Can I install a supercharger on a stock 4.0?

Haroon

Haroon

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Lahore, Punjab, Pakistan
Hi Dear.
Hope all is fine there. i am new user for TJ, I recently bought 2002 TJ. want to know that can i install super charger on a stock 4.0 L engine or i have to replace any engine parts like Pistons or valves.
Furthermore what will be the impact on engine life?
Regards

M. Haroon
 
No. If you run a supercharger with around 6 psi of boost or lower, you do not need to change any of the internal engine parts such as pistons, valves, etc. I've been running a supercharger with 8 psi of boost on my TJ for well over a year without any issue.

The only time you'd need to start changing out engine internals would be if you planned on running much higher than 8 psi of boost.
 
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StG58 said:
6psi doesn't sound like a lot of boost. But remember, you're going from a vacuum in the intake manifold to 6psi of boost. It'll get the job done. Right, @Chris?
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Yep! It sure will.

Just make sure that all your vacuum lines are ABOVE the supercharger at this point. Otherwise you'll be blowing 6 psi of boost into your vacuum lines... not good!
 
Just a precaution I have been told many times a turbo or supercharger on a TJ works fine but if you off-road do not do it as they get red hot and will crack when they hit water or even a splash from puddles. I don't have one so I cannot attest to it but I have seen may pictures of cracked ones from offroad use.

This may only apply to a turbo though I do not know the difference between a supercharger and a turbo.
 
Tj04 said:
Just a precaution I have been told many times a turbo or supercharger on a TJ works fine but if you off-road do not do it as they get red hot and will crack when they hit water or even a splash from puddles. I don't have one so I cannot attest to it but I have seen may pictures of cracked ones from offroad use.

This may only apply to a turbo though I do not know the difference between a supercharger and a turbo.
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I could see how this might be true for a turbo, yes. A supercharger though, not very likely. It all depends on a variety of factors as well with that turbo setup.
 
Makes sense. I also figured the two were the same, judging from your response they are not. To the internet to find out the difference!

Any other cons of a supercharger for a TJ the OP should be aware of?
 
A turbo and supercharger are totally different.

There are no cons to a supercharger setup on a TJ, as long as it's done right and you're running a realistic amount of psi.
 
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Superchargers and Turbos are VERY different animals that accomplish the same goal...Increase the pressure of the incoming air. More pressure equals more oxygen. More oxygen means more fuel...which equals more power.

Turbos are driven off exhaust gasses (which is why they get hot). I don't know about your scenario of it cracking...a well designed system shouldn't run that hot. Superchargers are belt driven from the crankshaft. They both have their pros and cons
 
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Tj04 said:
Makes sense. I also figured the two were the same, judging from your response they are not. To the internet to find out the difference!

Any other cons of a supercharger for a TJ the OP should be aware of?
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Bolt on? Just make sure the engine is sound before you add forced air induction. Good valve train, reasonably equal compression, transmission and transfer case up to snuff, etc. If you have issues in your ignition system, forced air induction will show that up in short order. The oiling system for superchargers and turbos need to be absolutely reliable and bullet proof to make them live a long and healthy life. An intercooler is worth the time and effort as it will decrease the chances of detonation or preignition. You're going to probably want to run premium fuel. Oh, make sure the rev limiter works and is set correctly. A blown drive line part or missed shift can have drastic consequences with a forced air induction system.

Superchargers will increase torque and horsepower from just off idle with no lag to speak of. Turbo's are getting to be the same way, but they have to be sized correctly on the turbine side and on the compressor side.

Full on custom? There's a lot to consider. Compression ratio, combustion chamber volume / matching, piston cooling, ring configuration, valve setup, cam profile, crank and rod modifications, exhaust mods, intercoolers, water / alcohol injection, fuel supply and injection, vacuum operated accessory modifications, head gasket design and mods... I built a blown, injected Mouse motor back in the late '70's. It was a thing of beauty and produced awesome power. What I should have done, upon reflection, is just plugged in a crate Rat motor and been done with it. There is no substitute for cubic inches in the pursuit of performance. A super/turbocharger just makes your engine think it's larger than it really is. That's the bottom line.
 
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My bad for giving false warnings. As you can tell I have zero interest in turbos and superchargers and actually am fine with my engine the way it is. :D (This is not supposed to sound condescending or anything.)

I could totally see the appeal especially with e.g. 35s where the 4.0 starts to Seem like a 4cyl
 
Tj04 said:
What about meth injectors? My friend had a truck with one of those in it along with a turbo. Those have any place in your informative post, @StG58 ?
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Yup, about the middle of the spew up there. Water / alcohol injection. That's been in use since WWII, my Dad was an airplane mechanic. He solved a detonation problem for me with that setup.

That's also how they got WEP or war emergency power in the big Packard and Rolls Royce engines. I guess they were good for about five minutes of that and then they were junk.
 
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Chris : What have been the advantages to your Charger, on and off road. I know nothing about them, nor "boost", so when you talk about 6 psi, what is that, translated into how it reacts or affects the jeep ? In your opinion, would there be any advantage for me with my never ending trips to California from Colorado ?

Ray
 
CMTJ said:
Soo, who makes a good charger and what would said charger cost?? Asking for a "friend" lol
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Can't answer that, because it's been a long time since I messed about with forced air induction. When I did mine, I used a 4-53 GMC roots style compressor and reworked the drive, vanes and nose. Custom oiling setup. That was for a scratch built Chevy DZ code mouse motor, and it worked really well.

There are superchargers out there for the 4.0. @Chris has one on his rig and has said he likes it. I also heard that Blaine had one on a TJ that was impressive.
 
CMTJ said:
Soo, who makes a good charger and what would said charger cost?? Asking for a "friend" lol
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https://www.boostedtech.com/

Expect to spend around $2500.


WWII Jeeper said:
Chris : What have been the advantages to your Charger, on and off road. I know nothing about them, nor "boost", so when you talk about 6 psi, what is that, translated into how it reacts or affects the jeep ? In your opinion, would there be any advantage for me with my never ending trips to California from Colorado ?

Ray
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It totally transforms your 4.0. You'll have around 230hp a the wheels (which is a lot) and you'll never have a single problem going up a hill or passing someone on the highway, even with 4 people in the Jeep and tons of weight.

All I can say is that it's a night and day difference. You'll feel like someone almost doubled the power output.
 
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Chris said:
https://www.boostedtech.com/

Expect to spend around $2500.




It totally transforms your 4.0. You'll have around 230hp a the wheels (which is a lot) and you'll never have a single problem going up a hill or passing someone on the highway, even with 4 people in the Jeep and tons of weight.

All I can say is that it's a night and day difference. You'll feel like someone almost doubled the power output.
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I know it's a Jeep, a shoe box in the wind tunnel of aerodynamics, but how did the charger affect the gas mileage ?
 
WWII Jeeper said:
I know it's a Jeep, a shoe box in the wind tunnel of aerodynamics, but how did the charger affect the gas mileage ?
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At first, negatively, because it was so fast I was always on the gas!

However, after I adjusted and got used to it, I'd say I maybe lost 1mpg if that.
 
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