Stroker kit [as rg97 suggested], high rpm cam, big carb and big head flow.Originally Posted by Honda_ATC
Do you know what mods your friend did?
Power “feel” is a subjective opinion. Actual power is best determined by a dyno. In general, you cannot increase power everywhere in an engine. You can have more power on the bottom, mid or top, therefore you need to determine which ONE is the most important to you.
In general, the bigger the cam, the more it raises the entire operating range of an engine. A big cam starts producing “power” later and quits later.
Increasing the displacement will net you the biggest overall increase in power imo. There is no replacement for displacement or nitrous, lol.
What type of racing exactly ie., drag, long oval, short oval?
Do you use a wide or narrow powerband for this?
Just curious, why did you guys choose the mega cam over the web cam?
Megacycle states that their durations are taken at .040” lift. The web cam "duration"is taken at .050”, the ADVERTISED duration is likely taken at .006" or .015".
Since Megacycle only states one duration, and does not specify whether it is advertised duration or not, it seems difficult to compare all the differences between the two cams.
Since the lift is the same on both cams the other differences are lsa, overlap and possibly icl.
The mega cam has an lsa of 106 and the web is 109. Since you are looking for max top speed AND a wide power band, from what I can tell so far, the web cam with the 109 lobe center will work better for this purpose imo, however, if shortline10 has tested both these cams in the same set up back to back, I would go with his recommendation.
78-85 200X CAMS
Mega cycle p/n 143-40 143-40NS
Lift .435 dur @ .040" 272 lsa 106
In 30 btc/62 abc
Ex 62 bbc/30 atc .006"
Must cut cylinder head for lobe clearance. Use R/D 228-H
Web cams p/n 55-72
Lift 435/.395 adv dur 288/288 dur @ .050” 262/262 lsa 109
Intake Opens 22° Before TDC
Intake Closes 60° After BDC
Exhaust Opens 61° Before BDC
Exhaust Closes 21° After TDC
Check all clearances.
PARTS MATCHING - One important thing is to make it work together as a package, the gearing, compression, cam, ignition timing, head flow and carb etc. should All be matched to optimize performance of all the various parts.
COMPRESSION – This must be matched to the cam, the type of fuel you use and ignition timing. You need to calculate the DYNAMIC compression and cylinder cranking pressure to determine what is beat. The STATIC compression will NOT tell you this, it is only a rough indicator. You must account for elevation when calculating this also because you lose around 4 3/4 - 5 psi of cylinder pressure for every 1000 foot increase in elevation above sea level.
EXHAUST - In general, an exhaust with a straight through muffler provide the most top end. Supertrap makes both types of muffler/silencer. Some tracks have noise level restrictions. A straight through Supertrap might net pass.
ADJUSTABLE CAM GEAR - Once your build is running, if you decide you want a bit more top and less bottom or vise versa, you can change the cam timing with an adjustable timing gear. Web or mega may sell them. 8 degrees is the recommended max, 4 is a preferred max. Check valve to piston clearances after wards before running.
More adv = more rpm less bottom end.
Less adv = less rpm, more bottom end.
As rg97 suggested, shortline10 and four stroke tech are good sources of info.
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