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Discussion Starter #1
Let's discuss intercooling! Yeah, I'm going to go there again. Specifically, I wanted to go through some calcs that I made recently to determine the best possible A2A intercooler core dimensions and see if A2A is worth it. After looking around, I feel confident that I can put together a nice A2A system for less than $1000. Look forward to hearing input from you all.

Here's my math to get us to our desired info. If you all see errors, feel free to chime in and correct me.

S62 N.A. Flow Rate
(CID*RPM*.5*Ev)/1728
=(301.5*6900*.5*.85)/1728 = 511 CFM

Pressure Ratio
(14.7+9psi)/14.7 = 1.62

S62 F.I. Flow Rate
pressure ratio * N.A. Flow Rate = 511*1.61 = 823 CFM


INTERCOOLER SIZING

Internal Flow Area Required
40in^2 internal flow area required (I snagged this number from the attached handy flow rate/flow area graph)

Area of Charge Face
(Internal Flow Area)/.45 45% of charge face available for entry into air tubes
(40in^2)/.45 = 89in^2

Charge Air Width (3" core)
(89in^2)/3in = 30 inches

Charge Air Width (3.5" core)
(89in^2)/3.5in = 25 inches

The most ideal charge face size for an A2A intercooler ranges dimensionally, but if we were to limit core thickness to 3"-3.5" then we can get away with an intercooler that is 25"-30" long. Keep in mind that this requires charge air going from top to bottom and not side to side like a lot of crappy intercoolers on the market.

Here's a nice unit in this range…
TRV25 Series Intercooler 1000HP- TREADSTONE PERFORMANCE

INTERCOOLER EFFICIENCY
In a separate thread, Vortech V3 discharge temps were discussed and tested. Vortech sets discharge temps at 190F and testing confirmed this. A2A intercoolers tend to reside in the 60-70% efficiency range. A2W range anywhere from 75-95% efficient.

Max Temp Decrease (from an intercooler)
Discharge temp - Atmospheric Temp = 190F-75F = 115F

Temp Decrease (60% Efficient Intercooler)
115F*.6 = 70F


AIR DENSITY
w/o Intercooler = 190F and 1.62 boost pressure ratio
w/ Intercooler = (190F-70F) = 120F and 1.62-1.14=1.48 boost pressure ratio ***1.14 is our assumed intercooler pressure drop of 2psi

Non-Intercooled Air Density
(297K/361K)*1.62 = 1.33 times non-supercharged air density (532HP)

A2A Intercooled Air Density (60% efficient w/2psi pressure drop)
(297K/322K)*1.48 = 1.36 times non-supercharged air density (544HP)

A2W Intercooled Air Density (80% efficient w/2psi pressure drop)
(297K/309K)*1.48 = 1.42 times non-supercharged air density (568 HP)


CONCLUSION
If all these calculations are correct and fairly conservative, which they seem to be, it seems that A2A intercoolers will produce marginal performance gains with levels of boost 9psi and lower. Though I am willing to bet that fuel economy will be significantly better, accompanied by lower coolant/oil temps. Your thoughts?
 

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You don't really need the calculations. An air to air intercooler that has decent flow will definitely reduce the charge air temps. I would not expect dramatic performance gains given the relatively low level of boost but it will give you more margin and delay or eliminate spark retard related to charge air temps. You will lose some amount of boost but it should not be too much if you choose a decent intercooler. I doubt you will see material gains in fuel economy or lower oil temps (in street driving).

The downsides are more complexity and cost, but the positives should out weight the negatives, which is why most form so forced induction have some sort of intecooler.
 

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Love the fact you are taking a shot at this.

How will the A2A be affected by the meth injection people are running. Will the benefits be minimized since the injection is also doing the job of getting rid of heat?

Or is this simply an alternative to injection?

Regards,
Jerry
 

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Not another methanol thread :eek:

Methanol is a great thing to add to or substitute for an intercooler.

A few things to keep in mind about methanol that aren't arguable (but I am sure will be argued a little further down the page hiha )

- Methanol injection not only provides a cooling effect but it ADDS fuel, it just does
- You generally don't want to inject methanol BEFORE an intercooler or the atomization you just worked so hard to achieve can be completely undone (you don't want the methanol apor cooled down and shoved through a narrow passage)
 

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Discussion Starter #5 (Edited)
Agreed, in a system like this, one would probably need to move the jet(s) to the post-intercooler charge pipe. But yeah, let's not start another methanol discussion here.

Don't get too excited about this system cause it's not happening until January at the soonest as I'm way too busy right now. Maybe Silent will jump on it though!
 

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Discussion Starter #7
Take a look at the charge air face calcs and you'll find required total charge face area. Considering that there's roughly a 6" high by 30" long lower grill opening that's maybe 3-3.5" deep, it is absolutely necessary to use a thicker core.

In addition to that, there are two different critical points for surface area, charge face and ambient face. Calculating all of these variables is important because we want to maximize efficiency and reduce pressure drop. Bigger ambient faces and larger than necessary charge pipes do not equal performance in my experience.
 

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Jamie from RK (tacoma330i) should weigh in here, as he did a fair amount of research--including multiple A2A intercooler configurations--before arriving at the RK design.

--Peter
 

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You don't need to refill an A2A IC, and it doesn't heat soak.
 

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Discussion Starter #10
Lol. Indeed. The intercooler flame war has been initiated.
 

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Calcs seem right at a glance, would be better to use the mass of air as can make it all a bit cleaner, but I get where you're coming from...

One thing to keep in mind is that the RK setup is using more outlet pressure from the SC'r to overcome the bit of pressure drop we have in the intercooler. So the 9psi outlet pressure from the SC'r isn't quite right in practice...

In our testing I was able to show boost at 9.5-10psi and temps at about 25F over ambient (ambient was 85F), for 25 laps straight... I turned meth on for the next session and was able to get to about 90F. Keep in mind meth/water needs a hot intake temp to vaporize, so if the intercooler is working, meth could be redundant and just make a pool in the pipe...

We did 3 different intercooler designs, one horizontal (pretty typical design) and 2 horizontal. Even if the surface area is the same, the one with the longer path will cool a bit more and have more pressure drop. We went with a design with less pressure drop to not have to work the SC'r so much...

If the point was to discredit that A2A intercoolers weren't worth it, that's fine. For some they're not. For those that track their car or want consistent performance from their SC'r kit, works great, without the hassles of methanol and you can count on the cooling, so you can tune for it.

Each method (A2A, A2W, Methanol) is appropriate depending on the application and user's need.

Anyone interested in discussing more, feel free to get a hold of me...
 

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Agreed, in a system like this, one would probably need to move the jet(s) to the post-intercooler charge pipe. But yeah, let's not start another methanol discussion here.

Don't get too excited about this system cause it's not happening until January at the soonest as I'm way too busy right now. Maybe Silent will jump on it though!

See you Saturday...
 

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Let's discuss intercooling! Yeah, I'm going to go there again. Specifically, I wanted to go through some calcs that I made recently to determine the best possible A2A intercooler core dimensions and see if A2A is worth it. After looking around, I feel confident that I can put together a nice A2A system for less than $1000. Look forward to hearing input from you all.

Here's my math to get us to our desired info. If you all see errors, feel free to chime in and correct me.

S62 N.A. Flow Rate
(CID*RPM*.5*Ev)/1728
=(301.5*6900*.5*.85)/1728 = 511 CFM

Pressure Ratio
(14.7+9psi)/14.7 = 1.62

S62 F.I. Flow Rate
pressure ratio * N.A. Flow Rate = 511*1.61 = 823 CFM


INTERCOOLER SIZING

Internal Flow Area Required
40in^2 internal flow area required (I snagged this number from the attached handy flow rate/flow area graph)

Area of Charge Face
(Internal Flow Area)/.45 45% of charge face available for entry into air tubes
(40in^2)/.45 = 89in^2

Charge Air Width (3" core)
(89in^2)/3in = 30 inches

Charge Air Width (3.5" core)
(89in^2)/3.5in = 25 inches

The most ideal charge face size for an A2A intercooler ranges dimensionally, but if we were to limit core thickness to 3"-3.5" then we can get away with an intercooler that is 25"-30" long. Keep in mind that this requires charge air going from top to bottom and not side to side like a lot of crappy intercoolers on the market.

Here's a nice unit in this range…
TRV25 Series Intercooler 1000HP- TREADSTONE PERFORMANCE

INTERCOOLER EFFICIENCY
In a separate thread, Vortech V3 discharge temps were discussed and tested. Vortech sets discharge temps at 190F and testing confirmed this. A2A intercoolers tend to reside in the 60-70% efficiency range. A2W range anywhere from 75-95% efficient.

Max Temp Decrease (from an intercooler)
Discharge temp - Atmospheric Temp = 190F-75F = 115F

Temp Decrease (60% Efficient Intercooler)
115F*.6 = 70F


AIR DENSITY
w/o Intercooler = 190F and 1.62 boost pressure ratio
w/ Intercooler = (190F-70F) = 120F and 1.62-1.14=1.48 boost pressure ratio ***1.14 is our assumed intercooler pressure drop of 2psi

Non-Intercooled Air Density
(297K/361K)*1.62 = 1.33 times non-supercharged air density (532HP)

A2A Intercooled Air Density (60% efficient w/2psi pressure drop)
(297K/322K)*1.48 = 1.36 times non-supercharged air density (544HP)

A2W Intercooled Air Density (80% efficient w/2psi pressure drop)
(297K/309K)*1.48 = 1.42 times non-supercharged air density (568 HP)


CONCLUSION
If all these calculations are correct and fairly conservative, which they seem to be, it seems that A2A intercoolers will produce marginal performance gains with levels of boost 9psi and lower. Though I am willing to bet that fuel economy will be significantly better, accompanied by lower coolant/oil temps. Your thoughts?

how are you planning on adapting the i/c to the ess kit being its installed on the right etc? just trying to picture how the tubing is going to run?
 

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how are you planning on adapting the i/c to the ess kit being its installed on the right etc? just trying to picture how the tubing is going to run?
The Dinan S3 supercharger is mounted on the passenger side and has an A-A inter-cooler, doesn't it? Should be pics floating around showing that setup. This link shows the topside. Looks like discharge pipe must go down the RH side, across the front through the IC, and then back up the drivers side into the plenum.
Dinan S3-M5 : A Closer Look at this Beast of a BMW - Pelican Parts Technical BBS
 

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Similar to Dinan, but not exact, Dinan did not use a V3 SC, OP and I will be looking at this over the weekend and begin the R&D on this project.
 
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The Dinan S3 supercharger is mounted on the passenger side and has an A-A inter-cooler, doesn't it? Should be pics floating around showing that setup. This link shows the topside. Looks like discharge pipe must go down the RH side, across the front through the IC, and then back up the drivers side into the plenum.
Dinan S3-M5 : A Closer Look at this Beast of a BMW - Pelican Parts Technical BBS
awesome car, engine bay is disgusting. don't know how one could own that car with all the beauty under the hood and leave it so filthy. wish there was a better shot of the blower area. i still can't wrap my head around how the piping is routed.
 

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As you know, the S3's supercharger is mounted on the passenger side of the engine compartment. The pressure side piping drops straight down and runs under the radiator. Both stock fog lights are removed. The passenger side opening is the air intake while the driver's side is ducted to the A to A intercooler. From there the piping rises vertically and feeds the intake plenum. Due to the overall length of the piping, Dinan incorporated the so called 9th throttle body to mitigate any sudden pressure waves caused by an abrupt throttle closure while on boost. It works quite well. Supposedly Jim Conforti helped with the design.
 

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The most ideal charge face size for an A2A intercooler ranges dimensionally, but if we were to limit core thickness to 3"-3.5" then we can get away with an intercooler that is 25"-30" long. Keep in mind that this requires charge air going from top to bottom and not side to side like a lot of crappy intercoolers on the market.

Here's a nice unit in this range…
TRV25 Series Intercooler 1000HP- TREADSTONE PERFORMANCE
Hmmm.... That looks remarkably similar to

 

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Similar to Dinan, but not exact, Dinan did not use a V3 SC, OP and I will be looking at this over the weekend and begin the R&D on this project.
i was eyeballing mine today and was thinking the only way to make it work is have the blower outlet pointing down. i know you can loosen the hex bolts and clock the blower left or right.
 

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i was eyeballing mine today and was thinking the only way to make it work is have the blower outlet pointing down. i know you can loosen the hex bolts and clock the blower left or right.
The ESS kit is very hard to upgrade. This, I know as well as any one.

--Peter

And BTW, **** BROWN UNIVERSITY.
 
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