Turbo Compressor Maps - Effect of Ported Shrouds and "The Tornado"

The intake plumbing is short and straight, no MAF either. Look at the picture that is straight into the tornado. You can see the inside of the K&N cone filter. The filter is about a foot long.

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I'm lost with this especially with a 60-1 compressor wheel. I would start at the beginning by not using that tornado.My friends car with a Ta62 wasn't surging or acting stange at part throttle. I don't see why you need a tornado at this point.
 
TTipe said:
I'm lost with this especially with a 60-1 compressor wheel. I would start at the beginning by not using that tornado.My friends car with a Ta62 wasn't surging or acting stange at part throttle. I don't see why you need a tornado at this point.

The 62 uses a larger turbine and the shaft speed is going to be lower for a longer time. So the pressure ratio vs throttle angle at light throttle will be less.
 
I may try it sometime without the tornado. Easy enough to just get a short piece of pipe to replace the one with the tornado stuck in it.

A little more info on the turbo: bolt on bell, Garrett .60 cold side housing, AiResearch .63 hot side housing. No idea of the wheels, never had it apart.

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If thats Bruce's old turbo, it may be the one he got from me. 60-1 compressor, dynamic seal. 69 trim turbine.

Bob
 
If thats Bruce's old turbo, it may be the one he got from me. 60-1 compressor, dynamic seal. 69 trim turbine.

Bob
If it had a .60 a/r garrett compressor hsg and a .63 a/r garrett turbine hsg then it was a Ta61.
 
Not sure if the turbo came from you (Bob) or not. As for which one, then TA61 it is. Raining today so no driving, but I'm going to try it without the Tornado in the near future.

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RmvBfrFlght said:
Not sure if the turbo came from you (Bob) or not. As for which one, then TA61 it is. Raining today so no driving, but I'm going to try it without the Tornado in the near future.

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TA equals stock compressor cover. 61 equals garrett small shaft 60-1 compressor and 69 trim turbine usually. Same as PT 54. The names are made up and don't mean much.
 
TTipe - Just to clarify, *all* of the flow through the exhaust is highly turbulent. We're talking about a gaseous mixture moving at high speed, high pressure, and high temperature... very high Reynolds number and thus quite turbulent. Cylindrical pipe flow goes turbulent at Re ~ (o) 1000, and these flow numbers are likely (o) 100,000.

The sensor is likely introducing some slight restrictions in the exhaust flow, but I'm really not sure that it's a first-order effect. Bison's experience shows that it's not significant. It's also probably subject to lots of other factors, so the results would vary from car to car.

mgmshar - Thanks for an interesting read. Makes sense to me that a fixed "tornado" device wouldn't likely result in significant gains across the entire range of operating conditions, but may have benefits under certain applications (part throttle, etc). I appreciate the discussion.
Jon-stop by again.Great discussion and an opportunity to learn.I thought the discussion was on general turbo efficiency concepts and places to look for more efficiency.Moving the o2 is not a big hitter in my mind,but may be the result of controls combination(low hanging fruit).I am extremely pleased with my turbo (TA61) but it has a lot of work in it.
 
Jon-stop by again.Great discussion and an opportunity to learn.I thought the discussion was on general turbo efficiency concepts and places to look for more efficiency.Moving the o2 is not a big hitter in my mind,but may be the result of controls combination(low hanging fruit).I am extremely pleased with my turbo (TA61) but it has a lot of work in it.


I disagree about the O2 idea.
I tried it [apparently I wasn't the first] and loved it.
Park a GVM74 in the DP ]from the mid 90's Impala cop cars] and watch the faster spoolup.
The thing that disturbs me is that people have sectioned their headers,cleaned up the ends of the tubes and loved the improvement, but pull that lump of an O2 away from the inlet of the turbo and some would say you're nuts.
Oh well.;)

BTW,watch out for the chopsticks.
 
I disagree about the O2 idea.
I tried it [apparently I wasn't the first] and loved it.
Park a GVM74 in the DP ]from the mid 90's Impala cop cars] and watch the faster spoolup.
The thing that disturbs me is that people have sectioned their headers,cleaned up the ends of the tubes and loved the improvement, but pull that lump of an O2 away from the inlet of the turbo and some would say you're nuts.
Oh well.;)

BTW,watch out for the chopsticks.
I don't have seatbelts in the back so the "Elders" are stuck at the hotel.There is a take out Thai food joint nearby.
 
Doing a bit of work on the Black Car today so snapped a pic or two. This is looking into the end from the turbo side. Appears to be a 3" unit cut down to fit a 2-3/4" pipe. Blade angle is 12*. Blades are rather long, but didn't measure the length.

This is in front of a TA62 with a few inches between it and the inlet bell. My understanding is that part throttle boost was undriveable without it.

View attachment 167577View attachment 167578

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Going all the way back to the OP, the VIGV's were tested at angles of 60, 70, and 80 degrees. The Tornado has a blade angle of 12 degrees. Big difference. I would summize from the results in the OP that VIGV's with 12-degree angle would move the surge line just a little to the left and cause only a small drop in compressor efficiency and max flow. I am just assuming that based on what happens when going from the 80 to 70 to 60-degree VIGV results.

This helps me understand why those who are running Tornados don't see huge losses in compressor performance (i.e. little difference at the drag strip running high boost). Interesting that the relatively small 12-degree blade angle moves the surge line enough to keep the compressor out of surge at part throttle.

Thanks for posting the pics and measurements.
 
> Going all the way back to the OP, the VIGV's were tested at angles of 60, 70, and 80 degrees.
> The Tornado has a blade angle of 12 degrees. Big difference.

Figure that 80* is almost perpendicular to the airflow, that is going to be quite a restriction.

Drove the car today without the Tornado. Went with as high as 15 psi and varying between that and 0 psi with no surging. I'll soon be pushing more boost as it is still being tuned (boost & tune in increments).

It may be that more boost is required for it to surge. Or, that it may not surge at all. A lot has changed on this car over the years which may have also changed the induction characteristics.

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Going all the way back to the OP, the VIGV's were tested at angles of 60, 70, and 80 degrees. The Tornado has a blade angle of 12 degrees. Big difference. I would summize from the results in the OP that VIGV's with 12-degree angle would move the surge line just a little to the left and cause only a small drop in compressor efficiency and max flow. I am just assuming that based on what happens when going from the 80 to 70 to 60-degree VIGV results.

This helps me understand why those who are running Tornados don't see huge losses in compressor performance (i.e. little difference at the drag strip running high boost). Interesting that the relatively small 12-degree blade angle moves the surge line enough to keep the compressor out of surge at part throttle.

Thanks for posting the pics and measurements.


That's always been one thing I didn't like about the Tornado solution.
I often wondered if the vanes in those couldn't be *straightened up a bit* without damaging it to reduce any inlet air scrubbing caused by the straight air rubbing against the angles?
 
>...Drove the car today without the Tornado. Went with as high as 15 psi and varying between that and 0 psi with no surging. I'll soon be pushing more boost as it is still being tuned (boost & tune in increments).

It may be that more boost is required for it to surge. Or, that it may not surge at all. A lot has changed on this car over the years which may have also changed the induction characteristics.

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No matter how much max, or part throttle boost I run ie: factory boost control vs rjc style, if I leave the alky off, it never surges, with alky it surges. Makes sense since the "juice" makes the compressor more efficient. If I had better heads and a free flowing exhaust housing, the surge would probably go away even with alky if I stayed with this turbo; but who does that... Running it without alky, as I do in the winter, it'll surge some, again from the efficient air, but never in 50 degrees and above w/out alky. Simple engine theory; it can't eat more than it poops. Every car is unique in detail but this theory applies to all of them. The tornado slows down the eating a bit to get the whole combo back in line. Should everyone have a tornado? No. But those of us that use them and need them will show no loss at the strip even if running it all out. The exhaust will always be the restriction; in mine and similar setups.
 
No matter how much max, or part throttle boost I run ie: factory boost control vs rjc style, if I leave the alky off, it never surges, with alky it surges. Makes sense since the "juice" makes the compressor more efficient. If I had better heads and a free flowing exhaust housing, the surge would probably go away even with alky if I stayed with this turbo; but who does that... Running it without alky, as I do in the winter, it'll surge some, again from the efficient air, but never in 50 degrees and above w/out alky. Simple engine theory; it can't eat more than it poops. Every car is unique in detail but this theory applies to all of them. The tornado slows down the eating a bit to get the whole combo back in line. Should everyone have a tornado? No. But those of us that use them and need them will show no loss at the strip even if running it all out. The exhaust will always be the restriction; in mine and similar setups.

Very interesting. At this time with the tuning I'm doing, the alky is off. And the spark timing is low along with the weather being hot (about 85* F ambient). Which all fits into when your set up doesn't surge.

As for spool up time, not a double blind study, but I felt as though it did spool a smidge quicker.

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Very interesting. At this time with the tuning I'm doing, the alky is off. And the spark timing is low along with the weather being hot (about 85* F ambient). Which all fits into when your set up doesn't surge.

As for spool up time, not a double blind study, but I felt as though it did spool a smidge quicker.

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I run less initial alky than Julio sends the kit set at but I do turn mine on at 5psi instead of 8psi and that causes surge right around 11-14psi. Very minor though with tornado but car will buck without it and surge boost window widens. Spool seems similar with and without alky to my butt however the RJC controller makes the part throttle boost come up quick when maxx is set to 25psi+. I've never tried my current setup without alky and using race gas. That would probably require timing adjustments to make it work right. On another note, the surge got better with new valve springs and cam and my theory is that the engine was simply able to move more of the incoming air efficiently at part throttle, all else being equal.
 
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