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2K views 18 replies 8 participants last post by  s-cam 
#1 · (Edited)
Gents,

As you may or may not know car is in pieces getting a forged 402 motor built which according to our engine builder should easily take 20 to 30 lbs of boost without worry.

The mp112 will be going eventually (maybe a tvs in the future) but in the mean time the maggie is out for a few weeks so looking for any reasonably cheap and cheerful ideas as to what we can do to improve it.

Already running a 2.7 8 rib pulley (OD crank) so stepping down in pulleys and introducing belt slippage again is not on my plans.

From what I've seen on the mp112 people have swapped hosing, swapped rear pulleys (to what??). I even recall someone ported the maggie.

Any ideas or shall I just leave it be.

Just trying to save myself more mod hell down the road as everything is apart and out.

Cheers.

Nik
 
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#3 ·
Nik, when guyz say "swap the rear pulleys," they mean swap them with each other. Apparently, they're different diameters, and by swapping them, you gain (not lose) in rotational speed of the blower. Problem is, I don't know of anyone who's done it, certainly not in their garage nor any shop for that matter. Magnuson has done it in the past as I understand, but I'm not sure if they'll do it anymore. My guess is there were issues.

If I was you, I'd peddle your maggie as is to someone here and apply the cash to that TVS. :thumbsup:


JD03Cobra might be interested. :stirpot:
 
#4 ·
That ported Maggie got stolen :crybaby: He's lucky he got it back :)

Did not know that. I always thought they made the rear pulleys the same size. If all you need to do is switch them around, have your mechanic look at it. A puller and a press should do the trick. Can't get any cheaper than that :thumbsup: and I would assume it'll push at least 2-3#s more boost on a stock motor. I would also assume you'll be maxing out (or damn close) the Maggie,,,be careful.

More info on the housing swap please.

IF you can swing it, deff upgrade to another blower now. Better/cheaper in the long run. But I know you've been dumping a ton of $$$ into the car......
 
#5 ·
I would do what Randy said. Sell it to defray the cost of a new, bigger, better, unit. At this point in time, you have a little unit. Do you want a little unit?:duck::histeric: I think not! Go for the bigger, better, deal. :D
You could make a phone call to Magnuson. Maybe you could 'trade it in' on a rebuilt bigger unit.
 
#6 ·
Thanks for the feedback gents. Little one trying to push into a big... erm.. ok shall end it there.

I'll have a look at the rear pulleys. Seems like a cheap and cheerful trick if they are different (honestly I hadn't noticed). What are the max tolerances on the mp112. I think nose pulley was 19,000 rpm, and max boost was 12 or 15 psi but I don't recall the specifics..
 
#7 ·
Thanks for the feedback gents. Little one trying to push into a big... erm.. ok shall end it there.

I'll have a look at the rear pulleys. Seems like a cheap and cheerful trick if they are different (honestly I hadn't noticed). What are the max tolerances on the mp112. I think nose pulley was 19,000 rpm, and max boost was 12 or 15 psi but I don't recall the specifics..
 
#8 ·
Whether it was Magnuson just saying they didn't recommend doing it to keep their reputation in good shape (because of "issues") or whether it truly is tricky and could result in damage (i.e. "issues"), be careful with that rear pulley swap.

I like heavy's idea of the 122, too. That or the TVS route.
 
#9 ·
If I'm going down the route of swapping the s/charger I'll go all the way with a tvs 2300 if we can cram it in there. No sense in small steps here. Thanks for the heads up. We can probably pry the rears off. I'm assuming the idea is to overdrive the main rear drive pulley. I've yet to find a discussion on the topic from anyone that's done this.

I'm still interested in a pic of the serpentine belt routing of anyone who has an 8rib OD setup as I'm really not liking the way we routed the belt initially i.e. not really wrapping the s/c pulley.
 
#10 ·
Ill try and get a pic of mine for you. My blower was the one that was supposed to be ported, the guy stole it, he went to jail and had everything he owns seized, and I got my blower back. (don't mess with a cops son lol) it never was ported. The rears may be able to be swapped but it will be close. I loomed at it when I had my Maggie off and i don't think it will work but I didn't measure anything. I think you will have some clearance issues with the bigger pulley on the jackshaft.
 
#11 ·
THanks. I just need a pic of the pulleys/serpentine belt on the 8rib from front/above.
 
#12 ·
Sorry I was going to get one today for you but I had a minor fender bender on my way home from work and forgot all about it. Looks like I need a passengers side headlight and fender now.
 
#15 ·
Saw the pics. Do you recall off top of your head what size serpentine belt you used?

And thanks Twitch for the linkage.
 
#13 ·
I was in the same boat - I am building a 416 cu LS3 with et performance heads etc etc. I have a 112 that is ported with the underdrive ratio (.83) on the back and a 2.5 on the front that i ran on the stock motor but with all the research I did I upgraded to a 122 with the overdrive system on the back (1.17). I talked with magnusson and got the run around about putting a 2300 on it so I went with the easy choice and found a good deal on a 122 and upgraded to a 90mm throttlebody. I dont have the motor together yet but i feel far more comfortable with the 122 then with the 112.
 
#16 ·
Where did you find a 122 for a good price that fits our cars?
 
#14 ·
#17 ·
I believe it had a 102 5/8" belt. I'm having issues with the belt all of this sudden though. Not sure what the deal is but The just start to squawk and then they self destruct. I think I need a new tensioner too.
 
#18 ·
Well I guess it's just not my luck this week. Just left the body shop getting on the highway and I broke something in the rear end. Car tries to go but makes a lot of clacking from the rear. Doesn't look broke, no fluid on the ground, both axles are still in and togerther. I'll know a little more when I get home. Sorry no pics tonight either lol
 
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