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Supercharging a 944 - Why so hard?

 
Old 12-21-2017, 10:34 AM
  #151  
jderimig
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Originally Posted by Ish_944 View Post
Wow, if I calculated correctly and this is true, then a single triple 140 mm radiator I was thinking about would be good for a mere 1300 HP. And I wanted to use 2 of them!
Oh, and these are available in 1, 1.5, 2 and 3 inch thicknesses.
The capacity doesn't add linearly if you stack them. If its 140mm square you have about 25 sqin. You would need then to subtract out the structure, I think the area is actually where air can flow. So I am guessing that is good for 350 to 400 HP. To get more you would need to run them in parrallel not series.

You also have to consider the pressure drop accross each cell. Those may not optimized for that as that is not a concern with processor cooling.

Please post a picture of what you are thinking about.
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Old 12-21-2017, 11:12 AM
  #152  
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it's not quite that easy...
AWIC cores need to be BIG to work. remember that on say a 944 at 5000rpm it's got to flow ~220cfm @ whatever pressure ratio the blower is pushing out, all heated to 150C and trying to get it to 50C on the other side.

that jaguar IC pictured above (factory rated at 325hp, good at 400hp) is about 4.5" high, 16" long, and about 7" thick.
the weak spot is the stock Jag front heat exchanger, rejecting the heat from the warmed up water back to atmosphere.

needs more heat exchanger and more coolant flow.

another example, this is the intercooler core for the supercharged 6.2L camaro/Cadillac, about 600hp.
https://www.dedicatedmotorsports.com...-p/ribctsv.htm
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Old 12-21-2017, 11:30 AM
  #153  
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Just got off the phone with Bell Intercoolers. For my application he suggested a core size of 4.2 x 6 x 3" core thickness which would be conservatively rated good for 230 rwhp. Since I am looking for ~225 bhp at the crank he said I could even go smaller than that. Reducing the core thickness to 2" would only have a small effect on efficiency. This setup would need 5 gpm of coolant flow.
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Old 12-21-2017, 11:46 AM
  #154  
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if that size would work, take a look at Setrab "type 6" 13-row oil coolers.
i looked at making my own AWIC using one of those...core is 9.5x4x2 thick.
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Old 12-21-2017, 11:50 AM
  #155  
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Originally Posted by V2Rocket View Post
if that size would work, take a look at Setrab "type 6" 13-row oil coolers.
i looked at making my own AWIC using one of those...core is 9.5x4x2 thick.
For the charge cooler or the coolant cooler? The above is a little long for what I would like to try which is to "stack" the IC right on top of the blower outlet and be within the envelope of the MB M62 blower.
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Old 12-21-2017, 12:00 PM
  #156  
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for the charge cooler between SC and cylinder head.

if thats too big, then go to your local auto supply store and ask to snoop around their collection of heater cores...
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Old 12-21-2017, 12:01 PM
  #157  
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Originally Posted by V2Rocket View Post
if that size would work, take a look at Setrab "type 6" 13-row oil coolers.
i looked at making my own AWIC using one of those...core is 9.5x4x2 thick.
Yes my friend had an Opel Ascona Fully restored and Modified with a 2.0 GM Engine and Eaton Supercharger, using an Oil Cooler
for a Chargecooler... the last I heard it was pushing about 320bhp




See Build link


R
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Old 12-21-2017, 07:37 PM
  #158  
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Originally Posted by jderimig View Post
The capacity doesn't add linearly if you stack them. If its 140mm square you have about 25 sqin. You would need then to subtract out the structure, I think the area is actually where air can flow. So I am guessing that is good for 350 to 400 HP. To get more you would need to run them in parrallel not series.

You also have to consider the pressure drop accross each cell. Those may not optimized for that as that is not a concern with processor cooling.

Please post a picture of what you are thinking about.
I meant these radiators and for cooling the coolant, not the charge.
http://www.frozencpu.com/products/18794/ex-rad-491/Alphacool_NexXxoS_Monsta_Triple_140mm_Radiator_-_80mm_Thick.html?tl=g30c95s931&id=teHpSQTV

With these, core and total area are practically identical. I don't think pressure drop is an issue at the coolant side. Those pipe-looking intercoolers are really nice and could be a great combination!
Moreover, PC pumps can do 300-400 gpm (1200-1500 liters per hour).
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Old 12-21-2017, 07:44 PM
  #159  
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Ish - to cool the coolant you want as big (surface area, not thickness) an exchanger as you can physically fit.
On a 944 chassis, you could get a cooler about 600mm wide by 350mm tall in front of/in place of the AC condenser...
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Old 12-21-2017, 08:05 PM
  #160  
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The other thing to consider for the coolant radiator is you can have a smaller coolant radiator if you have a larger coolant tank and play the duty cycle game. For a track car where you are on the boost alot then you certainly need the radiator capacity. But for a street car not so much.
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Old 12-26-2017, 06:46 PM
  #161  
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Latest CAD work on the stacked intercooler idea. Using the recommended core size from Bell Intercoolers (4.1 x 6 x 3" core thickness) I can fab (I think) a stack like this. Will need 6.7" of vertical space on top of the SC too fit. I was going to pull the alternator to see how much depth I would have but it 15F outside and my garage heater won't make it warm enough for me to work. So it will have to wait a few days. I worry about the sharp turn in air flow at the top, don't know if this a big concern or not (even if I have the space).

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Old 12-26-2017, 07:21 PM
  #162  
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the ford 3.8 SC had a similar sharp-turn outlet and they put some guide vanes on the underside of the outlet "hat" to direct the flow towards the exit.
i can take a photo later if interested.
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Old 12-26-2017, 07:29 PM
  #163  
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Originally Posted by V2Rocket View Post
the ford 3.8 SC had a similar sharp-turn outlet and they put some guide vanes on the underside of the outlet "hat" to direct the flow towards the exit.
i can take a photo later if interested.
So the vanes were "inside" the casting cavity? Yes a pic would be handy.
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Old 12-27-2017, 10:13 AM
  #164  
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not my photo but you get the idea.
to clear the thunderbird hood this "hat" is only maybe 1.5" high but the pipe connection is 70mm OD, all the flow gets squeezed thru a ~1.5x2.5" slot that the vanes are pointing at.
interestingly the Tbird SC guys have a product called a "raised top" that is this thing but 3/4" or 1" taller to nominally make that "slot" less restrictive - but it doesn't actually seem to change anything.
people have tapped this hat pre and post-slot and found like 5 extra PSI on the SC side of the slot vs the discharge pipe but it doesn't seem to cause any noticeable power loss. that air is getting out...

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Old 12-27-2017, 02:41 PM
  #165  
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Spencer, thanks for the pic. Those would be easy to add. I was picturing the vanes differently like trying to bend the flow. But that would be a manufacturing nightmare.

But you are right it all has to come out, positive displacement is positive displacement.....just makes the sc work a little harder.
I updated the config a little, increased the flow area of the core (5.3x6 instead of 4.1 x 6) and reduced the core thickness to 2.25". The lower piece with the original dimensions wasn't easily castable anyways. Making it bigger makes proper draft on the pattern possible. That brings the total stack height just under 6 inches. Still too cold in the garage to work today though.
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