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ChadS
04-22-2005 07:44:47
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Re: Vinson manifolds for IH in reply to clarence barenie, 04-22-2005 04:14:35
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Im hearing ya! Ok, let me see if I can get scientific here too. LOL! First off, you ever hear a H with a 8043DD head with 300 psi of compression crank over? I bet I go through 2 or 3 starters a year cause it cranks so hard! Ive busted the starter clean off the housing before! I broke down, and built a starter for the H, started from brand new, and now days,, when I hear the starter act sluggish, that tells me Ive burned up the brushes in the starter. Replace em, and it wil crank it like a stocker with a 1000cc battery. Now, on the 450,, had to replace the starter, cause the old one was junk, but thats a different story,,, Id say that what I did when I built the engine, I did in fact increase volumetric effeciency, more air thru the carb, (biggest venturi available) More through the intake manifold, (did nothing about that) More air thru the head ports on the intake side, (stock ports not polished) Thru the valves, (stock valve train) and more air into the chamber, (added high compression pistons, and a small stroker). With all that, I increased efficiency thru the intake side of the engine. granted, the stock 450 manifold will not flow enough air to feed this engine much above 10% over rpms. and its only 307 cubes, at 210-215 psi of compression! Stock was 281 and 125 psi! went from 58 hp up to 85+ 28 cubic inch increase now,,,, and picked up 90 psi of compression. Id go out on a limb, and say, the volumetric efficency for 307 cubes for the stats is border line radical. Vacuum levels, are very very high in the manifold, which in most cases in farmall engines, its the total opposite, low manifold pressure, but its got the biggest carb and intake to run it. Therefore decreasing efficeincy. cause the engine cant draw it through. Not enough static compression to properly take advantage of the new intake and carb is designed for. In the engines I build, its back to properly setting up the induction system to take advantage of the efficiency increase, which usually means big venturis, and big intakes, port and polish work. Id say no cam changes, simply because the air that is present, can be made to flow more smoothly by port and polish work, and bigger intakes, and carbs. All you have to do is make room for the extra air/fuel charge. Now, it stops at the intake valve when its in stock form, but,, in order to know if the valves have to be enlarged, or unshouded, or what have ya,, is if, when on the dyno, you have a characteristic, that cant be changed by making other adjustment to compensate. say like you have it at 540, run it, shut it down, and even though it smokes out the pipe, the plugs are white as snow. you can jet it jet it and rejet it again, and still no change in the plug color. That tells me that a limit has been reached for the limited intake, and head ports and valves, increase in size will help the efficiency. you mite pick up some HP, but not much. 5-6 hp if that,,,, but, afterwards, you have an engine that can utilize all the potential created from a high compression, high effieciency engine. Limitations my friend, you can only go so far, with what is there, and when more is needed, 2 choices, A: do it yourself and git r done, or B: buy the expencive parts, which may not be legal to pull due to the part numbers,,, but its only $$$$$!!!!! !!!!! Not my $$ so I will take plan A. ChadS
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