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My first official thread on this forum and its already something some of you may find interesting. Recently I have been wanting to do something unique to my jeep and have ran into a few youtube videos that show people using Eaton m62 and m90 superchargers on their cherokees. One specific video caught my attention.
I really started thinking that this is something that I could probably do myself. So yesterday I went to the local junkyard and picked up a gen 3 m90 off of a Pontiac Grand Prix GTP. I will say this now, this is more of a proof of concept for me. I am not looking to make 12 lbs of boost like some guys are. I do have a 4.6 stroker so thats why I opted for an m90. I also am trying to do this as cheap as possible. I am not worried about fab work as much as I am about tuning and fuel. I hope you guys can pitch in some info and possibly learn a few things. Finally, I am getting much of my info from CobraMarty's previos threads and directly from him so I would like to thank him in advance!
Good choice grabbing a M90 vs M62 for your 4.6L stroker.
How does your stroker run now? What injectors are you using? Did you do a tune on the stroker?
Do you want to do a 'blow thru' or a 'draw thru'? That is where do you want to put the TB in relation to the SC, Before or after the SC. Realize that the SC will be putting out boost all the time at 1500+ rpm if it is set up as blow thru. Best is draw thru.
Get a ELM 327 Bluetooth OBD2 reader less that $10 on ebay or amazon and get Torque PRO $5 app store. Hook it up and watch and learn your engine now without the SC. Especially useful is the 'Fuel Status' page. That tells you if you are in open or closed loop. Watch and see what you have to do to get it into open loop. Only in open loop can you add the extra fuel needed for the SC and more power and prevent detonation and ruining an engine.
Good choice grabbing a M90 vs M62 for your 4.6L stroker.
How does your stroker run now? What injectors are you using? Did you do a tune on the stroker?
Currently runs great except it idles at 1000rpm instead of 750. Stock injectors but I picked up a set of 703s to throw in after loving the mod on my last jeep. Also there should not be any tune as I reset the PCM shortly after I bought it.
Do you want to do a 'blow thru' or a 'draw thru'? That is where do you want to put the TB in relation to the SC, Before or after the SC. Realize that the SC will be putting out boost all the time at 1500+ rpm if it is set up as blow thru. Best is draw thru.
I honestly thought that draw thru was the only option I had as it seems weird to force in air before the throttle body. I will use draw thru due to keep sensors close by the supercharger.
Get a ELM 327 Bluetooth OBD2 reader less that $10 on ebay or amazon and get Torque PRO $5 app store. Hook it up and watch and learn your engine now without the SC. Especially useful is the 'Fuel Status' page. That tells you if you are in open or closed loop. Watch and see what you have to do to get it into open loop. Only in open loop can you add the extra fuel needed for the SC and more power and prevent detonation and ruining an engine.
Can you explain open and closed loop a bit more to me? Also, I read some of your previous threads and people ended up buying that PCM addition that plugs into the last plug. Is there anyway I can avoid using that if I cut back on the amount of boost I create?
Any amount of boost requires extra fuel and timing retard. If you don't provide extra fuel during boost, you will have a lean AFR and detonate and blow your engine. If you don't have timing retard when in boost, you will detonate and blow your engine.
Closed loop the O2 sensor tells the ECU the AFR and the ECU commands fuel to make 14.7:1 AFR.
Open loop the ECU ignores the ECU and the ECU sends a preset amount of slightly richer fuel which is programmed into the ECU. This however is not rich enough for boost. But in open loop you can add additional fuel and the ecu will not dial back fuel trying to target 14.7:1 like in closed loop.
The are many strategies to provide extra fuel when in boost. None are cheap.
You really should have a Wideband O2 sensor AFR meter/gauge to watch for lean AFR.
There really is more to SC'ing any engine than just bolting it on. Without any fuel and timing management, your engine will blow, no matter how little boost you use.
There are many good books on supercharging. All are a great investment in knowledge. Most are on amazon.
AEM F/IC model 30-1913 (the dodge SRT4 one). This unit will allow you to retard timing for boost at a variable rate. Say you want more retard at higher boost pressures, it can do that. It will allow you to run bigger injectors (without a rising rate fuel pressure regulator return system). It does this by allowing you to add or subtract fuel by changing pulse duration. It also allows for O2 sensor bias, meaning you can change your afr in closed loop as you transition into boost. There are long distance tuners out there PM me for info about that. This tuner will let you pass an obd1 or 2 test. It will fail you for visual inspection. I don't have inspection in CT but still made a patch harness.
Afr and boost gauges are absolutely a requirement as is an obd2 reader of some kind with live data view. No one sells just the intake manifold. It would be nice if someone did... but you are on your own if you choose to fabricate your own intake. I did with some aluminum blocks off eBay. If you plan to top mount the m90 on the intake you will need to cut a hole in your hood.
Okay have been super busy lately with work and my harmonic balancer going out of commission but that is all fixed now. I removed all of my AC system besides the compressor which freed up a ton of space in the engine bay.
Also, I have been looking at various tuning modules and came across these 2 units which I dont know which is better.
The first one controls an axillary injector.
The second one modifies the MAP signal for use with 6 bigger injectors to turn them down for when not in boost.
The first one controls an axillary injector.
The second one modifies the MAP signal for use with 6 bigger injectors to turn them down for when not in boost.
You think the second one would work best since i am using the neon 703s?
05-15-2016, 03:17 PM
Junkyard Supercharger Project
