Compound turbo build and other updates

That is a good summary. Even re-routing the secondary air through the IC alone would put that compressor at a better spot on the map. Effectively that charger sees more motor.
 
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Those sir, are some laggy primary's. I thought my HT4B would be laggy, but it rather responsive. I've got about 4psi at 10psi total boost.
 
Those borg chargers have clipped turbine wheels too so they're gonna be ultra slow to respond.


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12vCumminsFTW said:
Primaries move the gauge at like 30 psi overall. 5 psi at 40 overall.


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Like I said before I'd sure like to see a vid of yours similar to this vid of WOP's triples where you can see boost and drive vs rpm.

[ame="http://www.youtube.com/watch?v=x_R3ZPRn0U4"]http://www.youtube.com/watch?v=x_R3ZPRn0U4[/ame]


I noticed back in the day when they came out with that set how much the primary's lagged the secondary and found it interesting as final boost still made for a nice curve rather than that ballistic hit like my 50% split does.

Look at how high final boost is before the primary's are getting kicked in the ass on WOP's set that every one was cooing about having great response which in reality is mostly because Pius likes very small secondary compressor's, I don't know the specs on that set but would not be surprised if it was 58-60mm or less.

Most would look at that primary response and say damn that's laggy.

Some more to think about any ways.
 
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Joesixpack said:
Like I said before I'd sure like to see a vid of yours similar to this vid of WOP's triples where you can see boost and drive vs rpm.

http://www.youtube.com/watch?v=x_R3ZPRn0U4


I noticed back in the day when they came out with that set how much the primary's lagged the secondary and found it interesting as final boost still made for a nice curve rather than that ballistic hit like my 50% split does.

Look at how high final boost is before the primary's are getting kicked in the ass on WOP's set that every one was cooing about having great response which in reality is mostly because Pius likes very small secondary compressor's, I don't know the specs on that set but would not be surprised if it was 58-60mm or less.

Most would look at that primary response and say damn that's laggy.

Some more to think about any ways.
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I'll get vid sometime when I get a chance. Mine acts about like that CR though. Except my secondary doesn't come on as quick. I really don't mind the primaries lagging a bit. The old s488 I had took a bit to light too, nothing like the ht4b mentioned above. If I could get more airflow off the bottom and lower cruising egts/ smoke I'd be happy. Wish someone knew the actual specs on the WOP chargers, guess it's secret squirrel stuff though.


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This is data from an old setup so I don't remember if this is from a boost launch or rolling into it, but gives you something to compare to. Same primaries as you are running but has a Super B special as a secondary. Also on a commonrail so kind of apples to oranges.
 

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Haven't been able to get a vid yet as the rear diff shelled out. Think I'm gonna try going smaller on the secondary and keep the interstage cooler first though.


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Joesixpack said:
... great response which in reality is mostly because Pius likes very small secondary compressor's, I don't know the specs on that set but would not be surprised if it was 58-60mm or less.
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Wouldn't that be the advantage of inter-stage cooling? The intercooler effectively makes the secondary seem larger to the primary, allowing for a smaller, quicker responding secondary compressor. Similar to your prior post.
 
This is an example of a compound on a 12L engine with a S480SX in combination with a Garrett GT5533r 91mm inducer hi pressure. Funny things with this set-up is that botch turbochargers are hi pressure models and the S480SX is only used for lowend spool-up from the starting line and the wastegate is only set to 1Bar or 14.5PSI so a load of exhaust gas goes to the bigger GTr turbo keeping up with boost same as the smaller S480SX.
We had to run the Garrett GT5533r with hi pressure to keep it in the flowmap and @ 2000Rpm we where running the GT5533r off the chard with 92K Rpm so we instated a second wastegate before the GT553r turbo to get the boost down while going up in RPM and maintain the same turbo speed.
Both stages have aftercoolers.

EGT is also interesting. 920 degrees centigrade into the first turbo and 640 degrees centigrade into the secondary turbo indicating that there is a lot of expansion of the exhaust gasses so chance is there is a fair bit of power transferred into boost pressure on the S480SX.
@ 2400RPM the engine makes 1442Hp and the ECU controls the turbo speed of the GT5533r with the second wastegate.

Foto540-BJ7WWTH3.jpg

Foto540-FKTXIOOU.jpg
 
tall boy said:
This is an example of a compound on a 12L engine with a S480SX in combination with a Garrett GT5533r 91mm inducer hi pressure. Funny things with this set-up is that botch turbochargers are hi pressure models and the S480SX is only used for lowend spool-up from the starting line and the wastegate is only set to 1Bar or 14.5PSI so a load of exhaust gas goes to the bigger GTr turbo keeping up with boost same as the smaller S480SX.
We had to run the Garrett GT5533r with hi pressure to keep it in the flowmap and @ 2000Rpm we where running the GT5533r off the chard with 92K Rpm so we instated a second wastegate before the GT553r turbo to get the boost down while going up in RPM and maintain the same turbo speed.
Both stages have aftercoolers.

EGT is also interesting. 920 degrees centigrade into the first turbo and 640 degrees centigrade into the secondary turbo indicating that there is a lot of expansion of the exhaust gasses so chance is there is a fair bit of power transferred into boost pressure on the S480SX.
@ 2400RPM the engine makes 1442Hp and the ECU controls the turbo speed of the GT5533r with the second wastegate.

Foto540-BJ7WWTH3.jpg

Foto540-FKTXIOOU.jpg
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Why size the chargers so close together, especially with that much displacement? Is 1400hp all you're looking for?
 
Wop triples also used small turbines roughly s258 over a s300 65 turbine nothing larger.
The last set i saw was like a 57mm over two 65mm compressors but turbine were smallest for that frame of turbo. As stated earlier the 68mm turbines would flow 60lbs/min and single gt55 1.0 housing is 59lbs/min. So with the 73 turbines you are up in the 70lbs/min range.
 
kjpcummins said:
Wop triples also used small turbines roughly s258 over a s300 65 turbine nothing larger.
The last set i saw was like a 57mm over two 65mm compressors but turbine were smallest for that frame of turbo. As stated earlier the 68mm turbines would flow 60lbs/min and single gt55 1.0 housing is 59lbs/min. So with the 73 turbines you are up in the 70lbs/min range.
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Interesting. I wonder how much flow/efficiency these setups lose with the hotpipe being basically a T. Or is that even an issue.
 
madmikeismad said:
Why size the chargers so close together, especially with that much displacement? Is 1400hp all you're looking for?
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I would have used a 95mm or even 98mm inducer size on the secondary compressor to get some more RPM out of this engine. They came from 1200Hp @ 2200Rpm and calculated 1500Hp max, Fuel system per stroke is maxed out so 1442Hp is max @2400RPm but they have some more homework to get it all on the track as during testing they get 0,7sec of there 80 meter time but unable to perform this during the last dragrace event and only get 0,3sec faster than all previous runs. The way I look @ things is get data and make improvements and make the next step work. It’s not al about Hp but what works best.:blahblah1:
 
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