Turbo's and air density.

Thanks for the pointers. I will search that. So inlet PR doesn't affect map shift much but what about inlet temperature? Talking compounds here. If the secondary(s357) sees a 400+ inlet temp compared to a 150+ inlet temp obviously, it will take a less secondary turbo shaft horsepower to recompress the air again to say a 3.0PR. Just wondering how much better a set of compounds will run, specifically a 57/65/14 over 72/83/1.1 if I can run a W/A intercooler in between stages and reduce the inlet temp to the secondary. This is my plan ateast, and I'm trying to see it on paper. lol.
 
I am expecting a 320 degree drop in temperature going into the secondary charger. Probably won't make a difference, but it's something to do during the winter.
 
RonA said:
I am expecting a 320 degree drop in temperature going into the secondary charger. Probably won't make a difference, but it's something to do during the winter.
Click to expand...

I would think it would make a huge difference in lb/min?? The secondary charger should be able to actually recompress the air again at such a lower temperature drastically increasing lb/min correct? I was under the impression when inlet temps get over 400* its pretty hard to recompress with any efficiency?
 
Turbochargers are volume and pressure ratio devices. They take a volume of air and compress it to various pressure ratios.

LBs/minute only comes into play when one assumes an air density going into the turbocharger. This is often done to simplify calcs for turbos used by themselves.

Interstage cooling totally changes the performance of compound chargers. It increases the density of the air going into the secondary charger, which increases the capacity of the secondary charger, on a lbs/minute basis, it increases the efficiency of the secondary charger and greatly reduces the discharge air temp.

I think its very worth doing.

I'm wondering why people think they need to run a secondary rad and pump to do an air to water interstage cooler. Couldn't one use the primary radiator and take coolant directly from the water pump before it circulates through the block ? Wouldn't that be near ambient temp ?
 
me2 said:
Turbochargers are volume and pressure ratio devices. They take a volume of air and compress it to various pressure ratios.

LBs/minute only comes into play when one assumes an air density going into the turbocharger. This is often done to simplify calcs for turbos used by themselves.

Interstage cooling totally changes the performance of compound chargers. It increases the density of the air going into the secondary charger, which increases the capacity of the secondary charger, on a lbs/minute basis, it increases the efficiency of the secondary charger and greatly reduces the discharge air temp.

I think its very worth doing.

I'm wondering why people think they need to run a secondary rad and pump to do an air to water interstage cooler. Couldn't one use the primary radiator and take coolant directly from the water pump before it circulates through the block ? Wouldn't that be near ambient temp ?
Click to expand...

I agree exactly. All I'm trying to figure out is if the inlet temps and PR change on the secondary from ambient how will it affect its map and how will lb/min be affected. I guess a person would have to see what the outlet water temps are on the engine cooling system after exiting the radiator. If they arent low enough you could be heating the air. Also I have heard of people saying that the W/A would heat the water also and the stock cooling system couldn't handle the extra load and would not be able to cool the engine or W/A effeciently. I think most of this is speculation and no one has actually done it, although I do plan on running a W/A when I build my compounds. I am saving money right now to do it. Takes a little more coin than usual lol. LOL
 
Ghostman said:
I agree exactly. All I'm trying to figure out is if the inlet temps and PR change on the secondary from ambient how will it affect its map and how will lb/min be affected. I guess a person would have to see what the outlet water temps are on the engine cooling system after exiting the radiator. If they arent low enough you could be heating the air. Also I have heard of people saying that the W/A would heat the water also and the stock cooling system couldn't handle the extra load and would not be able to cool the engine or W/A effeciently. I think most of this is speculation and no one has actually done it, although I do plan on running a W/A when I build my compounds. I am saving money right now to do it. Takes a little more coin than usual lol. LOL
Click to expand...

Actually member gs1000 has done exactly what you are describing running a water/air cooler off the water pump outlet for inter-stage cooling in a compound turbo setup.

http://www.competitiondiesel.com/forums/showthread.php?t=134323
 
I'm more interested in seeing if it works than actually making a permanant install. I can see using it to dyno, but other than that it would have to be a big improvement hp and egt wise to justify using it all the time. I have heard not to expect any egt drop and power claims run from zero to maybe 100hp.
Zero isn't so great, 100 would be pretty nice. 50 would be no big deal. Running cleaner due to more lbs/min from the secondary might be another benefit. I'm also curious about how it will affect the flow from the primary. If the air on the outlet side is more dense than the air on the inlet side but the pressure on both sides is the same... well, you see why it's interesting.
 
I can't believe I missed this thread. You will be happy. It sounds like the cooler is coming from Bell.
 
joefarmer said:
I can't believe I missed this thread. You will be happy. It sounds like the cooler is coming from Bell.
Click to expand...
No. I bought a new HTT intercooler and welded an aluminum water jacket all around it. It's a bit large but should cool well. I plan on mounting it on the roof and using 4" muffin fans inside the piping to keep the velocity of the air up since it has to travel so far. Got the idea from watching Deathrace 2000.
 
straight 6 roar said:
Exactly, how friggin hard would you have to work to brake at the same rate?

My terminology might have been misleading but raising fluid to XX psi versus gas takes less work.


I'd definitely check IAT with your current intercooler before doing this whole setup. 50* drop in IAT and slightly better secondary efficiency isn't gonna gain much hp.
Click to expand...

Just to add to this, Work=Force*Displacement.
So to compress a liquid obviously takes much less "work" in this sense.
 
Big Blue24 said:
Actually member gs1000 has done exactly what you are describing running a water/air cooler off the water pump outlet for inter-stage cooling in a compound turbo setup.

http://www.competitiondiesel.com/forums/showthread.php?t=134323
Click to expand...

I have changed to a closed loop with electric pumps and a heat exchanger. First I had it plumbed into the engine cooling system and had the water return to the engine where the trans heat exchager used to return. When towing the hot water from the intercooler would overheat the engine. If you returned to the radiator it would probably work well.
 
RonA said:
No. I bought a new HTT intercooler and welded an aluminum water jacket all around it. It's a bit large but should cool well. I plan on mounting it on the roof and using 4" muffin fans inside the piping to keep the velocity of the air up since it has to travel so far. Got the idea from watching Deathrace 2000.
Click to expand...

Before anyone actually does this, I was kidding.
 
gs1000 said:
I have changed to a closed loop with electric pumps and a heat exchanger. First I had it plumbed into the engine cooling system and had the water return to the engine where the trans heat exchager used to return. When towing the hot water from the intercooler would overheat the engine. If you returned to the radiator it would probably work well.
Click to expand...

Was it able to cool your outlet temps though at all times? I'm contemplating pulling from radiator return and discharging after t-stat.
 
RonA said:
No. I bought a new HTT intercooler and welded an aluminum water jacket all around it. It's a bit large but should cool well. I plan on mounting it on the roof and using 4" muffin fans inside the piping to keep the velocity of the air up since it has to travel so far. Got the idea from watching Deathrace 2000.
Click to expand...

RonA said:
Before anyone actually does this, I was kidding.
Click to expand...

Thank you for clearing that up I had to google muffin fans. Million dollar idea. They would work good pre-slitmowheel for sure.
 
Don't use engine coolant, as then you would be heating up the air. Normal engine operating temperature is 195 deg's F. Very warm, and would be a wasted effort on trying the liquid to air intercooler.

Ron, since your truck is more race/dyno event configured I would run two liquid to air intercoolers (one for each turbo stage) and remove the air to air intercooler. Most dyno events there is no moving air going thru the cooler anyways. Drag racing the engine compartment acts like a parachute at high speeds. I would block in the front rad and limit the amount of air going into it.

I would build an ice cooler (an old mini fridge would work) and put it into the cab or truck bed. Wrap up two coils of copper tubing and place them inside the fridge. Plumb them up to the engine compartment (have the lines isolated good, so you don't heat up the fluid). Dump in water and ice into the fridge. For the race event you could place a small amount of dry ice on top the ice water, which would freeze everything up good. You will also require glyco/water 60/40 mix for the intercooler. This way you could have 18 to -50 deg's F cooling fluid liquid for your intecoolers.

For a even better air cooling effect would be to spray a shot of NOX after/before each of the cooler.:evil Just hide the lines out of view.:hehe:
 
Mike Holmen said:
Don't use engine coolant, as then you would be heating up the air. Normal engine operating temperature is 195 deg's F. Very warm, and would be a wasted effort on trying the liquid to air intercooler.
Click to expand...

1. That is the temp of the coolant coming out of the block going into the rad. The temp of the coolant coming out of the rad is quite a bit less.

2. In high boost applications, the air temp is going to be more than 195F, so even hot engine coolant would provide some cooling benefit.
 
me2 said:
1. That is the temp of the coolant coming out of the block going into the rad. The temp of the coolant coming out of the rad is quite a bit less.

2. In high boost applications, the air temp is going to be more than 195F, so even hot engine coolant would provide some cooling benefit.
Click to expand...

I agree with your train of thought. I need to determine the temp of the engine coolant exiting the radiator. If it is low enough it may make sense to use it. My ambient temps 10 out of 12 months are above 80* so I'm thinking most of the time the outlet temps will be over 150*. Engine coolant just might work. Just have to get someone with a temp gun to tell me the temp of the exiting coolant from the radiator.

Sent from my LG-P930 using Tapatalk 2
 
Ghostman said:
I agree with your train of thought. I need to determine the temp of the engine coolant exiting the radiator. If it is low enough it may make sense to use it. My ambient temps 10 out of 12 months are above 80* so I'm thinking most of the time the outlet temps will be over 150*. Engine coolant just might work. Just have to get someone with a temp gun to tell me the temp of the exiting coolant from the radiator.

Sent from my LG-P930 using Tapatalk 2
Click to expand...

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