RE: Honda GX35
 

I've looked at forced induction on them too- a custom built positive displacement type blower would be the way to go. Any centrifugal compressor you come up with that can move enough air at enough pressure to do the job is gonna have to spin those high rpm's- you ever try to make a small, compact, lightweight, ratio increasing drivetrain that would be able to drive the compressor? It would be a cumbersome, high inertia 'abortion' of a gear train or belt setup. The one way bearing mentioned would be mandatory. It would take a serious engineering effort to do it sucessfully. This is one of those times when the scaling of the parts and pieces and capabilities is really working against you in a power transmission and also fluid dynamics sense. It may could be done effectively with a planetary type drive- but those = $$$$$$$. I'm not saying you couldn't do it, but by the time you got it worked out you will have spent the time and money to have just about put any engine out there on the plane or whatever. These Honda engines are just kinda lame.

If you want power from it, work on getting a billet cylinder head attached with better breathing capabilities- increase the lift on the cam, and also jack the compression up through the roof. Honda screwed us with the one piece cylinder/crankcase assembly.
H.

RE: Honda GX35
 

Hey guys do you remember that O.S. made a supercharged 120. If some one could find one of those.......

RE: Honda GX35
 

if you look in my thread, youll see im making a centrifigul blower based on the gx 35. i figure when im done it will be suitible between around 20 cc to 50.the first peice is a prototype i made from a computer fan- .75 psi ( unshrouded plastic fan) the following pics are of the wax 'core', hardened gears and blow-off

RE: Honda GX35
 

HI SUBARUBRAT! DID YOU USE THE STOCK CARB ON THE GX35? HOW DID IT PERFORM? THE OEM CARB HAS NO ADJUSTMENTS, SO WHAT WALBRO CARB (PART#) WOULD WORK? HOW BIG IS THE DRI,AND HOW DID IT FLY AND SOUND WITH THE GX35? THANX, BOB K

RE: Honda GX35
 

Hey subarubrat,

I would like to know what Walbro carb (part#)you used and where did you find it.I've got my GX35 running on a stand and I can't get more than 5500 rpm's.It will go up to 6000 rpm and it starts cutting out like it's starving for fuel.I'm running a MAS 20x10 classic prop I tried a Zinger 22x10 but the engine did'nt like it barely turned 4500 rpm's.I'm running a 1/2 by 4"long header pipe on also.

Thanks Jim Club Saito#509

RE: Honda GX35
 

Anyone[:o]???????

RE: Honda GX35
 

Hi
I am new hear, I want to find out more about the Honda GX35 engine.
1) Is this a reliable engine?
2) It has a timing belt, does it need to be change, how hard it is to change it? Where can I get a manuel of servicing this engine?
3) What kind of cylinder lining does this engine have? Just plain aluminum, chrom-plated or have a cast lining?
4) Any chance of piston hitting the valves on the stock engine if timing belt is broken?
Thanks

RE: Honda GX35
 

Honda GX35 blower

I modified the engine cover, making it into a scoop that catches the air from the fan and diverts into a tube which I ran to an enclosed box aroundan airfilter. Had trouble getting the carb tuned right, but definitely had a good midrange power increase. A good engine tuner might know how to take this and make it work, pretty simple. Maybe not? I dunno... I think the pressure interferes with the backpressure needed for the pump in the carb. Adowndraftcarb might work better...

RE: Honda GX35
 

An increase in atmospheric pressure actually helps because the diaphragm responds to pressure differential. The psi increase from the flywheel fins is so small it really won't make an impact on pumping, but the volume flowing into airbox does help.

Before the exspurts start screaming...
This arrangement was by ONAN on the ONAN performer twin cylinder engines, it does work.

RE: Honda GX35
 

I know you guys are a already going down a path with a blown honda, but I had an abstract though with regard to blowing one. Why dont you create or "find" a positive displacement blower based on a vane type compressor. These type of compressors dont need godawful speeds to be efficient, you could run it around the crank at crank speeds, draw through the carb for simplicity and have a linear output based directly on rpm's. You could probably run a little oil in the fuel too to help with lubrication.

RE: Honda GX35
 

:D My engine builder is doing exactly that, a vane compressor designed from the ground up specificly for the honda.The vane type has several advantages, internal compression has less heat created from compressing,it doesn't have to run outrageous speeds, its simple to make, yup and draw through with oil in the gas.
I think the tip speed on the vanes at extreme rpm is well below the Judsons used on VWs so there is no problem with speed.
Weight might be a problem for aircraft from what I understand the compressor replaces the intake manifold so size should be ok.

Plus it eliminates the spitback problem,no raw fuel going into atmosphere. Bob says because of that it should be regarded as an emission device.[sm=thumbup.gif]

The only real problem is the fuel pump,with no pulse returning from the engine the pump won't work.

RE: Honda GX35
 

If you could get the fuel pump pulse to take its signal from the inlet between the compressor and the engine, you should get the pressure differential in pulses as the inlet valve opens and closes to work the fuel pump. My initial thought was to mount such a compressor over the crank bearing " projection" . Most engines of this style project a little once the flywheel is gone. I thought you could make the compressor in a "doughnut" style and mount it over the crank snub and run it directly from the crank , not using any drive system thus eliminating another headache ( but possibly creating another in the form of sealing the thing)
... I wonder how it would go on a 2 stroke, an idea like this.

RE: Honda GX35
 

If you can make a supercharger, you have the skills to make a small diaphram air pump to run the carb.

RE: Honda GX35
 

Not my project (or problem) and I'm not updated on it, but I pointed it out as its a universal problem with any type of supercharger on these engines.

Personally I feel the Shindaiwa C-4 technology which is a piston supercharged engine solves the problem without any other weight or added parts.