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That same inside look, those louvers, create a standing wave effect, which blocks flow. On the dyno, it cost us over 50 hp loss. We put a straight pipe on and got back our 50 hp.
I guess the best test is dyno before and after. That is where the proof is.

Sorry, no info on the Aeroturbine.

Our testing was done on a Nissan VG30, 3 Liter, 4-Cam, 24 valve, Single ceramic ball-bearing turbo engine (ya I know, patooie).
To make it street legal in AZ, the fuzz wants to see a muffler. Depending on where you "Garage" the vehicle, you don't need a cat. (AZ is off road car friendly if you know how to play the system).

We first used a "Turbo Muffler" from Autozone, and that was a total joke. It wouldn't make more than 2 Lbs of boost.
Next was a straight pipe after the turbo, and instant 8K RPM's, 20+ PSI of boost. YEeeee HAwwwwww!!!
Then someone recommended we try a "Cherry Bomb" style. I'm here to tell ya, if I didn't see it, I wouldn't believe it.
All we did was stick it on the end of the pipe, you can see straight through it, and it killed the boost. That motor cried and balled. Hardly any boost. Take the "Straight Through" Cherry Bomb off, instant fun again. Now I ask "Why."

Next up was the Flowmaster with it's "Sound Cancelling Technology." The 70 series we used has two chambers, a few strategically placed pieces of what looked like angle iron, no fiberglass packing to blow out. On it went and the fun continued. So that became standard. If it works, don't fix it.

All the rocket scientists I discussed this with claim that the exhaust is spinning when it comes out of the turbine. It’s believed that those louvers will cause the turbulent air flow to start packing up instead of letting it through. That's the theory anyway.
This story is so you can be wise to this. Try the straight pipe first and base your performance results on that. Then put the muffler on and if you lose, then you know how to get it back.

So would you expect a Magnaflow to be comparable to a Flowmaster/straight pipe or one of the crappy mufflers?

Quote:

So would you expect a Magnaflow to be comparable to a Flowmaster/straight pipe or one of the crappy mufflers?

I’ve never seen inside a Magnaflow, or have I tested one on a car on the dyno. I don’t know. I will say if there is one around the next time we do a test, “Let’s find Out!”

Two different kinds of engines here. Diesel’s are WFO, or Wide $#%# Open all the time (no throttle plate). Gassers (ya I know, Patoie) are part throttle most of the time, only when WFO are they sort of comparable (exhaust temps, exhaust speed because of compression ratio difference, etc.).

One way to look at this: The reason a 2 liter turbo gasser acts like a 4 liter engine (at 15 PSI of boost), is because it is now displacing 4 liters of air.

Without a lot of bench racing and talking, the best way to find out it to just go try it. Maybe for all the wrong reasons, some things just work out.

By the way, we are not making 30 PSI of boost. I have seen 15 and under on my CRD.
I think some might be mixing absolute or KPA’s with Gauge pressure. The MAP reports absolute. My tire gauge tells me I have 30 PSI in the tires, but a MAP would say there is 45. This is because it starts at –1 atmosphere.

The Magnaflow stainless "cat back" system that people put on our CRDs are actually for the V-6 gas version. (There is no diesel version.) I can attest to the internal dimension of the muffler being the same size as the pipe all the way through, but I was not aware of the existence of different muffler designs for diesels.

DOC

When hard on the loud pedal, my Dipricol Boost guage will hit 30psig rat real quick-like - which would be ~45psia on the scantool - I got air...............

Author:	RTStabler51 [ Sat Jul 11, 2009 6:21 pm ]
Post subject:	MBRP Exhaust
Installed the MBRP SS Exhaust today. Very straight forward installation. The part that took me the longest was getting the stock on out because I spent about 30 minutes trying to get it out in one piece. I finally succumbed and busted out the hack saw. Boxed End w/ Part Number for the SS Version Packaged very well. No parts rattling around. The two exhausts layed out next to one another. Tail Pipe Camparo. The MBRP does have a bit more of a higher bend. To get this part on, I had to move my jack stand to the body to lower the axle and 'open up' the coil spring and work the exhaust hanger through the spring. Looking down the stock muffler and its 'choke' point. Looking down the MBRP muffler Here is a video. Its really not that much louder than stock, not even sure in this video you can tell a difference. On the road, its just a tick louder than the original exhaust. Is it worth the ~$350? Depends on what you want. I think it is, as I didn't want to hack the muffler out and figuring that out. For a catback system, I thought the price was awesome. Fitment was great. The only thing I was leary about was the exhaust hangers weren't 'snug' on the MBRP exhaust and it 'wiggles' around a bit more than the stock exhaust did. On my 30 minute drive after installing, I didn't hear any rattles of the exhaust hitting anything, so I am happy with it. Bottom line, I recommend this. And its easy to install in your drive way. From start to finish, to include a run to the parts store for more hack saw blades, approximately 2hrs.

Author:	gmctd [ Sat Jul 11, 2009 8:05 pm ]
Post subject:
Izzat a optible collusion, or is that MBRP choke-point just as bad as the original? Muffler id should be same as pipe, straight thru, inlet to outlet - that one appears to be more for the gasser (patooie!) versions, which to them wouldn't matter, long as it's shiny...................

Author:	RTStabler51 [ Sat Jul 11, 2009 8:17 pm ]
Post subject:
I didn't get out the measuring stick, but the ID is about the same as the same as the cat outlet ID.

Author:	gmctd [ Sat Jul 11, 2009 11:54 pm ]
Post subject:
I'm still seeing a neckdown just inside that flared flange, then a second neckdown just B4 the diffuser upsets in the main pipe - those are the silencers - woulda helped if the muff had been up off the cement so the backlite would illuminate the details - anyway, post how that works out fer ya, economy-wise - losing that oem restriction should net a little better fuel mileage - now.....who's gonna crawl up under there and keep it polished fer ya?

Author:	Turbo Tim [ Sun Jul 12, 2009 12:32 am ]
Post subject:
That same inside look, those louvers, create a standing wave effect, which blocks flow. On the dyno, it cost us over 50 hp loss. We put a straight pipe on and got back our 50 hp. Next we put a Flowmaster on, no loss on hp. (Flowmasters have baffles in compartments, no louvers). This was on an off road car, turbo'ed. If it works ok on a CRD, then the only thing that might be happening is that the length of the pipe is much longer before the muffler than on the off road cars. I know the argument that "I can see right through it," but remember that the exhaust is spinning like a tornado, not a laminar flow, yet. I guess the best test is dyno before and after. That is where the proof is.

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MBRP Exhaust http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=44951	Page 1 of 2

Author:	CRD Joe [ Sun Jul 12, 2009 1:03 am ]
Post subject:
With respect guys, mufflers aren't necessary with our turbo charged engines! None of my four diesel trucks (4.2 liter Toyota land cruiser, 2.4 liter samurai, 1.9 liter Jetta and 2.8 liter KJ have mufflers. Why restrict what dosent need to be restricted?

Author:	KJ 119 [ Sun Jul 12, 2009 1:22 am ]
Post subject:
That stainless sure is perty. Turbo Tim wrote: That same inside look, those louvers, create a standing wave effect, which blocks flow. On the dyno, it cost us over 50 hp loss. We put a straight pipe on and got back our 50 hp. I guess the best test is dyno before and after. That is where the proof is. Wow Tim,thats some big numbers. What's yor take on the Aeroturbine?Any dyno testing or info? Bub

Author:	Turbo Tim [ Sun Jul 12, 2009 12:07 pm ]
Post subject:
Sorry, no info on the Aeroturbine. Our testing was done on a Nissan VG30, 3 Liter, 4-Cam, 24 valve, Single ceramic ball-bearing turbo engine (ya I know, patooie). To make it street legal in AZ, the fuzz wants to see a muffler. Depending on where you "Garage" the vehicle, you don't need a cat. (AZ is off road car friendly if you know how to play the system). We first used a "Turbo Muffler" from Autozone, and that was a total joke. It wouldn't make more than 2 Lbs of boost. Next was a straight pipe after the turbo, and instant 8K RPM's, 20+ PSI of boost. YEeeee HAwwwwww!!! Then someone recommended we try a "Cherry Bomb" style. I'm here to tell ya, if I didn't see it, I wouldn't believe it. All we did was stick it on the end of the pipe, you can see straight through it, and it killed the boost. That motor cried and balled. Hardly any boost. Take the "Straight Through" Cherry Bomb off, instant fun again. Now I ask "Why." Next up was the Flowmaster with it's "Sound Cancelling Technology." The 70 series we used has two chambers, a few strategically placed pieces of what looked like angle iron, no fiberglass packing to blow out. On it went and the fun continued. So that became standard. If it works, don't fix it. All the rocket scientists I discussed this with claim that the exhaust is spinning when it comes out of the turbine. It’s believed that those louvers will cause the turbulent air flow to start packing up instead of letting it through. That's the theory anyway. This story is so you can be wise to this. Try the straight pipe first and base your performance results on that. Then put the muffler on and if you lose, then you know how to get it back.

Author:	stoutdog [ Sun Jul 12, 2009 12:53 pm ]
Post subject:
Turbo Tim wrote: Sorry, no info on the Aeroturbine. Our testing was done on a Nissan VG30, 3 Liter, 4-Cam, 24 valve, Single ceramic ball-bearing turbo engine (ya I know, patooie). To make it street legal in AZ, the fuzz wants to see a muffler. Depending on where you "Garage" the vehicle, you don't need a cat. (AZ is off road car friendly if you know how to play the system). We first used a "Turbo Muffler" from Autozone, and that was a total joke. It wouldn't make more than 2 Lbs of boost. Next was a straight pipe after the turbo, and instant 8K RPM's, 20+ PSI of boost. YEeeee HAwwwwww!!! Then someone recommended we try a "Cherry Bomb" style. I'm here to tell ya, if I didn't see it, I wouldn't believe it. All we did was stick it on the end of the pipe, you can see straight through it, and it killed the boost. That motor cried and balled. Hardly any boost. Take the "Straight Through" Cherry Bomb off, instant fun again. Now I ask "Why." Next up was the Flowmaster with it's "Sound Cancelling Technology." The 70 series we used has two chambers, a few strategically placed pieces of what looked like angle iron, no fiberglass packing to blow out. On it went and the fun continued. So that became standard. If it works, don't fix it. All the rocket scientists I discussed this with claim that the exhaust is spinning when it comes out of the turbine. It’s believed that those louvers will cause the turbulent air flow to start packing up instead of letting it through. That's the theory anyway. This story is so you can be wise to this. Try the straight pipe first and base your performance results on that. Then put the muffler on and if you lose, then you know how to get it back. So would you expect a Magnaflow to be comparable to a Flowmaster/straight pipe or one of the crappy mufflers?

Author:	gmctd [ Sun Jul 12, 2009 1:18 pm ]
Post subject:
Ok - but, #1, we're not dealing with an 8000rpm engine - we can get and maintain 120000 turbine-shaft rpm and 30psi Boost at 1500rpm, depending on crankshaft loading, and #2, the turbine effluent is spinning, but soon as it hits the wall of the turbine outlet elbow, which acts as a diffuser, the flow begins to lose the swirl, reducing even further thru the twists and turns of the exhaust piping, with the id walls reducing that swirl even more - unless the muffler is 1' from the turbine, as there is little swirl back near the rear axle, even with absolutely straight pipe - the larger the straight pipe id, the more residual swirl, due to surface effect on laminar flow #2 - there are two technologies used in mufflers for Diesel engines and mufflers for those other engines: Diesels get non-reversing mufflers, where the flow enters the muffler into a perforated pipe to a baffled chamber at the inlet end, sidesteps into a second perforated pipe thru to a second baffled chamber in the middle, sidesteps into a 3rd perforated pipe and out - some do 2 transfers, some 3 those other engines get reversing mufflers, where the flow enters the muffler toward a baffled chamber at the outlet end, reverses flow into a 2nd pipe to a baffled chamber at the inlet end, reverses flow into a 3rd pipe and out - most do 3 inversions, but some do 4 So, what's my point? Hell, I don't know - I'm still reeling with the rest of the world over the death of the king of poop....er...pop No, wait, I remember - most aftermarket mufflers are designed for low to medium flowrates from n\a engines - flowrates from turbo'ed engines are way higher than n\a engines of the same displacement, so those mufflers you chose would have been restrictive in your application, as they are intended to reduce the peak sonic vibrations in exhaust flow, slightly reducing the perceived noise of the combustion explosion

Author:	Turbo Tim [ Sun Jul 12, 2009 2:35 pm ]
Post subject:
Quote: So would you expect a Magnaflow to be comparable to a Flowmaster/straight pipe or one of the crappy mufflers? I’ve never seen inside a Magnaflow, or have I tested one on a car on the dyno. I don’t know. I will say if there is one around the next time we do a test, “Let’s find Out!” Two different kinds of engines here. Diesel’s are WFO, or Wide $#%# Open all the time (no throttle plate). Gassers (ya I know, Patoie) are part throttle most of the time, only when WFO are they sort of comparable (exhaust temps, exhaust speed because of compression ratio difference, etc.). One way to look at this: The reason a 2 liter turbo gasser acts like a 4 liter engine (at 15 PSI of boost), is because it is now displacing 4 liters of air. Without a lot of bench racing and talking, the best way to find out it to just go try it. Maybe for all the wrong reasons, some things just work out. By the way, we are not making 30 PSI of boost. I have seen 15 and under on my CRD. I think some might be mixing absolute or KPA’s with Gauge pressure. The MAP reports absolute. My tire gauge tells me I have 30 PSI in the tires, but a MAP would say there is 45. This is because it starts at –1 atmosphere.

Author:	gmctd [ Sun Jul 12, 2009 4:02 pm ]
Post subject:
When hard on the loud pedal, my Dipricol Boost guage will hit 30psig rat real quick-like - which would be ~45psia on the scantool - I got air...............

Author:	chrispitude [ Sun Jul 12, 2009 5:14 pm ]
Post subject:
15psi gauge/30psi absolute is typical for gassers. I thought diesel's typically ran closer to 30psi gauge/45psi absolute, but I don't know where my CRD ran. - Chris

Author:	stoutdog [ Sun Jul 12, 2009 6:35 pm ]
Post subject:
Turbo Tim wrote: Quote: So would you expect a Magnaflow to be comparable to a Flowmaster/straight pipe or one of the crappy mufflers? I’ve never seen inside a Magnaflow, or have I tested one on a car on the dyno. I don’t know. I will say if there is one around the next time we do a test, “Let’s find Out!” Two different kinds of engines here. Diesel’s are WFO, or Wide $#%# Open all the time (no throttle plate). Gassers (ya I know, Patoie) are part throttle most of the time, only when WFO are they sort of comparable (exhaust temps, exhaust speed because of compression ratio difference, etc.). One way to look at this: The reason a 2 liter turbo gasser acts like a 4 liter engine (at 15 PSI of boost), is because it is now displacing 4 liters of air. Without a lot of bench racing and talking, the best way to find out it to just go try it. Maybe for all the wrong reasons, some things just work out. By the way, we are not making 30 PSI of boost. I have seen 15 and under on my CRD. I think some might be mixing absolute or KPA’s with Gauge pressure. The MAP reports absolute. My tire gauge tells me I have 30 PSI in the tires, but a MAP would say there is 45. This is because it starts at –1 atmosphere. Tim, take a look.

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Author:	DOC4444 [ Sun Jul 12, 2009 7:24 pm ]
Post subject:
The Magnaflow stainless "cat back" system that people put on our CRDs are actually for the V-6 gas version. (There is no diesel version.) I can attest to the internal dimension of the muffler being the same size as the pipe all the way through, but I was not aware of the existence of different muffler designs for diesels. DOC

Author:	gmctd [ Sun Jul 12, 2009 8:17 pm ]
Post subject:
That's a muffler suitable for a turboDiesel engine, where the turbine smooths out most of the peak noise - they can be run without a muffler in some states, require one in other states - that is likely to be changing, soon

Author:	stoutdog [ Sun Jul 12, 2009 8:25 pm ]
Post subject:
DOC4444 wrote: The Magnaflow stainless "cat back" system that people put on our CRDs are actually for the V-6 gas version. (There is no diesel version.) I can attest to the internal dimension of the muffler being the same size as the pipe all the way through, but I was not aware of the existence of different muffler designs for diesels. DOC There aren't, that is just a generic Magnaflow cutaway.

Author:	DOC4444 [ Sun Jul 12, 2009 8:38 pm ]
Post subject:
I was referring to GMCTD's post enlightening us about reversing and non-reversing muffler designs. DOC

Author:	Turbo Tim [ Mon Jul 13, 2009 12:26 am ]
Post subject:
If the pass-through is the same size as the pipe, and there are just perforations, NO Louvers, then I think it should work just fine. I still don't like the packing idea, but that's just me.

Author:	05infernoCRDL [ Mon Jul 13, 2009 12:58 am ]
Post subject:
gmctd wrote: When hard on the loud pedal, my Dipricol Boost guage will hit 30psig rat real quick-like - which would be ~45psia on the scantool - I got air............... highest i have seen is 25 on my boost guage... but i still have the VW bug under my truck for a muffler