Toggling a Supercharger

SSTJ

SSTJ

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This Jeeper installed an Eaton supercharger on his YJ. The supercharger is clutched, and he uses an Arduino to toggle the supercharger on and off.

Has anyone done anything similar (toggling) on a TJ? I wonder if the TJ's PCM makes it any easier or any more difficult?
 
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I don’t see the point in it
 
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SSTJ said:
This Jeeper installed an Eaton supercharger on his YJ. The supercharger is clutched, and he uses an Arduino to toggle the supercharger on and off.

Has anyone done anything similar (toggling) on a TJ? I wonder if the TJ's PCM makes it any easier or any more difficult?
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I'd bought a supercharger for my 4 cyl about 4 months before I'd decided to do the V-8 swap. I missed buying a older Avenger supercharger while I was in Iraq too. This is the first time I'd seen a clutched version though. If you look on Pirate there were some guys who did a DIY version on their Jeeps.
No I don't think the TJ PCM would make it any easier to do. Back when I was looking into doing a supercharger or turbo the only way to manage the added fuel requirements was SplitSecond but now with the tuning available from what I understand you don't need to use them.
If you're seriously interested in forced induction I'd talk with Ryan at FRP first and see what is available to tune your engine.
 
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I spoke with Isaiah at FRP. He explained that it wouldn't be possible to toggle the PCM from one tune to another. Instead, one would want a tune that works as usual when the engine when running normally, and yet also accommodates changes when the supercharger is switched on.

I asked whether he had seen any examples of this, and he pointed to a few common builds that involve clutched superchargers. But those superchargers are triggered by load, not by a switch. He's going to talk with Ryan and then we'll talk again.
 
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Had another quick chat today. Isaiah and Ryan weren't clear on how to toggle the supercharger itself, so I shared the same video as above. But if that can be done well, they seem confident that the PCM can be tuned to accommodate both stock performance and the occasionally-engaged supercharger. I'll follow up again after they've seen the vids.
 
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SSTJ said:
I spoke with Isaiah at FRP. He explained that it wouldn't be possible to toggle the PCM from one tune to another.
Click to expand...

Google dsp5 switch and then wish you didn't have 4 squirrels and lazy gasoline tuners. Gm,dodge and maybe ford diesel pcm's could all accommodate on the fly tune changes
 
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Didn't watch the video but seems pointless to me. I want that boost on tap all the time. And my supercharged Jeep isn't even a 4 banger.

If you need it you have it, and if you don't need it then you're not in boost. Maybe the clutch is just to reduce the parasitic drag on the engine when it's not in boost? I'd think that would be fairly negligible, like you're in the wrong vehicle to begin with.
 
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I’ve run a supercharged I-6, and here is my take. The issue is that if you drop in a supercharger, and make no changes to the tune, you will smoke the engine from a lean condition in no time flat. There is that much difference, and the stock ECU cannot make changes to accommodate the additional airflow.

Since you can’t have a stock ECU make enough change to protect the engine, and you can’t swap tunes on the fly, you must put a tune in to work with the supercharger. That basically means much more fuel at every RPM.

That means when the clutch disengages the supercharger, you are running crazy fat on fuel - it’s not going to smoke the engine, but any expected fuel savings from disengaging the supercharger will not materialize.

Add to that the fouled plugs, etc…
 
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Tuning for a toggled-supercharger shouldn't be much different than for a turbocharger. It doesn't need to directly know if it's on or off, fuel maps are tied to manifold pressure.

The only benefit, besides the cool factor, would be slightly better gas mileage.
 
SSTJ said:
Honestly no good reason. Just interested and curious. Seems like a supercharger's version of a turbocharger's waste-gate, if I even understand that correctly.
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The supercharger when installed similar to the Boosted Technologies method, already toggles on and off as needed. It is a 100% demand based system and when the demand is there, it moves out of vacuum into boost seamlessly. If you install a boost/vacuum gauge, you can watch it happen in real time. Cruising along in OD, start up a big hill, gauge moves out of vacuum, goes into building boost, goes up hill, and the only way you would know is by watching the gauge and the fact that it never went up that hill before in OD.

The only reason to put a toggle switch of sorts on a supercharger is if you are highly confused and think it works like nitrous, it doesn't. The boost is there when the demand is there and when the demand isn't, the boost isn't.
 
NashvilleTJ said:
I’ve run a supercharged I-6, and here is my take. The issue is that if you drop in a supercharger, and make no changes to the tune, you will smoke the engine from a lean condition in no time flat. There is that much difference, and the stock ECU cannot make changes to accommodate the additional airflow.

Since you can’t have a stock ECU make enough change to protect the engine, and you can’t swap tunes on the fly, you must put a tune in to work with the supercharger. That basically means much more fuel at every RPM.

That means when the clutch disengages the supercharger, you are running crazy fat on fuel - it’s not going to smoke the engine, but any expected fuel savings from disengaging the supercharger will not materialize.

Add to that the fouled plugs, etc…
Click to expand...

Thanks. That's what I was wondering. Somehow the YouTuber I linked above has made it work on a YJ. So, was wondering if the same would be easier or harder with a TJ. Again, mostly out of curiosity, not for some supposed reason or purpose.

srimes said:
Tuning for a toggled-supercharger shouldn't be much different than for a turbocharger. It doesn't need to directly know if it's on or off, fuel maps are tied to manifold pressure.

The only benefit, besides the cool factor, would be slightly better gas mileage.
Click to expand...

In speaking with Isaiah at RFP, that's what he seemed to be saying. You can't toggle a tune, so you just need a tune that would accommodate both conditions.

mrblaine said:
The only reason to put a toggle switch of sorts on a supercharger is if you are highly confused and think it works like nitrous, it doesn't. The boost is there when the demand is there and when the demand isn't, the boost isn't.
Click to expand...

Thanks. I was indeed under the impression that superchargers are "always on", being driven directly by a belt with (typically) no clutch on the unit. I thought it was turbochargers that responded more to load/demand.

But I don't mean to turn this thread into a tutorial for me alone. For now, I just wanted to ask about whether this toggling feature was common, and whether it would work on a TJ as well as it seems to work for the YJ linked above.
 
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