SiNfidelity

Help please!

Does anyone know how different the twin turbos are between a Cosmo 20b and a s8 fd rx7?

The seals have crapped out on the fd twins n it's blowing lotsa smoke on deceleration and at low idle. Burning oil! I have the 20b twins still n was thinking maybe I can just swap em out. Put the 20b turbos onto the fd turbo manifold etc. Anyone here looked at these side by side?

I'm about to buy secondhand fd turbos tomorrow for $200, but they may have the same problem in a month or so, they have 70,000km on them and these ones in the s8 have 77,000km.

The fd is auto n it's the gfs car, she don't want it to go faster, just reliable and not embarrassingly smoking everyone out.

Ps I've been looking for hrs for an answer. Grrrr

Natey

iTrader: (19)

Cosmo turbos are a little smaller.
https://www.rx7club.com/3rd-generati...-twins-987146/

j9fd3s

iTrader: (3)

all of the factory turbos are made by hitachi.

the 13B cosmo uses a pair of HT-10's
the FD uses a pair of HT-12's, and then the 280hp version uses an HT-12 with abraidable seals.

the 20B uses an HT-15 and HT-10

the FC used a single HT-18.

SiNfidelity

So would the footprint for each be too different, to be interchangeable?

Like the 20bs will not fit I the Fd's manifold?

j9fd3s

iTrader: (3)

the manifolds for each engine, 20B-REW, 13B-RE and 13B-REW, and 13B-T are all different.

SiNfidelity

Ok next question.

Has anyone on here ever fitted 20b turbos to fd engine?

The ht15 seems like a nice choice for the twin turbo secondary

SiNfidelity

K. Thanks for the info guys.
I need to find a low kms set of twins then. Damn.
It's just the gfs car so not after big power.
Think she may sell it n keep her rx8 instead. Chuck a baby turbo on it etc

Tom93R1

iTrader: (2)

FD turbos can last so don't worry about 70k km's, turbo life span is all over the place.
When I first got my FD the turbos failed at about 45k miles. I put a set on with 110k miles (never rebuilt) and they lasted me another 50k miles. I replaced them because I thought they were making noise but it ended up being something else, they still looked fine.

SiNfidelity

Will s6-7 turbos easily fit s8? I found some twins with low Kms and no shaft play but guy not sure what series they are.

I have heard there are some minor differences . Maybe I can swap the actual turbos off the manifold and keep s8 manifold waste gates and vac lines etc?

Any help/opinions greatly appreciated as I really need to fix the fd ASAP.. The front turbo has so much play side to side.

j9fd3s

iTrader: (3)

when the 99 Rx7 came out in 1998, they had two engines. the 265ps version, and the 280ps version. the 265ps version has the same turbos that the previous cars had. the 280ps versions have an upgraded turbo set, it is a little more efficient, and they are set to boost a little higher.

they both use the same exhaust manifold and intake pipes and stuff, so either one will fit any FD engine.

the 280ps turbos use a bolt on compressor housing, and the others have a snap ring.

SiNfidelity

Beauty! Thanks for that. We are selling it so I just need it running.

SiNfidelity

Is it too hard to pull the twins off without removing the engine?
I know the 20b cosmo was impossible but maybe the fd is easier??

Tem120

iTrader: (5)

Chucking a turbo into the 8 has been known to cause nothing but head aches and blown motors ( unles you rew swap it )

if you are looking for good condition twins , get in contact with Fritz Flynn I'm sure he has a good set of low millage twins .

Tem120

iTrader: (5)

it isnt as difficult as some people make it seem , its easier if you take a couple of the studs out first take apart the y pipe and intakes and then get inder it remove the down pipe, then work on the bolts that hold the turbo . I had to pull the turbo from the top after I took it off you will have to bend and twist it a bit to fit and pass the AC lines ,


Make sure you drain the oil , and loosen the oil / water feed to teh turbos as well .

WHEN YOU TAKE HTE TURBOS OUT THIS IS VERY IMPORTANT !! CAREFUL NOT TO BEND THE OIL RETURN LINES FOR THE TURBOS ! OTEHR WISE RE ALIGNING THEM WILL BE A PAIN IN THE ***

SiNfidelity

Great advice thanks

I'm lucky it's a 2000 model, so the shield bolts were a breeze and by the looks of the remaining bolts I doubt any will give me problems.

When u say drain oil, from sump or just from turbos?

Tom93R1

iTrader: (2)

Oil drains in from the turbos above the oil pan, as long as you aren't overfilled or have the front jacked up at some crazy angle you shouldn't have to drain the oil. It's not a bad idea to drain it anyway since you have it up in the air and it's probably less messy than finding out you were overfilled while you are removing turbos.

Tem120

iTrader: (5)

I drained it from the sump , well because I didnt want to risk the oil spilling just in case , and my car was lifted quite a bit in the front so just because I was paranoid.

But as tom said , i guess you do not have to drain the oil.

SiNfidelity

Thought I better post that the turbo change was fairly easy. Being a 2000 model meant the bolts weren't totally corroded etc.

Put car as high on ramps as I could n that's about it. Trying to get the turbos back on, complete with gaskets was a little tricky.

I did break the rear top bolt between turbo manifold and exhaust manifold when putting it back together, but at that stage I couldn't be fked ripping it apart again. So far it's holding up, no leaks, but I'm guessing it's a matter of time!! When it goes I'll convert to a single.

Thanks for the advice peeps