There was some debate about my claims that the removal of my AC condensor fins in front of my stock intercooler was a total waste of time. Also there were some points made that not enough people are performing tests. So considering the fact that observing something is a more powerful means of determining its reality than debating about it, I could think of nothing more appropriate than to draw some scientific comparisons between data collected Before and After removing the fins on my AC condensor.
I used some laptop datalogging software (I will share details in the next days) to collect all of my ECM's sensor values and parameters during numerous wide open throttle (WOT) runs through 2nd gear, and some in 3rd gear. The main one of interest is the intake manifold temperature sensor (IA Temp).
Before:
A.) On 2004-01-05 I did a pull from 4000-5300 RPM in 2nd gear and IA Temp rose from 36.9*F to 59.7*F. Net rise: 22.8*F
B.) Next pull, same day. 4125-5300 RPM, IA Temp rose from 54.7*F to 73.0*F. Net rise: 18.3*F
C.) 3rd gear, 76-98 MPH, IA Temp rose from 63.5 to 71.4*F. Net rise: 7.9*F
D.) 3rd gear, 76-95 MPH, IA Temp rose from 76.3 to 81.9*F. Net rise: 5.6*F
E.) On 2004-02-29 in 2nd gear from 4100-5300 IA Temps rose from 79.5 to 90*F. Net rise: 10.5*F
F.) In 2nd from 4100-5300 again IA Temps rose from 78.8 to 96.1*F. Net rise: 17.3*F.
This gives an idea of some of the variances from run to run without actually changing anything. One cause for variance is current engine/IC temperature. Generally the subsequent runs were starting with a hotter engine/IC than the very first ones.
After:
G.) 2004-03-01, 2nd gear 4100-5300 RPM, IA Temp rose from 66.2 to 80.4. Net rise: 14.2*F
H.) 2nd gear 4100-5300 RPM, IA Temp rose from 76.3 to 91*F. Net rise: 14.7*F.
I.) 2nd gear 4175-5300 RPM, IA Temp rose from 87.3 to 99.7*F. Net rise: 12.4*F.
J.) 3rd gear from 76-98 MPH, IA Temp rose from 93.9 to 99*F. Net rise: 5.1*F.
K.) 3rd gear from 76-98 MPH, IA Temp rose from 102.6*F to 106.2*F. Net rise: 3.6*F.
In BOTH before and after, in virtually ALL tests, the IA Temp flatlined at 86 MPH. EVEN on a hot July top speed run (well to the top of 3rd anyway) with IA Temps in the 145*F range. By "flatlined" I mean they remained a constant temperature from that point forward no matter how long I stayed at WOT.
It also is important to note that the starting temperature is an important variable when comparing before/after results!. It seems the colder the starting temperature, the LARGER the Net Rise in temperatures is going to be. This makes sense because the turbo compressor output temperature is going to be applying a much larger temperature differential to a cold intercooler than it is, a really hot one that's almost the same temperature as the turbo outlet temperatures. So do not make the mistake of comparing the Net Rise of a pull starting at 90*F with one starting at 40*F.
Conclusions:
1.) The IC mod was worth a gain so negligible as to perhaps fall within the range of natural variance from run to run. For example let's compare Before runs E. and F. against After run H. In all three cases the 2nd gear starting temperature was around 77*F. Before AC fin removal, E and F show a net rise in temperature of 10 and 17 degrees. After AC fin removal, H shows a net rise of 14 degrees. Kinda makes one think the AC fin removal just doesn't make much of a difference.
If you average the Net Rise from Before to After (taking starting temps into consideration and the fact that after a certain point in 3rd gear, the temps don't increase further regardless of outside temperature), you might find a small reduction in temps. I however did not find this small increase to be worth it in the effort exerted in performing this modification, nor did I feel any difference in seat of the pants acceleration. I do encourage anyone else to calculate their own conclusions from my results, as I have not done very thorough calculations, I just ran the numbers and saw it to confirm what I had already suspected but I'm posting the raw data nonetheless, for your benefit.
2.) The fact that IA Temps flatlined at 86 MPH was interesting, but even more interesting was that they did not flatline at any lower of a speed after the IC mod. If the IC had become more efficient, I would expect it to dissipate heat earlier since it wouldnt require the benefit of "faster speed airflow" to achieve the equilibrium point.
3.) My Intake Manifold Temp sensor is probably not as good of a measurement as an actual air temperature sensor, but I beleive it to be a close enough approximation and it has been reliable in my tuning on my Syclone in the past (i.e. when significant gains/reductions in intake temperatures were known to occur, the IA Temp sensor did report a respective gain/drop.)
I also performed some before/after quarter mile calculation results (Formula is vehicle speed as read by VSS, accelerating over calculated distance, over time. Has shown to have good accuracy at dragstrip versus actual timeslips in AWD vehicle, FWD results not yet compared.) My results were a small increase in MPH, maybe 1 MPH, and no/negligible reduction in ET. This would coincide with my lack of seat of pants acceleration improvement.
Bottom Line:
(My opinion, please draw your own conclusions) This mod "might" make a very small improvement that you're unlikely to notice, but if you're keeping the stock intercooler and determined to extract every absolute last bit of performance possible, then performing this mod is not a bad idea, and from a performance standpoint you run no risk of reducing performance, but you do run a potential risk of damaging your A/C condensor and/or having a sore back for a few days.
I would be curoius to see what the results would be when it's colder out. That's the only time I noticed a difference. Thank you for posting the results.
It was 1*F out when I performed tests A-D. Although I do not have an "AFTER" set of data for similarly cold conditions. For the rest of the data, fortunately I have Before results E and F which are similar outside temperatures to those during After G-K.
And, you're welcome. :D
Man I hate to do this to someone who went to so much effort, and that was a lot of great effort!!!!!!!!!! :D But using the IAT for this test is wrong. I know it sounds odd but it is too influenced by the heat soak and coolant temps of the engine!!! To prove this further, there are MANY Compensation Tables, Filters, Offsets etc in the chip working to make up for this heat soak and coolant temp effect on the IAT, and those tables are not even close. Scott Sealander who is a chip tuning/programming genius got so fed up with trying to calibrate these tables he decided to swap over to a MAF setup!! Even with his very high skill level, he could not change those MAP ONLY chip tables enough to work correctly, SO the IAT is not a good reference! Best for your test to use temp sensors before and after the intercooler (and pressure sensors while you are there!). Before and after the intercooler will be exact on what the mod does for you! I used a digital temp meter and fast acting temp sensors, this meter has dual display and differential display and logging capabilities. My CFM test too (if you want to do those as well!) shown a change from 150 cfm to 350 cfm using the Secondary Cooling Fan running before and after the fin mod. Don?t give up testing though!!!
Jeff M
Quote from: TookyCatThere was some debate about my claims that the removal of my AC condensor fins in front of my stock intercooler was a total waste of time.
Nice information. Thanks for the effort!
I tend to agree with you. This is probably not a very useful mod. But it is free.... I added some code to trigger the second fan whenever there is boost. This way if you are not moving, the fan will come on to slow down the heating of the intercooler. The intercooler has no excess capacity, so no need to prematurely heat it up. I have NEVER seen the intercooler output temp go down, once you get into boost. It always rises. So if you start with a hot intercooler, you will end with an even hotter intercooler. This is one reason I don't like an open air filter under the hood. If you are not moving, the intercooler is heating up from the warm underhood air.
I do not use the manifold location for the air temp sensor anymore, as I feel the air temp density is not as accurate when it is located there. (The MAP sensor is now hooked where the IAT was.) The stock TGP code uses the manifold air temp directly to look up the air density term. It does not use a derived term as some other code does. So obviously the IA term is very important to determine how much fuel to inject.
I moved the IAT to the output of the intercooler, and set up some code to enable the CylAirTemp to be derived from some added factors. This CylAirTemp value now comes out in the ALDL stream in the StartUp coolant temp position, so one can monitor the air temp being used to determine air temp density. Took a while to get the factors right, but the fueling seems to be pretty good over a large range of temps.
As an aside, I do have a B-body LT1 MAF mounted in my TGP's intake tract. I use it to compare the SD calculated airflow to the actual airflow. The MAF airflow data is also used to calculate actual VE. Both these values come out in the ALDL data stream. The MAF is not used to calculate fuel. If one wants to use a MAF, I would take a look at the 3300 code used in some Olds. Code ID is DF. There is probably some EGR differences, but this is a possiblity.
About two years ago, the TGP also got a 3 bar MAP sensor. Probably the only TGP using one with what at least started out as 8F code. I also changed to one VE table, as I did not like the two VE tables that GM uses. I think it is kind of clunky to have to add the two VE values together.
Scot
Quote from: ScotSeaThe MAF is not used to calculate fuel. If one wants to use a MAF, I would take a look at the 3300 code used in some Olds. Code ID is DF. There is probably some EGR differences, but this is a possiblity.
The difference being that the 3300 doesn't have EGR. :P :D
Quote from: ScotSeaI tend to agree with you. This is probably not a very useful mod. But it is free.... I added some code to trigger the second fan whenever there is boost.
Maybe not the most awesome free mod, it's not that bad of a mod though, quite a bit less is the Throttle Body Coolant Bypass Mod that is done :) . I tend to support the intercooler mod and offer below a link to our intercooler and its efficiency based on MPH of wind blowing through it, which can roughly be converted to CFM, either way more air going over it helps but that intercooler could use upgrading too. It's great to see some advancements in turbo design, and detailed specs on those, but intercooler spec sheets are still vague for what you really want to know from an application standpoint. The TGP chip got used by ATR on their super setups running the best times for their collection of show vehicles, sure it made consistency difficult for them, I believe they preferred it since they had the 2,000 page operations manual to fully explain the chip usage. Only wish the chip?s IAT Boost Timing Compensation Table was looked at for people. Careful in the snowy months, Secondary Fan might munch on the snow if you get some buildup in there 8)
http://www.turbograndprix.com/TGPintercooler1.jpg
Quote from: ScotSeaAbout two years ago, the TGP also got a 3 bar MAP sensor. Probably the only TGP using one with what at least started out as 8F code. I also changed to one VE table, as I did not like the two VE tables that GM uses. I think it is kind of clunky to have to add the two VE values together. Scot
Umm, an exercise to do it? Past 15 psi, maybe a turbo upgrade to go with those 29lb injectors, nice! Yours is a white TSTE right?
Jeff M
Quote from: skalorQuote from: ScotSeaThe MAF is not used to calculate fuel. If one wants to use a MAF, I would take a look at the 3300 code used in some Olds. Code ID is DF. There is probably some EGR differences, but this is a possiblity.
The difference being that the 3300 doesn't have EGR. :P :D
The 3300 does not have an EGR valve, but it does have EGR code in the ECM. That is what I was refering to. I was just wondering if it was the 3 bit digital, or a PWM style. It is the PWM style.
BTW, the CodeId is 'D4' not 'DF'. It does not use an IAT, or the MAP sensor, but it looks like those inputs are not used elswhere, so they could be installed, and used, as long as the code is added to use them.
Scot