TVS Failure

[Gr8snkbite]

Saw this over on SVTP......:wow2:

http://www.svtperformance.com/forums/shelby-gt500-150/798244-death-tvs-pics-plenty.html

[Alloy Dave]

Wow...that must be a manufacturing defect..wonder if he contacted Ford and got anything for it.

[Joe G]

:wow2:

[Tommy Gun]

Sometimes this type thing depends on the tuner, unless it just happens to be a manufacturing defect.


I'm glad I thoroughly trust my tuner. :grin:

.

[Birdman]

Looks like a front bearing failure. The owner drover the car 600 miles after the bearing started to make noise..dufus....:nonono:
Don't know if the bearing was hurt possibly when a pulley was installed or if it was simply a bad bearing. Either way no way he should have driven the car that far with a known problem like that.

[Gr8snkbite]

Yea, that was a Darwin award move for sure......but he should have also removed the intercooler and cleaned it properly as well.

[onecrazydog]

Sometimes this type thing depends on the tuner, unless it just happens to be a manufacturing defect.


I'm glad I thoroughly trust my tuner. :grin:

.

Who is your tuner?

[onecrazydog]

Looks like a front bearing failure. The owner drover the car 600 miles after the bearing started to make noise..dufus....:nonono:
Don't know if the bearing was hurt possibly when a pulley was installed or if it was simply a bad bearing. Either way no way he should have driven the car that far with a known problem like that.

Tough supercharger though!! Ground down but didn't snap...

[Birdman]

Who is your tuner?

same as yours...:grin:

[68fastback]

Looks like a front bearing failure. The owner drover the car 600 miles after the bearing started to make noise..dufus....:nonono:
Don't know if the bearing was hurt possibly when a pulley was installed or if it was simply a bad bearing. Either way no way he should have driven the car that far with a known problem like that.

I wonder who did the aftermarket polishing ...I bet it's really easy to contaminate a SC when polishing it if not really carefull -- just a little grit will do it.

[onecrazydog]

same as yours...:grin:

Car is running great too, no codes, no failsafes... Just like factory...

[Birdman]

Car is running great too, no codes, no failsafes... Just like factory...

Imagine that who'da thought that was possible right....:grin:

[68fastback]

:wtg: ;-)

[Birdman]

Yea, that was a Darwin award move for sure......but he should have also removed the intercooler and cleaned it properly as well.

Agreed that would of course mean having to remove the entire lower intake to get to it. For someone who seems to choose the easy way instead of the right way to do things there was no way he was going to do that I'm sure.

After all instead of at least taking the SC belt off before driving the car 600 miles with the problem (or maybe getting it towed) he decided it was easier to just drive it the way it was...:doh:

[Tommy Gun]

I guess I don't quite understand the inner workings.

If the S/C isn't spinning how does the air intake through it to run the car?

I take it there is enough void behind or around the rotors for air to pass?

[Birdman]

I guess I don't quite understand the inner workings.

If the S/C isn't spinning how does the air intake through it to run the car?

I take it there is enough void behind or around the rotors for air to pass?

I think with a TVS there might be enough air flow but I've never tried to run the engine with the belt off. I'm sure it wouldn't run too well but I believe it would run. Remember the engine itself is an air pump and doesn't need boost to run.


A twin screw like a whipple might be a different story though, it may indeed be too restrictive, dunno.


Either way that's what they make "flat bed" tow trucks for.

[Tommy Gun]

I understand the engine can pull the air in, but I don't see where it would pull it through? I thought the rotors would block the airflow if not spinning.

No biggie, just wondering.

[Birdman]

I understand the engine can pull the air in, but I don't see where it would pull it through? I thought the rotors would block the airflow if not spinning.

No biggie, just wondering.


Although I never tried it I think if the SC belt came off with a TVS SC when driving the engine would still keep running just not with the same power of course. I know it keeps running with a centrifical type SC , had that happen with the Tbird once.

[Gr8snkbite]

I understand the engine can pull the air in, but I don't see where it would pull it through? I thought the rotors would block the airflow if not spinning.

No biggie, just wondering.

Here is some light reading for you....

http://auto.howstuffworks.com/supercharger3.htm

[Tommy Gun]

Here is some light reading for you....

http://auto.howstuffworks.com/supercharger3.htm


2 things I don't understand.


One if the belt is off how air gets through the housing.

Two, why you don't always see boost when it is always spinning.

[Joe G]

Two, why you don't always see boost when it is always spinning.

I don't know the answer to your first question, but the 2nd one is due to the bypass valve. When you're not under load, it's open and there's no boost.

[Carnut]

2 things I don't understand.
One if the belt is off how air gets through the housing.
.

Just like any engine without a supercharger, except the air is sucked through the gaps in the rotors of the supercharger.

[Tommy Gun]

Just like any engine without a supercharger, except the air is sucked through the gaps in the rotors of the supercharger.

I thought they were pretty tight clearances, guess not.

[Tommy Gun]

I don't know the answer to your first question, but the 2nd one is due to the bypass valve. When you're not under load, it's open and there's no boost.


My centrifugal sways makes boost. I hear the bypass valve blow it off when it doesn't use it.

I guess the engine only uses it under certain vacuum conditions that I don't understand.

.

[Gr8snkbite]

http://www.youtube.com/watch?v=9wpatO9rcQg&feature=youtube_gdata_playerhttp://www.youtube.com/watch?v=9wpatO9rcQg&feature=youtube_gdata_player

[Joe G]

http://www.youtube.com/watch?v=9wpatO9rcQg&feature=youtube_gdata_player:goodpost:

Rep points!

[68fastback]

Q1: I'm with TG in that I don't see how the air gets by the rotors if the belt is off and *if* the rotors don't turn, except that the NA airflow may just spin the rotors anyway. Alternatively, it may not need to get by the rotors since the default-open bypass valve may then function as a default intake conduit (reverse flow) if the rotors did not spin by themselves or in the event of a jammed rotor due to catastrophic bearing failure or whatever. Dunno.

Q2: what Joe said ....bypass valve.

(that write-up is quite biassed in it's "efficiency" comment [twinscrew vs roots] since it is clearly assuming old-gen pre-TVS roots ...just sayin')

Cool vid!!

[Gr8snkbite]

At low speeds air is passed thru the bypass.....at higher speeds air passes thru the rotors( will actually spin them freely) b/c the bypass closes but mpg will suck

[Birdman]

Q1: I'm with TG in that I don't see how the air gets by the rotors if the belt is off and *if* the rotors don't turn, except that the NA airflow may just spin the rotors anyway. Alternatively, it may not need to get by the rotors since the default-open bypass valve may then function as a default intake conduit (reverse flow) if the rotors did not spin by themselves or in the event of a jammed rotor due to catastrophic bearing failure or whatever. Dunno.

Q2: what Joe said ....bypass valve.

(that write-up is quite biassed in it's "efficiency" comment [twinscrew vs roots] since it is clearly assuming old-gen pre-TVS roots ...just sayin')

Cool vid!!

I've been thinking about this question of will the engine run with the blower belt off. I have to dissagree with you on this Dan. I've had the TVS completly apart when I ported it. Air enters the rear of the blower and in between the rotors it then travels along the rotor volutes forward until it reaches a realitivly speaking small opening in the front SC case. It then will travel down and enter the intercooler then ultimately be distributed to each cylinder combustion chamber. The only difference is the air will not be compressed as it goes through the case but it's flow will be lessened .

You can see the pathway along the rotors in these pics.

http://i189.photobucket.com/albums/z234/svtbird91/Engine%20Mods/removerotorsnout.jpg

http://i189.photobucket.com/albums/z234/svtbird91/Engine%20Mods/removerotorassy.jpg

http://i189.photobucket.com/albums/z234/svtbird91/Engine%20Mods/Rotorassembly.jpg

[68fastback]

...looks like maybe it can flow down along the case sides?? ...where it normally flows ...but that would seem to require that the air can move the rotors. Doesn't look like there's anyway through in the middle where the rotors mesh (by design). It's just not clear to me with the 160* of twist (almost 1/2 a turn) whether there would be an unblocked path -- i.e. from the offset inlet to the "V" outlet ...but there may be and I'm just not seeing it.

I'll have to take your word for it George, because I honestly can't tell from the pics and it's counter-intuitive to it's fixed-displacement design ...or so it would seem. That said, the airflow should also try to freely rotate the rotors if they're not jammed and there's no belt, so it might not matter.

I guess what I'm having the most trouble with is that if air can flow from inlet to outlet freely (though possibly at a reduced rate), then how does the SC actually ever produce pressure? If it did that by relying on speed and the centriofugal mass of the air (like a centrifugal which is not linear in flow), I could see it. But it's a fixed displacement SC which features nearly perfectly linear flow to rpm -- literally 'metering' out 2.3L of air for every rotation (.575L for each of the four rotor volute cavities), so I'm kinda stuck there since I can't rationalize that with an open flow ...unless the rotors can move.

[Tommy Gun]

I guess I had a pretty good question. :popcorn:

.

[68fastback]

...good questions come cheap ...good answers are considerably more valuable :biggrin:

[Tommy Gun]

So I'm cheap? :nonono:








Don't even think about it Joe! :trouble:

[Carnut]

...looks like maybe it can flow down along the case sides?? ...where it normally flows ...but that would seem to require that the air can move the rotors. Doesn't look like there's anyway through in the middle where the rotors mesh (by design). It's just not clear to me with the 160* of twist (almost 1/2 a turn) whether there would be an unblocked path -- i.e. from the offset inlet to the "V" outlet ...but there may be and I'm just not seeing it.

I'll have to take your word for it George, because I honestly can't tell from the pics and it's counter-intuitive to it's fixed-displacement design ...or so it would seem. That said, the airflow should also try to freely rotate the rotors if they're not jammed and there's no belt, so it might not matter.

I guess what I'm having the most trouble with is that if air can flow from inlet to outlet freely (though possibly at a reduced rate), then how does the SC actually ever produce pressure? If it did that by relying on speed and the centriofugal mass of the air (like a centrifugal which is not linear in flow), I could see it. But it's a fixed displacement SC which features nearly perfectly linear flow to rpm -- literally 'metering' out 2.3L of air for every rotation (.575L for each of the four rotor volute cavities), so I'm kinda stuck there since I can't rationalize that with an open flow ...unless the rotors can move.

A couple items to think about on Question 2. The vanes on the rotors have clearance in them, if not they would chew each other up under high heat situations and to make up for dimension tolerances in manufacturering. They do not have to be touching tight to pump air.

Look at a common house fan, it moves air without any sort of physical case. If you could measure it even produces pressure.
The compressor section of turbine engine is full of blades with huge gaps between them and they produce pressure.
A turbo charger on a car and some superchargers use blades with gaps and they produce pressure.
My BDS blower on my 351 Cleveland powerd Falcon has no bypass valve, has twin rotors, and without a belt it will run, air leaks around and between the rotors. The rotors aren't turning at lower RPM, not sure when they start turning. I was able to drive it home after I lost a belt.

I am not arguing air can come from other places like a bypass valve (dunno). But since the engine is a rather large vacuum pump, it will suck whatever air can leak though, like the vanes of rotor.

[Gr8snkbite]

http://www.autozine.org/technical_school/engine/Forced_Induction_1.html

[Carnut]

:goodpost:


I guess if you want to get technical about it. :grin:

[Gr8snkbite]

Maybe it'll help Dan understand better......:giggle:

[Birdman]

http://www.autozine.org/technical_school/engine/Forced_Induction_1.html

Nice little article on the different types of forced induction.

[Tommy Gun]

A couple items to think about on Question 2. The vanes on the rotors have clearance in them, if not they would chew each other up under high heat situations and to make up for dimension tolerances in manufacturering. They do not have to be touching tight to pump air.

Look at a common house fan, it moves air without any sort of physical case. If you could measure it even produces pressure.
The compressor section of turbine engine is full of blades with huge gaps between them and they produce pressure.
A turbo charger on a car and some superchargers use blades with gaps and they produce pressure.

My BDS blower on my 351 Cleveland powerd Falcon has no bypass valve, has twin rotors, and without a belt it will run, air leaks around and between the rotors. The rotors aren't turning at lower RPM, not sure when they start turning. I was able to drive it home after I lost a belt.

I am not arguing air can come from other places like a bypass valve (dunno). But since the engine is a rather large vacuum pump, it will suck whatever air can leak though, like the vanes of rotor.



How well did it run w/ no belt?


.

[68fastback]

A couple items to think about on Question 2. The vanes on the rotors have clearance in them, if not they would chew each other up under high heat situations and to make up for dimension tolerances in manufacturering. They do not have to be touching tight to pump air.

Look at a common house fan, it moves air without any sort of physical case. If you could measure it even produces pressure.
The compressor section of turbine engine is full of blades with huge gaps between them and they produce pressure.
A turbo charger on a car and some superchargers use blades with gaps and they produce pressure.
My BDS blower on my 351 Cleveland powerd Falcon has no bypass valve, has twin rotors, and without a belt it will run, air leaks around and between the rotors. The rotors aren't turning at lower RPM, not sure when they start turning. I was able to drive it home after I lost a belt.

I am not arguing air can come from other places like a bypass valve (dunno). But since the engine is a rather large vacuum pump, it will suck whatever air can leak though, like the vanes of rotor.

Interesting, especially since I'd guess the BDS rotors likely have very little twist. Did you notice if the snout was spinning while it was runnig with no belt? That would be great to know. The BDS probably has larger gaps than the TVS, which uses a self-clearancing ablative coating (to automatically set the final gap near 'zero' at max rpm and heat), but they'd still be pretty small on the BDS too, I'd guess -- seemingly too small to pass any significant amount of air which is why I'm wondering if the rotors were spinnning with no belt on your BDS.

[Carnut]

How well did it run w/ no belt?


.

Like a low compression 351 Cleveland with too much carburetion, I limped it home as I remember.

[Carnut]

It's been several years, don't recall if they spun at all or if I even looked at the time.

[Boston Mike]

Bill, I am utterly concerned for your safety in light of this. I suggest you take off your TVS and send down for an instant inspection.



:grin:

[mustang loco]

Bill, I am utterly concerned for your safety in light of this. I suggest you take off your TVS and send down for an instant inspection.



:grin:

loll,went thru this with JD and Joe last yr...inspection ....:doh2:

[Tommy Gun]

:ohsnap: