otakurx

Well it's not entirely done yet, but I figured I'd share the pics I have of it anyway. All that's left is a couple hangers and the tips, should be picking up the car tomorrow. Now these photos were taken with my BlackBerry while they had it fitted in place, you'll notice the supports on the mufflers in the back. Anyway, tried my best to make them look good.

PS: Sorry if this should have gone into one of the performance forums, but I really wanted to share.

xexok

I take it you had one custom made? What kind of mufflers, how big are the tubes? If not what kind of exhaust is it.

otakurx

It's all custom, 2" piping on the header, which is an additional 12" long. Collected into a 3" pipe that has a resonator in it. It then splits into 2 2.5" pipes that go into the chambered mufflers and then it will go out the back thru 3" outer diameter tips. I'll put more up when I get the car back.

otakurx

Here are the shots of the tips, it's all done and running. Sounds great, kinda like a throaty FC lol. Has a nice grumble and pop on deceleration. Will try to get sound clips over the weekend.

xexok

Isnt it a bad plan to go 2" to 3" to 2.5" back to 3"? I thought in general you wanted the same diameter all around so the back pressure stays the same and exhausts flows more freely? Nice looking tips though.

xsnipersgox

the exhaust will if anything choke at the 2 inch, so it wouldn't matter much anyway past that.

otakurx

well you have to look at it in 2 ways, volume of the pipes, and pipe velocity. I mean the multiple smaller pipes of the header, three 2inch pipes, actually can flow more volume then the single 3" pipe as can the two 2.5inch pipes. Now as I go from 1 big pipe too 2 smaller pipes, the velocity would change while the effect volume would be more then enough. The tips have an inner diameter of 2.5" so it doesn't go back to 3".

It's a similar idea as to why you see the duct diameters change in an A/C system in a building. the volume of gases being moved in our exhaust shouldn't change before the end, so splitting out into two 3" pipes to the mufflers would be a waste and could even slow the exhaust and make it substantially louder. It also must be taken into consideration that unlike a 4-stroke piston engine, rotaries don't need back pressure. I've actually found that due to the nature of a rotary engine is very similar (if not in many ways identical) to a vane pump that the engines benefit well from a well maintained exhaust velocity. So I tried to pay careful attention to maintaining a near consistent volume through the exhaust.

That's how I came to 3x 2inch into 1x 3inch then split into 2x 2.5inch pipes and out through 2.5inch tips.

xsnipersgox

sorry i was being stupid and not thinking too much.

i went and forgot this is all sub sonic flow so ya, no choking here, bigger exhaust = less back pressure. pretty much only thing that we needa care about here.

otakurx

I would think sub sonic or not, you'd still have choke points, but going larger then 2" piping on the header would be useless since the openings in the housings are barely 2".

otakurx

Figured I'd just use my old thread here to report some log findings since I've finished everything on the car prior to working on tuning. First as a refresher I'll list out simply the few things done with the car.

Mod list (simple one):
AEM Intake
BHR Coil Kit
180*F Thermostat
Exhaust from engine back designed by me off information from here and from my old 7

Log information (only did Min/Max/Mean nothing indepth yet):
Lambda is the same, .760 to 1.360 with average at .996
Engine temps go no higher then 178*F mean temp is around 176*F
Intake flow maxed at 29.96lbs/min in 3rd gear (tho I don't think I ended up at 100% throttle so could go slightly higher but I wouldn't expect much more)
Exhaust temps seem to stay below 1786*F
Timing is normal -5* to 44*

Now I don't do the butt dyno, but I will say some observations since completion. Idle is smooth as silk at 804RPMs with excellent throttle response. I've noticed little change between 2000 and 4000, better pull then it had prior but once you get about 4000 it really starts to open up more. I've noticed the most from 5000 to around 8800. In that range pull stays very strong, with a much more noticeable squat in the rear (RB springs and Tokico D-Spec shocks).

Oh and lastly, I'm seeing an average of 20.3mpg.

ZumnRx8

Wow, I bet you saved a lot of money by doing a custom exhaust and Im sure it sounds Good and the Tips are nice also, but The welding Job on that Thing looks like CRAP. I hope you didn't pay for that crappy *** welding... This is what Welding is suppose to look like... this was all done by hand. There was no need for all the 2-3-2.5 piping or whatever. I seriously hope you did it yourself, because if you paid for it... well.... that sucks.

otakurx

So you ran 3" piping in the header? How did that fit in the engine bay? The exhaust sounds amazing and if I did it, it'd prob have fallen off already lol. The guy who did do it covers it for a full 5 years.

Oh and I forgot to mention, the only DTC I'm throwing is a Secondary Air System, I figured it'd finally pick up on the lack of cat but it seems to not care.

MarcMiller

iTrader: (1)

Please mind my n00bness but what is the different color exhaust tip for? or is it just for looks?

looks good *** hell don't get me wrong just curious.

ZumnRx8

^The different color tips are TITANIUM... you know the same **** that the SPace Shuttle is made of They are ribbeted on because Titanium cannot be welded There are fakes out there... but these are real, How can you tell? Try Welding them on...LOL In the end yeah they are just for looks

MarcMiller

iTrader: (1)

Thanks for clearing it up

Spoolin8

iTrader: (2)

The welds look fine. Aesthetically they dont look good (who is going to see it anyways) but the welds overall look like nice solid welds that honestly are probably stronger then the greddy example you showed. You think the spaceship is not welded together titanium can be welded, its just tricky.

silverbullet05

iTrader: (7)

otaku: how much did the whole setup cost you? I'm interested in having a shop fab one up for me too, but i'm weary that it won't end well. Nice choice in tips btw =)

adamwzl

iTrader: (3)

Correction Titanium can be welded only to Titanium metal and can only be welded a maxium of two times.


Also I have a Full titanium JIC but I removed the TI burnt look because its to ricey imo.

otakurx

It ran me a grand all together, not a bad price in my opinion and it sounds amazing.

rodjonathan

iTrader: (6)

not crapping on your exhaust but you could get a great exhaust for a grand easy ... is there another reason you went custom instead of bolt on? just wondering