DIY Ram Air

[artistic]

Would adding a funnel and hose to the air intake on my go kart engine have the same effect as ram air? Would I have to do anything special to my carb after doing this? Would I see a big increase in power? Thanks - andrew

[Reed]

im guessing your go cart doesnt go much faster than 40mph and at that low of a speed you would probably not feel an improvement.

i think you should try though cause the whole thing wont cost you more than a few dollars

[Jet-Lee]

I professionally raced go-karts for a few years...what kinda kart and engine? what size? 4/2 stroke? where'd you get it? is it made for racing or recreation? ALL this makes a BIG difference.....

[CBFryman]

im thinking of going down to walmart and buying a chepo breather and crappy $9 air filter to see if there is any difference at all...i think moving the air intake away from the engine and using a larger diameter tube will give more of an improvement than ram air...but if you do try it (hell its cheap why not) get a K&N filter that replaces an OEM square filter...then build a box to hold it and have it facing forward....more flat surface area=more pressue so that may actually work....ways of giving your go-kart performance are...Removing the govenor, adjusting idle speed to a high RPM, adjusting top end speed to a high RPM, taking your head off and smoothing out the "sharp edges around the intake/exaust side of the cylender (prevents hot spots) giving it beter spark advance (if using a magneto this is wasy...just adjust the flywheel a few degrees) and running a high compression and using ethynl instead of gasoline... but just remember your 5 or 8HP briggs and stratton isnt made to spin at 6,000 RPM or run a 9:1 compression....so it will be very highmantainence... but i have see nwhere the little 150cc 5hp 4stroke briggs make 15-20HP and 18-25ft/lbs of torque....also using a Jr. Drag carbrator (larger bore) and intake manifold (also larger bore) will give very large performance increases (as much as 2 HP...but when you are talking about an 8HP engine that is a 25% increase)....

[artistic]

Its a briggs and Stratton and its 3hp, 8cubic inches its a 4 stroke , not sure if its for racing or recreation , but i'd say recreation. I havnt built the frame yet. Another question , is 3 hp enough power for a guy that weighs 190 to get around in? I'm thinking most likely not and a 5 or 6 hp would be a lot better engine to get, correct?

[CBFryman]

if you buy new...get the 12hp or the horizontal V-Twin OHC...hella lot more HP...3HP will move more htna you think...just not at any high rate of speed...you may be able to get 8hp out of it if you want to do the MODS...kart engines are very basic engines so if you know the basis of a 4 stroke you can get yourself around...

[artistic]

I dont have the kind of money to buy a 12hp. My friend has a 6hp and it goes REALLY fast with him driving and me riding on the back.

[CBFryman]

Really fast as in acceleration or top end... i can switch out some gears on mine and make it go 50 where as right now it iwll only go 40 but i will be chokeing my acceleration...or i can swich some out and only alow it to go 30 and accelrate there very quickly...i have found just about the right balence on my kart...just enough to where i can get a lil squeak on cement or some rooster tailon dirt when i want to...but no so much that (since i dont have a diferential...just a soling bar as an axle) when i go to turn and i get on the gas too soon i spin out because i have too much torque to the wheels...i have a torque-A-Verter...its a variable diameter pulley that changes pulle ratios based on load and speed...so this allows me to go up steep hills and throught the mudd and water but also get failry decent speed on pavement even with me only having and over all diameter tire size of 8.5"...they are kinda expensive but well worth it since you have a pretty small engine...i think mine was 150 for an 8HP... its basicly a cyntrifical pulley clutch and a variable diameter pulley that in turn goes through a shaft to a sprket which then transfers energy yo another sprket via chain thich then gives the wheels their torque... i have dual band brakes on mine...they will lock up even with me and a fat firned on the kart on dry pavement....and i have no suspension on my kart so dirfting is easy and fun...untill i hit a pot hole are roll over only having lap belts....

[artistic]

Around here at like princess auto and such, a 6hp honda engine is 399 candian. Or it might have been 5, but around there. there are some that are like 15hp that are about 1200 bucks.

[CBFryman]

your could also go down to a junk yard and find a small engien with a horizontal shaft that isnt seized....dont buy honda...stick with briggs or techumpsen (i know i spelt that way wrong)

[artistic]

Whats wrong with the honda engines? MY friend baught a 6hp honda engine and it works great.

[flsurf420]

hook up a blow dryer to it, forced induction for ya lol

[Jet-Lee]

ok, here's some mod's for ya, from a pro kart racer...

Get a bigger bore carb, it'll cost a little bit. Smooth out ALL rough edges on the inside of the head, EXCEPT the outer rim, where it meets the gasket. Get a superlight piston. a shallower head maybe. K&N makes an airfilter for it, at least the 5hp. Run methanol, used to be $5/gallon, not sure bout now. Advance the timing, do this by pulling off the flywheel, take out the piece of 1/4" stock (the little bar) you can buy a new one or make your own, but it should look like a square S, so that the flywheel is adjusted forward half the width of the stock (or 1/8" at the crank, not sure how many degrees that is). Get an Autolite Platinum plug. Take your pullstart OFF. Only hold it against the engine when starting it, then pull it off (reduces drag against the crank).

Our karts were setup similar to this, although we had 5hp engines and used 3hp flywheels (stronger spark). We had direct drive via Centrifugal Clutch (the clutch was on the crank with a 12 tooth gear chain driven to our choice size gear on axel). Live axel (solid). With a 68 tooth gear in the rear, we could hit ~55mph on the track (1/8 mile). With a 53 tooth gear on the back, we reached ~110 on the Freeway (paced by friend in car). We also rebuilt our engines weekly and ran synthetic oil with a crankcase breather. We managed 14.7hp out of a 5hp block. A LOT of performance is in your fuel/air mixture.

Take it from a pro and have fun!

*EDIT* - With a 68 tooth on the back, we could stomp on it and spin the rear tires for a while on asphalt. We also had our racing clutches set for a quick grab at low RPM instead of gradual at a higher RPM.

[CBFryman]

or you could save your pennies and buy an old YZ125 motor...and Jet-Lee you forgot to tell him if running methanol or ethnyl to replace all steel fule fittings in the fileline and carburator with brass fittings as steel will gat all F'd up from the alcohol...

[CBFryman]

sorry for the SPing im tired as hell...hurricane started flooding the yard agian so i was up till 1 last night pumpin it out and then i had to wake up at 7 this morning to cut up a tree that was blocking the road... :-\