Just a question since I dont know much about these, but could it be that these dont whine as much due to running such a big pulley and small boost? Ive seen a lot of muscle car youtubers and they always post vids of upgrading to a smaller pulley(more boost) and they whine like crazy. For instance, if you ran 20psi out of that charger with a smaller pulley do you think it would whine more vs the current size pulley and 8 psi?
Do I need to strengthen my engine for a supercharger?
- Thread starter Cwcarp59
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- supercharger tj 4.0
SPECWAR
TJ Enthusiast
That’s a problem in a lot of some parts of the country.
I’m sure it was.
I’m going to start playing with E85 as soon as I get a few other projects done.
I'm not convinced that we aren't actually hearing the straight cut gear whine.
Turn it up.
SPECWAR
TJ Enthusiast
The faster you spin the blower the more whine you will get.
Out of all fairness, I have heard a few Eaton M90’s that have been ported and new rotor blades installed, that don’t make as high of a pitched whine. But it’s still noticeable, especially if your in front of the vehicle.
Next time you visit a drag strip where they have blower ( supercharged) cars, stand at the trap end of the track when they run. All you will hear is the whine of the blowers until they reach your location.
SPECWAR
TJ Enthusiast
Hard for me to differentiate from your clip. Blower whine increases with rpm as you surely are aware. Maybe a little combination of both in your case.
Sure as hell looks like fun though!!
I’m stuck in that straight 1320 foot world.
Yeah thats definetly straight cut gear whine. As you upshift the wine will increase in pitch. Like specwar said though, supercharger whine will increase with RPM and when you shift the wine will fall in pitch/ noise, due to Rpms falling. But my question still stands, wouldnt more boost cause more whine? @Chris maybe you can be the test subject while blaine has your jeep
Yeah thats definetly straight cut gear whine. As you upshift the wine will increase in pitch. Like specwar said though, supercharger whine will increase with RPM and when you shift the wine will fall in pitch/ noise, due to Rpms falling. But my question still stands, wouldnt more boost cause more whine? @Chris maybe you can be the test subject while blaine has your jeep
I doubt Blaine has a spare supercharger laying around or that he wants to waste the time to test something like this (which I wouldn't blame him for).
Go get an unmuffled Lysholm supercharger or an early Vortech V1 if you want to hear some serious whine.
I was joking lol, no one should be running 20psi on a 4.0 just to hear some whine if any
I was joking lol, no one should be running 20psi on a 4.0 just to hear some whine if any
Yep! I am going the N/A route on my current rig. It should be just fine for the way I use it.
SPECWAR
TJ Enthusiast
Got my introduction to FAI by crew chiefing this car based out of the Portland Oregon suburbs in 1976.
So Chris, given at one time you so were positive about the MAGNUM supercharger what changed your mind?
I still think it's a great supercharger as long as you aren't foolish enough to believe it's a "kit".
You'll end up putting around $2000 or more into making it run right. I also think the fact that it requires the use of an aftermarket radiator, an electric fan, and has a history of overheating issues in warmer climates due to this is a potentially big deal.
You can obviously solve those issues, but again, you're going to spend at least $2000 or more on top of the kit to get things sorted out, not to mention you'll still need to invest time and money in some good dyno tuning in order to get it running really good.
At the end of the day, it's just not worth it to me. In terms of superchargers, I think it's the best one for a TJ. However, I'd pick a turbo any day over a supercharger if I wanted to go down this path again.
Nope, that I can't say.
However, given what I have seen from others, the Eaton M90 with 6-7 psi should be putting down around ~210 HP at the wheels on a Mustang dyno and the Magnum Powers should be putting down closer to 230-240 HP.
Lots of variables here though, lots.
Year ago I bought an 03 Rubicon with a Blaire Built supercharger installed. This was a rename of the original Rick Rimmer design that now looks to be sold under the name Boosted Tech. It used a intercooler and 7th injector. After researching more about the design and designer I chose to remove it. I can't remember specifics but there were concerns with it causing the engine to run very lean. The manufacturer claimed that the 7th injector eliminated the need for tuning software. At least the Boosted Tech supercharger no longer makes that claim. I lived in Colorado at the time and will say the supercharger made a noticeable difference at higher elevations, just not enough to risk my engine.
SPECWAR
TJ Enthusiast
You’re correct, variables are numerous.
Now, educate me on this. With the $$ involved with superchargers and turbos, why not just convert to LS power? 4.8 or even a 5.3? Damn near indestructible and great stock HP and torque numbers.
Cost and if one does actual realistic costs, that swap never pencils out unless 20 grand for a motor swap makes sense to anyone.
The OP should only listen to those that have actually used forced induction a Jeep 4.0. Comparing other engines is not apples to apples. Some engines accept boost more readily than others. On the 4.0 the safe boost limit for an unmodified engine is about 9 - 10 lbs of boost with enrichened fuel mixture and some degree of timing retard. What typically fails first is the head gasket. If you use a multi layer steel head gasket and ARP head bolts or studs, you MAY be able to go to about 12 PSI. You have to monitor Air Fuel ratio and keep a keen ear for detonation.
I am running an Eaton M90 with 9 PSI of boost. It has been working well for almost 3 years now. My heavy 4860 lb LJ on 40s out-accelerates my wife's much lighter TJ on 35's and mine pulls uphill grades better as well.
The critical factor is getting the tune right. I am pulling 0 degrees of timing until 3 lbs of boost, about 1/2 degree per pound of boost up to about 4.5 lbs, and then 3/4 degree to one degree per lb of boost on up. I can buy 93 octane pump premium here in Central Texas. It does get very hot here during summer. In the winter, I let it inhale warm air from under the hood. In the hot summer months, I let it take in ambient air from the passenger wheel well. I just have a flexible duct that I can quickly install or remove with no tools that lets me make the switch.
The reason I do not like a turbo on a 4.0 that has the twin precats in the header, is that if the cats fail, they will blow chunks up into the turbo, which can take out the turbo. If the turbo suffers a catastrophic impeller failure, all the resulting shrapnel gets inhaled into the engine. After that, the motor would need a rebuild, if it is even salvageable.
It is doable to supercharge the 4.0. I would say it is for someone that likes to learn about it and tinker accordingly.
I am running an Eaton M90 with 9 PSI of boost. It has been working well for almost 3 years now. My heavy 4860 lb LJ on 40s out-accelerates my wife's much lighter TJ on 35's and mine pulls uphill grades better as well.
The critical factor is getting the tune right. I am pulling 0 degrees of timing until 3 lbs of boost, about 1/2 degree per pound of boost up to about 4.5 lbs, and then 3/4 degree to one degree per lb of boost on up. I can buy 93 octane pump premium here in Central Texas. It does get very hot here during summer. In the winter, I let it inhale warm air from under the hood. In the hot summer months, I let it take in ambient air from the passenger wheel well. I just have a flexible duct that I can quickly install or remove with no tools that lets me make the switch.
The reason I do not like a turbo on a 4.0 that has the twin precats in the header, is that if the cats fail, they will blow chunks up into the turbo, which can take out the turbo. If the turbo suffers a catastrophic impeller failure, all the resulting shrapnel gets inhaled into the engine. After that, the motor would need a rebuild, if it is even salvageable.
It is doable to supercharge the 4.0. I would say it is for someone that likes to learn about it and tinker accordingly.