I have mounted a little roots supercharger to the front of my 998 motor it than goes through a front mount intercooler and into the back of my 1 1/2 inch su ,the best i can get is for it to idle (most of the boost is bypassed through a blow of valve) the motor will stall on any load, ive tried a metro turbo needle and spring and now have lost idle ,dont want to spend big money on metro turbo carb if i dont need to, any help would be great

you need a turbo carbi
the standard is no good for this application as the positive charge dose something to the carb and you get the hassles unless you do it suck through
makka

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Anonymous moderation means the agro that is built up towards the mods isn't aimed at an individual (fewer "Makk" attacks). Less stress for mods means less moderator "retirements".

Your Problem is that the blower is producing enough pressure to blow the fuel back down the Jet... Lean running - not nice....

Ok you CAN modify a 1 1/2 for Boost.... but how handy are you with Carbs ?

You need to

Add a Plenum (best size would be about 1.5x engine capacity so in your case about 1.5 litres should do it.. this is NOT critical, but good for a couple of extra Horsies...)

Add a restricter to the mouth of the carb (1/8" should do) you want to raise the pressure in the plenum higher than the carb throat.

Pressurise the float bowl - take a line from the plenum - this ensures that the fuel in the Jet is at a higher pressure than your carb throat - this is what you are NOT experiencing right now....

Add "Rising Rate Pressure" to your fuel delivery system, your float bowl should ALWAYS see at least 3 PSI MORE than your Carb throat...this ensures that fuel will flow INTO the float bowl

Seal the Throttle Shafts - not sure how you are going to do this one, but i HAVE seen Holley 4BBL carbs "Boxed" so that the entire carb is pressurised so that the pressure inside is equal to the pressure outside and thus, no leaks.


So in short, a HIF-6 and Plenum from a Metro Turbo would be Ideal, but yes, expensive... i got lucky, my carb came from an ex-racer in the states who sent it to me for next to nothing... sure i had to replace every O Ring and seal, but hey, it was cheap ! (Still running 3 years later too !)

Good luck
J

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Thanks heaps i got a pressure regulator last night, im not sure if the electric pump i have is up to the job do you now roughly the range of pressure your car runs between

i was thinking get one of theose su float bowl lids with the dual entry run one a fuel line and one a line from the plenium , or some other way to pressurise the float.

with the regulator it has to be a rising rate one or ask kazjim i think he modded his to a rising rate? and as he said fuel pressure has to be 3~4 psi above boost. Most electric fuel pumps on minis are 3~4psi so you will need a high pressure pump too, depending on boost running.

i think this should work even with the hs4 the way it is but you would probally be better of with a turbo carb and plenium

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1152cc turbo A-series now with 125.7hp at the wheels !

AUSSIE Turbo mini forum >> http://boostmini.justboard.net/

https://www.facebook.com/boostmini

Well, when i was speccing my fuel system out, i knew i needed pressure... heaps of pressure... but not EFI type pressure (60+PSI!!)

The only one that fit my needs was the Holley Blue... un-regulated it will do 19PSI all day, or a mild tweak will see it doing 25Psi with no hassles...

I think the red will do about 12Psi (leaves you with headroom to run about 8Psi boost...)

J

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I GOT THE MINI RUNING ON THE WEEKEND IT STILL NEEDS A GOOD TUNE, SO ITS GOING ON THE DYNO THIS WEEK, I WILL POST THE POWER FIGURES

ON THE FIRST RUN I FORGOT TO BLOCK THE HOSE BETWEEN THE ROCKER COVER AND SU, SO IT PRESSURISED THE BLOCK AND BLEW THE DIP STICK OUT "VERY MESSY"

THANKS FOR THE FUEL PRESSURE TIPS 'I USED A PUMP OF MY OLD RX7 THAT FLOWED 200 HP AND THAT DID THE TRICK'

This sounds exactly like something I would like to do! If you had the time and inclination a how-to would be terrific

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Noli Illegitimi Carborundum

when its all working well, i will post pics of the super charger bracket, piping and other mods i did to get it working. it shouldnt cost any more than $500 inc blower for others to do this conversion

+ A strong motor, mine has been rebuilt not that long ago

hot stuff, that's $500 I'd spend any day!

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Noli Illegitimi Carborundum

so why are you selling it now?
how did it go on the dyno etc.?

the blower was just for fun while i was doing the daihatsu conversion, I planned the daihatsu conversion to take about 3 months but it is easier to fit than i thought and should be ready to pull the "a series" out at the end of the month it probably wont go as fast but i want reliability

The problem when it wasnt running properly was the fuel reg, i Had buy a malpassi and it cost $180 so i had no change for the dyno run and am now spending money on the conversion instead