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Super Charger Build

Discussion in 'Performance' started by spaner, Jan 21, 2010.

  1. spaner

    spaner Well-Known Member

    Last edited: Mar 7, 2012
  2. Acerguy

    Acerguy Moderator Staff Member

    Awesome post, Spaner!!! This will be fun! :pop:

    WELDER Member

    I'll be watching, closely:cool: Here's a smily eating some popcorn for you :pop:
  4. miniMOG

    miniMOG Member

    I have a headache now!:eek:

    Good luck!
  5. o8k

    o8k Member

    What affect will this boost pressure have on the Carb? 7psi boost is also about 1.5x on how much fuel you can shove in there too. Air/fuel ratios need to be regulated on gas engines (diesels dont care about that stuff, but gass'ers do). all the extra air w/ no extra fuel means you will run really lean and hot right?

    I guess i figured you would also have to address getting more fuel into the mix here too. On a EFI system, its usually a ECU flash of some kind. Im not a carb guy tho so i dont know how it all works for a carb engine. new Carb jets er somthing?

    Last edited: Jan 21, 2010
  6. o8k

    o8k Member

    I would also reccomend an intercooler to keep your thermals under control. Small vol intercooler for snappy power response, and a large vol intercooler for towing. The boost lag over the intercoooler is a function of the intercooler and piping volume. So you need to watch your "post boost" piping volume to tune the power response...

    I bet you will set off your bbq light on the dash too ;)
  7. o8k

    o8k Member

    On yet another note (sorry i keep thinking of stuff)... Non-asperated engines usually lower the compression to accomidate the extra forces exerted on the engine. Not entirely true if the engine is built from ground up w/ a turbo or super charger in mind, but most comanies slap on one an engine not designed for one, and to ensure no "kaboomage" the lower the compression ratio. your Zuki is alreay over 10:1 which is already considered high compression. I would change out rings and drop compression.... (if i knew what i was doing, which i dont).

  8. spaner

    spaner Well-Known Member

    Where's the beef !



    Way back when I was fitting the charger into the very small space in between the manifold intake mount and the carb, I had to adjust the clearance for the drive belt, truck frame, and engine block. Very tight all around.

    This was all done by eye, a 2' strait edge and a lazer alignment tool.
    I was able to get two mounting plates ruffed out of some 1/8" 316. One for the intake-to-charger and one for the charger-to-carburetor.

    Problem being that the original mounting bolts (intake-carb) ran across the sealing surfaces of the charger in a back-to-back "mirror-like" configuration. How can you seal a pressure vessel when the sealing surface runs across the top of a bolt head and the mounting surface needs to be adjustable; to finalize angle and height of the unit?

    These are the kinds of problems that I love. Something that a "professional" would say is imposible. This is how it was done.

    The 1/8" mounting plates were bolted with enlarged holes and standard bolts, having standard 1/4" (thickness) heads. A 1/4" thick flat rubber seal (with bolt head holes cut in it) was used to take up this differance like a sandwich and the charger was mounted on top of that.

    So you have a flat surface, mount a 1/8" plate, two bolt heads sticking out, a 1/4" flat rubber seal, with two holes in the rubber, for the bolt heads, charger onto that.:pop:

    Fine alignment adjustments were made and everything was "locked down".
    Run-up tests were done, but of cource, you can't have a final mounting with 1/8" plate supporting a 20lb supercharger and a carburator, all under "drive belt tention" and running at 7TRPM. So, things were "reverced".

    A "pattern" was made by spraypainting the outside of the seals and everything was dissasembled and "mapped" as to its' final positions.

    Finalized mounting plates were ordered using "mapped" locations and counter-sunk bolts into 1/4" 304. "cap-heads".

    This allows the use of 1/4" plate and 1/8" seal; inplace of the 1/8" plate and the 1/4" seal. A better mount and a better seal, in a finalized location for both the charger-to-intake as well as the charger-to-carburator while positioning everything into the same locations...1/8" + 1/4"...:sly:

    Clear as mud?

    Probably not, I think it's easier to perform a miracle, than it is to explain it.


    Attached Files:

    Last edited: Mar 13, 2011
  9. spaner

    spaner Well-Known Member

    Man, I am disapointed...

    At least o8K is giving his knowledge on the subject...

    An artist, sees a photograph in his head and is not satisfied untill the canvus he is working on represents his ideal image. A builder sees a blueprint in his head and is not satisfied until it comes to life. ;)

    Attached Files:

    Last edited: Apr 4, 2011
  10. fupabox

    fupabox Well-Known Member

    Just a word on intercooling (if you plan to .. it appears you don't) you can't on a suck through system as the cooled mixture will condense in the intercooler and Kablooie...I'm liking the thread but unfortunately have little hard knowledge in the mods you are interested in...If you need wrenching help tho..I would be more than happy to assist...i can even throw snow on you if you catch fire!:p
  11. Little Dumper

    Little Dumper Member

    I wouldn't do a suck through either (intercooled or not), the plumbing is going to be much to long for the fuel to stay suspended. Unless you bolt the huffer right to the intake manifold I would just save yourself some grief and do a turbo setup.

    You can make WAY more low rpm torque with a turbo than a supercharger, true the positive displacement ones are much better than a cetrifical, turbos just do it better. They also will make your mileage go up instead of down. A properly designed turbo system can make an engine run at 100% VE at light cruise, something an NA motor can't and a supercharged motor can only dream of.

    If you are craving instant throttle response, go super, if you can wait a whole second for the turbo to spool up you will end up with a much more efficient package that will bury a supercharge's torque graph.

    Last edited: Jan 24, 2010
  12. spaner

    spaner Well-Known Member

    Thanks Guys!

    Make no mistake though, this mod will be done, wrenches will be turned..

    RIGHTY TIGHTY, LEFTY...I'll have to look that up again:cool:
    Last edited: Apr 4, 2011
  13. fupabox

    fupabox Well-Known Member

  14. spaner

    spaner Well-Known Member

    Nice find!

    Buddy increasing his boost on an AMR 500 with a direct install 80% pulley & belt.
    I didn't even consider searching jp blogs, found my first Sambar engine bay pic in no time flat. Lots of project links too!

    Thanks Fupabox :D
  15. fupabox

    fupabox Well-Known Member

    Quite welcome Spaner......Anyone interested in the way to find a lot of the japanese stuff is to go to google..install google toolbar and enable auto translate ..then click more beside the video/images/web etc...click translate..translated search..japanese to english..then search away...make note of the japanese words used for the vehicle you are searching and write em down..minitrucks can be referred to as light tigers and for example there are about 10 ways to spell hijet depending on the model ... haizzettarukku for hijet truck,different for jumbo cab,van etc...search those words as well...tons of stuff but the translations are at times completely undeciperable,:(:(still fun tho:p
  16. Acerguy

    Acerguy Moderator Staff Member

    Plus I've found that Sambar often is Samber. Lots of things in Youtube also once you start digging in the Japanese threads. For instance, there are lots of exhausts posts on Youtube apparently featuring Sambars. :)
  17. spaner

    spaner Well-Known Member

    Theoretical Summarization

    POWER**** :)

    The popular prediction is that 7 psi of boost pressure adds 48% PWR: (14.7 + 7) ÷ 14.7 = 1.476.

    Actually, 7 psi is perhaps 80% efficient; the engine receives about 5.6 psi in terms of density.
    Compared to a large carburetor pulling .75 psi of vacuum at WOT, it’s worth about 21% more power.
    Compared to a small carburetor with 2 psi vacuum at full throttle perhaps 26% more power.

    For a better but still approximate estimate of boost vs. power, the first few pounds of boost is about 85-95% efficient,
    which tapers off to 50% by 15 psi. Multiply the boost pressure by the efficiency to get the relative density index.
    Now estimate the full throttle vacuum of the carbureted system in normally aspirated mode.

    HP+: horsepower increase
    ATM: atmospheric pressure
    D: relative density index (boost pressure × efficiency)
    V: full throttle vacuum, normally aspirated (typically between .75 psi and 3 psi), then:

    HP+ = ((ATM + D) ÷ (ATM - V))^.5

    HP+ = ((14.7+(7x0.8))÷(14.7- 1.5))^.5

    HP+ = 1.24 or 24% increase

    HP = INC X NA HP

    HP = 1.24 x 47HP

    HP = 58.29

    Low pwr TORQUE is what we are after...HP at low RPMs and successive gear ratios...

    Why not a turbocharger?

    Very few turbos are small enough to work on 660cc engines (exceptions include IHI for Subaru, Geo Sprint, T15, etc.)

    A turbo is not “free power” from the exhaust - the exhaust load is higher than NA (normally aspirated) under all
    conditions, which means more heat and pumping loss....
    [superchargers do consume more power, but also have a slight cooling effect under boost]
    [most superchargers have an internal lubrication system, or sealed bearings].
    [the stock exhaust works fairly well on a supercharged application]

    The TURBO installation is much more difficult:

    Without a bypass system and a small (restrictive) turbine housing there is no boost at low RPM.

    The entire exhaust system must be gas-tight (exhaust pressure = boost pressure × 2) from the port down.

    The exhaust system must be re-routed away from the engine, fuel, rider etc.

    With few exceptions they need pressure oil, and oil return which means either a separate pump
    and sump, or a position higher than the existing oil tank.

    Sizing of the entire turbo, compressor trim, turbine housing size and A/R ratio are far more critical
    than any supercharger. A mistake (no boost, low boost, overheating, too much boost) cannot be
    cured by adjustment but by replacing expensive parts - perhaps several times......

    Most supercharger adjustments only require a single pulley change.

    MIXTURE**** :(


    I know you are the most knowledgeble member on this site when it comes to the Carry CARBs...

    How can we best INCREASE the mixture, ON-DEMAND, from these little gizzmos?

    1, ACCESSORY DRIVE, my understanding is that this is a throttle INCREASE and has no affect on MIXTURE...

    2, ACCELORATOR PUMP, will increase mixture at WOT, but maybe difficult to control affectivly, on demand...

    3, CHOKE/TEMP system, will increase mixture..indirectly with restrictive meetering, but may be controlabe...through
    a ratio type system of BOOST vs VACUUME.....?

    Please give us your thoughts....

    Fupabox's INTELAJET find may be the work-around solution here...:rolleyes:

    DETONATION**** :)


    Lowering compretion ratio with a secondary head gasget and....

    Retartation of the timing by 10-25 degrees and....

    Replacement to lower temp plugs (AUTO-LIGHT) and an increase in gap- 40 degree gap and....

    Increase in fuel octain - up to 100LL (aviation fuel)....

    A complete BOLT-ON system is possible and will be effective with consideration of the minutia involved.
  18. Little Dumper

    Little Dumper Member

    What ever you do, do NOT stack head gaskets to lower compression, bad idea. The first time you rattle the motor (and you will) the gaskets will distort and at best start to give you detination issues that will drive you nuts because you will do everything to cure it and it won't go away or at worst squirm out and give you a huge coolant and/or compression leak. You should also tighten your spark plug gap. Forget AV gas, it's crap, I played with it for a while and it's not ment to run right below 5000 to 10000 feet altitude. Tolulene and ethanol works REALLY well, I can run 24 psi of boost in my GTR with 32 deg. of timing with only a 20% mix of Tolulene and Mohawk 94, makes 650hp at the crank.

    You should re-research turbos, most of your assumptions/findings are old and antiquated. Turbos are BETTER than free power, they feed into themselves, produce much less heat in compressing the air as a pos. displacement supercharger and don't add stress and vibration to the snout of the crank. A few people have snapped crank snouts off motors that have a dia 3 times bigger than what these motors have with supers only twice as big as what you want to use.

    I don't want to come across as a poo-pooer and think the project is really quite neat, I just want you to see it from all angles with the right info.

    Last edited: Jan 27, 2010
  19. o8k

    o8k Member

    Anyone heard of a VGT on a carburated engine? :D. Suppose a vacuum soilinoid might do...
  20. spaner

    spaner Well-Known Member


    Very nice guys...:pop:

    All is well Jon, just what I wanted, some of your technical experties...

    I am trying to get a blanket coverage of information on the subject and I've been posting some nuggets on the way...

    I want to eventually be able to post a complete system that the average jo can bolt on in the back yard to get a 50% gain in low RPM torque..

    Don't worry, I still have some ACEs up my sleave, if required...

    I've even considered a water-meth injection system...:cool:

    But I don't think that we are there yet.. :D


    Attached Files:

  21. o8k

    o8k Member

    Convert it to a 6-stroke! But if you do the water thing.... Just try to avoid Hydrolock um-k :D and if you cant avoid... Take pictures :D
  22. Thats the spirit,
    good old ingenuity. We have plenty of Subaru superchargers laying around, might have to get on the band wagon (once it warms up here in Japan). Carburater may be a bit tough as altitude for some people may be an issue. Going with an EFI solution may be easier as the computer can compensate ignition timing during boost with a proper MAF sensor or density monitor.

  23. MiniBrutes

    MiniBrutes Member

    EFI would be premo but can be a pain and expensive.

    I HAVE an F5A Supercharged being rebuilt right now. I will have to look closer at the setup when I get it back. I dont think there is anything special for enrichment.

    It is a pull-through OEM setup. No intercooling. This 550 should be good for about 55hp. 10 more or so than a 660 NA and yes, about 50% over a regular 550.

    If Don will sell some of his blowers for cheap, that would be a good route. Its already the proper size for the most part.

    Just set your fuel for WOT and only drive pedal to the metal ;)

    If I had to guess, I bet its set up a little rich at idle. It ran good before we tore it down, but the head was so pitted and corroded that I decided to get a different one. A little tough to find a good supercharged F5A head.....

    The engine is still in Asia. I picked it up when I was there in October. I think its actually done now. Just need to have it shipped.
  24. MiniBrutes

    MiniBrutes Member

    To lower the compression, Alto Works pistons are dished. Or, you could machine the top of the pistons a tad if there is enough material.
  25. spaner

    spaner Well-Known Member

    Thanks for chiming in there guys:pop:

    Yes compression can be lowered by various means, but I don't think that it would be necessary; considering the factory SC model of the F6A and the Practical BOOST level...

    The mixture enrichment, I had hoped that Minibrutes would confirm, but it can be controled with the choke system on the NA systems....

    For gasoline fuel, the stoichiometric air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be a rich mixture, any more than 14.7 to 1 is a lean mixture - given perfect (ideal) "test" fuel (gasoline consisting of solely n-heptane and iso-octane).

    An "ON-DEMAND" system may be controlled by vacuume activation through relays to control BOTH a clutch belt drive and an enrichment/choke combination. Giving FULL Practical BOOST at all RPMs...and the applicable torque increase in all gear ratios.

    BASE LINE mixture, can be set via the stock mixture setting, RICH; around 10-11; at idle, and low vacuume operations, and the BOOST mixture would run slightly LEAN; around 16; for PWR and torque requirments, considering a choke control system.

    Don shout-out...

    You have to email me back buddy..

    The availability of the replacement stock A/C clutch pulley is the deciding factor, for the use of the AMR300; or better yet, the AMR 500...

    It can be machined for mating on the unit, but the vacuume controled system cannot work with a direct drive system.....

    Do you want these guys to go with a bolt on system, or a turbo suzuki sprint replacement?...:eek:

  26. Sorry, been working on some Mitsubishi Jeep projects lately and haven’t had time to look for the 4” AC pulley ( Must be a few hundred laying around the shop…LOL).

    Yes, the electric clutch from an AC compressor is the way to go. I will still go with the EFI and not carbureted engines. The Subaru supercharger output duct is easy to modify.

    Simplest solution:
    1. Subaru supercharger
    2. AC Pulley
    3. Any EFI Engine

    You will also need to increase your tailpipe size. I learned this trick from James (Mega gearhead) Just increasing the tailpipe size a 1/2” puts out another 12lbs of torque at 4500rpm. Since we have a ton of superchargers and turbo’s here I guess I have no excuse but to start building one of these too….

  27. Little Dumper

    Little Dumper Member

    If I read your post right on the fuel mixtures, you've got it backwards. You want to be between 11 and 12 AFR under boost and 16 while under light cruise. Idle usually likes just north of 14.7. With a super charger you also want to make sure you don't go richer than 11to1 as it will shorten the life of the unit faster than it would with a turbo. Fuel contamination in the super's lube system is easier to do.

    You know, you could always go with propane, there are mixers that have more than enough capacity, you won't contaminate anything if you go too rich and it has an octane rating in the neibourhood of 105 pon (110 ron in Jap-speak). The missinformed stories of reduced power and milage are just not true (there is a slight loss of milage, but power....not a chance). When propane was huge in Canada back in the '90s, I took cars and trucks that had systems on them and gave back the power and milage that was lost while I was working at a local speed shop. Companies would put the systems on but not really tune for the fuel, or at least not nearly as agressively as they should have. With the octane rating you can really push the envelope and have no ill side affects.

    I may just skip the FI and just do propane or turbo/propane once I get my mini (it's on it's way.....yay!). A small system like that for a carbed engine should only be about $1500, ditch the spare with the gas tank and you could stuff a set of manifold LPG tanks in there 40% larger than the orig. gas tank to give you more range. Another side benefit is engine longevity, you can get diesel like km's out of a propane engine. A crew transport van that I ride in to travel from Vancouver to Boston Bar was just taken off the road because the chassis was too far gone, it had 976000 km on it, the engine had never even had the valve covers off of it and used no oil, ran like a champ. Propane is about 45 cents a litre here.

    Last edited: Jan 29, 2010
  28. If you want to go propane most mini trucks & vans could be ordered with it. Easy to do on the old Mitsubishi's and Subaru's. Fun to play with....

  29. Don-in-Japan

    Don-in-Japan Member

    For what it is worth, I was here in Japan in the early 90's when the grass roots forced induction craze was going on. We turbo'ed several vehicles, and the process was nearly always the same.

    For starters, the compression must be reduced considerably.. we were lucky, as the race shops here offered larger metal style head gaskets up to 2mm thick (which was the standard we used, since most stock units measured in at 1mm or slightly under).

    On carberated cars, we had a carb guru who could modify the jets properly on the stock unit, or Mikuni sidedrafts (which we used in a 400hp 240Z turbo car). Another option was draw thru, with carb mounted on compressor inlet (negating any intercooler). Yet another was "boxing" a carb, which allowed for the proper function, but gave more design headaches.

    EFI vehicles got treated to a larger fuel pump, and an Additional Injector Controller (AIC) like this model..


    The older models had a stand alone boost sensor which plugged into the intake plenum, which sent the signal to the controller. More boost=more fuel.

    The only thing on the factory setup after that we modified was the MAP sensor had to have a one way valve attached to it to avoid it seeing any boost (it took offense to boost). Any boost going to it was bled off, and it would see only vacuum.

    Nowadays, everyone here seems to run aftermarket controller systems like SDS and Haltech.
    Last edited: Jan 30, 2010
  30. spaner

    spaner Well-Known Member

    You guys are no fun...:(

    I'm going to start a new game while I wait for my AMR 500..

    It's called NAME THAT PART

    1) has to be related to the thread
    2) you have to know what it is and how it is (or could be) used
    3) you have to know where it came from or how to get one

    I get to start

    Attached Files:

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