STS vs Intercooled turbo and pressure drops.
05-12-2004, 07:06 PM
#1
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STS vs Intercooled turbo and pressure drops.
I grew increasingly currious so I went and did some research at work. those of you that dont know, i just started working for a company that does powertrain cooling for some caddys amongst other cars. Read a bit, talk a bit, formulate an idea.
The idea behind any radiator, trans cooler, intercooler- whatever; is to get as much cooling with as little pressure drop as possible.
Pressure drop will occur when the fluid (air or liquid) is cooled but not substantially; almost negligable. the majority of it comes from the geometry. Longer and thinner tubes provide more resitance than short fat tubes (common sense). curves, espc tight ones provide more resistance. the greater the resistance, the greater the pressure drop.
So how does this apply:
In the car, the idea is to get the MOST air in the cylinder. This is super simplified because we are not taking the momentum of air, reversion ect into account.
The intercooled version's advantage is that it cools air more and makes it denser; but that denser air is moving slower due to the fact that it has less pressure.
The STS is moving faster, but less dense.
Best way i can describe it is- think of a highway. A few cars going 120mph vs twice as many cars going 1/2 as fast. which one gets more cars across? Density vs velocity. Thats about as far as that comparison applies though.
Eventually, things begin to start leveling out. Where it is, i have no idea. Keep bumping up pressure and the heads will begin gain less and less air flow per unit of increased pressure/velocity. Still flow more but you will reach point of deminishing returns. The amount of pressure lost will also decrease as the total pressure increases- i think. someone back me up on this one.
The intercooler will be able to keep cooling the air as you pump up the boost so you will get more air through becaue its more dense. The STS will begin to fall behind as boost increases. The intercooler's larger pressure drop wont be a big deal, but because it can cool it will have much much much denser air coming in and the pressure are so high on both, it wont much matter.
An intercooled system is obviusly "better." i dont think anyone is arguing that. However, the STS might have an advantage at low boost levels because of the decreased pressure drop. Think of a s/c car with the blower off/ or at very low boost levels like 2 or 3 psi- runs like crap. Or a t/c with a big lag.
But turn it up and the intercooler will eat it up. Whats low and high? I have no idea and cant even begin to guess. Knowing the LS1 heads; it will probobly be at a higher PSI than your generic chevy 350 head.
This is based on minimal research and I havn't taken my fluids class yet so if i'm wrong, feel free to let me know
So where does this leave us? Right back where we started but I'm done pooping so I'm going to stop (God bless wireless net)
The idea behind any radiator, trans cooler, intercooler- whatever; is to get as much cooling with as little pressure drop as possible.
Pressure drop will occur when the fluid (air or liquid) is cooled but not substantially; almost negligable. the majority of it comes from the geometry. Longer and thinner tubes provide more resitance than short fat tubes (common sense). curves, espc tight ones provide more resistance. the greater the resistance, the greater the pressure drop.
So how does this apply:
In the car, the idea is to get the MOST air in the cylinder. This is super simplified because we are not taking the momentum of air, reversion ect into account.
The intercooled version's advantage is that it cools air more and makes it denser; but that denser air is moving slower due to the fact that it has less pressure.
The STS is moving faster, but less dense.
Best way i can describe it is- think of a highway. A few cars going 120mph vs twice as many cars going 1/2 as fast. which one gets more cars across? Density vs velocity. Thats about as far as that comparison applies though.
Eventually, things begin to start leveling out. Where it is, i have no idea. Keep bumping up pressure and the heads will begin gain less and less air flow per unit of increased pressure/velocity. Still flow more but you will reach point of deminishing returns. The amount of pressure lost will also decrease as the total pressure increases- i think. someone back me up on this one.
The intercooler will be able to keep cooling the air as you pump up the boost so you will get more air through becaue its more dense. The STS will begin to fall behind as boost increases. The intercooler's larger pressure drop wont be a big deal, but because it can cool it will have much much much denser air coming in and the pressure are so high on both, it wont much matter.
An intercooled system is obviusly "better." i dont think anyone is arguing that. However, the STS might have an advantage at low boost levels because of the decreased pressure drop. Think of a s/c car with the blower off/ or at very low boost levels like 2 or 3 psi- runs like crap. Or a t/c with a big lag.
But turn it up and the intercooler will eat it up. Whats low and high? I have no idea and cant even begin to guess. Knowing the LS1 heads; it will probobly be at a higher PSI than your generic chevy 350 head.
This is based on minimal research and I havn't taken my fluids class yet so if i'm wrong, feel free to let me know
So where does this leave us? Right back where we started but I'm done pooping so I'm going to stop (God bless wireless net)
05-12-2004, 08:08 PM
#2
i think i agree with some of what you are saying. asuming the intercooler isn't horiably designed i think the presure where it becomes usefull is prety low. maybe as low as 4 or 5 psi. that being said very few people will mess with boost and only run 4psi meaning an intercooler will add power to most kit's. certainly at 15psi like they are running on that sts kit a true intercooler would increase power but the alcohol injection seems to be doing a nice job of making up for it.
05-12-2004, 10:08 PM
#3
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Somehow I feel resonsible for this thread 
,
this all good to know so if i plan on running 9-10 psi then basicly I can only gain with the intercooler. thats what i was thinking, before, glad i brought it up the otherday
,this all good to know so if i plan on running 9-10 psi then basicly I can only gain with the intercooler. thats what i was thinking, before, glad i brought it up the otherday
05-12-2004, 10:28 PM
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pretty good and valid points trey. the sts kit will constantly have a problem with pressure drops. the adaptation on an intercooler will fix the problem with the help of tuning and shift patterns.
05-12-2004, 11:06 PM
#5
Originally Posted by speedhoe04
pretty good and valid points trey. the sts kit will constantly have a problem with pressure drops. the adaptation on an intercooler will fix the problem with the help of tuning and shift patterns.
05-13-2004, 12:13 AM
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well good question. first off, the turbo is not sized properly. even if you went to the upgraded version of the turbo they offer its still not sized properly especially what stall converter your running. NOW, the piping length from where the turbo sits that goes all the way to the TB is LONG. Now that doesnt mean it is going to give you lag but what it does mean the density of the pressure velocity drops the longer you go thru the piping. Now when you place an intercooler in the mix, the pressure cools down expanding the pressure therefore making the pressure denser; so now you got a cooler denser pressure velocity going to your engine vs a hotter less dense pressure velocity going to your engine.
the drop in power in the rpm level has several reasons why this happens. I can not get into it fully because these were the problems we corrected with our kits we are developing lol. however, you got to look at it this way: stall converter, tuning your shift patterns and rpm levels, turbo sizing, and your boost PSI levels are key, theres a few more reasons lol
for sts having an advantge in lower boost levels, think of it this way, you have a V8 with a smaller turbo such as the sts one....lot of ccs in the 5.3L or even the 6.0L will get that little turbo moving pretty damn fast quickly, its simple math. you will feel a 1 second pause before you get to about 2000 rpms.
turning up the boost and saying the intercooler will eat it up...not necessarily the case. you can turn up the boost and place the intercooler properly with the turbo properly and you will get efficient boost levels, you can turn the boost up with an intercooler quite high, probably even higher then a methanol based coolant, but the advantage to an intercooler is you have something with zero maintenance and its alot safer then methonal with high boost levels.
thats my gander lol
the drop in power in the rpm level has several reasons why this happens. I can not get into it fully because these were the problems we corrected with our kits we are developing lol. however, you got to look at it this way: stall converter, tuning your shift patterns and rpm levels, turbo sizing, and your boost PSI levels are key, theres a few more reasons lol
for sts having an advantge in lower boost levels, think of it this way, you have a V8 with a smaller turbo such as the sts one....lot of ccs in the 5.3L or even the 6.0L will get that little turbo moving pretty damn fast quickly, its simple math. you will feel a 1 second pause before you get to about 2000 rpms.
turning up the boost and saying the intercooler will eat it up...not necessarily the case. you can turn up the boost and place the intercooler properly with the turbo properly and you will get efficient boost levels, you can turn the boost up with an intercooler quite high, probably even higher then a methanol based coolant, but the advantage to an intercooler is you have something with zero maintenance and its alot safer then methonal with high boost levels.
thats my gander lol
05-13-2004, 12:15 AM
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two more things, "even if you went to the upgraded version of the turbo they offer its still not sized properly especially what stall converter your running." also the engine size determines the turbo size #1.
and yes the longer piping cools down the pressure charge like an intercooler, but its alot less dense, the key is getting that charge cooled fast enough to maintain the density of the pressure.
and yes the longer piping cools down the pressure charge like an intercooler, but its alot less dense, the key is getting that charge cooled fast enough to maintain the density of the pressure.
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05-13-2004, 12:46 AM
#8
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howbout this...if you were going to add an intercooler to the sts...where would u pipe it in at?
Originally Posted by speedhoe04
two more things, "even if you went to the upgraded version of the turbo they offer its still not sized properly especially what stall converter your running." also the engine size determines the turbo size #1.
and yes the longer piping cools down the pressure charge like an intercooler, but its alot less dense, the key is getting that charge cooled fast enough to maintain the density of the pressure.
and yes the longer piping cools down the pressure charge like an intercooler, but its alot less dense, the key is getting that charge cooled fast enough to maintain the density of the pressure.
05-13-2004, 01:25 AM
#10
TECH Apprentice
ETA????
Originally Posted by speedhoe04
i cant answer that, that information has to do with my design, however, in the short future i will do a presentation of my kit when it has completed.