I was looking again at logs and just thought I would share this information. Intake TEMPS. Driving from the staging to the line the air intake temps were 116.6. Just before the 2step, the temps were 118.4. On the 2step, the temps were 120.2. All of 1st gear, the temps dropped back to 118.4 and 2nd gear they dropped again to 116.6. During and just after the 3rd gear shift, they dropped again to 114.8, then very briefly off and on through 3rd, they went from 114.8 to 113 and back to 114.8. During the shift to 4th they were at 113, then until 6600, they stayed at 114.8. From 6600 to 7200 they were 116.6 and from 7200 to about 8000 they were back to 118.4. Not sure of actual ambient temps, but off boost and moving at slow idle, they registered 116.6, which was exactly what the track had posted, 116 degrees. Pretty tough conditions with humidity, but I just wanted to show everyone how well the Race FMIC is working. Boost was 35+ and temps pretty much stayed at no more than 2 degrees above track temps and starting AIT. Not too shabby.

 

What was ambient temperature?

 

that's really good Tom, better than I would have hoped for.

 

9sec9, what IAT sensor are you using?

Seems like the majority of the sensors used have too much thermal mass to show anything real meaningful on post IC temps. I'm sure you are aware of this having talked to Grocmax on the RED testing and seeing the effort they put into their sensor package.

 

I guess you just can't accept anything for face value and have to try and discredit everything....

 

 

In my opinion the typical GM sensor is too slow. There are alternatives, been making my own NTC thermistor IAT's, only problem is even with a 2.2K pullup its so small and pulls enough current to self-heat, so calibration is a bit hard for those who wish to Plug n Play. Best solution is to use fine wire J type thermocouples potted in a 1/16th or 1/8th pipe thread nipple fitting and use the Analog Devices AD594x series of TC amp chips, works awesome for low temp stuff as you don't need to add any fancy filtering circuits when using the ECU +5v feed and sensor ground, cal is spot on and faster than lightning. To measure below 0c you'd need a negative voltage rail, and for above ~275c you need higher than +5v V+ but most of us never need that. The chips are CHEAP, add the proper PC board TC K type plug terminal and go to town. The output is linear and very easy to calibrate to an ECU.

http://www.analog.com/en/temperature...s/product.html


http://designtools.analog.com/Thermo.../Main.aspx#Top

 

How do you feel about these sensors being affected by heat soak?

And on the opposite side of the spectrum, when the intake pipes are 'iced down', how does it effect the response?

 

GrocMax, I was about to say that exact same thing. ......he says snickering as he walks away....

Really, I understand the need to maybe use something different, but the sensor was installed just prior to the TB. I'm sure it's AEM, but I stand to be corrected on that. Let's assume for a minute that 2 cars running the same sensor on an AEM EMS at the same track, same time, side by side. One of them is schit-from-shinola IC and the other is on a BR_FMIC. Will both of the temps be reading the same, even though the true difference is say 12 degrees between them, or will we be able to see a reasonable difference in the sensors? In other words, are those 2-4 degree variances I've seen going to be the norm, regardless of how truly efficient or inefficient an intercooler is? I would like to see similar log data from other IC's on the track.

 

I read the post. I'm just baffled how you have no clue what the temperature was at the event. I mean was it about 70, 80, 90, 100, or 110?

 

Tom, you have the GM AIT in the car, same one we use in every car. To answer your question, NO ABSOLUTELY FREAKING NOT will every intercooler show the same thing that ours did in your logs. (BTW, not yelling at you, just making a strong statement) Not even all of our FMIC's will measure the same so it's not like I am trying to slam someone else FMIC's. The AIT sensor is accurate and fast enough for what we are doing, as far as I am concerned.

Remember when you were here I was showing you the logs from the old original style 1G FMIC we use to make? The AIT's on a single gear pull went up to 197 degrees F? Then we swapped to the EVO core and built the new Race FMIC for the 1g's and lost almost 100 degrees of AIT's? The car gained like 80 whp. The sensor does operate correctly and will show you how well the FMIC is going.

I believe Robert at FP actually runs our Race FMIC on his EVO, doesn't he?

 

9sec9,
I've tuned a friends car with a fleebay core, GT42R, GM IAT sensor and a Hydra Nemesis ECU.

Going off the top of my head, I think we were seeing like 30-40 degree C temperature increases on a drag pass, but less then like 5 degree C on a dyno pull. The IC was complete crap but it really didn't show up until we hit the track. A dyno pull gave very little indication is was insufficient. I would bet the temps on the dyno were considerably higher then the 5 degree gain the sensor reported, but the pull was so quick that it didn't have time to really respond.

I would expect that the ~4 degree variation may equate to something probably less then a 10 degree total variation, but it's hard to say. But to answer your basic question, yes, I believe a crap IC would show significant differences compared to what you are seeing. I just don't think I would put a lot of confidence in the idea you are seeing nearly a 100% efficient intercooler.

Grocmax, thanks for the information. Without filtering, do you feel that sensor configuration would be stable enough to use as the main IAT sensor for fuel and spark correction or is this more for datalogging?

 

Yes Robert has your race core on his car. I ordered one ~1.5 weeks ago based on his recommendation for my EVO. (here's hoping it comes soon ).

I also have one of your old Spearco based race cores on my DSM. I haven't run it for a while but I used to see ~215F above 30psi on hot days here in Texas. The car made ~600whp in that trim 4 years ago, wish it had your new intercooler then. That was with a GM sensor as well.

 

Yes, its a damn good IC core, but with the sensor delay of several seconds any comps based on IAT get skewed, more so on ineffective IC's that have a large temp rise. Not nearly as much an overall effect on a drag car that has consistent predictable use, but street/road race apps it can really mess you up when the sensor is lying to you and 50F-60F behind.

 

Dan, thanks for ordering the race FMIC. The old 1g DSM core was the absolute best back in the day. We use to bolt those onto 12.0 DSM's with stock side mounts and drop ET's by .5 seconds. No AIT's back then to measure though with the stock ECU's and piggy backs of the day. The new DSM Race core we have now is the same core we use on the EVO's, kicks butt.

grocmax, I agree that lag in the sensor could be a problem. I don't feel the lag is there with the GM AIT though, hear me out on this. For example, on the dyno if the sensor was very laggy and being located in the upper i/c pipe don't you feel that you would see a rise in AIT's even after the pull was over? I would think so. I don't know how fast the sensor is and I am not argueing at all, I am just thinking out loud. If it was really slow I'd think it would continue to go up when the pull was over. Instead typically it starts to drop almost as soon as you lift off throttle.

What do you think?

A good test would be for me to take the sensor out of the pipe, log it and just pass a hair dryer over it quickly and see if it changes pretty quick or not. Anyone want me to try it?