so i have this crazy idea to run my McCulloch supercharger on my olds rocket , witch has a 4-2 manifold on it with 4 97's , but im not sure if its possible to make 97's "blow through" carbs because of an issue with to much fule presure an the needle or something like that?? im not totally sure but id really like to know! ive looked in all my vintage mags and one the web and cant seem to find anything othere then a guy in a new hotrod mag is but it dosnt say anything about it. there must be a reson! has any done this or heard of anyone doing this!?!? please help! thanks
Your Mcculloch forces the air down through the carb, is that correct..How are you going to make a plate of cover the 97s and not lose air???? Try it and see what happens. The fuel pressure comes from the fuel pump. I'm not sure what degree the syphoning would be from the fuel bowl through the emulsion tubes and the use of the power valve???? I like the idea, keep us posted on results.. Duane..
When normally aspirated 97s require very low fuel pressure ( from the pump ) .......in the order of about 3 lbs..... Any more and the float will not be able to close the needle and seat...... If you use a blow through system on them the bowl will be presurised through the vent, once blower pressure reaches the smae pressure as the fuel pump there will be no fuel coming in. You could try using an adjustable pressure regulator which references from the blower so that the pump pressure rises as the blower pressure rises.... always staying about 3 lbs higher than the intake pressure. The tuner guys have regs like this on turbo cars but they work at much higher pressures than you need.... you will need to research and find one that works in the 0-7psi fuel pressure and 0-20 lbs boost . Also you may need to look at sealing the throttle shafts ...requires machining...... and with Strombergs you might have issues with gaskets sealing, they have enough trouble N/A. I don't think the power valve/pump bypass on a 97 will be affected .... there will be equal pressure on each side of it ........ You will probably need to increase the main jet size for the blower though and mess around with the point at which the power valvbes come into play.....might be OK with four of them at a time with no mods. Just do it , and observe the results ...keep us informed, hotrodders just do it and lead by innovation.
You'll have to pressurise the float bowl from the throat of the carb. The fuel pressure will have to increase with the increase in blow from the McCulloch. The carb will have to sealed completely like throttle shafts machined for O-rings. The float will have to solid otherwise it will collapse. This is just the stuff I can think of right now, I'm sure there's more. Its possible but very difficult. The easy way to use 97's with a blow through system is to completely enclose the carbs in a airtight box and then have the McCulloch blowing pressurised air into the box rather than directly down the carb. Because the carb is pressurised both internally and externally it will function as normal with no modifications and you'll just need to jet accordingly. Downside is it will be ugly and you won't even see the 97's. If you can't can't see 'em, why run 'em?
Carburated procharger kits put the carburators in a sealed box that is pressurized by the supercharger, that eliminates all the other problems of messing with floats and stuff.
Id say just a bit <object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/4RNs-NDN2UM&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/4RNs-NDN2UM&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
you know this guy? or dose anyone on here know him? id like to talk to him and learn a little bit on how he did this because that setup and car is just bitchin.
Top secret, but it involves rubber donuts & O rings. PM "Hot Rod Packard" on here. He might enlighten you, but being the butthole he is, I doubt it.
So why not build a box around the carbs, and pump air around them? not the best looking solution but it should keep them from leaking and correct me if i'm wrong but if you put the fuel pressure regulator in the box it would also keep it at a couple LB's above boost. OR if the box is too much what about just putting the fuel pressure reg inside the tube going from the blower to the carbs??
ok uncle max i sent him a messege , hopfully he's willing to help!! that would truely be awsome. i dont know if you know him or not but if ya do could ya maybe talk to him for me an see if he'll help???
After being on the cover of HRM, he's never been the same... I'll see if I can get him to come down off his throne for a minute. It must be very lonely at the top, but maybe he'll have time for us non-wizards. In the meantime, keep PMing him & I'll do the same. I'll have my people reach his people and hopefully get an audience with his highness for tomorrow. Otherwise, I'll just drop in on him.
Putting this topic back to the top hoping to find some more info since the original post is now 5 years old Im currently building myself a 296 ci flathead I have purchased a VS-57 McColloch supercharger assembly previously run on a flathead with a 4 barrel manifold i also have a new navarro 3x2 setup with 3 new 97's id like to make functional with the VS-57 any help would be appreciated.
I know this is a very old thread, but I am in need of the information as well. Trying to set up 48's with a vs57 Sent from my moto g(7) power using The H.A.M.B. mobile app
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