boost problem ie its all gone

[Nik da Greek]

Yeah, sounds like what mine was doing. Don\'t quite understand the exact mechanics of it all, but if the primary\'s jamming, it\'ll never change over properly to the secondary cos it isn\'t building the correct pressure to switch. It was explained to me something like that, only a lot more complicated, and that\'s my rather short and hazy-memoried version of it :confused:. Dunno how different that\'d be for a non-sequential set-up, though.

....not being much help really, sorry :Hammer

[cyman]

Yeah, sounds like what mine was doing. Don\'t quite understand the exact mechanics of it all, but if the primary\'s jamming, it\'ll never change over properly to the secondary cos it isn\'t building the correct pressure to switch. It was explained to me something like that, only a lot more complicated, and that\'s my rather short and hazy-memoried version of it :confused:. Dunno how different that\'d be for a non-sequential set-up, though.
 
....not being much help really, sorry :Hammer

thing is mine desnt have all that gubbins on to change to the 2nd as its non sequential.

[Nik da Greek]

Yeah, that\'s why I dont think I\'m being too much help....

[cyman]

Yeah, that\'s why I dont think I\'m being too much help....

hehe np mate some feedback and ideas is def better than none.
 
 
ive just spoken to turbo technics who supplied the turbos gone through everything and his response is either cracked or broken wastegate stopping the turbos spooling up at all or at least not enought to do anything.
 
so unless anyone else comes up with any ideas i will be taking the turbos off to check it all out. and i really dont want to do that in this weather

[cyman]

although i have posted some bits of what ive done i thought i would post it in a bit more detail to see if anyone else has any ideas before i take the tubs off. this is what ive found

front turbo is fine very little endfloat (they were new from turbo technics around 5-10k ago) and spins freely. however on idle and below 2k revs it hardly moves and actually stops most of the time. when you rev it hard it does spin up but not what i would call quickly.

the wastegate actuator works fine and the actuator rod moves and so does the arm on the wastegate. however we activated the actuator at around 4k revs and it made little or no diference to the speed of the front turbo.

used an inspection camera down the rear turbo inlet to check the movement but on idle and when we reved the car there was no movement.

removed all flexis between turbo and throttle body none are split all were tight.

visually checked the ic which is a trust alluminium smic and could see no splits.

visually checked the vaccum pipes could find no splits all the controls and valves for the sequential setup have all been blanked and removed as this is non seq so not much to go wrong.

anyone got any ideas bearing in mind that i have zero boost not just low boost none at all.

cheers

si

[jackaleks]

i\'m no turbo expert, but might it be something to do with the turbine and not the compressor? maybe if a few of the vanes on the turbine have bent/broken and the exhaust gasses aren\'t flowing over them properly, it would stop the compressor from spinning, or even if something is lodged in the shaft or centre housing?
 
not sure if this would have an effect on both turbos, and i guess the only way to find out would be to pull them anyway!

[cyman]

update:
 
i managed to strip enough of the pipework etc ready to take the tubs off to check the rear tub to see if it spins. the simple answer is no well it didnt but after a bit of wiggleing it does now but it jams and rattles/jangles from the exhaust side. there doesnt seem to be to much endfloat on the air side and i have managed to get my fingers into the manifold to check the vains on the exhaust side they all seem to be intacked but it does move then seem to jam.
 
what i find strange about this and please correct me if i\'m wrong but the most probable cause is bearing failure (i am hoping that nothing has come from engine side and is jamming it up) however normally if a bearing fails doesnt the oil seal go and send oil down the inlet side?? this is what i have seen on other cars! maybe someone else has had this kind of failure before?? unless maybe the oil feed pipe is blocked that caused it to fail hense no oil anywhere!!
 
hopefully will get it stripped down tommorrow and will be able to get to the bottom of it.

[ro284]

Hows it going Si, any updates?
Bob

[rx jamie]

yeah it sounds like a bearing failure. turbos dont always smoke when bust.

[cyman]

sorry for its been a while been a bit busy on the car heres an update.
 
stripped the turbos off the car found that the previous owner\'s idea of finishing the non seq setup was not very good. the bracket holding the pre spool flap open was moving causing the flap to open and close a little bit this caused it to constantly tap agains a 20mm dowel that had been welded inside the manifold to keep the pre spool flap open (one spot weld is all that held it) speaking to the previous owner he said he had no knowledge that it was there. anyway what happened is the spot weld broke and luckily for me rather than drop in the engine it literally just stopped the 2nd turbo from spinning causing complete loss of boost. you can imagine what was going through my mind when this piece of metal/dowel dropped out of the turbos.
 
i have since stripped everything down and i am glad to say there isnt a mark on the turbo vains no damage whatsoever it literally jammed in place when i stopped and luckily didnt bounce all over the place. i\'m very glad about that as the tubs were brand new from turbo technics and have only covered about 10k.
 
so the things i have done since i have stripped everything down. i had to drill 2 studs out of the manifold which ive done and whilst it was off i got the pre spool inlet welded up and then ported and matched both exhaust outlets to the gasket so they are now the same size and flowed (if anyone has seen the outlet in the manifold is much smaller for the 2nd turbo than the first prob because it took into account the pre spool port aswell) matched the inlets on the turbo pack to the manifold/gasket aswell also took out some of the sharp angles inside the manifold for flow i also removed the pre spool flap and and got both the inlet side and outlet side of that area welded up so no exhaust would flow that way disturbing flow into the 2nd turbo. matched all the housings to gaskets taking out any sharp edges/angles at the same time and did some flowing.
 
also on closer inspection the wastegate was standard (it was supposed to be ported) so i etched the outline of the flap and have taken the opening down to about 1/2 a mm all around instead of the 3 mm that was there and flowed an cut back inside as it was very restrictive inside with 90 degree angles so that has been flowed aswell.
 
all these mods have been taken from details of the rich mans non sequential setup from here http://www.rx7club.com/showthread.php?t=663013&highlight=non+sequential and a few other threads on the site i have not gone quite as far as these pics because frankly i dont have 40 hours free to do it.
 
anyway this is supposed to allow the turbos to spool up quicker moving peak power further down the rev range. whether or not it does is another matter but i thought seeing as i had the turbo pack off i may aswell do things right.
 
sorry for not doing any pics it was the last thing on my mind when i was sorting this out.
 
and if anyone is thinking of doing anything like this get a carbide cutter i got one that fits in a dremel for around a tenner it really goes through the manifold/housings like butter then finis with some grinding stones and the a sanding flapper wheel for final smoothing.
 
i hope this makes sense.

[Bobbit]

Glad you\'re getting it sorted bud. And how lucky was that, time for you to go buy a lotto ticket if your luck is that good at the mo!

[cyman]

update:

ive just got the car back together without any major dramas. once it was run up and all the fluids sorted i took it for a 10 mile run just to see how it was. i have to say i am more than happy the turbos are reaching peak between 500-800rpm sooner which may not sound a lot but makes it pick up that bit quicker. also after all the porting etc the car is much smoother on pick up at lower revs aswell makeng for a nicer drive.

[ro284]

:Thumbsup! Well done Si, good work there, with some good results, sounds as though the mods you did would be good as part of the non seq mod,interesting that the spool up is earlier in the rev range.
Bob