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LordBear
05-30-2009, 12:38 PM
hello all..i have kinda been going back and fourth on this and have searched the forums a few times..but not really found what im looking for..

i have owned one sc and sadly had to sell it..but plan on getting another one hopefully in the near future.. any how... i plan on getting the motor rebuild and getting the mpx package that has everything pretty much with it.. what i am curious about is a few small things.. reliability, durability, fuel milage, etc.. it is going to be mostly a dayly driver.. doubt i will ever go to a track..but if i do, it wldnt be more than a couple of times at most...

the scs get good fuel milage..so i was wondering if you killed that with the new set up. and then on the over drives for pullys are those really a good idea or not? i have read around and it seems those seem to be hard on the motor..i dont know.. i really luv the sc i just want to get it up to 300 or so hp... 350 wld be cool..but im not pushing for that..

i want it to be able to drive 4-5 hrs if needed...

QuickMustang
05-30-2009, 01:00 PM
I would avoid the MPX overdriven in the 25% range if you want a daily driver to be dependable. I'm not saying it can't be done, but more often than not, you end up with problems. Get a good ported late model blower, ported heads, a good cam, 10% -15% overdrive, a good intake system and exhaust and you should be able to get close to 300 hp without the abuse, reliability problems that could come with a full MPX set up...Now heres the disclaimer, I've never had an MPX, but I've read about quite a few problems with them, so others will be more knowledgable in this...

LukewarmSteak
05-30-2009, 01:09 PM
you want to have a 350 hp car with the fuel mileage of a stock sc??

LordBear
05-30-2009, 01:14 PM
obviously not...im just asking questions.... sheesh

fturner
05-30-2009, 01:46 PM
Please explain why a 350rwhp sc can't get the gas mileage of a stock sc or better other than being heavy footed. I'm talking just cruising around like normal.

Fraser

Mike8675309
05-30-2009, 03:04 PM
what i am curious about is a few small things.. reliability, durability, fuel milage, etc.. it is going to be mostly a dayly driver.. doubt i will ever go to a track..but if i do, it wldnt be more than a couple of times at most...

If I do an MPX housing I'll be making sure I have a good rotor pack. I'd get things adjusted so that max boost of 18psi or so (don't race to over 20) arrives at the maximum RPM you are willing to drive. That'll be for your once and a great while road attacks. Driving around, daily stuff on the highway is then going to be around 12-15psi which is nice and reliable boost, should keep heat down.

Fuel economy will be directly related to how often you run under boost vs vacuum. Keep the engine into closed loop and you'll see the best economy. To support the higher boost you'll need bigger injectors, and a different engine tune. Both will use up fuel faster than stock when you have go pedal because you'll be making more power.

If you just want to improve the performance of you car a little, have a little more fun with it, you don't need a MPX housing. There are many things you can do that will have your car feeling faster, and get you close to 300rwhp, that don't require anything other than a good M90 (94/95, s-port).

LordBear
05-31-2009, 11:09 PM
any other ideas advice or other info from any one who knows bout the mpx??

XxSlowpokexX
06-01-2009, 12:52 AM
THE MPX is made to spin. Id say an S port(ported 94-95) blower is probably better for everyday driving..For max power perhaps an mpx..But the extra RPM teh MPX needs probably means reduced lifespan over time

90blkbrd
06-01-2009, 09:09 AM
you want to have a 350 hp car with the fuel mileage of a stock sc??

I have a 350 hp SC and on the open road on a long trip I've had a bunch of 22 mpg, a few 23 and 24 mpg tanks. I've daily driven it and if I can keep my foot out of it, I can get 19-20 mpg.


THE MPX is made to spin. Id say an S port(ported 94-95) blower is probably better for everyday driving..For max power perhaps an mpx..But the extra RPM teh MPX needs probably means reduced lifespan over time

It may be made to spin but you don't have to. I guess I'd like to see a car on the dyno with a s-port and then an MPx with the same OD. I don't think a s-port would out perform a MPx at 15% OD.

It's hard to find a good used s-port or late model supercharger. So if you want to upgrade right away, I don't see why anyone, even if running stock OD can't have a MPx on their car.

Please note that the MPx shouldn't be driven in very cold temperatures, the clearances are to tight.

XxSlowpokexX
06-01-2009, 10:53 AM
I didnt run my S port at 15%. From the testing or numbers I have seen of people swapping from one to the other(MPII to MPX) at anything but high OD there wasnt a worthwhile improvement if anything at all. Perhaps someone will chime in. I cant off the top of my head remember the people exactly but Dave N seems to ring a bell.

XR7 Dave
06-01-2009, 12:09 PM
I think I'll stay out of this. :)

David Neibert
06-01-2009, 12:24 PM
I didnt run my S port at 15%. From the testing or numbers I have seen of people swapping from one to the other(MPII to MPX) at anything but high OD there wasnt a worthwhile improvement if anything at all. Perhaps someone will chime in. I cant off the top of my head remember the people exactly but Dave N seems to ring a bell.

Damon,

I never had an MPX...had an MPIII with ESM rebuilt and coated rotor pack, but never resolved my belt slip issues before switching to the AR blower. I made 356 rwhp at roughly 23% OD with slipping belts. Probably could have made another 15-20 rwhp if I installed the MP 10% crank pulley and upgraded tensioner springs.

David

kws6000
06-01-2009, 01:58 PM
I think I'll stay out of this. :)

Cmon Dave,your opinion is always welcome!

Toms-SC
06-01-2009, 02:13 PM
Find a used S-Port or even a MPII. Especially if reliability is a concern of yours.

There has been many vocal documented cases of MPX failures. However, there has been many documented cases of success. It comes down to taking your $1xxx dollars and asking yourself 'are you feeling lucky?'.

90blkbrd
06-01-2009, 03:02 PM
Find a used S-Port or even a MPII. Especially if reliability is a concern of yours.

There has been many vocal documented cases of MPX failures. However, there has been many documented cases of success. It comes down to taking your $1xxx dollars and asking yourself 'are you feeling lucky?'.

Name one MPx that failed that was doing less that 25% OD. I've heard vocally of a few MPII an MPIII failing as well.

I'm going to generalize here. If you are looking for around 300 rwhp and can find a used s-port or a properly ported 94-95, get it by all means. If you can't, a MPx will do the job and be just as reliable. But if you decide to max out the MPx and go 25% OD or more, the cards to look to be not in your favor.

Any of these blowers are only as good as the rotor pack in them. Whether or not it is a 89-93, 94-95, s-port, MPI, MPIII, or MPx.

90MN12
06-01-2009, 03:23 PM
someone correct me if wrong, but didn't even Kevin L back off the OD and do some better #'s w/ his mpx?

kws6000
06-01-2009, 03:28 PM
Name one MPx that failed that was doing less that 25% OD. I've heard vocally of a few MPII an MPIII failing as well.

I'm going to generalize here. If you are looking for around 300 rwhp and can find a used s-port or a properly ported 94-95, get it by all means. If you can't, a MPx will do the job and be just as reliable. But if you decide to max out the MPx and go 25% OD or more, the cards to look to be not in your favor.

Any of these blowers are only as good as the rotor pack in them. Whether or not it is a 89-93, 94-95, s-port, MPI, MPIII, or MPx.

How would an mpx be just as reliable if you have to spin it a lot faster to make the same boost as a 94-95 blower?...

If you spin it slower to maintain its reliability then you make less power than the 94-95 blower spun at a comparable speed.,and you defeat the purpose of having the mpx since you arent operating it in its zone of efficiency.

90blkbrd
06-01-2009, 03:46 PM
How would an mpx be just as reliable if you have to spin it a lot faster to make the same boost as a 94-95 blower?...


I never said spin it faster.


If you spin it slower to maintain its reliability then you make less power than the 94-95 blower

I must have missed that information, I don't believe this to be true.


you defeat the purpose of having the mpx since you arent operating it in its zone of efficiency.

I was merely stating if he couldn't get his hands on a good ported 94-95 or a s-port there is NO reason why he couldn't get a MPx to fill his blower needs.

You must have missed that a MPx at 15% od won the "Most HP with a M90" at the 2008 shootout. :D

chadder1313
06-01-2009, 03:51 PM
I'm currently running the MPX and have been pleased with the reliability of it. Now on the same hand I've had an MPIII fail. The one thing I've found that really effects the lifespan of these units is the quality of parts you use when assembling. I.E. rotor packs, snouts, etc. If you use parts that are in great shape, you shall be fine. On the other hand if you use parts with 150k miles then your probably going to experience problems.

DriftingThunder
06-01-2009, 04:35 PM
I've been kinda scared of the MPx. I am in the process of installing mine now actually and about a year ago I was planning on 25% OD but I think we might be on the right track with the front plate bearings not being up for that. Especially if we're spinning our motors past 6,000.

All that being said, I'm just going to see what it does for my car at 15% OD. The rotor pack I'm using supposedly only has around 30k miles on it. I bought the extra m90 from a friend's dad who had it sitting in his garage for many years and he claimed it was pulled off of a car at a shop and replaced without reason (sounds true enough, sadly...) When I assembled the MPx, the rotors and snout had a lot of dust and grime built up on them but they cleaned up very nice, and I have to say it seemed to be in very good condition. I took my current m90 off the car last night and wow, I don't know how much longer it was going to last, there is so much rotational play in the shaft! But it is much easier to spin by hand than the MPx. I'm not sure if that is normal? I have not the tools to check clearances myself either but everything looks good.

On a quick side note, the rotors in the m90 I took off of my car were coated, but the coating was partly flaked off. It was at 10% OD, I thought the teflon coating could generally withstand that?

At any rate, I have faith in the MPx case, and agree it isn't the cause of the failures.

kws6000
06-01-2009, 04:48 PM
I never said spin it faster.



I must have missed that information, I don't believe this to be true.



I was merely stating if he couldn't get his hands on a good ported 94-95 or a s-port there is NO reason why he couldn't get a MPx to fill his blower needs.

You must have missed that a MPx at 15% od won the "Most HP with a M90" at the 2008 shootout. :D

Basing my comments on the 2 SCs in the family...with very similar bolt ons stock 95 blower with '89 pulley produced essentially same boost as mp3 car with approx 14%od...

My understanding is that mpx/mp3 blowers are essentially the same efficiency with the same od....Getting the mp series blower and not going with a large amount of od,ie 25% isnt going to work very well,...and if you spin it that fast you take your chance of premature failure since you are spinning it much faster than its design limitations for reliability.

90blkbrd
06-01-2009, 05:07 PM
Basing my comments on the 2 SCs in the family...with very similar bolt ons stock 95 blower with '89 pulley produced essentially same boost as mp3 car with approx 14%od...

Boost is irrelevant, when comparing 2 cars. Swapping the 2 blowers and see what happens.



My understanding is that mpx/mp3 blowers are essentially the same efficiency with the same od

There may be differences in blower PSI thoughout the rpm band, but I believe the AIT will always be lower on a MPx. So even if the PSI was identical in this hypothetical test, it should net better results.

All I am trying to say is if he wants a MPx or can't get his hands on a good used Eaton. The only downside to a MPx is the price.

How do you know a s-port or 94-95 wouldn't seize at 25% od at the same or higher rate than a MPx?

chadder1313
06-01-2009, 05:32 PM
How do you know a s-port or 94-95 wouldn't seize at 25% od at the same or higher rate than a MPx?

Very true! Thats a good question!

kws6000
06-01-2009, 05:38 PM
Boost is irrelevant, when comparing 2 cars. Swapping the 2 blowers and see what happens.




There may be differences in blower PSI thoughout the rpm band, but I believe the AIT will always be lower on a MPx. So even if the PSI was identical in this hypothetical test, it should net better results.

All I am trying to say is if he wants a MPx or can't get his hands on a good used Eaton. The only downside to a MPx is the price.

How do you know a s-port or 94-95 wouldn't seize at 25% od at the same or higher rate than a MPx?


actually boost is relevant when you have 2 cars with essentially the same mods with stock long blocks...there isnt going to be much inter car variability other than the blowers

kws6000
06-01-2009, 05:39 PM
Very true! Thats a good question!

Of course it would also have a high failure rate at 25% od...why would you expect otherwise/

LordBear
06-01-2009, 06:39 PM
ok..this is what i was thinking... maybe getting a motor built from s&s out of spokane?? need to check them out more first... or having the motor built at aldredge i think is how it is spelled in portland oregon and having them do all the work as far as building setting up the blower and chipping it and all.. sence they are suposed to be the local experts on the sc's.. and i was thinking bout getting the full blown mpx kit with the fmic and the 10 rib and all and of course the new sencers and stuff..and probly that new um piece that goes behind the bumpers somwher to increase the air flow throw the ic and radiator...and also getting a larger radiator.....i dont drive a whole lot and dont plan on taking it to the track..although some day i might..but doubt it...and like any one else play a little bit...lol.... but if i decide to hop in and drive the 4.5 hrs to portland once in a while and back...want to make sure its not going to blow on me..

XxSlowpokexX
06-01-2009, 06:42 PM
It will help if people chime in that have run the MPX and have had issues or even none at all. From my understanding (and I could be wrong) the MPX due to the inlet shape needs to be spun faster to create sim boost as lets say an mpII. As far as rotor packs unless you are buying new they are either rebuilt($400), used?????? or r new $$$$$$$$. This brings up the cost substantially for reliability sakes. You can get an S port and still run it at reasonable OD's and it wil last..And produce good numbers. Easy 300-350 from what Ive seen with not much work or OD.

About 8 years ago I had ESM port and modify a 94 blower and MP inlet to mak eit what they called a DIII. Looked very sim to an MPX/MPIII and I had to OD it to make more boost as well...I was making 21 PSI with that particular blower. It also has stiffeners welded on the side as they had shown case distortion at higher boost levels as well. It held up fine before I tore the car apart. I may have been doing 15% OD..Cant recall

And for the record I do own an MPX but am using it on a v8 car...not a v6 which does rev higher and needs as much air movement as possible.

So teh question is ..Is it work it...

To me no. Tally up the costs to run an MPX properly that will hold up and its not worth it to me. Id say between the pulleys for OD, rebuilt rotor pack, MP tensioner springs, case and inlet, rebuilt snout... your talking big $$$$$..

Meanwhile a 94-95 blower(even rebuilt) with a mild S port, MP inlet, 10% OD will give most what they need and is a GREAT improvement over a stock 89-93 blower...Its also allot cheaper.

Use the search button and you will find peoples experiences with the MPX.

Basically if you are looking to squeeze every ounce out of your motor and willing to give a little to get a little..Go for the MPX. But the money is best spent elswhere IMO

chadder1313
06-01-2009, 06:43 PM
The reason for me stating this is because MPX's and MPIII's get a bad rap for failures around here. I would expect a early model, 94-95, s-port, MPII would fail in the same way the MPIII's, and MPX's do, if O.D. at the same 25 or 30%.

XxSlowpokexX
06-01-2009, 07:09 PM
I agree 100%..And would probably fail even worse..I can just imagine the heat generated spinning an M90 at those speeds!

rzimmerl
06-01-2009, 07:46 PM
I'll chime in also as I had an MPx last year but was sold to fund my Autorotor. I ran the MPx with 15% OD for about 3000 miles with no problems and many passes down the track at 17 psi, granted the rotor pack I had had less than 5K on it. This was with the MP 10 rib pulley kit also. This netted me about 290rwhp and 13.2@106 in the quarter on a stock long block.

Which brings me to this year, needing a blower to drive the car since the MPx was gone. I bought a used 94 blower off of Ebay with the stock inlet plenum for around 300. I was shocked when I received it as it had a Magnuson sticker on it meaning it had been completey rebuilt and a new rotor pack sometime not to long ago. So I tore it apart and gave it a decent not crazy port job, new rear rotor bearings, coupler, and reassembled with the stock plenum. Again running 15% OD (this time just using stock belts no fancy 10 rib setup and still no belt slip), the 94 blower could barely muster 14 psi and felt dog slow compared to the MPx. So I picked up a Magnum Powers high flow inlet plenum and another 5% OD bringing the OD to 20%. Huge difference the plenum and extra OD made. Gained 4 psi to about 18, then ran 13.1 @ 104 in the quarter.

The 2 blowers definately have a different feel to them. The 94 gets out of the hole like an animal but falls off towards the 4200 range. The MPx was a little sluggish out of the hole but once around 3000 it really woke up as is got in its range and was shown by my higher trap speed. It all depends on what your engine is setup for and what you want the car to feel like. Just my opinion, OK I'll stop blabbering now.

chadder1313
06-01-2009, 10:58 PM
The 13.02 i ran was on a ported 94-95 blower, stock inlet, stock injectors, stock intercooler. I have since had the MPX on along with many other upgrades, but have not been able to get it to the track. I will say the MPX is a real monster at 25% overdrive. It just pulls all the way up. Im gonna guess its closer to a low 12 now. I think its well worth the price tag considering the alternative which is more than double the cost of the MPX. On the other hand i would love a AR!:D

DriftingThunder
06-02-2009, 01:24 AM
Weird because I found the MPx to be a relatively inexpensive go-fast part.

chadder1313
06-02-2009, 07:51 AM
Weird because I found the MPx to be a relatively inexpensive go-fast part.

I agree 100%

nickleman60
06-02-2009, 08:01 AM
I have a home ported '94 blower, MP inlet and FMIC running 15% OD on my '89 along with other bolt-on mods and it runs pretty strong. I have a MPX running 25% OD with a ton of mods on my Black '94 and even with needing a tune it "sings" in the upper rpm range. It's hard to compare the two because they're such different animals. Neither car is a daily driver, I leave that to my basicaly stock '94 auto.

rzimmerl
06-02-2009, 05:10 PM
Weird because I found the MPx to be a relatively inexpensive go-fast part.


I'll agree to that also. Had it not been for finding the AR, I would have been running the MPx @25% this year with the heads and cam to see what it is really capable of.

LordBear
06-02-2009, 11:51 PM
doesnt sound like very few people have gotten the mpx..no wonder magnum is closeing things out.....hhmm not sure which direction to go now.

XxSlowpokexX
06-03-2009, 12:26 AM
I dont see the MPX as being an inexpensive go fast part. Id rather get heads and a cam at that price range.

Chadder..Besides th eblower swap and moe OD what have you done since swappin blowers?

DriftingThunder
06-03-2009, 06:28 AM
I dont see the MPX as being an inexpensive go fast part. Id rather get heads and a cam at that price range.

Well, me personally? I like both. Heads and cam, and blower upgrades. It's not like you can't have the combination, pending money. Comparing apples to oranges makes a very moot point. Now let's play apples to apples. The MPx is aggressively priced.

Just my $0.02.

LordBear
06-03-2009, 01:36 PM
hhmm ok..lets add this..im not worried bout the money part right now ..more of options and reliability... like waiting for xmas morning..the excitment and anticipation ..and u open the present and bam..there they toy u have been wanting for a long time..and 5 min later its buzted cuz it was a ~~~ and ur disapointed and now toyless again.... was thinking of putting $10,000 in to the car give or take few bucks..

90blkbrd
06-03-2009, 01:59 PM
heads
cam
headers
exhaust
under drive pulleys
If auto 3.73's and 2200-2500 stall torque converter
If 5-speed - leave alone for now
85 mm TB
85 mm MAF
3.5" CAI
Double IC with fan or Front Mount IC
somehow get your hands on a twin screw setup or ported 94-95, s-port, MPII, MPIII, or MPx with matching MP inlet
Overdrive pulleys for supercharger
Upgraded radiator
upgrade fuel pump
50-60 lbs injectors

and last but certainly not least and IMO most important: Dyno tune

LordBear
06-03-2009, 02:08 PM
ok..got all that already... what i am trying to find is the reliability issue.. these cars already have scs on them..but bad exhaust... so is the car going to be drivable with all this stuff done..or is it going to be a couple trips to town and boom...

DriftingThunder
06-03-2009, 02:43 PM
If you want to have fun with the car, but don't want to change your head gaskets in the relatively near future, exhaust is an excellent idea.

90blkbrd
06-03-2009, 02:45 PM
I pretty much have all of the mods I listed and my MPx has been overdriven 10% and for the last 6-7K at 15%. It's putting down 350 rwhp and 404 rwtq. I drive it daily as much as possible.

Except for a minor cold engine issue it runs like a champ with no problems.

chadder1313
06-03-2009, 04:53 PM
I dont see the MPX as being an inexpensive go fast part. Id rather get heads and a cam at that price range.

Chadder..Besides th eblower swap and moe OD what have you done since swappin blowers?

85mm TB, 60# Injectors, 80mm MAFS, Ken Wagner Double IC. My car has a really good converter. Thats my secret weopon.:) With the MPX it really feels like a monster. If and when i get it to the track i don't see it taking to many launchs off the line with slicks. Dave you should be getting a call in the near future;)

1989superhot
06-05-2009, 04:06 PM
what's the max od a 89 ported blower can run safely for the blower it's self

pablon2
06-05-2009, 04:44 PM
I am getting 15mpg with my MPx and 25% OD. I don't go into boost much as of late so I attribute much of the fuel efficiency or lack thereof to my cam. Running 60lb injectors doesn't help either as they seem to dump the fuel with the slightest push of the go pedal. ;)

DriftingThunder
06-06-2009, 12:03 AM
I am getting 15mpg with my MPx and 25% OD. I don't go into boost much as of late so I attribute much of the fuel efficiency or lack thereof to my cam. Running 60lb injectors doesn't help either as they seem to dump the fuel with the slightest push of the go pedal. ;)

Cams are a huge killer of gas mileage from my experience with LT1s and 302s.

LordBear
06-06-2009, 04:40 PM
i have been going back thru a ton of posts that mention mpx and got a ton more to go thru and running in to walls here...half of them absolutely luv the mpx and the other half are blowing up....and make it sound inpossible to get a good rotor pack for them..

CMac89
06-06-2009, 06:36 PM
How do you know a s-port or 94-95 wouldn't seize at 25% od at the same or higher rate than a MPx?

I ran 25% OD on my late model blower and nothing negative happened to it. It could have been a hand-me-down from Jesus, or something.

90MN12
06-06-2009, 07:16 PM
I ran 25% OD on my late model blower and nothing negative happened to it. IT COULD HAVE BEEN A HAND-ME-DOWN FROM JESUS, OR SOMETHING.
LOL. The blessed M90 or what?