tcb100

What do we pick up in the quarter by switching to a 4.33 rear?

Any substantial downsides? The jump from 4.11 to 4.33 does not seem like that big a deal but..?. I know top end will suffer but who runs 160 anyway. Are the RPMS sufficiently higher to make it obnoxious at highway speedsin 5th?

Any and all comments appreciated.

CTHIS RX7

you probably won't notice to much difference.
on the highway at 60MPH the revs sit just on 3000rpm in my car with the 4.3s

AnthonyNYC

iTrader: (3)

It helped me a great deal. The car went from 11.4 to 11.2/11.1 with the change to 4.33s.

My 60ft time went from mid 1.6's to low 1.5's.

I now finished the quarter mile in 4th gear in the peak area of the power band.

I was the only thing I changed to get the car to 11.1/11.2 since at the time I did not want to switch from the stock twins so to get more HP, I was limited on options.

I did not want to use nitrous so I tried the gears and it worked well for me.

Anthony

tcb100

Thanks to both of you.

I have not yet decided to take the plunge to a midpipe (probably this summer) so I am casting about for alternative bumps that will leave the car emissions legal and streetable, but still get me into the 11s. I ought to make it with powershifting, something I was afraid to do last year with a grumpy tranny, but two tenths is a bunch! Looks like a winner.

93redFD

some say it help, some say they couldnt tell a difference. I would go with something like a custom 4.5 or something.

Wargasm

To accurately answer this question, you need to look at the whole car and what you want it to be used for. Your car, not someone else's.

By increasing the ring and pinion ratio, you will get more power to the ground at a given RPM... that is true. But you also have to shift sooner to the next gear where you have a little less force. So that's one thing to think about.

Another thing which I think is overlooked by most people is how much power do you need to put down and how much CAN you put down?

Let's say you're a drag racer... you need to be able to launch and not spin excessively. On the other hand if you're a road racer, you will not be using first at all probably so your important gears are probably 3rd and 4th where you can put down your power a little more easily. The road racer guy may be able to use a 4.77, but Mr. Dragracer might not have the tires (or 5 spare diffs!) to keep a 4.77 launching well.

Another thing is that a stock twins car with 300-325 rwhp might do just fine on one ratio, while a single turbo with 450 rwhp might be completely uncontrollable with that ratio.

Anyhow, I don't have a magic answer for you... I'm just trying to point out that you need to think about the overall car package before making your decision.

My friend used to have a 4.3 on his FD and he said he liked it fine...

My FD with the stock sized tires on it spins 1st, 2nd, and sometimes even third even on a roll. So I don't want to get a 4.3 until I get more tire.

The one kinda neat thing I did do to my car was to change the 5th gear ratio from 0.719 to 0.806. This make 5th gear a really nice gear for cruising on the highway I still can make it to a 180 mph top speed if I want to I have been considering going to a 4.3 myself, but since I can't even keep the rear planted now, I want to get that under control first.

Brian

cartervs

Info on Scudra site re 4:30's Carter

twint78

wargasm good point.i plan on going with a 4.77 with around 500hp.when my resurrection is done.would this be sick?

Wargasm

The main issue with a 4.77 rear is that your first gear is now going to be about 16:1 ratio which is pretty high if you want to drag race. If you have 500 rwhp, you're going to need very large tires and strong diff/axles/driveshaft/transmission to launch it hard at the drag strip. For cruising around town, it would be fine of course. I'm not saying you can't do it, I'm just saying you're going to need a solid driveline to actually USE it all in first gear.

Your other option is to forget all about 1st gear and just start with 2nd gear. The problem here is that your "new" 2nd overall ratio will be about 33% less force at the wheels than the stock 1st ratio. So you need extra power to make it move. 500 rwhp might be true up at peak, but getting off the line, it will have pretty much the same power as a bone stock RX-7 from 0-2500 RPM.

I've often wondered if any drag racer types with very powerful cars have tried launching in 2nd?

Anyhow don't listen TOO much to my advice when it comes to dragging since I never do it anyhow! I am pretty sure that with a drivetrain that can hook up the power, you're going to get a good time with a higher rear end.

Brian

machinehead

I have been wanting to do it for a long time. Mainly for the reason stated above by AnthonyNYC , in the 1/4 mile, with slicks I am at the top of 3rd and just shifting into 4th at the last stretch of the track which is a killer. What do I do? I shift earlier into 4th than I'd like. Not a great solution, but cheaper than gears. When I do the gears I will also do the diff so there's a 1,000.00 that I am not looking forward to spending...

88fc3sw/HX83

I was doing 2nd gear launches and completely busted my tranny and also had a broken stationary gear. Rob from Pineapple told me to NEVER do that again, but I doint understand what could be so bad about it. Anyone have any comments about this?