:::RHMT::: Real Home Made Turbo
General Category => General Discussion => Topic started by: HiProfile on September 10, 2010, 10:38:48 PM
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I'm not building a gas-powered scooter, YET. However the Doodlebug thing I found looks badass for a cheap pocket dirtbike.
Instead I'm thinking my next project will be a DIY pressure washer (once I close on my house). The local rental place sold me a new 3500psi/4gpm replacement pump (Landa), along with an old gun & hose. I got it for near nothing since they only have small pressure washers now and don't give a shit. Basicly it just needs a motor, since it already has the unloader valve, inlet/outlet fittings, soap injector, and pulley.
The only problem is the pump normally used a GX270 (8.5hp) from what the guy said. I plan on using a HF 6.5hp clone. However...this is RHMT, I only expect to make 6.5hp at 66% throttle!
I'm thinking I'll mod it a bit:
mod or remove the governor
add some 1.3:1 ratio rockers (stock is 1.1:1 iirc)
18lbs valve springs
lap the valves
file the timing key to increase timing
mill the head down to bump CR
mig up a better flowing header, but long enough for a wideband...
bigger air filter + diy billet adapter
mild head port
regapped rings (from oversized rings) + plateau hone
rejet the carb
It should have more HP than a GX270 and still be rather reliable. It would make a ton more if I wind it out, but that won't benefit the pump. All this shit (inc. motor) shouldn't cost over $125, given a decent HF discount + parts + tax. Plus I can order most Honda small-engine parts at work for cost. That will make a crazy pressure washer for less overall than any POS vertical shaft units at homeboy depot.
My basis for modding the motor:
http://personalpages.tds.net/~nascarfans/TripleDouble.htm (http://personalpages.tds.net/~nascarfans/TripleDouble.htm)
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Well since nobody cares, here's an update. I looked it up and this pump only needs 7hp to run, which is perfect. Retail is somewhere around $550 for this pump. ;D
I'm gonna start ordering parts from work: OEM GX160 piston to bump compression to 9:1, OEM con-rod, OEM retainers, various gaskets, and extra jets to play with. There are 2 GX390 carbs here just collecting dust I'll be making an intake for. I'll have to use ebay for the rings, not quite sure for the pulleys.
At this point I'm contemplating an old smog/air pump for supercharging...
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Your pressure washer build is more complex then most turbo builds on this site
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remove the governor
18lbs valve springs
lap the valves
file the timing key to increase timing
mig up a better flowing header, but long enough for a wideband...
bigger air filter + diy billet adapter
rejet the carb
That alone should get you around 9-12hp from what Iv been told.
Local cart guy made 14hp with just a good break in and this list. his kid smokes every one else
I think he dropped a cheater cam in tho.
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Your pressure washer build is more complex then most turbo builds on this site
I dream big so when I half-ass it, it still turns out okay. I think I'm addicted to this because I can't afford a b-series engine build atm. At least I'll have my own house to work on it soon.
From what I've read, the 18lb springs bind around .300 lift, so I'll be making my own 1.2:1 rockers. Cut & weld. I'll also change the rockers' angle so the pushrods aren't "short". I also found someone who welded & reground their own cam, but that's going too far for me.
I also have a flattop piston on order, OEM Honda rockers, pushrods, HG, guide plate, retainers, extra jets, and con-rod. I also scored two GX390 carbs - a Jap-built aftermarket & a used OEM. Then I might get some oversized moly rings an online shop has for cheap, depending on the CDM ring gap.
IF this pump doesn't require new packing/seals (might have been used), I'll be ordering chain drive sprockets and some #50 chain for a killer price. They'll put the motor at ~4400rpm, at which box-stock HF motors put out ~7.1HP. Since 7HP is the min, I should be good. Worst-case, I can get the pump seals from work.
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True.
Iv never built a pressure washer before, but the stock clone scooter with 10/48 gearing picks up the front with fat ass.
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Take the cost of a Honda... subtract the cost of a HF clone. Take difference and buy a cam, aluminum flywheel, rod (you can with the amount of money you'll save), and you will more than double the output. Honda clones are so dominant due to initial price they have their own kart class.
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Take the cost of a Honda... subtract the cost of a HF clone. Take difference and buy a cam, aluminum flywheel, rod (you can with the amount of money you'll save), and you will more than double the output. Honda clones are so dominant due to initial price they have their own kart class.
I would build a box stock If there was more of a carting scene around here.