I need to find out all about gearing. thats the next thing on my list to learn, and there isn't a whole lot about it on here as far as I can tell. Does anyone have any links to info about gearing? like what gearing sets do what and how and why? basically any info at all

thanks!

 

There's really not much to learn, it's kind of self-evident....

Each time the engine rotates, it takes in a certain amount of fuel, and releases a corresponding amount of energy. The more times the engine turns in relation to the number of times the wheels turn, the more power the wheels get. Basically it's just like increasing the length of a lever; the side you push on has to move farther, but you can exert more force on the thing you're prying on.

The ideal gear for a car is one that keeps the engine in its optimum RPM range. Too low a number will keep the engine at a low RPM all the time, where it can't produce much power; too high a number may force the engine to have to run at such a high RPM that it is beyond its peak torque RPM, in which case it will slow the car down. TPI cars, with their extremely limited RPM range that is a direct consequence of the anti-performance design of TPI, are particularly sensitive to this, and can easily be over-geared.

Think of what happens when you shift your transmission gears. Now imagine what it would be like to permanently shift them all up or down equally. That's what the rear end gearing does.

 

ok interesting, but is there some sort of comparison chart, or maybe some info stating what gears are better what what particular setup??

I am putting a new engine in within the next 3 months, 375 horses or so, comparable torque, carbed setup. I don't have Posi rear end. What would be good for this thing?

thanks!

 

Put the exact parts you intend to use into some simulator program such as Desktop Dyno; be honest, don't blue-sky a bunch of stuff if you're going to leave it stock; make all your assumptions as pessimistic as possible. Then take a look at where it says your torque peak and HP peak RPM are. Gear the car so that it goes through the traps at about 200 RPM below where DD says its max HP will be. You can use any drag racing calculator to find trap speed based on HP and car weight. Again, with the weight, don't get too optimistic; overly aggressive projections that aren't realistic will produce stupid nimbers that won't work.

 

I see and wheres aboot would I happen to find this desk dyno program?

thanks!

 

Summit etc.

 

Autozone has DD2000.

Overall picking gears is tough! Its depends on how you plan to use your combo. A 1 inch change in rear tire height has a huge effect on final gearing, a consideration more for the 1/4 mile Vs. perfect street gearing. Picking gears and slicks for best ET is a true science and not a crap shoot, hence the reason Mickey Thompson makes 26,27,28,30,31,32 inch Et Streets. Post what you will be running and you should get some replies.

 

Just a nice streetable 350 engine. 350-375 Horsepower and torque to match roughly. New exhaust system. Still have to choose between the engine I want whether that be the LT1 I found for like 1200 or the one that my machinist can build for a bit more. The LT1 will have its stock intake, the Machined one would have a carb.

Nothing crazy, want a nice bit of get up and go, but I really don't speed. I just want the power, and the drivability throughout all gears. I have standard gearing now.

I have the 700r4 tranny, rebuilt with high performance parts, so it can take more of a beating.

cheers!