Stage 1 Upgrade Not Impressive

[mckutzy]

What is the machine and rear tire size...

 

[BigWes]

Like mentioned before as well, the jet makes a huge difference. The jet GPS sends is a generic jet that is only a few sizes larger. It is not optimal by any means. That's why there are actually jet kits you can buy. Normally speaking when you open up the airflow both jets really need to be replaced for the carb to work optimally. Most stage 1 kits only supply the main jet and not the one under the idle screw. In actuality the two working together will make a difference in how the engine comes off of idle. Just because it seems to be idling with that big open filter don't mean it's right.

Don't let this stuff get you frustrated bruh. I think the biggest part of the selling point for the stage 1 kits from folks like GPS is it gives folks that racing look and feel. And those guys send just enough carb jet so that most engines in that 196-212cc range will run after the parts swap or the biggest...

Here is an example of a jet kit like what I'm talking about.

https://www.ebay.com/itm/133068044512

And lots of times you can get these in various size ranges at no extra costs.

Ride your kart around and enjoy it. Don't get stressed. Fun is what this is all about. And when you get ready for more folks here will do the best they can to help even though it is only typing words and sharing thoughts.

Everybody will have different ideas and surely different results. I have decent results over stock but I also tweak the setup as well but I'm also an experienced mechanic with lots of tools and my own ideas and expectations as well as a good understanding of each setups limitations.

I always remove the stock plug of every small engine I own and replace with an autolite plug. Usually a performance type plug. It's just my preference. Does it make a difference? Maybe, maybe not.

I change oil and remove fuel bowls and clean carbs and pull the internal tank screens on a regular basis as well. Difference? Who knows.

I do have a stock non hemi 212 that will run 40mph. It has a stage 1. Governor still installed. Big Murray Explorer.

But, there again, I will say speed ain't everything if you ain't having fun. I had the same kart geared to run 45-46 with a different sprocket. But it had no bottom end at all. It just wasn't fun.

If we were neighbors I'd love to help you get it like you wanted it. But I'm a visual hands on guy. I'd want to listen to it run and see how it behaves when you drive it that way I could diagnose it right.

Hang in there and don't give up. You got this. Just take a minute.

 

[65ShelbyClone]

The problem has been identified: a governed engine with no gearing change and mods that don't really help in the governed RPM range.

I'd gamble a guess that the air filter is why you lost e.t.. it's like putting a 3" intake on a Honda Civic, you'll gain flow up top while sacrificing your lower end torque, it all has to do with velocity!

The air filter is not a tuning device; it will contribute to runner velocity by being as large as possible so as to reduce restriction as much as possible and let the port do its job. Reducing velocity through the filter medium also improves filtration. There is nothing to lose at all by having an oversized filter.

With an EFI engine that has a plenum intake like most Civics, all the tuning happens behind the throttle body. Everything upstream of that is a restriction. Reducing that restriction almost universally raises their entire power curve, even the low end.

The stock "intake" on GX series and clones actually have a intake runner that "straitens" the air (laminar airflow) and aids velocity whereas a filter right on the carb does not, it just allows it to breathe better in the in higher rpms where the stock "intake" becomes a restriction.

How does the convoluted plastic box function as an airflow straightener better than a cone filter that provides a straighter shot down the carb and runner?

 

[olddognewtricks]

Well, maybe the problem has been identified, maybe not. I am not convinced. Why? Because I now have more evidence wherein stage 1 kit performance improved ever so slightly with the governor in place.

But, first, the biggest issue I have with most retailers who sell these Stage 1 kits is this -- IF your statement is true that engines must be UN-governed in order to see any performance gains, then they should state that on the product pages instead of making blanket, generic statements about how you'll gain power just by installing a stage 1 kit. It makes the product sound like "snake oil".

Second, -- I put my Hemi Predator 212 on the frame. The Hemi is also stock and the governor is in place just as it came from the factory. I again ran 2 sets of repetitive tests -- the first tests were run with the Predator in 100% stock form, the second tests with the Stage 1 kit.

With the Stage 1 kit on the Hemi Predator, there was a .75 second improvement in point-to-point speed across several tests versus the stock Hemi. So, the stage 1 kit seemed to slightly improve acceleration EVEN WITH THE GOVERNOR IN PLACE!

Top speeds on the Hemi Predator with the Stage 1 kit were SLOWER than the stock Hemi Predator.

Obviously, this is not scientific. So, variations are to be expected. But, two things stick out.

1) For this Stage 1 kit on my Predator Hemi setup, having the governor in did not hinder some improvement in acceleration (though top speed suffered).

2) Oddly, on the GX200, the stage 1 kit was WORSE across the board. I can't figure that out, but I don't care.

The Hemi Predator 212 is plenty fast in stock form on a single seat go kart. I don't need to spend $80 to "maybe" gain 3/4 of a second in acceleration, which is far from guaranteed in the first place. Racers do, backyard yahoos like me do not.

Have fun. Go fast!

 

[Brianator]

An air filter is not a tuning device

Agreed! Lack of an intake runner is more what I was referring to, I should've gone into more detail but didn't want to write a novel

If we pictured air filters as trees (as they break up the wind and cause gusty turbulence) and a intake runner as a jetstream (straight uninterrupted flow) obviously the jet stream will have smoother, faster flow. A long smooth path (even with bends) before and or aft the carb will give the air a chance to smooth out and slipstream making it faster.

How does the convoluted plastic box function as an airflow straightener better than a cone filter that provides a straighter shot down the carb and runner?

I don't see it as convoluted at all, it's a simple elbow that's longer than even a filter adapter and therefore gives the air more of a chance to "straighten" out (align in a uniform manner).

Bottom line is he said he his kit had a noticable negative effect with the governor enabled and I had a suspicion that lack of a intake runner could be the cause due to its importance in lower rpms. Theres a fine line between restriction/high velocity and finding a good balance, too small you're great down low and starve up top, too big you kill low end but do good up high.

Sorry if I caused and confusion and if I'm wrong I'm wrong I'm not too big to admit it! It was just my "take" on it. Just for the record I have spent countless hours researching air and fluid dynamics for various things and have run many experiments to see the results first hand.

One that has baffled me is certain engines I've had in the past refuse to run well without a air filter in place despite tweaking the tune... things that make you go hmmmmmm...

 

[anickode]

Loooong standing engine tuning theory says that a long, intake runner increases bottom end torque, while a short, wider one opens up the top end.

Why do you think you see hot rods and race engines with the carbs sitting atop a foot tall intake manifold? It's not just for looks.

 

[BigWes]

Hey olddognewtricks, you will find that a lot of your generic parts are somewhat biased towards the predator engines. Consider 212 cc versus 196 cc. You have a displacement difference of what 16 cc thereabouts? It doesn't sound like much but the math leans towards being close to being what 8% difference in displacement between a GX200 and a predator 212? I am likely wrong. But that is considerable actually when one is randomly swapping out carb jets.

And you installed what came in the stage one kit just like all of us noobs did. And nothing is wrong with that. But if you want more you have to go get more.

The problem with these jacka$$e$ that sell these kits is they never sell anything for a specific engine. They also never give you a full kit to tune your engine for your gearing either. Nor do they give you the low side jet. Most folks that are running karts around the back yard really never notice it...but if you get down to the nitty gritty of ET's...that idle circuit jet makes a lot of difference. When you open up your exhaust and intake you need to richen your idle circuit as well. Why? To prevent that stammer when you slap the throttle down. Does it make a difference? I promise that you can measure it on your timer. And I won't even get into e-tubes. I am not a guru or pro on those nor do I claim to be but I do know that the inner diameter of your e-tube is supposed to be a certain diameter according to your jet...at least that is my understanding. Mine do not...but then I am not looking for extreme performance so I don't care. On my one built engine I have a mikuni carb. It seems to do well at this point.

Keep in the game brother.

 

[TheInspiredFool]

Did you take the plastic restrictor/insulator plate off when you installed the carb spacer? If not it could cause performance issues. If so, keep reading and later I will suggest you put it back on lol

My opinion, for what it's worth, is that when you added the high flow filter, intake, carb and header it increased the entire intake and exhaust system diameters, which dropped your total air flow velocity in and out of of the engine. Without adding increased rpm capability you probably won't see much in the way of gains below 3600 rpm. You increased the total amount of air flow capability in an engine that would see benifits with a higher velocity so that you can benifit from the faster charge of air ar low valve lifts where engines that only run below 3,600rpm get all of they're power from.

High Velocity intake and exhaust systems are vital to low rpm engines because the piston speed never gets fast enough to actuate the air up stream quick enough to properly fill the cylinder and then the exhaust is lazy and only evacuates the spent gas without providing any pre-charge pull to the intake during overlap. I would try a smaller diameter intake runner pipe and smaller diameter header pipe to try to get the velocity back up. Then tune your carb by fiddling with jetting.

A 3,600rpm limited engine lives or dies depending on low valve-lift efficiency and proper exhaust scavenging during overlap. If you have big high volume ports that are slow to get the charge moving and in right away then performance will suffer no matter what. Same with the exhaust, if you have a big port and big exhaust it doesn't exit the combustion chamber with enough speed where the tail end has the velocity to tug on one intake charge during overlap. If you properly reduce the intake runner and exhaust header diameter you can increase the velocities a great deal without loosing any power at all in your limited rpm range. It will make gains across the entire rpm range.

The Honda combustion chamber is not as efficient as the hemi predator is and I believe the crank and cam specs are a tab bit different as well which could lead to the reason why the predator gained some while the honda lost some. Plus the stock Predator intake and exhaust seems to be more restrictive than the honda which could lead to the gains and losses results upon switching as well.

As for the longer intake runner that should have an improvement as well. The longer tube would allow a slight "ram" effect in the lower rpm range that your engine runs in as well as provide some stress to the charge along the walls making it seem like it's a smaller diameter tube to the a/f mixture which should increase the velocity of the charge in the center of the intake runner. In addition you can increase the length of your exhaust for more positive effects.

No matter what it's always good to jet your carb and tune it properly. There is no one jet combination fits all type of thing when it comes to completely changing both the entire intake and exhaust system designed to go on a variety of different engines. Half of the battle is tunning it properly. And half of the satisfaction is knowing that you figured it out and got it running so great.

Here's a silly thought since you don't want to mess with much. Put the plastic insulator back on your intake real quick (if there is no air leaks with it on) and take it for a spin. If there is ANY improvement then you know that theslight bump in velocity made enough of a difference to overcome the restriction that it caused and your problem is too low of a velocity.
Well, that's my long winded 2 cents. Hope it helps.

 

[bob58o]

Can’t have your cake and eat it too, but who wants to have a cake sitting around.

If going to modify, remove the governor.
If keeping the governor, don’t modify.

Did we at least back out the throttle stop and repeat the test at ~5k max rpm?

 

[anickode]

Here's my theory:

Honda doesn't just slap any old thing together and call it a day. They engineer, test, reengineer, and so on till they find the best ratio of power, reliability, and cost. If it was possible to reliably get 8-10HP from a ~200cc engine at under 3600 rpm (which is the industry standard for small engines), and have it be economical and user friendly, they would be doing so.

Any modifications that increase the power output will inevitably decrease the longevity of the engine. The only 2 reasons I could think of to keep the governor on are 1) because you're either trying to prolong the life of the engine, or 2) some sort of racing league that stipulates governors must be untouched.

If you're trying to prolong the life of the engine, leaving it stock is the only way to do so. Upping the compression ratio, advancing the timing, and running a longer duration cam are about the only ways to get significant gains under 3600 rpm, and those things will most certainly shorten the life of the engine more than over-revving it by 30%.

 

[TheInspiredFool]

Can’t have your cake and eat it too, but who wants to have a cake sitting around.

If going to modify, remove the governor.
If keeping the governor, don’t modify.

Did we at least back out the throttle stop and repeat the test at ~5k max rpm?

I figured since he already spent the money and he wanted some power gain he could try to get it to work. Half of the fun is tinkering to get more power. But I agree if you don't want to tinker much, just leave it stock if the slap on kit didn't do anything for ya and you aren't much for the thrill of tinkering.

Just re-jetting the carb properly should net some positive gains over what comes in the new carb, but if your unwilling to do that then, yeah, just return it if you can. I figure since this is a DIY forum I would throw out what I think would actually be beneficial and a power gain just in case.

Here's my theory:

Honda doesn't just slap any old thing together and call it a day. They engineer, test, reengineer, and so on till they find the best ratio of power, reliability, and cost. If it was possible to reliably get 8-10HP from a ~200cc engine at under 3600 rpm (which is the industry standard for small engines), and have it be economical and user friendly, they would be doing so.

Any modifications that increase the power output will inevitably decrease the longevity of the engine. The only 2 reasons I could think of to keep the governor on are 1) because you're either trying to prolong the life of the engine, or 2) some sort of racing league that stipulates governors must be untouched.

If you're trying to prolong the life of the engine, leaving it stock is the only way to do so. Upping the compression ratio, advancing the timing, and running a longer duration cam are about the only ways to get significant gains under 3600 rpm, and those things will most certainly shorten the life of the engine more than over-revving it by 30%.

I agree on most of that for sure. The only thing is that the manufacturer has to abide by the laws of the EPA and noise ordinances that might have restrictions in some states as well as make compromises for cost and factoring in the general type of engine and it's general purpose which lead to producing an engine with a smaller footprint, that's quieter, efficient and will last forever with the distinct possibility that there will be negligent maintenance. The rpm is limited by regulations as well.

If you take the compromises away then there are definitely gaines that could be made if done properly. Maybe not huge gains, especially if you don't want to even back out a screw to get the limiter to allow a little more rpms, but you can make very effective and noticeable power gains if done properly.

Yes, more compression, switching cams and adjusting the timing would gain power, for sure. But taking an engine that will only turn 3,600rpm and adding volume to both the intake and exhaust is the wrong way to do it. Freeing up the intake and exhaust from restrictions is always great but you have to properly manage the velocity on a low rpm engine or you will never get the full potential out of the engine. You need to increase velocity and the kits instead increase flow capabilities and do very little to add any velocity.

Take any of the 6-6.5hp clone engines, add a high flow filter on a small adjustable carb, a 7" intake tube with an I.D. of .75" or smaller and a header of the same I.D. or even smaller and make it 14" long or longer and you will see gains over larger diameter intake and exhaust that just focuses on unrestricted flow. This isn't Ram Theory or Hemoltz Resonator Theory (although they might accidentally help some), it is purely about trying to get the velocity up to where it would be optimal for the engine configuration and rpm range it will be used in. The compromise between added flow restriction for more velocity will have a net gain in usuable horsepower. If you then design a system that has a proper velocity all the way from start to finish you would see a very good amount of power gain. Not huge, but definitely noticable over stock.

The kits are designed to look cool, provide an easier way to control the throttle, be universal to tons of different models and reduce restrictions while keeping it compact and easy. They know that buyers look for what they think will be the fastest. You could build a kit that provided an 18mm carb and 5/8" I.D. runner with an 5/8" exhaust header that would out-perform the gasket matching tubes and 22mm carbs but people would buy the bigger stuff because bigger is always better in most people's eyes. They offer what sells.

A stock carb, high flow air filter, silly looking small intake runner with some length to it and a silly little exhaust with some length to it. Re-jet the carb and you got more power. It won't look as cool but it will out perform any of the kits out there under 3,600rpm... And probably up to 5,000rpm.

 

[BigWes]

In his case the biggest issue with adding an intake runner is going to be trying to find a way to keep the governor linkage. We all know that ain't happening cause as soon as you move the carb out away from the engine the linkage won't reach. Anyway...if you want some bolt on power you can actually feel without doing any hardcore modifications buy a nitrous oxide kit. But even that is likely to have those consequences that Anickode mentioned in his reply. I plan on trying it some day so I'll let you know.

 

[KartFab]

I personally believe all the stage stuff is a gimmick and meant to sell parts.
There is real performance to be had out of these engines, but it can’t be found by simply bolting on a kit.

Claims
Some people say you can take a 5-6.5 stock engine and then bolt on a stage 1 kit and you get 10-12 hp. I am not one of those people because I have tested stages 1-4 on my dyno.

Real Numbers
On a briggs flathead, you see about a 0.5 hp with a "stage 1" mod.
On ~200 cc small block OHV engines, you see approximately 1.0 hp gain with a stage 1 mod.
Big block sees more than 1 hp gain with stage 1 mod.

Governor
cheap china engines like predators have weak governor return springs, so you can overpower the governor to valve float.
genuine hondas with stage 1 cannot rev past 3600-3800 from what i have seen as long as you dont bypass the governor.
There is a measurable improvement (around .2-.5 hp across the same rpm band) when bypassing the governor vs governor intact with stage 1 mods.

Conclusion
Stage 1 mods give you a 1 hp gain and no speed increase.
You want to go faster? you go beyond stage 1 or re-gear.
HP claims that go beyond this are not accurate representations of reality (which you have done with your butt dyno). If, in fact, one was to double their hp simply by doing a stage 1 mod, then one would accelerate twice as fast. The reality is you get about a 15% gain, which is actually pretty good!!!

 

[olddognewtricks]

Claims
Some people say you can take a 5-6.5 stock engine and then bolt on a stage 1 kit and you get 10-12 hp. I am not one of those people because I have tested stages 1-4 on my dyno.

Real Numbers
On a briggs flathead, you see about a 0.5 hp with a "stage 1" mod.
On ~200 cc small block OHV engines, you see approximately 1.0 hp gain with a stage 1 mod.
Big block sees more than 1 hp gain with stage 1 mod.

Governor
cheap china engines like predators have weak governor return springs, so you can overpower the governor to valve float.
genuine hondas with stage 1 cannot rev past 3600-3800 from what i have seen as long as you dont bypass the governor.
There is a measurable improvement (around .2-.5 hp across the same rpm band) when bypassing the governor vs governor intact with stage 1 mods.

Conclusion
Stage 1 mods give you a 1 hp gain and no speed increase.
You want to go faster? you go beyond stage 1 or re-gear.
HP claims that go beyond this are not accurate representations of reality (which you have done with your butt dyno). If, in fact, one was to double their hp simply by doing a stage 1 mod, then one would accelerate twice as fast. The reality is you get about a 15% gain, which is actually pretty good!!!

GREAT INFO. Thank you.

Keep in the game brother.

I ride my kart almost every day. Wish I had built this thing years ago.

 

[TheInspiredFool]

Claims
Some people say you can take a 5-6.5 stock engine and then bolt on a stage 1 kit and you get 10-12 hp. I am not one of those people because I have tested stages 1-4 on my dyno.

Real Numbers
On a briggs flathead, you see about a 0.5 hp with a "stage 1" mod.
On ~200 cc small block OHV engines, you see approximately 1.0 hp gain with a stage 1 mod.
Big block sees more than 1 hp gain with stage 1 mod.

Governor
cheap china engines like predators have weak governor return springs, so you can overpower the governor to valve float.
genuine hondas with stage 1 cannot rev past 3600-3800 from what i have seen as long as you dont bypass the governor.
There is a measurable improvement (around .2-.5 hp across the same rpm band) when bypassing the governor vs governor intact with stage 1 mods.

Conclusion
Stage 1 mods give you a 1 hp gain and no speed increase.
You want to go faster? you go beyond stage 1 or re-gear.
HP claims that go beyond this are not accurate representations of reality (which you have done with your butt dyno). If, in fact, one was to double their hp simply by doing a stage 1 mod, then one would accelerate twice as fast. The reality is you get about a 15% gain, which is actually pretty good!!!

I would be very interested in seeing some hp numbers with a longer and smaller diameter intake runner as well as header pipe. I think the torque would build faster and there would be a slight but noticable power gain up to 4,800 where it would level back off to about stock and have a more crisp response. Have you ever had a similar setup to that that you have dyno results on? I can't find any dyno results besides port matched runner and hog pipe set ups.

On a briggs flathead, you see about a 0.5 hp with a "stage 1" mod.

For the old flathead Briggs we would get an aluminum pipe and thread it for the intake, grab a carb off a little outboard engine and mate it to the intake runner pipe and then build a bracket to make sure it was secured. Then grab regular steel pipe 1' in length that would screw into the exhaust, a reducer from the next size up and the next size up pipe at 2' or whatever we had laying around. The exhaust would be pretty long. Run it, tune the carb run it more and then saw some pipe off the end of the exhaust, tune it, saw, etc until we stopped making gains. Then cut a new pipe to the length we made the best power with. They made great power and were very spunky that way. We would ream the pipes a bit and work on transition but not much else was needed. They looked stupid and you had to worry about "waging the tail" in tight turns around obstacles on some of the builds (the exhaust pipe sticking out the back would sometimes hit stuff if you were drifting) but they were screamers.

 

[BigWes]

The problem with the old Briggs flathead was that it was pretty much neutered from the factory. So anything a guy did to it was a massive improvement. Those engines came off the assembly line with only 5.5 to 1 compression ratios. That's why most of the things could run forever if they were taken care of. Honestly, that turned out to be a good thing. The problem was that they reached legendary fame because it was so easy to improve on their performance. The issue with that is the stock performance wasn't that great to start with.As much as I love a Briggs engine the fanboys totally ruin the nostalgia for me with the unending BS about these engines.

 

[TheInspiredFool]

The problem with the old Briggs flathead was that it was pretty much neutered from the factory. So anything a guy did to it was a massive improvement. Those engines came off the assembly line with only 5.5 to 1 compression ratios. That's why most of the things could run forever if they were taken care of. Honestly, that turned out to be a good thing. The problem was that they reached legendary fame because it was so easy to improve on their performance. The issue with that is the stock performance wasn't that great to start with.As much as I love a Briggs engine the fanboys totally ruin the nostalgia for me with the unending BS about these engines.

You usually got the engine for free because the engine outlasted the mechanical mechanisms they were attached to and people just gave them away or sold them for cheap. And then free scrap laying around or $10 in parts and you had stupidly cheap fun by throwing it on a gokart or minibike... especially when you could get such good performance gains over stock with such ugly red neck alterations. I think the legendary status and fanboy flashback stories have just as much to do with how cheap and plentiful they were as well as the performance and fun versus cost ratio, which is enough to make anyone love the old flatheads. I'm not sure what unending BS fanboy stories are ruining the nostalgia for you but the nostalgia for me IS the fanboy stories lol

 

[Jimmyjoe]

So, the Stage 1 kit is installed on my GX200. Everything is secure and it was installed properly....air filter, header exhaust, re-jet.

I would love your suggestions. On several tests with the Stage 1 kit, my acceleration and top speeds are virtually identical. The comparisons were all run on the same stretch of asphalt.

Do you have any ideas if something else needs to be done to gain any performance from this kit?

Well on my home made kart I have a 196 clone that will go 45mph gps app on my phone . Govener still connected. Put a vm22 carburetor with the air filter made my own exhaust pipe and flange out of 3/4" gas line welded it to a muffler that came off of a four wheeler. No kit or other mods to the engine

 

[Jimmyjoe]

Stage 1 Kit NOT Better For Me

OK, instead of guessing and asking for "help", I spent today doing my own testing.

If you want to save time and know the end-results, the stock Honda GX200 performed a little better than the same engine with a Stage 1 Kit installed (bought from Go Power Sports). My advice: save your money!

I ran two tests with my go kart and its Honda GX200. The ONLY difference in setup between the two tests was the following. Everything else was 100% identical.

Different Test Setups on the Engine:

** On the first set of runs, I ran the engine with the Go Power Sports Stage 1 Kit
** On the second set of runs, I ran the engine 100% stock original.

First Tests With the Stage 1 Kit on Honda GX200:

** Several times, I measured the time to go from point A to point B; I started from a dead start, not a rolling start. RESULT was an average of 9.1 seconds.

** Several times, I measured top speed over a set distance from a dead start. Max speed was 26MPH.

Second Tests With Honda GX200 in stock/factory condition:

** Several times, I measured the time to go from point A to point B; I started from a dead start, not a rolling start. RESULT was an average of 8.3 seconds. Exact same distance as before. BETTER than with the Stage 1 Kit by almost a full second.

** Several times, I measured top speed over a set distance from a dead start. Max speed was 26MPH, exactly the same as with the Stage 1 Kit.

Based on my results, I believe the Stage 1 Kit is purely a gimmick with only one benefit - it looks cooler than the stock parts, and depending on your point of view, it might sound cooler. Other than that, you are out $75 and annoy the **** out of your neighbors.

Really these stage 1 profamance kit are a gimmick. My kart is pulling 45mph on a stock 196 clone engine with a VM 22 carburator and a home made headder pipe and ATV muffler govener still connected.

 

[Sparkwizard]

What is your governor connected to?
Do you mean the governor parts are still inside the engine, but not connected to the carb?