Cherry Bomb - Vortex!

[taylorRichie]

If he's talking about installing a high flow cat, I doubt he wants back pressure... He's probably wanting back pressure specs to possibly determine how loud it'll be??

[SilverBullet75]

Guys,

I'm at a loss as well.. common sense tells us that less backpressure equals benefits, not negative results!... but...

All I know is that when I went with the Flowmaster Super40, which has much more open flow than stock, I lost a lot of low-end torque, some hp, and gas mileage was terrible. (also confirmed by VCross007 when he tried the same setup)

I put the stock muffler back on, and everything was great again... but too quiet.

So, I found a happy medium... a similar design (chambered), but with fiberglass surrounding the chambers (which should add some resistance).
So far so good! Throttle response seems improved. Torque is GREAT. Gas mileage (so far) is definately improved.

So, I don't have any dyno data to "prove" it... just experience.

I'd also like to apologize to VCross007 for leading him to the Flowmaster prematurely...

Littlebeast,
RE: "I am looking at 3 options:
-MagnaFlow part# 14378
-Cherry Bomb part# 88115
-FlowMaster 50 Series SUV part# 524554"

My Cherry Bomb Vortex part number is 88101.
Also, according to the muffler guy, the FlowMaster 50 series is pretty quiet... almost like stock with a little bit of a "throat" to it.
(I never looked at the MagnaFlow... always heard they were too raspy/loud)

I'll try to get a sound clip soon... maybe today.
Thanks!

[Kenny]

The fiberglass packing in the muffler, or resonator, does not add resistance per se or affect backpressure. All it does is dampen the reflecting sound to help reduce the resonance and blend the exhaust note. Extra baffling in the muffler and smaller pipes will create back pressure.

Theoretically we should get some minor improvement in performance with higher flowing exhaust through the scavenging effect it is supposed to make. Meaning it will help "suck" the exhaust out of the piston chamber as opposed to letting it be pushed out. I guess this is supposed to reduce the effort the piston makes on its second rise to exhaust the cylinder - in essence improving efficiency.

Were the duals and high flow cats and open mufflers will shine is if you improve intake air velocity/amount. i.e. better intake, and ultimately, a supercharger.

I'd say the more insulation the better as opposed to constraining flow with baffles (my old Morgan tec had no insulation and basic baffling so it liked to develop a nasty resonance at a specific rpm due to harmonics - insulation dampens this effect). I think Magnaflow mufflers are on the loud side due to their goal to maintain high flows with minimal baffling. From my experience, they should be complimented with a resonator or glass pack to tone em down a bit.

Personally, I'd lean more to a heavier muffler just to get the sound levels down. If you don't plan on supercharging, and want a growl, I think one of the heavier models by Flowmaster, Cherry Bomb, Aeroexhaust, should work.

I's say our biggest challenges are being 6-cyl (we all really want that 8-cyl purr) as well as a very short underbody with little room to play with pipes and such.

[Ascinder]

Backpressure is fairly straitforward. More usually increases torue, but decrases horsepower and vice versa. There is obviously a sweetspot where you get the best of both and sound is always a concern. This is why you hear people on here adding dffusers and restricters, too much free flow equals no low end get up and go, while too much back pressure makes you engine have to try and "pump" out your exhaust more than normal. Try removing you muffler and driving around the block. You will feel a tangible loss in the acceleration/pickup department.

[VCross007]

Yea, I'm all stock, I did the elbow removal plus k&n filter. I noticed good mileage and hp gain, and also when i replaced the pcv valve. When i put the super 40 on i noticed a decrease in low end torque. Also , it seems to shift between gears around 50mph. If i let up on the gas, the rpms go up above 2k, but if i put my foot back down, they'll go up to about 2300 or so then shift down into 4th. it's really annoying and i dont know what to do. I get about 300 miles to the tank, im currently at 283 and have a quarter tank left, but ill fill up tomorrow to be safe. I want to go to borla, but i want to make sure that muffler that ldub has has better backpressure. I guess if you have too little bp, it has a negative effect and flows too much. who knew

[VCross007]

oh and to silverbullet, it's cool man. with cars it's all trial and error. you just keep tryin till you find the muffler u want. I just want something loud and mean

[taylorRichie]

That's why I've always like supertrapp exhuasts. You buy a muffler, then tune the backpressure, and sound to the "sweat spot" for you.

[Ldub]

I just want something loud and mean

If you lived closer, I could introduce you to a couple of my X's.........

[VehiGAZ]

according to the muffler guy, the FlowMaster 50 series is pretty quiet... almost like stock with a little bit of a "throat" to it.

I can tell you that this claim is either ignorant or a straight-out lie...

I put a 2.5" in/out Flowmaster Delta 50 on my VX and it is brutally loud. 200 yds down the road, I would have brought it back to the shop for them to yank it out again if I hadn't had to drive to PA for a business trip that evening. It has since mellowed out slightly, but it's still extremely loud and sometimes pretty harsh sounding.

On the other hand, I found that it improved off-the-line acceleration noticeably, and it certainly let the S/C breath easier at the top end of the rev range.

Hearing this nice recommendation for the CB Vortex, I might give it a try.