I was pondering either getting a bigger rear end gear or gearing the car down to a 430 with smaller diamiter tires. My lab tech told me that sometimes you can over gear engines that produce a really solid torque curve, would there be any danger to my engine simply caused by gearing it down, givin that I still shift like I do now?

 

What do you want to do with the car?
Drag, Auto-X, Road Race, Street?

What other mods do you have?

 

I think the stock gearing is already kinda short, 5th gear at 7k is about 130(I tested it )

 

That doesn't seem right at all. Do you have small tires?

 

No, they should be really close to stock. Stock is 185-70-13, and I have 195-50-15. When I sit the stock wheels/tires next to my 15's the look the same.

Also, 4k in 5th is 80.

 

on my car 7k in 5th gear is aroudn 140

 

dude thats not right at all, my 4th red lines at 7 grand at exactly 100, if you do the math 5th gear will red at 141.2 or somethin like that, but I run out of power at like 125 or so, so I want to gear it up a lil so I can accelerate a lil better, Its a stock 6 port motor, thats why I wanna help it out a little bit.

 

If you look at the car in this thread:
https://www.rx7club.com//showthread....35#post2546335
It's got tiny little tires (you can kinda tell in the first pic)

I can't remember the exact size, but the OD of the tire ends up being a couple inches smaller than stock. The gearing is awesome like this. The power band is better, and the car is definitely quicker, not to mention that this wheel / tire combo is a lot lighter than stock (less rubber and less air).

If I remember, I'll get the exact tire size and calculate some speeds at redline when I get home from work, but as long as you're having fun more than you are cruising on the highway, it can't be that bad.

As far as added wear on the engine, it should be fine.

 

85 gsl-se has a taller 5th gear

 

Sorry bud but the air doesnt weight anyhting.

 

sure it dose, ti has an extra 32 lbs in it

 

i dont think so, i had my car at 137 mph and i still had 1k rpm more to go before redlining so the SE tranny can go about 150-155

 

84 and 85 are a little different

 

dont for get about rhe speedo drive gears, thare are severall different one through out the 1st gens.....

 

4.444 is the generally agreed upon ring and pinion ratio for the performance street driver.

i have those gears in the blue 7 below and it really helped my acceleration. as for top end........... I was doing 125 at the end of the straightaway @ willow springs raceway.... just driver schools, not racing.....it was my daily driver then.....a guy came up to me and said "have you ever seen what happens to a car when it flips at that speed? a 240zx with a roll cage flipped and rolled at that same spot not to long ago. The roof was torn out and wrapped around his roll cage."

He would not have walked away if he didn't have a roll cage. A few weeks after that I had a 10 point roll cage installed. Nuff said.

 

my goal wasnt for top speed, Im rarely over 90 and thats very seldom, but my car needs help 0-60 and I figured sense I have a new set of rims for summer I might as well see if I can help accel by puttin on some low pro tires, I could care less about the odom or speedo lol pshhh who needs those!

 

those will make the gears longer

 

205/60/13 on 13x7 will give shorter gearing and better acceleration. nothing earth shattering but also nice light and inexpensive package

 

Is that what you have on your blue car?