Seriously looking into compounds... Need help tho
- Thread starter Noonman350
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Morgan@Midwest Diesel & Auto
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I would assume you would not have a compound turbo engine that can't handle compounds. When you don't want the boost you pull pw. It's pretty simple you just don't push it if it can't handle it.
Just pull fuel till you feel safe. If you have too much fuel pushing the compounds, then dumping drive pressure is a poor way of controlling it. Your only gonna relieve the extra fuel by dumping it into the downpipe, why not just pull fuel out of it?
For the op like I said the dual waste gates is not necessary for lower power, daily driving or towing. He isn't gonna have enough fuel to need them anyway.
If your BP is too high then you could add them later but it probably won't happen.
Morgan@Midwest Diesel & Auto
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Fwiw I know people running 400/200 with a non waste gated s475 and have nearly 1:1 boost to BP ratios with a 1.1 housing and the 83/89 turbine. So why would you need to waste gate around a 88/96 135 s488 in a compound? I see no BP issues with that. If your boost is too high you'll just be running cleaner.
65psi of clean running 7.3 ftw!
65psi of clean running 7.3 ftw!
Morgan@Midwest Diesel & Auto
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I think that with some custom tunes and a ts you could be able to turn it down for DD or towing. Them turn it up for play time (which is when mine always breaks)!
Noonman350
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Ok so... I will only need to waste gate the HP turbo then? Or should I still hate both of them. And would I run it into the down pipe?
silverpsd_06
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I wish I could find a link to Charles thread on psn when he was building his compound set.. Would answer alot of your questions.. Personally I would do two gates. I don't think pulling pw would really solve the problem for the atmosphere charger running to high a pressure
This one has some fantastic info in it, mostly theory stuff though.
http://powerstrokenation.com/forums/showthread.php?t=91269&highlight=return
http://powerstrokenation.com/forums/showthread.php?t=91269&highlight=return
Powerstroke Cowboy
Well-known member
What about wanting a fast spooling set up... But keep the boost low because you dont have fire rings... BUT still want to have as much power as the injectors will give you??
I would gate both stages. If you never use the one stage o well. it is easyer to do as you build the setup then go in later and try and do it..
Lets say the OP is looking for a max of 55 psi on the gauge @ the intake manifold, So he runs his 38R @ just 15psi. (that would require a gate) and to keep the boost at or below 55 psi he only needs to see 26 PSI on the gauge (figuring we are @ see level) Would he not need a gate to keep it there if he wants to use all the fuel from the injectors?? Now if he is looking for 50 psi max then he would need to see about 21psi from the atmosphere on the gauge.. To keep the Atmosphere there without a gate would require either no trying to use any where close to all the fuel the 250/200 has.. OR run such a big Exhaust housing that the turbo spools so late in the game that you have to pull fuel back in the mid-range to keep it from smoking...
The math was a just toss together quick deal might not be 100% correct. Remember I was talking gauge PSI..
Feed me in what I am missing?? I still say gates on both are a good thing.. It just deepends on what your goals are..
I would gate both stages. If you never use the one stage o well. it is easyer to do as you build the setup then go in later and try and do it..
Lets say the OP is looking for a max of 55 psi on the gauge @ the intake manifold, So he runs his 38R @ just 15psi. (that would require a gate) and to keep the boost at or below 55 psi he only needs to see 26 PSI on the gauge (figuring we are @ see level) Would he not need a gate to keep it there if he wants to use all the fuel from the injectors?? Now if he is looking for 50 psi max then he would need to see about 21psi from the atmosphere on the gauge.. To keep the Atmosphere there without a gate would require either no trying to use any where close to all the fuel the 250/200 has.. OR run such a big Exhaust housing that the turbo spools so late in the game that you have to pull fuel back in the mid-range to keep it from smoking...
The math was a just toss together quick deal might not be 100% correct. Remember I was talking gauge PSI..
Feed me in what I am missing?? I still say gates on both are a good thing.. It just deepends on what your goals are..
Blowby
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What about wanting a fast spooling set up... But keep the boost low because you dont have fire rings... BUT still want to have as much power as the injectors will give you??
I would gate both stages. If you never use the one stage o well. it is easyer to do as you build the setup then go in later and try and do it..
Lets say the OP is looking for a max of 55 psi on the gauge @ the intake manifold, So he runs his 38R @ just 15psi. (that would require a gate) and to keep the boost at or below 55 psi he only needs to see 26 PSI (19.80 psi) on the gauge (figuring we are @ see level) Would he not need a gate to keep it there if he wants to use all the fuel from the injectors?? Now if he is looking for 50 psi max then he would need to see about 21psi (17.32 psi) from the atmosphere on the gauge.. To keep the Atmosphere there without a gate would require either no trying to use any where close to all the fuel the 250/200 has.. OR run such a big Exhaust housing that the turbo spools so late in the game that you have to pull fuel back in the mid-range to keep it from smoking...
The math was a just toss together quick deal might not be 100% correct. Remember I was talking gauge PSI..
Feed me in what I am missing?? I still say gates on both are a good thing.. It just deepends on what your goals are..
Changed a few numbers to meet your goal. Gate both turbos so you can control the psi on each turbo.
Powerstroke Cowboy
Well-known member
Care to share what math equation you used to get the new numbers? Or just explain what you did?? This part has always got me.. I have had others tell me different then what you must use...
silverpsd_06
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Let me take a whack at the equation its been a while since i have done this...
Basically you are wanting an psig reading of 55psi which is actually 69.7psia (take into account the 14.7 atmospheric pressure) and you are wanting the second stage loafing along at a 15psig or 29.7psia divide all of those numbers by 14.7 to get your pressure ratios..
Looks something like this.
x = 69.7/ 29.7 you are trying to figure out your first stage pressure ratio or
X= 4.74/2.0 which will leave you with a pressure ratio on the first stage of approximately 2.36.
Take 2.37x 14.7 which gives you 36.92psia
Now 36.92- 14.7 for atmospheric pressure to get your psig reading will leave you just shy of 20psig out of the atmospheric turbo..
To turn that around to figure for total psig reading at the manifold it would be. 2.36x 2.0 = 4.72
4.74x 14.7 = 69.67psia
69.67-14.7 = 54.97psig
Some of that may be a little off but you get the idea of the formula of how to figure it.
Basically you are wanting an psig reading of 55psi which is actually 69.7psia (take into account the 14.7 atmospheric pressure) and you are wanting the second stage loafing along at a 15psig or 29.7psia divide all of those numbers by 14.7 to get your pressure ratios..
Looks something like this.
x = 69.7/ 29.7 you are trying to figure out your first stage pressure ratio or
X= 4.74/2.0 which will leave you with a pressure ratio on the first stage of approximately 2.36.
Take 2.37x 14.7 which gives you 36.92psia
Now 36.92- 14.7 for atmospheric pressure to get your psig reading will leave you just shy of 20psig out of the atmospheric turbo..
To turn that around to figure for total psig reading at the manifold it would be. 2.36x 2.0 = 4.72
4.74x 14.7 = 69.67psia
69.67-14.7 = 54.97psig
Some of that may be a little off but you get the idea of the formula of how to figure it.
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lincolnlocker
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op, sorry for the hijack...
is the waste gate on a 38r that comes stock on it to small to utilize in a compound setup if the housing was cross drilled? even if still using smaller injectors and just wanted to clean up the fuel it has and be snappy off idle with instant throttle response? im debating between compounds as long as i can keep the A/C or going to a pro-charger, but i want to have it reliable as possible... not to many pro charged 7.3s out there to ask about reliability on cross country trips. i travel a lot in a years time...
is the waste gate on a 38r that comes stock on it to small to utilize in a compound setup if the housing was cross drilled? even if still using smaller injectors and just wanted to clean up the fuel it has and be snappy off idle with instant throttle response? im debating between compounds as long as i can keep the A/C or going to a pro-charger, but i want to have it reliable as possible... not to many pro charged 7.3s out there to ask about reliability on cross country trips. i travel a lot in a years time...
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silverpsd_06
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Exceptionally small..I wouldn't recommend that to my worst enemy you can keep the a/c its just tougher and i would recommend a 1" body lift to make things a little easier on ya under the hood
silverpsd_06
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http://powerstrokearmy.com/forums/showthread.php?t=10848
Here is the link to my compounds.. Little rough looking and need some finishing touches put on them but they worked pretty well for what they are
Here is the link to my compounds.. Little rough looking and need some finishing touches put on them but they worked pretty well for what they are
silverpsd_06
New member
To build a little bit on what you are going after with compounds lets take a look at some compressor maps...
This is for a 38r.. same turbo as the op is wanting to utilize as his secondary charger
j
This is the turbo that Charles has used in his compound setup that worked very well for him.
Now if you can imagine lay those compressor maps over one another the peak efficiency for both just kind of runs together and it looks like one big long compressor map. This is the main reason 90 percent of people tell everyone asking about compounds to start with something in the 88mil inducer range, granted a borg warner will not act exactly like a garrett but it will be close performance wise.
Now look at the compressor map for the 4294.. You are really not gaining much over the 38r. To me nothing is really to be gained until you get into the 88mm range over just having a 70-75mm single that is responsive and flows a good 90-95lbs/min.
This is for a 38r.. same turbo as the op is wanting to utilize as his secondary charger
This is the turbo that Charles has used in his compound setup that worked very well for him.
Now if you can imagine lay those compressor maps over one another the peak efficiency for both just kind of runs together and it looks like one big long compressor map. This is the main reason 90 percent of people tell everyone asking about compounds to start with something in the 88mil inducer range, granted a borg warner will not act exactly like a garrett but it will be close performance wise.
Now look at the compressor map for the 4294.. You are really not gaining much over the 38r. To me nothing is really to be gained until you get into the 88mm range over just having a 70-75mm single that is responsive and flows a good 90-95lbs/min.
bad12jr
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This thread has some great info. Still thinking about throwing a set on the SD but really wanna fire ring it first.
Just out of curiosity how would a van charger with a ported housing and say a 38r ww2 hold up as the HP?
Sent from my x2 chillin in the middle of no where
Just out of curiosity how would a van charger with a ported housing and say a 38r ww2 hold up as the HP?
Sent from my x2 chillin in the middle of no where
Powerstroke Cowboy
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silverpsd_06
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There are guys that have done that its all in how you gate it to make the HP turbo live. I know there was a guy back on psn who built a set out of a stocker and a s480 made like 450ish horsepower. So it can be done but your backpressure had better be in check. Depends on what you're wanting to do. Daily drive and tow you may be able to get away for a long time. David lott built a set for someone with a s480 atmosphere.
