Man oh man the slowness!

[CENthasizer]

Well, i hooked up my venom speed meter to my CEN ct4-s, with the OS .21 rg-x, now i thought a bigger engine with more hp, and more rpm's would launch this thing better then the stock (.9hp, 28,000max claimed 73mph), i found out today that it could hit 42mph max! That sucks! I know the speed meter has some flaws in accuracy, but it should do inreality 75-80mph right?
Anyways i had a full block to accelerate and brake, i heard the engine rev high, but it could be that the second gear is not engauging (its a clutch style and its hard to hear the shift)
Does anyone have any suggestions on what i could do to get more speed out of this engine, and if it was a good idea to go to the .21 on this car?

Thanks!

[Crashmaxx]

It may be that it isn't hitting second, but it won't go 75-80. That claim from CEN is all BS. I would expect 60 at best, and with that motor, it sounds a little slow, but it could just be geared poorly. Your speed meter could easily be off if not set properly, but not by that much.

[CENthasizer]

but on CEN's website there was the radar and everything, that engine was a good engine so i think it was possible for it to hit 70ish.
Anyways would you have any suggestions on a newer engine that would put out pure speed? Cen said that this gearing was made for TOP SPEED, and the gearing that i could advance to for top acceleration i tried already, anyways any suggestions?

[lalala]

http://www.radiocontrolzone.com/forums/showthread.php?t=159534

Read his review from above link. I think you two using the same speed meter too. A few members on this board alrady achieve 70+mph out of box. I plan to be next. So i would assume you doing something wrong. I would say its either not hitting 2nd or that engine is just not as good as the stock engine or maybe ur tire just sucks. BTW, according to CEN site, CT4s have like 35000RPM so ur got the wrong figures

[CENthasizer]

well acording to the manuel that came in the box it says NX-15, 0.9hp @28,000 rpm. And according to this guys readings he hit around 28,000 (29,557) and not 32,000, or it could just be it had a max 32.000 and he could only hit 29k.
This MAY be their old figures (for my engine), but i dont know... this whole clutch style 2nd gear shift is a little harder to tune than a finger style 2nd speed clutch. I will take it out tomorrow, and for the speed meter, use mm instead of inchs to get a more accurate input and then convert the kph to mph after.
But when i lifted the car and had it free wheeling (i know, i know VERY bad idea for the engine) but i hit 64 at 70%throttle, and i FELT it hit 2nd gear when it got to 50mph. This is however with the wheels free spinning.
Thanks for your thread link, it was helpful and i got in touch with the guy...
thanks!

[nitrohead5300]

You should hear it when it changes into second regardless if it is a claw type 2 speed or clutch type you should hear a change in pitch. The OS motor you have is a good work horse motor but it is down on power you might want to up-grade

[WS7er]

That motor isn't a high reving engine. HP rating are BS, unless there all done by the same exact dyno, with the same exhaust, which I HIGHLY dought. If you want to run really high speeds, you have to get an on-road engine, the OS rg-x is an offroad, which wiill turn alot more rpms.

[CENthasizer]

Oh so i SHOULD hear it change? thats what i thought but tons of people told me its such a subtle change that you wont hear it. So i will lossen the springs of it to where i can hear it change at mid-high rpm's.
Now the OS .21 WAS my UPGRADE... therefore i spent all my money saved up on it. If you were to suggest an engine better than that with a budget of 100-230(MAX!) what would it be?
thanks

OH! regardless of it being an off road engine, would it not still send my car faster than 42mph? (using a CVEC 21 pipe), Or is that reading correct?! I really thought putting in a bigger engine with more rpm's would send it past a smaller engine with less hp and rpm's, this now makes me a noob...need help...fast!:)

[WS7er]

well, what engine size? .21? .12, .15?

[CENthasizer]

for my car? it can handle any engine .12-.28, you tell me what you had in mind for a "better" engine.
thanks alot for your help

[WS7er]

You can get .12 engines to rev high also. Right now. Nitrohouse is having a sale on there JP Modified .12 5 port race engine. The stock one revs to about 44,000 rpm, and the JP modified one has been ported and polished, and has a special coating on the crankshaft pin that is slippier than teflon, and the crank has been drilled out and filler with epoxy which lightens the crank, which increases the acceleration alot. So I think that engine can rev forever. I have seen it run personally, and it seems the RPM keeps going up. Can probably go 46,000+ rpm. Right now it is $299. If you want to get into the hi-end .21 onroad engine, it will cost $350-$1000. Bigger engine make 2-3x the torque of the .12 size engine, which means you can gear it up high, but with the .21 onroads, they rev 43,000+ rpm, with the same 2-3x the torque.

[CENthasizer]

So better to go with a small block for my budget. What do you think would be the speeds of it, if the stock can hit AROUND 70mph?

[CENthasizer]

is this what your talking about?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=34062&item=5918079791&rd=1&ssPageName=WDVW#ebayphotohosting

Would you suggest then, i sell my NTC3 (brand new kit version that i put together, comes with some hopups), with a fantom fr15 engine, and airtronics reciever (no transmitter), and save up for the jp modified turbo? or just shut up and be happy with what i got?
thanks!

[WS7er]

Yes, that is one of the best .12 out there now. Go to www.jpracing.com. They have pics of them. Also take a look at the onroad .21. The other one I was talking about is a www.nitrohouse.com, under the blowout sale. Another website is www.rc-mushroom.com. They sell the new MAX Power .12 modified. They has a 7 port .12 that is supposed to be BALLISTIC!

[CENthasizer]

So....THIS would be better than the jpracing one?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=34063&item=5918494358&rd=1&ssPageName=WD1V
Its a good price but it is also a 5port.
Now between the jp modified one and this one (i want to stick with paypal payable methods, its easier for me) nitrohobbies takes paypal, and on ebay too.
So between these 2, which would be my best bet?
And to do this i need to sell my ntc3, that i told you about, do you think its worth it, i am in a tug of war with myself about this because its a new car, with a nice engine FR15, BUT if this engine your talking about can BOOST my CEN CT4-s into outer space then i think its worth it. but if it adds like a little more power not that much noticable then i might have to pass, you know what i mean?

[WS7er]

Well, I don't think the stock revs that high, because it is a sport engine. .12 is alot easier on the budget. The most expensive .12 is the JP Mod FX 12 05T 5 port. That is a very good buy on e-bay. They usually run $390-$460. The most expensive .21 onroad engine right now is the JP Mod FX 21 R-02 8 port race. They run for about $800-$850. If I was in your position, I would get the JP FX 3 port. I would soup up one car to the limit, then has 2 cars that are intermediate with performance.

[CENthasizer]

well i need to sell to buy, so if i were going to buy a new enigne i would have to sell the ntc3. and possibly the OS .21 (to go towards a starter box). That 5 port max on ebay is a MODIFIED engine, by the same guy as the 7 port, but if you think the JP is for me, then i CAN use nitrohouse because they DO take paypal, which means i would pay $300 for the engine.

[WS7er]

You just replied before me. I would keep an eye out for the JP FX .21 5 port. The JP engines have a special coating on the crankshaft pin that is slippier than teflon, so the enigne will last a very long time. The Massinio Fattini Modified MAX Power 5 port doesn't have the special coating on the crank, which is the dissadvantage.

[CENthasizer]

did you mean fx .21 5 port or .12? sorry i feel like i am being such a hassle with all these questions. IF you mean the nitohouse blowout sale engine, which is the 5 port .12 then i WILL go with that then.
thanks for all your help

[WS7er]

That JP on Nitrohouse is a VERY Good steal. It is one of there flagship engines. The regular price for that engine was $459 at my LHS. It is a real screamer. So you can choose between the two. The JP 5 port at Nitrohouse, or the JP FX on e-bay. They both will rev extreamly high, and both have the special coating on them. One last thing. The one on nitrohouse is one of the old ones JP used to modify, but don't anymore. So parts for that engine are difficult to find, but you can use the same piston/sleave/rod/crank from the new JP FX.12.

[WS7er]

Also, the JP engine that are on the JP website are the entirely new series of engines, the FX series, with the blue engine head. The one you see on nitrohouse is the one JP orderd from Novarossi, and just modified them. They don't do that anymore. JP's new FX series is engine with the blue engine head,built to JP specs, and modded by JP.

[CENthasizer]

yeah on ebay those new fx series go for like $700!! on ebay! so i fear what they are retail. well i will put a slighly ridiculous reserve price for my ntc3, hmm $320? and IF i sell it then i have enough to play around with on the 2 engines.
thanks for all the help and the posts booster! 259 posts! yay!

[WS7er]

The JP .12 on e-bay that you were looking at is also a FX series engine. They also make off-road buggy engines, and as you have seen, the .21 on-road. The .21 FX you saw on e-bay is actually the cheaper of the 3 .21 JP onroad engine. The JP FX21 R-02 has an Aluminum Sleeve, and 8 ports, and it runs for about $850. So it is either a win/win decision. The JP FX 3 port has performance of the JP FX 5 port, but the 3 port has better fuel economy, and the JP on nitrohouse is just about the same as the JP FX 5 port.

[CENthasizer]

nitrohouse it is then, this WILL increase my speed right?:)

[WS7er]

Well, an engine spinning over 45,000 rpm, it WILL increase the speed alot. Also, what scale is the car?

[CENthasizer]

1/10th scale. My NTC3 had the fr15 (42,500 rpm like 1,6hp?) but the new engine will go in my 1/10th CEN CT4-s

[WS7er]

OK. Just wanted to make sure it is a 1/10 scale car. Thats a very good engine. On cen's wesite, they say the max rpm for the stock engine is 35,000, while the JP will rev to 46,000+ rpm. Also, RC Nitro did a dyno test on the stock Novarossi RS12TSG/S S5, and the dyno results are:

Peak torque: 60.1 oz.-in. @22,000 rpm
Peak bhp: 1.54 @ 28,5000 rpm
Max RPM: 44,000
Plug type: Turbo
Carb type: aluminum 3 needle slide carb w/ 5.4mm bore
Bore: 13.8mm
Stroke: 14mm
Sleeve material: brass/crome

The JP Modified has the following differences:

Special coating on crankcase to dispace heat better

Special coating on the crank pin that is slippier than teflon and has a hardness of dimonds

More agressive cutouts on the crank

Crank drilled out in the center and filled with a special epoxy which lightens it so faster acceleration

Port and Polish to the sleeve

Carb bore bored out to 8.5mm

Ceramic bearings for less bearing drag

[nitrohead5300]

That motor isn't a high reving engine. HP rating are BS, unless there all done by the same exact dyno, with the same exhaust, which I HIGHLY dought. If you want to run really high speeds, you have to get an on-road engine, the OS rg-x is an offroad, which wiill turn alot more rpms. Offroad motors tend to turn less rpms than on road.

[nitrohead5300]

Centhasizer, this is a dumb question but did you remember to change you side pullies? When I used the rc car action speed calculator with your engine rpms, final gear ratio you have, you should hit at least 72 mph, so something is wrong your tranny must not be shifting?

[CENthasizer]

ok well we all know i am NOT using the stock CEN engine, i am using the OS .21 RG, I think there is something wrong with the shift point, i just adjusted the point so that it would shift earlier because i DID hear it shift, and it went from a high pitch sound to a low sound but then it held that low sound and did not rev up more. i'm guessing that once it shifted it could not power it to higher rpm's. So when i changed it to a shorter shift point, i may have change it to change TOO quick, to where it changes at around 20mph and then the revs hold at a medium pitch sound (not loud)
So! i am having problems, could be my engine is not tuned right, could be my transmission... its not the meter itself because i did a walk with it and its pace was correct (i judge by my treadmill and the pace on that).

So on my side pullies i am using 17t, on my pullies that go to the diff pullies, i am using 25t. I dont know how many teeth the diff pullies have. but i am using the STOCK set up, which CEN says is the setup for HIGH speed.
I wish one of you guys were around town to help me out or something, my lhs people arnt that good... well they are in their own sense, but they dont know CEN.
Let me know your thoughts.
thanks

Oh and nitrohead, what exactly did you put in for the rpm's and gear teeth?

[CENthasizer]

ok well here it is my gearing! maybe this will help?
Clutch bell gear 15-19t
spur gears:42-38 (first-second)
Side pullies 17t*
pullies from side to wheel pullies (differentials): 25t
differential gear:39T
Belts;
Main belt (from 25t-front 39t diff):417t
Side belt (middle belt)(17t to 17t):171
rear belt (25t-39t):189

*my manuel says 17t, BUT where i buy my rc parts, they have a manuel online for buying parts, and it say stock 16t. Right now i am using 17t, should i use the 16t?
Let me know guys!
thanks!

[CENthasizer]

Ok well i did the calculator, putting in the above results i got like a max of 47mph (which is what i AM getting). I said 32000rmp, its more like 30,000rpm...but just to see i put 32k, with a tire radius of 2.4" tire radius and it comes out 47mph.
But you know me i could have done it wrong, but let me know what you get if you actually try it out!
thanks so much! i should edit my post to add more info instead of having these 3 posts! sorry

[nitrohead5300]

CENthasizer, my calculations were based on the stock side pullies. I put in your engine rpm 30,000 , kit size tires 2.6 and final drive ratio of 3.2 . Looking at your post I see that you are using smaller diameter tires this will reduce your top-end speed.

[raderrustler]

There are two versions of the ct4, one has lower gearing and will run near the 60 mph mark and the newer version has the taller gearing, make sure your car is hitting top speed in second gear also. Mine did what I set out to do