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Frustrated with my MPI stage one kit

F

Fordman

Newbie
Joined
Jan 28, 2006
Messages
19
Location
NB Washington
Set up in the 240 hp/ 10psi boost mode with the pulley.... Kept blowing the throttle bodies off.

So I put on a boost gauge... glued the boots onto the case and tried it out this morning... Boost gauge was buried at 2/3 throttle... then the boots blew off again. Why would I be at 17+ pounds of boost? it's only supposed to go to 10? This kit has been nothing but headaches for me from the start. Any dealers in Washington that have experience installing this kit that can fix this issue? :o| :o| :o| :o| :o| :o|
 

Really shouldn't be blowing the TB's off at all. Im running 10 psi right now and have zero probs at all with anything to do with keeping the IC or TB's on the sled. Can you take some pics for us of the belts etc and pulleys and the throttle bodies?
 
My throttle bodies blew off the head the first time I rode mine. Upon inspection it looked as though there was some sort of silicone type spray from the factory on them. I removed all four, cleaned them with brakleen, which made them tacky, and reinstalled them. Haven’t come off since. I also removed all the intercooler and charge air tube hoses, cleaned them with 409 rinsed with warm water, which made them tacky, and reinstalled. Haven’t come off since. Note that 10,000 engine rpm (150,000 compressor rpm) is the MAX engine rpm you should run with the overdrive pulleys on the stage-1. Since boost is directly related to engine rpm and your local air density on the SC, letting the engine overrev also overrevs the compressor, which exceeds the intended design parameters, this creates high intake temps and a heat soaked intercooler (bad things can/will happen). When the throttle plates are at part throttle it restricts the flow increasing the boost reading at the intercooler. If you T your boost gauge into the engine side of the throttle bodies your gauge will read what the engine is seeing. To get any sort of accurate reading when your boost gauge is connected to the intercooler your engine must be under load in a steady state wide open throttle position. Throttle plate transitions (opening and closing) will skew any readings taken from the intercooler.
 
Fordman-I think Hammer has the right idea-I've buried my 15 psi gauge(at the intercooler) with 26-22 and with 26-24 sprockets under certain conditions-call MPI(try to get Mac)they will help-I blew the intercooler off mine 3 times in -5F weather--it will get better,this weekend was all riding no wrenching!!


Good Luck
 
Well, it sounds like I've got a few things to look at. Part of my problem is that this is all new to me so it takes some time to absorb all of the info.

I'll call MPI tomorrow to get their take on it as well and go from there. I'm watching my season slip away....
 
Also a trick we use on the street cars with turbo's etc and big intercoolers is to spray the connections with hair spray then shove them togeather its basically good luck getting them apart afterwards. The spray acts like a lube to assemble then drives and grabs silicone couplers like no tomorrow. :Rockon:
 
I also ground the spacers on the carb boots down to 1/2 there size for a better clamping. Then brake kleen and hair spray. Get it going i would like to see that supercharger go. I am just north of you in Marysville.
 
Do you have a boost gauge on yours? and where is it connected and what does it hit when you ride?

I just put an automotive boost gauge on it and I hit 18psi running across a grass field. I suspect that I may have a bad SC. Talked to MPI this morning and they'll send me a new one but wanted to see what PSI I was running.

I'm pretty confident that contact cement works on the boots if it was running 10psi.

I'll wait to see what happens then.

I can say this... before I blew the boots off.....Wow...what a ride.
 
Fordman said:
Do you have a boost gauge on yours? and where is it connected and what does it hit when you ride?

I just put an automotive boost gauge on it and I hit 18psi running across a grass field. I suspect that I may have a bad SC. Talked to MPI this morning and they'll send me a new one but wanted to see what PSI I was running.

I'm pretty confident that contact cement works on the boots if it was running 10psi.

I'll wait to see what happens then.

I can say this... before I blew the boots off.....Wow...what a ride.
Click to expand...

I run an autometer pro comp boost gauge its the only one other then digital that seems to survive on a sled.
 
I rode an MPI APEX in Island Park and it was a blast. At the end of a long day of riding was trail riding back and decided to see what WOT was like in the trail - the sled was overreving and it also blew the intercooler off the head - I can see that it's pretty tigth to assemble and the engaugement on the head it less than 10mm...

I thought the sled ran good with the poor clutching we had in it and wold condsider this as a possible next sled.

On an apex at 11K with the big pulleys - what PSI should be expected?
 
mine blew off 3 times
throttle bodies 2 times
what a b----
removed spacers in clamps and cleaned
still blew off
engine blew up 14 psi a stock comp
rebuilt with 10:1 pistons and 12 pounds
hd head bolts/made brackets off rt head bolt
and left tensioner bolt and welded brackets to
side of intercooler,made a 3/16 rod with hook on the end ,threaded the end of rod and tightened rod too hold intercooler and throttle bodies on
worked great 900 miles @ 12 pounds and never
blew off
 
Do you run pump fuel with the 10-1 pistons at 12 psi. Also what elevation do you run at. Is that a stage 1 or 2 kit from MPI.
 
I have a MPI Stage II kit at 12 lbs. Blew the throttle body's out of the head the first time I hit it.
Removed and cleaned what I thought was lite oil and fuel looked like 2 stroke oil and gas. I used 3M 1300 adhesive on boots and removed the spacers on clamps so I could tightren just alittle more, don't think you need to over tighten. Havent had any problems since. :D
 
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