EJ22 exhaust size / car dies when decelerating

[baccaruda]

I've searched, found little.

 

I had a 2" exhaust put on the wagon yesterday, no muffler yet, just straight pipe. Yes, it's a lot louder than I thought it would be - but that's not the issue here, I'll have a muffler put in soon.

 

I'm wondering if I should have gone with 2.25" instead. Dave (exhaust guy) recommended the 2" to me based on the horsepower output of the engine and on my indicating that the wagon would be driven normally most of the time. He said that larger than 2" would not provide enough backpressure.

 

Is it possible that the 2" has too much backpressure? Given that the EJ22 has so much low-range torque, I'm wondering if I should have gone with a larger size of exhaust. Granted, I'm not used to the way the car feels yet, but thought I'd get this straightened out.

[NoahDL88]

2 inch should be plenty big, and its not about the back pressure, its about exhaust flow velocity, you want to keep it between 240 and 260 feet per second for max power.

[WoodsWagon]

I'd say it was your neutral/ clutch switch. My EJ22 does it too, you're decelerating, then you push in the clutch and the engine just dies. I think it's because the PCM switches into no-fuel mode on decel, and when you push the clutch in, it takes it a bit to realize it needs to go into idle mode. Usually it catches it in time, but sometimes the engine is stopped before the PCM realizes it needed to swich to idle fuel map.

[baccaruda]

Thanks Noah.

 

91Loyale, it doesn't do it all the time. I think it's related to the lighter flywheel because if I let the engine slow down slowly it is less likely to die, and it won't die all the time if I let the RPMs drop quickly.

[offroadsubaruguy]

i havent finished my exhaust yet, but i am running the borla header on my 90 legacy as well as a light weight flywheel, the lightest i could find that runs it at around 11 lbs i think, but i have never had the problems you speak of.. i would look more towards the electrical/brain of the engine side of things..... i have never known a car to die from the exhaust being too big, you would just lose power instead, almost kinda like the feeling of a catalytic converter dying.... you might also want to check your fuel system, things like fuel filter and whatnot.....

[Subarutex]

RECENT YOUR ECU!!!

 

I have an OBX equal length header on my beast, with 2.25 from there back. I got it on last week, then last weekend drove to Vancouver BC for a car show. On the way up, everytime I had to slow down a lot, the car would nearly die, cause I took it out of gear and wasn't on the go pedal.

 

Dan and I couldn't figure out what was up.

 

At the car show they require you disconnect your battery. The next day after sitting unhooked for awhile we drove it home. No more dying! I think the ECU just needed to relearn and get stuff all sorted out.

 

Atleast thats the story I'm sticking to.

 

Also, real men don't decelerate.

[baccaruda]

lol. real men also don't drive cars with squishy brakes but I forgot to bleed the hillholder when I was bleeding the rest of the brake system.

I had thought to blame the xT6 flywheel as maybe it wasn't light enough to keep the engine spinning... but I'll go unhook the battery now. thanks!