single turbo 13b cosmo?

[mazda speeder]

so i can see it will be about as hard as converting an rx7, but will the auto box cope? what ecu options? thanks

 

[mazda speeder]

need some help, so my exhaust manifold and turbos on my cosmo are dead. there are loads of rx7 twin turbo with manifolds about. i know the twin turbo setup from an rx7 will physically bolt to the engine but would the engine run and would i have to retune the ecu? thannks

 

[rodneooo]

have u trial fitted a set of the fd turbos?

i was always told the studs where the manifold bolts to were in a diff position.
never had an fd block so i have no personal experience.
either way thats the very least of your worries.

youve seen the rats nest of vacuum hoses and solenoids under the intake maniflold. In the fd there is even more. Personally I wouldnt mess it. its just asking for trouble.
You would want to have a very acurate idea of how both systems work, and the purpose or function of every actuator and solenoid on BOTH (cosmo + fd) systems.
You will most likely have to adapt both systems together and fab or modify alot of parts.

the fd system supposedly flows better and safe for about 14psi.
cosmo gets dangerous over 12psi.

 

[mazda speeder]

im sure the block-manifold bolts are ok, because an rx7 manifold gasket fits. But good point about the darn solenoids.

 

[mazda speeder]

so i had a good look today and there are restrictors fitted to the exhaust ports on my 13b, anyone had any experience with removing these? i

 

[Austerror]

Interesting, I don't know if the restrictors are stock.

As for a single turbo, it should work with the stock ECU. Provided the single new turbo does not exceed the standard operating parameters. For example if the stock ECU is only capable of dealing with 15psi, then you will want to ensure that the new turbo won't exceed 15psi. (I don't know what the stock ECU is capable of dealing with)

The ECU should adapt to the different power curve. That is what computers are good for. I doubt that the engine ECU can't deal with just one turbo. Most of the time the engine runs on just one turbo anyway.

 

[13bcosmo]

do you mean the exhaust port sleeves.

Mazdas turbocharged engines do not require exhaust splitters because the turbocharger is very effective in reducing exhaust noise, but these engines are equipped with a steel sleeve in the exhaust port to reduce heat transfer from the exhaust gas to the rotor housing water jacket. In our experience there is no significant horsepower benefit gained from removing the sleeve in either street or race applications. Furthermore, retaining the sleeve allows a better match between the rotor housing and the exhaust manifold.

http://www.racingbeat.com/Tech/Tech.Exhaust.1.htm

I had my sleeves changed to a different type. alloy i believe. supposed to provide better flow.
do your have a defuser that looks like a right angle bracket inside the sleeve?


I was told the cosmo' turbo's are larger than fd's.

can much be done to upgrade the stock turbo's for more boost and to be more efficient? just and idea i had.
kind of want to keep dual hitachi as nearly everyone runs Garrett or hks.
If i was to change it the car would be upto it's 7th.. turbo at 120k's.

wouldn't it risk leaning out simply changing the turbo. I didn't think the ecu self adapted? or could be reflashed?

 

[mazda speeder]

ill take some pictures later, but yeh there are two restrictors in the exhaust ports, apparently to give the cosmo more low down torque, but i think its just to restrict the engine peak power..

 

[13bcosmo]

I think i know what your talking about. sorry to say but it sounds like you have a n/a fc block.

where did you buy the cosmo from? did you drive it at all?
honestly you can't tell this things til you pull the engine apart.

I'm no expert just making assumptions. kind of explains the manifold damage.


hows the engine are the housing re usable what exactly has happened to it?

 

[mazda speeder]

na its definately not an fc block its the original engine mated to chassis, iv read that the cosmo 13b had exhaust port restrictors originally fitted by mazda to boost the low and mid range torque and possibly to improve reliability. with these removed the exhaust ports will be the same as the rx7 13b. however the inlet ports on the cosmo 13b are significantly larger than the rx7s.

 

[mazda speeder]

my engines sweet, the turbos are past it and the exhaust manifold has a crack. im trying to find a replacement. But if i cant i may go down the single turbo conversion route...

 

[rodneooo]

they are the exhaust port sleeves.
Cosmo ones are smaller as they help with gas velocity and stronger pulses to spool better.

if your keeping twin turbos leave them alone...
i dont think u can take them out without having the motor apart anyways.
many people change either take them out of replace with s4 or s5 rx7 ones.

 

[13bcosmo]

I never saw mine prior just an after shot.
I have a straight through sleeve.
can't speak about power gains but it sure did sound different after having it done. slightly louder and there was a more distinct 2 beats.
no longer have a steady idle.


single turbo and manifold is the way to awesome power.

 

[mazda speeder]

ok guys so iv just finished putting me 13b-re engine back together and back into my car, thanks rodneoo for the turbos! I also managed to do the non-sequencial mod! The car pulls strong now after a little bit of lag but the engine feels so much better and sounds sweet!!! will get some pics up soon after a good polish#!

 

[frank20bcosmo]

Look forward to the pics, it will be nice to see.
We will have to get together some time next year at a meet so we can catch up

Frank

 

[rodneooo]

No worries, glad its back together.