ads8525

My Feedback: (34)

I have an Ofna Comp lx with the original .28 engine. My question is how can I get some more speed on the top end. Someone told me I could change the gearing but I'm not sure what gearing they are referring to since it could be at several different points. Any suggestions?

jmaxey51

more teeth on the clutch bell, i think it comes with a 13 tooth clutch bell so you can get a 15 tooth clutch bell but it will take away from the bottom. also you can get an top end pipe for example the Dynamite 086 pipe will work great. very durable and gives it a good bit more top end.

hope this helps a little.

ads8525

My Feedback: (34)

Does Ofna make a 15 tooth clutch bell or are most of them universal so I can buy any manufacturer?

rpg711

Easiest way? Get a taller clutch bell.
Best way? Get a nice engine with a lot of ports... like the Go tech 28R 6+2 port.
It happens to be on sale at A main:
http://www.amainhobbies.com/product_...-Standard-Plug

Specs here:
http://www.go-engine.com/in-products...86P-P420SG.htm

big_poppa49

ads8525, well how it going neighbor. good to see a local on here. I live in Kings Mtn. not very far from Charlotte. Any good tracks your way?

tommygun32

On Special for 8.25

http://www.amainhobbies.com/product_...gen-OFNA-Style

ads8525

My Feedback: (34)

Well hello! I hate to say it but no good tracks my way. Was a nice one out towards Metrolina Expo but it was demolished and is going to be built elsewhere. Hobbytown in Monroe is suppose to be building one as well. Hobby Stop in Rock Hill has a nice track. Currently i beat around on a private track just on the other side of Monroe? Where do you drive at? Any good tracks up your way?

ads8525

My Feedback: (34)

Thanks..How much more speed do you estimate a 15 tooth will add to my top-end?

tommygun32

I'm not sure how much more speed you'll get up top honestly. If memory serves me correctly, I think I tried to put a 16 tooth cb against the stock spur gear (48 tooth I think). That was too much of a jump and the teeth wouldn't mesh. I would have had to change the spur gear. Didn't bother.

It probably wont be that much of a jump. And as was mentioned previously, your bottom end will end up suffering a bit. It all depends on the size of the track you're running and what you're looking for. If you can, try and go head to head with your buddies who are running different cb's and do a comparison.

It also depends on the performance of your engine (which I have no experience with), pipe, clutch, diff oils, etc....they all work in conjunction with eachother

Good luck.

jmaxey51

just know when changing the teeth is will effect the bottom alot. even going from a 13t to an 14t CB will make the bottom alot less snappy.

big_poppa49

Yes, as a matter of fact there is a very nice track in Cherryville, only about 25 min from my house. They have races every sunday and occasionally have a big race, about 4 big races a year. I have heard of the track at hobby stop. I believe the place you were talking about may be the indoor track at Carolinas RC, I think they are re-locating to a better location.

yakfish

My Feedback: (27)

put a gps on the back of the car and see what your real top end is now with the 13T CB and then compare with a 15T CB. I did this with my hyper 7 and with the stock 13T bell and the stock .21 engine the top end was about 35MPH with a 15T CB it was a 40MPH so 2 teeth on the CB should give you about 5 MPH over what you have now.

Argess

Assuming the engine can attain the same rpm with the higher tooth bell, increase in road speed is the ratio of the new to old CBs. For example, going to a 15 from a 13 gives you an increase of 15.38%. So if you were doing 40 mph, you will now do 46.15 mph. As the engine will be more loaded at this higher speed, you may not quite achieve 46 mph, however the ballooning effect from the tires may compensate somewhat. As above, getting 45 mph from the change seems likely.

You will also lose low-end torque, so going up to a 15 might be good for tracks with long straight sections, however for short straights with lots of corners, you would probably be faster around the course by sticking with the 13 tooth CB.

I think most CBs are interchangeable between brands as long as they are all for a big block crankshaft. Most big blocks seem to take the 5x10x4 bearings, so you might be able to tell that way.

supertib

Buy a faster engine ! gearing up is not the answer...you need an engine with a better top end !

tommygun32

True that....and supertib is the man that can make that happen... I have one of his Jammin JPX21 engines and it absolutely RIPS!!

lez1troubles

yep, RPM's is what you want.(and a larger clutch bell with a 46 tooth spur-gear.)