7 ·
I've already run a 9:1 CR engine in my car and it was the best running engine my car has ever had, but it was a 2.5 and I broke it. I know why it broke and this engine won't suffer the same fate.

It's going to run pump gas.
 
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