Twin turbo flathead

flssaturday

Junior Member
Doing a twin turbo setup an a 49 merc 8cm. Any advice or idea's on what internals ate needed to handle boost.
Piston bore,intake valve size,exhaust valve size,gppd came . Ect.thanks

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There is a lot of information out there on supercharging flatheads. I would think a lot of it would be similar.
 
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Twin turbos can equal twice the headaches. Makes for a very busy engine compartment and exhaust system. I had enough troubles with only one on the old 47G3 series helicopters. When it is all working right it will make the engine breath but it takes a while to get over the turbo lag. The little ones spool up faster but they don't pump as much either. It will still have some lag. Would be Ok on the long dry lakes though. For street, it's hard to beat the roots type supercharger. Be prepared to spend a LOT.
 
You might want to contact Jack Stirnemann in St. Louis. He built a twin turbo flathead a few years ago. He and his brother Harry can do amazing stuff with flatheads.
 
Depending on what power you aim for steel main caps and if they are oilcooled perhaps a higher flow oilpump and an oilcooler.
 
Hit the search link at the top of the page and type in twin turbos. I posted my homemade setup setup back in April. You don,t need larger valves, stock compression is low enough, and we usually run premium gas. It will run o.k. on regular if you don,t run it hard. I limit the boost to 5lbs. You will like the way turbos make that Merc engine run! Good Luck!
 
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