Any CEN GST 7.7 Opinions??

[Knightrider955]

I did get it started finally. Started hard. I think my drill was a little slow though. Even after the motor was warm, if I tried to restart it, I had to crank and crank. Once it starts it idles real nice. A lot of bad looking gas and oil can out the pipe on initial start up. The longer I ran it the better it idled. Pulled the throttle servo out of my part ST-15 rig. Gonna put it in the CEN latter and see if it fixes my glitch issue. Hope its strong enough to pull that throttle return spring. We'll see...

 

[smittyzz]

Glad you got it running and are starting to gain some ground to enjoying it!
You sound like Me when it comes to all this. I have to order all online and it sucks when I'm waiting on a part mainly because I'm inpatient and partly because I usually can't run without the part, #o I'm starting to bulk order just to have backups Lol
And I'm not afraid of digging into someone's project and making it a nice rig as long as it isn't another 200 to make it nice.
Right now I'm working on customizing an on road car I got to rake a center diff to be able to use again because there's no support at all and the spur gear is toast on both gears. I'm putting a locked center diff in and moving the engine mount plates a little forward so it can reach the spur gear.
Just need to drill 6 holes. I'm hoping she works good after as it was the main reason I bought this package of stuff. But did make my money in everything else

 

[Knightrider955]

Glad you got it running and are starting to gain some ground to enjoying it!
You sound like Me when it comes to all this. I have to order all online and it sucks when I'm waiting on a part mainly because I'm inpatient and partly because I usually can't run without the part, #o I'm starting to bulk order just to have backups Lol
And I'm not afraid of digging into someone's project and making it a nice rig as long as it isn't another 200 to make it nice.
Right now I'm working on customizing an on road car I got to rake a center diff to be able to use again because there's no support at all and the spur gear is toast on both gears. I'm putting a locked center diff in and moving the engine mount plates a little forward so it can reach the spur gear.
Just need to drill 6 holes. I'm hoping she works good after as it was the main reason I bought this package of stuff. But did make my money in everything else

Looks like a cool project!! Goodluck!! I'm the same way as far as projects go. I'll just make my rig into whatever I want it to be!

 

[Lstxxl2012]

The 7.7 engine has mostly low end torque hence the 5hp @ only 23,000, I have notice that my nemesis is geared relatively high to make up for the lack of crank speed. It is a pretty awesome engine if you know how to tune it right.

---------- Post added at 10:42 AM ---------- Previous post was at 10:40 AM ----------

When people neglect there Rc's and they are not running and covered in old fuel, these are the best one. The Nemesis I acquired was the same way. Oh for your servo issue, its the fail safe, mine was bad. It removed it and put a new one in and problem is cured. Did your truck have the airtronics radio or the toy looking 2.4ghz.

 

[Lstxxl2012]

Hello, My Nemesis was the same way, the fail safe was my problem child on my truck, try by passing it and see if that helps. Also are you using the 4 cell alkaline pack because that was another one of my issues, I replaced it with a 5 cell 1600mah pack and now the radio is solid no glitches at all. If you have any other issues I probably ran into the same. I didn't even bother starting mine, I stripped it down to nothing cleaned all of the crap off, including the engine and reassembled it. Its like a new truck. I love this things its so bad ass..

 

[Sixtysixdeuce]

The 7.7 engine has mostly low end torque hence the 5hp @ only 23,000

They are nowhere near 5HP. The one I bought was worn out, so I rebuilt it. Brand new piston, rod & sleeve. Broke it in, carefully tuned it. Still didn't make as much power as either my LRP ZR.32 or my OFNA Force .32. Ended up selling it at a loss and using an OFNA .32 in my Losi MGB.

 

[Lstxxl2012]

You should post some pics of you truck.

 

[Knightrider955]

Hello, My Nemesis was the same way, the fail safe was my problem child on my truck, try by passing it and see if that helps. Also are you using the 4 cell alkaline pack because that was another one of my issues, I replaced it with a 5 cell 1600mah pack and now the radio is solid no glitches at all. If you have any other issues I probably ran into the same. I didn't even bother starting mine, I stripped it down to nothing cleaned all of the crap off, including the engine and reassembled it. Its like a new truck. I love this things its so bad ass..

I assume when you say failsafe that you are referring to that large return spring. I ended up replacing the throttle servo with a different one and no more glitching. Although the servo I'm currently using is a little weak it does the job. My truck came with the Skyion DSX radio. For an AM radio it has llots of cool features and LCD screen. I'm using the standard 4 cell pack that it came with for now.

---------- Post added at 6:25 PM ---------- Previous post was at 6:19 PM ----------

They are nowhere near 5HP. The one I bought was worn out, so I rebuilt it. Brand new piston, rod & sleeve. Broke it in, carefully tuned it. Still didn't make as much power as either my LRP ZR.32 or my OFNA Force .32. Ended up selling it at a loss and using an OFNA .32 in my Losi MGB.

I'm sorry you didn't have luck tuning that engine properly. I dialed mine in pretty decent. The one in my rig is a torque monster!! Its not a screamer like some of the smaller big blocks but it wasn't designed to be. It was designed with power down low. Wont win any drag races but would be top dog at tug of war! I'm good with it so far. Although now you have sparked my curiosity a little bit. I I find a deal on a force .31 I might try it out just for fun.

 

[Sixtysixdeuce]

I'm sorry you didn't have luck tuning that engine properly. I dialed mine in pretty decent.

Did you expect me to perceive this as anything other than an insult?

You can't tune power out of an engine when the design simply does not permit. I'm hardly the only one here who recognizes that Corsa engines are pretty low on the quality & performance totem pole.

I'm glad you're happy with the 7.7, but trust me; when you get all growed-up and gain some experience with quality big blocks, you'll look back and shake your head at the notion that the NX-76 is a "torque monster".

 

[Knightrider955]

Did you expect me to perceive this as anything other than an insult?

You can't tune power out of an engine when the design simply does not permit. I'm hardly the only one here who recognizes that Corsa engines are pretty low on the quality & performance totem pole.

I'm glad you're happy with the 7.7, but trust me; when you get all growed-up and gain some experience with quality big blocks, you'll look back and shake your head at the notion that the NX-76 is a "torque monster".

Ok then tell me what big block will bolt right into my CEN and out perform the 7.7. I apologize for you not getting as lucky as I did with tuning it and that's an insult??

 

[Sixtysixdeuce]

Ok then tell me what big block will bolt right into my CEN and out perform the 7.7. I apologize for you not getting as lucky as I did with tuning it and that's an insult??

Tuning isn't luck.

As for drop-in engines, well, there are none. The NX-76 has proprietary everything. I went to great lengths mounting it in my Losi MGB, including machining custom mounts, turning flywheels on a lathe and machining the back plate to allow clocking of the pull start, only to be sorely disappointed by a huge engine that would barely out-perform the stock sport .26. I really wanted to like this engine, believe me. It looked bad-@$$ sitting on that truck, but was all show and no go. On top of being anemic for it's huge size, it's low redline made it impossible to have a properly-functioning 2-speed transmission on that truck. It was either in second all the time, or didn't shift out of first until absolute max RPM.

 

[1mtx1]

I seen one of these many years ago and i wanted it bad. I was just looking around on Ebay for one. I really want one but i just want to make sure there is parts for it around . Some one help me out here. What is the price to pay for a used one? I kinda am scared of doing it on line but i will not see one around town .

 

[Knightrider955]

Well you were putting a engine that revs lower and makes power down low into a truck that was geared for a engine that's a screamer. I think putting a higher reving .31 race motor in a CEN would also have disappointing results. It would probably shift too early before the engine is in the power band. I talked to a guy on another forum that has mastered the art of waking up that nx motor. It does involve adding some additional porting but he has all the specs and info to do it. I'm kicking that Idea around....

 

[Knightrider955]

I've made some other discoveries. My steering is very weak. Found a Traxxas 2055 servo in there. Its a measly 84 oz at 6V. Not gonna do the trick. The Tower hobbies servo I put in for the throttle is only a 40 oz so its not the greatest but it works for now. So I'm going to buy a high torgue steering servo and move that traxxas to my throttle/brake.

---------- Post added at 7:37 AM ---------- Previous post was at 7:35 AM ----------

There are plenty of parts available. Theres a pretty decent aftermarket as well. They go anywhere from 200-400 on ebay when you find one.

 

[Knightrider955]

The Big Dog!! Next to my old ST-15.

 

[Knightrider955]

Well my new 133oz servo came today. And although it is a improvement over the 80oz traxxas servo, its still pretty weak to steer those big tires. So back to the drawing board. Put in a new gas tank. Took it for a spin yesterday out in the snow. Its pretty impressive. motor ran at about 180 degrees but it was cold out. This thing is fast!!

 

[Nitro Nerd]

The Tower hobbies servo I put in for the throttle is only a 40 oz so its not the greatest but it works for now. So I'm going to buy a high torgue steering servo and move that traxxas to my throttle/brake.
.

The emphasis for throttle servo should be speed. It does not require much torque to pull slide carb and apply brakes. Thus a 80oz and 500oz are virtually the same. With steering, speed is useless with out torque, but a strong, slow steering servo is useless if you want your vehicle to be quick. Hopefully that makes sense. So if that 133oz servo was slower than the 80oz you will not see any improvement...and even if it were the same speed, it would not be very recognizable. The minimum steering is [email protected] for an MT....in my opinion. That is where you'd start to see and feel a difference.

 

[Knightrider955]

The emphasis for throttle servo should be speed. It does not require much torque to pull slide carb and apply brakes. Thus a 80oz and 500oz are virtually the same. With steering, speed is useless with out torque, but a strong, slow steering servo is useless if you want your vehicle to be quick. Hopefully that makes sense. So if that 133oz servo was slower than the 80oz you will not see any improvement...and even if it were the same speed, it would not be very recognizable. The minimum steering is [email protected] for an MT....in my opinion. That is where you'd start to see and feel a difference.

Thanks for the input, unforyunatly I can't sprnd 100 bucks on a servo. Do you know of any quality servos for a buget?

 

[Nitrotrout]

The emphasis for throttle servo should be speed. It does not require much torque to pull slide carb and apply brakes. Thus a 80oz and 500oz are virtually the same. With steering, speed is useless with out torque, but a strong, slow steering servo is useless if you want your vehicle to be quick. Hopefully that makes sense. So if that 133oz servo was slower than the 80oz you will not see any improvement...and even if it were the same speed, it would not be very recognizable. The minimum steering is [email protected] for an MT....in my opinion. That is where you'd start to see and feel a difference.

LOL! Nerd, for a "new to RC" feller, you're quite knowledgeable when it comes to servos and what not.


@knightrider, try out this servo data base and find which servo best fits your demands.
Dimensions, torque, speed, and cost are all listed. I prefer Hitec, Savox, and Futaba
but there's many other brands that are just as good if not better.
There's also many servos that are cheaper, but as far as servos go, you get what you pay for IMO.

http://www.servodatabase.com/

 

[1mtx1]

View attachment 13442

The Big Dog!! Next to my old ST-15.

that was my first nitro that st-15 was junk