blau928

Hi All,

I just got done with my AWIC tank install after waiting on the tank to arrive several weeks after designing it and having it built. I think it turned out great. The rear bumper support is modified to accept the tank, and the bolts secure it to the bumper support with threaded bungs welded on the inside of the tank. It fits snugly against the body, and the side mount inlet (upper) and outlet (lower) are AN-12 fittings. The fil and vent valve are 1/2NPT, and are visible on the top of the tank with the blue plastic plugs still intact.

The rear compartment is modified to be able to access the fill port and vent valve by opening the rear hatch. Once the bumper cover is attached, it is all hidden from view and no signs of the tank show and or protrude..

Measure 10 times, build one time, and not too shabby indeed..

Then again, it's not for everyone...

First pic is tank before installation you can see the 4 screw in bungs facing the camera, and the others are various views of it mounted. Last is the rear cover back on the car for test fitment.

Enjoy the pixx.

AO

Dude! That thing is HUGE! What's the capacity? 6 gallons? Why so big? As long as your heat exchanger can bring the coolant down to ambient, there's no need for anyhting this big. Most of us SCed cars just use the washer reservoir. That's gonna be a lot of extra weight - not to mention it's ability to slosh from side to side. Nice work though.

BC

I think its great. A large reservoir will be good for longer bouts of boost heating the water. To go all out, maybe put two radiators in the system as well, and use some of the water to spray a mist onto the front radiator for the A/W circuit.

You could even plumb a AC core next to it to cool the aluminum of the tank from the rear AC plumbing!

SharkSkin

Rich, very nice! Ought to help a bit with traction, though adding weight that far out will tend to keep it sliding once the rear breaks loose in a corner. Probably no better place for it without using up space in the passenger compartment though. Are you replacing the washer tank with the dry sump tank?

Andrew, the capacity is mentioned in the thread title. Also, Rich is going to be using much more efficient heat exchangers in the manifold than the typical setup, so shedding the extra heat may be a bit more of a challenge than usual. A larger tank provides a bigger margin, and it's not going to slosh if it's full.

AO

Yeah... I see that now. 10 GAL! Wow! Still, assuming the car weighs 3500lbs. and makes 500RWHP, that's 7lbs per RWHP. You've added about 100lbs (wet). That means you need to pick up 14 RWHP to stay equal. Granted the car (engine) may be safer to drive now at full boost.

Also, if the ICer is more efficient, then what's needed is a better heat exchanger, not a larger reservoir. If the heat exchanger can keep up, you theoretically don't need a reservoir.

Not knocking the workmanship... just trying to understand the thought process.

SharkSkin

Andrew, knowing Rich, he's not going to settle for a mere 500RWHP. From what I've seen, and from my conversations with him, every component part is being reconsidered with the intent of improving strength, safety, reliability, etc. but obviously he's the best one to discuss the specific thinking around this mod.

My best guess is that he has calculated the amount of heat he will draw from the charge air (boost levels will probably be beyond what we've come to see as typical) vs how much he can pull out at the other end and decided that he needs a big buffer. That may seem pretty obvious but I'm just trying to emphasize that I have yet to see him make an expensive mod without good reason.

AO

Todd Tremel in Green Bay who was making almost 30 pounds of boost went to an A-A IC to combat his heat buildup. The benefint of the AAIC, obviously, is that you don't have to carry all that water - the downside is that it's less efficient.

I wish I had those kind of skillz.

blau928

Heh heh heh......

Dave's correct in his evaluation above.....

Yes, Dave, the dry sump tank MAY eventually live where the washer tank lies. I have another spot for it that I have been keeping in mind and need to measure for 5/6 gallons. (I think it will be possible so I can save the washer tank as I like clean windows.... )

The AWIC tank is sized based on the heat absorbtion of the rated capacity of the current intercooler cores, and also on the future upgraded motor and the s. (The thermal capacity of the entire system.)

The heat exchanger in the nose will be dual units provided I can get them to fit.. (I am working on it now..)

The comment about using the washer tank is based on mild driving and to my ignorance, no scientific claculation about the heat loads of the system, rejection rate of the heat exchanger, the coolant circuit time, and the thermal reserve of the system. Maybe others have done it, but like I said, I'm possibly ignorant of the data, as I have not seen it.

The flow rate of the pump is also sized based on the engineering requirement of the cooler cores and the system. The only part of the system not calculated is the additional volume that will be held in the AN-12 lines plumbing the system. (There is engineering data to support the requirements of the tank size, line size, pump rate etc.)

This system is being built for ORR type driving with everyday civility. I am planning on taking the car to europe and driving it in Germany for a month after it's finally done. Of course some days on the N'ring will be in order.

In the good old USA, there is no need to build to such capacity as the vehicle will not be at significant load for very long, as the driver will be in jail. On an unrestricted A'bahn in Germany, I can drive more than 1hr flat out and not worry about anything other than if the Sunday driver that just pulled into the motorway sees that I am closing at 300/KmH.... No helmet, no cage, no fire suit, no gloves, just a Sunday drive in the country to see a friend. (I have done it countless times, and want to do it with something I built..)

Anyway, I'm maybe ranting here..

Like I said, it's not for everyone..

A few notes/explanations to keep in mind on some other comments made...

Traction: 335's or 355's will be going under the rear once I get to Louis and his fenders.... (It now has 305 Toyo R888's)

Weight: The 10 gals is about 80Lbs including the weight of the tank...(Yes, I modeled that in CAD also.) Further, I will be replacing the S4 12-way power seats with GT3 seats that save about 50lbs each over the power seats. I have a Recaro SPG which is on the driver's side already.

Power: 500 RWHP is the minimum, the system I have designed is for 1200HP Crank, but can be expanded further evry easily.. (I doubt the block would live though...)

AC chilling: I am still looking into it, and know it can be done to improve bursts of performance at max load/wot/etc.. Still need to calculate some data, and also decide on placement of the AC circuit... (I have a place in mind, but will get to it later as the current AWIC setup is more than adequate for the system at this point...)

The goal is to have a 928 with creature comfort, and more than adequate additional reserve power for leaving most things behind.

Hope that explains a bit more..! Of course there is a list a mile long with other things that can't be seen that I am doing......

blau928

Thanks for the kind words..

It won't slosh, it will be filled and bled from the vent valve...

See my other comment for the sizing etc..

blau928

Thanks Brendan,

Yes, the idea is to be able ot sustain max load for a long time a la Autobahn..

I may puy a CO2 cryo spray to "cheat" in certain conditions, but it may not be neccessary if I get the AC line plumbed in. (See my other post..)

blau928

This statement is not true. You need to take the total system into consideration. The reservoir is for thermal reserve. If you just have 2 exchangers with minimal coolant, then the exchanger for the coolant circuit will be overwhelmed if the load in the system exceeds the thermal heat rejection capacity of the exchanger. In such a case, one is better off just using an Air to Air unit.. With AWIC's, the thermodynamic equation needs to be addressed fully..

blau928

Andrew,

There's always a tradeoff... I chose water for very specific reasons....

If you have a lot of $$$$, you can buy skillz....

On another note, it's not about boost pressure. It is about mass airflow. The heat in the intake charge comes from the pressure, and pressure is resistance to flow. So, you can make more power flowing more air (Mass) at a lower pressure, as the intake charge will stay more dense, and also cooler... This is the part that few seem to understand... However, it is all in a thermodynamic equation...

Same with fuel......

My $0.02 for today....

auzivision

I’m somewhat new to this subject and trying to learn.

How is it a water system is more efficient. Don’t you have air cooling water cooling air in one system (2 steps/exchanges) and air cooling air (1step/exchange) in the other? One would think one step would be more efficient since there are losses (inefficiencies) associate with each exchange.

I totally get the fact that the location of hot air versus location of cool air has a lot to do with why one might choose water based system… liquid is easier to plumb and an effective medium for transporting heat.

What am I missing?

AO

If you have a hot pan (the intercooler) which is a faster way to cool it down? Blow a bunch of room-temerature air across it, or pour room-temperature water on it?

Water, right? Then the key is to get that water which has sucked the heat out of the intercooler, back down to ambient temperature. This is where th eheat exchanger comes into play.

WallyP

I would be seriously looking at finned tubing to and from the tank...