Dynomax Ultraflo

[datsun723]

Ok so i've been doing some snooping around on the forums and i see that a lot of guys are using a variety of mufflers and pipe diameters. From what i've "learned" it seems that keeping the piping at 2.5 for a stock l28 is probably best. it seems that going to a 3in is only recommended for turbo setups and that if a 3in were to be put on a n/a l28 the lost back pressure could actually hurt the engine. so i dont want to go there.

 

anywho, i was looking at different mufflers and whatnot, and although most people go with the dynomax "turbo" muffler, you can get a considerable amount of more flow from an ultraflo.

 

my question is "is that extra flow harmful? why do many people, including Motorsports Auto, go with the "turbo" muffler?"

 

thanks-datsun723

[m4xwellmurd3r]

it's not a loss of backpressure that makes it not work as well, the volume of gas inside the tubes becomes larger than what the engine requires, which slows down the speed of the exhaust gases, which then makes the exhaust exit slower, and cool down. in a turbo Z, it's pushing out lots of hot air very fast, where the 2.5in exhaust would have a smaller area, with the engine producing a larger volume, causing an increase in pressure. increasing the pipe size maintains exhaust speed, and lowers backpressure, making it work better.

 

it's kind of like a hose. take a small hose, you get tons of pressure, and high speeds, but if you try to pump too much water through the hose, instead of getting the most water out with the lowest pressure, you're just forcing a ton of water into a pipe that doesn't want it to go out. get a bigger hose, and now you can force more water out, with a higher flow rate.

 

back pressure isn't good for an engine. but scavenging and exhaust speeds are. but at the same time bigger isn't always better.

 

i hope i don't get killed by this post >_>

 

the idea is to get the exhaust gases out of the engine as fast as you can. to do that you need a properly sized exhaust system.

[datsun723]

Makes sense to meeeeeeeeeeeeeeeeeee!

 

but i'm still confused as to why people choose the turbo muffler over the higher flowing one >_<

 

Any input oh highly exalted people of hybridZ???

[ShaggyZ]

Do some Googling and read this, too - http://auto.howstuffworks.com/muffler5.htm

[Clifton]

but i'm still confused as to why people choose the turbo muffler over the higher flowing one >_<

 

 

Because they don't know any better. People run Flowmaster and ride Harleys too:sad:.

 

I would only run a straight through muffler. Dynomax ultraflow, Magnaflow, or Hooker maxflow. There are a few comparisons of mufflers on the net and one Turbo mag did 12+ years ago. Straight through ones come out on top, Chambered (baffled) Flowdisaster on the bottom.

[X64v]

Because they don't know any better. People run Flowmaster and ride Harleys too:sad:.

 

 

 

The Dynomax turbo muffler is most definitely not a straight through. It'll be quite a bit quieter than a straight through muffler, which doesn't matter much on a turbo motor, but is important on an N/A. A straight through muffler on an N/A motor will definitely be loud (perhaps so much as to be illegal, which may be why MSA uses the turbo muffler in their kits).

[datsun723]

Do some Googling and read this, too - http://auto.howstuffworks.com/muffler5.htm

 

 

thanks shaggyz. useful information indeed. i do find it quite interesting how different dynomax mufflers are compared to say, the flowmaster 40 series. the fm seems to have all these plates and chambers inside, generating a distinct sound i suppose. the great thing about dynomax is that it has wayyyy better flow(almost 4 times the CFM) than the fm or magnaflow. since the dynomax is just a straight perforated tube lined with fiberglass, it doesn't have to go in and out of plates and chambers.

 

and the only difference i can find between the turbo and the ultraflo is that the turbo muffler has an "S" like flow for a more mellow sound while the ultraflo is just a straight shot out the back

[datsun723]

 

 

The Dynomax turbo muffler is most definitely not a straight through. It'll be quite a bit quieter than a straight through muffler, which doesn't matter much on a turbo motor, but is important on an N/A. A straight through muffler on an N/A motor will definitely be loud (perhaps so much as to be illegal, which may be why MSA uses the turbo muffler in their kits).

 

 

I came to the same conclusion. And hey, the louder the better right

[datsun723]

Because they don't know any better. People run Flowmaster and ride Harleys too:sad:.

 

I would only run a straight through muffler. Dynomax ultraflow, Magnaflow, or Hooker maxflow. There are a few comparisons of mufflers on the net and one Turbo mag did 12+ years ago. Straight through ones come out on top, Chambered (baffled) Flowdisaster on the bottom.

 

Yea, why people get the chambered ones still...baffles me:lmao:haha

 

if i could, i'd just run a straight pipe out the back but unfortunately i live in socal =/

 

i was also wondering...how's that 7mgte swap working out for you? I used to have an '88 turbo and man did i love that engine

[m4xwellmurd3r]

in my case I'm going to go with the MSA twice pipe setup and 3 to 2 headers (modifying them to be true twice pipes) i'm going with their smaller setup (i belive they do have a sizing option) and though twice pipes don't seem to be the best ideas (you lose the scavaging of 6 cylinders per pipe, to 3 cylinders per pipe.) I'm also going to try and improve the airflow through the engine. twice pipes will be the last "upgrade" on my super stock build (stock head stock block, untouched besides a rebuild, and try to get THE MOST power out of it, n/a by adding things like megasquirt, aftermarket intake mani, adjustable pressure regulator, lighter flywheel and damper, etc)

 

I'm glad I actually posted something that was helpful for a change! and it was something I actually new stuffs about! haha

[datsun723]

i LOVE the sound of twice pipes! too bad the kit msa sells doesn't include room for a cat. i HATE freakin emissions in Cali. kinda wish i had gotten a '74 260 haha.

[m4xwellmurd3r]

i LOVE the sound of twice pipes! too bad the kit msa sells doesn't include room for a cat. i HATE freakin emissions in Cali. kinda wish i had gotten a '74 260 haha.

eh you could figure something out. but that's why I love arizona (but hate arizona because it's not excempt) my car was a non-catalyst Z. it has a resonator, but no cat

[datsun723]

eh you could figure something out. but that's why I love arizona (but hate arizona because it's not excempt) my car was a non-catalyst Z. it has a resonator, but no cat

 

 

yea i could....but it's cheaper to just go with a regular setup. and i know, my first Z was a '77 from chicago so it had nothing on it but a muffler sounded nice indeed!!

[Clifton]

eh you could figure something out. but that's why I love arizona (but hate arizona because it's not excempt) my car was a non-catalyst Z. it has a resonator, but no cat

 

If you have classic/collectable insurance and the Z isn't your only car, you can register it as a collectable and not go thorugh emmsions. That's waht I did.

 

Like X64v said. A straight through might me a little loud on n/a. I run a regular dynomax glass pack (drilled, not louvered) for a resonator and a straight through mufler at the back too. I don't know if they even stop people in Az for noise, plenty of obnoctious of straight piped HD's around here.

 

I think 1 fast Z runs a Borla straight through w/ 3" on his n/a car, It didn't seem too loud.

[ktm]

I would only run a straight through muffler. Dynomax ultraflow, Magnaflow, or Hooker maxflow.

 

I would like to add Borla XR-1 to that list as well.

[ktm]

if i could, i'd just run a straight pipe out the back but unfortunately i live in socal =/

 

You have a 1978 280z. You aren't (legally) going to be able to do any swaps.

 

I am running a 3" downpipe to a 3" exhaust, no cat, no resonator, through a Borla XR-1 straight through muffler. Sounds great and is not obnoxiously loud. However, I am running a turbo as well.

[datsun723]

You have a 1978 280z. You aren't (legally) going to be able to do any swaps.

 

I am running a 3" downpipe to a 3" exhaust, no cat, no resonator, through a Borla XR-1 straight through muffler. Sounds great and is not obnoxiously loud. However, I am running a turbo as well.

 

wha wha wait?! say what!? i can't even swap in a l28et?! cuz there go my plans down the drain

[ktm]

The problem is that 1978 vehicles are not exempt from the bi-annual smog testing. The bi-annual smog test includes a visual component.

[Tony D]

wha wha wait?! say what!? i can't even swap in a l28et?! cuz there go my plans down the drain

 

YES, you CAN swap in an L28ET. Search the CA DMV and SMog websites, it's a very straightforward and easy swap. I know people who have put L28ET's into MAXIMAS and gotten the BAR sticker for their door so it's all legal.

 

Your car WILL be required to have a Catalyst, but nobody says it has to be the stock one. AFTER the catalyst (using the stock L28ET downpipe and front exhaust section) you can run whatever you want. Put a nice new high-flow 3" Catalyst in there, with the 3" exhaust back from there, and you will have a nice starting point with no problems passing smog. AFTER the cat, you are free to do about what you want.

 

But between the turbo and the cat (which everyone here knows would benefit from the 3" downpipe---20HP on a stock L28ET) you run the risk of a 'visual fail' from a non-CARB approved item IN the emissions system.

 

If you want it Legal, you will be saddled with the stock cast iron downpipe and stock pipe between there and the catalyst.

 

That all being said, if you 'upgrade it' in between tests... as long as that catalyst stays on there, most roadside inspections will not likely know to tag you on it! And after that initial referee inspection, likely it will never come up again as long as you have a functioning catalyst, and a working O2 sensor.

 

Under Cal Emissions it's pretty easy to retrofit vehicles with newer engines, most of the griping out there is done by people ignorant of the process who see a simple smog test as some insurmountable obstacle. As long as all the stock stuff is there and functioning, it passes.

[ktm]

YES, you CAN swap in an L28ET. Search the CA DMV and SMog websites, it's a very straightforward and easy swap. I know people who have put L28ET's into MAXIMAS and gotten the BAR sticker for their door so it's all legal.

 

Under Cal Emissions it's pretty easy to retrofit vehicles with newer engines, most of the griping out there is done by people ignorant of the process who see a simple smog test as some insurmountable obstacle. As long as all the stock stuff is there and functioning, it passes.

 

Tony is correct. However, the car needs to have all of the stock emissions and fuel equipment that came with the L28ET. That means no Pallet fuel rail, no aftermarket fuel pressure regulator (unless it has a CARB sticker), EGR, stock turbo intake manifold, AFM, charcoal canister, stock downpipe, etc.

 

I was simplifying the issue because most folks simply swap the engine. Hell, even my swap is illegal and I am taking a gamble (and know this) but I have a 1972 and am exempt from the bi-annual testing. However, if stopped by the police and inspected, I can be sent to to be inspected.