RX7 FD3S 1993 White smoke
 

hi all, so guys I am new to this forum. I got a 1993 mazda rx7. It's engine was rebuilt about 2 years ago the engine was street ported and left with stock turbos. Lately it has been giving an issue when it is revved high on boost a huge white smoke comes from the back of the exhaust. Straight away I thought it was the turbos removed turbos and both of the turbos where fried. The blades were dented and even the big turbo was stuck so I went ahead bought another 2 second hand turbos. I tested these turbos outside by feeding them oil via a siring and applying 2 bar of pressure the turbos leaked..... However when i've taken these turbos to a local turbo rebuilder he claimed that the turbos where in good working order and so I fitted the turbos in the car. However the issue still persisted of the white smoke it smoked less however it still smoked allot.... So I started thinking that it was from the engine however when I tested the engine with no boost and revved it hard there was no smoke at all...... So I started blaming the turbos once again as they are leaking only when there is pressure applied to the propeller shafts. What do you guys think ? is it a turbo problem or an engine problem ?

Not a 3G guy, but the following may help:
https://www.rx7club.com/3rd-generati...0-rpms-689649/
https://www.rx7club.com/3rd-generati...0-rpms-689649/

thanks for the reply however my fd is only smoking at high revs and when on boost only it won't smoke at all in high revs and off boost. :( to add to it the car delivers power one more reason that I don't think it is from the engine, and if it is a side oil seal then I guess that it would still leave the smoke when off boost at same rpm's no ?

Seals are gone on the turbos.
I fried my T04 on the highway then put it on the dyno.
The car ran fine but if if you let off after the run..poof..smoke show.

so it is a turbo issue not engine issue..... I was thinking to switch to single turbo as it is so rare to find a pair of good twins thank you for your help btw :D

Just to make sure...gain some posts or try to post a thread in the 3rd Gen Specific section.
I am leaning towards a bad shaft seal on the turbos that allow the oil to bypass and burn when the turbos come off boost,which is what my turbo did.
I had an engine that had bad oil control rings and it did create smoke but that was when you were accelerating hard.

yea I accelerate and when I release the gas the smoke screen comes :P when off boost I rev and when I release gas no smoke. I am finding it very difficult to have worn out side oil control rings as it was rebuilt recently (about 2 years ago) and yea I am blaming the shaft however this turbo re builder said that the turbos are in good working order...... Which in the first place I didn't approve of as I did test the turbos with a siring applying 2 bar of pressure and they leaked badly........ Once again thank you for your great help and reply :)

You'll get better knowledgeable answers in 3rd Gen Specific,.
Those guys work on them all the time.
I pieced my FC together with info on this Site and frankly it went like Stink..lol..!
Any issues that arose were dealt with through the Forum too.

My answers are what I perceive to be the Problem,BUT you should get the second opinions of those who deal with the FD platform.
My build was an FC...not that much different but none the less it was as far as I ventured.