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Discussion Starter #1
I just wanted to post a consumer report type warning to any 2012 to current JK owners considering the purchase of a Magnuson Supercharger. This primarily pertains to automatic transmission models and cannot verify manual issues. I am not here to bash the manufacturer or promote another alternative. I just wanted to share my personal experience with this system and pass along the information to the Jeep community.

Some quick facts: Installed on a 2012 JKU sport w/auto. 4.88 gears, 37" tires and 14K miles.

I purchased one of this unit a couple months ago and am completely disappointed with the overall drivability. This system has 2 primary issues. The first one is the inherent "surging". This surging feels like a misfire or hesitation. At wide open throttle this is not an issue but regular commuting at various RPM ranges and gears it is very noticeable. There was one update that I received that addressed this and it did improve but still very much there. I suspect in time this may be something that eventually will get dialed in. They will not automatically send you updates. You will have to check in periodically and ask.

The second and most notable issue / complaint about the Magnacharger is the automatic transmission shifting points or lack thereof. Here is the problem. Under normal driving conditions the transmission will hold the current gear and does not want to upshift at any type of normal range. here is an example. If you were to take off from a dead stop and apply approximately 20 to 40% throttle and hold it there, hear is what you can expect. 1st to 2nd gear is usually (I emphasize usually) pretty normal. 2nd to 3rd will shift around 3000 to 3400 RPM's. 3rd to 4th would be somewhere around 3800 to 4500 RPM's and you can all but forget about 5th. From 4th to 5th it is hold around 5000 RPM's and in many cases not shift at all until you completely take your foot off of the throttle. This shifting combined with the surging makes for a pretty un-pleasurable experience to say the least. I hate driving in fact.

The biggest disappointment is the lack of a fix. I contacted Magnuson to express my problems only to find out they were well aware of it. I was confused as to why this system would have been released knowing of this? The response was "there is no way we could have tested every Jeep configuration". This is true (and not expected) but they went on to say it only seems to affect "lifted Jeeps with larger tires and / or gear changes" (that's probably only 95% of Jeep owners that would be willing to invest in a supercharger but lets give him the benefit of the doubt) He went on to say "we have also seen this in Jeeps that have not had tire and / or gear changes and is not a Magnuson specific issue". Well okay then this must be a Chrysler issue, I am sorry for bothering you with my nonsense. Oh wait.....here are a few FACTS taken directly from my e-mail to them

1. Purchased Jeep at 7K miles bone stock with no transmission or any other issues.

2. Installed lift, tires, gears, recalibrated etc. at 10K miles and zero issues with transmission or anything else on or off-road.

3. Installed Magnuson Supercharger at 14K miles and now have both issues mentioned above.

Magnuson then went on to point the finger at Diablo because they have not decoded the transmission parameters. Wait....You guys chose this tuner for your system knowing they have not decoded the tranny. How is that a Diablo problem? Anyway the fact is, it is my problem now.

Conclusion: There is no current fix or any type of timeframe projected. This is from both Magnuson and Diablo. Is there something else I would have spent 6k plus on? If you own an automatic 3.6L Wrangler I would proceed with extreme caution. In truth there is no F...ing way I would by this system.
 

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I understand you've spent money and been burned. That really :mooning: stinks! But can you at least reset your computer to stock so you enjoy driving your jeep again? If you can't, that would REALLY :censored: stink!

Hopefully updates will come sooner than you anticipate. Good luck!
 

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Do you have an auto locker in the rear?
 

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Sounds like you can ether pay for a local tuner who can work with jeeps or figure out the problem yourself. IMO I wouldn't even FI a engine without getting a solid tune from myself with the right equipment or from a pro shop. I'd assume the hardware with the supercharger is fine it just needs to be tuned right.
 

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Thanks for bringing this to everyone's attention. People can make their own decisions about whether to purchase from a particular aftermarket entity, but I would have a very hard time buying a Magnuson or Diablo product after reading this. If someone from either of those two companies is reading this, they should know that there are probably many, many other people reading this that feel the same way and won't bother to post anything.
 

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I was on the cutting edge of 03 cobra tuning way back then and ran into nothing but problem after problem. It was probably 4 years and melted pistons to get everything ironed out and running flawlessly. What you are running into is pretty common. It takes months and sometimes years for the tuners to learn all the ins and outs of the various PCM's and until they do you are at their mercy.

As mentioned, I would try and find a local tuner very familiar with JK's who has a dyno.
 

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Discussion Starter #7
Thanks for the feedback. I may look into a local shop for options. The main problem seems to be the trasmission mapping not the engine tune. The two are not talking to each other at the moment. According to Magnuson and Diablo decoding the transmission is a long and tedious process. That I can understand. I am frustrated because I was unaware of this at the time of purchase / install. Now it's already done and it leaves me with very few options not to mention the expense and time frame. I live in Michigan where our Jeepin season is somewhat short. We leave our Jeep at our summer place for 5 months just outside of the dunes where we primarily wheel.

To answer a couple questions.
1. No auto locker in rear. Curious as to why?
2. You cannot reset the the computer back to stock because it will not run with the supercharger installed.
 

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Discussion Starter #10
Im sure this is addressed with the Diablo tuner but just noticed this. "For Jeeps with larger tires than stock or non-stock gearing, you will need an AEV Procal to adjust the tune " https://www.magnacharger.com/p-126-jeep-wrangler-36l-jk-2012-2014-magnuson-supercharger.aspx
Magnusen told me originally that I could not use the Diablo tuner to make tire / gear changes even though the tuner allows for this. My calibration was already done prior to the install and part of the original file I sent to Magnuson so they could then send me their mapping for the charger. They did mention the ProCal on the front end but after seeing my file said it was good and not necessary.
 

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Just out of curiosity, do you still get the surging if you operate the tranny in manual mode? That is obviously going to eliminate the erratic shift points, but takes away from the whole idea of having an auto trans.
 

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Discussion Starter #12
Just out of curiosity, do you still get the surging if you operate the tranny in manual mode? That is obviously going to eliminate the erratic shift points, but takes away from the whole idea of having an auto trans.
The surging is still there in manual mode but it does make the shifting better to a degree. The problem with the "manual mode" on these Jeeps is it's only a partial manual. The computer still overrides your input based on throttle position. For example if you are a little heavier in the pedal and up shift at 3500 rpm's it will still hold the gear until the computer decides to up shift. This is something I noticed right after I bought the Jeep and prior to any mods. I felt because of the computer doing what it wants to do anyway it renders the manual mode pretty worthless in my opinion. If I had known this I probably would have done with a manual from the beginning as I wouldn't be experiencing half the problems I am having.
 

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Sorry to hear, of all the superchargers out there for the JK I'd want the Magnuson.

I've read similar gripes with other setups, so you're not alone. The ECM on these Jeeps must really be a bitch to re-program properly.....
 

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nail in the coffin for me planning any FI on my JK for at least another year to see if any of these manufacturers can get the tuning right. While Diablo is what most of them use it sounds like Diablo is the source of some or a lot of the issue and unfortunately as has been said it may not even be there fault but that the system is so guarded by Chrysler.
 

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nail in the coffin for me planning any FI on my JK for at least another year to see if any of these manufacturers can get the tuning right. While Diablo is what most of them use it sounds like Diablo is the source of some or a lot of the issue and unfortunately as has been said it may not even be there fault but that the system is so guarded by Chrysler.
I don't understand why you would even rely on someone who is providing the hardware to also have a generic tune that would work for every JK. You should have the mindset when buying a FI kit that you would need it tuned in a shop (not from sending and downloading new tunes on the web) to get it working perfect. I'm sure if you went to their shop it would be a lot different but doing a tune over the web just sounds a bit risky for a new jeep.
 

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I don't understand why you would even rely on someone who is providing the hardware to also have a generic tune that would work for every JK. You should have the mindset when buying a FI kit that you would need it tuned in a shop (not from sending and downloading new tunes on the web) to get it working perfect. I'm sure if you went to their shop it would be a lot different but doing a tune over the web just sounds a bit risky for a new jeep.
"I" wouldn't rely on a canned tune. I don't think anyone has the ECU and transmission control unit hacked completely yet regardless. I would do as should be done. Buy FI, run canned tune from my house to a competent tuner and get both dyne and road tuned. At this point it won't matter as there are not very many tuners in my area of the east coast along with nobody having the ability to custom tune a Jeep anyway. Shift points wouldn't change at a shop or in the mail.
 

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You cannot change the shift point on the nag1 yet the lx "charger/challenger" guy have some work around but nothing great.
Well i'm not sure it could be done but you would think that would be one of the first things you would attempt to figure out before you release a kit with a bundled tune for a auto.
 

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Well i'm not sure it could be done but you would think that would be one of the first things you would attempt to figure out before you release a kit with a bundled tune for a auto.
They have supercharging lx cars for years without cracking the tcm I wouldn't hold my breath and at the end of the day its not mandatory for a proper tune. Its just going to take time and the early adoptors are the testers.
 
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