"boost saver" - silly idea or invention of the century?
06-13-2010, 10:26 PM
#1
"boost saver" - silly idea or invention of the century?
OK now that i've got you this far 
Here's an idea i had today while driving around.
Would it be possible / feasible to build a 'split' intake tract which can be selected via some kind of fast acting soleniod? The purpose of this would be to capture built boost in the intake tract and 'hold' it until it's needed again.
As i was driving around it just hit me that every time i shift the bypass valve would actuate and i'd lose all my boost momentum as i shifted between gears...
I thought it would be neat if somehow you could have a direct pipe that bypassed the intercooler and could be near-instantly switched on (via TPS or vacuum input?) and the intercooler tract could be completely sealed up (at full boost pressure) until needed again a half second or so later.
Here's an idea i had today while driving around.
Would it be possible / feasible to build a 'split' intake tract which can be selected via some kind of fast acting soleniod? The purpose of this would be to capture built boost in the intake tract and 'hold' it until it's needed again.
As i was driving around it just hit me that every time i shift the bypass valve would actuate and i'd lose all my boost momentum as i shifted between gears...
I thought it would be neat if somehow you could have a direct pipe that bypassed the intercooler and could be near-instantly switched on (via TPS or vacuum input?) and the intercooler tract could be completely sealed up (at full boost pressure) until needed again a half second or so later.
Code:
Turbo
|
|
X======[ Intercooler ]==== Throttlebody
| |
\____________________________________/
direct path
x = diverter
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06-13-2010, 10:53 PM
#4
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Location: Colorado
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Well, lets take a look at a 200WHP Miata. Thats about 20LBs of air per minute at about 10 psig give or take. I am rusty to the point of needing a Tetnus shot on this crap, but I do remember the most basic stuff hammered into my brain about a decade ago:
PV=nRT
P is pressure, V is volume, n is the amount of air, R is the universal gas constant, and T is Temperature. IN non-metric units, IIRC P is absolute pressure (which is basically what your guage says plus 14.7), V is cubic feet, n is lbs of air per minute (about 20 for a 200WHP Miata give or take), R is 10.73 and no I dont know exactly what the units are on it, and T is temp in Kelvin, which is whatever it is in F plus 460.
So lets see how much storage we need for one second of full beans air for the engine as the turbo provides it:
So, we have a 24 PSIA setup (10 PSI on the guage) for P. We have V, which is what we want to know about since it will tell us what size reservoir we need. We have n at .33LB of air (20LBs per minute divided by 60 seconds in a minute). We have R at 10.73, and we have T at 530K (l70F)
I get a volume of just under 76 cubic inches (I think). Thats a container about 4.2 inches per side. Which sounds good, but I dont know that a single second of airflow is worth it. Especially since you had to take that from some other boosted moment. Maybe it will help spool the turbo, but I doubt it.
Doing it as outlined here wher ethey fed me some units I am not sure about, I get a volume of 2.6 cubic feet needed at 10 psig to supply one second of air, which I think agrees with the other calc. http://www.gnttype.org/techarea/turbo/turboflow.html
PV=nRT
P is pressure, V is volume, n is the amount of air, R is the universal gas constant, and T is Temperature. IN non-metric units, IIRC P is absolute pressure (which is basically what your guage says plus 14.7), V is cubic feet, n is lbs of air per minute (about 20 for a 200WHP Miata give or take), R is 10.73 and no I dont know exactly what the units are on it, and T is temp in Kelvin, which is whatever it is in F plus 460.
So lets see how much storage we need for one second of full beans air for the engine as the turbo provides it:
So, we have a 24 PSIA setup (10 PSI on the guage) for P. We have V, which is what we want to know about since it will tell us what size reservoir we need. We have n at .33LB of air (20LBs per minute divided by 60 seconds in a minute). We have R at 10.73, and we have T at 530K (l70F)
I get a volume of just under 76 cubic inches (I think). Thats a container about 4.2 inches per side. Which sounds good, but I dont know that a single second of airflow is worth it. Especially since you had to take that from some other boosted moment. Maybe it will help spool the turbo, but I doubt it.
Doing it as outlined here wher ethey fed me some units I am not sure about, I get a volume of 2.6 cubic feet needed at 10 psig to supply one second of air, which I think agrees with the other calc. http://www.gnttype.org/techarea/turbo/turboflow.html
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06-13-2010, 10:59 PM
#6
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It's such a small amount of air that it wouldn't be worth capturing at all. When you're shifting gears the car isn't under load and the turbo isn't making the boost. You have like this split second of air to capture and then feed back when the car is back under load and making boost again... seems 100% pointless. Please don't think and drive.
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06-13-2010, 11:05 PM
#7
@Sparetire - I didn't take the time to do any calculations as you've so graciously done (i'm rustier than you, and it's only been 10 years), however a typical intake tract including intercooler is going to have significantly more than 76 cubic inches of air capacity no?
Assuming 2.5" diameter intake pipe length of 36", that works out to 141ci, around 2 seconds' worth of 'boost' stored in the charge pipes..
i dunno, just a thought
Assuming 2.5" diameter intake pipe length of 36", that works out to 141ci, around 2 seconds' worth of 'boost' stored in the charge pipes..
i dunno, just a thought
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06-13-2010, 11:27 PM
#14
why all the hostility? it was an idea, and i threw it out there.. i'm still not convinced it's a stupid idea, though you all seem to be!
people spend plenty of time and money on EBCs, blowoff and bypass valves, turbo blankets, new intercooler pipe routes, bar and plate vs tube & fin intercoolers, tubular manifolds, seperated gases downpipes, tuning, etc.
obviously people care about extracting the last bit of performance from their cars, so why not consider a new idea? (at least one i haven't seen tossed around).
Also i should probably clarify -- the subject of the thread was meant as a joke / to get people to read the thread... i obviously didn't htink this was the invention of the century, if that's what rankling your collective cankles
people spend plenty of time and money on EBCs, blowoff and bypass valves, turbo blankets, new intercooler pipe routes, bar and plate vs tube & fin intercoolers, tubular manifolds, seperated gases downpipes, tuning, etc.
obviously people care about extracting the last bit of performance from their cars, so why not consider a new idea? (at least one i haven't seen tossed around).
Also i should probably clarify -- the subject of the thread was meant as a joke / to get people to read the thread... i obviously didn't htink this was the invention of the century, if that's what rankling your collective cankles
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