washbum17

i have a s4 tt with a street port with 10,000 hard miles on it that was running 15 psi on stock fuel system(bought it that way) put stock turbo on and was still running 12 psi and lean. got on highway and didnt get on it maybe half throttle and heard grinding sound then loss of power...... compression tested it got 3 hits above 90 on front rotar and one hit of around 10 on rear. did i lose apex seal, side seal, or what...... pls help

RXnos1200

iTrader: (24)

sounds like the apex seal if you only got 1 hit of compression.....

washbum17

dont tell me that, thats the last thing i need lol. is it normal when u lose apex seal for the turbo to make peak boost in neutral........ and if front roter is is strong can i just rebuild the rear or should i just do both

EnjoiPugs

You will want to do it the right way and do both. You'll understand once you read the procedure. It sounds like apex seal to me as well. If you think about the rotor, it has three sides so if one of the apex seals goes out you will lose the compression on two sides of the rotor, but the third side still has both it's apex seals. That's why I say apex seal.

K-Tune

iTrader: (26)

Sounds blown to me, you'll probably need to source a rotor housing and rotor...

RotaryEvolution

iTrader: (30)

obviously if its not generating compression you can add 2 and 2 together.

K-Tune

iTrader: (26)

in the future, any time you operate an engine outside of its stock parameters a wideband display should be fitted, otherwise you have no idea how unsafe an engine is.

washbum17

ya i have a wide band on it and if i did get on it as soon as it would go lean ( around 5000rpm ) id let off or shift but the guy who had it before me dogged it so who knows how long he would run it lean. i knew a lot about a rotary just never been around a blown one till now but thanx for the input. guess ima have to just tear it down and find out how bad it killed housing. im contemplating on either to get this one rebuilt for two grand cuz its street ported already or just get one of the ones they sell on ebay, drop it in and call it a day lol

Jimmy2222

iTrader: (3)

Blown seal. Upgrade fuel system and re-build properly. 15 and 12 psi is insane for stock fuel system.

SpeedOfLife

iTrader: (16)

You heard it grind. I'm willing to bet money at least one of your housings is completely trashed. You'd best check your turbo when you get in there, too, because you might have damaged your turbine. It's also possible the whole cause of this was your impeller blowing apart, but since you got compression on one rotor and not the other I have serious doubts about that and it's uncommon to boot.

For future reference, the wideband is better used when you use it to tune. Watching it read lean as your indicator to let off the throttle is NOT very useful. Case in point.

washbum17

ya....i knew it wasnt right way but u know how things are now adays moneys tight lol but on other hand would have been much cheaper to upgrade then to rebuid. but i only put about 200 miles on before it went. guy who had it before me was running a 60-1 on it at 15 psi then i went back to stock turbo and was hoping to run stock boost but as we all know stock waste gate sucks, add a street port and it still ran 12. he also had computer flashed to run peak fuel output as soon as u were on gas...... shitty set up all the way around but i got car cuz its a 88 convertable with tt drive tran with all s5 exterior and interior cars in great shape..... but thanx for all the input guys. and anyone have info on super seals

washbum17

bump