scotty305

iTrader: (2)

So, the other day I noticed that my RX-7 felt unusually slow. I could hear the turbos spooling, it just wasn't accelerating as hard as it should. After reviewing the datalogs stored in my AEM EMS, it seemed like I had a major boost leak: notice the blue trace (MAP) never goes much higher than 0 PSIg.





I spent a while under the hood, revving the engine and feeling around all the stock couplers and charge pipes, but didn't find any boost leaks. Finally I decided to just take all the intake piping apart and make sure all the couplers were fastened securely. Imagine my surprise when I found the intake coupler for the front turbocharger was collapsed:




And here's why:


The black piece of plastic fell out when I opened the airbox:


This is where it goes:



The piece of plastic looks like it split where it had been attached. It forms the muffling chamber for the ACV 'exhaust', which is the source of that 'moo' sound. I've removed the OEM pipe that comes from the airbox and replaced it with a chair leg stopper, per DaleClark's recommendation. I wonder if the added pressure from the stopper caused the plastic to split and break off. Luckily, I had a spare airbox lying around (picked it up with some other parts), so I installed it and the car is now back to normal.




This is now one of the weirdest RX-7 stories I have, but it ended well. On another note, I haven't been using the ACV, the output from the EMS software is always turned off, and I'm considering buying an ACV blockoff plate so I can remove that muffler chamber from the airbox. It is taking up quite a bit of real estate inside there.

-s-

adam c

iTrader: (2)

Wow. I have never seen that before. No wonder it wasn't running well. At least you found the problem, and were able to fix it easily.

You really should modify that airbox ......................

scotty305

iTrader: (2)

Adam, your "cheap bastard" intake is definitely on my list of stuff to do, but I'm too cheap of a bastard to do it just yet. I might be able to make you an offer you can't refuse, however. Sending you a PM.

-s-

Kento

I've seen the stock soft accordion-style intake hoses collapse before, but not because of the air bypass valve chamber coming apart like that. Yikes. Why did Dale say to block off the exit hose from the stock airbox?

adam c

iTrader: (2)

Scott,

With a properly modified airbox, there is really no need to remove the "muffler chamber". The increase in airflow kind of makes it pointless. I'm not sure you would gain anything by removing it from an unmodified box either.

jeff p

the cheep bastard kit is the best bang for the buck. don't re install the box without it. right now most of the work is done.

Jeff