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I'm thinking about eventual performance mods for my 2016 SRT 392. Supercharging seemed like the most direct method for increasing power, since it doesn't require you to tear into the engine at all. It is technically a "bolt-on" setup I suppose. I thought that might make my extended warranty company more sympathetic to me if anything ever went wrong with the engine. Also, got to love that supercharger whine.

Who makes the best roots style setup for our cars? The Whipple 2.9L seems to be the most popular option but I'm told Magnuson does good stuff too.

Is there any reason to go with the Procharger centrifugal setup over a positive displacement roots blower?

Can the 6.4 safely handle 6-7 PSI of boost over the long term? Like 5 years and 100,000 miles plus long term? It's my daily driver. Currently has 31,000 on it now.

Can the HP70 transmission be tuned to safely and reliably handle these kinds of power levels?

Does boosting hurt daily drivability as long as it's well tuned?

How does the power delivery compare to NA motors?

Does the added weight in the front end hurt the weight distribution or handling ability in any appreciable sense?

Are there any supporting mods necessary for this low of a boost level? Like a new fuel pump?

What kind of power am I likely to see at the rear wheels with 6-7 PSI?


The other direction I'm considering going is a full bolt-on and new cam build, possibly with a stroker kit in there. An NA cammed 426 build would be pretty sweet, and for this kind of build Modern Muscle tells me I could expect 500-525 at the wheels without a stroker kit, and 575+ with.

My main considerations are:

  • Long term longevity and reliability
  • Cost effectiveness (dollar for horsepower)
  • Mechanical difficulty and skill needed
Whichever direction I go, I really want to learn how to do all the work myself (except for the tuning), so I'm not really thinking about the labor costs. Unless maybe it's a bad idea for an amateur to tackle a cam swap?
 

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Use the search function this topic comes up quite frequently. In fact there is a recent thread discussing this.
 

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I'm thinking about eventual performance mods for my 2016 SRT 392. Supercharging seemed like the most direct method for increasing power, since it doesn't require you to tear into the engine at all. It is technically a "bolt-on" setup I suppose. I thought that might make my extended warranty company more sympathetic to me if anything ever went wrong with the engine. Also, got to love that supercharger whine.

Who makes the best roots style setup for our cars? The Whipple 2.9L seems to be the most popular option but I'm told Magnuson does good stuff too.

Is there any reason to go with the Procharger centrifugal setup over a positive displacement roots blower?

Can the 6.4 safely handle 6-7 PSI of boost over the long term? Like 5 years and 100,000 miles plus long term? It's my daily driver. Currently has 31,000 on it now.

Can the HP70 transmission be tuned to safely and reliably handle these kinds of power levels?

Does boosting hurt daily drivability as long as it's well tuned?

How does the power delivery compare to NA motors?

Does the added weight in the front end hurt the weight distribution or handling ability in any appreciable sense?

Are there any supporting mods necessary for this low of a boost level? Like a new fuel pump?

What kind of power am I likely to see at the rear wheels with 6-7 PSI?


The other direction I'm considering going is a full bolt-on and new cam build, possibly with a stroker kit in there. An NA cammed 426 build would be pretty sweet, and for this kind of build Modern Muscle tells me I could expect 500-525 at the wheels without a stroker kit, and 575+ with.

My main considerations are:

  • Long term longevity and reliability
  • Cost effectiveness (dollar for horsepower)
  • Mechanical difficulty and skill needed
Whichever direction I go, I really want to learn how to do all the work myself (except for the tuning), so I'm not really thinking about the labor costs. Unless maybe it's a bad idea for an amateur to tackle a cam swap?
No supercharger/turbo charger installation experience but I looked into this years ago for a car. I didn't go the supercharger/turbo charger route but I did build an engine, install an aftermarket cam, fit dual side draft Weber carbs, and did some other things with no real formal automobile tech training. 'course, this was not my first exposure to this level of engine work/mods though.

Do not know what roots or positive displacement type of supercharger is best. To me the concern is how stacking a supercharger on top of the intake manifold which has to blow through an inter cooler affects the stock hood fit.

Maybe you are ok with a supercharger sticking out of the hood but I'd be worried about blocking my sight. Yeah, the Hellcat doesn't have a problem but it had the deep pockets of Dodge to come up with a compact intake manifold, inter cooler and supercharger to get it all to fit.

The centrifugal supercharger seems to be a bit easier to plump as the supercharger doesn't sit on top the engine but can be located in front and to one side just like an another accessory drive although I believe it requires its own drive and can't share this. These superchargers are sealed and lubed and should last a long time. Sure the supercharger on say the Hellcat is sealed and lubed but its rotors operate in very close proximity to each other and in fact are coated with something to deal with any rotor to rotor contact. With a centrifugal supercharger there is no contact with the spinning compressor and the housing.

From my research around 6psi of boost is ok provided the engine is healthy, fueled correctly which can mean a higher capacity fuel pump, filter, and fuel lines -- in the case of the engine I mod'd I added an electric fuel pump and a larger capacity filter and an adjustable fuel pressure regulator to ensure the Weber carbs received clean and sufficient fuel of the proper pressure -- and has a proper tune, has no issues like marginal or compromised cooling.

Speaking of cooling: A bigger radiator might be called for. Remember the engine can be producing a rather large additional amount of power and this means more heat. The 6.4l engine might be making the power of -- just a number -- a 7.4l or even larger engine.

Speaking of HP keep in mind to produce another 100hp of crankshaft or rear wheel HP the supercharger requires considerable power to operate. Thus to get 100hp bump the engine might have to produce 125hp or more the extra going to spin the supercharger.

Beside the supercharger you need to think about an inter cooler. While a liquid cooled inter cooler doesn't drop the intake air temperature down as well as a (good) air cooled inter cooler it is a heck of a lot easier to plumb.

But see what the supercharger kit makers have to offer in the way of inter coolers. Maybe they've worked something reasonably easy to install?

Added weight to the front will probably be the least of your worries.

As for the transmission most of the mod'd engines I was exposed to were working through a manual. But a couple were equipped with an automatic. In this case the guy doing the engine work also at some point dropped the automatic and installed some upgrades though I can't recall now what they were -- maybe a high capacity transmission fluid pump -- and installed a "shift" kit to improve the speed at which the clutches (band?) engaged to reduce the amount of slippage. The torque converter acted as a cushion between the engine and transmission/drive train. Depending upon usage a higher capacity transmission oil cooler may be called for.

The stock transmission will probably be ok but if you make max use of the additional HP often you might need to think about beefing up the stock transmission or even installing a heavier duty transmission.

The diff might need attention too.

The supercharger kit makers I'm sure provide estimated HP gains. I refer you to their web sites and kit info for that.

Also, the documentation I seem to recall covers installation difficulty and what other mod's might be necessary like in the case of turbochargers the oil return line plumbing.
 

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I thought that might make my extended warranty company more sympathetic to me if anything ever went wrong with the engine.
Sorry, but thats not going to happen. Impossible to "hide" a supercharger from service techs. just as hard to hide the PCM tune, etc as well, which is needed to run this mod. That would all trickle down into any driveline, trans, coolinhg, electronics issues/failures..least from their standpoint.
You'd be screwed, probably for much (if not all) of the warranty. No doubt such 'evils' are well spelled out in your warranty paperwork.
 

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Discussion Starter #6
No supercharger/turbo charger installation experience but I looked into this years ago for a car. I didn't go the supercharger/turbo charger route but I did build an engine, install an aftermarket cam, fit dual side draft Weber carbs, and did some other things with no real formal automobile tech training. 'course, this was not my first exposure to this level of engine work/mods though.

Do not know what roots or positive displacement type of supercharger is best. To me the concern is how stacking a supercharger on top of the intake manifold which has to blow through an inter cooler affects the stock hood fit.

Maybe you are ok with a supercharger sticking out of the hood but I'd be worried about blocking my sight. Yeah, the Hellcat doesn't have a problem but it had the deep pockets of Dodge to come up with a compact intake manifold, inter cooler and supercharger to get it all to fit.

The centrifugal supercharger seems to be a bit easier to plump as the supercharger doesn't sit on top the engine but can be located in front and to one side just like an another accessory drive although I believe it requires its own drive and can't share this. These superchargers are sealed and lubed and should last a long time. Sure the supercharger on say the Hellcat is sealed and lubed but its rotors operate in very close proximity to each other and in fact are coated with something to deal with any rotor to rotor contact. With a centrifugal supercharger there is no contact with the spinning compressor and the housing.

From my research around 6psi of boost is ok provided the engine is healthy, fueled correctly which can mean a higher capacity fuel pump, filter, and fuel lines -- in the case of the engine I mod'd I added an electric fuel pump and a larger capacity filter and an adjustable fuel pressure regulator to ensure the Weber carbs received clean and sufficient fuel of the proper pressure -- and has a proper tune, has no issues like marginal or compromised cooling.

Speaking of cooling: A bigger radiator might be called for. Remember the engine can be producing a rather large additional amount of power and this means more heat. The 6.4l engine might be making the power of -- just a number -- a 7.4l or even larger engine.

Speaking of HP keep in mind to produce another 100hp of crankshaft or rear wheel HP the supercharger requires considerable power to operate. Thus to get 100hp bump the engine might have to produce 125hp or more the extra going to spin the supercharger.

Beside the supercharger you need to think about an inter cooler. While a liquid cooled inter cooler doesn't drop the intake air temperature down as well as a (good) air cooled inter cooler it is a heck of a lot easier to plumb.

But see what the supercharger kit makers have to offer in the way of inter coolers. Maybe they've worked something reasonably easy to install?

Added weight to the front will probably be the least of your worries.

As for the transmission most of the mod'd engines I was exposed to were working through a manual. But a couple were equipped with an automatic. In this case the guy doing the engine work also at some point dropped the automatic and installed some upgrades though I can't recall now what they were -- maybe a high capacity transmission fluid pump -- and installed a "shift" kit to improve the speed at which the clutches (band?) engaged to reduce the amount of slippage. The torque converter acted as a cushion between the engine and transmission/drive train. Depending upon usage a higher capacity transmission oil cooler may be called for.

The stock transmission will probably be ok but if you make max use of the additional HP often you might need to think about beefing up the stock transmission or even installing a heavier duty transmission.

The diff might need attention too.

The supercharger kit makers I'm sure provide estimated HP gains. I refer you to their web sites and kit info for that.

Also, the documentation I seem to recall covers installation difficulty and what other mod's might be necessary like in the case of turbochargers the oil return line plumbing.
Jeez...yeah, I think I'll just go the naturally aspirated route. If I ever want a supercharger I'll go for a used Hellcat.
 

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Its alot to take in lots to consider. If it was my daily I wouldn't get crazy but that's me others would probably differ. I've been slowly building my 392 for 4 to 5 years now bought a sc then later forged the motor added other components through out the years never seem satisfied with the power but I like to wrench on it . If it is your daily and worried about warranty issues keep it stock and or get the cat.
 

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Whether you go SC or NA, if you have engine problems, your extended warranty will not cover it. If you want to keep that part of your extended warranty, you'll need to either take your chances, or keep it stock

See the numbers a Maggie at 6psi will give you


A good tune is vital for the engine to live!

A Guy
 

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When used Hellcat prices were still out of sight (and out of most peoples reach) an aftermarket supercharger option made more sense to me.
NOT NOW.
IMHO' you are way ahead by simply trading up to a used Hellcat. The prices have fallen considerably and there are a lot of clean low mileage cars available.
 

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I wouldn't do it if it was my daily driver and I didn't have a back up. The problem with the 6.4 is you can't throw much boost at it. Do you really want to spend over $10k to have 6-7lbs of boost.
 

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for the millions' th time, anything beyond a cold air intake and cat back exhaust will affect your warranty......

if your supercharging a 6.4 plan on changing short block or building a short block......max boost level is 6 to 7 psi, and still with the poor quality of fuel across the country, good chance you will still have a failure

a max build 426 na, with Thitek heads, with large tbi and ported intake, high quality long tubes and high flow cats will deliver approx 550 wheel horsepower

huge difference between na and boost power
 

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5.7 will easily live on 8 psi of boost, with upgrade fuel system, Kooks long tube sand green catted high flow cats will deliver 500 whps and 500 ft/lbs

stock internal
 

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Jeez...yeah, I think I'll just go the naturally aspirated route. If I ever want a supercharger I'll go for a used Hellcat.
You seriously need to consider it.

Generally the best hot rod is the one the factory offers. IOWs, instead adding a supercharger to an RT get a Scat Pack.

Instead of supercharging a Scat Pack get a Hellcat.

While the cost up front looks steep over the long run it will be the cheaper way to go.

Years ago factory supercharged/turbocharged cars were rare. In my price range -- which excluded any exotics -- about all I can recall is the BMW 2002 Turbo. My urge to turbocharge my car was dampened when the gas crisis hit. Gas lines. 55mph speed limits. And (for back then) high gas prices.

I turned my attention to other things which involved among other things career changes which worked to up my income substantially which was a good thing, to state the obvious.

After a few years after buying a vehicle, a pickup truck, that primarily was selected for my business needs I started buying cars again. The 1st one was not a hot rod by any stretch but then came the Mustang, Camaro, Porsche, GTO, another Porsche, then another (this one with 2 turbos!), then a Scat Pack, the MINI JCW, and most recently the Hellcat.

Nowadays a good number of cars are at least equipped with a turbocharger. (My 2018 MINI JCW has a turbocharged engine.)

In the case of the Scat Pack and Hellcat Dodge has done the heavy lifting at both the engine and the car. The engine is built from the ground up with in the case of the Scat Pack its 485hp output in mind or in the case of the Hellcat its 707hp (via of course supercharging) in mind. Likewise, the car -- Scat Pack and Hellcat -- is built from the ground up with the engine in mind.

You don't have to buy new. There are used ones. Not all are thrashed. 'course, you have be thorough in your inspection/vetting of the car before you buy it.
 
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