Basic Upgrades for a Predator 212

[derrick81787]

Hello again.

If everything I've read is correct, the easiest and most cost effective upgrades for a Predator 212 are a new air intake, new exhaust header, and a new carb jet. Is that true? If so, does anyone know approximately how much power I would gain or have a recommendation for specific parts that are known to work well but don't cost too much?

I keep going back and forth on how I want to upgrade my kart. I could still use larger tires, but adjusting the suspension all the way really did help a lot. Then I was thinking that it might be a bad idea to upgrade the tires and adjust my gearing and to then upgrade the engine afterward because that might affect my gear selection. I might be better off upgrading the engine first.

Thanks.

 

[Poboy kartman]

You're screwing up at LEAST two ways:

Thinking that slightly upgrading the engine is going to make ANY difference in gearing.

And secondly....starting a new thread...so nobody has a clue what kart, minibike, or bicycle you're talking about.

 

[derrick81787]

Okay, thanks. I think you answered my biggest question, and next time I'll keep to the same thread.

 

[bob58o]

People claim near 10 HP with governor removal, Air filter adapter and air filter, exhaust, offset timing key, gx140 emulsion tube, and something like a .037 - 0.38" main jet.

Some didn't like the E-tube. You should be fine with the stock one. Just add 6-8 degree offset flywheel key to your list.

 

[Poboy kartman]

WOW! A Cliff Notes version! ^^^^^^

 

[ezcome-ezgo]

That was alarmingly concise.

 

[bob58o]

That was alarmingly concise.

Somebody slap me!

---------- Post added at 04:10 PM ---------- Previous post was at 03:59 PM ----------

Honestly my favorite responses on here (I remember seeing them often, but forgot who it was),
took a paragraph or two post with some questions tossed in and answered like....

"Yes
Yes
No
Maybe
Yes
No
In a way
No

Got it?"

 

[Poboy kartman]

I got it...but how do you expect anybody else to.....when your posts read like ...the Green Mile....and...we're all just wantin to go to the Chair, Boss....'cause we needs some relief! '

 

[chancer]

People claim near 10 HP with governor removal, Air filter adapter and air filter, exhaust, offset timing key, gx140 emulsion tube, and something like a .037 - 0.38" main jet.

Some didn't like the E-tube. You should be fine with the stock one. Just add 6-8 degree offset flywheel key to your list.

I agree with all this... From what I have read here. Except the 6-8 degree offset flywheel key. This has been new info as of late and mostly on GAB type builds.
Someone besides Bob tell me if that is needed with "only" the other mods Bob correctly listed.

 

[Jrgunn5150]

I agree with all this... From what I have read here. Except the 6-8 degree offset flywheel key. This has been new info as of late and mostly on GAB type builds.
Someone besides Bob tell me if that is needed with "only" the other mods Bob correctly listed.

I had all that stuff except the key, maybe I would have been happier with it? Idk, it didn't explode or anything.

 

[Kentucky Boy]

Best upgrade I did was remove the oil sensor switch. All that horse powers no good if the thing cuts off around every turn or bump.

 

[chancer]

Best upgrade I did was remove the oil sensor switch. All that horse powers no good if the thing cuts off around every turn or bump.

I do not think he meant that basic. LOL

 

[Kentucky Boy]

Gotta start somewhere

 

[bob58o]

I agree with all this... From what I have read here. Except the 6-8 degree offset flywheel key. This has been new info as of late and mostly on GAB type builds.
Someone besides Bob tell me if that is needed with "only" the other mods Bob correctly listed.

It comes with the OMB Kit, it also was 0.036 - 0.037" main jet with the kit.

I'll PM you my full report in the morning. Lol

 

[chancer]

I'll PM you my full report in the morning. Lol

I do not have that kind of band width.

 

[Poboy kartman]

Bob's front door house key is offset 8°.....

 

[Jrgunn5150]

How I envision Bob's front door,

 

[chancer]

OMG... Perfect

 

[bob58o]

I agree with all this... From what I have read here. Except the 6-8 degree offset flywheel key. This has been new info as of late and mostly on GAB type builds.
Someone besides Bob tell me if that is needed with "only" the other mods Bob correctly listed.

A lil input from our overseas oversee-er....

http://www.diygokarts.com/vb/showthread.php?t=23928

and where i was going to go......

ASSUMING 2mm FROM PLUG ELECTRODE TO PISTON NEAR TDC.
ASSUMING 1.35 METERS / SECOND FLAME PROPAGATION

I'll spare the math that shows at 5000 RPM, the crank turns ONE degree every 0.033 milliseconds..

I spare the part where i guess the flame propagates at 1.35mm per millisecond in the combustion chamber.

I also guess at Piston to Plug electrode distance at 2 mm near TDC.

2mm / 1.35mm/ms = 1.48 milli-seconds
1.48/0.033 = 45 degrees crank rotation.

It takes 45 degrees of crank rotation to ignite all the fuel in the chamber and pressure to build to max.


For example if spark occurred at 25 degrees before TDC, Peak Pressure happens at 20 After TDC.

If you advance to 32 degrees before TDC, Peak Pressure happens at 13 degrees after TDC.

I've read 15 degrees ATDC gives a good piston to CONROD angle to promote crank rotation. Advance too much and the force goes straight down the rod (it doesn't help turn it). Retard it, and the pressure is reduced.

A 6 degree key (30-31 degrees BTDC ignition) puts you right at 15 degrees ATDC for max pressure. (The Sweet Spot)

I made assumptions about the speed of flame propagation (turbulent) and the distance from the piston to plug. (0.025" deck height, 0.045" gasket).

My assumptions make the actual calculation impossible. The 1.35mm per milli second turbulent flame propagation speed, I can reference, but it says 1.35 - 2.2.

The 2mm piston to plug distance, I picked to make the math work (but it kinda makes sense).
http://www.superhonda.com/forum/f55...ming-writeups-i-have-ever-come-across-268106/

 

[ezcome-ezgo]

You're GAB'ing up this guy's thread.