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jsalbre

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Yeah for sure. I actually have some feelers out to see if this controler has a message or input that could be used to trigger a tow mode. The auto stuff is just not as consistent as I would like it to be. I want to be able to select a shift patern and have it there at all times when needed. Wonder if the tazer guy could create this message and try it out?
Ok, we’re definitely on the same page here. I made some attempts with AlfaOBD using settings that people in the Challenger forums had used for enabling a sport mode button in the “Controls” page of the infotainment system on their cars, but had no luck.
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jsalbre

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on NA, the internals are (usually) over built for the power application from the factory with reliability in mind, whereas in this case we are applying power and load figures that were not factored into the design of the motor. The same thought process would apply if you were ramping up a larger NA motor.
I was referring specifically to the instant on of a roots vs centrifugal. There’s no denying that FI puts more stress on a system than NA, but I don’t see why that stress coming on at a higher RPM would make any difference. It’s not like the engine is more durable at higher speeds.
 

dakota.morgan91

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I was referring specifically to the instant on of a roots vs centrifugal. There’s no denying that FI puts more stress on a system than NA, but I don’t see why that stress coming on at a higher RPM would make any difference. It’s not like the engine is more durable at higher speeds.
I gotcha, I dont know specifically how hard the shock difference is between the two charger types, but I do know from the Subaru world that if you turned up the WRX, you have to be easy on the transmission... instant power shock to the transmission can break parts, but smoothly putting the power on would keep everything reliable..... I am assuming we are referencing shock here and not stress from just power.... This is partially because every mechanical part (bearings included) have SOME sort of play, flex, deflection etc.... The dead space as you transition from no-load to loaded is what causes the "shock" to parts... if you come through that moment slower then lay the power on parts will last longer. It is the same idea as if you put your fist against something and push with a specific force or have your fist just above the surface then apply the forward push.... only one of those scenarios would hurt your knuckles even though you are applying the same force.

I hope this helps! I love nerding out LMAO
 

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Why is the instant-on boost any harder on internals than a NA motor of a similar power level?
on NA, the internals are (usually) over built for the power application from the factory with reliability in mind, whereas in this case we are applying power and load figures that were not factored into the design of the motor. The same thought process would apply if you were ramping up a larger NA motor.
It's all about shock loading. Think about a tow strap. It can hold maybe 30,000 lbs. of force before snapping. But if you yank it really hard and fast and snap it, you can break it at maybe only 15,000 lbs.

The power coming on more gradually saves the engine if you really crank up the boost.

By the way, there are no N/A 3.6L engines that make 450 HP. At least not that I'm aware of. Throwing a blower onto the P-star engines in the Jeeps takes them well beyond design capacity.
 

DAVECS1

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The 2014 and up was designed for production of 420hp. Has forged (small) rods. Pistons are cast, but if you are not detonating then they will live. The rings are high, quality but low friction (thin). Has nodular iron crank with 6 bolt mains and iron cylinder liners.

The transmission, even the light duty one is really built to take a beating. Even if the parts are not built it has really good torque management strategies. If it is tuned well I would have no concerns laying down 450 ftlbs.

https://www.pentastars.com/engines/tech.php
 

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WXman

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The 2014 and up was designed for production of 420hp. Has forged (small) rods. Pistons are cast, but if you are not detonating then they will live. The rings are high, quality but low friction (thin). Has nodular iron crank with 6 bolt mains and iron cylinder liners.

The transmission, even the light duty one is really built to take a beating. Even if the parts are not built it has really good torque management strategies. If it is tuned well I would have no concerns laying down 450 ftlbs.

https://www.pentastars.com/engines/tech.php
Right, but as I recall that was regarding a forced induction version of the P-star that was planned originally but then scrapped later. The N/A 3.6 that we got in the States was built much lighter duty, with different rods, heads, and other parts. It's even an open deck design. It isn't really built with high amounts of power in mind. A strengthened and reinforced P-star with a factory turbo would have been cool, but it didn't happen. At least not here.

Pushing a blower on a Jeep very far would make me nervous. Just saying. I know a lot of guys have done it. But I haven't seen any of them with high mileage yet.
 

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The current P-star is built with the stuff I listed. I have had my hands on the internals, they are not race car stuff, but they ain't bad and I am not nervous. I have 21k on mine with good tuning and absolutely no issues. Even with lots of towing and hauling. I have put forced induction on more fragile engines than this.
 

jsalbre

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I gotcha, I dont know specifically how hard the shock difference is between the two charger types, but I do know from the Subaru world that if you turned up the WRX, you have to be easy on the transmission... instant power shock to the transmission can break parts, but smoothly putting the power on would keep everything reliable..... I am assuming we are referencing shock here and not stress from just power.... This is partially because every mechanical part (bearings included) have SOME sort of play, flex, deflection etc.... The dead space as you transition from no-load to loaded is what causes the "shock" to parts... if you come through that moment slower then lay the power on parts will last longer. It is the same idea as if you put your fist against something and push with a specific force or have your fist just above the surface then apply the forward push.... only one of those scenarios would hurt your knuckles even though you are applying the same force.

I hope this helps! I love nerding out LMAO
It's all about shock loading. Think about a tow strap. It can hold maybe 30,000 lbs. of force before snapping. But if you yank it really hard and fast and snap it, you can break it at maybe only 15,000 lbs.

The power coming on more gradually saves the engine if you really crank up the boost.

By the way, there are no N/A 3.6L engines that make 450 HP. At least not that I'm aware of. Throwing a blower onto the P-star engines in the Jeeps takes them well beyond design capacity.
I’m familiar with shock loading and the related (potential) consequences, I’m just not sure how that applies to the roots blowers. It’s not as though it’s an on/off switch, the boost and power are still ramping up, just on a steeper curve.

In fact I’ve seen more damage to drivetrains due to boost lag, though that’s mostly been turbocharged offroaders. The driver gives some gas to get over an obstacle on a climb, then gives a bit more because it didn’t feel like enough, the boost kicks in, the vehicle gets to bouncing and you pop a diff or u-joint. This can definitely be mediated with experience and finesse of course.
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