Muffler ... location vs performance?

[Guest boosted]

Any disadantages to putting a muffler directly after the DP turns beneath th car. ?

are there performance advantages to be had by different locations of the muffler. ex . close to the engine or further away from the engine?

[Guest boosted]

I personaly dont think there would be any + or - to front or back but before I build the system Id like to know.

 

No exhaust( open DP) is how ive been running it for a week and its a beast but draws unwanted attention.

[Guest boosted]

thanks . Im sure there is a difference but nobody knows the answer. only difference is im the dummy who wants to know

[fl327]

ground clearance? You could always just run a straight pipe with NO muffler, isnt very loud on a turbo car, sounds pretty cool actually. the turbo itself tones and quiets the exhaust.

[randy 77zt]

i have a 3" magnaflow 19"long oval muffler underneath the heat shield for the cat convertor.i left the heat shield on because it gets hot where i live.i like the sound-quiet on the freeway unless you gas it.the magnaflow is kind of like a cheap borla-no baffles -just a perforated pipe & packing.baffles arernt supposed to be good behind a turbo.i dont like flowmasters.if you put a muffler in the back yoou cant get a big 1.i used 2 3" 90 mandrel bends behind muffler and a 3" chrome tip.nice mellow sound for a daily driver but some people might like more noise.

[materchan]

i have my 3" exhaust dumping right before the diff. it's a moroso spiral flow muffler. it sounds nice(possibly a little loud). i made a complete exhaust exiting in the stock place and with the same muffler the car was quieter than my very quiet NAsetup was. also i couldnt hear the turbo spool up as well, probably had more backpressure too. also my exhaust pops ALOT. sometimes it pretty much backfires, could be somwhat because of my AFR, but i think it has somthing to do with the shortness of the exhaust.

[EZ-E]

It might tone and quiet the exhaust with full tubing but no just with two bends off from the dp, I just fabricated my 3 inch dp, and its only on from the turbo to the middle of the door and it is quite LOUD.

 

Then again, the way you sound like a Mack truck going down the road is sweet too.

 

Mine will end eventually into a Dynomax straight threw muffler, they sound really nice.

[olie05]

I would think if you had the muffler on the downpipe and no other exhaust it would have no bends, and so the sound would travel straight through. With a full system and muffler out back, the sound is deadened by the bends a little. Sorry i don't know if it would have an effect on performance.

-Oliver

[ZROSSA]

Put the muffler as far away from the engine as possable. It will be quieter and lose less performance.

 

Douglas

[Xander]

at the back of the exhaust system the exhaust gasses are a lot cooler and thus a lot less in volume. So putting the exhaust at the back of the car has a performance advantage because there is less volume of air to go thru the muffler.

 

Please feel free to debate this because I am not a hunderd percent sure.

 

xander

[wheelman]

The hot exhaust gasses exitting directly from the dp will destroy the muffler. It needs to be far enough away so that the gasses cool to the point they won't burn up the packing and/or the outside of the muffler.

 

Wheelman

[Guest boosted]

THANKS guys . A couple of good reasons not to dump directly into a muffler from the DP. And they all seem like good reasons to me. I figured that there had to be a + or -

thanks again.

Kev

[Sparky]

I'm running a 3" pipe straight thru that dumps at the differential..no muffler.

 

I personally love the sound but think It might just be a little too loud for the local PD. (I have not driven the car enough to be harassed yet) once I get the car going again for daily driver duty I will reevaluate my exhaust setup and consider installing a borla bullet muffler in the stock muffler position, canting it at an angle to reduce bend radius....this is only a plan

[bjhines]

I have put a few exhaust on 240Zs.

 

It is a good idea to replace your engine and tranny mounts BEFORE you add your new exhaust...things may not line up properly when you attempt to replace them later on.

 

There are a variety of headers out there...some will require custom stud lengths..most will work with the stock studs...some will require a great deal of trimming washers to even the contact between the exhaust and intake manifolds. They are all prone to flex and breakage of the outermost studs.

 

It is a good idea to add a flex joint right after the 2-1 collector...this will take strain off the studs..but it will require extra support aft of the flex joint.

 

The factory placement of the resonator just after the collector was done to break up resonance in the long straight run to the rear. I think this is a good idea...It has been suggested that it may add some midrange power when compared to a similar exhaust without it. Whatever you decide to use..it should be a straight through design...and it should be at least 8" long and significantly wider than the rest of the exhaust tubing....similar results could be obtained by placing the resonator at the aft end of the long run( just in front of the differential)...though the forward placement will even out flow through the entire run.

 

Muffler choices are more personal...A Dynomax is a very popular muffler for Z cars. It has a sound that is similar to the stock Z-car growl...You can keep one factor in mind when making choices...A straight through design will ALWAYS be louder than a baffled chamber design.... I have heard a Z with a NA L28 with 2 straight though mufflers...one in the resonator location and one in the normal rear location...with 2.5" tubing it was LOUD!!...2 does not make it much softer than just one.

 

When deciding tubing sizes...2.5" is the most popular....3" may not maintain enough gas velocity at low RPMs to scavenge properly...It has been said that Z-cars with 3" tubing sacrifice some off the line pull...I have never compared 3" with smaller sizes on a street car...most 3" systems are on race cars that do not need the low end "street" response.

 

last item on the list.....A "resonator" exhaust tip can be very effective at damping the sound as it leaves the system...this can slightly reduce the noise.... most systems end with a short section of straight tubing... that can set up a popping resonance that actually increases the noise...

 

Make sure you beef up the factory hangar points when you replace your exhaust...most of them are held on by 2 small spot welds...they are prone to breakage.

[Guest bastaad525]

a mufflerless turbo motor being 'quiet' is a matter of oppinion

 

I ran mine both with just the open DP, and also with a pipe from the DP to where the differential is, with no muffler, and both were way too loud for my tastes. The sound of the turbo spooling is VERY cool, but still the exhaust is loud enough to draw unwanted attention, for sure... I was very afraid to get on mine anywhere but on the freeway.

[Guest boosted]

I agree. Open DP wasnt as muffled as I had expected it to be compard to an open header NA. But the throttle response and turbo response were very impressive with the open DP. Im going to have to install an exhaust cutout because once ya run open DP nothing else compares. Its like having sex without a comdom..... It feels so damb Good.

[Guest iskone]

According to a test that was done by David Vizard in one of his "How to Build Horsepower in Any Engine" books the length of exhuast tubing between a muffler and exhaust as no effect on horsepower. This was done on a NA SBC.

 

That's not to say all the reasons mentioned above (like destroying the muffler) are not good reason to put the muffler in the rear.

 

Just dump it straight out of your down pipe, hey it'll keep your feet nice and toasty!!!

 

Isk

[Guest boosted]

iskone , thanks for the tips . IProbably only the heat would effect the muffler and just the muffler life at that. exhaust fumes are beginning to bother me. I smell bad (my clothes) after a good run.

 

Dumping through just the downpipe does warm up the floor a bit .(ok since its still a little cool weather here) but since i removed the air conditioning for this build the extra heat will be unwanted soon. When i built the DP its only about 12-15" down after the 45* off the turbo . so it points to the pavment which seems to reflect the sound a bit too. Ive got a muffler here im going to cut open and see if I can tune it a bit to better suit my needs.

peace, Kevin

[Drftn280zxt]

Although I do not have a 240Z I do have a 280zx turbo. I am running three inch staight through, high flow cat, and an APEXi N-1 turbo muffler. The sound is just enough to intimidate people but not too aggresive. I has a very nice deep tone at cruising speeds that is just beautiful. As far as performance goes, on turbocharged car the freer flowing the exhuast is the better. Look at JGTC cars, most of those are turbocharged and guess what exhuast consists of headers and pipes out the back typically in the 3-4" inch range. Running a smaller diameter pipe is somewhat restrictive and thus will resonate more in the pipe/ muffler thus making it loude not to mention losing hp. The "larger the better" pipe idea is only for turbo/supercharged cars, N/A cars typically ,for performance, run 2.5" since this offers the best results in HP increases.

A very, very important thing to remember when looking at mufflers, if you are really looking for hp increases but dont what a menacing exhuast note look into straight through design mufflers nad hi-flow cats, baffler type mufflers are a BIG WASTE of MONEY, they are the most restrictive pieces of crap that exist, sorry guys who own these, but it is very true. As for muffler position, like the other guys mentioned too close and you will cook the mufflers packing if not burn holes through baffles. Putting a muffler in the middle can be benificial in one sense, you may get a nicer sound. The guy who built my mandrel bent exhuast told me that on corvettes when installing mufflers they would sound like crap with the mufflers in the back, but once they were relocated underneath the cars cabin, the exhust note was much nicer, esentially he had changed the resonating characteristics of the car to adjust the tone.

I hope this helps. Remember no baffle, just eliminate the option immediately, just because a muffler is straight does not make it ricey. Shoot my last Z sounded life a freakin race car, as in NASCAR race car, that car was an N/A 280zx with 3" crushed bent exhuast with an APEXi turbo muffler, and no catylic converter ( it was a 79, not neccessary to have a cat), I gained some power but a 2.5" inch exhuast would have been more beneficial.