Super exhaust set up

[Dragon87]

I am working on a super exhaust set up.  I am looking to put a cherry bomb after the main cat, the pre cat is gutted, and put a super trap muffler out the rear.  Both are straight through mufflers so there should be no problem.  The cherry bomb should give me the snap, crackle and pop and the Super Trap will give me the deep tone and looks.

 

If there is anyone who feels I am doing wrong in installing this please say so before friday and include way you think the way you do.

 

Thanks

[chubacca_tsi]

i had a cherry bomb muffler on my car for a while and it had a nice rumble to it.

[artinist]

i had a 3" suppertrapp on mine. its too freakin loud. i had no cats. i wanted to run without the caps but it was too loud so i had to put the caps on to quiet the thing. and with the caps on I think its the dumbest muffler next to thaoe "tunable flute" crap those ricers use on hondas. i had it from my corvette days thats why I put it on. i dont recommend it. dont try to recreate the wheel. get a 3" setup from kelly with either a magnaflow, dynomax or Ractive 3" straight through polished stainless steel muffler.

[shift1313]

i use a dynomax bullet with no cats, 2.5" all the way from turbo and it has a nice sound to it.  its deep down low but you can hear the turbo and its sounds great up top.  I agree about the supertrap.  I havent put one on a car but they are loud.  if your looking for deep its not the way to go.

[Questsi]

dont try to recreate the wheel. get a 3" setup from kelly with either a magnaflow, dynomax or Ractive 3" straight through polished stainless steel muffler.

 

 

That's right on the money, especially the wheel part ;D  The 3" that Kelly sells is by FAR the best buy that any of us can do to these cars.  I'm running mine with a cored cat and Ractive muffler.  It's suprisingly quiet at idle but it screams at WOT.  The best thing about this exhaust is that it gives you a solid foundation to build on, for an unbeatable price.    

[Dragon87]

Well,  I currently have the cherry bomb out the back.  It is not in line.  The cherry and the super trap look the same looking through them.  I plan on having it all done prior to nopi so you will get a chance to here for youself.  If it has a terrible sound I will have it off by Nopi too !!

 

:-)

[Yellow_quest]

I think the G54BT sounds great thru a 3 inch pipe...no cats, no mufflers,  no BS. I mean it dose sound Stroked form the factory (3.86in stroke!!!   ).  Why would you drop 2 back pressure inducing devices in a row on a turbo car anyway?  the turbo is your muffler FYI, it chopps up the Exhaust note.

 

 

I'm not diss'n ya here, but  ZERO backpressure behind the turbo is the goal. Better spool-up and a wicked Exhaust note under 1/2-WOT

 

 

my 2.6L worth

 

 

Yellow_quest

[Dragon87]

Both mufflers are 3" straight through and bigger then the exhaust tubing.  Where is the back pressure in that?  It  would simply be a method of exhaust tuning.

[Quest4Power]

Both mufflers are 3" straight through and bigger then the exhaust tubing.  Where is the back pressure in that?  It  would simply be a method of exhaust tuning.

 

 

there's no more than with a 3" straight.  and full 3" straight sounds ok, for a racecar.  but for street driving don't do it.  i drove my car that way until i got my N1 style muffler and it sounded like arse just driving around.  with the N1 knockoff it has a nice low rumble at idle and a smooth low exhaust note while driving, but not obnoxious.

[FastEddie]

I've been running a 2.5" pipe from the turbo back...No muffler, no cats, hella noise.

I love it, shotgun noises from 3k-2k rpm during downshifts.

Only reget, i should of got 3" pipe, upgrade is in the future...

Looks super sleeper from the rear of the car, just a small 2.5" exit...no SUPER MONSTER CHROME muffler with 12inch tip to scare the cops.

Just thought i would put some info....most are scared of straight pipes.

 

-Edward

[shift1313]

im gonna have to disagree about the no backpressure thing yellow quest said.  your right on one end. you dont want to small of an exhaust but you dont want to big.  you want good enough velocity to get the exhaust away from the turbo or else it cant do its job effectively.  2.5"will support up to 400hp or so, and 3" is optimized aorund 700hp or so.  im not saying you will notice a big or small difference between the two but if you have a short big diam pipe after your turbo it will not be good in the higher rpms but it will spool up quicker.  there is give and take about it all.

[Tim_C.]

Well, the 3" exhaust really doesn't come into play until the high RPM. You won't be actually using the extra flow capacity of the 3" until 6K+RPM. Under that, and the 2.5 is big enough to allow for the same spool, if not quicker spool than the 3". Going from stock to 2.5 spools faster. Going 2.5 to 3" does not.  There is a limit of tube diameter where the backpressure won't be any less for spool, and low RPM performance. 2.5 is that limit. But, 3" flows much better for more power above 6KRPM. That is where many of guys who have 3" don't go to, so really, they don't need the 3" for anything but a better tone.

Allbeit, a BIG turbo would take advantage of 3" to help spool, so there are exceptions. A 12A will not spool faster with a 3" exhaust over a 2.5. 3" will spool it faster than stock though.

I have a 2.5 mandrel aluminized pipe exhaust on my non-IC car. No mufflers, or cats, but a Monza resonator tip. My self imposed redline is 6K, so I wanted to try the 2.5 on it.

I have 3" on my .075 overbored TSi. Stainless mandrel all the way back, with an electropolished downpipe (polished on the inside for maximum gas flow). Downpipe to me, means all the way down, so the flange points under the car straight back to the rear, all in the same piece. I will be the first to tell you, that thing is overkill, but it sounds better than any exhaust I've ever heard, and so says most people that hear it. The engine revs to 7500RPM with ease, and some of that is contributed to the big exhaust. You really need an engine that can do it of course, but the power increase is more up high with the 3". Above 6K RPM is where the G54B power can go way up, and be the difference in winning or losing a race with a heavy hitter. That's the advantage of the StarQuest over most any other production car in its class.

[ConquestTSi]

If this is the case and the advantage between 2.5inch and 3inch on a stock 12a isn't noticeable before 6k+RPM, then why are so many going with it?  I wouldn't waste my money if no specific advantage was obtained between the upgrade.  Of course, this is coming from someone with stock exhaust so I can't comprehend either of the two.

 

Just a question, I just don't see the answer at the moment.

[GoldNBlack]

A very good read that will hopefully answer the 2.5 vs. 3 on turbo'd cars debate:  

 

http://www.vishnutuning.com/exhaust101.htm

 

 I had to justify my 3" exhuast purchase to myself...

 

 

Steve A.

 

14G-TD05H dumping into Heron's beautiful 3" SS Exhaust.

[artinist]

excellent document. very correct.

[Tim_C.]

I agree, very good explanation. I should make that a sticky.

[stiggity]

Cobra:

To add to the conversation. I "had" an HKS downpipe, into a 2.5" Cherry bomb, all the way back into a Magnaflow 2.5" Muffler/Tip. And got more compliments on that exhaust system, than ever before. Very quiet at idle, and a nice mellow/smooth sound during rev's. Once under boost,it sounded like a Jet taking off. PSHSHHHH!!!! no rumble, or crackle, just PSHHH..  Everyone would tell me "dude!, your exhaust is really loud" and it was all PSHHH! I now have a new setup from the cyldinder-head to the tip, but that setup was awesome. I was running a 19c from TEP. Now am running a T4 with a header, and External WG, 3" Exhaust. Oh, yeah, with 3" exhaust, it has to be done Right, or you run into clearance problems..

 

-stiggity

[chiplee]

im gonna have to disagree about the no backpressure thing yellow quest said.  your right on one end. you dont want to small of an exhaust but you dont want to big.  you want good enough velocity to get the exhaust away from the turbo or else it cant do its job effectively.  2.5"will support up to 400hp or so, and 3" is optimized aorund 700hp or so.  im not saying you will notice a big or small difference between the two but if you have a short big diam pipe after your turbo it will not be good in the higher rpms but it will spool up quicker.  there is give and take about it all.

 

I'd like to hear your thoughts on the turbo exhaust article that was posted after you posted this Shift1313.  Would you agree that you were applying N/A logic to a forced induction setup?

[shift1313]

not at all chip. Very good document.  it still doesnt justify(in my mind) the need for a 3" exhaust because of the way our motor is(on small turbos).  

"The idea is to get the exhaust velocity up quickly, to get the turbo spooling as early as possible."

 

Most of the turbos we run have a 2.25" turbine exhaust size.  running a 3" pipe reduces the velocity as opposed to a 2.5" pipe.  As tim and I said. 3" on a stock turbo is not optimized.  a 2.5" will give you enough velocity to get the exhaust away from the turbine and reduce the backpressure.  while a 3" will 'build up' so to speak.  it will probobly boost quicker, a few hundred rpms. but i think(being key) that up top two identical cars, the 2.5" will win up top.  

 

I will be the first to say a larger turbo will justify 3" but it has to be custom suited to the application.  most of the people want to know if 3" is better then 2.5" on stock turbos or 14g, etc.  as per that article, no.

just my opinion on the subject so nobody take this as the holy grail of exhaust knowledge.

 

oh and chip the hp numbers i said were for the starquest.  alot of turbo cars rev way past the 5500rpm detriment that the "stock" quest suffers from.  i still stand behind my previous statement 8)

[shift1313]

i just wanted to add without modifying that how many of us can make a horn shaped exhaust? and how many of us could stand the noise;)  i could just see that going down the road with a horn sticking out the side of the fender:)

[chiplee]

the idea of the horn shaped exhaust is used solely to illustrate a point that bigger is better with turbo exhausts??  you must have understood that, but it doesn't look like you read very closely from your response about velocity.  Just my opinion though, no biggy

[shift1313]

the idea of the horn shaped exhaust is used solely to illustrate a point that bigger is better with turbo exhausts??  you must have understood that

 

The way i took it, the horn shaped exhaust was to get the exhaust gasses away from the turbine and by increasing the diameter farther away you reduce the back pressure.  

 

bigger is better but with a soley bigger pipe there would be no velocity.  and by no thats figurative.  

"Downstream of the turbine (aka the turboback exhaust), you want the least backpressure possible. No ifs, ands, or buts"

 

thast why my exhaust is two pieces, a down pipe and the second half is all one piece, no cats and a bullet muffler to reduce the backpressure and very mild bends.

 

"At 250 hp, 2.5" is fine. Going to 3" at this power level won't get you much, if anything, other than a louder exhaust note. 300 hp and you're definitely suboptimal with 2.5". For 400-450 hp, even 3" is on the small side.â€"

 

for a normal high reving 4 cyl, for the 2.6. the game changes.

 

"As you can see, the backpressure penalty of running a too-small exhaust (like 2.5" for 350 hp) will vary depending on the match.. "

 

there are so many different parts to the exhaust equation and we can only optimize a few, the exhaust will never be optimal, there will always be things that will make it better.   the way i see it, the best you could do with stock/small turbo is a 2.5" down pipe that tapers out to 3" by the time it reaches the next piece. then from there a short dump if anything else.

 

 

again this is aimed towards stock/smaller turbos which most of the guys upgrading are running.

again its my opinion but i dont want people thinking that cause you have 3" exhaust on a 12a thats some instant recipe for 300hp.  there is alot that goes into it as chip can tell you.  you have to setup everything on your car to work with what else you have, intake, head flow, etc.  

 

 

 

(((chip, if you want to discuss this more i will be happy cause im sure we could go on and on back and forth so just shoot me a PM if you want, that way we dont take off on this thread:)

[89onaquest]

Well my take on sizing, is similar to shifts...

 

the max you should go is 1/2" over the outlet of the turbo.(right out of the outlet)

If nothing else, just the DP should be 1/4-3/8 bigger.

Then after the D/P you can step up to the 2 1/2. Then after a few feet, go to the 3".

 

a gradual increase will have no, or very little effect on velocity. In most cases it keeps it climbing steadily and stabily.

However, a sharp increase will create a "dead spot" in flow, that shear mass flow has to overcome. And that is backpressure.

 

People keep saying

"because its turbo'd it's different", sorry, but rules of flow are rules of flow. Same with velocity.

[marksweet]

I've run a 16G/19C and now a 20G all with Kelly's 3" pipes and the WalkerDynomax 3" in & out muffler and wouldn't do it differently. Mark

[johnfjamerson]

I wouldnt put a cherry bomb right behind the cat, It will only last for about 2 months before it gets burnt out. Those things arnt that great.