12abridgeport

Almost done breaking in my new BP so i'm trying to decide if i want to go with NOS or just to put a low ratio gears. I used to have nitrous before and i know it is a lot of hussle to use it on the street . Has anyone here put a 4.44 or a 4.88 gears in their cars? If so did it make a big difference, if compared to nitrous how many shot that would be? Any responses are appreciated. Thanks

thorin

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12abridgeport

what in the world is this supposed to mean?

BRealistic

NOS may be good for stoplight drags, but it won't make you faster on a tight twisty two lane.

thorin

NO2 also wont make your first gear useless for everyday driving. but then I dont know how you plan to use your car.

12abridgeport

i'm planning on using the car for drag racing and occasional street use. It already eats like 10 mpg so if i put some high gears it's going to eat even more gas so i'm thinking those gears better be doing something, cause nos is only there when you need it plus i think i would probably get more power with it too. What do you guys think?

Keaponlaffen

Nitrous = premature rotary engine death, much like smoking in humans

I would suggest if you're looking for the most power, do all the basics if you haven't yet:

Exhaust
Carburation
Lightening
Gears

Nitrous Oxide will most likely take miles off the life of your engine, so I wouldn't suggest it...

1st7heaven

back in the early 90s when I had a street car, I ran both 4.44 and 4.88s. The 4.88s were cool for occasional street use but your rpms are so high but then again thats what bridgies like I think the 4.44 were perfect, that is what I am using in my autocrosser.

12abridgeport

i wouldn't mind getting some 4.44 probably but i think for the money i'm better off getting a nitrous kit and pushing like a 150-200 shot. Making the car go like 11s in 1/4 mile and eating up on some American muscule.

jeremy

iTrader: (1)

what he was trying to say is summed up as.......

12abridgeport

that's actually pretty funny.......looks pretty real too

REVHED

4.8's would be great for a bridgeport! If you do a lot of highway driveway then 4.44's are a good compromise.

Hans

I got the 4.77s, but car wont start. =/

supposed to drop the speed at 3k in 5th from 62ish to 52ish

Pele

iTrader: (28)

Check out the differential threads around. Miata has 4.3 rear end.

What else ya got besides the Bridgey?

12abridgeport

My modifications to the car are as follow:

12a BP, Holley 600, RB intake, RB exhaust, msd coils, 10mm wires, Holley Blue electric fuel pump, fuel pressure regulator, 4 pack clutch, ACT pressure plate, and transmission shield.

I think it is true, the miata rear end might fit to a 1st gen, i should check that out.

Yeah, Hans let me know how the gears turn out after you start the car.

buzz

I've had 4.44's in two rx's now, a 12a extend and a 13b then 13b bridge - love 'em. 4.8's would be close to ideal for drags but it depends a lot on how much rpm vs speed you want when crossing the line. 4.4 are nice on the street and not running tooo many rpm for highway / open road cruising.
For circuit work its matter of suck it and see - a local track has rotor guys wanting 4.6's for a normal(ish) sized rear tire profile.

MIKE-P-28

iTrader: (1)

Man all I know is the stock 3.909, makes my first gear useless. Its like gas boom red line, or maybe thats cause its turbo charged? LOL Anyways, I have to shift mad quick yo

metalliman

I know this doesn't make a whole lot of sense, but according to my "How to Modify your Mazda RX-7" they say with a bridgeport you can actually increase your gas mileage around the city by going with lower gears. It has something to do with the gears compensating for the poor low end torque. Sounds like the way to go, I don't think I've heard of one person on this forum that wasn't happy with their gear change.

DriveFast7

iTrader: (1)

I'd put at least 4.444 in a bridgeport seeing it's powerband is 7500-9500rpms. You need to get up those rpms quickly and shorter gears are the way to do it.

I put 4.444's in my 12a streetport track only car and it really did speed up the car. If your 12a bp is primarily drag race and occasional street stuff then by all means install the 4.875's. Yes your rpms will increase in the same gear compared to stocker 3.90's but remember the bridgports buck and kick under 4000rpms anyways.

Gatorgunner

do a search on miata diffs. They will fit in older rex's, actually i think i might have the web sites address that explains it.


Yep here it is:
http://members.aol.com/solomiata/Drivetrain.html

smile444

don't the 83gsl's come with 4.44?

FD Racer

I wish they did. I'm putting in 4.44's in soon. 83s come with 3.91s or something.

Rx7carl

Top speed with 4.88's is kinda low. 137 @8500rpms, and first gear is useless except in the pits. Im gonna try a 4.44 in my racer to get it better.

Rx7carl

Man thats funny

12abridgeport

Thanks everyone for their responses, i sure didn't hear no one complain about their low gears. I'm going to try to look into those miata rear ends just so that i could try to save some money.