Hey guys iam new to the forum, ive been reading it for awhile though, anyways
I've searched about this topic i just want to get some opinions from you rotarty experts,
by the way the mods to my car are, intake,downpipe, high flow cat,apexi power fc, greddy evo catback, greddy profec b, and poor mans non sequential.
about 2days ago i was just cruising in the 7 not reallly boosting since iam running on the powerfc basemap with the boost set at .50bar, i got on the gas once in second merging on the expressway, my injector duty was at 56percent, and i reached .46bar, air temp at 91C, about 20mins later when i pulled in the driveway i noticed every now and then the idle sound would change to a flub,flub,flub,flub, almost sounding like a streetported motor, but not all the time only everynow and then, also my vaccum dropped from 470-480 to 430-420, i searched and it basiically came up i blew my motor, the only thing is that besides the idle sound and vaccum the car is running perfectly fine, the motor idle's stable at 850-860, it starts up wether the engine is hot or cold, it will boost to whatever i set it at, and it runs smooth, also, before the incident the car used to backfire alot because it ran so rich, but now it rarely backfires, do you guys have any other ideas besides my motor being blown? i know a compression check is the only thing that will really tell, but i wanna see if it maybe anything else before i bring it in to get the compression checked, also before the incident my spark plugs really needed a change, could that have any effect on the engine? thanks in advance guys

 

Dude, your car is fine. 430-420 at idle is better then most healthy engines with mild port. My car vacuum is 390 at 890rpm with full street port.
Your air temp is pretty high thou. becareful not to run high boost with hight air temps. It will cause you to run lean and that means you know what.

 

Yea but my motor is not ported at all? the ports are stock

 

Most of our exhausts sound broken at idle...as if it were a piston engine and missing. But don't worry, your car is fine.

Raj

 

excessive backfiring is usually due to an exhaust leak. Rotaries will pop through the exhaust every so often but if you were getting alot of it definately check for leaks.

How was your air temp 91C? I am in Phoenix and never see anything near that, I will see up to around 70-75 but that is immediately after starting the car when it has been heat soaked.

 

what about the drastic loss of vaccum? i understand how exhaust sounds on the rotary very different, form normal piston engines, but with the change in exhaust sound and vaccum lose i figured i blew the motor, also 185F is regular opperating temp that equals 85C, 95C is only 195F i didn't think that was to high. do you guys think the bad spark plugs had anything to do with it.

 

95C is good for water temps, but not air temp. Water should be anywhere from 85-100c but air should never be anywhere near that hot.

As for the vaccuum loss possibly you managed to get a leak in the intake. You cant diagnose a motor as blown based on slight loss of vaccuum. You need to either confirm the bad seal with a compression test or to check everything else that it could be.
Spark plugs can dramatically effect how your car runs. Even enough to cause a small change in vaccuum like yours.

 

yea my fault not air temp, i meant water temp, ill be changing the sparkplugs over the weekend, ill see if that changes anything. if not ill bring it in to get the compression checked, if i didn't happen to get a leak in the intake, what are the most common spots?