Hahaha, a very valid point!

 

Yeah, I can stuff my arm into my catback up to my shoulder, if I ever spit a particularly huge fireball I'll have to check to make sure it wasn't baby or kitty

 

OK, found a better combo for your 4" megaphones. I was under the car tyring to see if a 4" Y would be possible but there is only about 9" of width and then theres turns and less space further down. So here is my solution:

DNA full throttle collecter muffler in place of most of the strait pipe. There is no packing to wear out and it's 4" diameter end to end. Now for the muffler, you can choose between Borla XR-1 "multichamber"" (not sportsman) or for full flow Spintech muffler gauranteed to pass NHRA DB sound requirements.

I'll buy that for $1 (send tips via paypal to GoRacer@yahoo.com)

 

How does the dna muffler quiet it down?

 

http://www.dnamufflers.com/DNA/contest.html
http://www.jegs.com/webapp/wcs/store...92781_-1_10265

 

I've had two Ideas...

A: 4" Dp-> MP -> reduced back to 3" and two mufflers.

B: full 4" exhaust running a Edelbrock, or similar Diesel performance muffler.

 

I drove my FD around the neighborhood yesterday, and surprisingly it wasn't as ridiculously loud as I thought it would be. My brother stood in the front yard and listened, and said that my new setup may be a bit quieter than my old setup. Keep in mind, I am not tuned so I was shifting at 4500ish rpms and not really boosting.

old setup: 3" dp----->3" mp------->3.5" HKS super drager with hollowed out muffler
new setup: 4" dp------->4" resonated mp------->4" magnaflow catback

 

My car has a large turbine housing, 4" downpipe, and rotary performance race exhaust which is a greddy system and is 3.75" pipe to their race muffler no cat. It comes with a silencer, and does make it ALOT quieter, but then wont allow it to boost or flow well at high boost/rpm's...so I just leave it out. It is loud and it gets annoying at longer cruises. If this were a daily driver, I def. would not have this large of an exhaust. ErnieT has the EXACT same exhaust setup. As far as boost creep, I have a Tial 44mm and I get boost creep with the 10 lbs spring just on wastegate...it starts off at 10 then by redline I am 21 lbs boost...I need a bigger WG

 

Good info, thanks.

Been meaning to ask you----i am thinking of running c16 fulltime. I have the tial v44mm wg as well, according to their website it comes already equipped to handle race gas, so I'm not too worried about that. Of course I have no cats, so the main thing I am concerned with is my Bosch o2 sensor. Based on the other thread on race gas, it looks like I need an NTK sensor. Which one are you running?

last thing, I was told by a shop owner that they've had problems with cars on leaded race gas that are allowed to sit for awhile (like a month or so)......the secondary injectors get clogged from disuse, leading to them having to be removed and cleaned. Any input on this with regard to your FD?

 

Hey Rich,
Yes, the wg has no issue with race gas. I originally ran the bosch 4.0 sensor which is their race sensor, supposedly more sensitive, but are expensive. They do not like leaded race gas, esp if you use a 2 step, that absolutely destroys them, or any type of backfiring shockwave. I currently use the cheaper bosch 4.2 because I can get them at work for cheap. I do not use them for EGO corrections because once they start to go bad, it messes with your part throttle tuning, thats why the tuner gets everything right initially and once the tune is done, nothing really should have to be changed. Typically though, when the 4.2 start to go bad, they tend to read leaner, so if my fuel pressure is still good, I will just swap another sensor to verify that the a/f are still in check, if they go back to normal with the new sensor, then I know my sensor was going bad, but if it doesnt change, then something else is wrong, like a injector isnt functioning properly. No doubt about it, the NTK sensors are really good and really sensitive and can hold up to the race gas alot better/longer than the 4.2's so the intial expense would be worth it, but if you get the tune right, then like above, you shouldnt have to worry about it with the 4.2's. Just keep an eye on your fuel pressure under boost, or do what I do...swap them out when your a/f start to change from normal.
I usually let my car sit for a week, and then run it just to keep everything in use...same with ernie. I have heard that it will build deposits in the engine itself if let sit long enough, not sure about the injecters though, because you still should have residual fuel pressure in the system after the car is shut off and not exposed to air in the sytem, but after a month or so , not sure, it might bleed back, never have let it sit for that long and not run it. And I got tired of paying for C16, so I switched to 110 leaded race gas at less then half the price of the C16 and dont have to get it shipped, local pump sells it. I run 21 lbs no issues, but if I go to the track and run full boost, I will use C16.

 

Thanks for your interest in DNA Mufflers.

First let me saw that DNA Mufflers are 100% stainless steel. The body of the can is 16 gauge, the sound diffusers are 16 gauge and on the Race Series DNA Muffler, the Vent Tube is 100 thousandths wall for heat dissipation.

Rotary engines make lots of power, but also lots of heat. Our bodies last much longer than competitor's according to some feedback from other rotary customers.

As for noise reduction, it is all relative. I don't have specifics on rotary engines, but on a drag race car going from open headers to a pair of our race mufflers, we dropped the sound produced by over 14 decibels. That is dramatic.

We have sounds available on our website (although there are not any rotary ones). If you decide to use a DNA Muffler, I welcome you to send me a picture of your car and a sound clip and I will put them on the DNA site.

I hope I have answered your questions, if I have not or you need more answers, please do not hesitate to contact me.

Thanks.



Randall Perks, CSP
Technoflange Inc.
www.dnamufflers.com
randall@dnamufflers.com
905-683-3785
905-683-4249 Fax

 

^ Cool!

I think I might ditch the blank cat and try one of these out and see how it does.. if it's still too loud I'll consider using two.

I'll post results once everything is up and running.

 

I got some more seat time with the car today, and I really like my new exhaust setup. The sound levels are tolerable, and it sounds mean as hell. I received compliments on the sound of the car from some guys on two different occasions, and had a bunch of mechanics working on some mk4 supras come out of their bays to check my car out as I made a U-turn.....I obliged them by ripping on the car a bit

 

When do we get to hear, Rich?

 

Not sure if you saw this from my other thread:

http://videos.streetfire.net/categor...a70165c981.htm

 

Oooh, no I didn't. Forgive me.

Thanks for just making me want to blow another grand on a 4" exhaust. :P Sounds great.

 

Dang.... That sounds waaay better than I thought it might..... Sounds great Rich.

 

You should hear it at full song at 8200 rpms .

Thanks for all the positive comments guys, I was really looking forward to taking the car out this weekend but it looks like nothing but rain......

 

Our engines aren't set up that way so we are not going to see any scavanging benefits in exhaust other than perhaps equal length PRE turbine primary tubes on the header, and even the specifics of that are beyond me because I dont know the delay and firing sequence of each rotor's chamber.

Well, turbo cars can actually scavenge much better than NA, but it happens very differently of course.

If you have a VERY well set up turbo the intake pressure (boost) exceeds the exhaust back pressure and you have positive scavengine as the intake charge pushes the spent exhaust gasses out the exhaust port during intake/exhaust overlap.

Ways to get this effect-

Huge post turbo exhaust- high pressure differential between turbine wheel sides means less engergy to drive turbo.

Huge wastegate w/ its runners entry in line w/ exhaust flow- more exhaust out WG also lowers exhaust backpressure so intake presssure is higher.

Low pressure drop IC and intake- turbo has to work hard to make the boost loss from pressure drop, turbo working hard means more exhaust backpressure.

Small((ish) primary tubes on your turbo manifold- seems wrong, but your WG is now really helping flow and the small primary tubes boost exhaust velocity so it hits the exhaust wheel going fast.

So, a small frame turbo (or a bigger frame low A/R big turbo w/ flange cut back for smaller runner area) stuffed w/ a big exhaust wheel can get you the high velocity you need before the wastegate opens since the huge exhaust wheel flows well enough that the high overlap motor needed doesn't choke before the wastegate opens to relieve backpressure.

Sorry that was so long, but it is all related to the same thing the large exhaust is for. Getting into that magical turbo realm where you get scavenging!