super noob question about predator engine types.....

[apekillman]

I read in another thread (but now of course cant find that one), that someone mentioned that they bout the HF predator with serial number xxxxx... then someone responded by saying that that particular engine was the correct one to buy.

what is the difference between the engines besides the spark arrestor for California?

and which is better or not than another?

 

[firemanjim]

Look for model number #60363..... Its the Hemi predator, 6.5hp(212cc).....

 

[apekillman]

ok. how different / better / worse than the non-hemi are these ones?

 

[RiverSideRun]

Hemi
That is all that is needed to be said
More efficient fuel burn
Less loss of heat
Larger valves=better airflow
Few more things

 

[Denny]

Hemi head on a low compression engine running 87 octane fuel running 5000 rpm max. is hurting performance more than helping. If you were running alcohol or nitromethane and needed the extra room in the combustion chamber for all the extra fuel then, I would say hemi. But for us and our rpm range and gasoline the wedge head is the way to go. Cylinder port size and shape is way more important for us. Don't kill your self looking for the hemi headed engine which you may or may not be able to get replacement parts for in the future. not worth it in my humble opinion.

Denny

 

[firemanjim]

Hemi head on a low compression engine running 87 octane fuel running 5000 rpm max. is hurting performance more than helping. If you were running alcohol or nitromethane and needed the extra room in the combustion chamber for all the extra fuel then, I would say hemi. But for us and our rpm range and gasoline the wedge head is the way to go. Cylinder port size and shape is way more important for us. Don't kill your self looking for the hemi headed engine which you may or may not be able to get replacement parts for in the future. not worth it in my humble opinion.

Denny

Hmmm? Goes against everything I've read on this forum...... O well, to each his own. Regardless, any of the 212's(predators) are great kart engines. If you get a hemi you get a hemi. If not, or well.... It's still gonna haul butt.....
EDIT the hemi is suited to the engine builders, looking for all out performance. In stock form, it runs great. Modified, runs a lot better...... LoL
I only run 93 octane, or better, in my toys. It's not like I'm filling up a 40 gallon truck tank. And my gx runs over 6000 rpm, so maybe we just don't see eye to eye..... ?

 

[apekillman]

so, in a blind test, would the average dork (me) be able to tell the difference in performance between the models?

 

[Poboy kartman]

No....

 

[Denny]

Hemi engines do not like low compression ratios or non performance applications. Remember the early hemi engines of the 50's Chrysler kept upping the cubic inches from 331 to 392 for more power. In 1960 the hemi engine was gone and in came the wedge heads because Chrysler figured out on low performance low compression engines the hemi head actually hurt potential performance due to the lack of a squish area in the chamber. The squish area is the flat part of the chamber usually even with the deck surface of the head. When the hemi came back in 1964 it was a pure performance engine period! No more low compression ratios. No more conservative camshafts and built to rev over 6,000 rpm. We can thank the Ramchargers racing team for being the guys to mostly figure this all out (all Dodge engineers). Due to the squish area only having 60-120 thousandths clearance (on average) between the crown of the piston and the head you can see why nitro-methane is not the fuel of choice for wedge headed engines. A little liquid fuel in there and you have a hydraulic situation.

Denny

 

[Scout]

A friend of mine just swapped in a non-hemi predator in his kart, with a TC. He bypassed the governor and going downhill it has no top end. It just keeps going faster and faster. Based on that, and my experience with a hemi predator, I'd say you probably won't see a real difference.