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ebonyandivory
ebonyandivory PowerDork
10/29/18 5:40 a.m.

In reply to AwesomeAuto :

Are you testing them inside with some control over ambient temperatures? Or are you forced to test outside?  

Edit: it looks like you have an unheated garage from your last post

I’m totally amazed at the horsepower increase in colder air. I know the whole incoming air being colder/denser but would never have expected the cooler engine to have such a huge increase in power!

AwesomeAuto
AwesomeAuto Reader
10/29/18 6:51 a.m.

Its a heated garage, but its an attached garage. I have to keep all of the doors wide open or else the house smells like gas fumes.

 

Yes, a much cooler engine has been having a big increase on power in my garage. Its just the design of air cooled engines. The important thing is the oil temps. Even though the oil temps are the same, the cylinder head has been running much cooler thanks to the combination of cooler temps and strong breeze we've been having. I can install a cylinder head temperature probe and double up the correction factor so its multiplies by % for air temp/pressure/humidity and then multiplies again by % based on temperature alone.

Likely won't, but it would be interesting to see the results.

buzzboy
buzzboy Reader
10/29/18 7:27 a.m.

In reply to ebonyandivory :

Engine Masters did that recently on an episode. Pretty interesting. They made pulls at their usual coolant temp of (iirc) 120F then again at full operating temp. They did it to show how you'll never recreate engine dyno HP numbers.

FuzzWuzzy
FuzzWuzzy Reader
10/29/18 8:21 a.m.

I have nothing of value to contribute beyond saying this is so damn cool.

Also, I have two weed whacker engines and three lawn mower engines ( one being a GCV160; other two no idea yet) and seeing this makes me wanna finally do something with them.

AwesomeAuto
AwesomeAuto Reader
10/29/18 9:55 a.m.
FuzzWuzzy said:

Also, I have two weed whacker engines and three lawn mower engines ( one being a GCV160; other two no idea yet) and seeing this makes me wanna finally do something with them.

It makes me want to modify my mower. That thing has no power in tall grass even with a sharp blade. If it ends up looking beneficial to do a cheap muffler replacement or something for under $10, I'd like to know what works best.

iceracer
iceracer UltimaDork
10/29/18 2:56 p.m.

small engines have fixed ignition timing.

 we used to do a thing with the point spring on the kart engines.

O f course points are ancient history.

californiamilleghia
californiamilleghia Reader
10/29/18 5:40 p.m.

if you are doing an oil test can you do one pull with 50 weight oil  just to see if you lose HP having too thick of oil .....

at one time 50 weight was used a lot in air cooled VWs  that were run in 100F plus  weather....

Brett_Murphy
Brett_Murphy UltimaDork
10/29/18 11:56 p.m.

Nice work, that's impressive.

 

AwesomeAuto
AwesomeAuto Reader
10/30/18 6:28 a.m.
californiamilleghia said:

if you are doing an oil test can you do one pull with 50 weight oil  just to see if you lose HP having too thick of oil .....

at one time 50 weight was used a lot in air cooled VWs  that were run in 100F plus  weather....

I'll do a thick oil weight test, but its pretty much guaranteed to lose power. I've seen it on cars going from 5w-20 to 20w-50 in my turbo cars.

44Dwarf
44Dwarf UberDork
10/30/18 7:23 a.m.

If you have more data slots available you might want to track Spark plug temp (CHT) and Exhaust gas temp (EGT)  if you see CHT going up and EGT going down bad things are going on in your burn...  I know some kart guys will slot the whole holding the mag down and dial in the timing they want.  It's best to do that on a milling machine with a rotary table so you don't have to worry about the mag touching the flywheel if it come loose, but even easyier is offset keys.

44Dwarf
44Dwarf UberDork
10/30/18 7:30 a.m.

Not sure if you've been over to John Copeland's site Foxvalley karts but here's a link to his articles there's some really good info there.  That said there is nothing like doing it for yourself and having the satisfaction of gaining that last leg up over your buddy lined up next to you.  ;)

 

http://www.foxvalleykart.com/articleindex.html

 

AwesomeAuto
AwesomeAuto Reader
10/30/18 7:37 a.m.
44Dwarf said:

If you have more data slots available you might want to track Spark plug temp (CHT) and Exhaust gas temp (EGT)  if you see CHT going up and EGT going down bad things are going on in your burn...  I know some kart guys will slot the whole holding the mag down and dial in the timing they want.  It's best to do that on a milling machine with a rotary table so you don't have to worry about the mag touching the flywheel if it come loose

I've debated making an ignition controller to control spark based on RPM. It wouldn't be too terribly difficult. The main issue being that I would have to use an igntion coil with no way to generate an electric charge without a battery. Not an issue for dyno and testing purposes, but not easily replicated in the real world.

Tyler H
Tyler H UltraDork
10/30/18 7:49 a.m.
ebonyandivory said:

In reply to AwesomeAuto :

Wouldn’t it be great to see if a 6.5hp Predator is actually ​​​​​ 6.5hp?

Somewhat off topic but I have a 13hp B&S for one of my Karts. Can’t wait

This is awesome.  The only anecdote I have is that the $80 (with super coupon) 212 that I put on my 'kids' cart went a gps-verified 54mph on my long driveway...or about 23mph more than the tired Briggs that it replaced.  8hp feels about right to my butt.  

ebonyandivory
ebonyandivory PowerDork
10/30/18 8:02 a.m.

In reply to Tyler H :

That’s screaming fast! What’s the sprocket situation?

AwesomeAuto
AwesomeAuto Reader
10/30/18 8:18 a.m.
Tyler H said:
ebonyandivory said:

In reply to AwesomeAuto :

Wouldn’t it be great to see if a 6.5hp Predator is actually ​​​​​ 6.5hp?

Somewhat off topic but I have a 13hp B&S for one of my Karts. Can’t wait

This is awesome.  The only anecdote I have is that the $80 (with super coupon) 212 that I put on my 'kids' cart went a gps-verified 54mph on my long driveway...or about 23mph more than the tired Briggs that it replaced.  8hp feels about right to my butt.  

Mine goes 44 with the governor and tops out pretty quick. I could probably have stretched it over 50 just by switching from a 12 tooth to 16 tooth clutch.
It did 50 when I removed the governor on the 12T sprocket. That extra 1000 RPM made a difference. Not a peak power difference, but definitely a speed difference.

Amazing value for the dollar.

 

ebonyandivory
ebonyandivory PowerDork
10/30/18 8:30 a.m.

In reply to AwesomeAuto :

My 13hp engine from my snowblower runs a 12v headlight. Could that be used for ignition?

AwesomeAuto
AwesomeAuto Reader
10/30/18 8:44 a.m.
ebonyandivory said:

In reply to AwesomeAuto :

My 13hp engine from my snowblower runs a 12v headlight. Could that be used for ignition?

Possibly. If its able to generate electricity, its able to run a battery. It MAY be enough to charge an ignition coil but I don't know the exact details.

Either way, with an ignition coil and a source of power, all you would really need is a trigger wheel mounted somewhere so that RPM and crank angle can be read and a spark can be timed.

44Dwarf
44Dwarf UberDork
12/5/18 9:22 a.m.

This threads got me thinking of digging out my motorcycle water brake dyno made in the late 60's by Patraco in California.  I've got no paper work it.  I have used it in the past but not for 15 or so years...  It has a hydraulic piston off a torque arm that goes to a pressure gauge with breadboard on the back and a tach off the rollers that go to the HP meter.  I'd like to keep all the OEM just for giggles but want to add modern recordable electronics and be able to track the Innovative wide band unit i have. (small round dash board unit that i use as portable with a small battery)

What software package are you using ect.

 

Thanks 44

Tyler H
Tyler H UltraDork
12/5/18 10:05 a.m.
ebonyandivory said:

In reply to Tyler H :

That’s screaming fast! What’s the sprocket situation?

I don't recall.  I did switch to a lower tooth count sprocket on the drive axle because I was slipping the chain and chewing teeth on the original one.  Probably contributes to the higher top speed.

BrianPaul69
BrianPaul69
6/30/20 11:14 p.m.

Hello, I just found your link and THIS is EXACTLY what I need to build. I'm starting to build / fabricate parts for XR CRF 80 / 100cc bike sand like you I NEED to know if my mod is good or not. What mods work together what ones don't etc. What you have here is perfect for what I need. Could you give a list of parts / electronics that are needed ( pump, torque sensor, software ) so we can source them out? I really excited about this because once you have the basic setup put together it can be altered for any engine or bike frame. The chain just needs to be connected to the engine, the engine can still be on the bike and just connect the swingarm and chain.

 

Fuel injection / ignition stand alone 

https://www.ebay.com/itm/motorcycle-ATV-scooter-buggy-moped-UAV-EFI-engine-Electronic-Fuel-Injection-kit/273127447029

 

and this

 

https://www.ebay.com/itm/AISIN-AMR300-Roots-supercharger-Compressor-blower-booster-Kompressor-turbine-AMR/273886557521

 

Thank you for this you've made my life much simpler :)

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