Good evening I'm sorry if this has been a topic before I looked quite a bit and couldn't find much info. I'm a new member here so a little background info on my project. I'm a welder by trade and I built my rigid frame from scratch myself, I have a Merch performance 100ci fatso engine that I am using and building a turbo setup for it. I have the basic idea of how the blow through setup works but I am having a hard time figuring out how everyone did the intake plenum/carb inlet. I see many block off the atmosphere vents and pressurize the bowl breather and in that case I would imagine they don't have the carb in a sealed plenum and are just running a silicone connector to the mouth of the carb? Since aerocharger isn't making carb turbo kits anymore I can't find one of their sealed plenums for a mikuni is there a company that makes them so I can go that route? I have the capability to make my own but I'm not exactly sure how the carb mounts to it and how it mounts to the intake manifold etc. I hope this question makes sense I'm sure it's a lot simpler then I'm making it out to be and once again sorry if this has been answered before. Thank you

 

Hey...you will find bugger all info on the Internet or anywhere about specifics dealing with blow-through carbby setups. I run a CV Kehin with an Aerocharger and had to do a truckload of research and reading so as to understand how things all hang together.

The Mik is a good carb and I plan to upgrade to one at some point in time although the CV is a far easier unit to work with (thats just me being familiar with the setup). Getting the float bowl and overflows at boost pressure is the tricky bit. Some model CV's from the harleys actually have the overflow and the vents all running internally to the mouth of the carb so yu pretty much do not have to do too much other than put in bigger jets.

The Mik should work well although double check the accel pump area where the actuator rod enters the unit as I think that this will be a problem area and vent ful if the unit is pressurised. I have seen a mod to the carb where the bit is sealed and pressurised so as to avoid the problem.

Any backing plate will do - no matter what you use it will have to be modded so it could be easier to make your own out of steel. I plan to use a old S&S cover as I like the teardrop shape.

Use a late model Harley one piece manifold, but it will need tweaking to fit the Mik (a CV is a n easy fit)

Check out my website @ www.turboharley.com.au

 

ThaNks for the reply! I checked out your website and there is a lot of helpful info! Do you think you could send me a pic of your plenum that goes on the cRb from the charge pipe? I can't get aerocharger to let me even see what it looks like or how it fastens to the mouth of the carb. I'm sure I'm over analyzing it but at this point I plan to make my own and just want to see what the back side looks like and how it "clamps" or fastens to the mouth of the carb..

 

RcCustoms where are you located?

I am still running 3 Aerochargers, 2 on 94 and 95 Ultras and one on my 05SE vrod.

The guy that started the company that did the original Aerocharger development and kits lives near me in Batavia NY? I bought 6 of these kits back in 96 and installed them on Ultras. Heritages and wide glide. the original kits came with the HSR42 with a top entry plenum running around 12psi and getting around 95/100. After some additional development they found that buy going to a center inlet plenum and running the stock CV carb they could get almost the same 90/95 at 8 psi which helped stay away from detonation? I may still have an old plenum around and 1 or 2 HSR42 carbs from when I did the upgrade to the 2 Aerochargers I still have on mine and my brothers Ultras? I will look around this weekend and see what I can find? I may be able to contact the original owner and see if he has anything left laying around.

PM me I have the original manual in PDF from a scanned copy if you want it? the pics are kind of dark but I think you can make them out?

Dennis

 

That would be awesome if you still had a plenum laying around, I'm in ct so you're fairly local. I'm new here and embarrassingly enough can't figure out how to send a PM so if you want to send me one I would be more then happy to take a look at those pics you have and if you still have the plenum that would be awesome! Thank you!

 

just sent you a PM! Let me know if you got it?

Dennis

 

I sent you an email! Thanks Again!

 

Any chance I can talk you in to emailing that pdf to me? Does it go through carb modifications? Already have a 2.3 float valve and big jet/needle kit on the way, but I'd like to see how "the professionals" do their carbs

 

Chris

Unfortunately the Manual is just the owners manual I got when I bought the kits back in 96! It only has details on how to install the units! There are no details on how they modified the HSR42 it was already modified in the kit. When they developed the Center inlet plenum they went back to using the stock CV carb! I just gave them my modified CV I removed when it was NA before I installed the Aerocharger and they gave me a new stock CV carb and center inlet plenum as a free upgrade in 97 or 98 cant remember? I made 2 trips to Sturgis with the HSR42 so it must have been 98?

Sorry I don't have anything on the HSR42 carb mods? I never had any issues with it so never delved into it to see what they did to it it just worked and when we put the CV back on and changed the inlet plenum it worked and we are still running it that way today?

 

There's still shops pushing boost through carbies in the car world man ,maybe that'd give you a little insight ?
GraemeR would also have something for you too,even just down to little things you might miss.