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-   911 / 930 Turbo & Super Charging Forum (http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/)
-   -   Strip/remove paint off factory intercooler? (http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/564579-strip-remove-paint-off-factory-intercooler.html)

Tilikum Turbo 09-15-2010 01:50 PM

Strip/remove paint off factory intercooler?
 
I was under the impression the stock intercooler was anodized black, but it's actually painted. I want to find a procedure to remove it(is this a simple DIY job?), and apply paint remover to the outside.

Anyone one else remove theirs, and strip it down to the bare metal for additional cooling/heat transfer? I don't want to go aftermarket intercooler, which leads down the slippery slope of endless mod's/larger turbo, etc. Want to leave it basically stock.

Here in So Cal, we don't have much problem with salt/rain/corrosion, so I am not worried to run it as such.

David 09-15-2010 02:27 PM

It still probably transfers heat better with the thin layer of black paint.

Instead of spending time on the stock intercooler, why not spend your free time scouring the internet for a used aftermarket direct replacement.

esotoracing 09-15-2010 02:34 PM

stripping the paint wont give you any noticable cooling effects. +1 on aftermarket direct replacement or wait and see if your budget allows for Rarlys D/R cooler.

Schwarzeritter 09-15-2010 02:45 PM

There are a verity of solvents that can remove it. But it get's really time consuming and is not pragmatic. I mean you can, not to discourage you. PM if you wish to know which chemicals.

Although I think going with high quality aftermarket inter-cooler is most pragmatic both in time and in cost. Unless you are going for the simple yet satisfactory feeling of ( I am doing this because I can, and I like working on my car thing. )

Sorry to hear that you got something other then intended.

mark houghton 09-15-2010 02:50 PM

Whatever you do, don't use any caustic-based strippers (caustic, as in a base vs. an acid). Aluminum and caustics = no more aluminum + hydrogen gas.

Used to make hydrogen balloons as a kid, using aluminum foil and lye solution in a pop bottle. Neat stuff, but not on an IC.

cole930 09-15-2010 07:48 PM

Tape all the openings and have it glass beaded.

Cole

Tilikum Turbo 09-15-2010 08:30 PM

Quote:

Originally Posted by David (Post 5562998)
It still probably transfers heat better with the thin layer of black paint.

Instead of spending time on the stock intercooler, why not spend your free time scouring the internet for a used aftermarket direct replacement.

Hello David,
I have to disagree with your first statement, so I will give you a professional opinion(as an engineer).

An intercooler is basically a heat-transfer device, and maximizing the delta-T(change between inlet and outlet) will increase it's efficiency. Any 'medium' or buffer that stands between that transfer reduces the delta-T(and that includes paint, regardless of how thin it is. Think of sleeping on a summer night...blankets are like coats of paint on your body. Thick...not so good when it's hot. Thin sheet, much better. No sheet, and maximum transfer of your heat to the surroundings.

Now, if we remove that paint off the stock intercooler, there will be some increase in efficiency(hence more power), but is it significant? I would estimate at maximum boost, maybe tops a 0.75-1.0% increase(2-3 HP). To be more qualitative, VERY controlled testing would have to be done to validate that number, but I'm confident it would be in that ballpark.

An aftermarket, direct replacement will not only cost money, but typically will create more turbo-lag, and will require a different turbo to get the same flexibility/drivability out of the motor(and I want the present system to be seam-less, as I have virtually little or no lag with my present 3.3L...:D).

I'll provide pic's once it's done.

Tilikum Turbo 09-15-2010 08:33 PM

Quote:

Originally Posted by cole930 (Post 5563594)
Tape all the openings and have it glass beaded.

Cole

I might look into that. :D

Thanks.

spence88mph 09-15-2010 09:29 PM

Quote:

Originally Posted by Tilikum Turbo (Post 5563659)
An aftermarket, direct replacement will not only cost money, but typically will create more turbo-lag, and will require a different turbo to get the same flexibility/drivability out of the motor(and I want the present system to be seam-less, as I have virtually little or no lag with my present 3.3L...:D).

Agree on stripping the intercooler, lots of ricer guys have done this in the past and reported lower temps, I've seen old black intercoolers stripped and they can come up looking new. I would highly doubt you would notice the difference in performance though but it should look pretty sweet!

People are suggesting you change intercooler largely cause of the stock 930 intercooler's core, which is poor in comparison to more modern cores that will flow better and cool the charged air more efficiently. Lots of info on the stock intercooler here, most pretty negative...

esotoracing 09-16-2010 08:31 AM

Yes......not to discourage you. If you like working on your own car and want a cool little project and have a nice looking bare aluminum IC, then you can polish it a bit and should look prety good.

P.S. higher flow rate aftermarket IC will give you less lag that restrictive oem IC

David 09-16-2010 10:47 AM

Quote:

Originally Posted by Tilikum Turbo (Post 5563659)
Hello David,
I have to disagree with your first statement, so I will give you a professional opinion(as an engineer).

An intercooler is basically a heat-transfer device, and maximizing the delta-T(change between inlet and outlet) will increase it's efficiency. Any 'medium' or buffer that stands between that transfer reduces the delta-T(and that includes paint, regardless of how thin it is. Think of sleeping on a summer night...blankets are like coats of paint on your body. Thick...not so good when it's hot. Thin sheet, much better. No sheet, and maximum transfer of your heat to the surroundings.

Now, if we remove that paint off the stock intercooler, there will be some increase in efficiency(hence more power), but is it significant? I would estimate at maximum boost, maybe tops a 0.75-1.0% increase(2-3 HP). To be more qualitative, VERY controlled testing would have to be done to validate that number, but I'm confident it would be in that ballpark.

An aftermarket, direct replacement will not only cost money, but typically will create more turbo-lag, and will require a different turbo to get the same flexibility/drivability out of the motor(and I want the present system to be seam-less, as I have virtually little or no lag with my present 3.3L...:D).

I'll provide pic's once it's done.

As an engineer you should know that the emissivity of the black intercooler (assuming the paint is thin) is higher than a silver or polished intercooler so the heat transfer through radiation would be higher. Assuming the intercooler is hotter than the surrounding area, the higher emissivity would cause it to cool faster.

And the turbo-lag of a larger intercooler is virtually imperceivable, especially when it's only about twice the size. SmileWavy

Tilikum Turbo 09-16-2010 11:52 AM

Quote:

Originally Posted by David (Post 5564754)
As an engineer you should know that the emissivity of the black intercooler (assuming the paint is thin) is higher than a silver or polished intercooler so the heat transfer through radiation would be higher. Assuming the intercooler is hotter than the surrounding area, the higher emissivity would cause it to cool faster.

And the turbo-lag of a larger intercooler is virtually imperceivable, especially when it's only about twice the size. SmileWavy

That's a good point as far as black-body radiation, but the trade-off also would be that is also provides a soak from the engine bay, so it's somewhat a give and take. How "thin" is the paint in regards to the surface area, versus your earlier comments...I don't know if it was heavily researched by the supplier and Porsche working in conjunction for maximum payoff, or simply was just painted black, and that's that. The black paint will absorb like you say, but the duration of how quickly it them dissipates to the surroundings? I seem to remember in Thermodynamics class, the prof stating that there was no better transfer than direct, with no medium/buffer in the way.

My guess is, Porsche painted these as a corrosion barrier for the world market, since aluminum is susceptible to corrosion from elements(natural and man-made)

I think I want to stay stock on the intercooler...it's the one that was designed for this application by the factory. Maybe if the car one day goes to a twin-turbo beast, but I am very happy with it right now.

Thanks for your response.

:D

pdqcarrera 09-16-2010 02:28 PM

When I have the time I intend to use one of these shops to coat my Kokeln IC.

Thermal Barrier, Conductivity, Electrical by Swain Tech for Industrial Coatings including thermal spray plasma coating, metalizing closures, carbide metal coatings, ceramic plasma coating, hvof sprays, flame spray

Cradin Coatings

aerodyn930 09-16-2010 03:22 PM

Hello, I agree with previous posts regarding the more effective radiation with a dark finish, The Insulating properties of the paint are almost un measurable, We have done work in both design and modification of different I/C's and most are painted as per owners directions, Using our davtron in/out temp instrument I can honestly say that any difference has been very hard to detect.

So follow your heart and make it shine,

As a fellow engineer I applaud your quest for efficiency and would like to offer some tips during your I/C work.
First soak the unit with a suitable solvent then flush, Oil residue will coat the internal surfaces of the I/C reducing its efficiency, Even with a healthy turbo, cars that still have the breather connected to the air cleaner housing will exibit this.
Make sure that your rear baffle seal is in working order. If you can see your turbo and muffler when you look down behind the engine you need a new seal, A lot easier than you think to install abetter seal ( I will post photos if you wish) This is important as we combat heat soak during low speeds or at a standstill.
Last shim your recirc. valve and run a late model by-pass valve, In addition to quicker reaction time this mod reduces intake temps as compared to the factory set up.
Good luck on your quest,

Lou / AERO DYNAMICS

911st 09-18-2010 08:57 PM

Even Porsche seemed to see it's 930 IC was less than ideal.

The special 930SC had a larger intercooler that was the same size as the one the OEM maker built for RUF.

Then with the 91 turbo a much larger intercooler was fitted that had a more efficient BOV to.

Then there was the factory race Group B 930's that used a full bay intercooler built by Kremer for Porsche.

The stock IC might work ok for a sub 300hp street car but probably not much else. It might keep the velocity up but it is going to be more restrictive and create a pressure drop that will put the turbo at a higher pressure and lower efficiency than it could be and it is just dose not make for a great temp drop.

Usually changing the IC is good for 20 hp or so with no other changes.

It really is not worth doing much more than cleaning it unless you just like the look I suspect.


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