I'm getting close to having work start on the 20B conversion of my 96 FD. I'm looking for a good streetable car that will (to begin with at least) run with stock internals (my motor is a later C-prefix'd 20B from a 94/5 JC).

My questions are:

1) What turbo would you guys recommend? I was looking at a GT35/40 but it's been suggested that this may not really be 'adequate'??

2) What boost will the stock (late) 20B 'happily' (i.e. daily if necessary) run with? I believe the earlier motors are weaker than the later models (different eccentric shaft).

I'm looking for good power (i.e. more than enough to blow away my single turbo 13B mates!) but not at the expense of reasonable streetability and rebuilding every few months - Easy!

Thanks,
Flint
UK

 

I don't know how much power you are looking for, but even with the stock twin turbos, you can get up to 550 rwhp @ 14-15 psi. (streetported engine, EMS, FMIC, etc)

 

As I said, it wont be ported at all until it needs rebuilding. Basic spec will be 20B, single turbo, Apexi FMIC, E11 and W.I. when I finally get hold of the kit I'm after.

 

How about a T88 or GT42 running 15-18psi?

 

From the VERY little info I've seen of the GT42 is, err, rather big. Any ideas what it'd be like on the street?? I dont want a dead under 4.5K rpm car :-(

Any info on the GT42 any where do you know?

Ditto the T88?

Cheers.

 

Your best source for GT42 info would probably be from Magnus. He knows lots about them, has one on his 13B drag RX-7, sells them from his shop too.
http://www.magnusmotorsports.com/

Not sure where to get good T88 info though.

 

the GT42 is big for a street 13b, but not too big for a 20b. You need to decide how much power you want before anyone can even begin to start recommending a single turbo. You may want to stick with the stock twins until you do have a ported motor.

 

the 20b has a lot more low rpm torque than a 2 rotor, so "lag" isnt as noticable

mike

 

I'm set on getting the single done now at the same time as the conversion, all in one hit. Cant be doing with all those hoses and bits of rubbish taking up the engine bay.

The car will be street driven a lot so I dont want some thing that's going to take 1/2 a mile to spool up.

Any ideas what RWHP a GT35/40 might produce and at what boost?? How much more does a T78 (say) pump over a 35/40??

 

Check out my dyno sheet and setup. This might give some idea what you can realistically expect.

https://www.rx7club.com/forum/showth...hreadid=146081

 

Why not get a GT40?

The Gt35/40 and T78 (greddy) where aimed at the 2 rotor seven, what u need is somthing a bit bigger.

I'd do a little research into how much CFM a 20b uses then get a Turbo to suit your aplication, dont just stick one on as its easy to get hold off.

 

Remember the 13b-rew is the later of the two engines and as such has better Staitionry gears,Oil ways (100psi system) etc just like the T2 Rx so be aware before you start running big HP that it needs more than bolt on goodies.

Also you may want to change the Exhaust port Sleeves to the 13b type as the 20b ones dont flow well and so dont react well to the single turbo mod.

 

Good info, thanks.

I was thinking of the GT40 but I'm still waiting to hear from a couple of people here in the UK as if and how much....

Do you know where I may be able to get one from here Grizzly if I was to go that way? Is there any good info on the GT40 any where out there??!

I'm trying to get together some CFM figures together at the moment.....................................

Ta,
Rich
UK