DominatorRc

Just wanted to make a clarification. You may have noticed in my "1/5th scale truck vote" thread that the RH503 4x4's would be coming out with the CY29cc motor. I spoke with River Hobby today and that is no longer the case. They are now equipping the 4x4's with the CY27cc which is the same motor used in the 2x4's. I expressed concern that the 29cc might be the better motor for the 4x4 because normally the larger the cc's the more bottom end torque, with a slight sacrifice on the top! And with 4x4, the extra cc's would help overcome the extra drag! They explained to me that the 29cc is not putting out as much power as the 27cc. I asked if the 27cc bogged a bit on the bottom end and was told it actually took off faster and had a better top end than the 29cc. And until CY makes the needed improvements to the 29cc, they were sticking with the 27cc. I do know my 2x4 with stock gearing at 7:57:1 runs 46mph on GPS, so I would hope the 4x4's will run quite well also being geared at 8:05:1, which is quite a bit higher gearing than most other 4x4's. The 27cc is very strong in the 2x4's, I just hope it makes a strong showing out of the hole in a 4x4! Will let you know after I receive the 4x4 sample!

Foxy

Although torque is needed for 4x4 because they are driving all 4 wheels, the main loss through the 4wd drivetrain, is topend.

I went from a (admittedly poor) 28cc, to a 'special' 23cc in my Smartech 4wd buggy, and the difference was astonishing, not only better out of the hole, but double the top end. It's hard to predict the gains from increasing or decreasing CCs on a 4wd car. It depends what you want from the car.

In any case, I agree with Wind on this one, short stroke engines (27cc or less), still put out enough low end, and rev much better (in general) than longer stroke (+1, +2 29cc, 30.5cc etc). A lot of it is down to taste though. Some want to see their car going really fast. Others want to see shin busting rooster tails. I belong to the former category.

Finally, it's not that big a deal what engine comes with an RTR, especially if it's a CY, cos headkits can be bought to change the cubic capacity to whatever you want for very little money. Nobody expects miracles from RTR engines, but it is a bonus when they do perform right out of the box.

splcrazy

if i were you i would find out if they make a 27cc raceported head kit , then install a stuffed crank , so keep the piston just replace the head for a race ported head and install a stuffed crank , it will be revvingly snappy . also check to see if the head is cut to allow for a +2mm stuffed stroker or they do also make stock length stuffed cranks .

Kemo

Go with a 27 cc

jasrx

im kinda tossing up between the ESP Modified & ESP Fully Ported 30.5cc CY31RC Engine , or ESP Modified & ESP Fully Ported 27.2cc Zenoah Engine
i cant decide i want more low down grunt [ i have the standard 26cc zen ] but i want decent rpms too .... i have less then a week to decide ..

Foxy

ESP 27.2 and Dom torque pipe will give you what you seek!!

Did you see my post in your other thread in response to you thinking that the torque pipe was incompatible with the wheely bar? I'm running wheely bar, torque pipe, wing AND silencer successfully, but like I said, it's a monster, not a stadium, so I'm not sure if you maybe facing different problems...

jasrx

yeah i did see foxy , and yeah the dom would give me huge issues with the rear body shell mounting . but i guess i could mod [laser cut new mounts up out of alloy at work] hmmmmmm

rckiwi

Interesting! no 29cc now! still will be good with the 27cc they have plenty of power/torque, but I still prefer a good Zen 23cc they still kick arse!

splcrazy

ive got the ESP raceported 36mm headkit , its power like youve never felt like before , the 29cc 35mm that i was running before had power like it was pretty darn good , but when i installed the ESP 36mm raceported head and run it , it was scary man i first just opened the throttle bit by bit slowly and it was crazy untill i opened it fully and crikey all i can say is that there is just no comparison to the smaller displacements lol the 36mm 30.5cc ESP raceported heads are beastly , definatly buy one and try it

bajamaniac69

will wait for 30.5 ZEN motor head kit coming soon[X(]

Kemo

what needs that much torque??? Do you plan to ride? Thats just insane amounts that some people are able to work into these engines, and kudos to them!