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Discussion Starter #1
I'm not the most mechanically inclined so please bare with me. My GTs been PI swapped going on four months. We used a donor engine out of an 03 GT. Almost immediately after the swap, bank 2 senor 1 basically stopped functioning.

I was reading around the other night and saw a post by a guy on Corral claiming that post-PI swap the compression ratio becomes equivalent to that of a Cobra. Is that true? Does that mean I need to start running 91 or higher? I tried looking around but it seems like more guessing than anything else. If they're completely unrelated it'd be nice to know. Thanks in advance!


- Hill
 

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IIRC the Cr does go up into the 10's . Does it ping ? Normally it pretty easy to tell when better gas is needed , Running 91 would'nt hurt anything , Id try a tank of 91 and tank of 89 .
 

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Discussion Starter #3
No pinging that I'm aware of. I've only got a 1/4 of a tank so next fill I'll try 91.

Sent from my cell.
 

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The compression ratio and the O2 failure are completely unrelated. Most likely the O2 sensor either came unplugged, or is just bad.

The compression ratio does get raised on a PI swap, meaning you swapped the PI heads onto the stock NPI block. In your case, you used the entire engine from an 03, so no, your compression ratio didn't get raised and you don't have run premium gas. Also, the Cobras run the same CR as the GTs.
 

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Discussion Starter #5
We had a donor engine but to my knowledge he swapped h/c/i, not whole block.

Sent from my XT907 using.
 

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^ That would put you around 10.4/1 CR.


Just like me. :naughty:
 

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We had a donor engine but to my knowledge he swapped h/c/i, not whole block.

Sent from my XT907 using.

Ah, yeah, then your compression ratio is up. I ran regular in my PI swapped GT and never had any problems, but with the CR above 10.1, there is always the chance of pinging.
 

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Discussion Starter #8
Filled the tank to the top with 89. They didn't have 91. Maybe I'm "crazy" but I can tell a difference for sure.

With the CR up, should I look into getting a tuner/dyno? I was going to pick up an SCT tuner from AM soon. Thanks again for the responses!

Sent from my cell.
 
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