Mule22

Running W2W next year with NASA and thinking of removing my exhaust and bolting up a straight pipe. Am I at risk of losing hp or torque?? Any real world experience? Or numbers or even opinions?

ndogg

I don't have any hard evidence. But I would think you will only stand to gain both HP and TQ. I am running a straight pipe chopped right after the axle and I made 197hp on a nasa approved dyno on AP1 with everything else stock (including intake).

Driven

https://www.s2ki.com/s2000/topic/617...#entry15767712

Gain of 3-5hp it appears, as well as losing 40-50lbs off the back half of the car.

Mule22

I should clarify that I do already have a fancy Ti single exhaust 70mm blah blah..... Not sure of the name brand. Not worried about noise either just if it will affect power in any way. I'm talking about a straight pipe attached directly to the ceramic header and turned down right behind the driver. No cats, resonators, or mufflers.

Mule22

Ndogg is that what your running?

ndogg

I have a test pipe (no cat) but the stock resonator is still there. Turn down added just before it normally splits into 2. I have it setup with a vband so I can swap between the turndown and stock mufflers with 1 bolt.

CKit

That's the CaptainPants mod. Used to be a standard autocross mod, but disallowed when "street" rules come into play.

robrob

A straight pipe is extremely loud. You may exceed noise limits and you MUST wear ear protection. I recommend at least install a straight through muffler.

My stock header with modified exhaust. I'm using one of the turn-down bolts for the hanger:




Please no snarky remarks on my welding. This is one of the first things I ever welded but it's still hanging in there.

Mule22

Robrob is that the header flange in the very right side of the photo. This is similar to what I'm looking to do. Any noticeable loss of power????

robrob

Sorry, I forgot to mention that I run a resonated straight pipe too. It's to the right of the flange in the picture.

From my website http://robrobinette.com/S2000RaceExhaust.htm
Morroso racing muffler with 2 1/2 inch inlet and outlet. The muffler flows about 70% of the exhaust straight through and 30% goes into a spiral around the primary flow. The muffler will just slip over the stock exhaust with a perfect fit which makes it easier to join and weld.

It doesn't have any insulation to burn out so it lasts a long time.