Gears ratios with C4

[rednine4]

I know there are calculations to do that tell what rpm my engine will be at but i am more interested in opinions/experiences here.


Here's what I have.. 302 swapped in a BII with 3:73 gears and stock (28" tires) with a c4/c5 transmission.

My concern is not so much with highway driving but around where I live the speed limits are 45-55mph . at 45mph it is OK but I typically drive 5mph over the speed limit so at 55-60mph it is screaming a bit much for my liking. Do you think if I had 31" tires I would be gaining enough to bring it back into the "OK" rpm range (I dont have a tach). Or should I just invest in some gears?

I really like the 3:73 ratio for offroad, but I hate to have the engine all wound up at only 55mph

 

[85_Ranger4x4]

I went from 235's to 31's and I only lost like 100-200 RPM @ 55mph.

It is still high (about 2600ish) but unless you get an ungodly steep gear like they did back in the day or really big tires (your trans won't like either) you are kind of stuck with it unless you go with an overdrive transmission.

My Ranger is pretty much a screw around toy so I don't really care, for highway travel my F-150 that idles down the road at 1400RPM with OD gets a lot better milage.

 

[rednine4]

I kinda figured that was the truth lol... I was hoping you would chime in too since your truck has a very similar setup... anyhow yeah I think i'm just gonna slap 31's on it and deal with it.... after all i built it to be a fun toy so i may as well keep it mostly offroad

 

[Maverick]

Are you more worried about noise, or possibly hurting something? You are far from "screaming" your engine at 60mph with the combo you currently have. I daily drove my 72 Maverick with 3.55 gears and 24" tires. At 65mph it was turning around 3400rpm, which is about 600rpm more than you're turning at 60mph. Other than the noise and crappy mileage, it was a non issue for years. You could drop to 3.45 gears, which came in tons of BII's and you could probably score a set for next to nothing (I've thrown a few sets away). Or you could do upgrade to 31's, either will net you a drop of about 200rpm. If you already want bigger tires, it makes a great excuse. I sure wouldn't go through the hassle of re-gearing for 200rpm, but then again there is no real reason to do either at the rpm youre currently running at.

 

[rednine4]

Very good point. For me it's both noise and gas mileage.. I didnt swap the v8 for good gas mileage but at 3+ bucks a gallon i try to conserve gas when im not out flooring it lol. I will try the tires and probably be fine..