TB993tt

Those of you who have been around a while, or used the search function will know my views on aftermarket intercoolers. Basically for the stock induction set up, the standard i/c is the best. The Andial and Protomotive may be better but I have seen zero proof of this, just anecdotes. For a pressure sensing induction, the $20K US Secan unit is the ticket and Jean has shown me some impressive numbers for his giant Protomotive unit.
Over the years, whenever a manufacturer has marketed an i/c I have asked for data about its efficiency compared to stock and noone has EVER come back with any, just the usual line about it being bigger, greater thermal efficiency etc etc.....
After Kevin's enthusiasm for Sportec I contacted them about their i/c which is based on the worse than stock TTP/Cargraphic/FVD unit - I told them it looked the same and that that unit does not work. Sportec assured me that they use different tanks and a much better core and to be fair it is about double the price of the TTP at $5K US.
Anyway to cut a long story short they agreed to let me try their I/C on my car at their UK distributor who happen to have a Maha chassis dyno. The deal is quite simple, I said I would guarantee to buy it IF it gains more than 10PS ANYWHERE on the power curve. They accepted these conditions - this wednesday.
I have not really crunched the numbers but I personally think this is a tall order and already have a bet on with the guy from my local shop. What does anyone think, to give 10PS, presumably at the higher end of the rev range (where the heat is greatest) will require a temp drop of what ? My engine dyno sheet indicates inlet temp of about 50degC @ 6500rpm using a stock I/C so how much drop would be needed to gain the 10PS ?
Also while on the dyno I want to do some overboost tests, to get the dyno to load up the motor and get some big boost. I regularly see 1.2bar @ 5750 rpm on overboost which should generate some decent numbers.

K24madness

It should be realistic TB. Currently your volume is a fixed number based on the size of your motor and the boost levels you run. You can however alter the density of the mixture thru cooler air. The new IC is one way to do it. Beside the abilty to cool more air the IC may have lower flow losses. What this means is that your turbos do not have to work as hard to produce the same levels of boost after the throttle body. Odd as it sounds the better IC will have a lower intake charge BEFORE the IC. Anytime you reduce the workload (Pressure Ratio) on the turbos you reduce the heat on the intake charge.

I have other ideas that will require a little more testing. One of them is the plastic inlet pipes that run from the metal Y pipe to the turbos. These pipes are responsible for heavy flow losses on the vacuum side of the turbos. I am in the process of having some fabricated for me. I will attempt to provide accurate data before and after the install. I wil also inquire about the price of other sets besides the ones for me.

SCARGO has done a carbon fiber version on the 996's They have had amazing results. Almost every car at the excellance car shootout in november had them. 50 WHT is not uncommon on a stock car. The ones for the 993 will not be made of carbon fiber.

Here is the theory behind lower vacuum losses and potentional increases.

Example of a intake with 4 lbs of vacuum as measured at the turbo inlet running 1 bar of boost. This would give you a pressure ratio of 2.74

Example of a intake with 1 lbs of vacuum as measured at the turbo inlet running 1 bar of boost. This would give you a pressure ratio of 2.14

Download any compressor MAP and look at the pressure ratios. You will see that as they go up the percentage goes down. When the percentage goes down it means the compressor is heating the air more.

That is a dramtic change. Same theory applies on the pressure side. Another thing for you to consider is a larger throttle body and opening up the lower chamber.

JJayB

TB
Your to be commended for sharing your test data. It isn't cheap or easy to be first and I know the intercooler has been an issue with you for sometime. My non scientific background leads me to an opinion based soley on my track experiences. I would think a dyno is a bit more complicated to duplicate a real life hp gains do to the static nature of the car no matter how many cooling fans they blow on the car. That said I think your bet is safe, however, if you droped your inlet temp 30 deg F
on a 50% humidity day it would be an easy 10hp. If your intercooler is within 2 deg.F of ambient temp, that would be a very effiecint intercooler. Can't wait for the results.

Kevin

TB, since you are making comparisons, back to back. Please purchase a garden sprayer.. I was on the Dyno (Mustang) yesterday, spraying water on the intercooler brings your cooler temps back down to "more real" driving conditions. If you want you can mix some alcohol with the water. Before the test, ask the techs to see if they have a Temp Heat Gun like a Raytek to measure core temps and tank temps. You can even read the temp on the turbine housings while doing the run, if you have some "big ones" Make sure the MAHO guys set the runs for at least 25 seconds so that the turbo's can load up.. Good Luck

TB993tt

Thanks for the replies
Madness
I have heard lots about the importance of flow, but the TTP one I had was supposed to flow much better than stock but still gave worse intake numbers - so the cores must have been REALLY bad. Regarding the inlet pipes - I don't think this is an area which was addressed when the major Euro tuners were developing their packages since the really high hp cars had the Secan/pressure sensing so just ran cone filters without the MAF - so keep us posted, if they work I will try a set
JJay
I agree about the static nature and expected Sportec to say that it would only work properly on the road or a specific test rig with the appropriate air flow, but hey all due respect to them for letting me try this.
Kevin
The problem with spraying the water is that the test has to in identical conditions for both I/Cs and there is no way I could accurately guage exactly how much water I was spraying and at what (critical) revs - so it could skew the results. BTW I am still admiring and trying to understand that last email about turbos you sent me

Kevin

TB;

I'm sorry I should have made myself more clear.. Spray the intercooler between runs!! You can see 30 degree reductions after the run. Even with large fans, you will be fighting heat soak from the engine. Water on the intercooler will stabilize your cooler..

K24madness

Kevin I was supprised when we dynoed my car that if we kept the lid closed and let it idle for a couple of minutes after the run the IC was only slightly warm to the touch.

Jean

TB great initiative and thanks for driving it. I would be very surprised if Ueli would take up this bet without being very confident of the results. As you put it earlier, reputations are at stake. In my opinion, the tests MUST be made both on the road and the rolling dyno as one of the cores can be much better dealing with heat soaking as a result of thickness etc.., while the other can be worse in circulating air through the fins. If in both situations one of the I/Cs performs better than the other then it is a clear result, otherwise, additional tests should be performed.

I expect results to be very similar under a dyno environment if the Sportec I/C is good, which it will be. Moreover, a less than 2% variance on your max HP is minimal, it could even happen between two runs with the same I/C.. If "run 1" with stock I/C yields better results than "run 2" with the Sportec I/C, then you should have a "run 3" with the stock I/C again to corroborate the numbers, therefore cancelling off engine and room temps (which were lower during "run 1").

You should really try to have a simple datalogging device measuring temps while on the run in similar weather and road conditions over a duration of 2-3 days. I know I know I am being ****

What I am more excited to hear about, is the difference between your hp readings and the ones of their car on the same dyno. Thanks for doing this, you keep the forum lively with your ideas and tests.

K24, my intercooler after 3-4 of minutes of idle in a closed environment is VERY hot to the touch. I don't know if that means something.

K24madness

Jean how is your seal around the IC and the lid? The fan pulls air through the IC if it has no other options. If air can pass around it or has another means of entry that is less restrictive than the IC core it will do so.

I was supprised since the first time I went to the dyno I left the lid up. After 3 pulls you could not keep you hand on the IC because it was to hot.

I also have to consider our two different conditions. Saudi is quite different than the bay area. FWIW the day I did the dyno it was 70+ degrees.

Jean

TB

Reading again your post I think the question you were rasing is how much you will need to drop the temperature to get to the 10hp gain? In my (very ) limited engineering knowledge, I think that what will improve your performance as far as intercooling is concerned is the charge density...the higher the density , the better it is. Cooler temperatures will yield higher density air and higher density will yield more hp.
So you need to calculate the change in density charge provided by the cooler and theoretically speaking that will translate into higher power. This is very rough as it does not take into consideration at all the difference in intercooler pressure loss between the two tested coolers, which has its own formula as well..
A 10hp increase at peak power is much more easily achievable than at lower levels since , as a percentage , it represents a smaller variance.

Density charge: (Initial absolute temp/Final absolute temp)-1
Based on the above, you will need to drop your temperature by 5-6 degrees Celsius to gain 1.8% incremental power (10 hp at maximum output of 541 PS). To get the 10 hp gain at lower RPM means that you will need to decrease the temperature by a much higher percentage.

K24 I have no sealing whatsoever or ducting around the intercooler, I had to destroy the wing to make it fit and it is now hardly closing.

K24madness

Its not a problem when under way you just don't get the benifits from the fan pulling air thru the core. At speed the air is pushed through it no problem.

TB993tt

My engine cutting out problem has not gone away (see two fuel pumps thread). I should be Ok for 5000rpm + on the chassis dyno but trying to ascertain overbbost torque looks like it will be a problem since the ECU applies the limiter briefly on some occasions. I talked to RS yeasterday and they are getting back to me today hopefully (I didn't mention the I/C test as they would tell me I'm mad). Something is obviously allowing the ECU to trip its limiter - ie too much boost/out of map range or that sort of combination. I wonder if it could be something dicky on one of the wastegates ?

tlark

As knowing little about the differing I/C's an how they apply to your discussion here if I may ask a ? about my stock set-up.

It was mentioned in a past thread about the black grill above the I/C being removed and again about the seals or ducting around the I/C in this thread.

Would the removal of this grill help us stock set-up guys that do the occasional 2-3 weekend DE stuff help (heat soak and/or benificial cooling) or would it be of no effect and similar to leaving the stock air box in our cars as designed.

I ask b/c over the weekend I ran into a guy at the track running a GT2 wing on his 993tt and the lower portion of his grills (black louvers) were removed. Granted the triangular inlets at the side of the wing were venting air into the I/C area but that was it. My ? arises from his not running a aux. oil cooler and him saying he didn't need to b/c this modification ruduced his oil temp. All stock set up, no mods other than minor exhaust mods, B & B headers.....
Not trying to hi-jack your guys thread here, just trying to learn and this advanced discussions is eduational.

TIA

TB993tt

Tom
My view is that Porsche put that grill there to change the angle of the incoming air so it hits the I/C cores at 90 deg for best effect (altho' it may be there for protection ?). I am not sure the grill fits the GT2 wing so that may be a reason to remove also as you say some people believe you get more flow without it. My tuner, RS chose to leave in place, so it stays.

Jean

I am not sure how much difference it makes, and whether we often tend to split hairs unnecessarily

My GT2 wing does not have the black grill because 1) I did not buy it and 2) it does not fit. In fact my intercooler is slightly touching the outer grill and pushing it upwards, I don't have any sealing around it and air must be moving in all directions above, under and around it.

I have driven my car which has large turbos, 1.1 Bar max settting, and 45 Degrees Celsius for a 1 hour spirited drive (read RPM rarely below 4-5k) in the desert and never saw my temp guage go beyond the 8-9 o'clock mark.

Furthermore, one of the fans of my front oil coolers is not working properly.

If I can drive my car under these conditions and not see high temps, I guess the grill, with or without it, will not make much difference, to people like me at least.

Net, net what I am trying to say is that yes it can be better or worse, but for 99% of us mortals who are not racing professionally everyday with our TTs, we will not notice any difference because of these small changes. A perfectionist would like to know of course but I would not loose my sleep over it (I did initially!)