People with dual smic, how much improvement do you get?
04-28-2004, 07:32 AM
#21
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What would you say is more efficient?
the dual smic setup with no add ons (mister or wheel vents) or a properly designed fmic? i've been going back and forth between duals or a fmic for over a month. a main reason i'm leaning towards the fmic is because i see some people get the dual setup and then feel the need to make other adjustments to get them to work better. at that point, you might be in the price range of a good fmic.
04-28-2004, 08:03 AM
#23
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Note the key phrase "properly designed" FMIC rarely has a name attached.
The duals do. They're from Audi. The duals have far more potential to be efficient than the FMIC. They have more core front surface area. They have wind tunnel tested and optimized ducting. Once the vents are added (another $80 or so plus time) the scavenging effect of the rotating tires sucks air through them at the same time it's getting rammed in the front. No radiator issues, no bumper issues, no bling issues, no lost fog-light issues, and no advertising to local cops to do a hood check.
People are adding CO2 or NOX sprayers to FMICS as well as misters. This is to get a short term cooling effect for one shot rapid acceleration in race applications. We're talking street and highway driving here.
The one advantage of the FMIC identified by Bosch is the cooling effect of the radiator fan when the car is at rest. But if the FMIC is jammed behind the bumper you have zero air flow and the both the radator and that section of the IC just getting hotter. Kind of cancels out the benefit. The DSMIC's, on the otherhand won't soak because there's zero boost and consequently much lower air temperatures at idle. Remember, the point of the IC's is to remove the heat the turbo puts in. At idle you're virtually a normally aspirated engine and NA engines don't have IC's.
Enjoy the duals. They're the best choice unless you like the look of the FMIC. That's style, not science, and style is entirely your choice.
People are adding CO2 or NOX sprayers to FMICS as well as misters. This is to get a short term cooling effect for one shot rapid acceleration in race applications. We're talking street and highway driving here.
The one advantage of the FMIC identified by Bosch is the cooling effect of the radiator fan when the car is at rest. But if the FMIC is jammed behind the bumper you have zero air flow and the both the radator and that section of the IC just getting hotter. Kind of cancels out the benefit. The DSMIC's, on the otherhand won't soak because there's zero boost and consequently much lower air temperatures at idle. Remember, the point of the IC's is to remove the heat the turbo puts in. At idle you're virtually a normally aspirated engine and NA engines don't have IC's.
Enjoy the duals. They're the best choice unless you like the look of the FMIC. That's style, not science, and style is entirely your choice.
04-28-2004, 08:13 AM
#24
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This is not really going to be settled until...
...both DLSJ5 and I strap on three calibrated thermisters to measure ambient, turbo out, and last IC out temperatures. From that we can calculate the IC efficiency (or diffusion as Bosch calls it).
Pressure loss is most likely negligible in both cases. Volume of air between the two systems is likely higher with the duals than most FMIC's so you'll see some slight (milisecond) additional lag with the dual. But keep in mind a too small FMIC won't do it's primary job of cooling - you'll just get hotter air quicker.
Doing the temperature readings will factor out volume/lag and pressure loses and focus on what IC's are all about - cooling.
Prediction: once the superiority of the DSMIC cooling setup is established the FMIC guys will scream about pressure loss. Sigh. Then I'll have to add before and after pressure gauges. Really though, Audi, Porsche, Lambo, Bosch, Hoppen and many others have already done this research a lot more thoroughly than I will ever be able to. What did they choose? Front or Side?
Pressure loss is most likely negligible in both cases. Volume of air between the two systems is likely higher with the duals than most FMIC's so you'll see some slight (milisecond) additional lag with the dual. But keep in mind a too small FMIC won't do it's primary job of cooling - you'll just get hotter air quicker.
Doing the temperature readings will factor out volume/lag and pressure loses and focus on what IC's are all about - cooling.
Prediction: once the superiority of the DSMIC cooling setup is established the FMIC guys will scream about pressure loss. Sigh. Then I'll have to add before and after pressure gauges. Really though, Audi, Porsche, Lambo, Bosch, Hoppen and many others have already done this research a lot more thoroughly than I will ever be able to. What did they choose? Front or Side?
04-28-2004, 08:14 AM
#25
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I might be wrong - but at one time someone with duals did some intake temp testing
and then compared it to the FMIC. I know of the one you are talking about - which was a Stage III setup. It's been a couple years since this was done though.
04-28-2004, 08:54 AM
#27
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Yes, that's the one, the only one, and it's defective on two counts...
1) it's clearly an SSMIC versus FMIC comparison, and
2) it's against a bigger turbo which puts out more heat.
Not honest on either count concerning the DSMIC. All it's saying is a big turbo pumping through an IC not designed for it's HP, compression, or heat output doesn't do as well as as smaller turbo on a much larger core. And from this "truth" the DSMIC is "proven" to be less efficient than a bumper blocked, radiator blocking, no ducting, lower number of long tubes, lower front surface area FMIC? Amazing!
Some of these people could make big money writing ad copy for JC Whitney.<ul><li><a href="https://forums.audiworld.com/tt/msgs/891292.phtml">This is "truth"?</a></li></ul>
2) it's against a bigger turbo which puts out more heat.
Not honest on either count concerning the DSMIC. All it's saying is a big turbo pumping through an IC not designed for it's HP, compression, or heat output doesn't do as well as as smaller turbo on a much larger core. And from this "truth" the DSMIC is "proven" to be less efficient than a bumper blocked, radiator blocking, no ducting, lower number of long tubes, lower front surface area FMIC? Amazing!
Some of these people could make big money writing ad copy for JC Whitney.
<ul><li><a href="https://forums.audiworld.com/tt/msgs/891292.phtml">This is "truth"?</a></li></ul>
04-28-2004, 09:00 AM
#28
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Summer awaits. :)
When the ambient air is cool to begin with, you won't notice much difference. The most immediate thing I noticed is I sure can hear the turbo spool up whine. I like it! Maybe Audi left out the vents so more conservative drivers (who won't need the extra IC to begin with) wouldn't be "disturbed" by the noise.
At a recent tech fest I got to see an Audi RS6 and a 225 TT up on the rack. Both had the wheel liner vents. Even the single IC 180 TT has the vents behind its IC. However, take note, these are not just holes punched into the liner. They're very deliberately arranged and grouped downward-pointing louvers. This is so the spinning wheels suck the air out through the SMIC's and rocks and dirt don't get thrown inside. Slick engineering.
At a recent tech fest I got to see an Audi RS6 and a 225 TT up on the rack. Both had the wheel liner vents. Even the single IC 180 TT has the vents behind its IC. However, take note, these are not just holes punched into the liner. They're very deliberately arranged and grouped downward-pointing louvers. This is so the spinning wheels suck the air out through the SMIC's and rocks and dirt don't get thrown inside. Slick engineering.
04-28-2004, 09:27 AM
#29
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I think the guys name was JazzTT or something like that who had the same setup as TTschwing
did but on stock duals. I'm not gonna argue that the dual is a bad setup, nor the FMIC is better in all applications - but I seem to remember that they did post numbers that showed the FMIC was better. What someone needs to do is produce a better DSMIC setup than factory. Something without plastic end tanks.
04-28-2004, 09:31 AM
#30
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Lots of guys on Vortex have added the TT "vents" to their VW's
The cut em out of the TT liner and then put it on their VW's. I also think that B5 A4's were putting S4 wheel liners on the SMIC side of their A4 with minimal modification.