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Discussion Starter · #1 ·
Curious...

I was planning on updating one thing at a time on my minivan. First was all the basic upgrades, such as intercooler, exhaust, boost gauge and controller. So that is done...

Next step is to do the top end w/ new G-head (P+P), new turbo (S60), and ported manifolds. I am about to the installation of this phase, but will not be able to do fuel yet (phase 3 of the project). Right now, I run ~15psi on the mini w/ the mitsubishi turbo stocker and get about 11.5:1 ARF at the leanest. Though I realize that I can slap it all together and kind of find the question, wanted to know before hand...

If I put on the S60 turbo in place of my mitsubishi, will the stock cal and stock fuel system provide the proper fuel at the same boost levels?
 

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Discussion Starter · #3 ·
thats what I thought, since it will be moving more air in general. I just wanted to get an idea before trying :D I figured id turn it down and play with it until I can afford phase 3 of my plan. (Im still new to turbos and was not sure how the ECU responded to certain things)
 

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why would this be true? isnt 15psi of un-intercooled air 15 psi of un-intercooled air? if all you change is the pump why would the air be any denser or cooler?
 

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because adding the intercooler makes the air colder, colder air has more oxygen per volume so you need to add more fuel to the mix.
 

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right but i am explicitly saying that no intercooler gets added. the only thing that changes is the turbo, from a mitsu to the super 60. trying be, why does that change alone make the air more dense and thus the mixture leaner?
 

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Oh sorry. The bigger turbo moves more air more efficiently making the turbo not have to spin as fast to make 15psi. This is two fold. 1st is the compressor efficiency and slower shaft speeds means slightly cooler air coming out of the compressor. Now on the exhaust side because you don't have to spool the turbo as high to make 15psi the wastegate opens sooner and allows less backpressure which all means more airflow through the engine. But I don't think it'll affect the a/f's too much, might run 12:1 instead of 11.5:1.
 
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