RCU Forums

RCU Forums (http://www.rcuniverse.com/forum/)
-   HPI Monster Truck Forum (http://www.rcuniverse.com/forum/hpi-monster-truck-forum-250/)
-   -   which engine is better: k4.6 or F4.6? (http://www.rcuniverse.com/forum/hpi-monster-truck-forum-250/6099790-engine-better-k4-6-f4-6-a.html)

hansdava 07-11-2007 07:13 PM

which engine is better: k4.6 or F4.6?
 
out of the 2, which one is better?, faster?, and more durable?, in all what is the diffrence between the 2 of them?
hpi claims:
k4.6 = 2.9 HP
F4.6 = 2.9 HP

myrcsupply 07-11-2007 08:42 PM

RE: which engine is better: k4.6 or F4.6?
 
i personally would go with the K4.6 the design is better with the one-way inside, it seems to last longer.

The removal of the button head makes for less parts, and seems to seal really well as long as its clean.

the new F4.6 looks to be a remake of the .25. completely identical inside. i found alot more leaks with that engine, so im assuming we should see the same with this one.

if you can, go with the k4.6 or the HO version found in the hellfire.

hansdava 07-11-2007 10:54 PM

RE: which engine is better: k4.6 or F4.6?
 
thanks for the info.......but still need to know more, u know , u said k4.6 is better in durability, but what about speed? which one is faster since both have the same horsepower(2.9HP)?................and guys besides this questions, i'd like to know what is the faster engine i could put in my savy and where i can find it cheap, also all i do is bashing with it and big jumps.................
P.S. still need to know which one is faster k4.6 or F4.6.........

NitroVenom 07-11-2007 10:59 PM

RE: which engine is better: k4.6 or F4.6?
 
Axial .28, sts 28 or sts 30. These are all in the $120-140 range and are the some of the fastest out there.

ThunderbirdJunkie 07-11-2007 11:40 PM

RE: which engine is better: k4.6 or F4.6?
 
what NitroVenom said. screw the factory HPI engines...tehy're all overpriced for what they are, even if they are halfway decent engines.

SpikeX 07-12-2007 12:06 AM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: hansdava

what about speed? which one is faster since both have the same horsepower(2.9HP)?
I think the F4.6 would be faster because it revs higher. The K4.6 produces 2.9HP @ 29,000RPM, and the F4.6 produces 2.9HP @ 32,000RPM.

MasterMechainc5 07-12-2007 01:00 AM

RE: which engine is better: k4.6 or F4.6?
 
Quote:

what NitroVenom said. screw the factory HPI engines...tehy're all overpriced for what they are, even if they are halfway decent engines.
yup, get a axial there very reasonably priced compared to HPI;) I mean what would you rather have a hpi k4.6 for $189.99 or a Axial .28 for $119.99 its the same engine except the axial looks better[8D] (dont care for purple heads), you could even get the awesome Axial .28RR for less then the k4.6 at $174.99 and it will smoke the k4.6 and looks cooler:D

SpikeX 07-12-2007 02:02 AM

RE: which engine is better: k4.6 or F4.6?
 
Yeah, the K4.6 is rock-steady reliable and easy to tune, but it is a little lacking in the power department. A new K4.6 from the LHS costs around €250, whilst a new LRP Z.28R Spec. 3 costs €150. And the LRP is better than the K4.6 in every department.

Ev1er 07-12-2007 05:09 AM

RE: which engine is better: k4.6 or F4.6?
 
The F4.6 has 2.95 hp and the K4.6 has 2.9 hp:)

SpikeX 07-12-2007 05:35 AM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: Ev1er

The F4.6 has 2.95 hp and the K4.6 has 2.9 hp:)
That's not what the HPI website says. [&:]

I know the K4.6 makes 2.9hp and the K4.6 HO makes 2.95hp...

SAVAGEJIM 07-12-2007 08:36 AM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: hansdava

out of the 2, which one is better?, faster?, and more durable?, in all what is the diffrence between the 2 of them?
hpi claims:
k4.6 = 2.9 HP
F4.6 = 2.9 HP
As far as durable, my personal experience with my K4.6 engines are not bad. I have run nearly a dozen of gallons (maybe more) through each of my K4.6s before they needed a rebuild. Great low to mid RPM power, but not so good top end.

The F4.6 I believe will be a better performer especially on the higher RPM side when compard to the K4.6. The factory cut flow channels on the lateral ports help promote higher RPM fluid flow. The turbo scallop cut on the crank face helps mix the fuel-air charge better; this promots a little more power throughout the entrire RPM range. Performance wise, I say the F4.6 would probably be better. That is, if its timing profile is a decent design to take advantage of the internal mods.

As for the durability of the F4.6, only time will tell. Once more and more people break the 10 gallon mark on their F4.6 engines will its durability be revealed.

black mamba 07-12-2007 12:30 PM

RE: which engine is better: k4.6 or F4.6?
 
Neither of those engines put out 2.9hp...those are advertised numbers. A dyno that measures real world power and torque will cut those numbers in ~half. As for which one is better, I'd say the K4.6. Much better carburetor and a better scalloped head. I can't believe HPI put that junk "purple" carb on the F4.6 after all the problems they have had with it over the years.[8D]

hansdava 07-12-2007 01:47 PM

RE: which engine is better: k4.6 or F4.6?
 
can anybody post a link toward the axia engines, i mean the cheapest places to get them, btw thanks for the info.....

black mamba 07-12-2007 05:23 PM

RE: which engine is better: k4.6 or F4.6?
 
ebay is the cheapest place to get a Axial.

SAVAGEJIM 07-12-2007 05:53 PM

RE: which engine is better: k4.6 or F4.6?
 
True, 2.9HP is an absolute lie. These egine probably only produce 1.1 to 1.2 BHP once corrected for real world conditions.

hansdava 07-12-2007 06:35 PM

RE: which engine is better: k4.6 or F4.6?
 
need more info..anybody else.............

SAVAGEJIM 07-12-2007 07:07 PM

RE: which engine is better: k4.6 or F4.6?
 
1 Attachment(s)

Quote:

ORIGINAL: hansdava

need more info..anybody else.............
Here is a pic of teh F4.6 sleeve, scoll down to mid page.
http://www.hpiracing.com/products/en/867.html

Below is a pic of the K4.6 sleeve

black mamba 07-12-2007 09:29 PM

RE: which engine is better: k4.6 or F4.6?
 
http://cgi.ebay.com/HPI-SAVAGE-X-4-6...QQcmdZViewItem

That's pretty steep for what it is. For the money, I'd ditch any HPI 4.6 plans you might have and get yourself a Axial .28 instead. It's a better engine that puts out more power and torque and isn't as expensive.[8D]

NitroDemon18 07-12-2007 09:41 PM

RE: which engine is better: k4.6 or F4.6?
 
For Axial engines new go to towerhobbies. There probabily the cheapest for Axials.

SAVAGEJIM 07-12-2007 09:47 PM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: gravediggerracing

http://cgi.ebay.com/HPI-SAVAGE-X-4-6...QQcmdZViewItem

That's pretty steep for what it is. For the money, I'd ditch any HPI 4.6 plans you might have and get yourself a Axial .28 instead. It's a better engine that puts out more power and torque and isn't as expensive.[8D]
This is so true. I do not know why, the K4.6 and F4.6 are way TOO expensive when the Axial alternative (and other engines) are way better and cheaper. That is lame.

myrcsupply 07-13-2007 12:46 AM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: NitroDemon18

For Axial engines new go to towerhobbies. There probabily the cheapest for Axials.

We have them for less...:D


also, you really cant go by the specs posted by the manufacture. becuase they dont give us the important information that is needed for the engine to prodcue the spec'ed numbers. So lets stop thinking about that.

If your looking for an HPI engine, either is good, you will see more speed by changing the spur gear and clutch bell combo (see HPI site) than you will in difference between the two HPI engines. I see some K's that outperform in a drag, and also vise versa. so its really all about your setup and your tuning ablilty.... and again, we stock all those engines in our warehouse's @ a great price.

hope this helps.

black mamba 07-13-2007 01:54 AM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: NitroDemon18

For Axial engines new go to towerhobbies. There probabily the cheapest for Axials.
Not really. You can find them cheaper elsewhere.[8D]

hansdava 07-13-2007 03:07 PM

RE: which engine is better: k4.6 or F4.6?
 
thank u guys for the info, but one last question the axial engines can be mod... to roto start or they are only pull start?

SpikeX 07-13-2007 03:11 PM

RE: which engine is better: k4.6 or F4.6?
 

Quote:

ORIGINAL: hansdava

thank u guys for the info, but one last question the axial engines can be mod... to roto start or they are only pull start?
I belive you can use the Roto Start Backplate for the K4.6 on the Axial .28 Spec 1, since the engines are very similar. Not sure about the .28RR though...

RazeRacer 07-13-2007 04:02 PM

RE: which engine is better: k4.6 or F4.6?
 
The only reason I have a K4.6 In my savage is because I got it for 90.00 brand new off ebay.

May I remind you its been ported and polished, also.


All times are GMT -8. The time now is 01:45 PM.