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Intercooler Specs "very intresting"

D

DeathWagon

New member
Joined
Feb 6, 2003
Location
Under the hood of kennys car!!!
I got these from a 240SX fourm I am on also just thought I would pass them on.

I also found some neat stats for stock ic's:


The NPR IC(Med): at 329cfm and 290?F on the inlet side of the IC, the
pressure
drop is 0.09psi. The outlet temp is 130?F, heat rejected is 55553
BTU/hr, and
the calculated heat exchange area is 1404 square inches.

Starion IC : (the bigger one) at 324cfm and 292?F on the inlet side of
the
IC, the pressure drop is 0.29psi. The outlet temp is 139?F, heat
rejected is
52287 BTU/hr, and the calculated heat exchange area is 1217 square
inches.

Saab 9000 IC: at 332cfm and 295?F on the inlet side of the IC, the
pressure
drop is 0.81psi. The outlet temp is 123?F, heat rejected is 60350
BTU/hr, and
the calculated heat exchange area is 1602 square inches.

Volvo IC: at 331cfm and 293?F on the inlet side of the IC, the pressure
drop
is 0.55psi. The outlet temp is 126?F, heat rejected is 58809 BTU/hr,
and the
calculated heat exchange area is 1539 square inches


Granted 331cfm isn't all that much, but it gives you an idea of the
difference between the npr and your Volvo ic. Those npr intercoolers
are stoopidly popular down in central America.

http://www.rx7club.com/showthread.php?s=&threadid=255658&highlight=npr

http://www.15psi.com/ic_tests.htm
 
Maybe I'm just tired and reading that wrong............. :e-shrug: but why are people flocking to NPR Intercoolers when the outlet temp is lower with the Volvo Intercooler.............


From the specs, again I'm tired and if I'm reading this right, I'd rather have the Saab intercooler if anything............, it flows 1 more CFM, outlet temp is 3 degrees cooler than the Volvo Intercooler, although the Volvo Intercooler seems to flow more CFM than the NPR and have less outlet temp.
 
Are those specs on the later generation volvo intercooler found on the 92 and later 700/900??

Thanks,
Stephen
 
I have been thinking about this subject for a bit...
...one thing that the test might have left out a bit was how fast the cars were going? Were they the same car, was the test regulated where the air source could be regulated and the heat amount could change, eg outside of a car in a controlled envirnoment?
I have a theory about the later volvo IC, which was only paired with the TD04 13C in the US (T28 in europe I think). The later volvo IC has fairly small inlets and is somewhat narrow. MY theory is that it doesn't flow super well, but that at the lowly 6.6-7.7PSI the B230FT runs volvo wanted to exchange as much heat out as possible and maximize heat sinking ability and throttle response by running a small turbo and small plumbing. THe endtanks on the later volvos were just plain improved over the old kind, and the mounting was updated to go with the fatty 940 rad/trans cooler.
Volvos on a hot day in traffic suck, the IC is soaked and does not shed heat super fast, infact at a few PSI with the AC on I would guess you are having more of an interheater than an intercooler.
Also, look at the absolutely disgusting pressure drop on the volvo and saab ICs, assuming everything else is equal and you ran a large efficient turbo on a volvo IC I would guess that the cooling for the big turbo would not be a huge issue, the volvo IC would just hold up the show with all that nasty pressure drop after 300 some CFM.
John lane did not report tons of difference in IC outlet temps when he went to a PS IC over his saab thing, but I remember him mentioning that the pressure drop improvement infront of the T04 on his car must have been significant as his top end power improved a good bit. Also keep in mind that pressure drop will rise dramatically after a certain CFM because of the power or exponential relationship with gasses flowing through something. THe NPR may not be great, but if you are flowing 600CFM and your volvo IC looses 2.5PSI or more, you are talking about alot of air loss on a large turbo at that pressure. If I could remove the AC and make the fan come on at a certain IC temp then maybe my car wouldn't be such a pain in stop and go.
 
***Haven't slept in a couple days and posting seemed like a good idea...***

The only information missing is that data which occurs at any other conditions (read: cfm). While these conditions are excellent as they represent the upper flow potential for our motors, what happens when we double the stock boost?

If we argue that the intercooler isn't going to hold up to "much more" boost due to increasing losses, why don't we consider if the volvo intercooler is more efficient at lower boost/temps/flow. Wouldn't we then get the same power with greater efficiency at lower boost/temps/flow?

Perhaps I'm arguing semantics and the differences I'm talking about are less than trivial... and if I'm totally off-base then I know to expect the appropriate bitch-slapping :wink:
 
I think the Volvo IC is fine for 300 cfm, or maybe 200 hp. Its above that point that it becomes worthwhile to look for a better IC. Former TB member Bill Watson tested the efficiency of the Volvo IC on his 87 745T AW71 in an article that appears on the website under specifications and then under intercoolers. I have read other tests of the IC over the years, and none have been particularly favorable. There are better OEM IC out there. Autospeed recently tested about 25 IC, and the Volvo faired poorly in the tests run. The late Gus Mahon also ran some admittedly rudimentary tests on salvaged IC and the Volvo faired poorly. On the other hand, it won't stop you from making good power. There is a Ford Mustang 2.3T that has run in the 11s with a Volvo IC. And John Lane ran one on a car that made possibly three times the power of a stock 740T. I don't know the specifics of the tests run on the Nissan, but the tests look to be thorough and at the limited power level tested, the results were fine. This goes to show the value of good testing. If your IC is giving you less than 1 psi pressure drop and is in the range of 70% efficient, then you should probably spend your money on other improvements first. Its my view that the Volvo IC, with a core that lacks internal fins, would be better in a front mount location -- without an AC condenser in front of it. That's a quick way to boost efficiency. If you doubled the core and used custom end tanks, you would also address pressure drop and the weakness of the plastic tanks. This has been done before, but is best left to someone who can aluminum weld since paying to have it done raises the cost to the point where you might find another IC that is just as good.

Philip Bradley
 
Just to chime in a two cents worth here. I would think the lower pressure drop would help boost response and throttle response since the intake restriction is less. Plus in reading those tests it seems like the same amount of cooling done with a lower pressure drop is the best situation of all.

Another thing I notice is what size NPR did they test? The NPR is listed as Med? There is a large NPR like what Doug is using. I think that may be bit better than the med size one. But, from reading that I'm not sure which
one they tested.
Best regards,
 
When I swapped my stock 740 intercooler for the large-size NPR intercooler, my boost gauge changed from 14 psi max to 15.5 or so. That means I had 1 or 1.5 psi less pressure drop, or in English, I got a little over one pound of boost at the same turbo setting by virtue of the new IC.
 
"Maybe I'm just tired and reading that wrong............. but why are people flocking to NPR Intercoolers when the outlet temp is lower with the Volvo Intercooler............. "

Becuase that is at 300 and whatever cfm. What happens at about 500-700 is actually more important. This is just a standard test procedure that needs to be understood to be interpreted correctly. The heat rejected is misleading too, as shown below:

These are the powerstroke specs from turboford:
Flow: 351cfm.
Inlet/outlet temps: 289/92
Pressure drop: .02
Heat rejected: 73305 btu/hr
Calculated heat exchange area: 3278 square inches.


Obviously the test is kinda silly on a powerstroke, it hasn't really noticed it's even in use yet at 351cfm as is seen by the 0.02psi pressure drop. That's just hilarious. So, you might look at the heat rejection and see it's only about 50% more than the volvo (well, that is still a lot, but comparatively...)

But the point is as Phil alluded to the volvo ic is about maxed out during this test, where as the other ic's would likely keep rejecting more heat as the flow through them increases. This is best predicted via the pressure drop- which alludes to the intercooler's actual flow capacity, and via the calculated total heat exchange area.

People think pressure drop is good so that the turbo doesn't have to work as hard but that is not actually the point since the backpressure introduced at the turbine from a couple psi is generally negligible on a properly sized turbo.

The point is, each square inch of heat exchange area is capable of radiating a certain amount of heat energy per minute, but if you took a huge core and put a 1/4" inlet and outlet on it, it wouldn't matter how much heat it could radiate, sinc eit can't get the heat INTO the core at a rate that can keep up to the rate at which the radiating surface can dissipate it.

Conversely, a plain old peice of pipe would flow very well and allow a lot of heat energy to pass through it, but it's radiating surface is both small and inefficent, which means the rate of heat rejection cannot keep up with the rate of airflow.

So, you need both. The NPR has a fairly low pressure drop, which suggests it may, at higher flows, continure to reject heat after the volvo ic "chokes". Also, while the Volvo IC has a larger heat calculated exhange area... oh have to go... I will continue this later...
 
Well pressure drop was where i was going with this little bit of info. Also think about the fact that the higher PSI boost you run the hotter the outlet temps on the turbo will be because you are compressing more. If your turbo has to make 20psi before the turbo and only get 15psi to the engine there is just more heat created that the intercooler has to dissapate. Anyways hope you all enjoyed the info
Sam
 
lilpaz said:
It looks like there is only one IC... :???:
Click to expand...

You didn't think he'd use three Volvo intercoolers and keep the stock end tanks, or keep the end tanks separate, did you? I guess I needed to say "three Volvo intercooler cores in a sandwich with custom end tanks that ran all three in parallel".
 
Npr intercoolers have a better surface area than most of the spearco coolers on ebay, I think both are great intercoolers (having seen both up close and personal) altho getting the npr to fit would be easier than getting the spearco to fit, as they're geared more towards jap cars that have larger "front mouths" than ours do. plus the npr is cheaper :)
 
Couldn't get to a computer to finish my comments.. basically, the other thing is that heat exchange area is misleasding as well when left on its own, as a given amount of heat exchange area on a Volvo ic with no internal fins for examnple, can't be directed compared to a internally finned core.

Basically, quality of the area as well as quantity is an issue.

As far as the spearco, depends on the size, where it could be mounted, endtank design, etc, etc.
 
There was a good interview of one of the Spearco engineers in one of the car magazines in the last year. I have it somewhere. Essentially, the engineer admitted that when Turbonetics bought Spearco, it made Spearco go mass market and produce the cheaper tube and fin cores that the Japanese car hotrodders wanted, instead of the stronger and more expensive bar and plate units. Both can do well, but in a front mount that is subject to road debris, the sturdier unit is more desirable over time. Also, the heavier bar and plate design has a significant heat sink ability that the light unit does not have. Depending on driving use, the heat sink effect can be important. The endtanks are also important. Spearco is selling the new cores cheap, and some resellers are adding cheaply and poorly formed endtanks. The Spearco bar and plate design cores were typically mated to Spearco heavy cast aluminum endtanks that further helped the heat sink effect. The Spearco name is not the guarantee of quality that it once was.

Philip Bradley
 
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