anyone in socal know how to TIG the flanges for me???
not too familiar with welders

 

Here's my DIY exhaust:



Here's the How-To: http://www.robrobinette.com/S2000ExhaustPipe.htm

By joining up at the widest part of the split a 2 1/2 inch pipe fit perfectly. I am going to have to add a second hanger on the long exhaust pipe to keep it from swinging toward the passenger side and hitting the bumper's exhaust exit.

This is much, much quieter than the cutoff and turn down I tried at the split. I'm running a resonated test pipe and no longer need ear plugs on the track.

Don't forget that Summit Racing and Jegs have a lot of cheap mufflers and tips you could use.

 

Very interesting Rob! I considered that very thing as I don't like how the shorty version vibrates the entire floorpan of the car around 3000 rpm. I didn't expect it would actually drop sound levels in the car very much! That's a nice bonus! I'd gladly add 3-4 lbs to cut sound levels in the cabin for street driving.

I was going to use a triangular AP2 exhaust hanger by having two prongs on the exhaust hanger rods to keep it from swinging around so much.

 

The triangular hangers setup is the way to go to keep it from swinging in either direction. I was very surprised how much quieter the pipe-to-the-back actually made.

If you have a cutoff under the car and you're getting a loud buzz around 3k, try holding the fuel pump cover while revving the car at 3k. My cover was buzzing really, really loudly. I pulled the 3 screws and added some silicone sealant and now it's silent.

For long drives the Bose QC2 active noise reduction headphones made the cutoff exhaust much more tolerable. I used it for my 5 hour drive to and from VIR in February and I would have had to cut my wrists without the headphones.

P.S. If backpressure doesn't affect torque someone should tell Yamaha/Suzuki/Kawasaki because they all use servo controlled valves in their motorcycle exhausts to vary backpressure to widen their torque curves.

One last thing. If the turn-down exhaust tip at the rear of the car catches on with ricers you know where it started--could be the next-big-thing

 

NO, the valves aren't to induce back pressure it is to speed up the gas flow. A higher velocity improves scavenging.

That's also why you lose torque when you use too large of an exhaust pipe.

With a 60mm main pipe you don't need super large pipes after the split. By having 2 60mm pipes after the split you've effectively stalled out the gas flow. That's why singles dyno with more hp.

 

It's not the valve's purpose, but it does create some back pressure. I agree increased velocity improves scavaging but the back pressure is a byproduct.

 

Cool, a differential heater.

 

An update on sound levels...

At 75' at the end of a straight into a 1st gear downshift sweeper, my S2000 with this setup registered up to 89db and averaged 87-88. Not bad at all!

 

If you guys need an official weight of the mufflers cut off at the 'Y', it's 41.6lbs.

Pretty hefty!

Welding mine up this Friday, but you wouldn't know it by looking at my car from the rear.

 

I flipped the turn down around since the picture was taken.