mjims

I know this is a well discussed subject, but I was wondering what the general feelings towards the best Intercooler upgrade is?

I understand from TB that the Secan Intercooler is by far the best, but at the price it's just to expensive.

So considering the rest, Which is the best one and where is the best place to purchase one from?

K24madness

I like the Andial unit. It allows you to retain the factory apperances. The manor in which they increased core size may not be the best from a cooling point of view but by reducing pressure losses thru the IC the turbos do not have to work as hard thus they produce less heat.

Many well respected tuners feel the pressure losses are more important than the cooling abilty of the IC.

TB993tt

Madness, don't you mean by improving flow the turbos do not have to work hard etc...
pressure loss (drop) will potentially increase as one increases the volume of the core ?
I bought into both the above arguments when I bought the TTP/Cargraphic?FVD unit but I'm back to stock again
Jim, not only is the Secan prohibitively expensive but it also requires a different induction system.

Jim Morton

TB:

If you don't mind my asking, why did you go back to the stock IC???

I am about to mount my CG intercooler as I can see no down side to using it. The cross sectional area of the intake air flow path seems better than stock and the thicker core should provide for better heat exchange. I am fabbing my own top baffle to better address the fitment to the decklid, but the cooler itself seems OK.

If you know of any issues, I would appreciate the insight.

Thanks !

TB993tt

Jim
I was told by RS Tuning that the stock one was better and I could get more power by reverting to stock. I did a before/after inlet temp test under constant conditions with both coolers back to back and the stock one gave lower inlet temps, 5 or 8% lower (its a thread somewhere on here).

mjims

The More people I talk too, the more say don't bother upgrading. Stick to the standard one.

If andial just replace the core and utilise the standard middle and ends, how can it not be more efficient?

Jean

Jim

I think I recall that you had a Protomotive I/C..Do you feel it is limiting your output with the K24s?

As far as Andial, my guess is that the core they use is not as efficient as the stock one under certain parameters and turbo sizing.. I think recalling reading fromTB that RS Tuning did a test on them and found them less efficient than stock. Maybe not, my memory is not as good anymore.

mjims

Hi Jean,

Your memory is certainly good enough to remeber that I am indeed running the Protomotive Intercooler.

I'm currently in the middle of Mapping the Motronic on a dyno and we discovered that it had cracked in one of the joints and was leaking boost. I put the standard one back on whilst the Protomotive was being repaired, and wondered as too the efficencies of the other type available.

The Protomotive Intercooler looks fantastic.... but it is completely hand made, with every bend being hand welded rather than a cast section welded on and the core runs 'north-south' rather than the 'east-west' of most systems. So It got me thinking as to the air track through it, as it hits a sharp bend on entering the core and again in order to get across to the throttle body. The Standard one has immediate entry to the core and only hits one bend into the throttle body.

As one of the welds failed I'm a little worried that if happens again It wont be obviously noticable and I destroy the engine.


The standard intercooler in comparison is a fabulous physical fit against the rather fiddle job of getting the Protomotive one on and off.

K24madness

TB

Pressure loss will decrease with the proper designed IC. The 993tt takes boost signal from the intake manifold. Any pressure loss before the intake manifold requires that the turbos have to work harder to produce desired boost at the intake manifold. The harder the turbos work the more heat they produce.

You can check the IC by placing a gauge before and after the IC then compiaring the difference. A good IC will show less than 2 psi pressure drop.

mjims

The larger the volume of the intercooler the more air required to fill it hense the more pressure loss. Surely?

Jean

Jim,

Thanks, Glad to know I still have some neurones left

Yes I heard that the Proto I/C is an engineering nightmare to make it fit.. the stock one is certainly much nicer. Concerning the bends, I would not worry too much as they do not impact as much the efficiency or flow characteristics, maybe around 1% for a sharp bend, especially when they are wide bends rather than narrow, it won't be that bad. You are right about pressure, it is impacted by the drag of air inside the I/C which is driven by the distance travelled but also by the number of channels inside the core and their width and length, a very large but efficient core could have very small pressure drops if properly built, so the key is how the core is built and what material was used.. End tanks play a role too in the flow characteristics.

Jim Morton

Thanks guys for the replies.

IMHO, it seems like we have a few overlaps of flow theory going on here. This is how I would put this together so far.

Pressure loss across an intercooler should be caused by either a restriction of flow, usually a reduction in cross sectional area or friction losses due to length effects or flow bends/deflection.

This said, with a larger intercooler volume, the time to build pressure in front of the throttle plate will increase with increased intercooler volume. Put simply, the compressor needs to fill a larger volume before pressue can build. With the larger volume comes greater time will be required given the same turbo compressor. Right??? (Kevin???)

In the end, the theory of intercoolers, as I understand this, is that the time lag created by using the larger intercooler is offset by the lowering of the charge air temps on the output side of the intercooler. If the larger intercooler does not accomplish this lowering of charge air temp, it does nothing but give possible "eye candy" to the owner.

Given the "on the bench" observation of the CG intercooler and its design/build, I would expect a slight increase in boost lag, but should see better reduction in charge air temps over the stock IC. If folks have not seen this in practice, I would be darn curious as to why as it would suggest something related to the airflow characteristics of the installation, such as air stalling or ???

Anyway all the above said, has anyone (TB?) specifically tested the IC's both on and off the car for looking further into why the larger cooler did not produce better steady state results???

Boy do I wish I had more time and $$$ to explore this stuff... It's way to much fun!!!

Midlife (and parenthood) comes with its comprimises...

K24madness

No that is not the case.

Imagine a 4 row IC core vs a 6 row IC core using the same end tank and core design. Using the same pressure and flow which do you think would offer the greater resistance to the air?

Greater resistance= higher pressure losses.

Higher pressure losses= higher pressure ratios

Higher pressure ratios=more heat

Low pressure loss is the MOST important feature of the IC.

TB993tt

Madness
Firstly how can a 6 v 4 row use exactly the same end tank - surely the 6 row would have to be bigger ?
Greater resistance means greater back pressure not pressure loss - same effect that the turbos have to work harder and produce more heat but not the same thing. Pressure loss is a relative term ie loss compared with the stock I/C which comes through increased I/C volume ?
Jim M
Yes, its a great subject and I love it when people try and simpify it with statements like bigger=better thermal efficiency. In the 90's RS Tuning spent a lot of time attempting to make an I/C to rival the Secan, I saw half a dozen prototypes on their shelves - none of them worked better than stock when tested on the engine dyno with air forced through at up to 300kph - hence they won't try and flog you an I/C

Jim Morton

TB ( and others...)

As yesteday was fairly empty chores-wise, I opted to test fit and analyze the Cargraphic/FVD/others(?) intercooler I have on the bench.

At first glance I could only see how this cooler should work out to be better than stock. There are 21 charge air passages to the stock coolers 17. The cooler air passage sections have larger cross sectional areas than the stock one as well (The core is quite a bit thicker). The cooling waffles are thinner and better spaced for improved air flow. All in all, sitting on the bench, this IC had to be better than stock, right???

Well...After test fitting the cooler, I found the fitment to be far from precise or even adequate. The cooler sits too high to the decklid grill at the rear of the cooler to provide a good high pressure air zone aboce the IC cores. The supplied baffle plate poorly addresses the cold air snorkel for engine intake air as well as the HVAC system. I suppose some folks might forego the pleasantries of the HVAC and could ignore this, but I expected something considerably better given what these various tuners charge for this "catalog" piece.

In addition to the aboe, when looking under the cooler while mounted, there is poor ducting away from the bottom of the core. Lots of places to "stall" the air flow. All in all, it was a dissapointing first test fit !

As the day wore on, I continued to be bothered by this and took another looks. I knew that some folks on this board have fitted this cooler and have showed good results. This in mind, I took another look at my cooler vs. others who have posted pix. I am now thinking that these IC's may be mis-machined on the throttle body face causing the back of the cooler to be too high and not allowing a good baffle plate to be used. Tomorrow, I am going to attempt to fixture the IC on my Deckel 6 axis CNC mill and face the mating face down a scoche and add 1 degree of additonal angle to the mount, lowring the rear of the IC 10mm. Lots of "meat" on the casting in this area, so no big deal.

I think that if I can gain some area below the grill, make a new, better grill baffle to this cooler as well as fab a new cold air snorkel and under IC air diverters, this IC might be worth a test try vs. stock.

I will post some pictures as things progress. With my day job, this might take a few weeks...

I might also fit some instrumentation test ports for before and after IC charge air temp readings.

All in all, the very next challenge is hold this beast on the mill table. Hopefully, I can secure this thing. After all, someone did it when it was made...right??? More to follow.

Regards