More power for 12A

[A R]

I was recommended the following by a friend over the water:
 
overlap-port
 
New intake manifold and holley 650
 
488 rear end
 
I am a bit lost on the 488 rear end bit and wonder if it is even possible here in the UK.
 
Any recommendations? I need to start pricing bits and work.
 
I will still need to add the headers too.
 
Cheers,
 
AR

[jon newman]

4.88 to 1 ratio is the diff , only good if racing and using a highly strung bridge port on short straignted circuits.
 get some books or google around using the terms mazda rotary

street port
bridge port
peripheral port

if using on the road get a 13b 6 port and a good 2 1/2 inch exhaust with a holly should be nice.

[Christopher]

Porting and a carb is a good idea. But porting will need a rebuild. Depending on the size of port. I would say 180bhp with a large street port and carb with an exhaust and manifold.

Or direct port nos kit (brand new) I just happen to be selling for a 12a. Just tap two Injector in to your inlet manifold then depending which jets you use the kit can deliver up to 150 bhp. But I would not recommend 150 shot of gas though

Pete.

[A R]

4.88 to 1 ratio is the diff , only good if racing and using a highly strung bridge port.

Basically that is what I want a straight speed car as in a drag type thing but with the odd street outing. I know the 4.88 is the diff, but I did not know that it fitted into ours, or is it a whole new unit?
 
I know it will need a rebuilt, just looking for opinions if it is really worth it or if I should just get a TII adapt it, get some EMS and be done with it. The thing is I am not a fan of Hairdryers LOL.
 
Cheers,
 
AR

[Brett]

Stick with the 12A and give it a damn good porting :Giggle

[shaunwil]

Depends on how many miles is in the engine. The 12A wears out more than breaks and if split sometimes there is nothing salvagable !

Go for a 13b and carb and your laughing !

Shaun

[mpk490p]

if you are sticking with a 12a i will have a weber 45DCOE for sale soon, i also have a 48IDA brand new which \'could\' be up for sale too

[kiwi-jay]

Hiya,

if you still have the webber carb & manifold for a 12a I may be interested.
I\'ve just joined this site.
My normal e-mail is: kiwij4@hotmail.com
Best Wishes - Jeremy.

[bumpstart]

4.88 is a bit too wild for street revs and mild engine
4.44 is on the button for a healthy shift in usable torque,, without a massive drop in top end speed

these " short nose " medium diffs are found in the ford econovan / mazda E series vans from before 1987

-- note that they often come as 26 spline
( from those with floating axles and 6 stud and dual wheels )

 note also that  s1,2 rx7 is 24 spline, and s3 rx7 26, ( a different 26 )

and you will have to transfer the new crown gear onto your guts,,
and fit it against the matching pinion in the head ,
 and dial it in for backlash

NB,, some light duty vans ( those with 4 stud rear ) can come with a geniune 41/10,,, 4.1
( 4.11 is 37/9 ,, long nose found in rx3 )

and these van 4.1\'s are 24 spline, direct fit for 24 spline rx2- 7
( excluding rx4 13b )


PS
KIA can be used as a source to get some of these diffs NEW

[mpk490p]

4.88 is a bit too wild for street revs and mild engine
4.44 is on the button for a healthy shift in usable torque,, without a massive drop in top end speed

these " short nose " medium diffs are found in the ford econovan / mazda E series vans from before 1987

-- note that they often come as 26 spline
( from those with floating axles and 6 stud and dual wheels )

 note also that  s1,2 rx7 is 24 spline, and s3 rx7 26, ( a different 26 )

and you will have to transfer the new crown gear onto your guts,,
and fit it against the matching pinion in the head ,
 and dial it in for backlash

NB,, some light duty vans ( those with 4 stud rear ) can come with a geniune 41/10,,, 4.1
( 4.11 is 37/9 ,, long nose found in rx3 )

and these van 4.1\'s are 24 spline, direct fit for 24 spline rx2- 7
( excluding rx4 13b )


PS
KIA can be used as a source to get some of these diffs NEW

good info thanks :Thumbsup!