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2018 GT with Roush 2650. Adjusting boost limiter?

Cjbebens

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I bought a used car that had the above setup. Is there a way to set boost limits easily? I would imagine I have to somehow get into custom tuning the car, but I really don't know much about tuneing. I know the basics about how superchargers work, what mixuture and timing has to do to avoid detonation at high boost, etc. I just want to bulletproof this engine somewhat by limiting boost and I know the roush has a type of bypass, it would just be cool if there was a manual adjustment to limit it to say 9 PSI. Would a larger supercharger pulley be the way to go, like a griptec 3.2 inch or something? Current pulley I measured to 83mm OVER the belt.

Basically I love the car and its running well, but I never use anywhere close to full power, so why not limit it so my 92 octane costco gas doesn't blow it up?
Here are some pics

Thanks everyone!

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engineermike

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In your situation I think I’d install a larger pulley. There are a dozen ways to handle this in the tune though, even torque max by drive mode is possible.
 
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Cjbebens

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Cool, thanks for the reply. It looks like in this case the simple solution will be pretty cheap too. I'll install the new pulley and save tuneing for later. It looks like 3.2 inches is the largest pulley they sell. Based on my current pulley, would that be a decent drop in boost?
 

engineermike

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Looks like the supplied pulley is 80 mm or 3.15”. Dropping to 3.2 would make hardly any difference. I think I’d be shooting for 3.4-3.5 in your situation.
 

jon.smith76063

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Adding a larger pulley seems counterintuitive to me. Why would you want to take available power off the table? You're not going to blow it up by running 92 octane. The s550 computers are able to compensate for the slightly lower octane. 91 is all the western part of the US can get so the stock Roush tune is able to handle it successfully. The biggest killer on the Gen 3 Roush superchargers is heat soak. I would work at getting that worked out before taking power off the table.

The first thing I would do is figure out if you have the phase 2 upgrade or not.
 

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Cjbebens

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Intersesting. I'll look into larger pulleys.
 
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Cjbebens

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Adding a larger pulley seems counterintuitive to me. Why would you want to take available power off the table? You're not going to blow it up by running 92 octane. The s550 computers are able to compensate for the slightly lower octane. 91 is all the western part of the US can get so the stock Roush tune is able to handle it successfully. The biggest killer on the Gen 3 Roush superchargers is heat soak. I would work at getting that worked out before taking power off the table.

The first thing I would do is figure out if you have the phase 2 upgrade or not.
And look into the heat soak issues. Thanks Jon.
 

Cory S

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Measuring the top side of the belt isn’t accurate. By mechanical function, the bottom of the valleys give the correct pulley diameter.
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