Opinions on Ported Shrouds

I keep hearing this restriction aspect of the Tornado, not the fact that it changes the airs motion in the inlet pipe. Ok so if it does cause a restriction, then how come those with stock Maf's still have compressor surge during part throttle?? I had surge regardless of stock maf or Z06 maf and there is I believe a 2-3 psi difference ( Mike Licht had the numbers ). BTW, I have a TA49, not much smaller other than the stock turbo.

IMO, the ported shroud was a waste of $$ and I'll take the top end back with the bigger/regular cover and put a $40 Tornado in it.

I was the 2nd guy to try Bruce's findings of the Tornado years ago and it's worked on both of my turbo cars and a friends. I don't care about what perception parts have on internet boards especially when a guy like Bruce Plecan says he's tested it ( has the data ) and says it works, guess what, he's right.

And pretty soon I'm going to have a way to improve the compressor map so if it does chop some of the top end off, I'll have found a way to get it back and then some. :biggrin:
 
So has anyone actually done any accurate track testing with and without this Tornado?

Can someone please post a picture of the type used on the TRs.
 
LUCKY1313 said:
If the Tornado pushed the turbo up to a more eff part of the map it would surge more because there would be more air.


If your going to run a Tornado, you would be just as well off with a smaller turbo.

Jess
Click to expand...

Efficiency (and surge) is dependent on the flow and pressure ratio (p2/p1). At the lower flow, but with a higher pressure ratio, you are in a more efficient area of the map.... thus, out of the surge area.... even if this area is not commonly published in the distributed maps...

The second statement is just plain false....
 
Wow! That thing would certainly create some turbulent flow. Not sure but, isn't turbulent flow more restrictive?
 
DonWG said:
Wow! That thing would certainly create some turbulent flow. Not sure but, isn't turbulent flow more restrictive?
Click to expand...

Thats a good observation. Don't know if 'restrictive' is the best choice of words, but it certainly won't be laminar, will it? :smile: Actually, I think that in some cases, turbulent flow is less 'restrictive', as it doesn't 'stick' or conform to the surfaces surrounding the flow path. Your observation causes me to wonder if, in fact, the turbulence/random flow ocillations resulting from the tornado would serve to 'dampen', if you will, the surge resultant from operating the turbo in that flow region... :confused:
 
bmackinnon said:
Thats a good observation. Don't know if 'restrictive' is the best choice of words, but it certainly won't be laminar, will it? :smile: Actually, I think that in some cases, turbulent flow is less 'restrictive', as it doesn't 'stick' or conform to the surfaces surrounding the flow path. Your observation causes me to wonder if, in fact, the turbulence/random flow ocillations resulting from the tornado would serve to 'dampen', if you will, the surge resultant from operating the turbo in that flow region... :confused:
Click to expand...

The way I understand flow through a tube, or better, an intake port, you want turbulence close to the walls of the port, but not turbulence throughout the whole cross section of the port. That's why head porters recommend that the intake port walls be left rough. Some even put small concave dimples along the port walls to simulate the surface of a golf ball.

Creating turbulence is a good way to disrupt a bad flow pattern and cause it to straighten out. Like the spiraling flow that exits an exhaust turbine housing. Changing the spiraling flow to a straight flow will provide a less restrictive flow. You want to do this early on in the tube. It sounds like you're doing the exact opposite with this Tornado. Waiting 'till the end of the tube to change a straight flow to a turbulent flow. Wouldn't a tube that started out with straight flow and ended with straight flow end up flowing more than one that started with straight flow and ended with turbulent flow?
 
Yes, the tornado definitely offers up some restriction in the inlet path... I guess restrictive IS a perfectly apt word here... ;) I was just thinking aloud about how maybe disrupting that smooth flow thru the inlet would possibly mask the surge. Probably more likely that the restriction from the tornado is simply moving the operating point on the map. FWIW, I have a stock turbo and no tornado :biggrin: . I just happened to follow Bruce's thread on this, and found it quiet interesting. Especially since most who try it seem very pleased with the result. Bruce was a neat dude....
 
Tornado

Since none of us street race ,why not run tornado on the street, take it off at the track? Reading posts ,opinions seem to be 50-50 as to effectiveness. If it cures surge on street, TAKE IT OFF AT THE TRACK.
 
A few weeks back I went back to a semi stock setup and tune while i drove the car from MI to FL. Today I put my 4inch FT pipe back on with a tornado inside.

Ive had the tornado with the 4 inch back in mich and noticed a big improvment, for the move i went back to stock maf and 3inch pipe and had surge, but averaged 25mpg for the drive but anyway....so today once again i put my 4inch and tornado back and walla.. no surge or so minimal i didnt even raise half an eyebrow.

Like most changes in life I always ask myself "is it a plecebo effect" like when ya change the oil or add air in the tires and you swear the cars is faster..lol

Anyway it helps me out a great deal.
A note on the fullthrottle built in maf, I added a screen in front and that helped out the built in maf sensor to read the incomming air better...or so it seems:rolleyes:

not to hyjack the initial question but i thought id let ya know..it works for "my application"<---key word

Mike
 
I work in the hydro power industry as a machinist, we build monster water wheels.American Hydro Corporation : Home Let me just say that whether it's air or water doesn't matter, same principle. All hydro turbine dams have a "tornado" type deflector in them called stay vanes, or if they are adjustable they are called wicket gates, these are super close to the rotating turbine or runner as we call them. The purpose of these wicket gates or stay vanes is to get the water flowing in the correct direction/angle, before hitting the turbine blade entrance edge. I believe the Tornado does not reduce the flow more then a few %, the fins are thin after all, I believe it just lets the turbo spin with less turbulence because it sets the air up before it enters the turbo. I run one and was very skeptical(still have the reciept to take it back) but after my 1st test drive after installing it I now have my 5-15 psi boost range back, before this range was unuseable. Been running it for 4 months approx. car is much nicer on the street, it's not half throttle or wide open any more with nothing in between.

Chuck
 
+1 With 84BuickGN, think of it as better aerodynamics for your turbo. I highly doubt this works mainly due to the restriction aspect as I noticed ZERO loss of psi when I installed it VS when you throw on a different MAF etc. If it is a restriction, it's not enough to bother worrying about and it sure the hell isn't 15hp worth like the PS covers if those claims are accurate.

At the end of the day it works, and if you've been around these cars long enough, appreciate that and move on to issue #95. :frown:
 
Hey now, it's not really for you track guys who go WOT for only 8 seconds. :eek:

It's really a solution for us street guys who'd like to use the 7-15psi portion of our turbo's. ;)

Ted I'd also bet the TSO/TSM guys don't use the PS Cover?
 
Correct me if I'm wrong, but for that device to lessen surge, it would have to change the p2/p1 ratio relative to airflow. I would have to think that it lessens the p2/p1 ratio. It certainly would not increase it, because that would put you further into the surge range.

Or, for that device to lessen surge, it would have to change the airflow relative to the p2/p1 ratio. If it lessened airflow relative to p2/p1, it would put the turbo further into surge. The only way the device could reduce surge, as far as airflow is concerned, would be if the device increases airflow relative to p2/p1. Now I find that possibility impossible.

So that leaves the device changing the p2/p1 ratio relative to airflow. In other words, the device causes the turbo to create less boost relative to the airflow level. So you've artificially created a compressor wheel, housing combination that creates less boost relative to airflow than it would without the device. Hmmm. Wouldn't using a smaller turbo be the same thing, or maybe a larger a/r turbine housing?
 
GNVYUS 1 said:
Hey now, it's not really for you track guys who go WOT for only 8 seconds. :eek:

It's really a solution for us street guys who'd like to use the 7-15psi portion of our turbo's. ;)

Ted I'd also bet the TSO/TSM guys don't use the PS Cover?
Click to expand...

The GT 47/88 is a port shroud cover, the GT 42/76 is a port shroud cover. The record holder in TSL is running port shroud and I believe the record holder in TSO is running one also.

I wonder how they would do at 7-15 PSI. :eek: ;) :biggrin:
 
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