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Old 06-08-2012, 09:48 AM   #46
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

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Originally Posted by badbug3 View Post
i I just dont understand why people would want such a big turbocharger and fight all the problems they are having with too much boost when a smaller turbo matched to the hp level desired would make more sense to me and also eliminate most if not all of the lag associated with the bandaids applied to the larger turbo. jmo
Cost is a big factor Gary.
Water jacketed custom turbo's like you have probably cost 3 times what the Borg Warner S 475's like we are using cost.
Off the shelf S 475's are only about $ 650.
Race compressor covers like I have add about another $ 225. each. I really didn't need those for what I'm doing.
Lag is not a factor at all with these turbo's Gary.
They hit too hard as it is IMO.
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Old 06-08-2012, 11:15 PM   #47
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

you want to make 2000hp on big motors you need big turbos... plain and simple..
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Old 06-09-2012, 02:45 PM   #48
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

the 42-94 garrett turbos that i have only cost about $1000 each and come with the iron turbine housing. I just chose to buy the water jacketed turbine housings to keep the heat away but are not necessary. They are good in pairs for aroung 1600-1700 hp .
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Old 06-09-2012, 07:55 PM   #49
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

what water jacketed housings are you using? the turbos we are using at the moment are 4202's..

what AR are they?? 1.40??
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Old 06-09-2012, 08:09 PM   #50
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

here is a couple of vids i did from a race the other week.. you can see the boost holding solid at 10-11psi when the foots on the floor, i have the soft springs in it at the moment as it makes it easier to drive, when i put the 20psi springs in it it is hard to hold consistant speed.. this is from the 1up bridge to bridge which is 114km, Towing 14 year old Shantelle King, she did it in 45min 30sec with a high 80mph average and the fastest female up the course on the day..

back view first 10min or so
http://www.youtube.com/watch?v=o_JV8FMuZbU

last min or so..
http://www.youtube.com/watch?v=03a6KM0HsZA
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Old 06-11-2012, 12:14 PM   #51
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

Pretty awesome vids man.
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Old 08-29-2013, 06:01 PM   #52
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

bringing this back up. want to know if anyone else is doing this with success
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Old 08-29-2013, 09:49 PM   #53
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

I put a button on the steering wheel and a solenoid to apply boost to the BOV I have controlling the boost . When its blown open it is at 12psi, when I hit the button and close the BOV the boost goes to 25psi, brings in almost 900 more hp . Works great. I have been hammering the thing all summer and it hits better than a huge shot of NOS.
Here is a vid , I launched with 12psi, let it level off , and then hit the button so everyone could see how it works.
this short pass was over 120mph
http://www.youtube.com/watch?v=51zk2kgDxSk
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Old 08-31-2013, 08:51 AM   #54
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

thanks for the info. i might try this with no wastegates at all
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Old 09-17-2013, 10:37 AM   #55
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

early testing is VERY promising

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Old 09-27-2013, 05:14 AM   #56
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

further testing, not so much
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Old 09-27-2013, 08:06 AM   #57
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

[QUOTE=RegalRocket;8894965]
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Originally Posted by tininjun67 View Post


No I don't have em confused. I've been running turbos on cars and airplanes for 15 years.



If you remove the resistance in a turbo (mass of air via flow) with the same exhaust energy, the wheel speed will spike. Its like taking a car to neutral at speed and WOT.

These are not positive displacement compressors, a total plugging of the turbo outlet will not slow the turbo down, it will cause it to shoot through the roof.



I stare at some of the most high performance centrifugal compressors every day for work. This stuff isn't theory or backyard assumptions.
Your vacuum clean comparison is correct.. BUT... When you plug a vacuums "INTAKE" , and the electric motor is still driving it's impeller.. The vacuum will speed up..

Plug the "INTAKE" on a turbo, with full exhaust energy acting on the turbine.. And the unit will instantly go into overspeed, and probably blow the turbine wheel..

Opening a BOV on the "OUTLET" side of a turbo, with full exhaust energy, will take the load off the compressor wheel.. And cause the turbo to speed up.. But not like your vacuum comparison, where you plug the intake..
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Old 09-27-2013, 10:25 AM   #58
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

People need to keep a few things in mind before jumping on the "turbo overspeed" bandwagon. Firstly, the wastegate on the headers is doing 90% of the work, it's not like you are TRYING to achieve a greater boost pressure and have a leak, the turbo shaft speed will NOT increase for the following reason:

The wastegates are already controlling most of the shaft rpm for a given boost pressure, you want to decrease this pressure so you open a valve on the charge pipe, this air escaping the valve now doesn't enter the engine, removing air that will otherwise enter the engine to drive the turbine. Saying opening a bov or gate on the cooler pipe will reduce turbo life is bollocks, there is nothing in this scenario that had happened to increase shaft rpm over the current situation.

Open her up son, cheap, simple and effective fix

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Old 09-27-2013, 11:52 AM   #59
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

Wouldn't a larger turbine be the best option? I am not taking sides on bleeding boost. I'm just sayin.
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Old 09-27-2013, 03:32 PM   #60
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Default Re: Anyone Controlling Boost Bleeding Off Boost Pressure?

[QUOTE=Bellman;12449346]
Quote:
Originally Posted by RegalRocket View Post

Your vacuum clean comparison is correct.. BUT... When you plug a vacuums "INTAKE" , and the electric motor is still driving it's impeller.. The vacuum will speed up..

Plug the "INTAKE" on a turbo, with full exhaust energy acting on the turbine.. And the unit will instantly go into overspeed, and probably blow the turbine wheel..

Opening a BOV on the "OUTLET" side of a turbo, with full exhaust energy, will take the load off the compressor wheel.. And cause the turbo to speed up.. But not like your vacuum comparison, where you plug the intake..
Your reading what I said wrong.

But any time you move more air, it always takes more energy to drive that air. More energy needed will always result in a slower wheel speeds.

Plug the outlet of a turbo and you will not be moving air and will not need energy and wheel speed will always increase. Its called a compressor stall and while the wheel aerodynamically stalls, its rotational speed skyrockets. We specifically control this effect in turbine engines by bleeding off the air via a bleed band that uncovers ports in the discharge end of the compressor.

Centrifugal compressors don't act like positive displacement. Thats why we measure the weight of air a centrifugal compresser. It doesn't matter which end you plug. Stop the movemnt of air through the compressor in any fashion and you remove resistance, wheel speed sharply then increases, sometimes to failure.

Your vacuum cleaner is the basic test bed. Go plug its outlet and see what the rpm does.

Last edited by RegalRocket; 09-27-2013 at 03:34 PM.
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