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pressure drop of NPR...


Bob_H

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Ok, did the search, and turned up vauge answers on this forum. Did the Google search and turned up nothing. I have heard 1.5psi,(but not at what input psi).

I know scottie you lost nearly 7psi to get 20 at the throttle body,(however it wasn't clear in those posts if you found another source of a leak, as I find 7 psi to be a bit excessive...)

So for 350-400 rwhp, are we talking ok? The following item is one I am considering, esp. if I can get one like it,(the guy has a few for sale), for less than $225:

Ebay NPR? intercooler

Ratedz,(from here), has the top bid on that one. The other he is selling,(two e-bay names, and appears to be bidding up his own auctions)...is the same one on the same background.

I am assuming since it is close to a 3 inch outlet, that it is the "large" NPR. Or do you think it is from some other truck? I wrote and asked him what it was from, so I'll let others know. I like that both inlet and outlets angle up and out the same amount.

-Bob

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I said especially if I can find one for less than $225. In my searching around on the two posters,(the one doing the auction you are bidding on), and checking the guy who pumped up the price in that auction,(turbo0 or similar), I found another finished auction for $227.50. So I figure the range is 225- less than 300. I think this guy buys NPR's,(again, noone has really verified it, and he/she didn't answer in their e-mail back to me),polishes the end tanks, and puts them up for sale.

I did something sneaky in my reply to them. I had asked if the measurements were absolute end to end, or just the core. Their response was from tank to tank. Which still leaves me wondering exactly what it was and they hadn't responded to what vehicle it came from.

So I wrote back asking if it was end of outlet pipe to end of outlet pipe or start of tank to start of tank. I also said that I had bid on their other auction,(which is the other name). We'll see what they respond. Bottom line, they are bid shilling,(pumping their own bid). I got suspicious when I saw on your auctions bid history that the same person had bid numerous times with noone else bidding....

I think there may be the same thing going on with the other auctions,(a new unregistered user with no named location).

Speaking of which, how do I find where someone is registered from,(what city), if they have no auctions? I tried the member search and it just said United States.

So noone has any figures on psi drop or exactly which one this is? The pictures I got from scottie's site show the "large" NPR as being a slightly different inlet and outlet,(he had the "large").

-Bob

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PS- here is the previous auction from the same seller:

E-bay $227 intercooler

(and if you look at the bid history, turbo_0 was the first bidder).

-Bob

And here is the trail I have followed:

Turbo_0's intercooler auction #1

And if you look at the bid history of that one, turbofan17 is in the bidding.....again, same background in the picture...

More to come...

Right now I can't get into the E-bay rules and such place. When I get to where it lets you chose a topic, it won't go past the first main topic to the subtopic. all other area I can select them....odd.

Another turbofan17 completed sale...again turbo_0 in the bid history...both in miami:

Turbofan17's sale

and another turbo_0 auction, but turbofan is not involved, but same picture:

turbo_0's auction

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Quick break from the game. He appears legit, as he has sold a few others. I just questioned the bid shilling,(bidding on his own items).

I can't really prove it, but assuming you get yours, and he offered me one outside of auction, I'll still report it as I think it is shady.

I'm looking forward to seeing how it fits. He just told me it was from an Isuzu truck, nothing more. I think they want to protect their "investment" and not reveal the exact model. I'm gonna do some searching on Monday to see what is available around here at the local JY's.

Ok, back to the game, Tampa is about to score.

-Bob

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Interesting... I met a guy about 5-6 months ago from Miami who said that someone broke into his rental lot and stole...yep, you guessed it... NPR intercoolers out of 20 some odd trucks. careful these don't burn your fingers :D:D

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Guest JAMIE T

I have heard of guys renting the trucks, and pulling the IC's and returning the truck sans IC. I wouldn't mind getting one of those IC's either. I'm eyeballing an APEXi core, I'll build my own tanks(I am the TIG master)

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If you start looking at the smallish white delivery trucks you'll notice that some have a NPR emeblem on the side of them. I believe there are several different models but, the one turbo guys are after is the NPR.

 

As I understand it the NPR is a good intercooler since it has good surface area and flows well. I would think that a prouperly size aftermarket unit would be better and easier to fit for not to much more money.

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So all this good info and noone has done any testing on pressure drop with it?

Oh well. I would not be at all surprised to know that those were stolen...

Think about it, 20x ~250-300 each....$5000+ for just polishing the end tanks, oh, and jumping fences.

-Bob

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Sorry guys but I have been up to my neck in alligators putting my car back together and trying to close a deal on a new daily driver.

 

A view of the other side would have been better but I am certain that is an NPR, the medium-sized one. As for the reference to me experiencing 7psi pressure drop, that happened when I tried to push 400+rwhp and that was through the big NPR. Remember, there are 3 sizes: the small which is the shortest and has smaller pipes pointing forward, the medium pictured here and the large which is taller and has less but much larger tubes.

 

Bob, if you are seriously thinking of 400rwhp, then I would say keep looking because you are going to reach that HP level all too easy and you WILL NOT stop.

 

Here are some pics of NPRs, a medium/large comparison and a large next to to a stock radiator. Yes, most NPRs come in through "Midnight Auto".

 

npr-compare.jpg

npr-rad.jpg

 

BTW, a lot of folks trying to push alot of boost through these small OEMs probably would be shocked at how much pressure they have and the heat that is generating. Only way to find out is to do what I did. Put a boost gauge on the compressor AND the intake and see the difference. I also have thermocouples at the compressor and TB to measure temps.

 

My advice is and always will be, do not use an OEM I/C that was used on an engine with less HP than a stock L28ET. Does matter on the engine as it is all about flow and HP=Flow.

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Searched and a post by SHANE. Good info on various intercoolers...

 

SHANE

Member

Member # 1238

 

posted February 18, 2002 01:45 PM

--------------------------------------------------------------------------------

well the closest they have to my model(mine is 4 years old) is 2-225 700cfm. i still think it is too small 9x14x3.5" i guess i will shop around then for a better I/C. i was afraid of the NPR cause of the thickness. here are some flow tests on NPR I/C's from turboford. in case anyone is interested.

 

DRHausee has an awesome program for calculating all of this. He is currently in rev 2 of the program. I have his first version and this is what I calculated:

First of all, some constants: Compressor efficiency is 71%, compressor inlet pressure is 14.7psi absolute, compressor inlet temp is 80°F and intake manifold pressure is 20psi. This is for a 2.3 with VE of 75% at 5000rpm.

 

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.

 

So it appears the Saab 9000 IC is slightly better than the Volvo.

 

Now lets look at the Dual Volvo IC (like mine) : at 340cfm and 291°F on the inlet side of the IC, the pressure drop is 0.29psi. The outlet temp is 94°F, heat rejected is 73063 BTU/hr, and the calculated heat exchange area is 3077 square inches.

 

I am not sure that these numbers are correct as Don's program looks at the numbers enters as being a single core IC. When the outside air hits the second core passing through, it is much warmer than the front row, so the numbers seem a little optimistic.

 

Now lets look at the Isuzu NPR medium duty Truck IC http://www.turboford.org/npric/ :

 

The smaller NPR IC: 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.

 

The larger NPR IC: at 340cfm and 290°F on the inlet side of the IC, the pressure drop is 0.07psi. The outlet temp is 111°F, heat rejected is 64237 BTU/hr, and the calculated heat exchange area is 2018 square inches.

 

Gentlemen! I think we have found a new intercooler! The big one (look at the attached link) is sweet! It will fit right in front of the ranger radiator, which makes it a great fit! Forget the starion, that thing is a turd. Now the downfall...the price, these things go for $250-300 on ebay.

 

--------------------

SHANE

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What they refer to as the "big NPR" in that comparison is what I refer to as the medium. The Large NPR is painted/coated black and very rare. I do not have a clue what year/model they came out of but I would venture a guess it is the FPR not the NPR. Don't take that as gospel as I just put my order in and wait for delivery :D .

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Scottie,

Thanks for the input. I have pretty much come to the same conclusion, but will still buy the NPR. Follow me on this one. I am putting the RB in my current Z while I do a suspension swap to a shell I will pick up in the next week or so,(the GRM budget car refered to in the buy/sell).

I will use the opportunity with the RB in my Z to work out all the electrical and running bugs. I won't push much over stock boost, maybe up to 12 psi or so. I will only have stock injectors,(440cc/min's), so 400 flywheel hp is about the limit. The "donor" should be ready for the RB in about 3 months. By that time, I can get a proper intercooler and sell the NPR for what I have in it, maybe more,(I am getting it for $275 shipped).

In otherwords, it is a good temporary fix while only pushing 300-350 rwhp max. When I outgrow it, up for sale it goes and in goes a proper one, a quick and easy fix.

BTW, the guy I am buying from say's it is 2.5 inches thick with 3 inch inlet and outlets, vice the 2.25 thick and 2.75 inlets/outlets you measured.

I'll guess that remains to be seen. I'll bet it is a 2.25 inch core.

-Bob

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I can see why you guys like this intercooler, after looking at 240hoke's photos what a nice fit, and here I'm trying to jamb in my Apexi GTR core, it will fit but will take some work to do so.

 

A lot of guys in my city take intercooler off of big rigs and cut them down and make end tanks. But i dont know how good they are.

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Hey 240hoke, very nice & clean set up. Mine will look pretty close to yours...I'm still contemplating on having all the pipes come out on the drivers side because I didn't want to use an electrical fan to clear the piping...but then again, it looks like I might not have a choice unless I mount the intercooler on an angle with the bottom of the IC pointing towards the car and the top tilted forward. Then I might have enough room to plumb the piping just behind the IC. I really wish Doug's web site (2+2 turbo monster) wasn't down...I know he was able to fit all kinds of stuff in front and behind his NPR cooler. Also, I wanted to ask you how you did the Z on the IC. I was going to put "turbo" on the face but didn't want to screw it up...did you just use a stencil? Cut out from cardboard? Thanks. cheers.gif

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