badbanshee509 Posted January 20, 2013 Report Posted January 20, 2013 ok so ive been browsing around and since im new to the drag seen and came a cross sreight cut gears, i see many different ratios, what is the purpose of these gears, and how would you know the one that fits your application? Quote
Finch Posted January 20, 2013 Report Posted January 20, 2013 Straight cuts take some of the side load off the crank thay oem helical gears cause. Asphalt racers usually use the smaller ratio so they don't need as big of front sprocket. Sent from my SGH-T999 using Tapatalk 2 Quote
sleeper06 Posted January 20, 2013 Report Posted January 20, 2013 Well put ,I need it for more gear than most so I run 2:36 on pavemennt Quote
badbanshee509 Posted January 21, 2013 Author Report Posted January 21, 2013 so when do you know you need to mess with that gear, like im a 4 mill stock cylinder, when is it time to mess with it? i do asphalt and drag strip racing Quote
Finch Posted January 21, 2013 Report Posted January 21, 2013 some say your dont need them till ya go real big. i got them with my ss motor. If ya can afford them, there not gonna hurt anything having them, and as said do help relieve side load on the crank. Quote
trickedcarbine Posted January 21, 2013 Report Posted January 21, 2013 I'd imagine for asphalt racing the motor size isn't so much the deciding factor. You probably don't NEED them till about 100+HP. However I you run long stretches like quater mile they would benefit you to help give you more gear Quote
sheerider1026 Posted January 21, 2013 Report Posted January 21, 2013 Eliminating any side load on the crank to nearly nothing is always beneficial Quote
badbanshee509 Posted January 21, 2013 Author Report Posted January 21, 2013 so releaving side load, do that free up any H.P.? and if so how much do it free up. Quote
locogato11283 Posted January 21, 2013 Report Posted January 21, 2013 so releaving side load, do that free up any H.P.? and if so how much do it free up. I think I've heard 1-2. Quote
dajogejr Posted January 21, 2013 Report Posted January 21, 2013 On your size motor, OP, not needed to be honest. However, if you're one of those guys that is a firm believer in overkill and insurance (nothing wrong with that...) it sure won't hurt a thing other than your wallet... Quote
badbanshee509 Posted January 21, 2013 Author Report Posted January 21, 2013 lol so i guess ill hold up on buying one untill i go 4 mil DM, but once i get their how would you know which ratio to really select, ive seen many different ratios Quote
dajogejr Posted January 21, 2013 Report Posted January 21, 2013 lol so i guess ill hold up on buying one untill i go 4 mil DM, but once i get their how would you know which ratio to really select, ive seen many different ratios Good question. It boils down to what size front sprocket you need to run for the motor. If you start getting above 17 ...might be a better idea to get a different ratio. I'm fairly certain you can go up to 19 on front with stock cases..but that's paper thin clearance...and that big of sprockets are harder to find AND more expensive. SlowerThanYou or Tedder can probably give good insight on pavement gearing/setup. Quote
badbanshee509 Posted January 21, 2013 Author Report Posted January 21, 2013 so 17 front srproket is the highest the you guys would recomend befor changing the streight cut gears out? and again how whould u determin what ratio to choose once you get to this point, your above comment makes really good since dajogejr........ .... Quote
badbanshee509 Posted January 21, 2013 Author Report Posted January 21, 2013 and lets say i stay with my 18 front sproket (not saying thats what i have) and im running good track numbers, would slaping one of the streight cut gears in give me more top end or bottom end HP, or is the puropse of the gears just to releave case pressure an will not give you any more top or bottom end power? will cause you to go through your gears faster or slower? Quote
dajogejr Posted January 21, 2013 Report Posted January 21, 2013 I'm not going to say it'll give you more power..(other than the 1-2 HP advertised due to less drag while spinning.) I'll say they'll allow you to more effectively use the power you have. With any straight line, A to B racing, the goal is to be at the RPM limit of an engine design at the very, very end of the track. In other words, you should be running out of gear going through the traps. If you run out before...you're leaving ET and MPH on the table. Same thing if you're going past the traps. So, it's up to you on what tire size, air pressure and gear ratios work best for you. It's not about case pressure, it's about gearing and room. A big, big motor will blow through gearing available like nothing. The ability to run a sprocket up front that allows your motor to pull is key. You get a big motor (I'm talking big) even a 17, 18 or 19 won't be enough on stock primaries. Or...I'll go the other way. You've got a 19 up front and 38/39 out back and you still run out of gear at the end of the track before you hit the traps. Change primary ratios...and now you'll be able to put enough gear on it to pull through the traps, instead of stopping short. Hope that all makes sense... I'm not a pavement guy, so numbers, gearing are not my thing. But the idea and principles are the same. Quote
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