Can I add a Sprintex Supercharger without any tuning?

olysan

TJ Enthusiast
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Feb 25, 2020
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Chesterfield, MO
I am adding a Sprintex Supercharger to my 2000 TJ 4.0. I’ll be upgrading to bigger injectors and adding a Snow Methanol injection setup at the same time. I’m wondering if I can just run it on the stock ECU tune or will it require tuning. From everything I’ve read both Split Second and HpTuners can tune this setup and I’ll probably go with HpTuners eventually but for now id like to install it and run the stock ECU and tune.
 
The ECU has certain parameters to meet, air, fuel, timing, etc. Anything you do that doesn't change what the ECU wants to do, the ECU will cancel out. If you add more air with a supercharger, the ECU will cancel out by closing the Throttle Body to let in less air. If you put different Injectors for more fuel, it will feed less fuel to the Injectors.

Provided that the additional air and fuel doesn’t exceed the computer’s programmed ability to mitigate.
 
The ECU has certain parameters to meet, air, fuel, timing, etc. Anything you do that doesn't change what the ECU wants to do, the ECU will cancel out. If you add more air with a supercharger, the ECU will cancel out by closing the Throttle Body to let in less air. If you put different Injectors for more fuel, it will feed less fuel to the Injectors.

This is not accurate at all, sorry.




OP, no, you cannot install a supercharger without tuning. Well, you can, but it's going to grenade.
 
Ok, definitely gonna need to tune it. Leaning towards HPTuners but I’m a little concerned about the learning curve I also believe I’ll need 2 bar MAP which is another learning curve as it requires wiring a pigtail and custom mounting. The Split Second device includes a 2bar MAP.
 
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I am adding a Sprintex Supercharger to my 2000 TJ 4.0. I’ll be upgrading to bigger injectors and adding a Snow Methanol injection setup at the same time. I’m wondering if I can just run it on the stock ECU tune or will it require tuning. From everything I’ve read both Split Second and HpTuners can tune this setup and I’ll probably go with HpTuners eventually but for now id like to install it and run the stock ECU and tune.

You could bolt the supercharger on and run it if you didn't change anything else and didn't go into boost. If you change injectors you must tune the PCM. HP Tuners is the go to for stock PCM tuning on these PCM's
 
The ECU has certain parameters to meet, air, fuel, timing, etc. Anything you do that doesn't change what the ECU wants to do, the ECU will cancel out. If you add more air with a supercharger, the ECU will cancel out by closing the Throttle Body to let in less air. If you put different Injectors for more fuel, it will feed less fuel to the Injectors.

How is the PCM going to change the throttle angle when it is connected to the throttle pedal with a cable?
 
Ok, definitely gonna need to tune it. Leaning towards HPTuners but I’m a little concerned about the learning curve I also believe I’ll need 2 bar MAP which is another learning curve as it requires wiring a pigtail and custom mounting. The Split Second device includes a 2bar MAP.

Yes, to properly tune it with HP Tuners you will need a 2 BAR MAP sensor, and a way to mount it like this:

https://texasjeepproducts.com/produ...-spacer-with-ports-and-2-bar-map-sensor-mount
 
So the part about the throttle body was already corrected. The idea your PCM is working against you to limit power is fundamentally wrong though. The PCM is not designed to nor is capable of measuring power output. It isn't fighting efforts to make power. It sees inputs from coolant temps, MAP, throttle position, IAT, narrow band O2 (only in closed loop) and a bunch of other things and outputs fuel and timing stuff via pre-programmed tables. It does try to adjust stuff to get to the factory parameters for those things, but power is not one of those things. It's too complicated to try to explain in a quick post, but it doesn't see you installed a header and say "Hey! I can flow more air now! I'm going to dumb things down to keep it at 190hp so you can't get to 88mph and accidently go back to 1956. Your welcome." That is preached a lot on this forum by people who don't understand how it works and it's just not true.
 
So the part about the throttle body was already corrected. The idea your PCM is working against you to limit power is fundamentally wrong though. The PCM is not designed to nor is capable of measuring power output. It isn't fighting efforts to make power. It sees inputs from coolant temps, MAP, throttle position, IAT, narrow band O2 (only in closed loop) and a bunch of other things and outputs fuel and timing stuff via pre-programmed tables. It does try to adjust stuff to get to the factory parameters for those things, but power is not one of those things. It's too complicated to try to explain in a quick post, but it doesn't see you installed a header and say "Hey! I can flow more air now! I'm going to dumb things down to keep it at 190hp so you can't get to 88mph and accidently go back to 1956. Your welcome." That is preached a lot on this forum by people who don't understand how it works and it's just not true.

Amen, Brother!

🙂
 
Somehow I keep messing that up. You're quite correct. I'll go back and delete that from my post.

No problem, the TJ doesn't operate that way, but there are drive by wire applications that will reduce the throttle angle if too much power is detected. Usually done as part of a torque management strategy and for transmission functions.