Has anyone ever dyno tested a maxima with the exhaust removed completely? (and by completely I mean no Y-pipe no pre-cat just open air - like a dragster/race car) - you would lose some low end power because there is no backpressure at all, but you should also get the absolute maximum power gain that can be achieved by modifying the exhaust system. Of course you wouldn't be able to drive on the street but you would know how effective exhaust modifications can be.

 

Someone dynoed w/ no muffler. No real gains and alot of noise. Remember even though the muffler is off, you still have the cat and a long stretch of 2 1/8" pipe.

 

I saw that post, but what I'm talking about is no cat, no pipe(Y and B), no anything. That way you would know the maximum that can be approached with Y-pipe, high flow cat, and wide cat-back.

 

Your car needs a certain amount of backpressure to function correctly. And w/o a y pipe, the car cannot benefit from the scavanging effect of the other 3 cylinders. Not only will performance suffer greatly, there would be WAY too much noise and no provision for a 02 sensor. I doubt the car would run at all.

 

there are 2 O2 sensors right after the manifold and b4 the precats so If U remove the Y-pipe I'm assuming the ECU will freak out and report check engine errors.

 

In that case what would be the minimum configuration which would allow the car to run - just the Y pipe, no pre cat, no cat and no catback? Then that would be the theoretical maximum gain.

 

Say yoy leave the stock Y-pipe in place and relocate the )2 sensor to the y0pipe. Then you cut everything else off. You won't gain much if anything. Maybe 2-3 hp if that. The exhaust isn't that much of a restriction.
Now if you add an aftermarket Y-pipe and hack the rest off, you'd have about 8-10 hp over stock. The biggest restriction in the exhaust is the Y-pipe, not the pipe after it, or the muffler.

 

Min would be cat+some pipe for the other 02 sensor if you have a 96 year and up. Again no real gains for the amount of noise.

 

Which would still = very little, maybe 5-10hp if you are lucky. The noise to power ratio would be bad. Plus that sorta defeats the purpose of a nice and quiet maxima if you as me.

-Shing