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I am having a magnuson installed next week. It's going on a new R/T that is stock except for catbacks and mopar CAI. The installer says he can modify the CAI to use with maggie. I asked him about the recommended boost range on a stock 5.7 and he said 4-6 pounds. I had expected him to say 6-8 pounds. My goal was to settle in at around 7 pounds max boost.

Does anyone disagree with his suggested boost level? Also, what determines boost? Pulley size, or something else? I am just curious as to how the boost range is set during the install.
 

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The stock boost level from magnuson should be fine. It's a 6 psi kit, but it's an estimate. Go with the stock kit. As for the MOPAR CAI conversion, Speedy did his and it looks good. Should be a good thing feeding the maggie. Are you getting an air fuel ratio (AFR) or boost gauge installed? I'd recommend the AFR gauge if you can manage one. Good to know if it's running the right amount of air to fuel. Don't want it too lean (too little fuel) in a boosted application. Stock magnuson tune should be a problem since it's conservative but it's good to know as weather can have a significant impact.

HemiSam
 

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Discussion Starter #4
Thanks, Sam. I hadn't thought about AFR guage. Is that a top-of-the-dash-mount?

It's good to know the Mopar CAI can work well with a blown engine. I ordered it before I realized my wife would have a weak moment and allow me to supercharge it. I wonder how she's going to feel in february when we are burning ccouches to keep the house warm?
 

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Haha, burning couches good one.

The Mopar CAI fits pretty easy with some slight modification. The tube has to be cut down and you'll need an adapter. Don't let the shop charge you too much to do it.

That WILL require a tune update though. The blower definitely likes the air. I gained about 20RWHP adding it to mine.

I've got info on how to do it on my site.

 

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Thanks, Sam. I hadn't thought about AFR guage. Is that a top-of-the-dash-mount?

It's good to know the Mopar CAI can work well with a blown engine. I ordered it before I realized my wife would have a weak moment and allow me to supercharge it. I wonder how she's going to feel in february when we are burning ccouches to keep the house warm?
Take a look at Speedy's site and see if you can get the CAI installed along with the Maggie so you know your tune is good to go. With the stock tune, you should be fine since it's pretty darn conservative for obvious reasons. toofart did this so you can reach out to him to see if any tune adj was req'd. He's up North so he'll be a good point of reference...gets leaner when it's cool.

Suggest for gauge pods you look at A-pillar pods like the Razor's Edge I run and Speedy runs. It's great in that your gauges don't block your view of the road but they're right there when you need to look. Some don't like them, but I think they look clean and are really functional. Some are stuck on needing them to be in the dash (nowhere to go really) or on top of the dash since it was that way back in the day... To each his own.

HemiSam
 
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The 'Stock' Magnacharger tune is conservative, which is not a bad thing. Zero KR and AFR in the high 10s. I gained over 30hp by adding a high-flow filter, and my AFR went up to 11.3.

 

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I have a Maggie with the canned Magnuson tune...getting ready to install my K&N cold air intake. A few questions....should I be concerned with leaning things out without getting a custom tune? How about switching to a 180 degree thermostat? Thoughts from those who have done it? Also...anyone know how to read Air/Fuel ratio with the Predator under live data?
 

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the 180 t-stat is zero risk as long as it's installed properly. Bunch of how-to threads here. If you get a good unit, like the Motorad (JET 180), you'll see a small pin at the top of the unit under one of the end of the curved bar/overlap at the top of the unit. Just make sure it's at 12 o-clock when you install the unit. It's a safety relief and needs to be at the top.

You can't record actual AFR with the Predator. You can with the Trinity but only if you have a wideband / O2 sensor that has an analog output that you then hook into the Trinity using a 2.5mm stereo jack and a formulaic conversion of the output from 0-5v to the AFR readings....sounds harder than it is but that's the only way to do it with a DiabloSport product that I'm aware of. Easier is getting the wideband/O2 sensor and a dedicated gauge and watching what it is with both the canned Magnuson tune (preferably low 11's) and then any adj's from custom tuning thereafter. If you go to a good tuner, mull around here and you'll see who they are (e.g. AJ "hemituner") you'll be good to go. If you live in a clime that gets cold, you may want a cold weather tune as boost will rise and your AFR will rise with the air density...it's a reality.

The K&N drop-in is also a non-issue. Just do it. You'd be better off with a larger CAI than the stocker, or modifying the stocker airbox for a bigger opening. Some good threads here and on the LX forum.

Good luck.

HemiSam
 

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Thanks for the good advice! I just put in my boost gauge and it's right at 7 lbs. I talked to a tuner here in San Diego that says that a custom tune will be a lot better than the canned tune from Magnuson and I won't be running so rich like their set-up is. They said it would be about 2 hours of tuning and cost $420. Not just wide open throttle runs, but also different RPM ranges to get things dialed in. I just am a little hesitant without getting a referal to some I KNOW will run it good but SAFE. Wonder who else in the San Diego might have experience with Hemi's running Magnusons? A lot to gain, but a heck of a lot to lose if they don't make it safe is what concerns me
 

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I'm assuming you're on a stock bottom so you're going to need to keep it fairly conservative for longevity. I'd suggest reaching out to Cam and Adam at Spankin' Time for starters.

A boost gauge is fun and interesting...I've got one, but it doesn't hold a candle to a good wideband/O2 sensor and gauge. That's what's really important. You don't want to have a lean, part throttle boost or high boost condition...period. Just my two bits.

Good luck.

HemiSam
 

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Im trying to understand a little bit more than the basics...so if I am running a bit lean, will I tend to get detonation which will in turn cause knock retard to kick in? On the predator, is it the NK FUEL RE, NK LT RETA, & NK ST RETA that will change from 0 during detonation?
 

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Running lean in a boosted applications...not good. Detonation = risk of piston failure, especially with the stocker equipment. ST KR (short term knock)...a bit isn't a big deal IMO, but you don't want to be seeing a lot of it (I don't get too excited about 1 or 2 but when you're seeing 3-4 regularly you've either got a fuel or tune issue). LT KR (long term knock) not good at all. You don't want to see any of this. Knock retard is basically the computer stepping in to protect the motor and affecting your tune...pulls timing as an example.

It's useful to periodically datalog the car under different scenarios (e.g. cruising, then a WOT, etc...). Separate and note those logs so you know what is what. If you're tracking vehicle speed, rpm and actual spark cylinder 1 you'll have a pretty good idea whats going on. Also, MAP and barometric pressure (or Pratio) well let you back into your boost level. Oh yeah, throttle position sensor is useful. This is basic stuff. Go out on DS website forum area for good tips.

HemiSam
 

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Whooo Sammy....turning in to a regular tuner type...good info.

I'll add that LT KR is the computer stepping in and removing timing even if there is no actual knock present. It's preemptive and is why it's so bad to have. It robs the car of power even if it really wasn't necessary. It makes this determination based on when it sees ST KR in the same area over and over.

Lean makes a bit more power, but the side effect is a lot more heat. Heat means volatility, and volatility and that leads to an increase chance of knock which is BAD on the pistons. The increased heat will also expand the rings more and if the ring gap closes and has nowhere left to expand it will want to bend up and pops the edge of the piston off and it's game over.

Bottom line, on a stock motor you don't want to be more than about 11.2 - 11.5 AFR. That's a good safe AFR to run and will provide a nice compromise of good power and safety.
 

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Yes and it's basically a measure of the knock your sensors are reading and responding to. If your motor is forged, sometimes the sensors not knowing the engine may be a bit noisier will pick up false knock but I wouldn't assume this. Can be dangerous...

HemiSam
 
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